rules and regulations classification of a floating offshore installation at...

Part 11Production, Storage and Offloadingof Liquefied Gases in BulkJune 2013

Rules and Regulationsfor theClassification of aFloating Offshore Installation at a Fixed Location

Lloyd’s Register is a trading name of Lloyd’s Register Group Limited and its subsidiaries. For further details please see http://www.lr.org/entities

Lloyd's Register Group Limited, its affiliates and subsidiaries and their respective officers, employees or agents are, individually and collectively, referredto in this clause as ‘Lloyd's Register’. Lloyd's Register assumes no responsibility and shall not be liable to any person for any loss, damage or expensecaused by reliance on the information or advice in this document or howsoever provided, unless that person has signed a contract with the relevantLloyd's Register entity for the provision of this information or advice and in that case any responsibility or liability is exclusively on the terms and conditions set out in that contract.

PART 1 REGULATIONS

PART 2 RULES FOR THE MANUFACTURE, TESTING AND CERTIFICATION OF MATERIALS

PART 3 FUNCTIONAL UNIT TYPES AND SPECIAL FEATURES

PART 4 STEEL UNIT STRUCTURES

PART 5 MAIN AND AUXILIARY MACHINERY

PART 6 CONTROL AND ELECTRICAL ENGINEERING

PART 7 SAFETY SYSTEMS, HAZARDOUS AREAS AND FIRE

PART 8 CORROSION CONTROL

PART 9 CONCRETE UNIT STRUCTURES

PART 10 SHIP UNITS

PART 11 PRODUCTION, STORAGE AND OFFLOADING OF LIQUEFIED GASES IN BULK

Chapter 1 General

2 Ship Survival Capability and Location of Cargo Tanks

3 Ship Arrangements

4 Cargo Containment

5 Process Pressure Vessels and Liquids, Vapour and Pressure PipingSystems

6 Materials of Construction and Quality Control

7 Cargo Pressure/Temperature Control

8 Vent Systems for Cargo Containment

9 Cargo Containment System Atmosphere Control

10 Electrical Installations

11 Fire Prevention and Extinction

12 Artificial Ventilation in the Cargo Area

13 Instrumentation and Automation Systems

14 Personnel Protection

15 Filling Limits for Cargo Tanks

16 Use of Cargo as Fuel

17 Special Requirements

18 Operating Requirements

19 Summary of Minimum Requirements

Appendix 1 Non-Metallic Materials

1LLOYD’S REGISTER

Part 11RULES AND REGULATIONS FOR THE CLASSIFICATION OF A FLOATING OFFSHORE INSTALLATION AT A FIXED LOCATION, June 2013

Chapter Contents

© Lloyd's Register Group Limited 2013. All rights reserved.

Except as permitted under current legislation no part of this work may be photocopied, stored in a retrieval system, published, performed in public, adapted, broadcast, transmitted, recorded or reproduced in any form or by any means, without the prior permission of the copyright owner. Enquiries should be addressed to Lloyd's Register Group Limited, 71 Fenchurch Street, London, EC3M 4BS.

Part 11

CHAPTER 1 GENERAL

Section 1.1 Application1.2 Definitions

LR 1.3 Alternative arrangementsLR 1.4 Survey requirementsLR 1.5 Class notations and descriptive notesLR 1.6 Information and plans

CHAPTER 2 SHIP SURVIVAL CAPABILITY AND LOCATION OF CARGO TANKS

Section 2.1 General2.2 Freeboard and stability2.3 Damage assumptions2.4 Location of cargo tanks2.5 Flood assumptions2.6 Standard of damage2.7 Survival requirements

CHAPTER 3 SHIP ARRANGEMENTS

Section 3.1 Segregation of the cargo area and cargo tank holds3.2 Accommodation, service and machinery spaces and control stations3.3 Cargo machinery spaces and turret compartments3.4 Cargo control rooms3.5 Access to spaces in the cargo area3.6 Airlocks3.7 Bilge, ballast and oil fuel arrangements3.8 Tandem and side-by-side loading and unloading arrangements

CHAPTER 4 CARGO CONTAINMENT

Section 4.1 Definitions4.2 Application

Part A Cargo containment4.3 Functional requirements4.4 Cargo containment safety principles4.5 Secondary barriers in relation to tank types4.6 Design of secondary barriers4.7 Partial secondary barriers and primary barrier small leak protection system4.8 Supporting arrangements4.9 Associated structure and equipment

4.10 Thermal insulationPart B Design loads

4.11 General4.12 Permanent loads4.13 Functional loads4.14 Environmental loads4.15 Accidental loads

Part C Structural integrity4.16 General4.17 Structural analyses4.18 Design conditions

Part D Materials and construction4.19 Materials4.20 Construction processes

3LLOYD’S REGISTER

RULES AND REGULATIONS FOR THE CLASSIFICATION OF A FLOATING OFFSHORE INSTALLATION AT A FIXED LOCATION, June 2013

Contents


Part 11

4 LLOYD’S REGISTER

Contents

Part E Tank types4.21 Type A independent tanks4.22 Type B independent tanks4.23 Type C independent tanks4.24 Membrane tanks4.25 Integral tanks4.26 Semi-membrane tanks

Part F Guidance4.27 Guidance Notes for Chapter 4

CHAPTER 5 PROCESS PRESSURE VESSELS AND LIQUIDS, VAPOUR AND PRESSURE PIPING SYSTEMS

Section 5.1 General5.2 System requirements5.3 Arrangements for cargo piping outside the cargo area5.4 Design pressure5.5 Cargo system valve requirements5.6 Cargo transfer arrangements5.7 Installation requirements5.8 Piping fabrication and joining details5.9 Welding, post-weld heat treatment and non-destructive testing

5.10 Installation requirements for cargo piping outside the cargo area5.11 Piping system component requirements5.12 Materials5.13 Testing requirements

CHAPTER 6 MATERIALS OF CONSTRUCTION AND QUALITY CONTROL

Section 6.1 Definitions6.2 Scope and general requirement6.3 General test requirements and specifications6.4 Requirements for metallic materials6.5 Welding of metallic materials and non-destructive testing

LR 6.6 Specific welding requirements for liquefied petroleum gas and liquefied natural gas systems6.7 Non-metallic materials

CHAPTER 7 CARGO PRESSURE/TEMPERATURE CONTROL

Section 7.1 Methods of control7.2 Design of systems7.3 Reliquefaction of cargo vapours7.4 Thermal oxidation of vapours7.5 Pressure accumulation systems7.6 Liquid cargo cooling7.7 Segregation7.8 Availability

CHAPTER 8 VENT SYSTEMS FOR CARGO CONTAINMENT

Section 8.1 General8.2 Pressure relief systems8.3 Vacuum protection systems8.4 Sizing of pressure relieving system

ContentsRULES AND REGULATIONS FOR THE CLASSIFICATION OF A FLOATING OFFSHORE INSTALLATION AT A FIXED LOCATION, June 2013

Part 11

LLOYD’S REGISTER 5

CHAPTER 9 CARGO CONTAINMENT SYSTEM ATMOSPHERE CONTROL

Section 9.1 Atmosphere control within the cargo containment system9.2 Atmosphere control within the hold spaces (cargo containment systems other than Type C

independent tanks)9.3 Environmental control of spaces surrounding Type C independent tanks9.4 Inerting9.5 Inert gas production on board

CHAPTER 10 ELECTRICAL INSTALLATIONS

Section 10.1 General requirements10.2 Definitions

CHAPTER 11 FIRE PREVENTION AND EXTINCTION

Section 11.1 Fire safety requirements11.2 Fire mains and hydrants11.3 Water-spray system11.4 Dry chemical powder fire-extinguishing systems11.5 Enclosed spaces containing cargo handling equipment11.6 Firefighters’ outfits

CHAPTER 12 ARTIFICIAL VENTILATION IN THE CARGO AREA

Section 12.1 Spaces required to be entered during normal cargo handling operations12.2 Spaces not normally entered

CHAPTER 13 INSTRUMENTATION AND AUTOMATION SYSTEMS

Section 13.1 General13.2 Level indicators for cargo tanks13.3 Overflow control13.4 Pressure monitoring13.5 Temperature indicating devices13.6 Gas detection13.7 Additional requirements for containment systems requiring a secondary barrier13.8 Automation systems13.9 System integration

CHAPTER 14 PERSONNEL PROTECTION

Section 14.1 Protective equipment14.2 First-aid equipment14.3 Safety equipment

CHAPTER 15 FILLING LIMITS FOR CARGO TANKS

Section 15.1 Definitions15.2 General requirements15.3 Default filling limit15.4 Determination of increased filling limit15.5 Maximum loading limit15.6 Information to be provided to the Operator

ContentsRULES AND REGULATIONS FOR THE CLASSIFICATION OF A FLOATING OFFSHORE INSTALLATION AT A FIXED LOCATION, June 2013

Part 11

LLOYD’S REGISTER6

CHAPTER 16 USE OF CARGO AS FUEL

Section 16.1 General16.2 Use of cargo vapour as fuel16.3 Arrangement of spaces containing gas consumers16.4 Fuel gas supply16.5 Fuel gas plant and related storage tanks16.6 Special requirements for main boilers16.7 Special requirements for gas-fired internal combustion engines16.8 Special requirements for gas turbines16.9 Alternative fuels and technologies

LR 16.10 Survey

CHAPTER 17 SPECIAL REQUIREMENTS

Section 17.1 General17.2 Flame screens on vent outlets17.3 Cargo pumps and discharge arrangements17.4 Carbon dioxide – High purity17.5 Carbon dioxide – Reclaimed quality

CHAPTER 18 OPERATING REQUIREMENTS

Section 18.1 General18.2 Cargo operations manuals18.3 Cargo information18.4 Suitability for storage18.5 Storage of cargo at low temperature18.6 Cargo transfer operations18.7 Personnel training18.8 Entry into enclosed spaces18.9 Cargo sampling

18.10 Cargo emergency shut-down (ESD) system18.11 Hot work on or near cargo containment systems18.12 Additional operating requirements

CHAPTER 19 SUMMARY OF MINIMUM REQUIREMENTS

Section 19.1 Explanatory notes to the summary of minimum requirements

APPENDIX 1 NON-METALLIC MATERIALS

Section 1 General2 Material selection criteria3 Properties of materials4 Material selection and testing requirements5 Quality control and quality assurance (QA/QC)6 Bonding and joining process requirement and testing7 Production bonding tests and controls

General

Section

1.1 Application

1.2 Definitions

LR 1.3 Alternative arrangements

LR 1.4 Survey requirements

LR 1.5 Class notations and descriptive notes

LR 1.6 Information and plans

Guide to the reader

This Part incorporates risk mitigation measures taken andadapted from the International Code for the Construction andEquipment of Ships Carrying Liquefied Gases in Bulk (IGCCode). However, if alternative measures have been definedfor an installation, in accordance with the operating philoso-phy or safety philosophy of the installation, these alternativemeasures may be considered.

All paragraphs, Figures and Tables taken from the publishedIGC Code, including any IGC Code amendments up to thedate of publication of these Rules, are prefixed with the corresponding IGC Code paragraph numbers, e.g., 2.1.1.

Where IGC Code content has been modified in order forapplication to ship units engaged in the production, storageand offloading of liquefied gases at a fixed location, therevised text is shown underlined. Where paragraphs, Figuresand Tables have been taken from the IGC Code and renumbered, the modified number(s) are shown underlined,e.g., 1.2.3.

In general, for the purposes of classification, the words‘should be’ in IGC Code text are to be read as ‘is to be’ or‘are to be’, as appropriate.

IGC Code content which is not considered applicable and/orbeneficial to the objective of these Rules has not beenincluded, to prevent misapplication.

Paragraphs, Figures and Tables which do not appear in theIGC Code are prefixed by 'LR’, e.g., LR 1.1.1.

1.1 Application

LR 1.1.1 The purpose of this Part is to providerequirements to ensure the safe operation and inspection/maintenance of ship units engaged in the production, storageand offloading of liquefied gases at a fixed location. Ship unitsengaged solely in the storage and offloading of liquefied gasesat a fixed location are also to comply with this Part, asapplicable.

LR 1.1.2 The requirements in this Part are applicable tohull construction in steel.

LR 1.1.3 This Part considers only the designrequirements for the production, storage and offloading ofliquefied gases of the unit. Ship units are to comply with Part10 and other relevant Parts in addition to the requirements ofthis Part.

LR 1.1.4 The requirements prescribed in this Part areapplicable only to liquefied hydrocarbon gases (liquefiednatural gas and liquefied petroleum gas), nitrogen and carbondioxide. The products for which this Part is applicable arelisted in Chapter 19. Requirements are not prescribed forproducts that are considered toxic by the IGC Code.Proposals to produce, store and offload products not listedin Chapter 19 are to be individually considered and thearrangements are to be acceptable to the Administration.

LR 1.1.5 Integral tanks, that form a structural part of thehull, for the storage of gas condensate are to comply withPart 10, see Pt 10, Ch 1,1.1.12.

LR 1.1.6 Integral tanks, that form a structural part of thehull, for the bulk storage of liquid chemicals necessary fortreatment of the feed gas, e.g., monoethylene glycol (MEG)and amine solvents, are to comply with Part 10, see Pt 10,Ch 1,1.1.13. The structural design of independent tanks forthe bulk storage of liquid chemicals is to comply with therequirements of Chapter 4 and Pt 10, Ch 1,1.1.13(b) and (c).

1.1.1 Flammable liquids having a flashpoint of 60°C(closed-cup test) or less and the flammable products listed inChapter 19 shall not be carried in tanks located within theprotective zones described in 2.4.1, within the longitudinalextent of the hold spaces for those tanks.

1.1.2 Where a risk assessment or study of similar intent isutilised within this Part, the results shall also include, but notbe limited to, the following as evidence of effectiveness:• Description of methodology and standards applied;• Potential variation in scenario interpretation or sources

of error in the study;• Validation of the risk assessment process by an

independent and suitable third party;• Quality system under which the risk assessment was

developed;• The source, suitability and validity of data used within the

assessment;• The knowledge base of persons involved within the

assessment;• System of distribution of results to relevant parties;• Validation of results by an independent and suitable third

party.

LR 1.1.7 The risk and consequences of stratificationand rollover of liquefied gas in storage tanks are to beconsidered. Methods to reduce the possibility of stratificationare to be considered, e.g.:• ability to fill the tank from both the top and bottom;• recirculation of tank inventory through jet nozzles or

other mixing devices.Methods to detect stratification are also to be considered.


Part 11, Chapter 1Section 1


General

1.2 Definitions

Except where expressly provided otherwise, the followingdefinitions apply to this Part. Additional definitions areprovided in Chapters throughout this Part.

1.2.1 Accommodation spaces are those spaces usedfor public spaces, corridors, lavatories, cabins, offices, hospitals, cinemas, games and hobby rooms, barber shops,pantries without cooking appliances and similar spaces.

1.2.2 ‘A’ class divisions are divisions as defined inRegulation II-2/3.2 of the SOLAS Convention.

LR 1.2.1 Administration is defined in Pt 1, Ch 2,1. Forthe purpose of classification, the definition of Administration isto be taken as Lloyd's Register (LR).

1.2.3 Boiling point is the temperature at which a productexhibits a vapour pressure equal to the atmospheric pressure.

1.2.4 Breadth, B, in metres, means the maximumbreadth of the ship unit, measured amidships to the mouldedline of the frame.

LR 1.2.2 For the determination of the scantlings for hullconstruction, the breadth, B, is to be taken as defined in Pt 4,Ch 1,5.

1.2.5 Cargo area is that part of the ship unit whichcontains the cargo containment system and cargo pump andcompressor rooms and includes the deck areas over the fulllength and breadth of the part of the ship unit over thesespaces. Where fitted, the cofferdams, ballast or void spacesat the after end of the aftermost hold space or at the forwardend of the forwardmost hold space are excluded from thecargo area.

1.2.6 Cargo containment system is the arrangement forcontainment of cargo including, where fitted, a primary andsecondary barrier, associated insulation and any interveningspaces, and adjacent structure if necessary for the supportof these elements. If the secondary barrier is part of the hullstructure it may be a boundary of the hold space.

1.2.7 Cargo control room is a space used in the controlof cargo handling operations.

1.2.8 Cargoes are products, listed in Chapter 19, thatare carried in bulk by ship units subject to the requirementsof this Part.

1.2.9 Cargo machinery spaces are the spaces wherecargo compressors or pumps, cargo processing units, arelocated, including those supplying gas fuel to the engineroom.

1.2.10 Cargo pumps are pumps used for the transfer ofliquid cargo, including main pumps, booster pumps, spraypumps, etc.

1.2.11 Cargo service spaces are spaces within the cargoarea used for workshops, lockers and storerooms that are ofmore than 2 m2 in area.

1.2.12 Cargo tank is the liquid-tight shell designed to bethe primary container of the cargo and includes all suchcontainment systems whether or not they are associated withthe insulation or/and the secondary barriers.

1.2.13 Closed loop sampling is a cargo sampling systemthat minimises the escape of cargo vapour to the atmosphereby returning product to the cargo tank during sampling.

1.2.14 Cofferdam is the isolating space between twoadjacent steel bulkheads or decks. This space may be a voidspace or a ballast space.

1.2.15 Control stations are those spaces in which theship unit’s radio or emergency source of power is located, orwhere the fire recording or fire control equipment iscentralised. This does not include special fire control equip-ment, which can be most practically located in the cargo area.

1.2.16 Flammability limits are the conditions defining thestate of fuel oxidant mixture at which application of anadequately strong external ignition source is only just capable of producing flammability in a given test apparatus.

1.2.17 Flammable products are those identified by an ‘F’in column ‘f’ in the Table in Chapter 19.

1.2.18 FSS Code is the Fire Safety Systems Code mean-ing the International Code for Fire Safety Systems as adoptedby the Maritime Safety Committee of the Organisation byResolution MSC.98(73), as amended.

1.2.19 Gas carrier is a cargo ship constructed or adaptedand used for the carriage in bulk of any liquefied gas or otherproducts listed in Chapter 19 of the IGC Code.

1.2.20 Gas Combustion Unit (GCU) is a means of disposingof excess cargo vapour by thermal oxidation, see also 1.2.49.

1.2.21 Gas consumer is any unit within the vessel usingcargo vapour as a fuel.

1.2.22 Hazardous area is an area in which an explosivegas atmosphere is, or may be expected to be present, inquantities that require special precautions for the construc-tion, installation and use of electrical equipment. When a gasatmosphere is present the following hazards may also bepresent: toxicity, asphyxiation, corrosiveness, reactivity andlow temperature; these hazards shall also be taken intoaccount and additional precautions for the ventilation ofspaces and protection of the crew will need to be considered.

1.2.23 Hold space is the space enclosed by the structureof the ship unit in which a cargo containment system is situated.

1.2.24 IBC Code means the International Code for theConstruction and Equipment of Ships carrying DangerousChemicals in Bulk adopted by the Maritime Safety Committeeof the Organisation by Resolution MSC.4(48), as amended.



LLOYD’S REGISTER2

General

1.2.25 Independent means that a piping or ventingsystem, for example, is in no way connected to anothersystem and that there are no provisions available for thepotential connection to other systems.

1.2.26 Insulation space is the space, which may or maynot be an interbarrier space, occupied wholly or in part byinsulation.

1.2.27 Interbarrier space is the space between a primaryand a secondary barrier, whether or not completely or partiallyoccupied by insulation or other material.

1.2.28 Length, L, in metres, is the length as defined in theInternational Convention on Load Lines.

LR 1.2.3 For the determination of the scantlings for hullconstruction, the Rule length, L, is to be taken as defined in Pt 4, Ch 1,5.

1.2.29 Machinery spaces are all machinery spaces ofcategory A and all other spaces containing propelling machinery, boilers, oil fuel units, steam and internal combus-tion engines, generators and major electrical machinery, oilfilling stations, refrigerating, stabilising, ventilation and airconditioning machinery, and similar spaces and the trunks tosuch spaces.

1.2.30 Machinery spaces of category A are thosespaces, and trunks to those spaces, which contain:

.1 internal combustion machinery used for mainpropulsion for self-propelled units; or

.2 internal combustion machinery used forpurposes where such machinery has in theaggregate a total power output of not less than375 kW; or

.3 any oil-fired boiler or oil fuel unit or any oil-firedequipment other than boilers, such as inert gasgenerators, incinerators, etc.

1.2.31 MARPOL means the International Convention forthe Prevention of Pollution from Ships, 1973, as modified bythe Protocol of 1978 relating thereto, as amended.

1.2.32 MARVS is the maximum allowable relief valvesetting of a cargo tank (gauge pressure).

1.2.33 Non-hazardous area is an area other than ahazardous area.

1.2.34 Oil fuel unit is the equipment used for the prepa-ration of oil fuel for delivery to an oil-fired boiler, or equipmentused for the preparation for delivery of heated oil to an internal combustion engine, and includes any oil pressurepumps, filters and heaters dealing with oil at a pressure ofmore than 1,8 bar gauge.

1.2.35 Organisation is the International MaritimeOrganization (IMO).

1.2.36 Permeability of a space means the ratio of thevolume within that space which is assumed to be occupiedby water to the total volume of that space.

1.2.37 Primary barrier is the inner element designed tocontain the cargo when the cargo containment systemincludes two boundaries.

1.2.38 Products is the collective term used to cover thelist of gases indicated in Chapter 19 of this Part.

1.2.39 Public spaces are those portions of the accom-modation that are used for halls, dining rooms, lounges andsimilar permanently enclosed spaces.

1.2.40 Recognised Organisation is an Organisationauthorised by an Administration in accordance with IMOResolution A.739(18) Guidelines for the Authorisation ofOrganisations acting on Behalf of the Administration, to acton their behalf to survey, certificate and determine tonnagesas required by SOLAS, MARPOL and the Load LineConventions.

1.2.41 Recognised standards are applicable interna-tional or national Standards acceptable to LR.

1.2.42 Relative density is the ratio of the mass of avolume of a product to the mass of an equal volume of freshwater.

1.2.43 Secondary barrier is the liquid-resisting outerelement of a cargo containment system, designed to affordtemporary containment of any envisaged leakage of liquidcargo through the primary barrier and to prevent the loweringof the temperature of the structure of the ship unit to anunsafe level. Types of secondary barrier are more fully definedin Chapter 4.

1.2.44 Separate systems are those cargo piping and ventsystems that are not permanently connected to each other.

1.2.45 Service spaces are those used for galleys,pantries containing cooking appliances, lockers, mail andspecie rooms, storerooms, workshops other than those forming part of the machinery spaces and similar spaces andtrunks to such spaces.

1.2.46 SOLAS Convention means the InternationalConvention for the Safety of Life at Sea, 1974, as amended.

1.2.47 Tank cover is the protective structure intendedeither to protect the cargo containment system againstdamage where it protrudes through the weather deck or toensure the continuity and integrity of the deck structure.

1.2.48 Tank dome is the upward extension of a portion ofa cargo tank. In the case of below deck cargo containmentsystems, the tank dome protrudes through the weather deckor through a tank cover.

1.2.49 Thermal oxidation method means a systemwhere the boil-off vapours are utilised as fuel for shipboarduse or as a waste heat system, subject to the provisions ofChapter 16 or a system not using the gas as fuel complyingwith this Part.




General

1.2.50 Turret compartments are those spaces and trunksthat contain equipment and machinery for retrieval andrelease of the disconnectable turret mooring system, highpressure hydraulic operating systems, fire protection arrange-ments and cargo transfer valves.

1.2.51 Vapour pressure is the equilibrium pressure of thesaturated vapour above the liquid, expressed in bars absolute at a specified temperature.

LR 1.2.4 Design vapour pressure ‘P0’ is the maximumgauge pressure, at the top of the tank, to be used in thedesign of the tank.

1.2.52 Void space is an enclosed space in the cargo areaexternal to a cargo containment system, other than a holdspace, ballast space, oil fuel tank, cargo pumps or compres-sor room, or any space in normal use by personnel.

LR 1.3 Alternative arrangements

LR 1.3.1 Alternative arrangements or fittings which areconsidered to be equivalent to those specified in these Ruleswill be accepted. Arrangements or systems incorporatingfeatures not provided for in these Rules will be speciallyconsidered.

LR 1.4 Survey requirements

LR 1.4.1 Ship units engaged in the production, storageand offloading of liquefied gases are to comply with the surveyrequirements given in Pt 1, Ch 3 and other relevant Parts ofthe Rules.

LR 1.5 Class notations and descriptive notes

LR 1.5.1 The class notations and descriptive notesapplicable to units classed in accordance with these Rulesare to be in accordance with Pt 1, Ch 2 and Pt 3, Ch 3,1, towhich reference should be made.

LR 1.5.2 Where the requirements of this Part arecomplied with, additional class notations in respect of thefollowing items will be assigned as appropriate:• Type of tanks.• Name(s) of gas(es).• Maximum vapour pressure.• Minimum and (where necessary) maximum cargo

temperature.• Design ambient temperatures.

LR 1.5.3 The class notation Lloyd’s RMC(LG) ismandatory when reliquefaction and/or refrigeration equipmentis fitted. The equipment is to be constructed, installed andtested in accordance with the requirements of Chapter 7 andelsewhere in these Rules. The minimum temperature forwhich the installation is suitable will be that given in the mainnotation unless otherwise qualified.SDA, FDA and CM notations are already defined within Part 1and Part 10.

LR 1.6 Information and plans

LR 1.6.1 In addition to the plans required by therelevant Parts of these Rules, the following information andplans are to be submitted, where applicable:• Full particulars of the intended cargo, or cargoes, including

maximum vapour pressures, minimum and (wherenecessary) maximum liquid temperature and other relevant design conditions.

• General arrangement showing location of cargo tanksand the relative location of oil fuel, water ballast andother tanks.

• Openings in main deck.• Location of void spaces and dangerous zones:

openings and access arrangements.• Details of hull structure in way of cargo tanks, including

support arrangements for tanks and associated pipesand fittings, deck sealing arrangements, etc.

• Distribution of quality and grade of steel, supported bycalculations of the determined hull steel temperature.The steel grade and temperature in regions where coldspots are likely to occur (e.g., pump supports and wherepipes pass through the deck) are also to be indicated.

• Scantlings, materials, and arrangements of the cargocontainment system, including primary and (where fitted)secondary barriers, keying and support arrangements,and attachments of fittings, piping, etc.

• Ladders, suction supports and towers inside cargotanks (arrangements, materials and loadings).

• Tank dome plans.• End coamings around dome.• Particulars of filling, discharging, venting, relieving and

inerting arrangements.• Details of test procedures.• Temperature control arrangements.• Such information and data as may be required to enable

analysis of the hull and containment system structure tobe carried out by direct calculation methods.

• Details of personnel protection equipment to be includedon the safety plan as applicable to the ship unit.

• Assumptions and details of direct calculations procedures used in the structural analysis of the hull.

• Where horizontal and vertical girders are used to supportthe bulkhead, the bulkhead scantlings may be deter-mined using direct calculation procedures. Theassumptions made and the calculations are to besubmitted.

The following plans and particulars for Type C independenttanks are to be submitted for approval before construction iscommenced:• Nature of cargoes, together with maximum vapour

pressures and minimum liquid temperature for which thepressure vessels are to be approved, and proposedhydraulic test pressure.

• Particulars of materials proposed for the construction ofthe vessels.

• Particulars of refrigeration equipment.• General arrangement plan showing location of pressure

vessels in the ship unit.• Plans of pressure vessels showing attachments, openings,

dimensions, details of welded joints and particulars ofproposed stress relief heat treatment.

• Plans of seating, securing arrangements and deck sealing arrangements.


Part 11, Chapter 1Sections 2 to 6

LLOYD’S REGISTER4

General

• Plans showing arrangement of mountings, level gaugesand number, type and size of safety valves.

• Details of the arrangements proposed to ensure that thetank or cargo temperature cannot be lowered below theminimum design temperature as defined in 4.1.3.

• Plans showing filling, discharging, venting and inertingpipe arrangements, together with particulars of theintended cargo, maximum vapour pressure and minimumliquid temperature.

• Details of calculations and/or model tests are requiredfor the assessment of the tank boundaries with partialfilling of tanks.

• Allowable stresses of any materials not covered byChapter 6 required by 4.18.1.5.

• Details verifying compliance with the periodical exami-nation of the secondary barrier required by 4.6.2.4 ifapplicable.

• Details of the heating system of the hull structurerequired by 4.19.1.5 if fitted.

• Specification and plans of the containment system areto be submitted for approval. Plans are to include:• Details of insulation material and, if used, any

adhesive, sealers, coatings or similar products.• Details of insulation arrangement.• Internal bearers or steelwork.• Tank supports, chocks, etc.• Hatch trunks.• Attachment and support of insulation and linings.• Data and information to enable a heat leakage

calculation to be carried out to assess the capacityof the arrangements provided to deal with boil-off, including:• Thermal conductivity of insulation between

upper ambient and design temperatures.• Details of reliquefaction/refrigeration plant

duty or maximum allowable boil-off rate foreach cargo.

• The proposed procedure for fabrication, storage,handling, erection, quality control and control againstharmful exposure to sunlight of insulation materials.

• Calculations and/or analysis of strength of insulationwhere it is subjected to high mechanical or thermalloads.

• Fatigue and crack propagation properties for insulationin membrane systems are also to be submitted.

• Specifications of the containment system items are toinclude both those applicable to initial approval of thematerial, and those applicable to subsequent delivery ofbatches of material.

• Plans illustrating the means of protection for the steel-work of the ship unit, e.g., drip trays, cladding, etc., atloading manifolds: deck tanks, cargo handling system,etc.

Additional requirements for information and plans may befound in the appropriate Chapters of this Part.




Document1 12/04/02 15:23 Page 1

Ship Survival Capability and Location of Cargo Tanks

Section

2.1 General

2.2 Freeboard and stability

2.3 Damage assumptions

2.4 Location of cargo tanks

2.5 Flood assumptions

2.6 Standard of damage

2.7 Survival requirements

2.1 General

LR 2.1.1 The requirements of this Chapter, except forrequirement LR 2.1.2 on ship unit type description, are notclassification requirements. However, in cases where LR isrequested to do so by an Owner, Operator or Duty Holder, therequirements of this Chapter will be applied, together with anyamendments or interpretations adopted by the appropriateNational Authority.Reference should be made to the Guidelines for UniformApplication of the Survival Requirements of the Bulk ChemicalCode and the Gas Carrier Code.

2.1.1 Ship units shall survive the hydrostatic effects offlooding following assumed hull damage caused by someexternal force. In addition, to safeguard the ship unit and theenvironment, the cargo tanks shall be protected from penetration in the case of minor damage to the ship unitresulting, for example, from contact with a shuttle tanker,offshore support vessel or tug, by locating them at specifiedminimum distances inboard from the shell plating of the shipunit. Both the damage to be assumed and the proximity ofthe tanks to the shell of the ship unit should be dependentupon the degree of hazard presented by the product to becarried. In addition, the proximity of the cargo tanks to theshell of the ship unit shall be dependent upon the volume ofthe cargo tank.

LR 2.1.2 Ship units subject to this Part shall bedesigned to Type 2G standard. Type 2G is defined as a shipunit intended for the storage of liquefied hydrocarbon gasesas indicated in Chapter 19, that require significant preventivemeasures to preclude their escape.

LR 2.1.3 For the purpose of this Part, the position ofthe moulded line for different containment systems is shownin Figs. 2.1(a) to (e).







LLOYD’S REGISTER2

Detail

Detail

Cargo tank

B.L.

CLM

ould

ed li

ne

Mou

lded

line

Protective distance

B.L.

Moulded line

Moulded line

Pro

tect

ive

dist

ance

Cargo tank shell

Inner bottom

Outer shell (Bottom shell)

CL

Insulation

Insu

latio

n

Car

go ta

nk s

hell

Out

er s

hell

(Sid

e sh

ell)

Fig. 2.1(a) Independent prismatic tank, protective distance





Detail

Detail

Cargo tank

B.L.

CL

Mou

lded

line

Mou

lded

line

Protectivedistance

B.L.

Moulded line

Moulded line

Pro

tect

ive

dist

ance

Inner bottomO

uter

she

ll (S

ide

shel

l)

Inne

r hu

ll (L

ongi

tudi

nal b

ulkh

ead)

Insu

latio

n


Insulation

Fig. 2.1(b) Semi-membrane tank, protective distance




LLOYD’S REGISTER4

Detail

Detail

Cargo tank

B.L.

CL

Mou

lded

line

Mou

lded

line

Protective distance

B.L.

Moulded line

Moulded line

Pro

tect

ive

dist

ance

Inner bottomO

uter

she

ll (S

ide

shel

l)

Inne

r hu

ll

Insu

latio

n


Insulation

CL

Fig. 2.1(c) Membrane tank, protective distance





Mou

lded

line

Mou

lded

line

Protective distance

Moulded line

Pro

tect

ive

dist

ance

Moulded lineDetail

Cargo tank shell

Inner bottom


B.L.

CL

CL

B.L.

Cargo tank

Detail

Car

go ta

nk s

hell

Inne

r hu

ll (L

ongi

tudi

nal b

ulkh

ead)

Out

er s

hell

(Sid

e sh

ell)

Insu

latio

n

Insulation

Fig. 2.1(d) Spherical tank, protective distance


2.2 Freeboard and stability

2.2.1 Ship units subject to this Part may be assigned theminimum freeboard permitted by the International Conventionon Load Lines in force. However, the draught associated withthe assignment shall not be greater than the maximumdraught otherwise permitted by these Rules.

2.2.2 The stability of the ship unit, in all sea-going condi-tions including inspection/maintenance, ballasting and duringloading and unloading cargo, shall comply with the require-ments of the International Code on Intact Stability.


Part 11, Chapter 2Sections 1 & 2

LLOYD’S REGISTER6

Cargo tank

B.L.

Detail

CL

Detail

Car

go ta

nk s

hell

Out

er s

hell

(Sid

e sh

ell)

Mou

lded

line

Mou

lded

line

Protectivedistance

Moulded line

Moulded line

Pro

tect

ive

dist

ance

B.L.

CL


Cargo tank shell

Fig. 2.1(e) Pressure type tank, protective distance


2.2.3 When calculating the effect of free surfaces ofconsumable liquids for loading conditions, it shall be assumedthat, for each type of liquid, at least one transverse pair or asingle centre tank has a free surface. The tank or combina-tion of tanks to be taken into account shall be those wherethe effect of free surfaces is the greatest. The free surfaceeffect in undamaged compartments shall be calculated by amethod according to the International Code on Intact Stability.

2.2.4 Solid ballast should not normally be used in doublebottom spaces in the cargo area. Where, however, becauseof stability considerations, the fitting of solid ballast in suchspaces becomes unavoidable, its disposition shall begoverned by the need to enable access for inspection and toensure that the impact loads resulting from bottom damageare not directly transmitted to the cargo tank structure.

2.2.5 The Operator of the ship unit shall be supplied witha loading and stability information booklet. This booklet shallcontain details of typical service and inspection/maintenanceconditions, loading, unloading and ballasting operations,provisions for evaluating other conditions of loading and asummary of the survival capabilities of the ship unit. In addition, the booklet shall contain sufficient information toenable the Operator to load and operate the ship unit in a safeand seaworthy manner. See also Pt 1, Ch 2 and Pt 10, Ch 3,1.2.In addition, the Operator is to be given an approved stabilityinstrument to assess the intact stability and the damagestability condition according to the standard damage casesand the actual damage condition of the ship unit. The stabilityinstrument input data and output results have to be approvedby the Administration.

2.2.6 Damage survival capability shall be investigated onthe basis of loading information submitted to the Admini -stration for all anticipated conditions of loading and variationsin draught and trim. This shall include ballast and, whereapplicable, cargo heel.

2.3 Damage assumptions

2.3.1 The assumed maximum extent of damage shall beas shown in Table 2.3.1.

2.3.2 Other damage

2.3.2.1 If any damage of a lesser extent than the maximumdamage specified in Table 2.3.1 would result in a more severecondition, such damage should be assumed.

2.3.2.2 Local damage anywhere in the cargo area extendinginboard distance ‘d’ as defined in 2.4.1, measured normal tothe moulded line of the outer shell shall be considered.Bulkheads shall be assumed damaged, see 2.6.1. If adamage of a lesser extent than ‘d’ would result in a moresevere condition, such damage shall be assumed.




Location of damage Assumed maximum extent of damage

1. Side damage To any part of the ship unit

1.1 Longitudinal extent 1/3L2/3 or 14,5 m, whichever is less

1.2 Transverse extent measured B/5 or 11,5 m, whichever is lessinboard from the moulded line of the outer shell at right angles to the centreline at the level of the summer load line

1.3 Vertical extent from the Upwards, without limitmoulded line of the outer shell at right angles to the centreline atthe level of the summer load line

2. Bottom damage For 0,3L from the forward perpendicular of the To any other part of the ship unitship unit

2.1 Longitudinal extent 1/3L2/3 or 14,5 m, whichever is less 1/3L2/3 or 14,5 m, whichever is less

2.2 Transverse extent B/6 or 10 m, whichever is less B/6 or 5 m, whichever is less

2.3 Vertical extent B/15 or 2 m, whichever is less measured from B/15 or 2 m, whichever is less measured fromthe moulded line of the bottom shell plating at the moulded line of the bottom shell plating atcentreline, see 2.4.3 centreline, see 2.4.3

Table 2.3.1 Assumed maximum extent of damage


2.4 Location of cargo tanks

2.4.1 Cargo tanks shall be located at the followingdistances inboard:Type 2G ship unit: from the moulded line of the bottom shellat centreline not less than the vertical extent of damage specified in 2.3 in Table 2.3.1 and nowhere less than ‘d’ (seeFigs. 2.2 and 2.3), where ‘d’ is as follows:(i) for Vc below or equal to 1000 m3, d = 0,80 m(ii) for 1000 m3 < Vc < 5000 m3,

d = 0,75 + Vc × 0,20/4000(iii) for 5000 m3 ≤ Vc < 30 000 m3,

d = 0,8 + Vc/25 000(iv) for Vc ≥ 30 000 m3, d = 2 m,whereVc corresponds to 100 per cent of the gross design volume ofthe individual cargo tank at 20°C, including domes andappendages. For the purpose of cargo tank protectivedistances, the cargo tank volume is the aggregate volume ofall the parts of tank that have a common bulkhead(s).NOTE

‘d’ is measured at any cross-section at a right angle from themoulded line of outer shell.

2.4.2 For the purpose of tank location, the vertical extentof bottom damage shall be measured to the inner bottomwhen membrane or semi membrane tanks are used, other-wise to the bottom of the cargo tanks. The transverse extentof side damage shall be measured to the longitudinal bulk-head when membrane or semi membrane tanks are used,otherwise to the side of the cargo tanks. The distances indicated in 2.3 and 2.4 shall be applied as in Figs. 2.1(a) to(e). These distances shall be measured plate to plate, fromthe moulded line to the moulded line, excluding insulation.

2.4.3 Suction wells installed in cargo tanks may protrudeinto the vertical extent of bottom damage specified in 2.3 inTable 2.3.1 provided that such wells are as small as practicableand the protrusion below the inner bottom plating does notexceed 25 per cent of the depth of the double bottom or 350 mm, whichever is less. Where there is no double bottom,the protrusion below the upper limit of bottom damage shallnot exceed 350 mm. Suction wells installed in accordancewith this paragraph may be ignored when determining thecompartments affected by damage.

LR 2.4.1 Cargo tanks shall not be located forward ofthe collision bulkhead.

LR 2.4.2 When more than one independent tank isfitted in a space, sufficient clearance is to be left between thetanks for inspection or repairs.



LLOYD’S REGISTER8

B.L.

Collision bulkheadA

A

B

B

Vertical extent of bottom damagespecified in 2.3 in Table 2.3.1

Distance, d,specified in 2.4.1

Type 2G ship unit


or Distance, d, specified in 2.4.1

whichever is greater

Area where cargo tankmay not be located

Fig. 2.2 Cargo tank location requirements, centreline profile, Type 2G ship units


2.5 Flood assumptions

2.5.1 The requirements of 2.7 shall be confirmed bycalculations that take into consideration the design charac-teristics of the ship unit, the arrangements, configuration andcontents of the damaged compartments, the distribution,relative densities and the free surface effects of liquids andthe draught and trim for all conditions of loading.

2.5.2 The permeability of spaces assumed to bedamaged shall be as given in Table 2.5.1.

2.5.3 Wherever damage penetrates a tank containingliquids, it shall be assumed that the contents are completelylost from that compartment and replaced by saltwater up tothe level of the final plane of equilibrium.

2.5.4 The ship unit shall be designed to keep unsym-metrical flooding to the minimum consistent with efficientarrangements.

2.5.5 Equalisation arrangements requiring mechanicalaids such as valves or cross-levelling pipes, if fitted, shall notbe considered for the purpose of reducing an angle of heel orattaining the minimum range of residual stability to meet therequirements of 2.7.1 and sufficient residual stability shall bemaintained during all stages where equalisation is used.Spaces linked by ducts of large cross-sectional area may beconsidered to be common.

2.5.6 If pipes, ducts, trunks or tunnels are situated withinthe assumed extent of damage penetration, as defined in 2.3,arrangements shall be such that progressive flooding cannotthereby extend to compartments other than those assumedto be flooded for each case of damage.




Table 2.5.1 Permeability of spaces assumed to bedamaged

Space Permeability

Stores 0,6Accommodation 0,95Machinery 0,85Voids 0,95Hold spaces 0,95 see Note 1Consumable liquids 0 to 0,95 see Note 2Other liquids 0 to 0,95 see Note 2

NOTES1. Other values of permeability can be considered based on

detailed calculations; refer to MSC/Circ.651 Interpretations ofpart B-1 of SOLAS Chapter II-1.

2. The permeability of partially filled compartments shall beconsistent with the amount of liquid carried in the compart-ment.

Area where cargo tankmay not be located


Vertical extent of bottomdamage specified in 2.3 in Table 2.3.1

orDistance, d, specified in 2.4.1

whichever is greater

Section A-Asee Fig. 2.3

Section B-Bsee Fig. 2.2

Summerload line

B.L.

CL


Summerload line

B.L.

CL


Fig. 2.3 Cargo tank location requirements, transverse sections, Type 2G ship units


2.5.7 The buoyancy of any superstructure directly abovethe side damage shall be disregarded. However, theunflooded parts of superstructures beyond the extent ofdamage may be taken into consideration provided that:

.1 they are separated from the damaged space bywatertight divisions and the requirements of2.7.1.1 in respect of these intact spaces arecomplied with; and

.2 openings in such divisions are capable of beingclosed by remotely operated sliding watertightdoors and unprotected openings are notimmersed within the minimum range of residualstability required in 2.7.2.1. However, the immersion of any other openings capable ofbeing closed weathertight may be permitted.

2.6 Standard of damage

2.6.1 Type 2G ship units shall be capable of surviving thedamage indicated in 2.3 anywhere in its length with the flooding assumptions in 2.5.

2.7 Survival requirements

Ship units shall be capable of surviving the assumed damagespecified in 2.3, to the standard provided in 2.6, in a conditionof stable equilibrium and shall satisfy the following criteria.

2.7.1 In any stage of flooding:.1 the waterline, taking into account sinkage, heel

and trim, shall be below the lower edge of anyopening through which progressive flooding ordownflooding may take place. Such openingsshall include air pipes and openings that areclosed by means of weathertight doors or hatchcovers and may exclude those openings closedby means of watertight manhole covers andwatertight flush scuttles, small watertight cargotank hatch covers that maintain the high integrityof the deck, remotely operated watertight slidingdoors and sidescuttles of the non opening type;

.2 the maximum angle of heel due to unsymmetricalflooding shall not exceed 30°; and

.3 the residual stability during intermediate stagesof flooding shall not be significantly less than thatrequired by 2.7.2.1.

2.7.2 At final equilibrium after flooding:.1 the righting lever curve shall have a minimum

range of 20° beyond the position of equilibriumin association with a maximum residual rightinglever of at least 0,1 m within the 20° range; thearea under the curve within this range shall notbe less than 0,0175 m radians. The 20° rangemay be measured from any angle commencingbetween the position of equilibrium and the angleof 25° (or 30° if no deck immersion occurs).Unprotected openings shall not be immersedwithin this range unless the space concerned isassumed to be flooded. Within this range, theimmersion of any of the openings listed in 2.7.1.1and other openings capable of being closedweathertight may be permitted; and

.2 the emergency source of power shall be capableof operating.


Part 11, Chapter 2Sections 5, 6 & 7

LLOYD’S REGISTER10

Ship Arrangements

Section

3.1 Segregation of the cargo area and cargo tankholds

3.2 Accommodation, service and machinery spacesand control stations

3.3 Cargo machinery spaces and turretcompartments

3.4 Cargo control rooms

3.5 Access to spaces in the cargo area

3.6 Airlocks

3.7 Bilge, ballast and oil fuel arrangements

3.8 Tandem and side-by-side loading and unloadingarrangements

3.1 Segregation of the cargo area and cargo tankholds

LR 3.1.1 In addition to the requirements outlined in thisSection, the requirements of Pt 3, Ch 2 are to be compliedwith.

3.1.1 Hold spaces shall be segregated from machineryand boiler spaces, accommodation spaces, service spaces,control stations, chain lockers, domestic water tanks andfrom stores. Hold spaces shall be located forward of machineryspaces of category A. Alternative arrangements, includinglocating machinery spaces of category A forward, may beaccepted, based on SOLAS, Regulation 17, after furtherconsideration of involved risks, including that of cargo releaseand the means of mitigation.

3.1.2 Where cargo is carried in a cargo containmentsystem not requiring a complete or partial secondary barrier,segregation of hold spaces from spaces referred to in 3.1.1 orspaces either below or outboard of the hold spaces may beeffected by cofferdams, oil fuel tanks or a single gastight bulk-head of all-welded construction forming an A-60 classdivision. A gastight A-0 class division is acceptable if there isno source of ignition or fire hazard in the adjoining spaces.

3.1.3 Where cargo is carried in a cargo containmentsystem requiring a complete or partial secondary barrier,segregation of hold spaces from spaces referred to in 3.1.1,or spaces either below or outboard of the hold spaces thatcontain a source of ignition or fire hazard, shall be effected bycofferdams or oil fuel tanks. A gastight A-0 class division isacceptable if there is no source of ignition or fire hazard in theadjoining spaces.

3.1.4 Segregation of turret compartments from spacesreferred to in 3.1.1, or spaces either below or outboard of theturret compartment that contain a source of ignition or firehazard, shall be effected by cofferdams or an A-60 class division. A gastight A-0 class division is acceptable if there isno source of ignition or fire hazard in the adjoining spaces.

3.1.5 In addition, the risk of fire propagation from turretcompartments to adjacent spaces shall be evaluated by a riskanalysis, see Chapter 1 and Pt 1, Ch 5, and further preventivemeasures, such as the arrangement of a cofferdam aroundthe turret compartment, shall be provided if needed.

3.1.6 When cargo is carried in a cargo containmentsystem requiring a complete or partial secondary barrier:

.1 at temperatures below –10°C, hold spaces shallbe segregated from the sea by a double bottom;and

.2 at temperatures below –55°C, the ship unit shallalso have a longitudinal bulkhead forming sidetanks.

3.1.7 Arrangements shall be made for sealing the weatherdecks in way of openings for cargo containment systems.

LR 3.1.2 Cargo tank holds are to be separated fromeach other by single bulkheads of all welded construction.Where, however, the design temperature as defined inChapter 4 is below –55°C, cofferdams are to be adoptedunless the cargo is carried in independent tanks andalternative arrangements are made to ensure the bulkheadcannot be cooled to below –55°C. Cofferdams may be usedas ballast tanks, subject to approval by Lloyd’s Register (LR).

3.2 Accommodation, service and machineryspaces and control stations

3.2.1 No accommodation space, service space (exceptcargo service spaces, see LR 3.2.1 or topsides servicespaces) or control station shall be located within the cargoarea. The bulkhead of accommodation spaces, servicespaces (except cargo and topsides service spaces) or controlstations that face the cargo area shall be so located as toavoid the entry of gas from the hold space to such spacesthrough a single failure of a deck or bulkhead on a ship unithaving a containment system requiring a secondary barrier.Cargo, topsides and turret service spaces (i.e. workshops,store rooms, etc.) and machinery spaces located above thecargo storage areas, which are impacted by hazardous areas,are to be in accordance with the requirements of Pt 7, Ch 2,4.

LR 3.2.1 Cargo service spaces as defined in Ch 1,1.2may be situated within cargo areas, provided all other relevantrequirements of these Rules are complied with.




Ship Arrangements

3.2.2 In order to guard against the danger of hazardousvapours, due consideration should be given to the location ofair intakes/outlets and openings into accommodation, serviceand machinery spaces and control stations in relation tocargo piping, cargo vent systems and machinery spaceexhausts from gas burning arrangements. See Pt 7, Ch 2,regarding the air intakes/outlets and openings to enclosednon hazardous areas.

3.2.3 As far as practicable, access doors or other openings should not be provided between a non-hazardousspace and a hazardous area or space, or between Zone 2and a Zone 1 space, as defined in Chapter 10. Where suchopenings are necessary, access from the accommodation,service spaces, machinery spaces or any other defined nonhazardous enclosed areas on topsides, deck, turret or withinthe hull are to be in compliance with Pt 7, Ch 2,4.

3.2.4 Entrances, air inlets and openings to accommoda-tion spaces and hull spaces and control stations shall not facethe cargo area. They shall be located on the end bulkheadnot facing the cargo area or on the outboard side of thesuperstructure or deckhouse or on both at a distance of atleast 4 per cent of the load line length, L, as defined in 1.2 ofthe ship unit but not less than 3 m from the end of the super-structure or deckhouse facing the cargo area. This distance,however, need not exceed 5 m.

.1 Windows and sidescuttles facing the cargo areaand on the sides of the superstructures or deck-houses within the distance mentioned aboveshall be of the fixed (non-opening) type.Wheelhouse windows for navigational purposesmay be non-fixed and wheelhouse doors may belocated within the above limits so long as they aredesigned in a manner such that a rapid and efficient gas and vapour tightening of the wheel-house can be ensured.

.2 Access to forecastle spaces containing sourcesof ignition may be permitted through door accessfacing the cargo area, provided the doors areeither located a suitable distance outsidehazardous areas as defined in Chapter 10 or arein accordance with the requirements of Pt 7, Ch 2,4.

3.2.5 Windows and sidescuttles facing the cargo areaand on the sides of the superstructures and deckhouseswithin the limits specified in 3.2.4, except wheelhousewindows for navigational purposes where applicable, shall beconstructed to at least A-60 class. Wheelhouse windows fornavigational purposes shall be constructed to at leastA-0 class (for external fire load). Sidescuttles in the shell belowthe uppermost continuous deck and in the first tier of thesuperstructure or deckhouse shall be of fixed (non-opening)type. It should be noted that the above minimum class ofwindows should be confirmed for their suitability within theinstallation Fire and Explosion Evaluation (FEE). If necessary,higher rated windows or alternative designs without windowsmay be required dependent upon the findings of the FEE.

3.2.6 All air intakes, outlets and other openings into theaccommodation spaces, service spaces and control stationsshall be fitted with closing devices. For toxic gases, they shallbe operated from inside the space. Air intakes and outlets andthe protection against gas ingress into all accommodationspaces, service spaces and control stations are to be inaccordance with the requirements of Pt 7, Ch 1,5 and Pt 7,Ch 2,6.1.3.

3.2.7 Control rooms and machinery spaces of turretsystems may be located in the cargo area forward or aft ofcargo tanks in ship units with such installations. Access tosuch spaces containing sources of ignition may be permittedthrough doors facing the cargo area, provided the doors arelocated outside hazardous areas or access is in accordancewith the requirements of Pt 7, Ch 2,4.

LR 3.2.2 Any topsides or turret service spaces ormachinery spaces shall generally be treated for the purpose offire containment according to SOLAS Regulation II-2/9.2.4.However, alternative fire protection and fire mitigatingmeasures may be considered to be appropriate followingassessment via the installation Fire and Explosion Evaluation(FEE), dependent upon the installation’s fire-fighting andsafety philosophy.

LR 3.2.3 Arrangements of any topsides or turret servicespaces or machinery spaces should ensure safe unrestrictedaccess for personnel wearing protective clothing and breathing apparatus, and in the event of injury to allow unconscious personnel to be removed. At least two widelyseparated escape routes and doors shall be provided in eachservice space, except that a single escape route may beaccepted where the maximum travel distance to the door is 5 m or less.

3.3 Cargo machinery spaces and turretcompartments

3.3.1 Cargo machinery spaces shall be situated abovethe weather deck and located within the cargo area. Cargomachinery spaces and turret compartments shall be treatedas cargo pump rooms for the purpose of fire protectionaccording to SOLAS Regulation II-2/9.2.4, and for thepurpose of prevention of potential explosion according toSOLAS ll-2/ 4.5.10.

3.3.2 When cargo machinery spaces are located at theafter end of the aftermost hold space or at the forward end ofthe forwardmost hold space, the limits of the cargo area, asdefined in 1.2, shall be extended to include the cargo machinery spaces for the full breadth and depth of the shipunit and the deck areas above those spaces.

3.3.3 Where the limits of the cargo area are extended by3.3.2, the bulkhead that separates the cargo machineryspaces from accommodation and service spaces, controlstations and machinery spaces of category A shall be locatedso as to avoid the entry of gas to these spaces through asingle failure of a deck or bulkhead.



LLOYD’S REGISTER2

Ship Arrangements

3.3.4 Cargo compressors and cargo pumps may bedriven by electric motors in an adjacent non-hazardous spaceseparated by a bulkhead or deck if the seal around the bulk-head penetration ensures effective gas-tight segregation ofthe two spaces. Alternatively such equipment may be drivenby certified safe electric motors adjacent to them if the electrical installation complies with the requirements ofChapter 10.

3.3.5 Arrangements of cargo machinery spaces andturret compartments should ensure safe unrestricted accessfor personnel wearing protective clothing and breathing apparatus, and in the event of injury to allow unconsciouspersonnel to be removed. At least two widely separatedescape routes and doors shall be provided in cargo machineryspaces, except that a single escape route may be acceptedwhere the maximum travel distance to the door is 5 m or less.

3.3.6 All valves necessary for cargo handling shall bereadily accessible to personnel wearing protective clothing.Suitable arrangements shall be made to deal with drainage ofpump and compressor rooms.

3.3.7 Turret compartments shall be designed to retaintheir structural integrity in case of explosion or uncontrolledhigh pressure gas release (overpressure and/or brittle fracture), the characteristics of which shall be substantiatedon the basis of a risk analysis with due consideration of thecapabilities of the pressure-relieving devices. See also Pt 10,Ch 2,5.2.

3.4 Cargo control rooms

3.4.1 Any cargo control room shall be above the weatherdeck and may be located in the cargo area. The cargo controlroom may be located within the accommodation spaces,service spaces or control stations provided the followingconditions are complied with:

.1 the cargo control room is a non-hazardous area;

.2.1 if the entrance complies with 3.2.4, the controlroom may have access to the spaces describedabove;

.2.2 if the entrance does not comply with 3.2.4 thecargo control room shall have no access to thespaces described above and the boundaries forsuch spaces shall be insulated to at leastA-60 class or higher. It should be noted that the minimum fire class of a cargo control room’sboundaries should be confirmed for their suitability within the installation Fire and ExplosionEvaluation (FEE). If necessary, higher rated fireboundaries may be required, dependent uponthe findings of the FEE.

3.4.2 If the cargo control room is designed to be a non-hazardous area, instrumentation should, as far as possible,be by indirect reading systems and shall in any case bedesigned to prevent any escape of gas into the atmosphere ofthat space. Location of the gas detection system within thecargo control room will not cause the room to be classified asa hazardous area, if installed in accordance with 13,6.9.

3.4.3 If the cargo control room for ship units carryingflammable cargoes is classified as a hazardous area, sourcesof ignition shall be excluded and any electrical equipment shallbe installed in accordance with Chapter 10.

3.5 Access to spaces in the cargo area

3.5.1 Visual inspection of at least one side of the innerhull structure shall be possible without the removal of anyfixed structure or fitting. If such a visual inspection, whether ornot combined with those inspections required in 3.5.2 orChapter 4, is only possible at the outer face of the inner hull,the inner hull shall not be a fuel oil tank boundary wall.

3.5.2 Inspection of one side of any insulation in holdspaces shall be possible. If the integrity of the insulationsystem can be verified by inspection of the outside of the holdspace boundary when tanks are at service temperature,inspection of one side of the insulation in the hold space neednot be required.

3.5.3 Arrangements for hold spaces, void spaces, cargotanks and other spaces defined as hazardous areas inChapter 10, shall be such as to allow entry and inspection ofany such space by personnel wearing protective clothing andbreathing apparatus and shall also allow for the evacuation ofinjured and/or unconscious personnel. Such arrangementsshall comply with the following:

.1 Access shall be provided:

.1.1 To all cargo tanks, access shall be direct from theweather deck.

.1.2 Access through horizontal openings¸ hatches ormanholes, the dimensions shall be sufficient toallow a person wearing a breathing apparatus toascend or descend any ladder without obstruc-tion and also to provide a clear opening tofacilitate the hoisting of an injured person fromthe bottom of the space the minimum clear opening shall be not less than 600 mm × 600 mm;and

.1.3 Access through vertical openings or manholesproviding passage through the length andbreadth of the space, the minimum clear openingshall be not less than 600 mm x 800 mm at aheight of not more than 600 mm from the bottomplating unless gratings or other footholds areprovided.

.1.4 Circular access openings to Type C tanks shallhave a diameter of not less than 600 mm.

.2 The dimensions referred to in 3.5.3.1.2 and3.5.3.1.3 may be decreased if the requirementsof 3.5.3 can be met to the satisfaction of theAdministration.

.3 Where cargo is carried in a containment systemrequiring a secondary barrier the requirements of3.5.3.1.2 and 3.5.3.1.3 do not apply to spacesseparated from a hold space by a single gastightsteel boundary. Such spaces shall be providedonly with direct or indirect access from theweather deck, not including any enclosed nonhazardous area.




.4 Access required for inspection shall be providedas follows:

.4.1 Designated access through structures below andabove cargo tanks shall have at least the crosssections as required by 3.5.3.1.3

.5 For the purpose of 3.5.1 or 3.5.2 the followingshall apply:

.5.1 Where it is required to pass between the surfaceto be inspected, flat or curved, and structuressuch as deck beams, stiffeners, frames, girders,etc., the distance between that surface and thefree edge of the structural elements shall be atleast 380 mm. The distance between the surfaceto be inspected and the surface to which theabove structural elements are fitted, e.g. deck,bulkhead or shell, shall be at least 450 mm for acurved tank surface (e.g. for a Type C tank) or600 mm for a flat tank surface (e.g. for a Type Atank). (See Fig. 3.1).

Ship Arrangements

.5.2 Where it is not required to pass between thesurface to be inspected and any part of the structure, for visibility reasons the distancebetween the free edge of that structural elementand the surface to be inspected shall be at least50 mm or half the breadth of the face plate of the structure, whichever is the larger. See Fig. 3.2.

.5.3 For inspection of a curved surface where it isrequired to pass between that surface andanother surface, flat or curved, to which no structural elements are fitted, the distancebetween both surfaces shall be at least 380 mm,see Fig. 3.3. Where it is not required to passbetween that curved surface and anothersurface, a smaller distance than 380 mm may beaccepted taking into account the shape of thecurved surface.



LLOYD’S REGISTER4

Cargo tank380

380

Flat surface ofship structure

Fig. 3.3 Minimum passage clearance for tank inspection between surfaces

Passage

Ship structure

600/

450

380

Cargo tank b/2 or 50 whichever is greater

b

Fig. 3.2Minimum visibility clearance for tank

inspection in way of ship structural members

Passage

Ship structure

600/

450

380

Cargo tank

Fig. 3.1Minimum passage clearance for tank inspection in

way of ship structural members

Ship Arrangements

.5.4 For inspection of an approximately flat surfacewhere it is required to pass between two approximately flat and approximately parallelsurfaces, to which no structural elements arefitted, the distance between those surfaces shallbe at least 600 mm. Where fixed access laddersare fitted a clearance of at least 450 mm shall beprovided for access. See Fig. 3.4.

.5.5 The minimum distances between a cargo tanksump and adjacent double bottom structure inway of a suction well shall not be less than thoseshown in Fig. 3.5. If there is no suction well thedistance between the cargo tank sump and theinner bottom shall not be less than 50 mm.NOTE

Fig. 3.5 shows that the distance between theplane surfaces of the sump and the well is a minimum of 150 mm and that the clearancebetween the edge between the inner bottomplate, and the vertical side of the well and theknuckle point between the spherical or circularsurface and sump of the tank is at least 380 mm.

.5.6 The distance between a cargo tank dome anddeck structures shall not be less than 150 mm.See Fig. 3.6.

.5.7 Fixed or portable staging shall be installed asnecessary for inspection of cargo tanks, cargotank supports and restraints (e.g. anti-pitching,anti-rolling and anti-flotation chocks), cargo tankinsulation etc. This staging shall not impair theclearances specified in 3.5.3.5.1 to 3.5.3.5.4.

.5.8 If fixed or portable ventilation ducting is to befitted in compliance with 12.2, such ducting shallnot impair the distances required under 3.5.3.5.1to 3.5.3.5.4.

LR 3.5.1 In general, the requirements for minimum clearopening given in 3.5.3.1.2 and 3.5.3.1.3 are also to beadhered to for spaces separated by a single gastight steelboundary from a hold space where cargo is carried in a cargocontainment system requiring a secondary barrier. Referenceis made to IACS Interpretations of the IMO Code for theConstruction and Equipment of Ships carrying LiquefiedGases in Bulk No. GC6.For ship units complying with the requirements for Type Aindependent tanks, manholes will not be permitted throughthe secondary barrier, except through the upper deck inregions which are above the predicted surface of the cargoassuming total failure of the cargo tank and the ship unit at30 degrees heel port or starboard. Alternative structuralarrangement will be specially considered.

3.5.4 As far as practicable, access from the openweather deck to non-hazardous areas are to be locatedoutside hazardous areas as defined in Chapter 10. Where it isnot possible to located a weather deck non hazardous enclosure access doorway in a non hazardous area, access isto be in compliance with Pt 7, Ch 2,4.




600

600 450

Step ofaccessladder

Flatsurfaceof tank

Flat surface of ship structure

Fig. 3.4 Minimum access clearance in way of fixed access ladders

Ship Arrangements

3.5.5 Turret compartments shall be arranged with twoindependent means of access/egress. The access/egressroutes are to ensure safe unrestricted access for personnelwearing protective clothing and breathing apparatus, and inthe event of injury to allow unconscious personnel to beremoved. A single escape route may be accepted for turretcompartments where the maximum travel distance to thedoor is 5 m or less.

3.5.6 Access from a hazardous area below the hullweather deck to a non-hazardous area should be avoided.However, where it is not practicable access is to be in compliance with Pt 7, Ch 2,4.



LLOYD’S REGISTER6

150

Deck structure

Fig. 3.6 Minimum distance between cargo tank dome and deck structure

150

150

380

Inner bottom

Fig. 3.5Minimum distances between cargo tank sump and adjacent double bottom structure in way of a section well

Ship Arrangements

3.6 Airlocks

3.6.1 Access between hazardous areas on the openweather deck and non-hazardous spaces shall be by meansof an airlock. This shall consist of two self closing, substan-tially gastight, steel doors without any holding backarrangements, capable of maintaining the over pressure, atleast 1,5 m but no more than 2,5 m apart. The airlock spaceshall be artificially ventilated from a non-hazardous area andmaintained at an overpressure to the hazardous area on theweather deck.

3.6.2 Where spaces are protected by pressurisation, theventilation is to be designed and installed in accordance withPt 7, Ch 1,5 and Pt 7, Ch 2,6.1.3 or an equivalent National orInternationally recognised Standard, submitted to LR forapproval.

3.6.3 The relative air pressure within the non hazardousenclosure is to be continuously monitored and so arranged that,in the event of loss of overpressure, an alarm is given at amanned control station.

3.6.4 For electrical equipment that is located in enclosednon hazardous spaces, is not certified for operation in a Zone1 hazardous area and does not have to remain operationalduring catastrophic conditions (i.e., major hydrocarbonrelease scenarios), consideration shall be given to de-energisingthis equipment in case of confirmed loss of overpressure inthe space. If the flammable gas is subsequently detectedwithin the area all non emergency electrical items of equip-ment are to be de-energised immediately.

3.6.5 Electrical equipment for manoeuvring, anchoringand mooring as well as emergency fire pumps that arelocated in spaces protected by airlocks shall be of a certifiedsafe type.

3.6.6 The airlock space shall be monitored for cargovapours, see also 13.6.2.

3.6.7 Subject to the requirements of the InternationalConvention on Load Lines as amended, the door sill shall notbe less than 300 mm in height.

LR 3.6.1 Air locks are to ensure safe unrestricted accessfor personnel wearing protective clothing and breathing apparatus, and in the event of injury to allow unconsciouspersonnel to be removed.

3.7 Bilge, ballast and oil fuel arrangements

3.7.1 Where cargo is carried in a cargo containmentsystem not requiring a secondary barrier, suitable drainagearrangements for the hold spaces that are not connected withthe machinery space shall be provided. Means of detectingany leakage shall be provided.

3.7.2 Where there is a secondary barrier, suitabledrainage arrangements for dealing with any leakage into thehold or insulation spaces through the adjacent ship structureshall be provided. The suction shall not lead to pumps insidethe machinery space. Means of detecting such leakage shallbe provided.

3.7.3 The hold or interbarrier spaces of Type A indepen-dent tank ship units shall be provided with a drainage systemsuitable for handling liquid cargo in the event of cargo tankleakage or rupture. Such arrangements shall provide for thereturn of any cargo leakage to the liquid cargo piping.

3.7.4 Arrangements referred to in 3.7.3 shall be providedwith a removable spool piece.

3.7.5 Ballast spaces, including wet duct keels used asballast piping, fuel oil tanks and non-hazardous spaces, maybe connected to pumps in the machinery spaces. Dry ductkeels with ballast piping passing through may be connectedto pumps in the machinery spaces, provided the connectionsare led directly to the pumps and the discharge from thepumps is led directly overboard with no valves or manifoldsin either line that could connect the line from the duct keel tolines serving non-hazardous spaces. Pump vents shall not beopen to machinery spaces.

3.8 Tandem and side-by-side loading andunloading arrangements

3.8.1 Subject to the requirements of this Section andChapter 5, cargo piping may be arranged to permit tandem(bow or stern) and side-by-side loading and unloading.

3.8.2 Portable arrangements shall not be permitted.

3.8.3 Entrances, air inlets and openings to accommoda-tion spaces, service spaces, machinery spaces and controlsstations shall not face the cargo connection location of theunloading arrangements. They shall be located on theoutboard side of the superstructure or deckhouse at adistance of at least 4 per cent of the length of the ship unit,but not less than 3 m from the end of the superstructure ordeckhouse facing the cargo connection location of theunloading arrangements. This distance need not exceed 5 m.

.1 Windows and sidescuttles facing the connectionlocation of the shuttle tanker and on the sides ofthe superstructure or deckhouse within thedistance mentioned above shall be of the fixed(non-opening) type.

.2 In addition, during the use of the unloadingarrangements, all doors, ports and other openingson the corresponding superstructure or deck-house side should be kept closed.

3.8.4 Deck openings and air inlets and outlets to spaceswithin distances of 10 m from the cargo shore connectionlocation shall be kept closed during the use of the unloadingarrangements.




Ship Arrangements

3.8.5 Fire-fighting arrangements for the unloading areasshall generally be in accordance with 11.3.1.4 and 11.4.However, alternative fire protection and fire mitigatingmeasures may be considered to be appropriate followingassessment via the installation Fire and Explosion Evaluation(FEE), dependent upon the installation’s fire-fighting andsafety philosophy. Full details of the proposals are to besubmitted for consideration.

3.8.6 Means of communication between the cargocontrol station and the connection location of the shuttletanker shall be provided and where applicable certified for usein hazardous areas.

LR 3.8.1 Hull, hull weather deck and liquefied gasoffloading arrangements shall generally be treated for thepurpose of fire containment according to SOLAS RegulationII-2/9.2.4 and for fire mitigation according to Pt 11, Ch 11.However, alternative fire protection and fire mitigatingmeasures may be considered to be appropriate followingassessment via the installation Fire and Explosion Evaluation(FEE), dependent upon the installation’s fire-fighting andsafety philosophy.



LLOYD’S REGISTER8

Cargo Containment

Section

4.1 Definitions

4.2 Application

Part A Cargo containment

4.3 Functional requirements

4.4 Cargo containment safety principles

4.5 Secondary barriers in relation to tank types

4.6 Design of secondary barriers

4.7 Partial secondary barriers and primary barriersmall leak protection system

4.8 Supporting arrangements

4.9 Associated structure and equipment

4.10 Thermal insulation

Part B Design loads

4.11 General

4.12 Permanent loads

4.13 Functional loads

4.14 Environmental loads

4.15 Accidental loads

Part C Structural integrity

4.16 General

4.17 Structural analyses

4.18 Design conditions

Part D Materials and construction

4.19 Materials

4.20 Construction processes

Part E Tank types

4.21 Type A independent tanks

4.22 Type B independent tanks

4.23 Type C independent tanks

4.24 Membrane tanks

4.25 Integral tanks

4.26 Semi-membrane tanks

Part F Guidance

4.27 Guidance Notes for Chapter 4

4.1 Definitions

4.1.1 Cold spot. A cold spot is a part of the hull or thermalinsulation surface where a localised temperature decreaseoccurs under loaded condition with respect to the allowableminimum temperature of the hull or of its adjacent hull structure, or to design capabilities of cargo pressure/temperature control systems required in Chapter 7.

4.1.2 Design vapour pressure. The design vapour pres-sure ‘Po’ is the maximum gauge pressure, at the top of thetank, to be used in the design of the tank.

4.1.3 Design temperature. The design temperature forselection of materials is the minimum temperature at whichcargo may be loaded or stored in the cargo tanks.

4.1.4 Independent tanks are self-supporting; they donot form part of the hull of the ship unit and are not essentialto the hull strength. There are three categories of independenttank, which are referred to in 4.21, 4.22 and 4.23.

4.1.5 Membrane tanks are non-self-supporting tanksthat consist of a thin liquid and gas tight layer (membrane)supported through insulation by the adjacent hull structure.Membrane tanks are covered in 4.24.

4.1.6 Integral tanks are tanks that form a structural partof the hull and are influenced in the same manner by the loadsthat stress the adjacent hull structure. Integral tanks arecovered in 4.25.

4.1.7 Semi-membrane tanks are non-self-supportingtanks in the loaded condition and consist of a layer, parts ofwhich are supported through insulation by the adjacent hullstructure. Semi-membrane tanks are covered in 4.26.

4.1.8 In addition to the definitions in 1.2, the definitionsgiven in this Chapter shall apply throughout this Part.

4.2 Application

Unless otherwise specified in part E, the requirements of partsA to D shall apply to all types of tanks, including thosecovered in part F.

Part A Cargo containment

4.3 Functional requirements

LR 4.3.1 Details of the proposed design of cargocontainment systems are to be submitted for consideration,and it is recommended this is done at as early a stage aspossible. For a description of LR’s system of approval, refer tothe Marine Survey Guidance System. See also LR 1.3.




Cargo Containment

4.3.1 The design life of the cargo containment systemshall not be less than the design life of the ship unit.

LR 4.3.2 Cargo containment systems shall be designedwith site-specific environmental loads for the proposed area ofoperation. The cargo containment system shall also bedesigned for all transit conditions as applicable to the opera-tional philosophy of the unit; this includes delivery voyagesand sail-away disconnect conditions.

4.3.3 Cargo containment systems shall be designed withsuitable safety margins:

.1 to withstand, in the intact condition, the environ-mental conditions anticipated for the cargocontainment system’s design life and the loadingconditions appropriate for them, which includeloads derived for the following scenarios: on-siteoperation, inspection/maintenance, transit/disconnect and accidental. The most onerousloading conditions are to be considered.

.2 that are appropriate for uncertainties in loads,structural modelling, fatigue, corrosion, thermaleffects, material variability, ageing and construc-tion tolerances.

4.3.4 The cargo containment system structural strengthshall be assessed against failure modes, including but notlimited to plastic deformation, buckling, and fatigue. Thespecific design conditions that should be considered for thedesign of each cargo containment system are given in 4.21to 4.26. There are three main categories of design conditions:

.1 Ultimate design conditions – The cargocontainment system structure and its structuralcomponents shall withstand loads liable to occurduring its construction, testing and anticipateduse in service, without loss of structural integrity.The design shall take into account proper combi-nations of the following loads:• Internal pressure.• External pressure.• Dynamic loads due to the motion of the ship

unit.• Thermal loads.• Sloshing loads.• Loads corresponding to deflections of the

ship unit.• Tank and cargo weight with the corresponding

reaction in way of supports.• Insulation weight.• Loads in way of towers and other attach-

ments.• Test loads.• 10 000 year return period loading (this require-ment may be waived where it can be proven thatit is not appropriate, on a site-specific basis).

.2 Fatigue design conditions – The cargo contain-ment system structure and its structuralcomponents shall not fail under accumulatedcyclic loading.

.3 Accident design conditions – The cargocontainment system shall provide the indicatedresponse to each of the following accident condi-tions (accidental or abnormal events), addressedin this Part:• Fire – The cargo containment systems shall

sustain without rupture the rise in internalpressure specified in 8.4.1 under the firescenarios envisaged therein.

• Flooded compartment causing buoyancy ontank – The anti-flotation arrangements shallsustain the upward force, specified in 4.15.1and there should be no endangering plasticdeformation to the hull.

4.3.5 Measures shall be applied to ensure that scantlingsrequired meet the structural strength provisions and will bemaintained throughout the design life. Measures include, butare not limited to, material selection, coatings, corrosion additions, cathodic protection and inerting.Corrosion allowance need not be required in addition to thethickness resulting from the structural analysis. However,where there is no environmental control, such as inertingaround the cargo tank, or where the cargo is of a corrosivenature, LR may require a suitable corrosion allowance.

LR 4.3.3 In areas where excessive corrosion might beexpected, a corrosion addition may be required if means ofprotection are not installed.

4.3.6 An inspection/survey plan for the cargo contain-ment system shall be developed and approved at the time ofbuild. The inspection/survey plan shall identify areas that needinspection during surveys throughout the cargo containmentsystem’s life and in particular all necessary in-service surveyand maintenance that was assumed when selecting cargocontainment system design parameters. Cargo containmentsystems shall be designed, constructed and equipped toprovide adequate means of access to areas that need inspec-tion as specified in the inspection/survey plan. Cargocontainment systems, including all associated internal equip-ment shall be designed and built to ensure safety duringoperations, inspection and maintenance (see 3.5).

4.4 Cargo containment safety principles

4.4.1 The containment systems shall be provided with afull secondary liquid-tight barrier capable of safely containingall potential leakages through the primary barrier and, inconjunction with the thermal insulation system, of preventinglowering of the temperature of the structure of the ship unitto an unsafe level.

4.4.2 However, the size and configuration or arrange-ment of the secondary barrier can be reduced where anequivalent level of safety can be demonstrated in accordancewith the requirements of 4.4.3 to 4.4.5 as applicable.



LLOYD’S REGISTER2

Cargo Containment

4.4.3 Cargo containment systems for which the proba-bility for structural failures to develop into a critical state hasbeen determined to be extremely low, but where the possibilityof leakages through the primary barrier cannot be excluded,shall be equipped with a partial secondary barrier and smallleak protection system capable of safely handling and disposing of the leakages.The arrangements shall comply with the following require-ments:

.1 Failure developments that can be reliablydetected before reaching a critical state (e.g. bygas detection or inspection) shall have a sufficiently long development time for remedialactions to be taken.

.2 Failure developments that cannot be safelydetected before reaching a critical state shallhave a predicted development time that is muchlonger than the expected lifetime of the tank.

4.4.4 No secondary barrier is required for cargo contain-ment systems, e.g. Type C independent tanks, where theprobability for structural failures and leakages through theprimary barrier is extremely low and can be neglected.

4.4.5 No secondary barrier is required where the cargotemperature at atmospheric pressure is at or above –10°C.

4.5 Secondary barriers in relation to tank types

Secondary barriers in relation to the tank types defined in 4.21to 4.26 shall be provided in accordance with Table 4.5.1.

4.6 Design of secondary barriers

4.6.1 Where the cargo temperature at atmospheric pressure is not below –55°C, the hull structure may act as asecondary barrier based on the following:

.1 the hull material shall be suitable for the cargotemperature at atmospheric pressure as requiredby 4.19.1.4; and

.2 the design shall be such that this temperature willnot result in unacceptable hull stresses.

4.6.2 The design of the secondary barrier shall be suchthat:

.1 it is capable of containing any envisaged leakageof liquid cargo for a period of 15 days, unlessdifferent project-specific requirements apply,taking into account the load spectrum referred toin 4.18.2.6. Project-specific requirements are tobe submitted for consideration.

.2 physical, mechanical, or operational events withinthe cargo tank that could cause failure of theprimary barrier shall not impair the due functionof the secondary barrier, or vice versa.

.3 failure of a support or an attachment to the hullstructure will not lead to loss of liquid tightnessof both the primary and secondary barriers.

.4 it is capable of being periodically checked for itseffectiveness by means acceptable to LR of avisual inspection or a pressure/vacuum test orother suitable means carried out according to adocumented procedure agreed with LR.

LR 4.6.1 Proposals for the periodical examination of the secondary barrier are to be submitted for consideration.

.5 The methods required in 4.6.2.4 shall beapproved by LR and shall include, where applicableto the test procedure:1. Details on the size of defect acceptable

and the location within the secondary barrier, before its liquid tight effectiveness is compromised.

2. Accuracy and range of values of the proposed method for detecting defects in 4.6.2.5.1.

3. Scaling factors to be used if full scale model testing is not undertaken.

4. Effects of thermal and mechanical cyclic loading on the effectiveness of the proposed test.

.6 The secondary barrier shall fulfil its functionalrequirements at a static angle of heel of 30°.




Table 4.5.1 Secondary barriers in relation to tanktypes

Cargotemperature at –10°C Below –10°C Below –55°Catmospheric and above down to –55°C

pressure

Basic tank type No Hull may act Separatesecondary as secondary secondary

barrier barrier barrier whererequired required

Integral Tank type not normally allowed, see Note 1

Membrane Complete secondary barrier

Semi-membrane Complete secondary barriersee Note 2

IndependentType A Complete secondary barrierType B Partial secondary barrierType C No secondary barrier required

NOTES1. A complete secondary barrier should normally be required if

cargoes with a temperature at atmospheric pressure below–10°C are permitted in accordance with 4.25.1.

2. In the case of semi-membrane tanks that comply in allrespects with the requirements applicable to Type B independent tanks, except for the manner of support, theAdministration may, after special consideration, accept apartial secondary barrier.

Cargo Containment

4.7 Partial secondary barriers and primary barriersmall leak protection system

4.7.1 Partial secondary barriers shall be used with a smallleak protection system and meet all the requirements in 4.6.2.The small leak protection system shall include means todetect a leak in the primary barrier, provision such as a sprayshield to deflect any liquid cargo down into the partialsecondary barrier, and means to dispose of the liquid, whichmay be by natural evaporation.

4.7.2 The capacity of the partial secondary barrier shallbe determined, based on the cargo leakage correspondingto the extent of failure resulting from the load spectrumreferred to in 4.18.2.6, after the initial detection of a primaryleak. Due account may be taken of liquid evaporation, rate ofleakage, pumping capacity and other relevant factors.

4.7.3 The required liquid leakage detection may be bymeans of liquid sensors, or by an effective use of pressure,temperature or gas detection systems, or any combinationthereof.

4.8 Supporting arrangements

4.8.1 The cargo tanks shall be supported by the hull in amanner that prevents bodily movement of the tank under thestatic and dynamic loads defined in 4.12 to 4.15, where applicable, while allowing contraction and expansion of thetank under temperature variations and hull deflections without undue stressing of the tank and the hull.

LR 4.8.1 Tank supporting arrangements are generally tobe located in way of the primary support structure of the tankand the hull of the ship unit. Steel seatings are to be arranged,where possible, on both the inner bottom and underside ofthe cargo tank so as to ensure an effective distribution of thetransmitted load and reactions into the cargo tanks anddouble bottom structure.

LR 4.8.2 The strength of supporting arrangements is tobe verified by direct calculation.

4.8.2 Anti-flotation arrangements shall be provided forindependent tanks and be capable of withstanding the loadsdefined in 4.15.1 without plastic deformation likely to endangerthe hull structure.

4.8.3 Supports and supporting arrangements shall with-stand the loads defined in 4.13.8 and 4.15, but these loadsneed not be combined with each other or with wave-inducedloads.

LR 4.8.3 An adequate clearance is to be providedbetween the anti-flotation chocks and the hull of the ship unitin all operational conditions.

LR 4.8.4 The effects on the supporting arrangementsof the 10 000 year return period wave loading are to beconsidered as follows:• Resulting acceleration loadings.• Hull interaction loadings.Calculations and analyses are to be performed to show thatthere would be no gross failure of the supporting arrange-ments in this event as prescribed above for each tank type.

4.9 Associated structure and equipment

4.9.1 Cargo containment systems are to be designed forthe loads imposed by associated structure and equipment.This includes pump towers, cargo domes, cargo pumps andpiping, stripping pumps and piping, inert gas piping, accesshatches, ladders, piping penetrations, liquid level gauges,independent level alarm gauges, spray nozzles, and instru-mentation systems (such as pressure, temperature and straingauges).

4.10 Thermal insulation

4.10.1 Thermal insulation shall be provided as required toprotect the hull from temperatures below those allowable (see4.19.1) and to limit the heat flux into the tank to the levels thatcan be maintained by the pressure and temperature controlsystem applied in Chapter 7.

4.10.2 In determining the insulation performance, dueregard should be paid to the amount of the acceptable boil-offin association with the liquefaction or reliquefaction plant onboard, gas consumers if present or other temperature controlsystem.

Part B Design loads

4.11 General

This Section defines the design loads to be considered withregard to the requirements in 4.16, 4.17 and 4.18. Thisincludes:• Load categories (permanent, functional, environmental

and accidental) and the description of the loads.The extent to which these loads should be considereddepends on the type of tank, and is more fully detailed in thefollowing paragraphs.Tanks, together with their supporting structure and otherfixtures, that shall be designed taking into account relevantcombinations of the loads described below.

4.12 Permanent loads

4.12.1 Gravity loadsThe weight of tank, thermal insulation, loads caused bytowers and other attachments.

4.12.2 Permanent external loadsGravity loads of structures and equipment acting externallyon the tank.



LLOYD’S REGISTER4

Cargo Containment

4.13 Functional loads

Loads arising from the operational use of the tank systemshall be classified as functional loads.All functional loads that are essential for ensuring the integrityof the tank system, during all design conditions, shall beconsidered.As a minimum, the effects from the following criteria, as applicable, shall be considered when establishing functionalloads:• Internal pressure.• External pressure.• Thermally induced loads.• Vibration.• Interaction loads.• Loads associated with construction and installation.• Test loads.• Static heel loads.• Weight of cargo.

4.13.1 Internal pressure.1 In all cases, including 4.13.1.2, Po shall not be

less than MARVS..2 For cargo tanks where there is no temperature

control and where the pressure of the cargo isdictated only by the ambient temperature, Poshall not be less than the gauge vapour pressureof the cargo at a temperature equal to the maximum daily mean ambient air temperature forthe unit’s proposed area of operation based onthe 100 year average return period. The ambienttemperature is to be rounded up to the nearestdegree Celsius, and not to be taken as less than45°C unless agreed by LR.

.3 Subject to special consideration by theAdministration and to the limitations given in 4.21to 4.26, for the various tank types, a vapour pressure Ph higher than Po may be accepted forsite-specific conditions where dynamic loads arereduced.

.4 The internal pressure Peq results from the vapourpressure Po or Ph plus the maximum associateddynamic liquid pressure Pgd, but not including theeffects of liquid sloshing loads. Guidance formulaefor associated dynamic liquid pressure Pgd aregiven in 4.27.1.

4.13.2 External pressureExternal design pressure loads shall be based on the difference between the minimum internal pressure and themaximum external pressure to which any portion of the tankmay be simultaneously subjected.

4.13.3 Thermally induced loadsTransient thermally induced loads during cooling down periods shall be considered for tanks intended for cargotemperatures below –55°C.Stationary thermally induced loads shall be considered forcargo containment systems where the design supportingarrangements or attachments and operating temperature maygive rise to significant thermal stresses. See 7.2.

4.13.4 VibrationThe potentially damaging effects of vibration on the cargocontainment system shall be considered.

4.13.5 Interaction loadsThe static component of loads resulting from interactionbetween cargo containment system and the hull structure, aswell as loads from associated structure and equipment, shallbe considered.

4.13.6 Loads associated with construction and installationLoads or conditions associated with construction and installation shall be considered, e.g. lifting.

4.13.7 Test loadsAccount shall be taken of the loads corresponding to the testingof the cargo containment system referred to in 4.21 to 4.26.

4.13.8 Static heel loadsLoads corresponding to the most unfavourable static heelangle within the range 0° to 30° shall be considered.

LR 4.13.1 10 000 year return period loadingThe effects on the containment system of the 10 000 yearreturn period wave loading are to be considered.

4.13.9 Other loadsAny other loads not specifically addressed, which could havean effect on the cargo containment system, shall be taken intoaccount.

4.14 Environmental loads

Environmental loads are defined as those loads on the cargocontainment system that are caused by the surrounding environment and that are not otherwise classified as a permanent, functional or accidental load.

4.14.1 Loads due to ship motionThe determination of dynamic loads shall take into accountthe long-term distribution of ship motion in irregular seas,which the ship unit will experience during its operating life.Account may be taken of the reduction in dynamic loads dueto heading control.The motions of the ship unit shall include surge, sway, heave,roll, pitch and yaw. The accelerations, derived from site-specific wave data and the heading analysis, acting on tanks,shall be estimated at their centre of gravity and include thefollowing components:• vertical acceleration: motion accelerations of heave,

pitch and possibly roll (normal to the base of the shipunit);

• transverse acceleration: motion accelerations of sway,yaw and roll and gravity component of roll;

• longitudinal acceleration: motion accelerations of surgeand pitch and gravity component of pitch.

Methods to predict accelerations due to ship motion shall beproposed and approved by LR.Guidance formulae for acceleration components are given in4.27.2.




Cargo Containment

LR 4.14.1 The determination of the dynamic loads maybe based on the results of model tests and/or by suitable direct calculation methods of the actual loads on thecargo containment system at the site-specific location, takinginto account the following service-related factors:(a) site-specific environmental loads including relevant non-

linear effects;(b) mooring system and riser loads;(c) unit orientation and wave loading directions;(d) long-term service effects at a fixed location;(e) range of tank loading conditions, including empty tanks

required for on-station surveys;(f) potential relocations if applicable.The actual form and weight distribution of the unit and thelongitudinal and transverse locations of the tanks are to betaken into account.

4.14.2 Dynamic interaction loadsAccount shall be taken of the dynamic component of loadsresulting from interaction between cargo containmentsystems and the hull structure, including loads from associatedstructures and equipment.

4.14.3 Sloshing loadsThe sloshing loads on a cargo containment system and internal components, induced by any of the site-specificmotions referred to in 4.14.1, shall be evaluated based onallowable filling levels.When significant sloshing-induced loads are expected to bepresent, special tests and calculations shall be requiredcovering the full range of intended filling levels.

LR 4.14.2 Where loading conditions are proposed,including one or more partially filled tanks, calculations ormodel tests will be required to show that the resulting loadsand pressure are within acceptable limits for the scantlings ofthe tanks. Additionally, investigations should be made toensure that the internal structure, equipment and pipeworkexposed to fluid motion are of adequate strength.

LR 4.14.3 If the liquefied gas storage tanks are to haveno filling restrictions, the capacity of the cargo containmentsystem to resist the greatest predicted sloshing pressures is tobe assessed for fill heights representative of all filling levels inaccordance with this Section.If filling restrictions are contemplated, the capacity of thecargo containment system to resist sloshing predicted pressures needs to be assessed only for fill heights represen-tative of the permitted filling ranges. In this case, the fillingrestrictions are to be stated in the approved Loading Manual.

4.14.4 Snow and ice loadsSnow and icing shall be considered, if relevant.

4.14.5 Loads due to operation in ice conditionsLoads due to operation in ice conditions shall be consideredfor units intended for such service. The effects on the contain-ment system due to additional topside weight as a result ofice accretion, and ice collisions against the hull should beconsidered, see also Pt 3, Ch 6.

4.15 Accidental loads

Accidental loads are defined as loads that are imposed on acargo containment system and its supporting arrangementsunder abnormal and unplanned conditions.

4.15.1 Loads due to floodingFor independent tanks, loads caused by the buoyancy of anempty tank in a hold space, flooded to the summer loaddraught, shall be considered in the design of the anti-flotationchocks and the supporting hull structure.

Part C Structural integrity

4.16 General

The structural design shall ensure that tanks have anadequate capacity to sustain all relevant loads with anadequate margin of safety. This should take into account thepossibility of plastic deformation, buckling, fatigue and loss ofliquid and gas tightness.The structural integrity of cargo containment systems can bedemonstrated by compliance with 4.21 to 4.26, as appropriatefor the cargo containment system type.

4.17 Structural analyses

4.17.1 AnalysisThe design analyses shall be based on accepted principles ofstatics, dynamics and strength of materials.Simplified methods or simplified analyses may be used tocalculate the load effects, provided that they are conserva-tive. Model tests may be used in combination with, or insteadof, theoretical calculations. In cases where theoretical methods are inadequate, model or full-scale tests may berequired.When determining responses to dynamic loads, the dynamiceffect shall be taken into account where it may affect structural integrity.

LR 4.17.1 Where direct calculation procedures areadopted, the assumptions made and other details of thecalculations are to be submitted.

4.17.2 Load scenariosFor each location or part of the cargo containment system tobe considered and for each possible mode of failure to beanalysed, all relevant combinations of loads that may actsimultaneously shall be considered.The most onerous load scenarios for all relevant phases of thelife-cycle shall be considered. Loads during construction/handling, installation, on-site operation, inspection/maintenance including testing and in transit/disconnectconditions shall be considered, as applicable.



LLOYD’S REGISTER6

4.18.1.3 For the purpose of ultimate strength assessmentthe following material parameters apply:

.1 Re = specified minimum yield stress at room temperature (N/mm2). If the stress-strain curve does not show a defined yield stress, the 0,2 per cent proof stress applies.

Rm = specified minimum tensile strength at room temperature (N/mm2).

NOTE

For welded connections where under-matchedwelds, i.e. where the weld metal has lower tensilestrength than the parent metal, are unavoidable,such as in some aluminium alloys, the respectiveRe and Rm of the welds, after any applied heattreatment, shall be used. In such cases the trans-verse weld tensile strength shall not be less thanthe actual yield strength of the parent metal. Ifthis cannot be achieved, welded structures madefrom such materials shall not be incorporated incargo containment systems.

.2 The above properties shall correspond to theminimum specified mechanical properties of thematerial, including the weld metal in the as-fabri-cated condition. Subject to special considerationby LR, account may be taken of the enhancedyield stress and tensile strength at low tempera-ture.

4.18.1.4 The equivalent stress σc (von Mises, Huber) shallbe determined by:

σc =

whereσx = total normal stress in x-directionσy = total normal stress in y-directionσz = total normal stress in z-directionτxy = total shear stress in x-y plane.τxz = total shear stress in x-z planeτyz = total shear stress in y-z plane.

4.18.1.5 Allowable stresses for materials other than thosecovered by Chapter 6 shall be subject to approval by LR ineach case.

LR 4.18.1 Details of the proposals are to be submittedfor consideration.

4.18.1.6 Stresses may be further limited by fatigue analysis,crack propagation analysis and buckling criteria.

LR 4.18.2 The stresses resulting from the 10 000 yearreturn period wave loading are not to exceed yield, or a higherstress level, provided permanent deformation can be permitted.

4.18.2 Fatigue design condition

4.18.2.1 The fatigue design condition is the design conditionwith respect to accumulated cyclic loading.

σx2 + σy

2 + σz2 – σxσy – σxσz – σyσz + 3 (τxy

2 + τxz2 + τyz

2)

Cargo Containment

4.17.3 When the static and dynamic stresses are calculated separately and unless other methods of calcula-tion are justified, the total stresses shall be calculatedaccording to:

σx = σx.st ±

σy = σy.st ±

σz = σz.st ±

τxy = τxy.st ±

τxz = τxz.st ±

τyz = τyz.st ±

where:σx.st, σy.st, σz.st, τxy.st, τxz.st and τyz.st = static stresses

σx.dyn, σy.dyn, σz.dyn, τxy.dyn, τxz.dyn and τyz.dyn = dynamic stresses

Each shall be determined separately from accelerationcomponents and hull strain components due to deflectionand torsion.

4.18 Design conditions

All relevant failure modes shall be considered in the design forall relevant load scenarios and design conditions. The designconditions are given in the earlier part of this Chapter, and theload scenarios are covered by 4.17.2.

4.18.1 Ultimate design conditionStructural capacity may be determined by testing, or by analysis, taking into account both the elastic and plasticmaterial properties, or by simplified linear elastic analysis.

4.18.1.1 Plastic deformation and buckling shall be considered.

4.18.1.2 Analysis shall be based on characteristic loadvalues as follows:

Permanent Loads Expected ValuesFunctional Loads Specified ValuesEnvironmental Loads For wave loads; most probable

largest load encountered by the ship unit during its operating life.

Σ(τyz.dyn)2

Σ(τxz.dyn)2

Σ(τxy.dyn)2

Σ(σz.dyn)2

Σ(σy.dyn)2

Σ(σx.dyn)2




Cargo Containment

4.18.2.2 Where a fatigue analysis is required, the maximumallowable cumulative fatigue damage ratio is to be less than orequal to 0,5, but is to be no greater than 0,33 for any parts ofthe supporting structure which are not accessible for inspec-tion during the service life of the unit.The fatigue assessment of the cargo containment system is tobe verified in accordance with the LR ShipRight-FOI Design,Construction and Operation Procedure for Floating OffshoreInstallations.The loading/unloading history is to be consistent with theintended operation of the ship unit. Plastic strain is to beaccounted for in the low cycle region. Loading and unloadingcycles are to include a complete pressure and thermal cycle.The fatigue damage shall be based on the design life of thetank but not less than 108 wave encounters.

4.18.2.3 Where required, the cargo containment systemshall be subject to fatigue analysis, considering all fatigueloads and their appropriate combinations for the expected lifeof the cargo containment system. Consideration shall begiven to various filling conditions.

4.18.2.4 Design S-N curves used in the analysis shall beapplicable to the materials and weldments, constructiondetails, fabrication procedures and applicable state of thestress envisioned.The S-N curves shall be based on a 97,6 per cent probabilityof survival corresponding to the mean minus two standarddeviation curves of relevant experimental data up to final failure. Use of S-N curves derived in a different way requiresadjustments to the acceptable Cw values specified in 4.18.2.7to 4.18.2.9.

4.18.2.5 Analysis shall be based on characteristic loadvalues as follows:

Permanent loads Expected valuesFunctional loads Specified values or specified

historyEnvironmental loads Expected load history, but not

less than 108 cyclesIf simplified dynamic loading spectra are used for the estimationof the fatigue life, those shall be specially considered by LR.

4.18.2.6 Where the size of the secondary barrier is reduced,as is provided for in 4.4.3, fracture mechanics analyses offatigue crack growth shall be carried out for the primarybarrier to determine:• Crack propagation paths in the structure.• Crack growth rate.• The time required for a crack to propagate to cause a

leakage from the tank.• The size and shape of through-thickness cracks.• The time required for detectable cracks to reach a

critical state.The fracture mechanics are in general based on crack growthdata taken as a mean value plus two standard deviations ofthe test data.In analysing crack propagation the largest initial crack orequivalent defect not detectable by the inspection methodapplied shall be assumed, taking into account the allowablenon-destructive testing and visual inspection criterion asapplicable.For the crack propagation analysis under the condition specified in 4.18.2.7, the simplified load distribution and

sequence over a period of 15 days may be used, unlessdifferent project-specific requirements apply. Project-specificrequirements are to be submitted for consideration. Suchdistributions may be obtained as indicated in Fig. 4.1. Loaddistribution and sequence for longer periods, such as in4.18.2.8 and 4.18.2.9 shall be approved by LR.The arrangements shall comply with 4.18.2.7 to 4.18.2.9 asapplicable:

4.18.2.7 For failures that can be reliably detected by meansof leakage detection;• Cw shall be less than or equal to 0,5.• The predicted remaining failure development time, from

the point of detection of leakage until reaching a criticalstate, shall not be less than 15 days unless differentproject-specific requirements apply. Project-specificrequirements are to be submitted for consideration.

4.18.2.8 For failures that cannot be detected by leakage but that can be reliably detected at the time of in-service inspections;• Cw shall be less than or equal to 0,5.• Predicted remaining failure development time, from the

largest crack not detectable by in-service inspectionmethods until reaching a critical state, shall not be lessthan three times the inspection interval.

4.18.2.9 In particular locations of the tank where effectivedefect or crack development detection cannot be assured,the following, more stringent, fatigue acceptance criteriashould be applied as a minimum;• Cw shall be less than or equal to 0,1.• The predicted failure development time, from the

assumed initial defect until reaching a critical state, shallnot be less than three times the lifetime of the tank.



LLOYD’S REGISTER8

σo

1 10 102 103 104 105 2×105

Response cycles

~ 15 days

σo = most probable maximum stress over the life cycle of the ship unitResponse cycle scale is logarithmic; the value of 2×105 is given as an example of estimate

Fig. 4.1 Simplified load distribution

Cargo Containment

4.18.3 Accident design conditionThe accident design condition is a design condition for accidental loads with extremely low probability of occurrence.Analysis shall be based on the characteristic values asfollows:

Permanent loads Expected valuesFunctional loads Specified valuesEnvironmental loads Specified valuesAccidental loads Specified values or expected

valuesLoads mentioned in 4.13.8 and 4.15 need not be combinedwith each other or with wave induced loads.

Part D Materials and construction

4.19 Materials

LR 4.19.1 The specification and plans of the cargo contain-ment system including the insulation are to be submitted forapproval. The materials used are to be approved by LR, seeChapter 6. For the plans to be submitted, see LR 1.6.

4.19.1 Materials forming the structure of the ship unit

4.19.1.1 To determine the grade of plate and sections usedin the hull structure, a temperature calculation shall beperformed for all tank types when the cargo temperature isbelow –10°C. The following assumptions should be made inthis calculation:

.1 The primary barrier of all tanks shall be assumedto be at the cargo temperature.

.2 In addition to item 1, where a complete or partialsecondary barrier is required it shall be assumedto be at the cargo temperature at atmosphericpressure for any one tank only.

.3 The ambient temperatures for air and sea-waterare to be taken at their lowest daily mean temper-atures for the unit’s proposed area of operationbased on the 100 year average return period.The ambient temperatures are to be roundeddown to the nearest degree Celsius. The ambient temperatures are not to be taken asgreater than 5°C for air and 0°C for sea-waterunless agreed by LR.

.4 Still air and sea water conditions shall be assumed,i.e. no adjustment for forced convection.

.5 Degradation of the thermal insulation propertiesover the life of the ship unit due to factors such asthermal and mechanical ageing, compaction,ship motions and tank vibrations as defined in4.19.3.6 and 4.19.3.7 shall be assumed.

.6 The cooling effect of the rising boil-off vapourfrom the leaked cargo should be taken intoaccount where applicable.

.7 No credit shall be given for any means of heating,except as described in 4.19.1.5.

.8 For members connecting inner and outer hulls,the mean temperature may be taken for deter-mining the steel grade.

LR 4.19.2 When heat transmission studies are carriedout, the heat balance method is acceptable to LR.

4.19.1.2 The shell and deck plating of the ship unit and allstiffeners attached thereto shall be in accordance with therequirements of Part 10 and this Part. If the calculatedtemperature of the material in the design condition is below–5°C due to the influence of the cargo temperature and ambient sea and air temperatures, the material shall be inaccordance with Table 6.5. The ambient sea and air temper-atures are to be determined as defined in 4.19.1.1.3.

4.19.1.3 The materials of all other hull structures for whichthe calculated temperature in the design condition is below0°C, due to the influence of cargo temperature and ambientsea and air temperatures, and that do not form the secondarybarrier, shall also be in accordance with Table 6.5. Thisincludes hull structure supporting the cargo tanks, innerbottom plating, longitudinal bulkhead plating, transverse bulk-head plating, floors, webs, stringers and all attached stiffeningmembers. The ambient sea and air temperatures are to bedetermined as defined in 4.19.1.1.3.

4.19.1.4 The hull material forming the secondary barrier shallbe in accordance with Table 6.2. Where the secondary barrieris formed by the deck or side shell plating, the material graderequired by Table 6.2 shall be carried into the adjacent deck orside shell plating, where applicable, to a suitable extent.

4.19.1.5 Means of heating structural materials may be usedto ensure that the material temperature does not fall belowthe minimum allowed for the grade of material specified inTable 6.5. In the calculations required in 4.19.1.1, credit forsuch heating may be taken in accordance with the following:

.1 for any transverse hull structure;

.2 for longitudinal hull structure referred to in4.19.1.2 and 4.19.1.3 where colder ambienttemperatures are specified, provided the materialremains suitable for the ambient temperatureconditions of +5°C for air and 0°C for sea-waterwith no credit taken in the calculations for heating;and

.3 as an alternative to 4.19.1.5.2, for longitudinalbulkhead between cargo tanks, credit may betaken for heating provided the material remainssuitable for a minimum design temperature of –30°C, or a temperature 30°C lower than that determined by 4.19.1.1 with the heating considered, whichever is less. In this case, thelongitudinal strength of the ship unit shall complywith SOLAS Regulation II-1/3-1 for both whenthose bulkhead(s) are considered effective andnot.




Cargo Containment

4.19.1.6 The means of heating referred to in 4.19.1.5 shallcomply with the following requirements:

.1 the heating system shall be arranged so that, inthe event of failure in any part of the system,standby heating can be maintained equal to notless than 100 per cent of the theoretical heatrequirement;

.2 the heating system shall be considered as anessential auxiliary. All electrical components of atleast one of the systems provided in accordancewith 4.19.1.5.1 shall be supplied from the emer-gency source of electrical power; and

.3 the design and construction of the heatingsystem shall be included in the approval of thecontainment system by LR.

LR 4.19.3 Details of the proposed heating system are tobe submitted.

4.19.2 Materials of primary and secondary barriers

4.19.2.1 Metallic materials used in the construction ofprimary and secondary barriers not forming the hull, shall besuitable for the design loads that they may be subjected to,and be in accordance with Table 6.1, 6.2 or 6.3.

4.19.2.2 Materials, either non-metallic or metallic but notcovered by Tables 6.1, 6.2 and 6.3, used in the primary andsecondary barriers may be approved by LR considering thedesign loads that they may be subjected to, their propertiesand their intended use.

4.19.2.3 Where non-metallic materials, including composites,are used for or incorporated in the primary or secondary barriers, they shall be tested for the following properties, asapplicable, to ensure that they are adequate for the intendedservice:• compatibility with the cargoes;• solubility in cargo;• absorption of cargo;• ageing;• density;• mechanical properties;• thermal expansion and contraction;• abrasion;• cohesion;• resistance to vibrations;• resistance to fire and flame spread;• resistance to fatigue failure and crack propagation;• influence of water;• resistance to cargo pressure.

4.19.2.4 The above properties, where applicable, shall betested for the range between the expected maximum temper-ature in service and 5°C below the minimum designtemperature, but not lower than –196°C.

4.19.2.5 Where non-metallic materials, including composites,are used for the primary and secondary barriers, the joiningprocesses shall also be tested as described above.

4.19.2.5.1 Guidance on the use of non-metallic materials inthe construction of primary and secondary barriers is providedin Appendix 1.

4.19.2.6 Consideration may be given to the use of materialsin the primary and secondary barrier, which are not resistantto fire and flame spread, provided they are protected by asuitable system such as a permanent inert gas environment,or are provided with a fire retardant barrier.

4.19.3 Thermal insulation and other materials used in cargo containment systems

4.19.3.1 Load-bearing thermal insulation and other materialsused in cargo containment systems shall be suitable for thedesign loads.

4.19.3.2 Thermal insulation and other materials used incargo containment systems shall have the following properties,as applicable, to ensure that they are adequate for theintended service:• compatibility with the cargoes;• solubility in the cargo;• absorption of the cargo;• shrinkage;• ageing;• closed cell content;• density;• mechanical properties, to the extent that they are

subjected to cargo and other loading effects, thermalexpansion and contraction;

• abrasion;• cohesion;• thermal conductivity;• resistance to vibrations;• resistance to fire and flame spread;• resistance to fatigue failure and crack propagation.

LR 4.19.4 In addition to the requirements given in4.19.3.2, fatigue and crack propagation properties for insulation in membrane systems are also to be submitted.Insulation materials are to be approved by LR. Where applicable, these requirements also apply to any adhesive,sealers, vapour barriers, coatings or similar products used inthe insulation system, any material used to give strength tothe insulation system, components used to hold the insulation in place and any non-metallic membrane materials.Such products are to be compatible with the insulation.

4.19.3.3 The above properties, where applicable, shall betested for the range between the expected maximum temper-ature in service and 5°C below the minimum designtemperature, but not lower than –196°C.

4.19.3.4 Due to location or environmental conditions, thermal insulation materials shall have suitable properties ofresistance to fire and flame spread and shall be adequatelyprotected against penetration of water vapour and mechanicaldamage. Where the thermal insulation is located on or abovethe exposed deck, and in way of tank cover penetrations, itshall have suitable fire resistance properties in accordancewith a recognised Standard acceptable to LR or be coveredwith a material having low flame spread characteristics and forming an efficient approved vapour seal.




Cargo Containment

LR 4.19.5 Where the insulation is located on or immediately adjacent to the open deck, or is in an interbarrieror hold space not kept inerted in accordance with 9.2.1, it isto have suitable fire resistance properties. If the insulation islocated in an inerted atmosphere and is separated from theopen deck by a void space or ballast tank, then insulationhaving fire resisting properties is not required.In addition, all insulation is to be covered with a coveringhaving low flame spread characteristics.An efficient vapour barrier (seal) is to be provided on the outersurface of the insulation. The vapour barrier is to be of anapproved type.

4.19.3.5 Thermal insulation that does not meet recognisedStandards acceptable to LR for fire resistance may be used inhold spaces that are not kept permanently inerted, providedits surfaces are covered with material with low flame spreadcharacteristics and that forms an efficient approved vapourseal.

4.19.3.6 Testing for thermal conductivity of thermal insulationshall be carried out on suitably aged samples.

4.19.3.7 Where powder or granulated thermal insulation isused, measures shall be taken to reduce compaction inservice, for example due to vibrations, and to maintain therequired thermal conductivity and also prevent any undueincrease of pressure on the cargo containment system.

LR 4.19.6 Particular attention is to be paid to the cleaningof the steelwork prior to the application of the insulation.Where insulation is to be foamed or sprayed in situ, the minimum steelwork temperature at the time of application isto be indicated in the specification in addition to environmentalconditions.

4.20 Construction processes

LR 4.20.1 A construction, testing and inspection (CTI)plan for the installation of the containment system is to besubmitted for approval. This plan is to list the followingsequentially for each stage of installation, testing and inspection:(a) The method to be used.(b) The acceptance criteria.(c) The form of record to be made.(d) The involvement of the shipyard, containment system

designer where relevant, and LR Surveyor.The testing and inspection should be commensurate withassumptions made in the design of the containment system,see 4.18.2.6. Further detailed documents, which may becross-referenced by the CTI plan, are to be submitted forapproval as applicable.

LR 4.20.2 A detailed quality assurance/quality control(QA/QC) programme shall be applied to ensure the continuedconformity of materials in the containment system duringinstallation and service. The quality assurance/quality controlprogramme shall include the procedure for fabrication,storage, handling and preventive actions to guard againstexposure of a material to harmful effects. The proposedprocedure is to be submitted to LR for consideration. Allmaterials in the containment system are also to be consideredand included in the procedure. See also Appendix 1,5.

4.20.1 Weld joint design

4.20.1.1 All welded joints of the shells of independent tanksshall be of the in-plane butt weld full penetration type. Fordome-to-shell connections only, tee welds of the full penetra-tion type may be used depending on the results of the testscarried out at the approval of the welding procedure. Exceptfor small penetrations on domes, nozzle welds are also to bedesigned with full penetration.

LR 4.20.3 Except for the dome-to-shell connections, T-butt welds will not be accepted in the shell.

4.20.1.2 Welding joint details for Type C independent tanks,and for the liquid-tight primary barriers of Type B independenttanks primarily constructed of curved surfaces, shall be asfollows:

.1 All longitudinal and circumferential joints shall beof butt welded, full penetration, double vee orsingle vee type. Full penetration butt welds shallbe obtained by double welding or by the use ofbacking rings. If used, backing rings shall beremoved except from very small process pressure vessels. Other edge preparations maybe permitted, depending on the results of thetests carried out at the approval of the weldingprocedure.

.2 The bevel preparation of the joints between thetank body and domes and between domes andrelevant fittings shall be designed according to astandard acceptable to LR. All welds connectingnozzles, domes or other penetrations of thevessel and all welds connecting flanges to thevessel or nozzles shall be full penetration welds.

LR 4.20.4 See also Pt 5, Ch 10,14 of the Rules forShips.

4.20.1.3 Where applicable, all the construction processesand testing, except that specified in 4.20.3 shall be done inaccordance with the applicable provisions of Chapter 6.

4.20.2 Design for gluing and other joining processesThe design of the joint to be glued (or joined by some otherprocess except welding) shall take account of the strengthcharacteristics of the joining process.

4.20.3 Testing during construction

4.20.3.1 All cargo tanks and process pressure vessels shallbe subjected to hydrostatic or hydro-pneumatic pressuretesting in accordance with 4.21 to 4.26, as applicable for thetank type.

4.20.3.2 All tanks shall be subject to a tightness test whichmay be performed in combination with the pressure testreferred to in 4.20.3.1.

4.20.3.3 Requirements with respect to inspection ofsecondary barriers shall be decided by LR in each case,taking into account the accessibility of the barrier. See also4.6.2.




Cargo Containment

4.20.3.4 The Administration may require that, for ship unitsfitted with novel Type B independent tanks, at least one prototype tank and its supporting structures shall be instrumented with strain gauges or other suitable equipmentto confirm stress levels. Similar instrumentation may berequired for Type C independent tanks, depending on theirconfiguration and on the arrangement of their supports andattachments.

4.20.3.5 The overall performance of the cargo containmentsystem shall be verified for compliance with the designparameters during entry into service in accordance with thesurvey procedure. Records of the performance of the components and equipment, essential to verify the designparameters, shall be maintained and be available to theAdministration.

LR 4.20.5 The overall performance of the cargo contain-ment system is to be verified for compliance with the designparameters during initial acceptance cargo trials. The initialtrials are to be witnessed by LR’s Surveyors, and are todemonstrate that the system is capable of being inerted,cooled, loaded and discharged in a satisfactory manner, andthat all safety devices function correctly.The temperature at which these tests are carried out is to beat or near the minimum cargo temperature. Where a refriger-ation plant is fitted, its operation is to be demonstrated to theSurveyors. Records of the plant performance taken duringentry into service at minimum temperature are to be submitted.Logs of plant performance are to be maintained for examination by the Surveyors when requested.

4.20.3.6 Heating arrangements, if fitted in accordance with4.19.1.5 and 4.19.1.6, shall be tested for required heat outputand heat distribution.

4.20.3.7 The cargo containment system shall be inspectedfor cold spots during or immediately following entry intoservice. Inspection of the integrity of thermal insulationsurfaces that can not be visually checked shall be carried outin accordance with recognised Standards.

Part E Tank types

4.21 Type A independent tanks

4.21.1 Design basis

4.21.1.1 Type A independent tanks are tanks primarilydesigned using classical ship-structural analysis procedures.Type A independent tanks are to be designed in accordancewith LR 4.21.1 and LR 4.21.2. Where such tanks are primarilyconstructed of plane surfaces, the design vapour pressure Poshall be less than 0,07 MPa.

4.21.1.2 If the cargo temperature at atmospheric pressureis below –10°C, a complete secondary barrier is required asdefined in 4.5. The secondary barrier shall be designed inaccordance with 4.6.

4.21.2 Structural analysis

4.21.2.1 A structural analysis shall be performed taking intoaccount the internal pressure as indicated in 4.13.1, and theinteraction loads with the supporting and keying system aswell as a reasonable part of the hull of the ship unit.

4.21.2.2 For parts such as supporting structures not other-wise covered by the requirements of this Part, stresses shallbe determined by direct calculations, taking into account theloads referred to in 4.12 to 4.15 as far as applicable, and thedeflection of the ship unit in way of supporting structures.

4.20.2.3 The tanks with supports shall be designed for theaccidental loads specified in 4.15. These loads need not becombined with each other or with environmental loads.

LR 4.21.1 Symbols:b = width of plating supported, in metres

f = 1,1 – but need not exceed 1,0

fs = 2,7 for nickel steels and carbon manganese steels3,9 for austenitic steels and aluminium alloys

h = vertical distance, from the middle of the effectivespan of stiffener or transverse to the top of thetank, in metres

l = effective span or girder or web, in metres, see Pt 3,Ch 3,3.3 of the Rules for Ships

le = effective length of stiffening member, in metres, seePt 3, Ch 3,3.3 of the Rules for Ships

lt, ls, lb, lc are effective spans measured according to Fig. LR 4.1

ρ = maximum density of the cargo, in kg/m3, at thedesign temperature

k = higher tensile steel factor, see Pt 3, Ch 2,1.2 of theRules for Ships

tp = thickness, in mm, of the attached load bearing plating. Where this varies over the effective widthof plating, the mean thickness is to be used

Peq = the internal pressure head, in bar, as derived from4.13.1.4 and measured at a point on the plate onethird of the depth of the plate above its lower edge

s = spacing of bulkhead stiffeners, in mmS = spacing of primary members, in metres

Sw and s1 are as defined in Fig. 10.5.1 in Pt 3, Ch 10,5.2 ofthe Rules for Ships.The remaining symbols are as defined in Pt 4, Ch 1,9,2 of theRules for Ships. The lateral and torsional stability of stiffeners should comply with the requirements of Pt 4, Ch 9,5.6 of the Rules for Ships.

s2500S




Cargo ContainmentRULES AND REGULATIONS FOR THE CLASSIFICATION OF A FLOATING OFFSHORE INSTALLATION AT A FIXED LOCATION, June 2013



lt top transverse

l s s

ide

tran

sver

se

l c c

entr

e tr

ansv

erse

lb bottom transverse

B

B

A

A

A

A

A

A

B

r5

r5

r5

r5

r5

r

r

r

r

r

r5

r5

r5

NOTE

r should generally be not less than twice the depth of the smaller adjacent web

Fig. LR 4.1 Measurement of spans

Cargo Containment

LR 4.21.2 The scantlings of Type A independent tanksare to comply with the following:(a) Minimum thickness.

No part of the cargo tank structure is to be less than 7,5 mm in thickness.

(b) Boundary plating.The thickness of plating forming the boundaries of cargotanks is to be not less than 7,5 mm, nor less than:

t = 0,011s f mm

NOTE

An additional corrosion allowance of 1 mm is to beadded to the thickness derived if the cargo is of corrosive nature, see also 4.3.5 and LR 4.3.3.

(c) Rolled or built stiffeners.The section modulus of rolled or built stiffeners on plating forming tank boundaries is to be not less than:

Z = cm3.

(d) Transverses.The scantlings of transverse members are normally to bederived using direct calculation methods. The structuralanalysis is to take account of the internal pressuredefined in 4.13.1.4 and also those resulting from structural test loading conditions. Proper account is alsoto be taken of structural model end constraints, shearand axial forces present and any interaction from thedouble bottom structure through the cargo tanksupports.As an initial estimate, the scantlings of the primary trans-verses may be taken as:top transverse

Z = 72Peq s lt2 k cm3

topside transverse

Z = 52Peq s lt2 k cm3

side transverse

Z = 56Peq s ls2 k cm3

bottom transverse

Z = 56Peq s lb2 k cm3

centreline bulkhead transverse

Z = 40Peq s lc2 k cm3

The depth of the bottom transverse web is generally tobe not less than lb/4.Web stiffening is to be in accordance with Pt 4, Ch 9,10.5 of the Rules for Ships with the application ofthe stiffening requirements as shown in Fig. LR 4.1.

(e) Tank end webs and girders.The section modulus of vertical webs and horizontalgirders is to be not less than:

Z = 85Peq b l2 k cm3.

(f) Internal bulkheads (perforated).The thickness of plating is to be not less than 7,5 mm,but may require to be increased at the tank boundariesin regions of high local loading.The section modulus of stiffeners, girders and webs isto be in accordance with Pt 4, Ch 9,8 and Ch 9,9.8 ofthe Rules for Ships.

Peq s k le2

fs γ (ω1 + ω2 + 2)

Peq k

(g) Internal bulkheads (non-perforated).Where a bulkhead may be subjected to an internal pressure head, Peq, resulting from loading on one sideonly, the scantlings of plating, stiffeners and primarymembers are to be determined from (b), (c) and (d).Where no such loading condition is envisaged, thescantlings may be derived as follows:The thickness of plating is to be not less than would berequired for the tank boundary plating at the corresponding tank depth and stiffener spacing,reduced by 0,5 mm. The section modulus of stiffenersand transverses is to be derived from (c) or (d), respec-tively, but Peq need not exceed:

2bar( )

(h) Tank crown structure.Where the minimum thickness of tank boundary plating (7,5 mm) has been adopted, the section modulusof associated stiffeners and transverses are to bederived as above, but Peq is to be not less than thatequivalent to the minimum thickness, that is:

Peq min = ( )2bar

The tank crown plating and stiffeners are also to be suit-able for a head equivalent to the tank test air pressurewhere the tank is to be hydro-pneumatically tested.

(j) Connection of stiffeners to primary supportingmembers.In assessing the arrangement at intersections of continuous secondary and primary members, therequirements of Pt 3, Ch 10,5.2 are to be complied withusing the requirements for ‘other ship types’. The totalload, P, in kN, is to be derived using the internal pressure head, Peq, in bar as given by 4.13.1.4 and thefollowing formulae:(i) In general:

P = 100 (Sw – 0,5s1)s1 Peq kN

(ii) For wash bulkheads:P = 120 (Sw – 0,5s1)s1 Peq kN.

4.21.3 Ultimate design condition

4.21.3.1 For tanks primarily constructed of plane surfaces,the nominal membrane stresses for primary and secondarymembers (stiffeners, web frames, stringers, girders), whencalculated by classical analysis procedures, shall not exceedthe lower of Rm/2,66 or Re/1,33 for nickel steels, carbon-manganese steels, austenitic steels and aluminium alloys,where Rm and Re are defined in 4.18.1.3.However, if detailed calculations are carried out for theprimary members, the equivalent stress σc, as defined in4.18.1.4, may be increased over that indicated above to astress acceptable to LR. Calculations shall take into accountthe effects of bending, shear, axial and torsional deformationas well as the hull/cargo tank interaction forces due to thedeflection of the double bottom and cargo tank bottoms.

4.21.3.2 Tank boundary scantlings shall meet at least therequirements of LR for deep tanks taking into account theinternal pressure as indicated in 4.13.1 and any corrosionallowance required by 4.3.5 or LR 4.3.3.

6,5

0,01265s f k

tp – 1,0

0,01265s f k




Cargo Containment

4.21.3.3 The cargo tank structure shall be reviewed againstpotential buckling.

LR 4.21.3 The effects on the containment system of the10 000 year return period wave loading are to be considered,as follows:• Dynamic cargo pressure loading.• Greatest sloshing pressures distribution.Calculations and analyses are to be performed to show thatthere would be no gross failure of the cargo tanks in thisevent.

4.21.4 Accident design condition

4.21.4.1 The tanks and the tank supports shall be designedfor the accidental loads and design conditions specified in4.3.4.3 and 4.15, as relevant.

4.21.4.2 When subjected to the accidental loads specifiedin 4.15, the stress shall comply with the acceptance criteriaspecified in 4.21.3, modified as appropriate taking intoaccount their lower probability of occurrence.

4.21.5 TestingAll Type A independent tanks shall be subjected to a hydro-static or hydro-pneumatic test.This test shall be performed such that the stresses approximate, as far as practicable, the design stresses, andthat the pressure at the top of the tank corresponds at least tothe MARVS. When a hydro-pneumatic test is performed, theconditions should simulate, as far as practicable, the designloading of the tank and of its support structure includingdynamic components, while avoiding stress levels that couldcause permanent deformation.

LR 4.21.4 The following equations calculate the head ofwater required to model the design pressure, Peq, used in thescantling calculations of the tank structure. If a hydro-pneu-matic test is utilised, the head of water hHP is to be taken as:

hHP = + y

wherehHP = test head of water, in metres, measured from

bottom of cargo tankPeq = design pressure, in bar, at location under

consideration as derived from 4.13.1P = air test pressure, in bar

RD = ρ/ρfreshwaterρ = density of test fluid

ρfreshwater = 1000 kg/m3 at 4°Cy = the vertical distance, in metres, from bottom

of tank to the location under consideration,see Fig. LR 4.2

For a given head of water, hHP, the load, in bar, at the locationunder consideration would be:

PHP,LOAD = P +

Care is to be given that the ratio ≤ 1,0 at any point

around the tank.

PHP,LOAD

10,2Peq

RD (hHP – y)

10,2

10,2 (Peq – P)

RD

If a hydrostatic test is utilised, the head of water, hHS, is to betaken as:

hHS = – (h – y)

wherehHS = test head of water, in metres, measured above top

of cargo tank of depth hh = height of tank as defined in 4.23.1.2 (see also

Fig. LR 4.2)For a given head of water, hHS, the load, in bar, at the location under consideration would be:

PHS,LOAD =

Care is to be given that the ratio at any point

around the tank.The test pressure is to be not less than the MARVS.The design pressure is not to be exceeded at any point, andthe test should adequately load all areas of the tank. See alsoPt 3, Ch 1,8.3.6 in the Rules for Ships. When testing takesplace after installation of the tanks on board the ship unit, careis to be taken that the test head does not result in excessivelocal loading on the hull structure. For this purpose, when thecargo tanks are centrally divided with a non-perforated bulk-head, consideration will be given to testing the port andstarboard sides of the tank independently.

4.22 Type B independent tanks

4.22.1 Design basis

4.22.1.1 Type B independent tanks are tanks designedusing model tests, refined analytical tools and analysis methods to determine stress levels, fatigue life and crackpropagation characteristics. Where such tanks are primarilyconstructed of plane surfaces (prismatic tanks) the designvapour pressure Po shall be less than 0,07 MPa.

4.22.1.2 If the cargo temperature at atmospheric pressureis below –10°C, a partial secondary barrier with a small leakprotection system is required as defined in 4.4. The small leakprotection system shall be designed according to 4.7.

PHP,LOAD

10,2Peq ≤ 1,0

RD [hHS + (h – y)]

10,2

10,2Peq

RD




Locationunder

consideration y

hhHP

hHS

P

Fig. LR 4.2 Hydro-pneumatic tank testing

Cargo Containment


4.22.2.1 The effects of all dynamic and static loads shall beused to determine the suitability of the structure with respectto:• plastic deformation;• buckling;• fatigue failure;• crack propagation.Finite element analysis or similar methods and fracturemechanics analysis or an equivalent approach, shall becarried out.

4.22.2.2 A three-dimensional analysis shall be carried out toevaluate the stress levels, including interaction with the hull ofthe ship unit. The model for this analysis shall include thecargo tank with its supporting and keying system, as well asa reasonable part of the hull.

4.22.2.3 A complete analysis of the particular accelerationsand motions of the ship unit in irregular waves, and of theresponse of the ship unit and its cargo tanks to these forcesand motions shall be performed unless the data is availablefrom similar ship units.

LR 4.22.1(a) Type B independent tanks are to be subjected to a

structural analysis by direct calculation procedures at ahigh confidence level. It is recommended that theassumptions made and the proposed calculation proce-dures be agreed with LR at an early stage. Wherenecessary, model or other tests may be required.

(b) Generally, the scantlings of cargo tanks primarilyconstructed of plane surfaces are not to be less thanrequired by LR 4.21.2 for Type A independent tanks. Inassessing the cumulative effect of the fatigue load,account is to be taken of the quality control aspectssuch as misalignment, distortion, fit-up and weld shape.A 97,7 per cent survival probability S–N curve is to beadopted in association with a cumulative damage factorCw value of 0,1 for primary members and 0,5 forsecondary members. Alternative proposals will bespecially considered.


4.22.3.1 Plastic deformationFor Type B independent tanks, primarily constructed ofbodies of revolution, the allowable stresses shall not exceed:

σm ≤ fσL ≤ 1,5fσb ≤ 1,5FσL+ σb ≤ 1,5Fσm+ σb ≤ 1,5Fσm+ σb+ σg ≤ 3,0FσL + σb+ σg ≤ 3,0F

where:σm = equivalent primary general membrane stressσL = equivalent primary local membrane stressσb = equivalent primary bending stressσg = equivalent secondary stress

f = the lesser of (Rm/A) or (Re/B)F = the lesser of (Rm/C) or (Re/D)

with Rm and Re as defined in 4.18.1.3. With regard to thestresses σm, σL and σb see also the definition of stress categories in 4.27.3. The values A, B, C and D shall have atleast the minimum values shown in Table 4.22.1.For Type B independent tanks, primarily constructed of planesurfaces, the allowable stress levels will be specially considered:The thickness of the skin plate and the size of the stiffenershall not be less than those required for Type A independenttanks.




Table 4.22.1 Factors for determining allowablestress for Type B independent tanks

Nickel steel and carbon Austenitic steels Aluminium alloys

manganese steels

A 3 3,5 4

B 2 1,6 1,5

C 3 3 3

D 1,5 1,5 1,5

aβ = resulting acceleration (static and dynamic) in arbitrary direction βay = transverse component of accelerationaz = vertical component of acceleration

At 0,05L from F.P.

Amidships

C.G. of tankCL

βmax

β

Ellipses

aβ

ay

a z

1,0

aβ

Fig. 4.2 Acceleration ellipse

Cargo Containment

LR 4.22.2 The effects on the containment system of the10 000 year return period wave loading are to be considered,as follows:• Dynamic cargo pressure loading.• Greatest sloshing pressures distribution.Calculations and analysis are to be performed to show thatthere would be no gross failure of the cargo tanks in thisevent.

4.22.3.2 BucklingBuckling strength analyses of cargo tanks subject to externalpressure and other loads causing compressive stresses shallbe carried out in accordance with recognised standards. Themethod should adequately account for the difference in theoretical and actual buckling stress as a result of plate edgemisalignment, lack of straightness or flatness, ovality anddeviation from true circular form over a specified arc or chordlength, as applicable.


4.22.4.1 Fatigue and crack propagation assessment shall beperformed in accordance with the provisions of 4.18.2. Theacceptance criteria shall comply with 4.18.2.7, 4.18.2.8 or4.18.2.9, depending on the detectability of the defect.

4.22.4.2 Fatigue analysis shall consider construction tolerances.

4.22.4.3 Where deemed necessary by the Administration,model tests may be required to determine stress concentra-tion factors and fatigue life of structural elements.


4.22.5.1 The tanks and the tank supports shall be designedfor the accidental loads and design conditions specified in4.3.4.3 and 4.15, as relevant.

4.22.5.2 When subjected to the accidental loads specifiedin 4.15, the stress shall comply with the acceptance criteriaspecified in 4.22.3, modified as appropriate, taking intoaccount their lower probability of occurrence.

4.22.6 TestingType B independent tanks shall be subjected to a hydrostaticor hydro-pneumatic test as follows:• The test shall be performed as required in 4.21.5 for

Type A independent tanks • In addition, the maximum primary membrane stress or

maximum bending stress in primary members under testconditions shall not exceed 90 per cent of the yieldstrength of the material (as fabricated) at the testtemperature. To ensure that this condition is satisfied,when calculations indicate that this stress exceeds 75 per cent of the yield strength the prototype test shallbe monitored by the use of strain gauges or other suitable equipment.

4.22.7 MarkingAny marking of the pressure vessel shall be achieved by amethod that does not cause unacceptable local stress raisers.

4.23 Type C independent tanks

4.23.1 Design basis

4.23.1.1 The design basis for Type C independent tanks isbased on pressure vessel criteria modified to include fracturemechanics and crack propagation criteria. The minimumdesign pressure defined in 4.23.1.2 is intended to ensure thatthe dynamic stress is sufficiently low so that an initial surfaceflaw will not propagate more than half the thickness of theshell during the lifetime of the tank.

4.23.1.2 The design vapour pressure shall not be less than:

Po = 0,2 + AC(ρr)1,5 (MPa)

where:

A = 0,00185 2( )

withσm = design primary membrane stress

∆σA = allowable dynamic membrane stress (double amplitude at probability level Q = 10–8)

= 55 N/mm2 for ferritic-perlitic, martensitic andaustenitic steel

= 25 N/mm2 for aluminium alloy (5083-O)C = a characteristic tank dimension to be taken as the

greatest of the following:h, 0,75b or 0,45l

withh = height of tank (dimension in ship unit’s vertical

direction) (m)b = width of tank (dimension in ship unit’s transverse

direction) (m)l = length of tank (dimension in ship unit’s longitudinal

direction) (m)ρr = the relative density of the cargo (ρr = 1 for fresh

water) at the design temperatureWhen a specified design life of the tank is longer than 108

wave encounters ∆σA shall be modified to give equivalentcrack propagation corresponding to the design life.

LR 4.23.1 Alternative means of calculating the designvapour pressure referred to in 4.23.1.2 will be accepted.

4.23.1.3 The Administration may allocate a tank complyingwith the criteria of Type C, minimum design pressure as in4.23.1.2, to a Type A or Type B, dependent on the configura-tion of the tank and the arrangement of its supports andattachments.

σm

∆σA




Cargo Containment

LR 4.23.2 Before construction of the pressure vessels iscommenced, the following particulars, where applicable, andplans are to be submitted for approval:• Nature of cargoes, together with maximum vapour

pressures and minimum liquid temperature for which thepressure vessels are to be approved, and proposedhydraulic test pressure.

• Particulars of materials proposed for the construction ofthe vessels.

• Particulars of refrigeration equipment.• General arrangement plan showing location of pressure

vessels in the ship unit.• Plans of pressure vessels showing attachments, openings,

dimensions, details of welded joints and particulars ofproposed stress relief heat treatment.

• Plans of seatings, securing arrangements and deck sealingarrangements.

• Plans showing arrangement of mountings, level gaugesand number, type and size of safety valves.

4.23.2 Shell thickness

4.23.2.1 The shell thickness shall be as follows:.1 For pressure vessels, the thickness calculated

according to 4.23.2.4 shall be considered as aminimum thickness after forming, without anynegative tolerance.

.2 For pressure vessels, the minimum thickness ofshell and heads including corrosion allowance,after forming, shall not be less than 5 mm forcarbon-manganese steels and nickel steels, 3 mm for austenitic steels or 7 mm for aluminiumalloys.

.3 The welded joint efficiency factor to be used inthe calculation according to 4.23.2.4 shall be0,95 when the inspection and the non-destruc-tive testing referred to in Chapter 6 are carriedout. This value may be increased up to 1,0 whenaccount is taken of other considerations, such asthe material used, type of joints, welding proce-dure and type of loading. For process pressurevessels LR may accept partial non-destructiveexaminations, but not less than those of Chapter 6, depending on such factors as thematerial used, the design temperature, the nil-ductility transition temperature of the material as fabricated and the type of joint and weldingprocedure, but in this case an efficiency factor ofnot more than 0,85 should be adopted. Forspecial materials the above-mentioned factorsshall be reduced, depending on the specifiedmechanical properties of the welded joint.

4.23.2.2 The design liquid pressure defined in 4.13.1 shallbe taken into account in the internal pressure calculations.

LR 4.23.3 The thickness of pressure parts subject tointernal pressure is to be in accordance with Pt 5, Ch 11 ofthe Rules for Ships except that:(a) the welded joint efficiency factor, J, is to be as defined in

4.23.2.1.3;(b) the allowable stress is to be in accordance with 4.23.3.1; (c) the constant thickness increment (0,75 mm) included in

the formulae in Pt 5, Ch 11,2 of the Rules for Ships mayrequire to be increased in accordance with 4.3.5 or LR 4.3.3.

4.23.2.3 The design external pressure Pe, used for verifyingthe buckling of the pressure vessels, shall not be less thanthat given by:

Pe = P1 + P2 + P3 + P4 (MPa)

whereP1 = setting value of vacuum relief valves. For vessels

not fitted with vacuum relief valves P1 shall bespecially considered, but shall not in general betaken as less than 0,025 MPa

P2 = the set pressure of the pressure relief valves (PRVs)for completely closed spaces containing pressurevessels or parts of pressure vessels; elsewhere P2 = 0

P3 = compressive actions in or on the shell due to theweight and contraction of thermal insulation, weightof shell including corrosion allowance and othermiscellaneous external pressure loads to which thepressure vessel may be subjected. These include,but are not limited to, weight of domes, weight oftowers and piping, effect of product in the partiallyfilled condition, accelerations and hull deflection. Inaddition, the local effect of external or internal pressures or both shall be taken into account

P4 = external pressure due to head of water for pressurevessels or part of pressure vessels on exposeddecks; elsewhere P4 = 0.

4.23.2.4 Scantlings based on internal pressure shall becalculated as follows:The thickness and form of pressure-containing parts of pressure vessels, under internal pressure, as defined in4.13.1, including flanges, should be determined. These calculations shall in all cases be based on accepted pressurevessel design theory. Openings in pressure-containing partsof pressure vessels shall be reinforced in accordance withrecognised Standards.

4.23.2.5 Stress analysis in respect of static and dynamicloads shall be performed as follows:

.1 Pressure vessel scantlings shall be determined inaccordance with 4.23.2.4.

.2 Calculations of the loads and stresses in way ofthe supports and the shell attachment of thesupport shall be made. Loads referred to in 4.12to 4.15 shall be used, as applicable. Stresses inway of the supporting structures shall be to arecognised standard acceptable to LR. In specialcases a fatigue analysis may be required by LR.

.3 If required by LR, secondary stresses and thermal stresses shall be specially considered.




Cargo Containment


4.23.3.1 Plastic deformationFor Type C independent tanks, the allowable stresses shallnot exceed:

σm ≤ fσL ≤ 1,5fσb ≤ 1,5fσL + σb ≤ 1,5fσm + σb ≤1,5fσm + σb+ σg ≤ 3,0fσL + σb+ σg ≤ 3,0f

whereσm = equivalent primary general membrane stressσL = equivalent primary local membrane stressσb = equivalent primary bending stressσg = equivalent secondary stress

f = the lesser of (Rm/A) or (Re/B)with Rm and Re as defined in 4.18.1.3. With regard to thestresses σm, σL, σb and σg see also the definition of stresscategories in 4.27.3. The values A and B shall have at leastthe minimum values shown in Table 4.23.1.

LR 4.23.4 The effects on the containment system of the10 000 year return period wave loading are to be considered,as follows:• Dynamic cargo pressure loading.• Greatest sloshing pressures distribution.Calculations and analysis are to be performed to show thatthere would be no failure of, or leakage from, the pressurevessels in this event.

4.23.3.2 Buckling criteria shall be as follows:The thickness and form of pressure vessels subject to externalpressure and other loads causing compressive stresses shallbe based on calculations using accepted pressure vesselbuckling theory and shall adequately account for the difference in theoretical and actual buckling stress as a resultof plate edge misalignment, ovality and deviation from truecircular form over a specified arc or chord length.

4.23.4 Fatigue design conditionFor large Type C independent tanks where the cargo at atmospheric pressure is below –55°C, LR may require additional verification to check their compliance with 4.23.1.1,regarding static and dynamic stress.


4.23.5.1 The tanks and the tank supporting structures shallbe designed for the accidental loads and design conditionsspecified in 4.3.4.3 and 4.15, as relevant.

4.23.5.2 When subjected to the accidental loads specifiedin 4.15, the stress shall comply with the acceptance criteriaspecified in 4.23.3.1, modified as appropriate taking intoaccount their lower probability of occurrence.

4.23.6 Testing

4.23.6.1 Each pressure vessel shall be subjected to a hydro-static test at a pressure measured at the top of the tanks, ofnot less than 1,5 Po. In no case during the pressure test shallthe calculated primary membrane stress at any point exceed90 per cent of the yield stress of the material. To ensure thatthis condition is satisfied where calculations indicate that thisstress will exceed 0,75 times the yield strength, the prototypetest shall be monitored by the use of strain gauges or othersuitable equipment in pressure vessels other than simplecylindrical and spherical pressure vessels.

4.23.6.2 The temperature of the water used for the test shallbe at least 30°C above the nil-ductility transition temperatureof the material, as fabricated.

4.23.6.3 The pressure shall be held for 2 hours per 25 mm ofthickness, but in no case less than 2 hours.

4.23.6.4 Where necessary for cargo pressure vessels, ahydro-pneumatic test may be carried out under the conditionsprescribed in 4.23.6.1 to 4.23.6.3.

LR 4.23.5 When a hydro-pneumatic test is performed, theconditions are to simulate, so far as practicable, the actualloading of the tank and its supports.

4.23.6.5 Special consideration may be given to the testingof tanks in which higher allowable stresses are used, dependingon service temperature. However, the requirements of4.23.6.1 shall be fully complied with.

4.23.6.6 After completion and assembly, each pressurevessel and its related fittings shall be subjected to anadequate tightness test, which may be performed in combination with the pressure testing referred to in 4.22.6.1.

4.23.6.7 Pneumatic testing of pressure vessels other thancargo tanks shall only be considered on an individual casebasis. Such testing shall only be permitted for those vesselsdesigned or supported such that they cannot be safely filledwith water, or for those vessels that cannot be dried and areto be used in a service where traces of the testing mediumcannot be tolerated.

4.23.7 MarkingThe required marking of the pressure vessel shall be achievedby a method that does not cause unacceptable local stressraisers.




Table 4.23.1 Factors for determining allowablestress for Type C independent tanks

Nickel steelsand carbon- Austenitic steels Aluminium alloys

manganese steels

A 3 3,5 4

B 1,5 1,5 1,5

Cargo Containment

4.24 Membrane tanks

4.24.1 Design basis

4.24.1.1 The design basis for membrane containmentsystems is that thermal and other expansion or contraction iscompensated for without undue risk of losing the tightness ofthe membrane.

4.24.1.2 A systematic approach, based on analysis andtesting, shall be used to demonstrate that the system willprovide its intended function in consideration of the identifiedin service events as specified in 4.24.2.1.

4.24.1.3 If the cargo temperature at atmospheric pressureis below –10°C a complete secondary barrier is required asdefined in 4.5. The secondary barrier shall be designedaccording to 4.6.

4.24.1.4 The design vapour pressure Po shall not normallyexceed 0,025 MPa. If the hull scantlings are increasedaccordingly and consideration is given, where appropriate, tothe strength of the supporting thermal insulation, Po may beincreased to a higher value but less than 0,07 MPa.

4.24.1.5 The definition of membrane tanks does not excludedesigns such as those in which non-metallic membranes areused or where membranes are included or incorporated intothe thermal insulation.

4.24.1.6 The thickness of the membranes is normally not toexceed 10 mm.

4.24.1.7 The circulation of inert gas throughout the primaryinsulation space and the secondary insulation space, inaccordance with 9.2.1, shall be sufficient to allow for effective means of gas detection.

4.24.2 Design considerations

4.24.2.1 Potential incidents that could lead to loss of fluidtightness over the life of the membranes shall be evaluated.These include, but are not limited to:

.1 Ultimate design events• Tensile failure of membranes.• Compressive collapse of thermal insulation.• Thermal ageing.• Loss of attachment between thermal

insulation and hull structure.• Loss of attachment of membranes to

thermal insulation system.• Structural integrity of internal structures

and their supports.• Failure of the supporting hull structure.

.2 Fatigue design events• Fatigue of membranes including joints and

attachments to hull structure.• Fatigue cracking of thermal insulation.• Fatigue of internal structures and their

supports.• Fatigue cracking of inner hull leading to

ballast water ingress.

.3 Accident design events• Accidental mechanical damage (such as

dropped objects inside the tank while inservice).

• Accidental over-pressurisation of thermal insulation spaces.

• Accidental vacuum in the tank.• Water ingress through the inner hull structure.

Designs where a single internal event could cause simultaneousor cascading failure of both membranes are unacceptable.

4.24.2.2 The necessary physical properties (mechanical,thermal, chemical, etc.) of the materials used in the construc-tion of the cargo containment system shall be establishedduring the design development in accordance with 4.24.1.2.

4.24.3 Loads, load combinationsParticular consideration shall be paid to the possible loss oftank integrity due to either an overpressure in the interbarrierspace, a possible vacuum in the cargo tank, the sloshingeffects, to hull vibration effects, or any combination of theseevents.

4.24.4 Structural analyses

4.24.4.1 Structural analyses and/or testing for the purposeof determining the ultimate strength and fatigue assessmentsof the cargo containment and associated structures, e.g.,structures as defined in 4.9 shall be performed. The structuralanalysis shall provide the data required to assess each failuremode that has been identified as critical for the cargo contain-ment system.

4.24.4.2 Structural analyses of the hull shall take intoaccount the internal pressure as indicated in 4.13.1. Specialattention shall be paid to deflections of the hull and theircompatibility with the membrane and associated thermalinsulation.

4.24.4.3 The analyses referred to in 4.24.4.1 and 4.24.4.2shall be based on the particular motions, accelerations andresponse of ship units and cargo containment systems.

LR 4.24.1 The hull structure supporting the membranetank is to be incorporated into the structural finite elementmodel of the ship unit. The scantlings of the inner hull are tobe not less than required by Part 10.

LR 4.24.2 Strength analysis is also to be carried out forstructures inside the tank, i.e., pump towers, and its attachments. This should take account of hydrodynamicloads due to the sloshing motion of the cargo, inertia loading due to the accelerations of the vessel, and thermaleffects due to loading and unloading of the tanks in accor-dance with the operational philosophy. The assessment is toconsider stress levels, including shear stresses in the welds,buckling, fatigue (including fatigue due to thermal effects), andvibration.


4.24.5.1 The structural resistance of every critical compo-nent, sub-system, or assembly, shall be established, inaccordance with 4.24.1.2, for in-service conditions.




Cargo Containment

4.24.5.2 The choice of strength acceptance criteria for thefailure modes of the cargo containment system, its attach-ments to the hull structure and internal tank structures, shallreflect the consequences associated with the consideredmode of failure.

4.24.5.3 The inner hull scantlings shall meet the require-ments for deep tanks, taking into account the internalpressure as indicated in 4.13.1 and the specified appropriaterequirements for sloshing load as defined in 4.14.3.

LR 4.24.3 The effects on the containment system of the10 000 year return period wave loading are to be considered,as follows:• Hull girder interaction loading.• Greatest sloshing pressures distribution.Calculations and analyses are to be performed to show thateither the primary barrier or the secondary barrier should beexpected to remain liquid tight in this event.


4.24.6.1 Fatigue analysis shall be carried out for structuresinside the tank, i.e. pump towers, and for parts of membraneand pump tower attachments, where failure developmentcannot be reliably detected by continuous monitoring.

4.24.6.2 The fatigue calculations shall be carried out inaccordance with 4.18.2, with relevant requirements dependingon:• The significance of the structural components with

respect to structural integrity.• Availability for inspection.

4.24.6.3 For structural elements for which it can be demon-strated by tests and/or analyses that a crack will not developto cause simultaneous or cascading failure of bothmembranes, Cw shall be less than or equal to 0,5.

4.24.6.4 Structural elements subject to periodic inspection,and where an unattended fatigue crack can develop to causesimultaneous or cascading failure of both membranes, shallsatisfy the fatigue and fracture mechanics requirementsstated in 4.18.2.8.

4.24.6.5 Structural elements not accessible for in-serviceinspection, and where a fatigue crack can develop withoutwarning to cause simultaneous or cascading failure of bothmembranes, shall satisfy the fatigue and fracture mechanicsrequirements stated in 4.18.2.9.

LR 4.24.4 Selected details of the containment systemare to be investigated by fatigue analysis, which should takeinto account interactions with the vessel-supporting structureof the ship unit, including local, transverse and longitudinalhull girder effects, also pressure loading from the cargo andfrom ballast acting on the supporting structure. The number ofcycles of full and partial loading and unloading are to beconsistent with the operational philosophy of the unit. Forinvestigation of the fatigue damage sustained by thesecondary barrier following failure of the primary barrier, asimplified load distribution over a period of 15 days may beused, unless different project-specific requirements apply, asdescribed in 4.6.2.1. Project-specific requirements are to besubmitted for consideration.

LR 4.24.5 The fatigue damage factor of both thecontainment system and internal structures such as pumptowers is generally to be no greater than 0,5, but is to be nogreater than 0,1 for any structural detail which is not accessible for survey during the service life of the vessel andwhose failure would cause the simultaneous breach of boththe primary and secondary barrier, such as the attachmentweld of the pump tower base support.


4.24.7.1 The containment system and the supporting hullstructure shall be designed for the accidental loads specifiedin 4.15. These loads need not be combined with each otheror with environmental loads.

4.24.7.2 Additional relevant accident scenarios shall bedetermined based on a risk analysis. Particular attention shallbe paid to securing devices inside of tanks.

4.24.8 Design development testing

4.24.8.1 The design development testing required in4.24.1.2 should include a series of analytical and physicalmodels of both the primary and secondary barriers, includingcorners and joints, tested to verify that they will withstand theexpected combined strains due to static, dynamic and thermal loads. This will culminate in the construction of aprototype scaled model of the complete cargo containmentsystem.Testing conditions considered in the analytical and physicalmodel shall represent the most extreme service conditions thecargo containment system will be likely to encounter over itslife.Proposed acceptance criteria for periodic testing ofsecondary barriers required in 4.6.2 is to be based on theresults of testing carried out on the prototype scaled model.

4.24.8.2 The fatigue performance of the membrane materialsand representative welded or bonded joints in the membranesshall be determined by tests.The ultimate strength and fatigue performance of arrange-ments for securing the thermal insulation system to the hullstructure shall be determined by analyses or tests.




Cargo Containment

4.24.9 TestingIn ship units fitted with membrane cargo containmentsystems, all tanks and other spaces that may normally containliquid and are adjacent to the hull structure supporting themembrane, shall be hydrostatically tested.All hold structures supporting the membrane shall be testedfor tightness before installation of the cargo containmentsystem.Pipe tunnels and other compartments that do not normallycontain liquid need not be hydrostatically tested.

4.25 Integral tanks

4.25.1 Design basisIntegral tanks that form a structural part of the hull and areaffected by the loads that stress the adjacent hull structureshall comply with the following:

.1 The design vapour pressure Po as defined in4.1.2 shall not normally exceed 0,025 MPa. If thehull scantlings are increased accordingly, Po maybe increased to a higher value, but less than 0,07 MPa.

.2 Integral tanks may be used for products providedthe boiling point of the cargo is not below –10°C.A lower temperature may be accepted by LRsubject to special consideration, but in suchcases a complete secondary barrier shall beprovided.


LR 4.25.1 Integral tanks are to be designed andconstructed in accordance with the requirements for cargotanks in Part 10, using the actual cargo density and additional vapour pressure.


LR 4.25.2 The effects of 10 000 year return period waveloading on the containment system are to be considered. Thisis to include:• Hull girder loading.• Dynamic cargo pressure loading.• Greatest sloshing pressures distribution.Calculations and analyses are to be performed to show thatthere would be no gross failure of the cargo tanks in thisevent.


4.25.4.1 The tanks and the tank supports shall be designedfor the accidental loads specified in 4.15, as relevant.

4.25.5 TestingAll integral tanks shall be hydrostatically or hydro-pneumati-cally tested. The test shall be performed so that the stressesapproximate, as far as practicable, to the design stresses andthat the pressure at the top of the tank corresponds at least tothe MARVS.

4.26 Semi-membrane tanks

4.26.1 Design basis

4.26.1.1 Semi-membrane tanks are non-self-supportingtanks when in the loaded condition and consist of a layer,parts of which are supported through thermal insulation bythe adjacent hull structure; the rounded parts of this layerconnecting the above-mentioned supported parts aredesigned also to accommodate the thermal and other expansion or contraction.

4.26.1.2 The design vapour pressure Po shall not normallyexceed 0,025 MPa. If the hull scantlings are increasedaccordingly, and consideration is given, where appropriate, tothe strength of the supporting thermal insulation, Po may beincreased to a higher value but less than 0,07 MPa.

4.26.1.3 For semi-membrane tanks the relevant require-ments in this Section for independent tanks or for membranetanks shall be applied as appropriate.

LR 4.26.1 A structural analysis and other analyses andcalculations should be performed in accordance with therequirements for membrane tanks or independent tanks asappropriate, taking into account the internal pressure as indicated in 4.13.1.

4.26.1.4 In the case of semi-membrane tanks that complyin all respects with the requirements applicable to Type Bindependent tanks, except for the manner of support, theAdministration may, after special consideration, accept apartial secondary barrier.

Part F Guidance

4.27 Guidance Notes for Chapter 4

4.27.1 Guidance to detailed calculation of internal pressure for static design purpose

4.27.1.1 This Section provides guidance for the calculationof the associated dynamic liquid pressure for the purpose ofstatic design calculations. This pressure may be used fordetermining the internal pressure given in 4.13.1.4.Pgd is the associated maximum liquid pressure determinedusing site-specific accelerations.Peq is to be calculated as follows:

Peq= Po + Pgd (MPa)




LR 4.27.1 See also Fig. LR 4.3.

LR 4.27.2 Accelerations in three dimensions are to beconsidered for ship units with independent spherical Type Btanks for which the ellipsoid as shown in Fig. 4.4 is to beused. Where loading conditions are proposed including oneor more partially filled tanks, the internal liquid pressure to beused will be specially considered. See also 4.14.3.

4.27.1.3 Equivalent calculation procedures may be applied.

4.27.2 Guidance formulae for acceleration components

LR 4.27.3 The following formulae are given as guidancefor the determination of the maximum value of internal liquidpressure head Pgd, (see 4.27.1, internal pressure).In the transverse direction, as shown in Fig. 4.2, the followingapply:

aβ =

The range of angle β is:

0 to βmax, with βmax = arc tan

For the longitudinal direction, βmax and aβ are to be determined with ax substituted for ay.

ay

(1 – az2 )0,5

cos β.ay2 + az.ay (cos2 β.ay

2 + sin2 β.az2 – sin2 β)0,5

(cos2 β.ay2 + sin2 β.az

2)

Cargo Containment

4.27.1.2 The internal liquid pressures are those created bythe resulting acceleration of the centre of gravity of the cargodue to the motions of the ship unit referred to in 4.14.1. Thevalue of internal liquid pressure Pgd resulting from combinedeffects of gravity and dynamic accelerations shall be calculated as follows:

Pgd = αβ Zβ MPa( )where

αβ = dimensionless acceleration (i.e. relative to theacceleration of gravity), resulting from gravitationaland dynamic loads, in an arbitrary direction β, (seeFig. 4.2)Note for large tanks an acceleration ellipsoid, takingaccount of transverse vertical and longitudinalaccelerations should be used

Z = largest liquid height (in metres) above the pointwhere the pressure is to be determined measuredfrom the tank shell in the β direction (see Fig. 4.3)Tank domes considered to be part of the acceptedtotal tank volume shall be taken into account whendetermining Zβ unless the total volume of tankdomes Vd does not exceed the following value:

Vd = Vt ( )where

Vt = tank volume without any domesFL = filling limit according to Chapter 15

ρ = maximum cargo density (kg/m3) at the designtemperature

The direction that gives the maximum value of Pgd shall beconsidered. Where acceleration components in three directions need to be considered, the ellipsoid shown in Fig. 4.4 shall be used instead of the ellipse in Fig. 4.2. Theabove formula applies only to full tanks.

100 – FL

FL

ρ1,02 x 105




Z

Y

90º

90º

β

aβ

Zβ

(Yp, Zp)Pressure point

Fig. 4.3 Determination of internal pressure heads

Pressure point being considered

Y

h

Z

90º

Zβ

β

Z β

Highest point of tank at angle β (see Note)

NOTESmall tank domes not considered to be part of the acceptedtotal volume of the cargo tank need not be considered when determining Zβ

Fig. LR 4.3 Determination of internal pressure heads

Cargo Containment

4.27.3 Stress categories

4.27.3.1 For the purpose of stress evaluation, stress categories are defined in this Section.

4.27.3.2 Normal stress is the component of stress normalto the plane of reference.

4.27.3.3 Membrane stress is the component of normalstress that is uniformly distributed and equal to the averagevalue of the stress across the thickness of the section underconsideration.

4.27.3.4 Bending stress is the variable stress across thethickness of the section under consideration, after thesubtraction of the membrane stress.

4.27.3.5 Shear stress is the component of the stress actingin the plane of reference.

4.27.3.6 Primary stress is a stress produced by theimposed loading, which is necessary to balance the externalforces and moments. The basic characteristic of a primarystress is that it is not self-limiting. Primary stresses thatconsiderably exceed the yield strength will result in failure or atleast in gross deformations.

4.27.3.7 Primary general membrane stress is a primarymembrane stress that is so distributed in the structure thatno redistribution of load occurs as a result of yielding.

4.27.3.8 Primary local membrane stress arises where amembrane stress produced by pressure or other mechanicalloading and associated with a primary or a discontinuity effectproduces excessive distortion in the transfer of loads for otherportions of the structure. Such a stress is classified as aprimary local membrane stress, although it has some characteristics of a secondary stress. A stress region may beconsidered as local if:

S1 ≤ 0,5 and

S2 ≥ 2,5

where:S1 = distance in the meridional direction over which the

equivalent stress exceeds 1,1fS2 = distance in the meridional direction to another

region where the limits for primary generalmembrane stress are exceeded

R = mean radius of the vesselt = wall thickness of the vessel at the location where

the primary general membrane stress limit isexceeded

f = allowable primary general membrane stress.

Rt

Rt




TYPICAL MIDSHIP TANK

TYPICAL FORWARD TANK

aβ = resulting acceleration in arbitrary direction βaX = longitudinal component of accelerationaY = transverse component of acceleration aZ = vertical component of acceleration

CL CLC.G. of tankC.G. of tank

βmax Y

βmax X

aβ

aβ

aY

aβ

a Z

aX1,

0

βmax Y

βmax X

aX

a Z

aβ

aY

aβaβ

Fig. 4.4 Acceleration ellipsoids

Cargo Containment

4.27.3.9 Secondary stress is a normal stress or shearstress developed by constraints of adjacent parts or by self-constraint of a structure. The basic characteristic of asecondary stress is that it is self-limiting. Local yielding andminor distortions can satisfy the conditions that cause thestress to occur.




Document1 12/04/02 15:23 Page 1

Process Pressure Vessels and Liquids, Vapour andPressure Piping Systems

Section

5.1 General

5.2 System requirements

5.3 Arrangements for cargo piping outside thecargo area

5.4 Design pressure

5.5 Cargo system valve requirements

5.6 Cargo transfer arrangements

5.7 Installation requirements

5.8 Piping fabrication and joining details

5.9 Welding, post-weld heat treatment and non-destructive testing

5.10 Installation requirements for cargo pipingoutside the cargo area

5.11 Piping system component requirements

5.12 Materials

5.13 Testing requirements

5.1 General

5.1.1 The requirements of this Chapter apply to productsand process piping, including vapour piping, gas fuel pipingand vent lines of safety valves or similar piping. Auxiliary pipingsystems not containing cargo are exempt from the generalrequirements of this Chapter.

5.1.2 The requirements for Type C independent tanksprovided in Chapter 4 may also apply to process pressurevessels. If so required, the term ‘pressure vessels’ as used inChapter 4, covers both Type C independent tanks andprocess pressure vessels.

5.1.3 Process pressure vessels include surge tanks, heatexchangers and accumulators that store or treat liquid orvapour cargo.

5.2 System requirements

The cargo handling and cargo control systems shall bedesigned taking into account the following:• Prevention of an abnormal condition escalating to a

release of liquid or vapour cargo;• The safe collection and disposal of cargo fluids released;• Prevention of the formation of flammable mixtures;

• Prevention of ignition of flammable liquids or gases andvapours released;

• Limiting the exposure of personnel to fire and otherhazards.

5.2.1 Arrangements – General

5.2.1.1 Any piping system that may contain cargo liquid orvapour shall:• be segregated from other piping systems, except where

interconnections are required for cargo related opera-tions such as purging, gas freeing or inerting. Therequirements of 9.4.4 shall be taken into account withregard to preventing back flow of cargo. In such cases,precautions shall be taken to ensure that cargo or cargovapour cannot enter other piping systems through theinterconnections;

• except as provided in Chapter 16, not pass through anyaccommodation space, service space or control stationor through a machinery space other than a cargomachinery space;

• be connected to the cargo containment system directlyfrom the weather decks except where pipes installed ina vertical trunkway or equivalent are used to traversevoid spaces above a cargo containment system andexcept where pipes for drainage, venting or purgingtraverse cofferdams;

• be located in the cargo area above the weather deckexcept for bow or stern loading and unloading arrange-ments in accordance with 3.8, emergency cargojettisoning piping systems in accordance with 5.3.1,turret compartment systems in accordance with 5.3.3and except in accordance with Chapter 16; and

• be located inboard of the transverse tank locationrequirements of 2.4.1 except for emergency cargo jettisoning piping systems.

5.2.1.2 Suitable means shall be provided to relieve the pressure and remove liquid cargo from discharging headers;likewise, any piping between the outermost discharge valvesand loading arms or cargo hoses or any other location prior tothe outermost valve that may be subject to pressurisationduring discharging operations.

5.2.1.3 Piping systems carrying fluids for direct heating orcooling of cargo shall not be led outside the cargo area unlessa suitable means is provided to prevent or detect the migrationof cargo vapour outside the cargo area. (See also 13.6.2.6).

5.2.1.4 Relief valves discharging liquid cargo from thepiping system shall discharge into the cargo tanks.Alternatively, they may discharge to the flare system which isto be designed in accordance with API 521 Guide forPressure-relieving and Depressuring Systems: Petroleumpetrochemical and natural gas industries-Pressure relievingand depressuring systems. Where required to prevent over-pressure in downstream piping, relief valves on cargo pumpsshall discharge to the pump suction.





5.3 Arrangements for cargo piping outside thecargo area

5.3.1 Emergency cargo jettisoningIf fitted, an emergency cargo jettisoning piping system shallcomply with 5.2.1 as appropriate and may be led aft, externalto accommodation spaces, service spaces or control stationsor machinery spaces, but shall not pass through them. If anemergency cargo jettisoning piping system is permanentlyinstalled, a suitable means of isolating the piping system fromthe cargo piping shall be provided within the cargo area.

5.3.2 Bow and stern loading arrangementsSubject to the requirements of 3.8, this Section and 5.10.1,cargo piping may be arranged to permit bow or stern loadingand unloading.

1. Arrangements shall be made to allow such pipingto be purged and gas freed after use. When notin use the spool pieces shall be removed and thepipe ends blank flanged. The vent pipesconnected with the purge shall be located in thecargo area.

5.3.3 Turret compartment transfer systems For the transfer of liquid or vapour cargo through an internalturret arrangement located, outside the cargo area, the pipingserving this purpose shall comply with 5.2.1 as applicable,5.10.2 and the following;

.1 Piping shall be located above the weather deckexcept for the connection to the turret.

.2 Portable arrangements shall not be permitted.

.3 Arrangements shall be made to allow such pipingto be purged and gas freed after use. When notin use the spool pieces for isolation from thecargo piping shall be removed and the pipe endsblank flanged. The vent pipes connected with thepurge shall be located in the cargo area.

5.3.4 Gas fuel piping systemsGas fuel piping in machinery spaces shall comply with allapplicable Sections of this Chapter in addition to the require-ments of Chapter 16.

5.4 Design pressure

5.4.1 The design pressure Po, used to determine minimumscantlings of piping and piping system components, shall benot less than the maximum gauge pressure to which thesystem may be subjected in service. The minimum designpressure used shall not be less than 1 MPa except for; openended lines or pressure relief valve discharge lines where itshall be not less than the lower of 0,5 MPa, or 10 times therelief valve set pressure.

5.4.2 The greater of the following design conditions shallbe used for piping, piping systems and components, basedon the cargoes being carried:

.1 for vapour piping systems or components thatmay be separated from their relief valves andwhich may contain some liquid: the saturatedvapour pressure at a design temperature of45°C. Higher or lower values may be used (see4.13.1.2); or

.2 for systems or components that may be sepa-rated from their relief valves and which containonly vapour at all times: the superheated vapourpressure at 45°C. Higher or lower values may beused, see 4.13.1.2, assuming an initial conditionof saturated vapour in the system at the systemoperating pressure and temperature; or

.3 the MARVS of the cargo tanks and cargoprocessing systems; or

.4 the pressure setting of the associated pump orcompressor discharge relief valve; or

.5 the maximum total discharge or loading head ofthe cargo piping system considering all possiblepumping arrangements or the relief valve settingon a pipeline system.

5.4.3 Those parts of the liquid piping systems that maybe subjected to surge pressures shall be designed to with-stand this pressure.

5.4.4 The design pressure of the outer pipe or duct ofgas fuel systems shall not be less than the maximum workingpressure of the inner gas pipe. Alternatively for gas fuel pipingsystems with a working pressure greater than 1 MPa, thedesign pressure of the outer duct shall not be less than themaximum built-up pressure arising in the annular spaceconsidering the local instantaneous peak pressure in way ofany rupture and the ventilation arrangements.

5.5 Cargo system valve requirements

Every cargo tank and piping system shall be fitted with manually-operated valves for isolation purposes as specifiedin this Section.In addition, remotely operated valves shall also be fitted, asappropriate, as part of the emergency shut-down (ESD)system. The purpose of this ESD system is to stop cargo flowor leakage in the event of an emergency when cargo liquid orvapour transfer is in progress.The ESD system is intended to return the cargo system to asafe static condition so that any remedial action can be taken.Due regard shall be given in the design of the ESD system toavoid the generation of surge pressures within the cargotransfer pipework.The equipment to be shut down on ESD activation includes;manifold valves during loading or discharge, any pump orcompressor etc transferring cargo internally or externally (e.g.to a shuttle tanker) plus cargo tank valves if the MARVSexceeds 0,07 MPa.



LLOYD’S REGISTER2

5.6.3 Vapour return connectionsConnections for vapour return from the shuttle tanker to theship unit shall be provided.

5.6.4 Cargo tank vent piping systemsThe pressure relief system shall be connected to a vent pipingsystem designed to minimise the possibility of cargo vapouraccumulating on the decks, or entering accommodationspaces, service spaces, control stations and machineryspaces, or other spaces where it may create a dangerouscondition.

5.6.5 Cargo sampling connections

5.6.5.1 Connections to cargo piping systems for takingcargo liquid samples shall be clearly marked and shall bedesigned to minimise the release of cargo vapours.

5.6.5.2 Liquid sampling systems shall be provided with twovalves on the sample inlet. One of these valves shall be of themulti-turn type to avoid accidental opening, and shall bespaced far enough apart to ensure that they can isolate theline if there is blockage, by ice or hydrates for example.

5.6.5.3 On closed loop systems, the valves on the returnpipe shall also comply with 5.6.5.2.

5.6.5.4 The connection to the sample container shallcomply with a recognised Standard and be supported so asto be able to support the weight of a sample container.Threaded connections shall be tack-welded, or otherwiselocked, to prevent them being unscrewed during the normalconnection and disconnection of sample containers. Thesample connection shall be fitted with a closure plug or flangeto prevent any leakage when the connection is not in use.

5.6.5.5 Sample connections used only for vapour samplesmay be fitted with a single valve in accordance with 5.5, 5.8and 5.13, and shall also be fitted with a closure plug or flange.

5.6.5.6 Sampling operations shall be undertaken as in18.9.

5.6.6 Cargo filters It is anticipated that liquefied gas facilities will remove contaminants before liquefaction. In the event that furtherfiltration is anticipated, e.g., cool down during commissioning,the following shall be applied.The cargo liquid and vapour systems shall be capable ofbeing fitted with filters to protect against damage by foreignobjects. Such filters may be permanent or temporary, and thestandards of filtration shall be appropriate to the risk of debris,etc., entering the cargo system. Means shall be provided toindicate that filters are becoming blocked. Means shall beprovided to isolate, depressurise and clean the filters safely.


5.5.1 Cargo tank connectionsAll liquid and vapour connections, except for safety reliefvalves and liquid level gauging devices, shall have shut-offvalves located as close to the tank as practicable. Thesevalves shall provide full closure and shall be capable of localmanual operation; they may also be capable of remote operation.For cargo tanks with a MARVS exceeding 0,07 MPa, theabove connections shall also be equipped with remotelycontrolled ESD valves. These valves shall be located as closeto the tank as practicable. A single valve may be substitutedfor the two separate valves provided the valve complies withthe requirements of 18.10.2 and provides full closure of theline.

5.5.2 Cargo offloading connectionsThe offloading station is to provide a remotely controlled ESDvalve prior to the hose connection to prevent liquid andvapour to or from the facility in the event of an incident. In theevent that one or more transfer hoses are not used a manualand controlled by permit (or similar method) stop valve is tobe provided prior to the hose connection.In the event that the vapour return line is closed the ESDsystem is to be designed to stop all cargo pumping.If the cargo tank MARVS exceeds 0,07 MPa an additionalmanual valve shall be provided for each transfer connection inuse, and may be inboard or outboard of the ESD valve to suitthe design of the ship unit.

5.5.3 Cargo tank connections for gauging or measuringdevices need not be equipped with excess flow valves or ESDvalves provided that the devices are constructed so that theoutward flow of tank contents cannot exceed that passed bya 1,5 mm diameter circular hole.

5.5.4 All pipelines or components which may be isolatedin a liquid full condition shall be protected with relief valves forthermal expansion and evaporation.

5.5.5 All pipelines or components which may be isolatedautomatically due to a fire with a liquid volume of more than0,05 m3 entrapped shall be provided with PRVs sized for afire condition.

5.6 Cargo transfer arrangements

5.6.1 Where cargo transfer is by means of cargo pumpsthat are not accessible for repair with the tanks in service, atleast two separate means shall be provided to transfer cargofrom each cargo tank and the design shall be such that failureof one cargo pump or means of transfer will not prevent thecargo transfer by another pump or pumps, or other cargotransfer means.

5.6.2 The procedure for transfer of cargo by gas pressurisation shall preclude lifting of the relief valves duringsuch transfer. Gas pressurisation may be accepted as ameans of transfer of cargo for those tanks where the designfactor of safety is not reduced under the conditions prevailingduring the cargo transfer operation. If the cargo tank reliefvalves or set pressure are changed for this purpose, as ispermitted in accordance with 8.2.7 and 8.2.8 the new setpressure is not to exceed Ph as is defined in 4.13.1.





5.7 Installation requirements

5.7.1 Design for expansion and contractionProvision shall be made to protect the piping, piping systemand components and cargo tanks from excessive stressesdue to thermal movement and from movements of the tankand hull structure. The preferred method outside the cargotanks is by means of offsets, bends or loops, but multi-layerbellows may be used if offsets, bends or loops are not practicable.

5.7.2 Precautions against low temperatureLow temperature piping shall be thermally isolated from theadjacent hull structure, where necessary, to prevent thetemperature of the hull from falling below the design temper-ature of the hull material. Where liquid piping is dismantledregularly, or where liquid leakage may be anticipated, such asat cargo transfer connections and at pump seals, protectionfor the hull beneath shall be provided.

5.7.3 Cryogenic protectionCryogenic protection against spills is to be provided fortemperatures below –110°C, such systems are to provideadequate coverage of hull, main decks, process decks,process support structures and other vulnerable equipmentwithin the process area. These systems are to considerspillage, cryogenic jets and cryogenic pooling, and their sizeand scope are to be based on the process area inventoriesof the cryogenic material. The design of such systems is toensure that they are constantly available and not reactive toan event.Areas of the facility used for the discharge of cryogenic material may employ a water curtain for protection duringsuch operations and is additional to the requirements of11.3.1.4.

5.7.4 BondingWhere tanks or cargo piping and piping equipment are separated from the structure of the ship unit by thermal isolation, provision shall be made for electrically bonding boththe piping and the tanks. All gasketed pipe joints and hoseconnections shall be electrically bonded. Except where bonding straps are used, it shall be demonstrated that theelectrical resistance of each joint or connection is less than 1 MΩ.

5.8 Piping fabrication and joining details

5.8.1 GeneralThe requirements of this Section apply to piping inside andoutside the cargo tanks. Relaxation from these requirementsmay be accepted, in accordance with recognised Standardsfor piping inside cargo tanks and open-ended piping.

5.8.2 Direct connectionsThe following direct connection of pipe lengths, withoutflanges, may be considered:

.1 Butt welded joints with complete penetration atthe root may be used in all applications. Fordesign temperatures colder than –10°C, buttwelds shall be either double welded or equivalentto a double welded butt joint. This may beaccomplished by use of a backing ring, consum-able insert or inert gas back up on the first pass.For design pressures in excess of 1 MPa anddesign temperatures of –10°C or colder, backingrings shall be removed.

.2 Slip-on welded joints with sleeves and relatedwelding, having dimensions in accordance withrecognised Standards, shall only be used forinstrument lines and open ended lines with anexternal diameter of 50 mm or less and designtemperatures not colder than –55°C.

.3 Screwed couplings complying with recognisedStandards shall only be used for accessory linesand instrumentation lines with external diametersof 25 mm or less.

5.8.3 Flanged connections

5.8.3.1 Flanges in flange connections shall be of thewelded neck, slip-on or socket welded type.

5.8.3.2 Flanges shall comply with recognised Standards fortheir type, manufacture and test. For all piping except openended, the following restrictions apply:

.1 For design temperatures colder than –55°C, onlywelded neck flanges shall be used.

.2 For design temperatures colder than –10°C, slip-on flanges shall not be used in nominal sizesabove 100 mm and socket welded flanges shallnot be used in nominal sizes above 50 mm.

5.8.4 Expansion joints Where bellows and expansion joints are provided in accor-dance with 5.7.1, the following requirements apply:

.1 If necessary, bellows should be protected againsticing.

.2 Slip joints shall not be used except within thecargo tanks.

5.8.5 Other connections Piping connections shall be joined in accordance with 5.8.2 to5.8.4, but for other exceptional cases the Administration mayconsider alternative arrangements.

5.9 Welding, post-weld heat treatment and non-destructive testing

5.9.1 GeneralWelding shall be carried out in accordance with Chapter 6.



LLOYD’S REGISTER4


5.9.2 Post-weld heat treatment Post-weld heat treatment shall be required for all butt welds ofpipes made with carbon, carbon manganese and low alloysteels. LR may waive the requirements for thermal stressrelieving of pipes with wall thickness less than 10 mm in relation to the design temperature and pressure of the pipingsystem concerned.

5.9.3 Non-destructive testingIn addition to normal controls before and during the welding,and to the visual inspection of the finished welds, as necessary for proving that the welding has been carried outcorrectly and according to the requirements of this paragraph,the following tests shall be required:

.1 100 per cent radiographic or ultrasonic inspec-tion of butt-welded joints for piping systems withdesign temperatures colder than –10°C, or withinside diameters of more than 75 mm, or wallthicknesses greater than 10 mm;

.2 When such butt-welded joints of piping sectionsare made by automatic welding proceduresapproved by LR, then a progressive reduction inthe extent of radiographic or ultrasonic inspec-tion can be agreed, but in no case to less than10 per cent of each joint. If defects are revealedthe extent of examination shall be increased to100 per cent and shall include inspection ofpreviously accepted welds. This approval canonly be granted if well-documented quality assurance procedures and records are availableto assess the ability of the manufacturer toproduce satisfactory welds consistently; and

.3 For other butt-welded joints of pipes not coveredby 5.9.3.1 and 5.9.3.2, spot radiographic orultrasonic inspection or other non-destructivetests shall be carried out depending uponservice, position and materials. In general, atleast 10 per cent of butt-welded joints of pipesshall be subjected to radiographic or ultrasonicinspection.

5.10 Installation requirements for cargo pipingoutside the cargo area

5.10.1 Bow and stern loading arrangementsThe following provisions apply to cargo piping and relatedpiping equipment located outside the cargo area:

.1 Cargo piping and related piping equipmentoutside the cargo area shall have only weldedconnections. The piping outside the cargo areashall run on the weather decks and shall be atleast 0,8 m inboard, except for cargo transferconnection piping. Such piping shall be clearlyidentified and fitted with a shutoff valve at itsconnection to the cargo piping system within thecargo area. At this location it shall also be capable of being separated, by means of aremovable spool piece and blank flanges, whennot in use.

.2 The piping is to be full penetration butt-weldedand subjected to full radiographic or ultrasonicinspection, regardless of pipe diameter anddesign temperature. Flange connections in thepiping shall only be permitted within the cargoarea and at the cargo transfer connections.

5.10.2 Turret compartment transfer systemsThe following provisions apply to liquid and vapour cargopiping where it is run outside the cargo area:

.1 Cargo piping and related piping equipmentoutside the cargo area shall have only weldedconnections.

.2 The piping shall be full penetration butt-welded,and subjected to full radiographic or ultrasonicinspection, regardless of pipe diameter anddesign temperature. Flange connections in thepiping shall only be permitted within the cargoarea and at connections to cargo hoses and theturret connection.

5.10.3 Gas fuel pipingGas fuel piping, as far as practicable, shall have welded joints.Those parts of the gas fuel piping that are not enclosed in aventilated pipe or duct according to 16.4.3, and are on theweather decks outside the cargo area, shall have full penetration butt-welded joints and shall be subjected to fullradiographic or ultrasonic inspection.

5.11 Piping system component requirements

5.11.1 Piping scantlingsPiping systems shall be designed in accordance with recognisedStandards.

5.11.2 The following criteria shall be used for determiningpipe wall thickness.The wall thickness of pipes shall not be less than:

T = (mm)

whereto = theoretical thickness

to = (mm)

withP = design pressure (MPa) referred to in 5.4 D = outside diameter (mm)K = allowable stress (N/mm2) referred to in 5.11.3e = efficiency factor equal to 1,0 for seamless pipes

and for longitudinally or spirally welded pipes, delivered by approved manufacturers of weldedpipes, that are considered equivalent to seamlesspipes when non destructive testing on welds iscarried out in accordance with RecognisedStandards. In other cases an efficiency factor ofless than 1,0, in accordance with recognisedStandards, may be required depending on themanufacturing process

to + b + c

1 – a100

P D2K e + P





b = allowance for bending (mm). The value of b shouldbe chosen so that the calculated stress in thebend, due to internal pressure only, does notexceed the allowable stress. Where such justifica-tion is not given, b should be:

b = (mm)

withr = mean radius of the bend (mm)c = corrosion allowance (mm). If corrosion or erosion is

expected the wall thickness of the piping shall beincreased over that required by other designrequirements. This allowance shall be consistentwith the expected life of the piping

a = negative manufacturing tolerance for thickness (percent).

5.11.3 Allowable stress

5.11.3.1 For pipes, the allowable stress to be considered inthe formula for t in 5.11.2 is the lower of the following values:

Rm/A or Re/B

whereRm = specified minimum tensile strength at room temper-

ature (N/mm2)Re = specified minimum yield stress at room tempera-

ture (N/mm2). If the stress strain curve does notshow a defined yield stress, the 0,2 per cent proofstress applies.

The values of A and B shall have values of at least A = 2,7and B = 1,8.

5.11.3.2 The minimum wall thickness shall be in accordancewith recognised Standards.

5.11.3.3 Where necessary for mechanical strength toprevent damage, collapse, excessive sag or buckling of pipesdue to superimposed loads, the wall thickness shall beincreased over that required by 5.11.2 or, if this is impracticable or would cause excessive local stresses, theseloads shall be reduced, protected against or eliminated byother design methods. Such superimposed loads may be dueto; supporting structures, deflections of the ship unit, liquidpressure surge during transfer operations, the weight ofsuspended valves, reaction to loading arm connections, orotherwise.

5.11.4 High pressure gas fuel outer pipes or ductingscantlingsIn fuel gas piping systems of design pressure greater than thecritical pressure, the tangential membrane stress of a straightsection of pipe or ducting shall not exceed the tensile strengthdivided by 1,5 (i.e., Rm/1,5) when subjected to the designpressure specified in 5.4. The pressure ratings of all otherpiping components shall reflect the same level of strength asstraight pipes.

D t02,5r

5.11.5 Stress analysisWhen the design temperature is –110°C or colder, a completestress analysis, taking into account all the stresses due toweight of pipes, including acceleration loads if significant,internal pressure, thermal contraction and loads induced byhogging and sagging of the ship unit for each branch of thepiping system shall be submitted to LR. For temperaturesabove –110°C, a stress analysis may be required by LR inrelation to such matters as the design or stiffness of the pipingsystem and the choice of materials. In any case, considera-tion should be given to thermal stresses even thoughcalculations are not submitted. The analysis may be carriedout according to a Code of Practice acceptable to LR.

5.11.6 Flanges, valves and fittings

5.11.6.1 Flanges, valves and other fittings shall comply withrecognised Standards, taking into account the materialselected and the design pressure defined in 5.4. For bellowsexpansion joints used in vapour service, a lower minimumdesign pressure may be accepted.

5.11.6.2 For flanges not complying with a recognisedStandard, the dimensions of flanges and related bolts shall beto the satisfaction of LR.

5.11.6.3 All emergency shutdown valves shall be of the ‘fireclosed’ type. (See 5.13.1.1 and 18.10.2).

5.11.6.4 The design and installation of expansion bellowsshall be in accordance with recognised Standards and befitted with means to prevent damage due to over-extensionor compression.

5.11.7 Ship unit cargo hoses

5.11.7.1 Liquid and vapour hoses used for cargo transfershall be compatible with the cargo and suitable for the cargotemperature.

5.11.7.2 Hoses subject to tank pressure, or the dischargepressure of pumps or vapour compressors, shall be designedfor a bursting pressure not less than five times the maximumpressure the hose will be subjected to during cargo transfer.

5.11.7.3 Each new type of cargo hose, complete with endfittings, shall be prototype-tested at a normal ambient temperature, with 200 pressure cycles from zero to at leasttwice the specified maximum working pressure. After thiscycle pressure test has been carried out, the prototype testshall demonstrate a bursting pressure of at least 5 times its specified maximum working pressure at the upper and lowerextreme service temperature. Hoses used for prototype testing shall not be used for cargo service. Thereafter, beforebeing placed in service, each new length of cargo hoseproduced shall be hydrostatically tested at ambient tempera-ture to a pressure not less than 1,5 times its specifiedmaximum working pressure, but not more than two fifths ofits bursting pressure. The hose shall be stencilled or otherwisemarked with the date of testing, its specified maximum working pressure and, if used in services other than ambienttemperature services, its maximum and minimum servicetemperature, as applicable. The specified maximum workingpressure shall not be less than 1 MPa.



LLOYD’S REGISTER6


5.12 Materials

5.12.1 The choice and testing of materials used in pipingsystems shall comply with the requirements of Chapter 6,taking into account the minimum design temperature.However, some relaxation may be permitted in the quality ofmaterial of open ended vent piping providing the temperatureof the cargo at the pressure relief valve setting is not colderthan –55°C and provided no liquid discharge to the ventpiping can occur. Similar relaxations may be permitted underthe same temperature conditions to open ended piping insidecargo tanks, excluding discharge piping and all piping insidemembrane and semi membrane tanks.

5.12.2 Materials having a melting point below 925°C shallnot be used for piping outside the cargo tanks except forshort lengths of pipes attached to the cargo tanks, in whichcase fire-resisting insulation shall be provided.

5.12.3 Cargo piping insulation system

5.12.3.1 Cargo piping systems shall be provided with a thermal insulation system as required to minimise heat leakinto the cargo during transfer operations and to protectpersonnel from direct contact with cold surfaces.

5.12.3.2 Where applicable, due to location or environmentalconditions, insulation materials should have suitable propertiesof resistance to fire and flame spread and should beadequately protected against penetration of water vapour andmechanical damage.

5.12.4 Where the cargo piping system is of a materialsusceptible to stress corrosion cracking in the presence of asalt laden atmosphere, adequate measures to avoid thisoccurring should be taken by considering material selection,protection of exposure to salty water and/or readiness forinspection.

5.13 Testing requirements

5.13.1 Type testing of piping components

5.13.1.1 ValvesReference is made to the SIGTTO publication The Selectionand Testing of Valves for LNG Applications.Each type of piping component shall be subject to the following type tests:Each type of piping component intended to be used at aworking temperature below –55°C shall be subject to thefollowing type tests:

.1 Each size and type of valve shall be subjected toseat tightness testing over the full range of operating pressures for bi-directional flow andtemperatures, at intervals, up to the rated designpressure of the valve. Allowable leakage ratesshall be to the requirements of LR. During thetesting satisfactory operation of the valve shall beverified.

.2 The flow or capacity shall be certified to a recog-nised Standard for each size and type of valve.

.3 Pressurised components shall be pressure testedto at least 1,5 times the rated pressure.

.4 For emergency shutdown valves, with materialshaving melting temperatures lower than 925°C,the type testing shall include a fire test to a standard acceptable to the Administration.Reference is made to API Std 607 Fire Test forSoft Seated Quarter Turn Valves.

5.13.1.2 Expansion bellows The following type tests shall be performed on each type ofexpansion bellows intended for use on cargo piping outsidethe cargo tank and where required by the RecognisedOrganisation, on those installed within the cargo tanks:

.1 Elements of the bellows, not pre-compressed,shall be pressure tested at not less than fivetimes the design pressure without bursting. Theduration of the test shall not be less than fiveminutes.

.2 A pressure test shall be performed on a typeexpansion joint, complete with all the accessoriessuch as flanges, stays and articulations, at theminimum design temperature and twice thedesign pressure at the extreme displacementconditions recommended by the manufacturerwithout permanent deformation.

.3 A cyclic test (thermal movements) shall beperformed on a complete expansion joint, whichshall withstand at least as many cycles under theconditions of pressure, temperature, axial move-ment, rotational movement and transversemovement as it will encounter in actual service.Testing at ambient temperature is permittedwhen this testing is at least as severe as testingat the service temperature.

.4 A cyclic fatigue test (deformation of the ship unit)shall be performed on a complete expansionjoint, without internal pressure, by simulating thebellows movement corresponding to a compen-sated pipe length, for at least 2 000 000 cyclesat a frequency not higher than 5 Hz. This test isonly required when, due to the piping arrangement, deformation loads from the shipunit are actually experienced.

5.13.2 System testing requirements

5.13.2.1 The requirements of this Section apply to pipinginside and outside the cargo tanks.

5.13.2.2 After assembly, all cargo and process piping shallbe subjected to a strength test with a suitable fluid. The testpressure is to at least 1,5 times the design pressure (1,25 timesthe design pressure where the test fluid is compressible) forliquid lines and 1,5 times the maximum system working pressure (1,25 times the maximum system working pressurewhere the test fluid is compressible) for vapour lines. Whenpiping systems or parts of systems are completely manufac-tured and equipped with all fittings, the test may beconducted prior to installation onboard the ship unit. Jointswelded onboard shall be tested to at least 1,5 times thedesign pressure.





5.13.2.3 After assembly onboard, each cargo and processpiping system shall be subjected to a leak test using air, orother suitable medium to a pressure depending on the leakdetection method applied.

5.13.2.4 In double wall gas fuel piping systems the outerpipe or duct shall also be pressure tested to show that it canwithstand the expected maximum pressure at gas piperupture.

5.13.2.5 All piping systems, including valves, fittings andassociated equipment for handling cargo or vapours, shall betested under normal operating conditions not later than at thefirst loading operation, in accordance with recognisedStandards.



LLOYD’S REGISTER8

Materials of Construction and Quality Control

Section

6.1 Definitions

6.2 Scope and general requirement

6.3 General test requirements and specifications

6.4 Requirements for metallic materials

6.5 Welding of metallic materials and non-destructive testing

LR 6.6 Specific welding requirements for liquefiedpetroleum gas and liquefied natural gas systems

6.7 Non-metallic materials

6.1 Definitions

6.1.1 Where reference is made in this Chapter to GradesA, B, D, E, AH, DH, EH and FH hull structural steels, thesesteel grades are hull structural steels according to the Rulesfor the Manufacture, Testing and Certification of Materials(hereinafter referred to as the Rules for Materials).

6.1.2 A piece is the rolled product from a single slab orbillet or from a single ingot if this is rolled directly into plates,strip, sections or bars.

6.1.3 A batch is the number of items or pieces to beaccepted or rejected together, on the basis of the tests to becarried out on a sampling basis. The size of a batch is givenin the recognised Standards.

6.1.4 Accelerated Cooling (AcC) is a process that aimsto improve mechanical properties by controlled cooling withrates higher than air cooling, immediately after the final TMCPoperation. Direct quenching is excluded from acceleratedcooling. The material properties conferred by TMCP and AcCcannot be reproduced by subsequent normalising or otherheat treatment.

6.1.5 Controlled Rolling (CR), also known as Norma lisingRolling (NR), is a rolling procedure in which the final deformation is carried out in the normalising temperaturerange, resulting in a material condition generally equivalent tothat obtained by normalising.

LR 6.1.1 Normalising (N) refers to an additional heatingcycle of rolled steel above the critical temperature, Ac3, and inthe lower end of the austenite recrystallisation region followedby air cooling. The process improves the mechanical propertiesof as-rolled steel by refining the grain size.

LR 6.1.2 Quenching and Tempering (QT) is a heattreatment process in which steel is heated to an appropriatetemperature above the Ac3 and then cooled with an appropriatecoolant for the purpose of hardening the microstructure,followed by tempering, a process in which the steel is re-heatedto an appropriate temperature, not higher than the Ac1 to restorethe toughness properties by improving the microstructure.

6.1.6 Thermo-Mechanical Controlled Processing(TMCP) is a procedure that involves strict control of both thesteel temperature and the rolling reduction. Unlike CR, theproperties conferred by TMCP cannot be reproduced bysubsequent normalising or other heat treatment. The use ofaccelerated cooling on completion of TMCP may also beaccepted subject to approval by the Administration. The sameapplies for the use of tempering after completion of the TMCP.

6.2 Scope and general requirement

6.2.1 This Chapter gives the requirements for metallicand non-metallic materials used in the construction of thecargo system. This includes requirements for joiningprocesses, production process, personnel qualification, NDTand inspection and testing including production testing. Therequirements for rolled materials, forgings and castings aregiven in 6.4 and Tables 6.1, 6.2, 6.3, 6.4 and 6.5. The require-ments for weldments are given in 6.5 and the guidance fornon metallic materials is given in Appendix 1. A quality assurance/quality control (QA/QC) program shall be implemented to ensure the requirements of 6.2.1 arecomplied with.

6.2.2 The manufacture, testing, inspection and docu-mentation shall be in accordance with the requirements of thisChapter and the Rules for Materials. Testing and inspectionto other recognised Standards will be subject to specialagreement.

6.2.3 Where post-weld heat treatment is specified orrequired, the properties of the base materials, weld and heataffected zone shall be determined in the heat treated condi-tion, in accordance with the requirements specified in thisChapter. Alternative arrangements for Charpy V-notch impacttest temperature following post-weld heat treatment will besubject to special consideration.

6.3 General test requirements and specifications

LR 6.3.1 All mechanical tests required by this Chaptershall be carried out in accordance with the Rules for Materials.

LR 6.3.2 Acceptance tests for metallic materials shallinclude Charpy V-notch impact tests unless specifiedotherwise; the largest specimen possible for the materialthickness should be machined. Requirements for testingspecimens smaller than 5,0 mm in size shall be in accordancewith recognised Standards.

LR 6.3.3 The bend test may be omitted as a materialacceptance test, but is required for weld tests.







LR 6.4.1 The material grades for the construction of thehull structure are to comply with the requirements of Table 2.4.1 in Pt 4, Ch 2 unless the minimum metaltemperature is the result of heat conduction from the cargo, inwhich case hull materials shall be in accordance with Table 6.5.

LR 6.4.2 The sheerstrake is to be of Grade E/EH steelfor ship units storing and offloading liquefied gases in bulk.

6.4 Requirements for metallic materials

6.4.1 General requirements for metallic materials

6.4.1.1 The requirements for materials of construction areshown in the Tables as follows:Table 6.1: Plates, pipes (seamless and welded), sections

and forgings for cargo tanks and process pressure vessels for design temperatures not lower than 0°C.

Table 6.2: Plates, sections and forgings for cargo tanks, secondary barriers and process pressure vessels for design temperatures below 0°C and down to –55°C.

Table 6.3: Plates, sections and forgings for cargo tanks, secondary barriers and process pressure vessels for design temperatures below –55°C and down to –165°C.

Table 6.4: Pipes (seamless and welded), forgings and castings for cargo and process piping for design temperatures below 0°C and down to –165°C.

Table 6.5: Plates and sections for hull structures required by 4.19.1.2 and 4.19.1.3.


Table 6.1 Plates, pipes (seamless and welded, see Notes 1 and 2), sections and forgings for cargo tanks andprocess pressure vessels for design temperatures not lower than 0°C

Chemical composition and heat treatment

• Carbon-manganese steel• Fully killed fine grain steel• Small additions of alloying elements by agreement with LR• Composition limits to be approved by LR• Normalised, quenched and tempered, see Note 4

Tensile and toughness (impact) test requirements

Sampling frequency

• Plates Each ‘piece’ to be tested

• Sections and forgings Each ‘batch’ to be tested

Mechanical properties

• Tensile properties Specified minimum yield stress not to exceed 410 N/mm2, see Note 5

Toughness (Charpy V-notch test)

• Plates Transverse test pieces. Minimum average value (KV) 27J

• Sections and forgings Longitudinal test pieces. Minimum average energy (KV) 41J

• Test temperature Thickness t (mm) Test temperature (°C)• t ≤ 20 0

20 < t ≤ 40, see Note 3 –20

NOTES1. For seamless pipes and fittings, normal practice applies. The use of longitudinally and spirally welded pipes shall be specially approved

by LR.2. Charpy V-notch impact tests are not required for pipes where the thickness is less than 15 mm.3. This Table is generally applicable for material thicknesses up to 40 mm. Proposals for greater thicknesses shall be approved by LR.4. A controlled rolling (normalising rolling) procedure may be used as an alternative. In addition, TCMP steel may be used as an alternative

in applications where post-weld heat treatment is not required.5. Materials with specified minimum yield stress exceeding 410 N/mm2 may be approved by LR. For these materials, particular attention

shall be given to the hardness of the welded and heat affected zones.

3LLOYD’S REGISTER




Table 6.2 Plates, sections and forgings (see Note 1) for cargo tanks, secondary barriers and process pressure vessels for design temperatures below 0°C and down to –55°C, maximum thickness 25 mm (see Note 2)

Chemical composition and heat treatment

• Carbon-manganese steel• Fully killed, aluminium treated fine grain steel• Chemical composition (ladle analysis)

Optional additions: Alloys and grain refining elements may be generally in accordance with the following:

Al content total 0,020% min. (acid soluble 0,015% min.)• Normalised, or quenched and tempered, see Note 4


Sampling frequency



Mechanical properties

• Tensile properties Specified minimum yield stress not to exceed 410 N/mm2, see Note 5


• Plates Transverse test pieces. Minimum average energy value (KV) 27J


• Test temperature 5°C below the design temperature or –20°C, whichever is lower

NOTES1. The Charpy V-notch and chemistry requirements for forgings may be specially considered by LR.2. For material thickness of more than 25 mm, Charpy V-notch tests shall be conducted as follows:

Material thickness (mm) Test temperature (°C)25 < t ≤ 30 10°C below design temperature or –20°C, whichever is lower30 < t ≤ 35 15°C below design temperature or –20°C, whichever is lower35 < t ≤ 40 20°C below design temperature

40 < t Temperature approved by LRThe impact energy value shall be in accordance with the Table for the applicable type of test specimen.Materials for tanks and parts of tanks which are completely thermally stress relieved after welding may be tested at a temperature 5°Cbelow design temperature or –20°C, whichever is lower.For thermally stress relieved reinforcements and other fittings, the test temperature shall be the same as that required for the adjacenttank shell thickness.

3. By special agreement with LR, the carbon content may be increased to 0,18% maximum provided the design temperature is not lowerthan –40°C.

4. A controlled rolling (normalising rolling) procedure may be used as an alternative. In addition, TMCP steel may be used as an alternativein applications where post-weld heat treatment is not required.

5. Materials with specified minimum yield stress exceeding 410 N/mm2 may be approved by LR. For these materials, particular attentionshall be given to the hardness of the welded and heat affected zones.

GuidanceFor materials exceeding 25 mm in thickness for which the test temperature is –60°C or lower, the application of specially treated steels orsteels in accordance with Table 6.3 may be necessary.

Ni Cr Mo Cu Nb V0,80% max. 0,25% max. 0,08% max. 0,35% max. 0,05% max. 0,10% max.

C Mn Si S P0,16% max. 0,70-1,60% 0,10-0,50% 0,025% max. 0,025% max.see Note 3





Table 6.3 Plates, sections and forgings (see Note 1) for cargo tanks, secondary barriers and process pressure vessels for design temperatures below –55°C and down to –165°C (see Note 2), maximum thickness 25 mm (see Notes 3 and 4)

Minimum design Chemical composition, see Note 5, and heat treatment

Impact test temperature temperature (°C)

–60 1,5% nickel steel – normalised or normalised and tempered or quenched and tempered or TMCP, –65see Note 6

–65 2,25% nickel steel – normalised or normalised and tempered or quenched and tempered or TMCP, –70see Notes 6 and 7

–90 3,5% nickel steel – normalised or normalised and tempered or quenched and tempered or TMCP, –95see Notes 6 and 7

–105 5% nickel steel – normalised or normalised and tempered or quenched and tempered, –110see Notes 6, 7 and 8

–165 9% nickel steel – double normalised and tempered or quenched and tempered, see Note 6 –196

–165 Austenitic steels, such as types 304, 304L, 316, 316L, 321 and 347 solution treated, see Note 9 –196

–165 Aluminium alloys; such as type 5083 annealed Not required

–165 Austenitic Fe-Ni alloy (36% nickel) heat treatment as agreed Not required


Sampling frequency




• Plates Transverse test pieces. Minimum average energy value (KV) 27J


NOTES1. The impact test required for forgings used in critical applications shall be subject to special consideration by LR.2. The requirements for design temperatures below –165°C shall be specially agreed with LR.3. For materials 1,5% Ni, 2,25% Ni, 3,5% Ni and 5% Ni, with thicknesses greater than 25 mm, the impact tests shall be conducted as

follows:Material thickness (mm) Test temperature (°C)

25 < t ≤ 30 10°C below design temperature30 < t ≤ 35 15°C below design temperature35 < t ≤ 40 20°C below design temperature

The energy value shall be in accordance with the Table for the applicable type of test specimen. For material thickness of more than40 mm, the Charpy V-notch values shall be specially considered.

4. For 9% Ni steels, austenitic stainless steels and aluminium alloys, thickness greater than 25 mm may be used.5. The chemical composition limits shall be in accordance with Ch 3,6 of the Rules for Materials.6. TMCP nickel steels will be subject to acceptance by LR.7. A lower minimum design temperature for quenched and tempered steels may be specially agreed with LR.8. A specially heat treated 5% nickel steel, for example, triple heat treated 5% nickel steel, may be used down to –165°C, provided that

the impact tests are carried out at –196°C.9. The impact test may be omitted subject to agreement with LR.

5LLOYD’S REGISTER




Table 6.4 Pipes (seamless and welded, see Note 1), forgings and castings (see Note 2) for cargo and process piping for design temperatures below 0°C and down to –165°C (see Note 3), maximumthickness 25 mm

Impact test Minimum design

Chemical composition, see Note 5, and heat treatmenttemperature Test temp. (°C) Minimum averageenergy (KV)

–55 Carbon-manganese steel. Fully killed fine grain. Normalised or as agreed, See Note 4 27see Note 6

–65 2.25% nickel steel. Normalised, normalised and tempered or quenched and –70 34tempered, see Note 6

–90 3.5% nickel steel. Normalised, normalised and tempered or quenched and –95 34tempered, see Note 6

–165 9% nickel steel, see Note 7. Double normalised and tempered or quenched –196 41and tempered

–165 Austenitic steels, such as types 304. 304L, 316, 316L, 321 and 347. Solution –196 41treated, see Note 8

–165 Aluminium alloys, such as type 5083 annealed Not required


Sampling frequency

• Each ‘batch’ to be tested.


• Impact test: longitudinal test pieces

NOTES1. The use of longitudinally or spirally welded pipes shall be specially approved by LR.2. The requirements for forgings and castings may be subject to special consideration by LR.3. The requirements for design temperatures below –165°C shall be specially agreed with LR.4. The test temperature shall be 5°C below the design temperature or –20°C whichever is lower.5. The composition limits shall be in accordance with Ch 6,4 of the Rules for Materials.6. A lower design temperature may be specially agreed with LR for quenched and tempered materials.7. This chemical composition is not suitable for castings.8. Impact tests may be omitted subject to agreement with LR.

Table 6.5 Plates and sections for hull structures required by 4.19.1.2 and 4.19.1.3

Minimum design Maximum thickness (mm) for steel gradestemperature of hull

structure (°C) A B D E AH DH EH FH

0 and above, see Note 1–5 and above, see Note 2 To comply with Pt 10, Ch 1,3

down to –5 15 25 30 50 25 45 50 50

down to –10 x 20 25 50 20 40 50 50

down to –20 x x 20 50 x 30 50 50

down to –30 x x x 40 x 20 40 50

Below –30In accordance with Table 6.2, except that the thickness limitation given in Table 6.2 and in Note 2 of that Table does not apply

NOTES‘x’ means steel grade not to be used.1. For the purpose of 4.19.1.3.2. For the purpose of 4.19.1.2.


6.5 Welding of metallic materials and non-destructive testing

6.5.1 General

6.5.1.1 This Section shall apply to primary and secondarybarriers only, including the inner hull where this forms thesecondary barrier. Acceptance testing is specified for carbon,carbon-manganese, nickel alloy and stainless steels, butthese tests may be adapted for other materials. At the discretion of LR, impact testing of stainless steel andaluminium alloy weldments may be omitted and other testsmay be specially required for any material.

6.5.2 Welding consumables

6.5.2.1 Consumables for welding of cargo tanks shall be inaccordance with Chapter 11 of the Rules for Materials andrecognised Standards.

6.5.3 Welding procedure tests for cargo tanks andprocess pressure vessels

6.5.3.1 Welding procedure tests for cargo tanks,secondary barriers, process pressure vessels and pressurepipework are to be qualified in accordance with Chapter 12 ofthe Rules for Materials.

LR 6.6 Specific welding requirements for liquefiedpetroleum gas and liquefied natural gassystems

LR 6.6.1 Scope

LR 6.6.1.1 The requirements of this Section apply towelding of cargo tanks, storage tanks, containment systems,process pressure vessels and pressure piping for liquefiednatural gas systems.

LR 6.6.1.2 The requirements of this Section include thewelding of carbon, carbon-manganese, nickel alloy, austeniticstainless steels and aluminium alloys specified in the Rules forMaterials, as suitable for use in low temperature service.

LR 6.6.1.3 The requirements of this Section are inaddition to those requirements specified in Chapter 13,Sections 1, 4 and 5 of the Rules for Materials.

LR 6.6.2 Welding qualificationsAll welding procedures used during construction are to bequalified in accordance with the requirements specified inChapter 12 of the Rules for Materials for liquid gasapplications.

LR 6.6.3 Production weld test frequency

LR 6.6.3.1 For cargo tanks and process pressurevessels, except integral and membrane tanks, productionweld tests shall be performed for each 50 m of butt weld jointand should be representative of each welding procedure andposition used in construction.

LR 6.6.3.2 Production tests are required for secondarybarriers but the number of tests required may be reduced to1 in every 100 m of butt weld.

LR 6.6.3.3 Requirements for production testing of integraland membrane tanks are to be agreed with LR prior tomanufacture.

LR 6.6.4 Production weld testing requirements

LR 6.6.4.1 The type and number of specimens to beremoved from each test plate for mechanical testing shall beas specified for the original welding procedure qualificationtest, except that:(a) the all weld tensile test may be omitted; and(b) the number of impact tests from the heat affected zone

may be reduced to sampling the location that demon-strated the lowest impact energy during procedurequalification.

LR 6.6.4.2 For independent tanks, Types A and B, thetransverse tensile tests may also be omitted.

LR 6.6.4.3 The results of the mechanical tests are to meetthe minimum requirements specified for the original weldingprocedure qualification test as specified in Chapter 12 of theRules for Materials.

LR 6.6.4.4 Should any impact test fail to meet require-ments, consideration will be given to acceptance based onsatisfactory results from two drop weight tests from the failedlocation. The test temperature for these shall be no higher thatthat specified for the impact tests and the acceptance criteriafor both tests shall be no break.

LR 6.6.5 Non-destructive examination

LR 6.6.5.1 All welds are to be subject to non-destructiveexamination in accordance with requirements specified inChapter 13, Sections 4 and 5 of the Rules for Materials unlessmore stringent requirements are specified below.

LR 6.6.5.2 Radiographic examination may be substitutedby ultrasonic examination, see Ch 13,4.15 of the Rules forMaterials. In addition, ultrasonic examination may be used toaugment radiographic testing for complex or critical welds.

LR 6.6.5.3 Type A independent and semi-membranetanks:(a) where the minimum design temperature is less than or

equal to –20°C, the extent and type of testing shall beas for Type B tanks in LR 6.6.5.4.

(b) where the minimum design temperature is greater than–20°C, the extent and type of testing shall include 100 per cent volumetric examination of butt weld intersections, plus 10 per cent of other butt welds.

(c) the remaining tank structure shall be subject to crackdetection examination in accordance with recognisedstandards and the extent of examination is to be agreedwith LR.



LLOYD’S REGISTER6


LR 6.6.5.4 Type B independent tanks:Irrespective of design temperature, all full penetration buttwelds will be subject to 100 per cent volumetric examination.Other welds shall be subject to crack detection examination inaccordance with recognised Standards and the extent ofexamination is to be agreed with LR.

LR 6.6.5.5 Type C independent tanks and process pressure vessels:The extent of examination is dependent on the designconditions. Where the design incorporates a joint factorgreater than 0,85, all butt welds will be subject to 100 percent volumetric examination plus 10 per cent surface crackdetection. Where the weld joint factor is less than or equal to0,85, partial inspection may be considered. However, thisshould not be less than 10 per cent volumetric examinationof full penetration butt welds, and 100 per cent surface crackdetection of nozzle reinforcing rings and other vesselopenings.

LR 6.6.5.6 Integral and membrane tanks:Inspection is to be in accordance with recognised Standardsand the extent and type of inspection is to be agreed with LR.

LR 6.6.5.7 Secondary barrier:Where the outer shell of the hull is part of the secondarybarrier, all sheerstrake butt welds and the intersections of allbutt and seam welds in the side shell shall be examinedvolumetrically. The extent of inspections is to be agreed withLR.

LR 6.6.5.8 Inner hull and independent tank structuressupporting internal insulation tanks:Inspection requirements are to be in accordance withrecognised Standards and are to be agreed with LR.

LR 6.6.5.9 Piping:(a) for piping systems with design temperatures lower than

–10°C and with inside diameters of more than 75 mm orwall thicknesses greater than 10 mm, piping shall besubject to 100 per cent radiographic inspection of butt-welded joints;

(b) for butt-welded joints made using fully automatic weldingprocedures during pipe shop fabrication, the extent ofradiographic inspection may be progressively reducedby special agreement with LR. In no case will this bereduced below 10 per cent of joints. If defects arerevealed the extent of examination shall be increased to100 per cent and will include inspection of previouslyaccepted welds. This special approval will only begranted where the fabricator has a well-documentedquality assurance system that is working effectively andwill be subject to audit by LR;

(c) for other butt-welded joints, spot radiography or othernon-destructive tests shall be carried out depending onthe service, position and materials. In general, at least10 per cent of butt-welded joints of pipes should beradiographed. The extent of examination is to be agreedwith LR.

6.7 Non-metallic materials

6.7.1 General

The information in the attached Appendix 1 is given for guidance in the selection and use of these materials, basedon the experience to date.




Document1 12/04/02 15:23 Page 1

Cargo Pressure/Temperature Control

Section

7.1 Methods of control

7.2 Design of systems

7.3 Reliquefaction of cargo vapours

7.4 Thermal oxidation of vapours

7.5 Pressure accumulation systems

7.6 Liquid cargo cooling

7.7 Segregation

7.8 Availability

7.1 Methods of control

7.1.1 With the exception of tanks designed to withstandfull gauge vapour pressure of the cargo under conditions ofthe upper ambient design temperatures, cargo tanks’ pressure and temperature shall be maintained at all timeswithin their design range by either one, or a combination of,the following methods:

.1 reliquefaction of cargo vapours

.2 thermal oxidation of vapours

.3 pressure accumulation

.4 liquid cargo cooling.

7.1.2 Venting of the cargo to maintain cargo tank pressure and temperature is not acceptable except in emergency situations. The Administration may permit certaincargoes to be controlled by venting cargo vapours to theatmosphere at sea.

7.2 Design of systems

LR 7.2.1 Details of the proposed system of cargo pres-sure/temperature control are to be submitted forconsideration.The ambient temperatures for air and sea-water are to betaken at their highest daily mean temperatures for the unit’sproposed area of operation based on the 100 year averagereturn period. The ambient temperatures are to be roundedup to the nearest degree Celsius. The ambient temperatures are not to be taken as less than45°C for air and 32°C for sea-water unless agreed by LR.The overall capacity of the system shall be such that it cancontrol the pressure within the design conditions withoutventing to atmosphere.

LR 7.2.2 The system is to be tested at entry into serviceto prove its capability to maintain the class notationtemperature and pressure.

7.3 Reliquefaction of cargo vapours

7.3.1 GeneralThe reliquefaction system may be arranged in one of thefollowing ways:

.1 A direct system where evaporated cargo iscompressed, condensed and returned to thecargo tanks.

.2 An indirect system where cargo or evaporatedcargo is cooled or condensed by refrigerant with-out being compressed.

.3 A combined system where evaporated cargo iscompressed and condensed in a cargo/refrigerant heat exchanger and returned to thecargo tanks.

.4 If the reliquefaction system produces a wastestream containing methane during pressurecontrol operations within the design conditions,these waste gases, as far as reasonably practi-cable, are disposed of without venting toatmosphere.

7.3.2 CompatibilityRefrigerants used for reliquefaction shall be compatible withthe cargo they may come into contact with.In addition, when several refrigerants are used and may comeinto contact, they shall be compatible with each other.

7.4 Thermal oxidation of vapours

The use of thermal oxidation equipment on ship unitsengaged in the production, storage and offloading of liquefied gases in bulk at a fixed location is not anticipated, inthe event that this or similar equipment is used it is to complywith Lloyd’s Register’s Rules and Regulations for theConstruction and Classification of Ships for the Carriage ofLiquefied Gases in Bulk.

7.5 Pressure accumulation systems

The containment system insulation, design pressure or bothshall be adequate to provide for a suitable margin for theoperating time and temperatures involved. No additional pressure and temperature control system is required.

7.6 Liquid cargo cooling

The bulk cargo liquid may be refrigerated by coolant circulated through coils fitted either inside the cargo tank oronto the external surface of the cargo tank.




Cargo Pressure/Temperature Control

7.7 Segregation

Where two or more cargoes that may react chemically in adangerous manner are carried simultaneously, separatesystems as defined in 1.2, each complying with availabilitycriteria as specified in 7.8, shall be provided for each cargo.For simultaneous carriage of two or more cargoes that are notreactive to each other but where, due to properties of theirvapour, separate systems are necessary, separation may beby means of isolation valves.

7.8 Availability

The availability of the system and its supporting auxiliaryservices shall be such that:

.1 In case of a single failure of a mechanical non-static component or a component of the controlsystems, the cargo tanks’ pressure and temper-ature can be maintained within their design rangewithout affecting other essential services.

.2 Redundant piping systems are not required.

.3 Heat exchangers that are solely necessary formaintaining the pressure and temperature of thecargo tanks within their design ranges shall havea stand-by heat exchanger unless they have acapacity in excess of 25 per cent of the largestrequired capacity for pressure control and theycan be repaired onboard without externalresources. Where an additional and separatemethod of cargo tank pressure and temperaturecontrol is fitted that is not reliant on the sole heatexchanger, then a standby heat exchanger is notrequired.

.4 For any cargo heating or cooling medium, provisions shall be made to detect the leakage oftoxic or flammable vapours into an otherwisenon-hazardous area or overboard in accordancewith 13.6. Any vent outlet from this leak detec-tion arrangement shall be to a non-hazardousarea and be fitted with a flame screen.

LR 7.8.1 It is recommended that a reasonable marginin plant output over maximum load be allowed for possibleoverall inefficiencies under service conditions. It is also recom-mended that due regard be given to any additional capacityrequired to deal with cargo loading conditions.

LR 7.8.2 It is recommended that adequate spares,together with the tools necessary for maintenance, or repair,be carried. The spares are to be determined by the Owneraccording to the design and intended service. The maintenance of the spares is the responsibility of the Owner.



LLOYD’S REGISTER2

Vent Systems for Cargo Containment

Section

8.1 General

8.2 Pressure relief systems

8.3 Vacuum protection systems

8.4 Sizing of pressure relieving system

8.1 General

All cargo tanks shall be provided with a pressure relief systemappropriate to the design of the cargo containment systemand the cargo being carried. Hold space and interbarrierspaces, which may be subject to pressures beyond theirdesign capabilities, shall also be provided with a suitable pressure relief system. Pressure control systems specified inChapter 7 shall be independent of the pressure relief systems.

8.2 Pressure relief systems

8.2.1 Cargo tanks, including deck tanks, are to be fittedwith a minimum of two Pressure Relief Valves (PRVs) eachbeing of equal size within manufacturer’s tolerances and suitably designed and constructed for the prescribed service.

8.2.2 Interbarrier spaces shall be provided with pressurerelief devices. Reference is made to IACS UnifiedInterpretation GC9 Guidance for sizing pressure relief systemsfor interbarrier spaces 1988. For membrane systems, thedesigner shall demonstrate adequate sizing of interbarrierspace PRVs.

8.2.3 The setting of the PRVs shall not be higher than thevapour pressure that has been used in the design of the tank.Where two or more PRVs are fitted, valves comprising notmore than 50 per cent of the total relieving capacity may beset at a pressure up to 5 per cent above MARVS to allowsequential lifting, minimising unnecessary release of vapour.

8.2.4 The following temperature requirements apply toPRVs fitted to pressure relief systems:

.1 PRVs on cargo tanks with a design temperaturebelow 0°C shall be designed and arranged toprevent their becoming inoperative due to iceformation.

.2 The effects of ice formation due to ambienttemperatures shall be considered in theconstruction and arrangement of PRVs.

.3 PRVs shall be constructed of materials with amelting point above 925°C. Lower melting pointmaterials for internal parts and seals may beaccepted provided that fail-safe operation of thePRV is not compromised.

.4 Sensing and exhaust lines on pilot operated reliefvalves shall be of suitably robust construction toprevent damage.

8.2.5 Valve testing

PRVs shall be tested in accordance with a RecognisedStandard or equivalent national standards. Reference is madeto:ISO 21013-1 2008 – Cryogenic vessels – Pressure-reliefaccessories for cryogenic service – Part 1: Reclosable pressure-relief valves; andISO 4126-1; 2004 Safety devices for protection againstexcessive pressure – Part 1 and part 4: Safety valves.

8.2.5.1 PRVs shall be type tested. Type tests shall include:.1 verification of relieving capacity..2 cryogenic testing when operating at design

temperatures colder than –55°C..3 seat tightness testing..4 pressure containing parts are to be pressure

tested to at least 1,5 times the design pressure.

8.2.5.2 Each PRV shall be tested to ensure that:.1 it opens at the prescribed pressure setting, with

an allowance not exceeding ±10 per cent for 0 to0,15 MPa, ±6 per cent for 0,15 to 0,3 MPa, ±3 per cent for 0,3 MPa and above.

.2 seat tightness is acceptable.

.3 pressure containing parts are to withstand atleast 1,5 times the design pressure.

LR 8.2.1 As soon as practicable prior to proceeding ongas trials, pressure relief valves are to be tested and installedin accordance with the manufacturer’s recommended procedures to the Surveyor’s satisfaction. Where valves arestored prior to installation on board, the storage arrangementsare also to be in accordance with the manufacturer’s recom-mended procedures.

8.2.6 PRVs shall be set and sealed by the Administrationor recognised organisation acting on its behalf and a record ofthis action, including the valves’ set pressure, shall be retainedonboard the ship unit.

8.2.7 Cargo tanks may be permitted to have more thanone relief valve set pressure in the following cases:

.1 installing two or more properly set and sealedPRVs and providing means as necessary forisolating the valves not in use from the cargotank; or

.2 installing relief valves whose settings may bechanged by the use of a previously approveddevice not requiring pressure testing to verify thenew set pressure. All other valve adjustmentsshall be sealed.

8.2.8 Changing the set pressure under the provisions of8.2.7, and the corresponding resetting of the alarms referredto in 13.4.2, shall be carried out under the supervision of theMaster in accordance with approved procedures and asspecified in the operating manual of the ship unit. Changes inset pressure shall be recorded in the ship unit’s log and a signshall be posted in the cargo control room if provided, in themain control area if separate from the cargo control room, andat each relief valve, stating the set pressure.





8.2.9 In the event of a failure of a cargo tank PRV a safemeans of emergency isolation shall be available.

.1 Procedures are to be provided and included inthe cargo operations manual (see 18.2).

.2 The procedures shall allow only one of the cargotank’s installed PRVs to be isolated.

.3 Isolation of the PRV shall be carried out under thesupervision of the Master. This action shall berecorded in the ship unit’s log and a sign postedin the cargo control room, if provided, and at thePRV.

.4 The tank shall not be loaded until the full relieving capacity is restored.

8.2.10 Each PRV installed on a cargo tank shall beconnected to a venting system, which shall be:

.1 so constructed that the discharge will be unimpeded and directed vertically upwards at theexit.

.2 arranged to minimise the possibility of water orsnow entering the vent system.

.3 arranged such that the height of vent exits shallnot be less than B/3 or 6 m, whichever is thegreater, above the weather deck.

.4 6 m above working areas and walkways.

8.2.11 Cargo PRV vent exits shall be arranged at adistance at least equal to B or 25 m, whichever is less, fromthe nearest air intake, outlet or opening to accommodationspaces, service spaces and control stations, or other non-hazardous areas.

.1 All other vent outlets connected to the cargocontainment system shall be arranged at adistance of at least 10 m from the nearest airintake, outlet or opening to accommodationspaces, service spaces and control stations, orother non-hazardous areas.

8.2.12 All other cargo vent outlets not dealt with in otherchapters shall be arranged in accordance with 8.2.10 and8.2.11. Means shall be provided to prevent liquid overflowfrom vent mast outlets, due to hydrostatic pressure fromspaces to which they are connected.

8.2.13 If cargoes that react in a dangerous manner witheach other are carried simultaneously, a separate pressurerelief system shall be fitted for each one.

8.2.14 In the vent piping system, means for draining liquidfrom places where it may accumulate shall be provided. ThePRVs and piping shall be arranged so that liquid can, underno circumstances, accumulate in or near the PRVs.

8.2.15 Suitable protection screens of not more than 13 mm square mesh shall be fitted on vent outlets to preventthe ingress of foreign objects without adversely affecting theflow. Protective screens when storing pentane are also tocomply with 17.2.

8.2.16 All vent piping shall be designed and arranged notto be damaged by; the temperature variations to which it maybe exposed, forces due to flow or the motions of the ship unit.

8.2.17 PRVs shall be connected to the highest part of thecargo tank above deck level. PRVs shall be positioned on thecargo tank so that they will remain in the vapour phase at thefilling limit (FL) as defined in Chapter 15, under conditions of15° list and 0,015L trim, where L is defined in 1.2.

8.2.18 The adequacy of the vent system fitted on tanksloaded in accordance with 15.5.2, is to be demonstratedusing the Guidelines for the Evaluation of the Adequacy ofType C Tank Vent Systems, IMO Resolution A.829(19). A relevant certificate shall be permanently kept onboard the shipunit. For the purposes of this paragraph, vent system means:

.1 the tank outlet and the piping to the PRV.

.2 the PRV.

.3 the piping from the PRVs to the location ofdischarge to the atmosphere, including any inter-connections and piping that joins other tanks.

8.3 Vacuum protection systems

8.3.1 Cargo tanks not designed to withstand a maximumexternal pressure differential 0,025 MPa, or tanks that cannotwithstand the maximum external pressure differential that canbe attained at maximum discharge rates with no vapourreturn into the cargo tanks, or by operation of a cargo refrigeration system, or by thermal oxidation, shall be fittedwith:

.1 two independent pressure switches to sequen-tially alarm and subsequently stop all suction ofcargo liquid or vapour from the cargo tank andrefrigeration equipment, if fitted, by suitablemeans at a pressure sufficiently below the maximum external designed pressure differentialof the cargo tank; or

.2 vacuum relief valves with a gas flow capacity atleast equal to the maximum cargo discharge rateper cargo tank, set to open at a pressure sufficiently below the external design differentialpressure of the cargo tank.

8.3.2 Subject to the requirements of Chapter 17, thevacuum relief valves shall admit an inert gas, cargo vapour orair to the cargo tank and shall be arranged to minimise thepossibility of the entrance of water or snow see also LR 8.3.1. Ifcargo vapour is admitted it shall be from a source other thanthe cargo vapour lines.

LR 8.3.1 Vacuum relief valves are not to admit air to thecargo tanks except where satisfactory controls, low pressurealarms and automatic devices for stopping cargo pumps andcompressors, etc., are fitted and adjusted such that thepressure in the tanks cannot fall below a predeterminedminimum safe level. Details are to be submitted forconsideration.

8.3.3 The vacuum protection system shall be capable ofbeing tested to ensure that it operates at the prescribed pres-sure.



LLOYD’S REGISTER2

8.4 Sizing of pressure relieving system

8.4.1 Sizing of pressure relief valvesPRVs shall have a combined relieving capacity for each cargotank to discharge the greater of the following, with not morethan a 20 per cent rise in cargo tank pressure above theMARVS:

.1 the maximum capacity of the cargo tank inertingsystem if the maximum attainable working pressure of the cargo tank inerting systemexceeds the MARVS of the cargo tanks; or

.2 vapours generated under fire exposurecomputed using the following formula:

Q = FGA0,82 (m3/s)

whereQ = minimum required rate of discharge of air at

standard conditions of 273,15 Kelvin (K) and0,1013 MPa

F = fire exposure factor for different cargo typesF = 1,0 for tanks without insulation located on deckF = 0,5 for tanks above the deck when insulation is

approved by LR. (Approval will be based on the useof a fireproofing material, the thermal conductanceof insulation, and its stability under fire exposure)

F = 0,5 for uninsulated independent tanks installed inholds

F = 0,2 for insulated independent tanks in holds (oruninsulated independent tanks in insulated holds)

F = 0,1 for insulated independent tanks in inerted holds(or uninsulated independent tanks in inerted, insu-lated holds)

F = 0,1 for membrane and semi membrane tanksFor independent tanks partly protruding throughthe weather decks, the fire exposure factor shall bedetermined on the basis of the surface areas aboveand below deck

G = gas factor

G =

withT = temperature in Kelvin at relieving conditions, i.e.

120 per cent of the pressure at which the pressurerelief valve is set

L = latent heat of the material being vaporised at relieving conditions, in kJ/kg

D = a constant based on relation of specific heats k andis calculated as follows

D = k

k = ratio of specific heats at relieving conditions, andthe value of which is between 1,0 and 2,2. If k isnot known, D = 0,606 shall be used.

Z = compressibility factor of the gas at relieving condi-tions; if not known, Z = 1,0 shall be used.

M = molecular mass of the product.The gas factor of each cargo to be carried shall be deter-mined and the highest value shall be used for PRV sizing.

A = external surface area of the tank (m2) for differenttank types, as shown in Fig. 8.1:

2(k + 1)k + 1k – 1

12,4LD

ZTM

8.4.1.3 The required mass flow of air at relieving conditionsis given by:

Mair = Q ρair (kg/s)

where:

Density of air (ρair) = 1,293 kg/m3 (air at 273,15 K, 0,1013MPa)

Vent Systems for Cargo ContainmentRULES AND REGULATIONS FOR THE CLASSIFICATION OF A FLOATING OFFSHORE INSTALLATION AT A FIXED LOCATION, June 2013



Cylindrical tanks with spherically dished,hemispherical or semi-ellipsoidal heads

or spherical tanks

≤Lmin/10L excluded

Prismatic tanks

Bilobe tanks

Excluded

D

≤D/10

Excluded

Horizontal cylindrical tanks arrangement

≤D/10Excluded

≤D/10

D

Fig. 8.1


8.4.2 Sizing of vent pipe system

As in 5.2.1.4 and 5.6.4 the relief system is to be designed inaccordance with API 521 Guide for Pressure-relieving andDepressuring Systems: Petroleum petrochemical and naturalgas industries – Pressure-relieving and depressuring systems,taking into account the following.

8.4.2.1 Pressure losses upstream and downstream of thePRVs, shall be taken into account when determining their sizeto ensure the flow capacity required by 8.4.1.

8.4.3 Upstream pressure losses

8.4.3.1 The pressure drop in the vent line from the tank tothe PRV inlet shall not exceed 3 per cent of the valve set pressure at the calculated flow rate, in accordance with 8.4.1.

8.4.3.2 Pilot-operated PRVs shall be unaffected by inletpipe pressure losses when the pilot senses directly from thetank dome.

8.4.3.3 Pressure losses in remotely sensed pilot lines shallbe considered for flowing type pilots.

8.4.4 Downstream pressure losses

8.4.4.1 Where common vent headers and vent masts arefitted, calculations shall include flow from all attached PRVs.

8.4.4.2 The built-up back pressure in the vent piping fromthe PRV outlet to the location of discharge to the atmosphere,and including any vent pipe inter-connections that join othertanks, shall not exceed the following values:• For unbalanced PRVs: 10 per cent of MARVS; • For balanced PRVs: 30 per cent of MARVS; • For pilot operated PRVs: 50 per cent of MARVS.Alternative values provided by the PRV manufacturer may beaccepted.

8.4.5 To ensure stable PRV operation, the blow-downshall not be less than the sum of the inlet pressure loss and0,02 MARVS at the rated capacity.



LLOYD’S REGISTER4

Cargo Containment System Atmosphere Control

Section

9.1 Atmosphere control within the cargocontainment system

9.2 Atmosphere control within the hold spaces(cargo containment systems other than Type Cindependent tanks)

9.3 Environmental control of spaces surroundingType C independent tanks

9.4 Inerting

9.5 Inert gas production on board

9.1 Atmosphere control within the cargocontainment system

9.1.1 A piping system shall be arranged to enable eachcargo tank to be safely gas freed, and to be safely filled withcargo vapour from a gas free condition. The system shall bearranged to minimise the possibility of pockets of gas or airremaining after changing the atmosphere.

9.1.2 For flammable cargoes, the system shall bedesigned to eliminate the possibility of a flammable mixtureexisting in the cargo tank during any part of the atmospherechange operation by utilising an inerting medium as an intermediate step.

9.1.3 Piping systems that may contain flammablecargoes shall comply with 9.1.1 and 9.1.2.

9.1.4 A sufficient number of gas sampling points shall beprovided for each cargo tank and cargo piping system toadequately monitor the progress of atmosphere change. Gassampling connections shall be fitted with a single valve abovethe main deck, sealed with a suitable cap or blank. See also5.6.5.5.

9.1.5 Inert gas utilised in these procedures is to beprovided onboard the ship unit.

9.2 Atmosphere control within the hold spaces(cargo containment systems other thanType C independent tanks)

9.2.1 Interbarrier and hold spaces associated with cargocontainment systems for flammable gases requiring full orpartial secondary barriers shall be inerted with a suitable dryinert gas and kept inerted with make up gas provided by ashipboard inert gas generation system, or by shipboard storage, which shall be sufficient for normal consumption forat least 30 days.

9.2.2 Alternatively, subject to the restrictions specified inChapter 17, the spaces referred to in 9.2.1 requiring only apartial secondary barrier may be filled with dry air providedthat the ship unit maintains a stored charge of inert gas or isfitted with an inert gas generation system sufficient to inert thelargest of these spaces, and provided that the configuration ofthe spaces and the relevant vapour detection systems,together with the capability of the inerting arrangements,ensures that any leakage from the cargo tanks will be rapidlydetected and inerting effected before a dangerous conditioncan develop. Equipment for the provision of sufficient dry airof suitable quality to satisfy the expected demand shall beprovided.

9.2.3 For non flammable gases, the spaces referred to in9.2.1 and 9.2.2 may be maintained with a suitable dry air orinert atmosphere.

9.3 Environmental control of spaces surroundingType C independent tanks

9.3.1 Spaces surrounding cargo tanks that do not havesecondary barriers shall be filled with suitable dry inert gas ordry air and be maintained in this condition with make up inertgas provided by a shipboard inert gas generation system,shipboard storage of inert gas, or with dry air provided by suitable air drying equipment. If the cargo is carried at ambient temperature, the requirement for dry air or inert gasis not applicable.

9.4 Inerting

9.4.1 Inerting refers to the process of providing a non-combustible environment. Inert gases should be compatiblechemically and operationally at all temperatures likely to occurwithin the spaces and the cargo. The dew points of the gasesshall be taken into consideration.

9.4.2 Where inert gas is also stored for fire-fightingpurposes it shall be carried in separate containers and shallnot be used for cargo services.

9.4.3 Where inert gas is stored at temperatures below0°C, either as a liquid or as a vapour, the storage and supplysystem shall be designed so that the temperature of thestructure of the ship unit is not reduced below the limitingvalues imposed on it.

9.4.4 Arrangements to prevent the backflow of cargovapour into the inert gas system that are suitable for the cargocarried, shall be provided. If such plants are located inmachinery spaces or other spaces outside the cargo area,two non-return valves or equivalent devices and, in addition,a removable spool piece shall be fitted in the inert gas main inthe cargo area. When not in use, the inert gas system shallbe made separate from the cargo system in the cargo areaexcept for connections to the hold spaces or interbarrierspaces.




Cargo Containment System Atmosphere Control

9.4.5 The arrangements shall be such that each spacebeing inerted can be isolated and the necessary controls andrelief valves, etc, shall be provided for controlling pressure inthese spaces.

9.4.6 Where insulation spaces are continually suppliedwith an inert gas as part of a leak detection system, meansshall be provided to monitor the quantity of gas beingsupplied to individual spaces.

LR 9.4.1 Inert gas systems are to be so designed as tominimise the risk of ignition from the generation of staticelectricity by the system itself.

9.5 Inert gas production on board

9.5.1 The equipment shall be capable of producing inertgas with an oxygen content at no time greater than 5 per centby volume. A continuous reading oxygen content meter shallbe fitted to the inert gas supply from the equipment and shallbe fitted with an alarm set at a maximum of 5 per cent oxygencontent by volume.

9.5.2 An inert gas system shall have pressure controlsand monitoring arrangements appropriate to the cargocontainment system.

9.5.3 Spaces containing inert gas generation plants shallhave no direct access to accommodation spaces, servicespaces or control stations, but may be located in machineryspaces. Inert gas piping shall not pass through accommoda-tion spaces, service spaces or control stations.

9.5.4 Combustion equipment for generating inert gasshall not be located within the cargo area. Special consider-ation may be given to the location of inert gas generatingequipment using a catalytic combustion process.



LLOYD’S REGISTER2

Electrical Installations

Section

10.1 General requirements

10.2 Definitions


LR 10.1.1 For the hull structure and associated liquefiedgas cargo containment system, hazardous areas are to bedetermined, and electrical equipment is to be selected, inaccordance with IEC 60092: Electrical installations in ships –Part 502: Tankers - Special features. For topsides process facilities, the hazardous areas and electrical equipment selected for these areas should beestablished from suitable recognised hazardous area guidance, i.e., NFPA 497 Recommended Practice for theClassification of Flammable Liquids, Gases, or Vapors and ofHazardous (Classified) Locations for Electrical Installations inChemical Process Areas or EI IP-MCSP-P15 Model Code ofSafe Practice Part 15 Area Classification Code for installationshandling flammable fluids. However, whichever Standard isselected for the classification of topsides process hazards, itshould be ensured that it gives a suitably conservative deter-mination of the defined hazardous area. Reference shouldalso be made to the requirements stipulated within Pt 7, Ch 2.

10.1.1 Electrical installations shall be such as to minimisethe risk of fire and explosion from flammable products.

10.1.2 Electrical installations shall be in accordance withrecognised Standards. Reference is made to the recommen-dation published by the International ElectrotechnicalCommission, in particular to publication IEC 60092-502:1999.

10.1.3 Electrical equipment or wiring should not beinstalled in hazardous areas unless essential for operationalpurposes or safety enhancement.

10.1.4 Where electrical equipment is installed in hazardousareas as provided in 10.1.3 it shall be selected, installed andmaintained in accordance with Standards not inferior to IEC 60092-502:1999 (see Clause 6, Clause 7 and Clause 9).Equipment for hazardous areas shall be evaluated and certified or listed by an accredited testing authority or notifiedbody recognised by the Administration. Automatic isolation ofnon certified equipment on detection of a flammable gas shallnot be accepted as an alternative to the use of certified equip-ment.

10.1.5 To facilitate the selection of appropriate electricalapparatus and the design of suitable electrical installations,hazardous areas are divided into zones in accordance withrecognised Standards.

10.1.6 Electrical generation and distribution systems, andassociated control systems, shall be designed such that asingle fault will not result in the loss of ability to maintain cargotank pressures, as required by 7.8.1, and hull structuretemperature, as required by 4.19.1, within normal operatinglimits. Failure modes and effects shall be analysed and documented to a standard not inferior to IEC 60812.

10.1.7 The lighting system in hazardous areas shall bedivided between at least two branch circuits. All switches andprotective devices shall interrupt all poles or phases and shallbe either:(a) located in a non hazardous area; or(b) certified for use in the hazardous area where installed

in accordance with paragraph 6.5 of IEC 60092-502.

10.1.8 Electrical depth sounding or log devices andimpressed current cathodic protection system anodes orelectrodes shall be housed in gastight enclosures.

10.1.9 Submerged cargo pump motors and their supplycables may be fitted in cargo containment systems.Arrangements shall be made to automatically shut down themotors in the event of low liquid level. This may be accom-plished by sensing low pump discharge pressure, low motorcurrent, or low liquid level. This shutdown shall be alarmed atthe cargo control station. Cargo pump motors shall be capable of being isolated from their electrical supply duringgas-freeing operations.

LR 10.1.2 Electrical equipment that is located in eitherenclosed or open non hazardous areas and is to remain operational during catastrophic emergency conditions (i.e.major hydrocarbon release scenarios) is to be certified foroperation in Zone 1 hazardous areas. However if such emergency equipment is not certified for operation in Zone 1hazardous areas, the continued operation of this equipmentmaybe acceptable if it is demonstrated that the equipment isappropriately protected against potentially coming intocontact with a flammable atmosphere by being located in anenclosed safe area, with appropriate mitigating measures (i.e.enclosed safe area is equipped with gas tight barriers, gastight doors, rated gas dampers, suitable gas detection withinthe enclosure and its ventilation air intakes, etc.).

10.2 Definitions

For the purpose of this Chapter, unless expressly providedotherwise, the definitions below shall apply.

10.2.1 Hazardous area is an area in which an explosivegas atmosphere is or may be expected to be present, inquantities such as to require special precautions for theconstruction, installation and use of electrical apparatus.

10.2.1.1 Zone 0 hazardous area is an area in which anexplosive gas atmosphere is present continuously or ispresent for long periods.

10.2.1.2 Zone 1 hazardous area is an area in which anexplosive gas atmosphere is likely to occur in normal opera-tion.

10.2.1.3 Zone 2 hazardous area is an area in which anexplosive gas atmosphere is not likely to occur in normaloperation and, if it does occur, is likely to do so infrequentlyand for a short period only.




Electrical Installations

10.2.2 Non-hazardous area is an area in which an explosive gas atmosphere is not expected to be present inquantities such as to require special precautions for theconstruction, installation and use of electrical apparatus.

LR 10.2.1 See also Pt 7, Ch 2,1.2.



LLOYD’S REGISTER2

Fire Prevention and Extinction

Section

11.1 Fire safety requirements

11.2 Fire mains and hydrants

11.3 Water-spray system

11.4 Dry chemical powder fire-extinguishing systems

11.5 Enclosed spaces containing cargo handlingequipment

11.6 Firefighters’ outfits

11.1 Fire safety requirements

LR 11.1.1 Fire prevention and fighting measures for thehull, hull weather deck and liquefied gas offloading facilitiesare generally to be in compliance with the following Sections,which reflect the requirements of the International Code forthe Construction and Equipment of Ships Carrying LiquefiedGases in Bulk (IGC Code). However, alternative fire protectionand fire mitigating measures may be considered to be appropriate following assessment via the installation Fire andExplosion Evaluation (FEE), dependent upon the installation’sfire-fighting and safety philosophy. The various requirementsof Part 7 should also be fully referenced in connection withfire-fighting and fire mitigating measures.

11.1.1 In general, the requirements for tankers inSOLAS Chapter ll-2 are to apply to ship units covered by thisPart, irrespective of tonnage of the unit, with the exception ofthe following:

.1 regulations 4.5.1.6 and 4.5.10 do not apply;

.2 regulation 10.2 as applicable to cargo ships, andregulations 10.4 and 10.5 are in general to applyto the hull structure of the installation, as theywould apply to tankers of 2000 gross tonnageand over;

.3 regulation 10.5.6 is to apply to the hull structure;

.4 the following regulations of SOLAS Chapter II-2related to tankers do not apply and are replacedby the Chapters and Sections of this Part asdetailed below:Regulation Replaced by10.10 Part 11, 11.64.5.1.1 and 4.5.1.2 Part 11, Chapter 34.5.5 and 10.8 Part 11, 11.3 and 11.410.9 Part 11, 11.510.2 Part 11, 11.2.1 to 11.2.4

.5 regulations 13.3.4 and 13.4.3 shall apply to theship unit.

LR 11.1.2 Emergency escape breathing devices, in addition to those required by 11.1.1.5, should be available asdetermined by the escape, evacuation and rescue analysis ofthe unit.

LR 11.1.3 For the hull structure of the unit, all sources ofignition should be excluded from spaces where flammablevapour may be present, except as otherwise provided inChapter 10 and Chapter 16. For the topsides areas of theunit, sources of ignition should be minimised where practicable,but must always be certified for any defined hazardous area inwhich it is intended to operate. See also Pt 7, Ch 1 and 2 withregard to mitigation of ignition risks.

11.1.3 The provisions of this Section apply in conjunctionwith Chapter 3.

11.1.4 For the purposes of fire fighting, any weather deckareas above cofferdams, ballast or void spaces at the afterend of the aftermost hold space or at the forward end of theforwardmost hold space shall be included in the cargo area.

11.2 Fire mains and hydrants

11.2.1 All ship units, irrespective of size, with bulk liquefiedgas storage and/or vapour discharge and loading manifolds/facilities, carrying products specified in Chapter 19are in general to comply with the requirements of SOLASregulations ll-2/10.2, except that the required fire pumpcapacity and fire main and water service pipe diameter shouldnot be limited by the provisions of regulations ll-2/10.2.2.4.1and ll-2/10.2.1.3. When a fire pump is used as part of thewater spray system, as permitted by 11.3.3 of this Chapter,the capacity of this fire pump shall be such that these areascan be protected when simultaneously supplying two jets ofwater from fire hoses with 19 mm nozzles at a pressure of atleast 0,5 bar gauge for hydrants located at hull, hull weatherdeck and liquefied gas offloading facilities. For hydrant locatedon topsides facilities, the pressure should be at least 3,5 bargauge for two operational hydrants.

LR 11.2.1 In addition to 11.2.1, the fire pump capacityand fire main should be sized to supply all credible fire waterdemands associated with a credible installation fire scenariodetermined via the Fire and Explosion Evaluation (FEE).

11.2.2 The arrangements shall be such that at least twojets of water can reach any part of the deck in the cargo areaand those portions of the cargo containment system and tankcovers that are above the deck. The necessary number of firehydrants shall be located to satisfy the above arrangementsand to comply with the requirements of SOLAS regulations ll-2/10.2.1.5.1 and ll-2/10.2.3.3. The hose length should be15 m in hull machinery spaces and should not be greater than18 m in topsides areas, due to space constraints to enablethe hose to be laid out by a fire team in a fire incident.





11.2.3 Stop valves shall be fitted in any crossover providedand in the fire main or mains in a protected location, beforeentering the cargo area and at intervals ensuring isolation ofany damaged single section of the fire main, so that regulation11.2.2 can be complied with using not more than two lengthsof hoses from the nearest fire hydrant. The water supply tothe fire main serving the cargo area shall be a ring mainsupplied by the main fire pumps or a single main supplied byfire pumps positioned outside the cargo area. The main installation firewater pumps are to be positioned to ensure ahigh degree of firewater pump redundancy and firewatersupply integrity in potential major installation fire scenarios.

11.2.4 All nozzles provided for fire hoses shall be of anapproved dual purpose type, capable of producing either aspray or a jet. All pipes, valves, nozzles and other fittings inthe fire fighting systems shall be resistant to corrosion by seawater. Fixed piping, fittings and related components within thecargo area (except gaskets) shall be designed to withstand925°C and remain functional.

11.2.5 After installation, the pipes, valves, fittings andassembled system shall be subject to a tightness and functiontest.

11.3 Water-spray system

11.3.1 A water application system, which may be basedon water-spray nozzles, for cooling, fire prevention and crewprotection shall be installed to cover:

.1 exposed cargo tank domes, any exposed partsof cargo tanks and any part of cargo tank coversthat may be exposed to heat from fires in adjacent equipment containing cargo such asexposed booster pumps/heaters/re-gasificationor re-liquefaction plants, hereafter addressed asgas process units, positioned on weather decks;

.2 exposed on-deck storage vessels for flammableor toxic products;

.3 gas process units, positioned on deck;

.4 cargo liquid and vapour discharge and loadingconnections, including the presentation flangeand the area where their control valves are situated, which shall be at least equal to the areaof the drip trays provided;

.5 all exposed emergency shut down (ESD) valvesin the cargo liquid and vapour pipes, includingthe master valve for supply to gas consumers;

.6 exposed boundaries facing the cargo area, suchas bulkheads of superstructures and deckhousesnormally manned, cargo machinery spaces,store-rooms containing high fire risk items andcargo control rooms. Exposed horizontal bound-aries of these areas do not require protectionunless detachable cargo piping connections arearranged above or below. Boundaries ofunmanned forecastle structures not containinghigh fire risk items or equipment do not requirewater-spray protection;

.7 any semi-enclosed cargo machinery spaces andsemi-enclosed cargo motor room.

LR 11.3.1 Water spray fire-fighting measures for the hull,hull weather deck and liquefied gas offloading facilities aregenerally to be in compliance with the following Sections,which reflect the requirements of the International Code forthe Construction and Equipment of Ships Carrying LiquefiedGases in Bulk (IGC Code). However, alternative fire protectionand fire mitigating measures may be considered to be appropriate following assessment via the installation Fire andExplosion Evaluation (FEE), dependent upon the installation’sfire-fighting and safety philosophy. The various requirementsof Part 7 should also be fully referenced in connection withfire-fighting and fire mitigating measures.

11.3.2 The system shall be capable of covering all areasmentioned in 11.3.1.1 to 11.3.1.8, with a uniformly distributedwater application rate of at least 10 l/m2/minute for the largestprojected horizontal surfaces and 4 l/m2/minute for verticalsurfaces. For structures having no clearly defined horizontalor vertical surface, the capacity of the water application shallnot be less than the projected horizontal surface multiplied by10 l/m2/minute.On vertical surfaces, spacing of nozzles protecting lowerareas may take account of anticipated rundown from higherareas. Stop valves shall be fitted in the spray water applicationmain supply line(s), at intervals not exceeding 40 m, for thepurpose of isolating damaged sections. Alternatively, thesystem may be divided into two or more sections that may beoperated independently, provided the necessary controls arelocated together in a readily accessible position outside of thecargo area. A section protecting any area included in 11.3.1.1and 11.3.1.2 shall cover at least the entire athwartship tankgrouping in that area. Any gas process unit(s) included in11.3.1.3 may be served by an independent section.

11.3.3 The capacity of the water application pumps shallbe capable of simultaneous protection of any two completeathwartship tank groupings, including any gas process unitswithin these areas in addition to surfaces specified in11.3.1.4, 5, 6, 7 and 8. Alternatively, the main fire pumps maybe used for this service provided that their total capacity isincreased by the amount needed for the water-spray application system. In either case a connection, through astop valve, shall be made between the fire main and water-spray application system main supply line outside of the cargoarea. See also LR 11.2.1.

11.3.4 The maximum credible firewater demand should bedetermined in the installation Fire and Explosion Evaluation(FEE) based on the credible activation of water spray systemsdetailed in 11.3 and any additional topside module andhydrant demands.

LR 11.3.2 The installation main firewater pumps shouldbe sized suitably to supply the defined maximum credible fire-water demand. The installation design should incorporate asuitable allowance for firewater pump redundancy. Thisredundancy is to allow for failure of a firewater pump ondemand or loss of a firewater pump for maintenance withoutincurring potential lost production on the installation due tothe loss of firewater supply. Permanently manned hydrocar-bon installations typically have two 100 per cent or three 50 per cent firewater pumps designed to meet the installation’s defined largest credible firewater demandscenario (i.e., the installation’s 100 per cent firewater



LLOYD’S REGISTER2


demand). However, other configurations of firewater pumpsupply redundancy may be acceptable for an installation,subject to suitable demonstration (for example, normallyunmanned installations often do not have any dedicated fire-water pumps).

11.3.5 Water pumps normally used for other services maybe arranged to supply the water-spray application systemmain supply line.

11.3.6 All pipes, valves, nozzles and other fittings in thewater application systems shall be resistant to corrosion byseawater. Galvanised pipework may be considered for thisservice but copper nickel alloy or stainless steel pipeworkwhich is rated for marine/sea-water/fire-fighting service isrecommended for installations. Piping, fittings and relatedcomponents within the cargo area (except gaskets) shall bedesigned to withstand 925°C. The water application systemshall be arranged with in-line filters to prevent blockage ofpipes and nozzles. In addition means shall be provided toback flush the system with fresh water.

11.3.7 Remote starting of pumps supplying the waterapplication system and remote operation of any normallyclosed valves in the system shall be arranged in suitable locations outside the cargo area, adjacent to the accommo-dation spaces and readily accessible and operable in theevent of fire in the protected areas.

11.3.8 After installation, the pipes, valves, fittings andassembled system shall be subject to a tightness and functiontest.

LR 11.3.3 The provision of fixed firewater fire-fightingfacilities over topsides process module areas should beestablished based on the fire-fighting risks and philosophyderived for the installation via the Fire and ExplosionEvaluation (FEE).

11.4 Dry chemical powder fire-extinguishingsystems

LR 11.4.1 Dry chemical fire-fighting measures for thehull, hull weather deck and liquefied gas offloading facilitiesare generally to be in compliance with the following Sections,which reflect the requirements of the International Code forthe Construction and Equipment of Ships Carrying LiquefiedGases in Bulk (IGC Code). However, alternative fire protectionand fire mitigating measures may be considered to be appropriate following assessment via the installation Fire andExplosion Evaluation (FEE), dependent upon the installation’sfire-fighting and safety philosophy. The various requirementsof Part 7 should also be fully referenced in connection withfire-fighting and fire mitigating measures.

11.4.1 Dependent upon the conclusions of the Fire andExplosion Evaluation (FEE) and the installation’s fire-fighting andsafety philosophy, consideration for ship units should be given tothe provision of fixed dry chemical powder fire-extinguishingsystems, complying with the provisions of the FSS Code, for thepurpose of fire-fighting on the deck in the cargo area, includingall cargo liquid and vapour discharge and loading connectionson deck and cargo handling areas as applicable.

11.4.2 The system shall be capable of delivering powderfrom at least two hand hose lines, or a combination of monitor/hand hose lines, to any part of the exposed cargoarea, cargo liquid and vapour piping, load/unload connectionsand exposed gas process units.

11.4.3 The dry chemical powder fire-extinguishing systemshall be designed with not less than two independent units.Any part required to be protected by 11.4.2 shall be capableof being reached from not less than two independent unitswith associated controls, pressurising medium fixed piping,monitors or hand hose lines. A monitor shall be arranged toprotect any load/unload connection areas and be capable ofactuation and discharge both locally and remotely. The monitor is not required to be remotely aimed if it can deliverthe necessary powder to all required areas of coverage froma single position. One hose line shall be provided at both portand starboard side at the end of the cargo area facing theaccommodation and readily available from the accommoda-tion.

11.4.4 The dry chemical powder fire-extinguishingsystem(s) shall be of an approved type and comply with theFSS Code.

11.4.5 The capacity of a monitor shall be not less than 10 kg/s. Hand hose lines shall be non-kinkable and be fittedwith a nozzle capable of on/off operation and discharge at arate not less than 3,5 kg/s. The maximum discharge rate shallallow operation by one man. The length of a hand hose lineshall not exceed 33 m. Where fixed piping is providedbetween the powder container and a hand hose line or monitor, the length of piping shall not exceed that lengthwhich is capable of maintaining the powder in a fluidised stateduring sustained or intermittent use, and which can bepurged of powder when the system is shut down. Hand hoselines and nozzles shall be of weather-resistant construction orstored in weather resistant housing or covers and be readilyaccessible.

11.4.6 Hand hose lines shall be considered to have amaximum effective distance of coverage equal to the length ofhose. Special consideration shall be given where areas to beprotected are substantially higher than the monitor or handhose reel locations. See also LR 11.4.1 regarding topsidesprocess areas.

11.4.7 Ship units fitted with bow, stern load/unloadconnections shall be provided with independent dry powderunits protecting the cargo liquid and vapour piping, aft orforward of the cargo area, by hose lines and a monitor coveringthe bow, stern load/unload complying with the requirementsof 11.4.1 to 11.4.6.

11.4.8 After installation, the pipes, valves, fittings andassembled systems shall be subjected to a tightness test andfunctional testing of the remote and local release stations. Theinitial testing shall also include a discharge of sufficientamounts of dry chemical powder to verify that the system is inproper working order. All distribution piping shall be blownthrough with dry air to ensure that the piping is free ofobstructions.





11.5 Enclosed spaces containing cargo handlingequipment

11.5.1 Enclosed spaces meeting the criteria of cargomachinery spaces in 1.2, and the cargo motor room withinthe cargo area of any ship unit, shall be provided with a fixedfire extinguishing system complying with the provisions of theFSS Code and taking into account the necessary concentra-tions/application rate required for extinguishing gas fires.

LR 11.5.1 Cargo machinery spaces shall be protectedby an appropriate fire-extinguishing system for the cargocarried. The system is to be approved by the Administration.

11.5.2 The fire risks associated with the turret compart-ments of any ship unit are to be fully assessed within theinstallation Fire and Explosion Evaluation (FEE). The fire-fighting/mitigating measures associated with the turret (i.e.,water spray, passive fire protection, isolation and blowdown,etc.) are to be based upon the fire risks determined within theFire and Explosion Evaluation (FEE) and should be in line withthe overall installation’s fire-fighting and safety philosophy.

11.6 Firefighters’ outfits

LR 11.6.1 In addition to the requirements outlined in thisSection, further facilities may be required on the installationbased on the fire-fighting risks and philosophy derived for theinstallation via the Fire and Explosion Evaluation (FEE).

11.6.1 Every ship unit shall carry firefighter’s outfits complyingwith the requirements of SOLAS regulation ll-2/10.10 as follows:

Total cargo capacity Number of outfits5000 m3 and below 4Above 5000 m3 5

11.6.2 Additional requirements for safety equipment aregiven in Chapter 14.

11.6.3 Any breathing apparatus required as part of a fire-fighter’s outfit shall be a self-contained compressedair-operated breathing apparatus having a capacity of at least1200 l of free air.



LLOYD’S REGISTER4

Artificial Ventilation in the Cargo Area

Section

12.1 Spaces required to be entered during normalcargo handling operations

12.2 Spaces not normally entered

12.1 Spaces required to be entered during normalcargo handling operations

The requirements of this Chapter replace the requirementsSOLAS Regulations II-2/4.5.2.6 and 4.5.4.1, as amended.

12.1.1 Electric motor rooms, cargo compressor and pumprooms, spaces containing cargo handling equipment andother enclosed spaces where cargo vapours may accumu-late shall be fitted with fixed artificial ventilation systemscapable of being controlled from outside such spaces. Theventilation shall be run continuously to prevent the accumula-tion of toxic and/or flammable vapours, with a means ofmonitoring acceptable to the Administration to be provided. Awarning notice requiring the use of such ventilation prior toentering shall be placed outside the compartment.

12.1.2 Artificial ventilation inlets and outlets shall bearranged to ensure sufficient air movement through the spaceto avoid accumulation of flammable, toxic or asphixiantvapours, and to ensure a safe working environment.

12.1.3 The ventilation system shall have a capacity of notless than 30 changes of air per hour, based upon the totalvolume of the space. As an exception, non-hazardous cargocontrol rooms may have eight changes of air per hour.

12.1.4 Where a space has an opening into an adjacentmore hazardous space or area, it shall be maintained at anover-pressure. It may be made into a less hazardous spaceor non-hazardous space by over-pressure protection inaccordance with recognised Standards.

12.1.5 Ventilation ducts, air intakes and exhaust outletsserving artificial ventilation systems shall be positioned inaccordance with recognised Standards.

12.1.6 Ventilation ducts serving hazardous areas shall notbe led through accommodation, service and machineryspaces or control stations, except as allowed in Chapter 16.

12.1.7 Electric motors driving fans shall be placed outsidethe ventilation ducts that may contain flammable vapours.Ventilation fans shall not produce a source of ignition in eitherthe ventilated space or the ventilation system associated withthe space. For hazardous areas, ventilation fans and ducts,adjacent to the fans, shall be of non sparking construction,as defined below:

.1 impellers or housing of non-metallic construction,with due regard being paid to the elimination ofstatic electricity;

.2 impellers and housing of non-ferrous materials;

.3 impellers and housing of austenitic stainlesssteel; and

.4 ferrous impellers and housing with not less than13 mm design tip clearance.

Any combination of an aluminium or magnesium alloy fixed orrotating component and a ferrous fixed or rotating compo-nent, regardless of tip clearance, is considered a sparkinghazard and shall not be used in these places.

12.1.8 Where fans are required by this Chapter, fullrequired ventilation capacity for each space shall be availableafter failure of any single fan or spare parts shall be providedcomprising; a motor, starter spares and complete rotatingelement, including bearings of each type.

12.1.9 Protection screens of not more than 13 mm squaremesh shall be fitted to outside openings of ventilation ducts.

12.1.10 Where spaces are protected by pressurisation theventilation shall be designed and installed in accordance withrecognised Standards.

LR 12.1.1 For 12.1.4, 12.1.5 and 12.1.10 reference ismade to the recommendation published by the InternationalElectrotechnical Commission: in particular to the publicationIEC 60092-502:1999.

12.2 Spaces not normally entered

Enclosed spaces where cargo vapours may accumulate shallbe capable of being ventilated to ensure a safe environmentwhen entry into them is necessary. This shall be capable ofbeing achieved without the need for prior entry.

LR 12.2.1 Ventilation systems are to be capable of useprior to entry and during occupation.For permanent installations, the capacity of 8 air changes perhour shall be provided and for portable systems, the capacityof 16 air changes per hour.Fans or blowers shall be clear of personnel access openings,and shall comply with 12.1.7.

LR 12.2.2 Enclosed spaces in the cargo area used as laboratories, workshops, decontamination cubicles or fordomestic purposes are to comply with the requirements of12.1.1.

LR 12.2.3 Particulars of the type and number of portablefans, their arrangements and means of attachment are to besubmitted for consideration in relation to the internal andexternal arrangements of the space concerned.




Document1 12/04/02 15:23 Page 1

Instrumentation and Automation Systems

Section

13.1 General

13.2 Level indicators for cargo tanks

13.3 Overflow control

13.4 Pressure monitoring

13.5 Temperature indicating devices

13.6 Gas detection

13.7 Additional requirements for containmentsystems requiring a secondary barrier

13.8 Automation systems

13.9 System integration

13.1 General

13.1.1 Each cargo tank shall be provided with a means forindicating level, pressure and temperature of the cargo.Pressure gauges and temperature indicating devices shall beinstalled in the liquid and vapour piping systems, in cargorefrigeration installations.

13.1.2 If loading and unloading of the ship unit isperformed by means of remotely controlled valves andpumps, all controls and indicators associated with a givencargo tank shall be concentrated in one control position.

13.1.3 Instruments shall be tested to ensure reliabilityunder the working conditions and recalibrated at regular intervals. Test procedures for instruments and the intervalsbetween recalibration shall be in accordance with manufac-turer's recommendations, or at a period developed by riskassessment once maintenance data is available.

13.2 Level indicators for cargo tanks

13.2.1 Each cargo tank shall be fitted with liquid levelgauging device(s), arranged to ensure a level reading isalways obtainable whenever the cargo tank is operational.The device(s) shall be designed to operate throughout thedesign pressure range of the cargo tank and at temperatureswithin the cargo operating temperature range.

13.2.2 Where only one liquid level gauge is fitted it shall bearranged so that it can be maintained in an operational condition without the need to empty or gas-free the tank.

13.2.3 Cargo tank liquid level gauges may be of the followingtypes, subject to special requirements for particular cargoesshown in column ‘g’ in the table of Chapter 19:

.1 indirect devices, which determine the amount ofcargo by means such as weighing or in-line flowmetering;

.2 closed devices, which do not penetrate the cargotank, such as devices using radio-isotopes orultrasonic devices;

.3 closed devices, which penetrate the cargo tank,but which form part of a closed system and keepthe cargo from being released, such as float typesystems, electronic probes, magnetic probes andbubble tube indicators. If a closed gaugingdevice is not mounted directly on to the tank, itshall be provided with a shutoff valve located asclose as possible to the tank.

.4 restricted devices, which penetrate the tank andwhen in use permit a small quantity of cargovapour or liquid to escape to the atmosphere,such as fixed tube and slip tube gauges. Whennot in use, the devices shall be kept completelyclosed. The design and installation shall ensurethat no dangerous escape of cargo can takeplace when opening the device. Such gaugingdevices shall be so designed that the maximumopening does not exceed 1,5 mm diameter orequivalent area unless the device is provided withan excess flow valve.

13.3 Overflow control

13.3.1 Each cargo tank shall be fitted with a high liquidlevel alarm operating independently of other liquid level indicators and giving an audible and visual warning when activated.

13.3.2 An additional sensor operating independently of thehigh liquid level alarm shall automatically actuate a shutoffvalve in a manner that will both avoid excessive liquid pressure in the loading line and prevent the tank from becomingliquid full.

13.3.3 The emergency shutdown valve referred to in 5.5and 18.10 may be used for this purpose. If another valve isused for this purpose, the same information as referred to in18.10.2.1.3 shall be available onboard. During loading, when-ever the use of these valves may possibly create a potentialexcess pressure surge in the loading system, alternativearrangements such as limiting the loading rate shall be used.

13.3.4 The position of the sensors in the tank shall becapable of being verified before commissioning. At first loading, and after each dry-docking, testing of high levelalarms shall be conducted by raising the cargo liquid level inthe cargo tank to the alarm point.

13.3.5 All elements of the level alarms, including the electrical circuit and the sensor(s), of the high, and overfillalarms, shall be capable of being functionally tested. Systemsshall be tested prior to cargo operation in accordance with18.6.2.





13.4 Pressure monitoring

13.4.1 The vapour space of each cargo tank shall beprovided with a direct reading gauge. Additionally, an indirectindication is to be provided at the control position required by13.1.2. Maximum and minimum allowable pressures shall beclearly indicated.

13.4.2 A high-pressure alarm and, if vacuum protection isrequired, a low-pressure alarm shall be provided on the navigating bridge and at the control position required by13.1.2. Alarms shall be activated before the set pressures arereached.

13.4.3 For cargo tanks fitted with PRVs, which can be setat more than one set pressure in accordance with 8.2.7, high-pressure alarms shall be provided for each set pressure. Apermit to work system advising which PRV setting is in use isto be provided.

13.4.4 Each cargo-pump discharge line and each liquidand vapour cargo manifold shall be provided with at least onepressure indicator.

13.4.5 Local-reading manifold pressure indication shall beprovided to indicate the pressure between manifold valves ofthe ship unit and hose connections to the shuttle tanker.

13.4.6 Hold spaces and interbarrier spaces without openconnection to the atmosphere shall be provided with pressureindication.

13.4.7 All pressure indications provided shall be capableof indicating throughout the operating pressure range.

13.5 Temperature indicating devices

13.5.1 Each cargo tank shall be provided with at least twodevices for indicating cargo temperatures, one placed at thebottom of the cargo tank and the second near the top of thetank, below the highest allowable liquid level. The lowesttemperature for which the cargo tank has been designed,consistent with the assigned class notation, shall be clearlyindicated by means of a sign on or near the temperature indicating devices.

13.5.2 The temperature indicating devices shall be capable of providing temperature indication across theexpected cargo operating temperature range of the cargotanks.

13.5.3 Where thermowells are fitted they shall bedesigned to minimise failure; due to fatigue in normal service.

13.6 Gas detection

13.6.1 Gas detection equipment shall be installed to monitor the integrity of the cargo containment, cargo handlingand ancilliary systems in accordance with this Section.However, the overall provision of gas detection on the installation should be defined based on ignition risk mitigating measures and philosophy derived for the installa-tion via the Fire and Explosion Evaluation (FEE).

13.6.2 A permanently installed system of gas detectionand audible and visual alarms shall be fitted in:

.1 all enclosed cargo and cargo machinery spaces(including turrets compartments) or similar enclosures containing gas piping, gas equipmentor gas consumers;

.2 other enclosed or semi-enclosed spaces wherecargo vapours may accumulate including interbarrier spaces and hold spaces for indepen-dent tanks other than Type C;

.3 airlocks;

.4 the spaces in gas fired internal combustionengines, referred to in 16.7.3.3;

.5 ventilation hoods and gas ducts required byChapter 16;

.6 cooling/heating circuits, as required by 7.8.4;

.7 inert gas generator supply headers;

.8 motor rooms for cargo handling machinery.However, the overall provision of gas detection on the instal-lation should be defined based on ignition risk mitigatingmeasures and philosophy derived for the installation via theFire and Explosion Evaluation (FEE).The various fire and gas detectors should feed signals into arobust fire and gas detection system/panel, in accordance withthe requirements of Pt 7, Ch 1,2. High level fire and gassignals, along with process hazard signals are then to feed intoa robust Emergency Shut-down (ESD) System, in accordancewith the requirements of Chapter 18 and Pt 7, Ch 1,7.

13.6.3 Gas detection equipment shall be designed,installed and tested in accordance with IEC 60079-29-1 –Explosive atmospheres – Gas detectors – Performancerequirements of detectors for flammable gases and shall besuitable for the cargoes to be stored in accordance withcolumn ‘f’ in table of Chapter 19.

13.6.4 For ship units permitted to store non-flammableproducts, oxygen deficiency monitoring shall be fitted in cargomachinery spaces and cargo tank hold spaces. Furthermore,oxygen deficiency monitoring equipment shall be installed inenclosed or semi-enclosed spaces containing equipment thatmay cause an oxygen-deficient environment such as nitrogengenerators, inert gas generators or nitrogen cycle refrigerantsystems.

13.6.5 Permanently installed gas detection shall be of thecontinuous detection type, capable of immediate response.Where not used to activate safety shutdown functionsrequired by 13.6.7 and Chapter 16, the sampling type detec-tion may be accepted.



LLOYD’S REGISTER2


13.6.6 When sampling type gas detection equipment isused the following requirements shall be met:

.1 the gas detection equipment shall be capable ofcontinuous monitoring at each sampling headlocation; and

.2 individual sampling lines from sampling heads tothe detection equipment shall be fitted; and

.3 pipe runs from sampling heads shall not be ledthrough non-hazardous spaces except aspermitted by 13.6.7.

13.6.7 The gas detection equipment may be located in anon-hazardous space, provided that the detection equipmentsuch as sample piping, sample pumps, solenoids andanalysing units are located in a fully enclosed steel cabinetwith the door sealed by a gasket. The atmosphere within theenclosure shall be continuously monitored. At gas concen-trations of 20 per cent lower flammable limit (LFL) inside theenclosure an alarm shall be activated in accordance with therequirements of 13.6.11 via the fire and gas system. At gasconcentrations above 30 per cent lower flammable limit (LFL)inside the enclosure, the gas detection equipment is to beautomatically shut down but the alarm in accordance with13.6.11 is to be maintained until gas concentrations dropbelow 20 per cent lower flammable limit (LFL) inside theenclosure.

13.6.8 Where the enclosure cannot be arranged directlyon the forward bulkhead, sample pipes shall be of steel orequivalent material and are to be routed on their shortest way.Detachable connections, except for the connection points forisolating valves required in 13.6.9 and analysing units, are notpermitted.

LR 13.6.1 In liquefied gas storage spaces, includingcargo hold spaces, the sampling heads are not to be locatedwhere bilge water can collect.

13.6.9 When gas sampling equipment is located in non-hazardous space, a flame arrester and a manual isolatingvalve shall be fitted in each of the gas sampling lines. Theisolating valve shall be fitted on the non-hazardous side.Bulkhead penetrations of sample pipes between hazardousand non-hazardous areas shall maintain the integrity of thedivision penetrated. The exhaust gas shall be discharged tothe open air in a non-hazardous location.

LR 13.6.2 Gas analysing equipment and associatedsampling pumps and solenoid valves located in a gas-safespace are to be enclosed in a gastight steel cabinet,monitored by its own sampling point. At gas concentrations of20 per cent lower flammable limit (LFL) inside the enclosure,an alarm is to be activated in accordance with therequirements of 13.6.11 via the fire and gas system. At gasconcentrations above 30 per cent LFL inside the steel cabinetthe entire gas analysing unit is to be automatically shut downbut the alarm in accordance with 13.6.11 is to be maintaineduntil gas concentrations drop below 20 per cent lowerflammable limit (LFL) inside the enclosure.

13.6.10 In every installation, the number and the positionsof detection heads shall be determined with due regard to thesize and layout of the compartment, the compositions anddensities of the products intended to be carried and the dilution from compartment purging or ventilation and stagnantareas.

13.6.11 Any alarms status within a gas detection systemrequired by this Section shall initiate an audible and visiblealarm;

.1 on the navigation bridge (if provided on the installation);

.2 at the relevant control station(s) where continu-ous monitoring of the gas levels is recorded; and

.3 at the gas detector readout location.

13.6.12 In the case of flammable products, the gas detec-tion equipment provided for hold spaces and interbarrierspaces that are required to be inerted shall be capable ofmeasuring gas concentrations of 0 per cent to 100 per centby volume.

13.6.13 For membrane containment systems, the primaryand secondary insulation spaces are to have independentinert gas systems and independent gas detection systems.The alarm in the secondary insulation space shall be set at 30 per cent of the LFL in air, that in the primary space shall beset at a value approved by LR.

13.6.14 For other spaces described by 13.6.2, alarms areto be activated when the vapour concentration reaches a relatively low per cent LFL (typically 20 per cent of the LFL inair). The fire and gas detection system stipulated by Pt 7, Ch 1,2 shall initiate safety functions required by Chapter 18and Pt 7, Ch 1,7 if the vapour concentration reaches 60 percent LFL. However, for gas detection within ventilation ducts,a low level alarm setting of 10 per cent of the LFL in air is tobe utilised, due to the potential to generate laminar flow withinductwork. Within turbine hoods and other spaces with potential high air change rates, a low level alarm setting of 10 per cent of the LFL shall be utilised with initiation of emergency shut-down actions if vapour concentrations rates20 per cent of the LFL. The crankcases of internal combus-tion engines that can run on gas shall be arranged to alarmbefore 100 per cent LFL.

13.6.15 Gas detection equipment shall be so designed thatit may readily be tested. Testing and calibration shall becarried out at regular intervals. Suitable equipment for thispurpose shall be carried on board and be used in accordancewith the manufacturer's recommendations. Permanentconnections for such test equipment shall be fitted.

13.6.16 Every ship unit shall be provided with at least twosets of portable gas detection equipment that meet therequirement of 13.6.3 or an acceptable national or interna-tional Standard.

13.6.17 A suitable instrument for the measurement ofoxygen levels in inert atmospheres shall be provided.





13.7 Additional requirements for containmentsystems requiring a secondary barrier

13.7.1 Integrity of barriersWhere a secondary barrier is required, permanently installedinstrumentation shall be provided to detect when the primarybarrier fails to be liquid tight at any location or when liquidcargo is in contact with the secondary barrier at any location.This instrumentation shall consist of appropriate gas detecting devices according to 13.6. However, the instru-mentation need not be capable of locating the area whereliquid cargo leaks through the primary barrier or where liquidcargo is in contact with the secondary barrier.

13.7.2 Temperature indication devices

13.7.2.1 The number and position of temperature indicatingdevices shall be appropriate to the design of the containmentsystem and cargo operation requirements.

13.7.2.2 When cargo is carried in a cargo containmentsystem with a secondary barrier, at a temperature lower than–55°C, temperature indicating devices shall be providedwithin the insulation or on the hull structure adjacent to cargocontainment systems. The devices shall give readings at regular intervals and, where applicable, alarm of temperaturesapproaching the lowest for which the hull steel is suitable.

13.7.2.3 If cargo is to be carried at temperatures lower than–55°C, the cargo tank boundaries, if appropriate for thedesign of the cargo containment system, shall be fitted with asufficient number of temperature indicating devices to verifythat unsatisfactory temperature gradients do not occur.

13.7.2.4 For the purposes of design verification and deter-mining the effectiveness of the initial cooldown procedure,one tank shall be fitted with devices in excess of thoserequired in 13.7.2.1. These devices may be temporary orpermanent.

13.8 Automation systems

13.8.1 The requirements of this Section shall apply whereautomation systems are used to provide instrumentedcontrol, monitoring/alarm or safety functions required by thisPart.

13.8.2 Automation systems shall be designed, installedand tested in accordance with recognised Standards.

13.8.3 Hardware shall be capable of being demonstratedto be suitable for use in the marine environment by typeapproval or other means.

13.8.4 Software shall be designed and documented forease of use, including testing, operation and maintenance.

13.8.5 The user interface shall be designed such that theequipment under control can be operated in a safe and effective manner at all times.

13.8.6 Automation systems shall be arranged such that ahardware failure or an error by the operator does not lead toan unsafe condition. Adequate safeguards against incorrectoperation shall be provided.

13.8.7 Appropriate segregation shall be maintainedbetween control, monitoring/alarm and safety functions tolimit the effect of single failures. This shall be taken to includeall parts of the Automation Systems that are required toprovide specified functions, including connected devices andpower supplies.

13.8.8 Automation Systems shall be arranged such thatthe configuration is protected against unauthorised or unin-tended change.

13.8.9 A management of change process shall be appliedto safeguard against unexpected consequences of modifica-tion. Records of configuration changes and approvals shallbe maintained onboard.

13.8.10 Processes for the development and maintenanceof integrated systems shall be in accordance with recognisedStandards. These processes shall include appropriate riskidentification and management.

13.9 System integration

13.9.1 Essential safety functions shall be designed suchthat risks of harm to personnel or damage to the installation orthe environment are reduced to a level acceptable to theadministration, both in normal operation and under faultconditions. Functions shall be designed to fail safe. Roles andresponsibilities for integration of systems shall be clearlydefined and agreed by all relevant stakeholders.

13.9.2 Functional requirements of each component sub-system shall be clearly defined to ensure that the integratedsystem meets functional and specified safety requirementsand takes account of any limitations of the equipment undercontrol.

13.9.3 Key hazards of the integrated system shall be identified using appropriate risk based techniques.

13.9.4 The integrated system shall have a suitable meansof reversionary control.

13.9.5 Failure of one part of the integrated system shallnot affect the functionality of other parts except for thosefunctions directly dependent on the defective part.

13.9.6 Operation with an integrated system shall be atleast as effective as it would be with individual stand aloneequipment or systems.

13.9.7 The integrity of essential machinery or systems,during normal operation and fault conditions, shall be demon-strated.



LLOYD’S REGISTER4

Personnel Protection

Section

14.1 Protective equipment

14.2 First-aid equipment

14.3 Safety equipment

14.1 Protective equipment

LR 14.1.1 The requirements of this Chapter are not clas-sification requirements. However, in cases where Lloyd’sRegister (LR) is requested to do so by an Owner, Operator orDuty Holder, the requirements of this Chapter will be applied,together with any amendments or interpretations adopted bythe appropriate National Authority.

LR 14.1.2 The requirements of this Chapter are consid-ered to be minimum requirements applicable to installationswith bulk liquefied gas storage and/or vapour discharge andloading/offloading manifolds/facilities. However, additionalequipment for personnel protection above the requirementsoutlined within this Chapter may be required on an installa-tion and these should be defined as part of the risk mitigatingmeasures and philosophy derived for the installation.

14.1.1 Suitable protective equipment, including eyeprotection to a recognised National or International Standard,shall be provided for protection of crew members engaged innormal cargo operations, taking into account the character-istics of the products being carried.

14.1.2 Personal protective and safety equipment requiredin this chapter shall be kept in suitable, clearly marked lockerslocated in readily accessible places.

14.1.3 The compressed air equipment shall be inspectedat least once a month by a responsible officer and the inspec-tion logged in the ship unit’s records. This equipment shallalso be inspected and tested by a competent person at leastonce a year.

14.2 First-aid equipment

14.2.1 A stretcher that is suitable for hoisting an injuredperson from spaces below deck shall be kept in a readilyaccessible location.

14.2.2 The ship unit shall have onboard medical first aidequipment, including oxygen resuscitation equipment, basedon the requirements of the Medical First Aid Guide (MFAG) forthe intended cargoes.

14.3 Safety equipment

14.3.1 Sufficient, but not less than three complete sets ofsafety equipment shall be provided in addition to the fire-fighter’s outfits required by 11.6.1. Each set shall provideadequate personal protection to permit entry and work in agas-filled space. This equipment shall take into account thenature of the intended cargoes.

14.3.2 Each complete set of safety equipment shallconsist of:

.1 one self contained positive pressure air breathingapparatus incorporating full face mask, not usingstored oxygen and having a capacity of at least1 200 litres of free air. Each set shall be compat-ible with that required by 11.6.1.

.2 protective clothing, boots and gloves to a recog-nised standard.

.3 steel cored rescue line with belt; and

.4 explosion proof lamp.

14.3.3 An adequate supply of compressed air shall beprovided and shall consist of:

.1 At least one fully charged spare air bottle for eachbreathing apparatus required by 14.3.1, in accor-dance with the requirements of 11.6.1;

.2 an air compressor of adequate capacity capableof continuous operation, suitable for the supplyof high pressure air of breathable quality, and

.3 a charging manifold capable of dealing with suffi-cient spare breathing apparatus air bottles for thebreathing apparatus required by 14.3.1.




Document1 12/04/02 15:23 Page 1

Filling Limits for Cargo Tanks

Section

15.1 Definitions


15.3 Default filling limit

15.4 Determination of increased filling limit

15.5 Maximum loading limit

15.6 Information to be provided to the Operator

15.1 Definitions

15.1.1 Filling limit (FL) means the maximum liquid volumein a cargo tank relative to the total tank volume when theliquid cargo has reached the reference temperature.

15.1.2 Loading limit (LL) means the maximum allowableliquid volume relative to the tank volume to which the tankmay be loaded.

15.1.3 Reference temperature means (for the purposes ofthis Chapter only):

.1 When no cargo vapour pressure/temperaturecontrol, as referred to in Chapter 7, is provided,the temperature corresponding to the vapourpressure of the cargo at the set pressure of thePRVs.

.2 When a cargo vapour pressure/temperaturecontrol, as referred to in Chapter 7, is provided,the temperature of the cargo upon termination ofloading, during transport or at unloading,whichever is the greatest.

LR 15.1.1 Ambient design temperatures for air and sea-water are at their highest daily mean temperatures for theunit’s proposed area of operation based on the 100 year aver-age return period. The ambient temperatures are to berounded up to the nearest degree Celsius. For initial design,the ambient temperatures may be taken as 45°C for air and32°C for sea-water.


The maximum filling limit of cargo tanks shall be so deter-mined that the vapour space has a minimum volume atreference temperature allowing for:

.1 tolerance of instrumentation such as level andtemperature gauges

.2 volumetric expansion of the cargo between thePRV set pressure and the maximum allowablerise stated in 8.4

.3 an operational margin to account for liquiddrained back to cargo tanks after completion ofloading, operator reaction time and closing timeof valves, see 5.5 and 18.10.2.1.4.

15.3 Default filling limit

The default value for the filling limit (FL) of cargo tanks is 98per cent at the reference temperature. Exceptions to thisvalue shall meet the requirements of 15.4.

15.4 Determination of increased filling limit

15.4.1 A filling limit greater than the limit of 98 per centspecified in 15.3 on condition that, under the trim and listconditions specified in 8.2.17 may be permitted, providing:

.1 no isolated vapour pockets are created within thecargo tank

.2 the PRV inlet arrangement shall remain in thevapour space

.3 allowances need to be provided for:.1 volumetric expansion of the liquid cargo due

to the pressure increase from the MARVS tofull flow relieving pressure in accordance with8.4.1

.2 an operational margin of minimum 0,1 percent of tank volume

.3 tolerances of instrumentation such as leveland temperature gauges.

15.4.2 In no case shall a filling limit exceeding 99,5 percent at reference temperature be permitted.

15.5 Maximum loading limit

15.5.1 The maximum loading limit (LL) to which a cargotank may be loaded shall be determined by the followingformula:

LL = FL

where:LL = loading limit as defined in 15.1.2 expressed in per

cent;FL = filling limit as specified in 15.3 or 15.4 expressed in

per cent;ρR = relative density of cargo at the reference tempera-

ture; andρL = relative density of cargo at the loading temperature.

15.5.2 The Administration may allow Type C tanks to beloaded according to the formula in 15.5.1 with the relativedensity ρR as defined below, provided that the tank ventsystem has been approved in accordance with 8.2.18.ρR = relative density of cargo at the highest temperature

that the cargo may reach upon termination of load-ing, during storage, or at unloading, under theambient design temperature conditions describedin LR 15.1.1.

15.6 Information to be provided to the Operator

15.6.1 A document shall be provided to the unit specify-ing the maximum allowable loading limits for each cargo tankand product, at each applicable loading temperature andmaximum reference temperature. The information in thisdocument shall be approved by LR.

ρRρL




Filling Limits for Cargo Tanks

15.6.2 Pressures at which the PRVs have been set shallalso be stated in the document.

15.6.3 A copy of the above document shall be perma-nently kept onboard by the Operator.



LLOYD’S REGISTER2

Use of Cargo as Fuel

Section

16.1 General

16.2 Use of cargo vapour as fuel

16.3 Arrangement of spaces containing gasconsumers

16.4 Fuel gas supply

16.5 Fuel gas plant and related storage tanks

16.6 Special requirements for main boilers

16.7 Special requirements for gas-fired internalcombustion engines

16.8 Special requirements for gas turbines

16.9 Alternative fuels and technologies

LR 16.10 Survey

16.1 General

Except as provided for in 16.9, Methane (LNG) is the onlycargo whose vapour or boil off gas may be utilised in machineryspaces of category A, and in these spaces it may be utilisedonly in systems such as boilers, inert gas generators, internalcombustion engines, gas combustion units (GCU) and gasturbines.

LR 16.1.1 In addition to the requirements of this Chapterin respect of using LNG as a fuel, the requirements of Pt 5,Ch 15 are also to be complied with.

LR 16.1.2 The following plans are to be submitted forconsideration:• General arrangement of plan.• Gas piping systems, together with details of interlocking

and safety devices.• Gas heaters.• Gas compressors and their prime movers.• Gas storage pressure vessels.• Gas and oil fuel burning arrangements.

16.2 Use of cargo vapour as fuel

This section addresses the use of cargo vapour as fuel insystems such as boilers, inert gas generators, internalcombustion engines, GCUs and gas turbines.

16.2.1 For vaporised LNG, the fuel supply system shallcomply with the requirements of 16.4.1, 16.4.2 and 16.4.3.

16.2.2 For vaporised LNG, gas consumers shall exhibit novisible flame and shall maintain the uptake exhaust tempera-ture below 535°C.

16.3 Arrangement of spaces containing gasconsumers

16.3.1 Spaces in which gas consumers are located shallbe fitted with a mechanical ventilation system that is arrangedto avoid areas where gas may accumulate, taking intoaccount the density of the vapour and potential ignitionsources. The ventilation system shall be separated from thoseserving other spaces.

16.3.2 Gas detectors shall be fitted in these spaces,particularly where air circulation is reduced. The gas detec-tion system shall comply with the requirements of Chapter 13.

16.3.3 Electrical equipment located in the double wall pipeor duct specified in 16.4.3 shall comply with the requirementsof Chapter 10.

16.3.4 All vents and bleed lines that may contain or becontaminated by gas fuel shall be routed to a safe locationexternal to the machinery space and be fitted with a flamescreen.

16.4 Fuel gas supply

16.4.1 General

The requirements of 16.4 apply to fuel gas supply pipingoutside of the cargo area. Fuel piping shall not pass throughaccommodation spaces, service spaces, electrical equipmentrooms or control stations. The routeing of the pipeline shalltake into account potential hazards due to mechanicaldamage, such as stores or machinery handling areas.Provision shall be made for inerting and gas-freeing thatportion of the gas fuel piping systems located in the machineryspace.

16.4.2 Leak detection Continuous monitoring and alarms shall be provided to indicate a leak in the piping system in enclosed spaces andshut down the relevant gas fuel supply.

16.4.3 Routeing of fuel supply pipesFuel piping may pass through or extend into enclosed spacesother than those mentioned in 16.3.1, provided it fulfils oneof the following conditions:

.1 A double wall design with the space between theconcentric pipes pressurised with inert gas at apressure greater than the gas fuel pressure. Theisolating valve, as required by 16.4.5, closesautomatically upon loss of inert gas pressure; or

.2 Installed in a pipe or duct equipped with mechanical exhaust ventilation having a capacityof at least 30 air changes per hour, and shall bearranged to maintain a pressure less than theatmospheric pressure. The mechanical ventilationshall be in accordance with Chapter 12 as applicable. The ventilation shall always be inoperation when there is fuel in the piping and theisolating valve, as required by 16.4.5, shall closeautomatically if the required air flow is not estab-lished and maintained by the exhaust ventilationsystem. The inlet or the duct may be from a non-hazardous machinery space, the ventilation outletshall be in a safe location.





16.4.4 Requirements for fuel gas with pressure greaterthan 1 MPa

16.4.4.1 Fuel delivery lines between the high pressure fuelpumps/compressor and consumers shall be protected with adouble walled piping system capable of containing a highpressure line failure, taking into account the effects of bothpressure and low temperature. A single walled pipe in thecargo area up to the isolating valve(s) required by 16.4.6 isacceptable.

16.4.4.2 The arrangement in 16.4.3.2 may also be accept-able providing the pipe or trunk is capable of containing a highpressure line failure, according to the requirements of 16.4.7and taking into account the effects of both pressure andpossible low temperature and providing both inlet andexhaust of the outer pipe or trunk are in the cargo area.

16.4.5 Gas consumer isolationThe supply piping of each fuel gas consumer unit shall beprovided with fuel gas isolation by automatic double blockand bleed, vented to a safe location, under both normal andemergency operation. The automatic valves shall be arrangedto fail to the closed position on loss of actuating power. In aspace containing multiple consumers, the shutdown of oneshall not affect the fuel gas supply to the others.

16.4.6 Spaces containing gas consumers

16.4.6.1 If the double barrier around the fuel gas supplysystem is not continuous due to air inlets or other openings,or if there is any point where single failure will cause leakageinto the space, it shall be possible to isolate the fuel gassupply to each individual space with an individual master gasfuel valve, which shall be located within the cargo area.It shall operate under the following circumstances:

.1 Automatically by .1.1 Gas detection within the space;.1.2 Leak detection in the annular space of a

double walled pipe;.1.3 Leak detection in other compartments

inside the space, containing single walledgas piping;

.1.4 Loss of ventilation in the annular space ofthe double walled pipe;

.1.5 Loss of ventilation in other compartmentsinside the space, containing single walledgas piping;

.2 Manually from within the space, and at least oneremote location.

The isolation of fuel gas supply to a space, shall not affect thefuel gas supply to other spaces containing gas consumersand shall not cause loss of propulsion or electrical power.

16.4.6.2 If the double barrier around the fuel gas supplysystem is continuous, an individual master valve located inthe cargo area may be provided for each gas consumer insidethe space. The individual master valve shall operate under thefollowing circumstances:

.1 Automatically by: .1.1 Leak detection in the annular space of a

double walled pipe served by that individualmaster valve;

.1.2 Leak detection in other compartmentscontaining single-walled gas piping that ispart of the supply system served by thatindividual master valve;

.1.3 Loss of ventilation or loss of pressure in theannular space of a double walled pipe;

.2 Manually from within the space, and at least oneremote location.

16.4.6.3 It shall be possible to isolate the fuel gas supply toeach individual space containing a gas consumer(s) with anindividual master gas fuel valve, which is located within thecargo area. It shall operate under the following circumstances:

.1 Automatically by: .1.1 Gas detection within the space; .1.2 Leak detection in the annular space of a

double walled space; .1.3 Loss of ventilation in the annular space of

the double walled pipe; .2 Manually from within the space, and at least one

remote location.

16.4.6.4 The isolation of fuel gas supply to a space shall notaffect the gas supply to other spaces containing gasconsumers.

16.4.7 Piping and ducting constructionFuel gas piping in machinery spaces shall comply with 5.1 to5.9 as applicable. The piping shall, as far as practicable, havewelded joints. Those parts of the fuel gas piping that are notenclosed in a ventilated pipe or duct according to 16.4.3, andare on the weather decks outside the cargo area, shall havefull penetration butt-welded joints and shall be fully radio-graphed.

LR 16.4.1 The fuel gas piping in the machinery space isto be tested in place by hydraulic pressure to 7 bar or twicethe working pressure, whichever is the greater. Subsequently,the lines are to be tested by air at the working pressure usingsoapy water, or equivalent, to verify that all joints are abso-lutely tight.

16.4.8 Gas detectionGas detection systems provided in accordance with therequirements of this chapter shall activate the alarm at a relatively low per cent LFL (typically 20 per cent of the LFL inair) and shut down the master fuel gas valve required by16.4.6. at not more than 60 per cent LFL. See also 13.6.15.

16.5 Fuel gas plant and related storage tanks

16.5.1 Provision of fuel gasAll equipment (heaters, compressors, vaporisers, filters, etc.)for conditioning the cargo and/or cargo boil off vapour for itsuse as fuel, and any related storage tanks, shall be located inthe cargo area. If the equipment is in an enclosed space thespace shall be ventilated according to 12.1 and be equippedwith a fixed fire-extinguishing system, according to 11.5, andwith a gas detection system according to 13.6, as applicable.



LLOYD’S REGISTER2


LR 16.5.1 Provision is to be made to enable the machineryand associated pipework used for preparing and supplyingthe gas boil-off to be purged of flammable gas prior to beingopened up for maintenance or survey.

LR 16.5.2 Gas heaters and compressors, of watertightconstruction, may be installed on the open deck providedthey are suitably located and protected from mechanicaldamage.

LR 16.5.3 The prime movers for the gas compressorsare to be regulated to maintain a positive suction pressureand arranged to stop automatically if the pressure on thesuction side of the compressors is lower than 0,035 bargauge or other approved positive pressure appropriate to thecargo tank system.

LR 16.5.4 The suction and discharge connections to thecompressors are to be fitted with isolating valves.

16.5.2 Remote stops

16.5.2.1 All rotating equipment utilised for conditioning thecargo for its use as fuel shall be arranged for manual remotestop from the engine room. Additional remote stops shall belocated in areas that are always easily accessible, typicallycargo control room, navigation bridge where applicable andfire control station.

16.5.2.2 The fuel supply equipment shall be automaticallystopped in the case of low suction pressure or fire detection.The requirements of 18.10.1.1 need not apply to fuel gascompressors or pumps when used to supply gas consumers.

16.5.3 Heating and cooling mediumsIf the heating or cooling medium for the fuel gas conditioningsystem is returned to spaces outside the cargo area, provisions shall be made to detect and alarm the presence ofcargo/cargo vapour in the medium. Any vent outlet shall bein a safe position and fitted with an effective flame screen ofan approved type.

16.5.4 Piping and pressure vesselsPiping or pressure vessels fitted in the fuel gas supply systemshall comply with Chapter 5.

LR 16.5.5 Pressure vessels for storing methane gas areto be of approved design and fitted with pressure relief valvesdischarging to atmosphere in a safe position.

16.6 Special requirements for main boilers

16.6.1 Arrangements

16.6.1.1 Each boiler shall have a separate exhaust uptake.

16.6.1.2 Each boiler shall have a dedicated forced draughtsystem. A crossover between boiler force draught systemsmay be fitted for emergency use providing that any relevantsafety functions are maintained.

16.6.1.3 Combustion chambers and uptakes of boilers shallbe designed to prevent any accumulation of gaseous fuel.

16.6.2 Combustion equipment

16.6.2.1 The burner systems should be of dual type suitableto burn either:• oil fuel.• gas fuel.• oil and gas fuel simultaneously.

16.6.2.2 Burners shall be designed to maintain stablecombustion under all firing conditions.

16.6.2.3 In the event of loss of fuel gas supply an automaticsystem shall be fitted to change over from fuel gas operationto fuel oil operation without interruption of the boiler firing.

16.6.2.4 Gas nozzles and the burner control system shall beconfigured such that fuel gas can only be ignited by an established fuel oil flame, unless the boiler and combustionequipment is designed and approved by LR to light on fuelgas.

LR 16.6.1 Oil fuel alone is to be used for starting up. Itshould be possible to change over easily and quickly from gasto oil fuel operation. These requirements should apply unlessotherwise agreed by the Administration. Each boiler is to havea separate uptake to the top of the funnel or a separatefunnel.

LR 16.6.2 The firing equipment is to be of combined gasand oil type and be capable of burning both fuels simultane-ously. The gas nozzles are to be so disposed as to obtainignition from the oil flame. An interlocking device is to beprovided to prevent the gas fuel supply being opened until theoil and air controls are in the firing position.

16.6.3 Safety

16.6.3.1 There shall be arrangements to ensure that fuel gasflow to the burner is automatically cut off unless satisfactoryignition has been established and maintained.

16.6.3.2 On the pipe of each gas burner a manually operated shut-off valve shall be fitted.

16.6.3.3 Provisions shall be made for automatically purgingthe fuel gas supply piping to the burners, by means of an inertgas, after the extinguishing of these burners.

16.6.3.4 The automatic fuel changeover system required by16.6.2.3 shall be monitored with alarms to ensure continuousavailability.

16.6.3.5 Arrangements shall be made that, in case of flamefailure of all operating burners, the combustion chambers ofthe boilers are automatically purged before relighting.

16.6.3.6 Arrangements shall be made to enable the boilersto be manually purged.

LR 16.6.3 An inert gas or steam purging connection is tobe provided on the burner side of the shut-off arrangementsso that the pipes to the gas nozzles can be purged immedi-ately before and after methane gas is used for firing purposes.





LR 16.6.4 Each burner supply pipe is to be fitted with agas shut-off cock and a flame arrester unless this is incorpo-rated in the burner. An audible alarm is to be provided givingwarning of loss of minimum effective pressure in the oil fueldischarge line or failure of the fuel pump.

LR 16.6.5 In addition to the low water level fuel shutoffand alarm required by Pt 5, Ch 10,15.7 or 16.7 of the Rulesand Regulations for the Classification of Ships (hereinafterreferred to as the Rules for Ships) for oil-fired boilers, similararrangements are to be made for gas shut-off and alarmswhen the boilers are being gas-fired.

LR 16.6.6 A notice board is to be provided at the firingplatform stating:‘If ignition is lost from both oil and gas burners, the combus-tion spaces are to be thoroughly purged of all combustiblegases before relighting the oil burners’.

16.7 Special requirements for gas-fired internalcombustion engines

LR 16.7.1 In addition to the requirements for gas-firedinternal combustion engines outlined in this Chapter, therequirements of Pt 5, Ch 2 are to be complied with.

Dual fuel engines are those that employ fuel gas (with pilot oil)and fuel oil. Oil fuels may include distillate and residual fuels.Gas only engines are those that employ fuel gas only.

16.7.1 Arrangements

16.7.1.1 When fuel gas is supplied in a mixture with airthrough a common manifold, flame arrestors shall be installedbefore each cylinder head.

16.7.1.2 Each engine shall have its own separate exhaust.

16.7.1.3 The exhausts shall be configured to prevent anyaccumulation of unburnt gaseous fuel.

16.7.1.4 Unless designed with the strength to withstand theworst case over pressure due to ignited gas leaks, then airinlet manifolds, scavenge spaces, exhaust system and crankcases shall be fitted with suitable pressure relief systems.Pressure relief systems shall lead to a safe location, away frompersonnel.

16.7.1.5 Each engine shall be fitted with vent systems inde-pendent of other engines for crankcases, sumps and coolingsystems.


16.7.2.1 Prior to admission of fuel gas, correct operation ofthe pilot oil injection system on each unit shall be verified.

16.7.2.2 For a spark ignition engine, if ignition has not beendetected by the engine monitoring system within an enginespecific time after opening of the gas supply valve, this shallbe automatically shut off and the starting sequence terminated. It shall be ensured that any unburned gas mixtureis purged from the exhaust system.

16.7.2.3 For dual fuel engines fitted with a pilot oil injectionsystem an automatic system shall be fitted to change overfrom fuel gas operation to fuel oil operation with minimumfluctuation of the engine power.

16.7.2.4 In the case of unstable operation on engines withthe arrangement in 16.7.2.3 when gas firing, the engine shallautomatically change to fuel oil mode.

16.7.3 Safety

16.7.3.1 During stopping of the engine the gas fuel shall beautomatically shut off before the ignition source.

16.7.3.2 Arrangements shall be provided to ensure thatthere is no unburnt fuel gas in the exhaust gas system prior toignition.

16.7.3.3 Crankcases, sumps, scavenge spaces and coolingsystem vents shall be provided with gas detection. See13.6.15.

16.7.3.4 Provision shall be made within the design of theengine to permit continuous monitoring of possible sourcesof ignition within the crank case. Instrumentation fitted insidethe crankcase shall be in accordance with the requirements ofChapter 10.

16.7.3.5 A means shall be provided to monitor and detectpoor combustion or misfiring that may lead to unburnt gasfuel in the exhaust system during operation. In the event thatit is detected, the gas fuel supply shall be shut down.Instrumentation fitted inside the exhaust system shall be inaccordance with the requirements of Chapter 10.

LR 16.7.4 Additional requirements for gas-fired internal combustion engines and gas turbines

LR 16.7.4.1 Main engines are to be of the dual-fuel typecapable of immediate changeover to oil fuel only. All starting isto be carried out on oil fuel alone.

LR 16.7.4.2 Each cylinder is to be provided with its own individual gas inlet valve admitting gas either to the cylinderor to air inlet port. The timing of this valve is to be such that nogas can pass to the exhaust during the scavenge period norto the inlet port after closure of the air inlet valve.

LR 16.7.4.3 In the event of a fault in the timing mechanismor a cylinder misfire, the exhaust, scavenge and air inlet manifolds are to be protected against the effect of an explo-sion. Where explosion relief valves are fitted they are to relieveto a safe location.



LLOYD’S REGISTER4


LR 16.7.4.4 An isolating valve and flame arrester is to beprovided at the inlet to the gas supply manifold for eachengine. The isolating valve is to be arranged to close auto-matically in the event of low gas pressure, or failure of anycylinder to fire. Arrangements are to be made so that the gassupply to each engine can be shutoff manually from thecontrol position.

LR 16.7.4.5 The crankcase is to be fitted with gas detecting,or equivalent, equipment, and a means for the injection ofinert gas. The inert gas injection is to be capable of remoteoperation from a safe location.Crankcase relief valves are also to be fitted as required by Pt 5, Ch 2,6 of the Rules for Ships.

16.8 Special requirements for gas turbines

LR 16.8.1 In addition to the requirements for gasturbines outlined in this Chapter, the requirements of Pt 5, Ch 3 are to be complied with.

16.8.1 Arrangements

LR 16.8.1.1 Gas turbines are also to comply with LR 16.7.4.

16.8.1.1 Each turbine shall have its own separate exhaust.

16.8.1.2 The exhausts shall be appropriately configured toprevent any accumulation of unburnt gas fuel.

16.8.1.3 Unless designed with the strength to withstand theworst case over pressure due to ignited gas leaks, pressurerelief systems shall be suitably designed and fitted to theexhaust system, taking into consideration of explosions dueto gas leaks. Pressure relief systems within the exhaustuptakes shall be lead to a non-hazardous location, away frompersonnel.


16.8.2.1 An automatic system shall be fitted to change overeasily and quickly from fuel gas operation to fuel oil operationwith minimum fluctuation of the engine power.

16.8.3 Safety

16.8.3.1 Means shall be provided to monitor and detectpoor combustion that may lead to unburnt fuel gas in theexhaust system during operation. In the event that it isdetected, the fuel gas supply shall be shut down.

16.8.3.2 Each turbine shall be fitted with an automatic shut-down device for high exhaust temperatures.

16.9 Alternative fuels and technologies

If acceptable to the Administration, other cargo gases may beused as fuel providing that the same level of safety as naturalgas in this Part is ensured.The use of cargoes identified as toxic by the IGC Code shallnot be permitted.

16.9.1 For cargoes other than LNG, the fuel supply systemshall comply with the requirements of 16.4.1, 16.4.2, 16.4.3and 16.5, as applicable, and shall include means for preventingcondensation of vapour in the system.

16.9.2 Liquefied fuel gas supply systems shall comply with16.4.5.

16.9.3 In addition to the requirements of 16.4.3.2, bothventilation inlet and outlet shall be in a non-hazardous areaexternal to the machinery space.

LR 16.10 Survey

LR 16.10.1 The gas compressors, heaters, pressurevessels and piping are to be constructed under SpecialSurvey, and the installation of the whole plant on board theship unit is to be carried out under the supervision of Lloyd’sRegister’s (LR) Surveyors. On completion, the installation is tobe tested to prove its capability.




Document1 12/04/02 15:23 Page 1

Special Requirements

Section

17.1 General

17.2 Flame screens on vent outlets

17.3 Cargo pumps and discharge arrangements

17.4 Carbon dioxide – High purity

17.5 Carbon dioxide – Reclaimed quality

17.6 Nitrogen

17.1 General

The provisions of this Chapter are applicable where referenceis made in column ‘i' in the Table of Chapter 19.

17.2 Flame screens on vent outlets

When carrying a cargo referenced to this Section, cargo tankvent outlets shall be provided with readily renewable andeffective flame screens or safety heads of an approved type.Due attention shall be paid to the design of flame screens andvent heads, to the possibility of the blockage of these devicesby the freezing of cargo vapour or by icing up in adverseweather conditions. Flame screens shall be removed andreplaced by protection screens in accordance with 8.2.15when carrying cargoes not referenced to this Section.

17.3 Cargo pumps and discharge arrangements

17.3.1 The vapour space of cargo tanks equipped withsubmerged electric motor pumps shall be inerted to a positivepressure prior to loading, during carriage and during unloadingof flammable liquids.

17.3.2 The cargo shall be discharged only by deepwellpumps or by hydraulically operated submerged pumps.These pumps shall be of a type designed to avoid liquid pressure against the shaft gland.

17.3.3 Inert gas displacement may be used for dischargingcargo from Type C independent tanks provided the cargosystem is designed for the expected pressure.

17.4 Carbon dioxide – High purity

17.4.1 Uncontrolled pressure loss from the cargo cancause ‘sublimation’ and the cargo will change from the liquidto the solid state. The precise ‘triple point’ temperature of aparticular carbon dioxide cargo shall be supplied before loadingthe cargo, and will depend on the purity of that cargo, andthis shall be taken into account when cargo instrumentation isadjusted. The set pressure for the alarms and automaticactions described in this Section shall be set to at least 0,05 MPa above the triple point for the specific cargo beingcarried. The ‘triple point’ for pure carbon dioxide occurs at0,05 MPa and –54,4°C.

17.4.2 There is a potential for the cargo to solidify in theevent that a cargo tank relief valve, fitted in accordance with8.2, fails in the open position. To avoid this, a means of isolating the cargo tank safety valves shall be provided andthe requirements of 8.2.9.2 of this Part do not apply whencarrying this carbon dioxide. Discharge piping from safetyrelief valves shall be designed so they remain free fromobstructions that could cause clogging. Protective screensshall not be fitted to the outlets of relief valve discharge pipingso the requirements of 8.2.15 of this Part do not apply.

17.4.3 Discharge piping from safety relief valves are notrequired to comply with 8.2.10, but shall be designed so theyremain free from obstructions that could cause clogging.Protective screens shall not be fitted to the outlets of reliefvalve discharge piping so the requirements of 8.2.15 of thisPart do not apply.

17.4.4 Cargo tanks shall be continuously monitoring forlow pressure when a carbon dioxide cargo is carried. An audible and visual alarm shall be given at the cargo controlposition and on the bridge. If the cargo tank pressure continues to fall to within 0,05 MPa of the ‘triple point’ for theparticular cargo, the monitoring system shall automaticallyclose all cargo manifold liquid and vapour valves and stop allcargo compressors and cargo pumps. The emergency shut-down system required by 18.10 of this Part may be used forthis purpose.

17.4.5 All materials used in cargo tanks and cargo pipingsystem shall be suitable for the lowest temperature that mayoccur in service, which is defined as the saturation temperatureof the carbon dioxide cargo at the set pressure of the automatic safety system described in 17.4.1.

17.4.6 Cargo hold spaces, cargo compressor rooms andother enclosed spaces where carbon dioxide could accumulateshall be fitted with continuous monitoring for carbon dioxidebuild-up. This fixed gas detection system replaces therequirements of 13.6 of this Part, and hold spaces shall bemonitored permanently even if the ship unit has Type C cargocontainment.




Special Requirements

17.5 Carbon dioxide – Reclaimed quality

17.5.1 The requirements of 17.4 also apply to this cargo.In addition, the materials of construction used in the cargosystem shall also take account of the possibility of corrosionin case the reclaimed quality carbon dioxide cargo containsimpurities such as water, sulphur dioxide, etc., which cancause acidic corrosion or other problems.

17.6 Nitrogen

17.6.1 Materials of construction and ancillary equipmentsuch as insulation shall be resistant to the effects of highoxygen concentrations caused by condensation and enrichment at the low temperatures attained in parts of thecargo system. Due consideration shall be given to venitilationin such areas, where condensation might occur, to avoid thestratification of oxygen-enriched atmosphere.



LLOYD’S REGISTER2

Operating Requirements

Section

18.1 General

18.2 Cargo operations manuals

18.3 Cargo information

18.4 Suitability for storage

18.5 Storage of cargo at low temperature

18.6 Cargo transfer operations

18.7 Personnel training

18.8 Entry into enclosed spaces

18.9 Cargo sampling

18.10 Cargo emergency shut-down (ESD) system

18.11 Hot work on or near cargo containment systems

18.12 Additional operating requirements

18.1 General

18.1.1 Those involved in liquefied gas operations are to bemade aware of the special requirements associated with, andprecautions necessary for, their safe operation.

18.2 Cargo operations manuals

18.2.1 The ship unit shall be provided with copies of suit-ably detailed cargo system operating manuals approved bythe Administration such that trained personnel can safelyoperate the unit with due regard to the hazards and propertiesof the cargoes that are permitted to be carried.

18.2.2 The content of the manuals shall include but not belimited to:

.1 Overall operation of the ship unit including proce-dures for cargo tank cool-down and warm-up,cargo transfer, cargo sampling, gas freeing,ballasting, tank cleaning and changing cargoes;

.2 cargo temperature and pressure control systems;

.3 cargo system limitations, including minimumtemperatures (cargo system and inner hull), maxi-mum pressures, cargo transfer rates and fillinglimits;

.4 nitrogen and inert gas systems;

.5 fire-fighting procedures: operation and mainte-nance of fire-fighting systems and use ofextinguishing agents;

.6 special equipment needed for the safe handlingof the particular cargo;

.7 fixed and portable gas detection;

.8 control, alarm and safety systems;

.9 emergency shut-down systems;

.10 procedures to change cargo tank pressure reliefvalve set pressures in accordance with 8.2.8 and4.13.1.3;

.11 emergency procedures, including cargo tankrelief valve isolation, single tank gas-freeing andentry.

18.3 Cargo information

18.3.1 Information shall be on board and available to allconcerned in the form of a cargo information data sheet(s)giving the necessary data for safe cargo operation. Suchinformation shall include, for each product carried:

.1 a full description of the physical and chemicalproperties necessary for safe cargo operationsand containment of the cargo;

.2 reactivity with other cargoes that are capable ofbeing stored.

.3 the actions to be taken in the event of cargo spillsor leaks.

.4 countermeasures against accidental personalcontact.

.5 fire-fighting procedures and fire-fighting media.

.6 special equipment needed for the safe handlingof the particular cargo.

.7 emergency procedures.

18.3.2 The physical data supplied to the Operator, inaccordance with 18.3.1.1, shall include information regardingthe relative cargo density at various temperatures to enablethe calculation of cargo tank filling limits in accordance withthe requirements of Chapter 15.

18.3.3 Contingency plans in accordance with 18.3.1.3, forspillage of cargo carried at ambient temperature, shall takeaccount of potential local temperature reduction such aswhen the escaped cargo has reduced to atmospheric pres-sure and the potential effect of this cooling on hull steel.

18.4 Suitability for storage

18.4.1 The Operator shall ascertain that the quantity andcharacteristics of each product to be loaded are within thelimits indicated in the Loading and Stability Information book-let provided for in 2.2.5.

18.4.2 Care should be taken to avoid dangerous chemicalreactions if cargoes are mixed. This is of particular signifi-cance in respect of:

.1 tank cleaning procedures required betweensuccessive cargoes in the same tank; and

.2 simultaneous storage of cargoes that react whenmixed. This shall be permitted only if thecomplete cargo systems including, but notlimited to, cargo pipework, tanks, vent systemsand refrigeration systems, are separated asdefined in 1.2.44.





18.5 Storage of cargo at low temperature

When carrying cargoes at low temperatures:.1 the cool-down procedure laid down for that

particular tank, piping and ancillary equipmentshall be followed closely.

.2 loading shall be carried out in such a manner asto ensure that design temperature gradients arenot exceeded in any cargo tank, piping or otherancillary equipment.

.3 if provided, the heating arrangements associatedwith the cargo containment systems shall beoperated in such a manner as to ensure that thetemperature of the hull structure does not fallbelow that for which the material is designed.

18.6 Cargo transfer operations

18.6.1 A pre cargo operations meeting shall take placebetween shuttle tanker personnel and the persons responsi-ble at the transfer facility of the ship unit. Informationexchanged shall include the details of the intended cargotransfer operations and emergency procedures. A recognisedindustry checklist shall be completed for the intended cargotransfer and effective communications shall be maintainedthroughout the operation.

18.6.2 Essential cargo handling controls and alarms shallbe checked and tested prior to cargo transfer operations.

18.7 Personnel training

18.7.1 Personnel shall be adequately trained in the opera-tional and safety aspects of the unit. As a minimum:

.1 All personnel shall be adequately trained in theuse of protective equipment provided on boardand have basic training in the procedures, appro-priate to their duties, necessary under emergencyconditions.

.2 Crew shall be trained in emergency proceduresto deal with conditions of leakage, spillage or fireinvolving the cargo and a sufficient number ofthem shall be instructed and trained in essentialfirst aid for the cargoes carried.

18.8 Entry into enclosed spaces

18.8.1 Under normal operational circumstances personnelshall not enter cargo tanks, hold spaces, void spaces, orother enclosed spaces where gas may accumulate, unlessthe gas content of the atmosphere in such space is deter-mined by means of fixed or portable equipment to ensureoxygen sufficiency and the absence of toxic atmosphere.

18.8.2 If it is necessary to gas-free and aerate a holdspace surrounding a Type A cargo tank for routine inspection,and the cargo tank is carrying flammable cargo, the inspec-tion shall be conducted when the tank contains only theminimum amount of cargo ‘heel’ to keep the cargo tank cold.The hold shall be re-inerted as soon as the inspection iscompleted.

18.8.3 Personnel entering any space designated as ahazardous area on a ship unit carrying flammable productsshall not introduce any potential source of ignition into thespace unless it has been certified gas free and is maintainedin that condition. Portable gas detection equipment must beutilised at all times to ensure personnel safety.

18.9 Cargo sampling

18.9.1 Any cargo sampling shall be conducted under thesupervision of an Officer who shall ensure that protectiveclothing appropriate to the hazards of the cargo is used byeveryone involved in the operation.

18.9.2 When taking liquid cargo samples the Officer shallensure that the sampling equipment is suitable for thetemperatures and pressures involved, including cargo pumpdischarge pressure if relevant.

18.9.3 The Officer shall ensure that any cargo sampleequipment used is connected properly to avoid any cargoleakage.

18.9.4 After sampling operations are completed, theOfficer shall ensure that any sample valves used are closedproperly and the connections used are correctly blanked.

18.10 Cargo emergency shut-down (ESD) system

18.10.1 General

18.10.1.1 A cargo emergency shut-down system shallbe fitted to all ship units to stop cargo flow in the event of anemergency, either internally within the ship unit, or duringcargo transfer with shuttle tankers. The design of the ESDsystem shall avoid the potential generation of surge pressureswithin cargo transfer pipe work, see 18.10.2.1.4.

18.10.1.2 Auxiliary systems for conditioning the cargothat use toxic or flammable liquids or vapours shall be treatedas cargo systems for the purposes of ESD. Indirect refrigera-tion systems using an inert medium, such as nitrogen, neednot be included in the ESD function.

18.10.1.3 The ESD system shall be activated by themanual and automatic inputs listed in Table 18.1. Any addi-tional inputs should only be included in the ESD system if itcan be shown their inclusion does not reduce the integrity andreliability of the system overall.

18.10.1.4 The ESD systems of the ship unit shall incor-porate a shuttle tanker-ship unit link in accordance with ISO28460:2010 Petroleum and natural gas industries –Installation and equipment for liquefied natural gas - Ship-to-shore interface and port operations or an equivalentrecognised Standard.

18.10.1.5 A functional flow chart of the ESD systemand related systems shall be provided in the cargo controlstation.



LLOYD’S REGISTER2


18.10.2 ESD valve requirements

18.10.2.1 General

18.10.2.1.1 The term ESD valve means any valve oper-ated by the ESD system.

18.10.2.1.2 ESD valves shall be remotely operated, be ofthe fail closed type (closed on loss of actuating power), shallbe capable of local manual closure and have positive indica-tion of the actual valve position. As an alternative to the localmanual closing of the ESD valve, a manually operated shut-offvalve in series with the ESD valve shall be permitted. Themanual valve shall be located adjacent to the ESD valve.Provisions shall be made to handle trapped liquid should theESD valve close while the manual valve is also closed. A manually operated vent valve in the pneumatic/hydrauliclogic is preferable to an additional in-line valve.




Pumps Compressor Systems Valves Link

Shut-down action →

Initiation ↓

Cargopumps/cargoboosterpumps

Spray/strippingpumps

Vapour returncompressors

Fuel gascompressorsand system

Reliquefactionplant****, includingcondensatereturn pumps,if fitted

Gas combustionunit

ESD valves Signal to shipunit-shuttletanker link*****

Emergency pushbuttons(see 18.10.1.3)

Fire detection ondeck or in compressor house*

High level in cargotank***

Signal from shipunit-shuttle tankerlink

Loss of motivepower to ESDvalves**

Main electric powerfailure (‘blackout’)

Note 5

Note 5

Note 5

Note 2

Note 2

Note 1Note 2

Note 2

Note 2

Note 5

Note 1

Note 3

n/a

Note 5

Note 1

n/a

n/a

Note 5

Note 4

n/a

NOTES1. These items of equipment can be omitted from these specific automatic shut-down initiators provided the compressor inlets are

protected against cargo liquid ingress.2. If the fuel gas compressor is used to return cargo vapour to the ship unit, it shall be included in the ESD system only when operating in

this mode.3. If the reliquefaction plant compressors are used for vapour return/ship unit line clearing, they shall be included in the ESD system only

when operating in that mode.4. Alternatively, a stage 1 high level in an individual cargo tank may initiate the closure of the shut-off valve referred to in 13.3.2, and not

the ESD valve referred to in 18.10.2.1.3. The sensor indicated in 13.3.2 shall also ensure that when all tank valves referred to in 13.3.2are shut that the ESD in 18.10.1.3 is operated.

5. These items of equipment shall not be started automatically upon recovery of main electric power and without confirmation of safe conditions.

Remarks* Fusible plugs, electronic point temperature monitoring or area fire detection may be used for this purpose on deck.** Failure of hydraulic, electric or pneumatic power for remotely operated ESD valve actuators.*** See 13.3.2 and 13.3.3.**** Indirect refrigeration systems using an inert medium, such as nitrogen, need not be included in the ESD function.***** Signal need not indicate the event initiating ESD. Functional requirement.n/a Not applicable.

Table 18.1 ESD Functional Arrangements


18.10.2.1.3 ESD valves in liquid piping systems shallclose fully and smoothly within 30 seconds of actuation.Information about the closure time of the valves and theiroperating characteristics shall be available on board, and theclosing time shall be verifiable and repeatable.

18.10.2.1.4 The closing time of the valve referred to in13.3.1 to 13.3.3 (i.e., time from shut-down signal initiation tocomplete valve closure) shall not be greater than:

whereU = ullage volume at operating signal level (m3)

LR = maximum loading rate agreed between ship unitand shuttle tanker (m3/h).

The loading rate shall be adjusted to limit surge pressure onvalve closure to an acceptable level, taking into account theloading hose or arm and the piping systems of the ship unitand shuttle tanker where relevant.

18.10.2.2 Ship unit-shuttle tanker manifold connectionsOne ESD valve shall be provided at each manifold connec-tion. Cargo manifold connections not being used for transferoperations shall be blanked with blank flanges rated for thedesign pressure of the pipeline system.

18.10.2.3 Cargo system valvesIf cargo system valves as defined in 5.5 are also ESD valveswithin the meaning of 18.10, then the requirements of 18.10will apply.

18.10.3 ESD system controls

18.10.3.1 As a minimum, the ESD system shall be capableof manual operation by a single control in the control positionrequired by 13.1.2 or the cargo control room if installed, andno less than two locations in the cargo area.

18.10.3.2 The ESD shall be automatically activated ondetection of a fire on the weather decks of the cargo areaand/or cargo machinery spaces. As a minimum, the methodof detection used on the weather decks should cover theliquid and vapour domes of the cargo tanks, the cargo mani-folds and areas where liquid piping is dismantled regularly.Detection may be by means of fusible elements designed tomelt at temperatures between 98°C and 104°C, or by areafire detection methods.

18.10.3.3 Cargo machinery that is running shall bestopped by activation of the ESD system in accordance withthe cause and effect matrix in Table 18.1.

18.10.4 Additional shut-downs

18.10.4.1 The requirements of 8.3.1.1 to protect thecargo tank from external differential pressure may be fulfilledby using an independent low pressure trip to activate the ESDsystem, or as a minimum to stop any cargo pumps orcompressors.

3600ULR

18.10.4.2 An input to the ESD system from the over-flow control system required by 13.3 may be provided to stopany cargo pumps or compressors running at the time a highlevel is detected, as this alarm may be due to inadvertentinternal transfer of cargo from tank to tank.

18.10.5 Pre-operations testingCargo emergency shut-down and alarm systems involved incargo transfer shall be checked and tested before cargohandling operations begin.

18.11 Hot work on or near cargo containmentsystems

18.11.1 Special fire precautions shall be taken in the vicin-ity of cargo tanks and particularly insulation systems that maybe flammable or contaminated with hydrocarbons or that maygive off toxic fumes as a product of combustion.

18.12 Additional operating requirements

Additional operating requirements will be found in the follow-ing paragraphs of this Part 2.2.2, 2.2.5, 2.2.6, 3.8.3, 3.8.4,5.3.2, 5.3.3.3, 5.7.3, 7.1, 8.2.7, 8.2.8, 8.2.9, 9.2, 9.3, 9.4.4,12.1.1, 13.1.3, 13.3.5, 13.6.16, 14.3.3, 15.3, 15.6, 16.6.3.



LLOYD’S REGISTER4

Summary of Minimum Requirements

Section

19.1 Explanatory notes to the summary of minimumrequirements




Product name(column a)

UN Number(column b)

Ship type(column c)

Ship unit type 2G, see Chapter 2

Independent tank type C required(column d)

- not required under the IGC Code

Tank environmental control(column e)

- no special requirements under the IGC Code

Vapour detection(column f)

F: Flammable vapour detectionA: Asphixiant

Gauging(column g)

R: Indirect, closed or restricted, see Chapter 13C: indirect or closed, see Chapter 13

MFAG Table no.(column h)

MFAG numbers are provided for information on the emergency procedures to be applied in the event ofan accident involving the products covered by the IGC CodeWhere any of the products listed are carried at low temperature from which frostbite may occur, MFAG no. 620 is also applicable

Special requirements(column i)

When specific reference is made to Chapter 17, these requirements shall be additional to the requirements in any other column

19.1 Explanatory notes to the summary of minimum requirements

Summary of Minimum RequirementsRULES AND REGULATIONS FOR THE CLASSIFICATION OF A FLOATING OFFSHORE INSTALLATION AT A FIXED LOCATION, June 2013


LLOYD’S REGISTER2

Product nameU

N n

umbe

r

Shi

p un

itty

pe

Inde

pend

ent t

ank

type

Cre

quire

d

Con

trol

of v

apou

r sp

ace

with

in c

argo

tank

s

Vapo

ur d

etec

tion

Gau

ging

MFA

G T

able

no.

Spe

cial

requ

irem

ents

Butane 1011 2G - - F R 310 -

Butane-propanemixture 1011/1978 2G - - F R 310 -

Carbon dioxide(High Purity) - 2G

see Note 1 - - A R - 17.4

Carbon dioxide(Reclaimed Quality) - 2G

see Note 1 - - A R - 17.5

Ethane 1961 2G - - F R 310 -

Methane (LNG) 1972 2G - - F C 620 -

Nitrogen 2040 2Gsee Note 1 - - A C - 17.6

Pentane(all isomers)see Note 2

1265 2G - - F R 310 17.2, 17.3

Propane 1978 2G - - F R 310 -

LR NOTES1. Ship units designed to store LNG or LPG with additional tanks to store carbon dioxide are to comply with the requirements for ship unit

type 2G.2. This cargo is also covered by the International Code for the Construction and Equipment of Ships Carrying Dangerous Chemicals in Bulk

(IBC Code).

b c d e f g h ia

Non-Metallic Materials

Section

1 General

2 Material selection criteria

3 Properties of materials

4 Material selection and testing requirements

5 Quality control and quality assurance (QA/QC)

6 Bonding and joining process requirement andtesting

7 Production bonding tests and controls

1 General

The guidance given in this Appendix is in addition to therequirements of 4.19 where applicable to non-metallic materials.The manufacture, testing, inspection and documentation ofnon-metallic materials shall in general comply with recognisedStandards, and with the specific requirements of this Part asapplicable.When selecting a non-metallic material, the designer mustensure it has properties appropriate to the analysis and spec-ification of the system requirements. A material can beselected to fulfil one or more requirements.A wide range of non-metallic materials may be considered.Therefore the section below on material selection criteriacannot cover every eventuality and must be considered asguidance.

2 Material selection criteria

Non-metallic materials may be selected for use in variousparts of liquefied gas carrier cargo systems based on consid-eration of the following basic properties:Insulation – the ability to limit heat flowLoad bearing – the ability to contribute to the strength of thecontainment systemTightness – the ability to provide liquid and vapour tight barri-ersJoining – the ability to be joined (for example by bonding,welding or fastening).Additional considerations may apply, depending on thespecific system design.

3 Properties of materials

3.1 Flexibility of insulating materialThe ability of an insulating material to be bent or shaped easilywithout damage or breakage.

3.2 Loose fill materialA homogeneous solid, generally in the form of fine particles,such as a powder or beads, normally used to fill the voids inan inaccessible space to provide an effective insulation.

3.3 Nanomaterial A material with properties derived from its specific micro-scopic structure.

3.4 Cellular materialA material type containing cells that are either open, closedor both and which are dispersed throughout its mass.

3.5 Adhesive materialA product that joins or bonds two adjacent surfaces togetherby an adhesive process.

3.6 Other materialsMaterials that are not characterised in this section of the Partshall be identified and listed. The relevant tests used to eval-uate the suitability of material for use in the cargo system shallbe identified and documented.

4 Material selection and testing requirements

4.1 Material specification When the initial selection of a material has been made, testsare to be conducted to validate the suitability of this materialfor the use intended.The material used shall clearly be identified and the relevanttests shall be fully documented.Materials shall be selected according to their intended use.They shall:• be compatible with all the products that may be carried• not be contaminated by any cargo nor react with it• not have any characteristics or properties affected by the

cargo and • be capable to withstand thermal shocks within the oper-

ating temperature range.

4.2 Material testingThe tests required for a particular material depend on thedesign analysis, specification and intended duty. The list oftests below is for illustration. Any additional tests required, forexample in respect of sliding, damping and galvanic insula-tion, shall be identified clearly and documented.Materials selected according to 4.1 of this Appendix shall betested further according to Table A1.4.1.Thermal shock testing should submit the material and/orassembly to the most extreme thermal gradient it will experi-ence when in service.


Part 11, Appendix 1Sections 1 to 4


Mechanical tests X X

Tightness tests X

Thermal tests X

Physical tests(see 6.9.2.5)

Table A1.4.1 Material testing


4.2.1 Inherent properties of materialsTests shall be carried out to ensure that the inherent proper-ties of the material selected will not have any negative impactin respect of the use intended.For all selected materials, the following properties shall beevaluated:• Density; example Standard ISO 845• Linear coefficient of thermal expansion (LCTE); example

Standard ISO 11359 across the widest specified oper-ating temperature range. However, for loose fill material,the volumetric coefficient of thermal expansion (VCTE)shall be evaluated as this is more relevant.

Irrespective of their inherent properties and intended duty, allmaterials selected shall be tested for the design servicetemperature range down to 5°C below the minimum designtemperature, but not lower than –196°C.Each property evaluation test shall be performed in accor-dance with recognised Standards. Where there are no suchstandards, the test procedure proposed shall be fully detailedand submitted to the Administration for acceptance.Sampling shall be sufficient to ensure a true representation ofthe properties of the material selected.

4.2.2 Mechanical testsThe mechanical tests shall be performed in accordance withTable A1.4.2.

If the chosen function for a material relies on particular prop-erties such as tensile, compressive and shear strength, yieldstress, modulus or elongation, these properties shall betested to a recognised Standard. If the properties required areassessed by numerical simulation according to a high orderbehaviour law, the testing shall be performed to the satisfac-tion of the Administration.Creep may be caused by sustained loads, for example cargopressure or structural loads. Creep testing shall be conductedbased on the loads expected to be encountered during thedesign life of the containment system.

4.2.3 Tightness testsThe tightness requirement for the material shall relate to itsoperational functionality. Tightness tests shall be conducted to give a measurement ofthe material’s permeability in the configuration correspondingto the application envisaged (e.g., thickness and stress condi-tions) using the fluid to be retained (e.g., cargo, water vapouror trace gas). The tightness tests shall be based on the tests indicated asexamples in Table A1.4.3.

4.2.4 Thermal conductivity testsThermal conductivity tests shall be representative of the life-cycle of the insulation material so its properties over thedesign life of the cargo system can be assessed. If theseproperties are likely to deteriorate over time, the material shallbe aged as best as possible in an environment correspondingto its lifecycle, for example, operating temperature, light,vapour and installation (e.g., packaging, bags, boxes, etc).Requirements for the absolute value and acceptable range ofthermal conductivity and heat capacity shall be chosen takinginto account the effect on the operational efficiency of thecargo containment system. Particular attention should alsobe paid to the sizing of the associated cargo handling systemand components such as safety relief valves plus vapourreturn and handling equipment.Thermal tests shall be based on the tests indicated as exam-ples in Table A1.4.4 or their equivalents.

4.2.5 Physical testsIn addition to the requirements of 4.19.2.3 and 4.19.3.2,Table A1.4.5 provides guidance and information on some ofthe additional physical tests that may be considered.


Part 11, Appendix 1Section 4

LLOYD’S REGISTER2

Mechanical tests Load bearing structural

Tensile ISO 527ISO 1421ISO 3346ISO 1926

Shearing ISO 4587ISO 3347ISO 1922ISO 6237

Compressive ISO 604ISO 844ISO 3132

Bending ISO 3133ISO 14679

Creep ISO 7850

Tightness tests Tightness

Porosity/Permeability ISO 15106ISO 2528ISO 2782

Thermal tests Insulting

Thermal conductivity ISO 8301ISO 8302

Heat capacity x

Table A1.4.2 Mechanical tests

Table A1.4.3 Tightness tests

Table A1.4.4 Thermal conductivity tests


Requirements for loose fill material segregation shall be chosenconsidering its potential adverse effect on the material properties (density, thermal conductivity) when subjected toenvironmental variations such as thermal cycling and vibration.Requirements for a materials with closed cell structures shallbe based on its eventual impact on gas flow and bufferingcapacity during transient thermal phases.Similarly, adsorption and absorption requirements shall takeinto account the potential adverse effect an uncontrolledbuffering of liquid or gas may have on the system.

5 Quality control and quality assurance (QA/QC)

5.1 GeneralOnce a material has been selected, after testing as outlined inSection 4 of this Appendix, a detailed quality assur-ance/quality control (QA/QC) programme shall be applied toensure the continued conformity of the material during instal-lation and service. This programme shall consider the materialstarting from the manufacturer’s quality manual (QM) and thenfollow it throughout the construction of the cargo system.The QA/QC programme shall include the procedure for fabri-cation, storage, handling and preventive actions to guardagainst exposure of a material to harmful effects. These mayinclude, for example, the effect of sunlight on some insulationmaterials or the contamination of material surfaces by contactwith personal products such as hand creams.

LR A1.5.1 The proposed procedure is to be submitted toLR for consideration. All other materials in the containmentsystem are also to be considered and included in theaforementioned procedure.

The sampling methods and the frequency of testing in theQA/QC programme shall be specified to ensure the contin-ued conformity of the material selected throughout itsproduction and installation.Where powder or granulated insulation is produced, arrange-ments should be made to prevent compacting of the materialdue to vibrations.

5.2 QA/QC during component manufactureThe QA/QC program in respect of component manufacturemust include, as a minimum but not limited to, the followingitems:

5.2.1 Component identificationFor each material, the manufacturer shall implement a mark-ing system to clearly identify the production batch. Themarking system shall not interfere in any way with the prop-erties of the product.This marking system shall ensure complete traceability of thecomponent and shall include:• Date of production and potential expiration date• Manufacturer’s references• Reference specification• Reference order• When necessary, any potential environmental parame-

ters to be maintained during transportation and storage.

5.2.2 Production sampling and audit methodRegular sampling is required during production to ensure thequality level and continued conformity of a selected material. The frequency, the method and the tests to be performedshall be defined in QA/QC program; for example, these testswill usually cover, inter alia, raw materials, process parame-ters and component checks.Process parameters and results of the production QC testsshall be in strict accordance with those detailed in the QM forthe material selected.The objective of the audit method as described in the QM isto control the repeatability of the process and the efficacy ofthe QA/QC program.During auditing, Auditors shall be provided with free accessto all production and QC areas. Audit results must be inaccordance with the values and tolerances as stated in therelevant QM.


Part 11, Appendix 1Sections 4 & 5


Physical tests Flexible insulating Loose fill Nanomaterial Cellular Adhesive

Particle size x

Closed cells content ISO 4590

Absorption/desorption ISO 12571 x ISO 2896

Absorption/desorption x

Viscosity ISO 2555ISO 2431

Open time ISO 10364

Thixotropic properties x

Hardness ISO 868

Table A1.4.5 Physical tests


6 Bonding and joining process requirement andtesting

6.1 Bonding procedure qualification The Bonding Procedure Specification and Qualification Testshould be defined in accordance with an appropriate recog-nised Standard.The bonding procedures shall be fully documented beforework commences to ensure the properties of the bond areacceptable.The following parameters are to be considered when devel-oping a specification:• surface preparation• materials storage and handling prior to installation• covering time• open time• mixing ratio, deposited quantity• environmental parameters (temperature, humidity)• curing pressure, temperature and time.Additional requirements are to be included if necessary toensure acceptable results.The bonding procedures specification shall be validated byan appropriate procedure qualification testing programme.

6.2 Personnel qualificationsPersonnel involved in bonding processes shall be trained andqualified to recognised Standards.Regular tests shall be made to ensure the continued perfor-mance of people carrying out bonding operations to ensure aconsistent quality of bonding.

7 Production bonding tests and controls

7.1 Destructive testingDuring production, representative samples shall be taken andtested to check they correspond to the required level ofstrength as required for the design.

7.2 Non-destructive testingDuring production, tests which are not detrimental to bondintegrity shall be performed using an appropriate techniquesuch as:• visual examination • internal defects detection (for example acoustic, ultra-

sonic or shear test• local tightness testing. If the bonds have to provide tightness as part of their designfunction, a global tightness test of the cargo containmentsystem shall be completed after the end of the erection inaccordance with the designer’s and QA/QC programme.The QA/QC standards shall include acceptance standards forthe tightness of the bonded components when built andduring the lifecycle of the containment system.


Part 11, Appendix 1Sections 6 & 7

LLOYD’S REGISTER4

Document1 12/04/02 15:23 Page 1

© Lloyd’s Register Group Limited 2013Published by Lloyd’s Register

Registered office71 Fenchurch Street, London, EC3M 4BS

United Kingdom

rules and regulations classification of a floating offshore installation at...

Documents