hvac specs woodside

CONTROLLED DOCUMENT Title: Standard: Heating, Ventilation and Air

Conditioning (HVAC)

Controlled Ref No: W1000SM3132376 Revision: 2

Name Date

Prepared by: Gordon Fisher 4 / 1 2 / 0 8

Approved by: Michael Hamblin 1 4 / 1 2 / 0 8

Custodian: Godfrey Howard 5 / 1 2 / 0 8

Concurrence (Agreement that must be obtained if an item is prepared external to, but impacts, a department or division. If concurrence is required, it must be noted within the body of the item).

1.

Woodside Management System Sub-processes MUST obtain concurrence endorsement from BopCom. The date of the BopCom meeting where endorsement is granted should be indicated below.

BopCom Endorsement Meeting date when endorsement granted:

REVISION HISTORY

Revision Description Date Prepared by Approved by

0 Merged A3000MM012 and A3000SM045 03/2007 D Gomes M Hackett

1 Updated as per WELEV08030220 11/2008 G Fisher M Hamblin

2 Listed WEL Standards 11/2008 G Fisher M Hamblin

3

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Unclassified (Shared without Restrictions) Review on/by

(01/03/2010) By WEL

Restricted (Freely Shared within Woodside and Associated Companies)

Review Not Required For WEL Under PO/Contract No:

Confidential (Shared With Selected Personnel)

Most Confidential (Strict Need-to-Know Basis)

This document is protected by copyright. No part of this document may be reproduced, adapted, transmitted, or stored in any form by any process (electronic or otherwise) without the specific written consent of Woodside. All rights are reserved.

Controlled Ref No: W1000SM3132376 Revision: 2 Native file DRIMS No: 3132376 of 93

Uncontrolled when printed. Refer to electronic version for most up to date information.

Title: Standard: Heating, Ventilation and Air Conditioning (HVAC)




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PREFACE Woodside Energy Ltd. (WEL) has developed a suite of Engineering and Technical Standards and Guidelines. It is intended that these reflect the most suitable engineering practices for use on all new WEL facilities as well as the modification of existing facilities. The application of the Standards is mandatory. The application of Guidelines is to support the implementation of the Standards, and are considered best practice, but are not mandatory. The Standards are based on the experience acquired by WEL personnel and contractors during WEL’s involvement with the design, construction, operation and maintenance of WEL processing units and facilities. Where appropriate, the Standards are based on or make reference to national and international standards and codes of practice. The objective of this publication is to ensure the overall integrity of engineering design and to achieve maximum technical and economic benefits through the standardisation of engineering and technical practices. The use by WEL contractors or manufacturers/suppliers of the Engineering and Technical Standards contained in this publication does not relieve them of any responsibility whatsoever for the quality of design, materials and workmanship that they have been engaged to provide. Where the standards to be used for a certain application are not provided for in this publication, WEL expects that the standards that are used will achieve the same level of integrity as reflected in this publication. If WEL contractors or manufacturers/suppliers have any doubt as to the relevant standard to use, then they must consult WEL, however they will remain responsible at all times for the use of the most appropriate standard. Specific requirements may be added as an addendum to these Standards and Guidelines for various projects. Project specific requirements must not depart from the requirements of the Engineering and Technical Standards contained in this publication. Where changes or additions to these Standards are required, they must be raised as a deviation and presented to the WEL Technical Authority for consideration. WEL grants the right to use these Standards and Guidelines to WEL’s consultants, contractors and suppliers who are contractually authorised to do so and to any tier of contractor to its consultants, contractors and suppliers who are contractually required to comply with them. DISCLAIMER WEL and its joint venture partners disclaim any liability of whatsoever nature for any damage (including injury or death) suffered by any company or person whomsoever as a result of or in connection with the use, application or implementation of any standard, combination of standards or any part thereof contained in this publication.





TABLE OF CONTENTS

1 INTRODUCTION ................................................................................ 6 1.1 PURPOSE ................................................................................................... 6 1.2 SUPPOSITION ............................................................................................ 6 1.3 COMPLIANCE............................................................................................. 6 1.4 HVAC FUNCTION ....................................................................................... 7 1.5 DEFINITIONS .............................................................................................. 7

1.5.1 General Definitions....................................................................................... 7 1.5.2 Specific Definitions....................................................................................... 8

1.6 ABBREVIATIONS ....................................................................................... 9

2 PRIMARY GUIDANCE..................................................................... 10 2.1 FORMATIVE CONSIDERATIONS............................................................. 10 2.2 HAZARDOUS AREA CLASSIFICATION.................................................. 10

2.2.1 HVAC Role for Hazardous Area Enclosures.............................................. 11 2.2.2 Minimum Ventilation Rate .......................................................................... 11 2.2.3 Non-hazardous Areas ................................................................................ 12 2.2.4 Hazardous Classifications.......................................................................... 12 2.2.5 Equipment Protection Techniques ............................................................. 12

2.3 ENVIRONMENTAL CONDITIONS ............................................................ 13 2.3.1 External Meteorological Conditions............................................................ 14 2.3.2 Internal Space Conditions .......................................................................... 15

3 BASIS OF DESIGN.......................................................................... 18 3.1 FACILITY LAYOUT ................................................................................... 18

3.1.1 Temporary Refuge ..................................................................................... 18 3.1.2 Equipment Location ................................................................................... 19 3.1.3 General Arrangements............................................................................... 19 3.1.4 HVAC Fresh-Air Intakes and Exhausts ...................................................... 20

3.2 TYPEs OF HVAC SYSTEM....................................................................... 21 3.2.1 Mechanical Ventilation ............................................................................... 22 3.2.2 Heating....................................................................................................... 23 3.2.3 Cooling ....................................................................................................... 23 3.2.3.1 Room Air Conditioners ............................................................................ 23 3.2.3.2 Packaged Air Conditioning Units............................................................. 24 3.2.3.3 Central AHU with Refrigeration Plant ...................................................... 24 3.2.4 Floating Production Vessels....................................................................... 25

3.3 CONTROLS PHILOSOPHY ...................................................................... 25 3.3.1 Control and Monitoring - Normal Operation ............................................... 27 3.3.1.1 Integrated HVAC Panels ......................................................................... 27 3.3.1.2 Dedicated HVAC Panels ......................................................................... 27 3.3.1.3 Fan Control.............................................................................................. 29 3.3.1.4 Fire Damper Control................................................................................ 29 3.3.1.5 Loss of Pressurization ............................................................................. 30


is document is protected by copyright. No part of this document may be reproduced, adapted, transmitted, or stored in any m by any process (electronic or otherwise) without the specific written consent of Woodside. All rights are reserved.

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3.3.1.6 Temperature Control ............................................................................... 30 3.3.2 Control and Monitoring - Emergency Conditions ....................................... 30

3.4 SPARING PHILOSOPHY .......................................................................... 31 3.5 MAINTENANCE PHILOSOPHY ................................................................ 33

3.5.1 Spares........................................................................................................ 34 3.6 MATERIALS AND CORROSION .............................................................. 35 3.7 DESIGN CALCULATIONS ........................................................................ 36

4 SYSTEM DESIGN - AREA SPECIFIC ............................................. 38 4.1 PROCESS AND UTILITIES AREAS ......................................................... 38

4.1.1 Hazardous Area Enclosures ...................................................................... 38 4.1.2 Non-Hazardous Areas................................................................................ 38

4.2 LIVING QUARTERS.................................................................................. 39 4.3 DRILLING AND DRILLING UTILITIES AREAS ........................................ 43

4.3.1 Shale Shakers & Cuttings Cleaning Units.................................................. 43 4.3.2 Mud Tanks ................................................................................................. 43 4.3.3 Air Scrubbers ............................................................................................. 44 4.3.4 Cement Units ............................................................................................. 45

4.4 GAS TURBINE ENCLOSURES ................................................................ 45 4.5 EMERGENCY VENTILATION ................................................................... 45 4.6 ANCILLIARY AREAS................................................................................ 46

4.6.1 Battery and Charger Rooms ...................................................................... 46 4.6.2 Laboratories ............................................................................................... 46 4.6.3 Chemical Storage Rooms .......................................................................... 47 4.6.4 Purging Equipment..................................................................................... 47

5 INSTALLATION, COMMISSIONING AND DOCUMENTATION...... 47

6 REFERENCES ................................................................................. 48

7 APPENDICES .................................................................................. 51 7.1 APPENDIX 1 Air Handling Units.............................................................. 52 7.2 APPENDIX 2 Constant Volume Terminal Reheat Units......................... 56 7.3 APPENDIX 3 Cooling Plant...................................................................... 59 7.4 APPENDIX 4 Cowls and Weather Louvres............................................. 65 7.5 APPENDIX 5 Ductwork ............................................................................ 66 7.6 APPENDIX 6 Fans .................................................................................... 69 7.7 APPENDIX 7 Filters and Coalescers....................................................... 72 7.8 APPENDIX 8 Fire Dampers...................................................................... 74 7.9 APPENDIX 9 General Dampers ............................................................... 77 7.10 APPENDIX 10 Grilles and Diffusers........................................................ 80 7.11 APPENDIX 11 Heater Banks.................................................................... 83 7.12 APPENDIX 12 Humidifiers ....................................................................... 86 7.13 APPENDIX 13 Pumps............................................................................... 88 7.14 APPENDIX 14 Sound Attenuators........................................................... 90

1





INTRODUCTION

1.1 PURPOSE The purpose of this code is to identify the minimum engineering standards and requirements acceptable to WEL, for the basis of design, detail design, type of equipment and fabrication associated with mechanical HVAC systems. The code was initially developed for offshore facilities however it is equally applicable to onshore installations. This code should be applied to new installations and the upgrade and modification of existing facilities. It is directed at system designers, equipment/requisitioning engineers or other engineers responsible for the design, engineering and operation of WEL installations. The code may be used by WEL directly or by Agents, Consultants or Contractors acting on behalf of WEL. Any intent to use an alternative code of practice for HVAC systems, or to deviate from the intent of this document shall be agreed with the WEL custodian. Compliance with the requirements of this code of practice does not alleviate the user of the responsibility to follow safe and good engineering practice throughout.

1.2 SUPPOSITION It is assumed that a full evaluation has verified a need for the development of a mechanical HVAC system or multiple systems, essential for the effective operation of the facility under review or design.

Areas and spaces identified with a requirement for mechanical HVAC are also assumed to be of a fully enclosed construction. Enclosed areas spaces can be of the normally manned or unmanned and located in either a hazardous area or non-hazardous area.

Areas that may be suitable for natural ventilation (dependent on natural wind effects and air temperature differentials) are not covered by this code.

1.3 COMPLIANCE Primarily the Standard is intended for new projects and shall provide a guide for the project design team, consultants and contractors to ensure HVAC conformity during the design phases of the project.

Additionally the Standard shall also be used as a guide for the review of existing facilities. However it is recognised that practical constraints may be found when applied to existing facilities. In such cases, and prior to an upgrade proposal, a full evaluation of the existing HVAC system including the existing hazards, controls, and limitations shall be conducted. Thereafter the HVAC upgrade proposal shall include a summary of the upgrade benefits, associated costs and also clearly indicate any deviations from this code.





Deviations from the code requirements shall be presented to the WEL custodian for consideration.

1.4 HVAC FUNCTION HVAC systems provide vital safety functions, a habitable environment for personnel and appropriate conditions for effective equipment operation. The core requirements of a HVAC system are to provide one or more of the following functions:

• Prevent by means of pressurisation, the ingress of smoke or flammable gas/air mixtures into enclosed non-hazardous spaces – when they are located in the vicinity of hazardous areas

• Prevent the concentration of flammable gas/air mixtures by means of adequate ventilation, to ensure the dilution, dispersion and removal of such mixtures

• Operate during an emergency where serving enclosed spaces containing personnel and/or essential electrical or mechanical systems – when the main power source is unavailable

• Provide a controlled internal environment in which personnel, plant and systems can operate effectively

1.5 DEFINITIONS 1.5.1 General Definitions

The definitions below shall be included if the words defined are used in the Code of Practice.

• The Contractor is the party that carries out all or part of the design, engineering, procurement, construction, commissioning or management of a project, or operation or maintenance of a facility. The Principal may undertake all or part of the duties of the Contractor.

• The Manufacturer/Supplier is the party that manufactures or supplies equipment and services to perform the duties specified by the Contractor.

• The Principal is the party that initiates the project and ultimately pays for its design and construction. The Principal will generally specify the technical requirements. The Principal may also include an agent or consultant authorised to act for, and on behalf of, the Principal.

• The words shall/must/will indicate a mandatory requirement.

• The word should indicates a recommended course of action.

• The words may/can indicate one acceptable course of action.

• WEL Technical Integrity Custodian (TIC) in this document refers to Operations Technical Support Manager. Authority to deviate from the standards is delegated to the custodian(s) indicated on the document details page of this document.





1.5.2 Specific Definitions

Axial Flow Fan A fan in which the air enters the impeller axially and is discharged axially

Airflow Rate The volumetric flow rate derived from the mass flow rate at a standard air density of 1.2 kg/m³

Air Handling Unit (AHU)

A purpose built unit for the delivery of supply-air via associated ductwork distribution networks

Azeotropic A mixture of two or more liquids having a boiling point independent of the individual liquid boiling points

Continuous Running Any equipment or plant operating 24 hours per day, 365 days per year

Cross Contamination Pollution of any HVAC air intake by induction of contaminated air from exhaust discharge louvres, engine fumes or other external airborne contaminants

Exhaust-air Air drawn or expelled to atmosphere from an enclosed space

Centrifugal Fan A fan in which the air enters the impeller axially and is discharged radially

Mixed Flow Fan A fan in which the air enters the impeller axially and is discharged both axially and radially hence mixed flow

Free Cooling The use of unconditioned outside air to limit the temperature rise in a given area

Gas Hydrocarbon and other hazardous gases present on a facility

Manned Area Areas on a facility where personnel are normally present during operations

Supply-air Air delivered to an enclosure in order to ventilate/pressurise the area served

Transmission A measure of the heat flow rate by conduction through a wall or structure in W/m² °C

Unmanned Area Areas on a facility where personnel are not normally present during operations, but may be present only during maintenance/servicing

Velocity Pressure Vp

The pressure of a fluid exerted in the direction of flow





1.6 ABBREVIATIONS AHU Air Handling Unit

AIRAH The Australian Institute of Refrigeration, Air-Conditioning & Heating

AS Australian Standard

ASHRAE American Society of Heating, Refrigeration & Air-conditioning Engineers

CHW Chilled Water

CIBSE Chartered Institute of Building Service Engineers

DX Direct Expansion

Db Dry Bulb Temperature

dB (A) Sound Pressure Level in Decibels (A scale)

ESD Emergency Shut Down

FCU Fan Coil Unit

F&G Fire and Gas

GRP Glass Reinforced Plastic

HDG Hot Dip Galvanised

HVAC Heating, Ventilation and Air Conditioning

LEL Lower Explosive Limit

LQ Living Quarters

Pa Pascals

QRA Quantitative Risk Analysis

RH Relative Humidity

TR Temporary Refuge

TW Tempered Water

Wb Wet Bulb temperature





2 PRIMARY GUIDANCE

2.1 FORMATIVE CONSIDERATIONS The evaluation of any HVAC system must reflect the specific needs and HVAC functions necessary to satisfy the hazardous area classification, the enclosed space internal environmental conditions and any other specific requirements.

Early resolution of the following considerations will ensure the appropriate HVAC basis of design is developed accordingly: -

• Provide early design input so that electrical or mechanical HVAC plant and equipment is sited in an optimum location so far as is reasonably practical (non-hazardous areas are preferred)

• Adopt a consistent HVAC philosophy for the separation of hazardous and non-hazardous areas and select the functions required of the HVAC systems serving those areas

• Determine the internal and external environmental conditions and nominate sensible maximum and minimum parameters that enables cost-effective practical HVAC systems to be developed. Dust particles size need to be established for the design filtration systems for clean rooms as per AS1324.2. Dust particle composition may also need to be established (eg iron filings or conductive particles).

• Implement a basis of design that provides adequate pressurisation, fresh-air ventilation, air filtration, heating, cooling or humidification in line with the nominated internal and external environmental conditions

• Develop the basis of design to provide 100% standby availability for major HVAC plant and equipment; within the constraints imposed by installed cost, maintenance resources and the consequences of plant and equipment failure

• Select a control system that provides operator control from a frequently manned location and also provides the operator with essential information on the status of the plant. The control system must also be integrated with the facility ESD and F&G systems so that actions in an emergency minimise the risk to personnel

• Specify HVAC equipment and components manufactured form materials, or having protective coatings, that minimise lifecycle costs over the operating lifetime of the installation

2.2 HAZARDOUS AREA CLASSIFICATION All areas of any facility fall into either a non-hazardous or hazardous area category. Therefore it is important to recognise the potential impact these areas have in relation to the selection of suitable HVAC equipment and plant.

By adopting a consistent HVAC design philosophy for the distinction between non-hazardous and hazardous areas the appropriate level of protection for HVAC equipment and plant can be ascertained.





2.2.1 HVAC Role for Hazardous Area Enclosures HVAC shall be required where hazardous area enclosed spaces - having some form of solid boundary - will not disperse or remove flammable gases naturally. In such cases these enclosed spaces must have adequate ventilation, normally by means of mechanical ventilation, with no stagnant areas.

The principle roles of the HVAC system are to provide for: -

• dilution, dispersal and removal of concentrations of flammable gas due to fugitive emissions which occur from process components under operating conditions

• reducing the risk of ignition following a leak by quickly removing accumulations of flammable gas to maintain the atmosphere below the LEL

Normally a hazardous area enclosed space requires mechanical ventilation only. However should there be an additional requirement for heating or cooling, all associated HVAC equipment and plant must have appropriate protection for the hazardous area classification and be fully integrated with the ESD and F&G systems.

2.2.2 Minimum Ventilation Rate Based on the recommendation of IP Area Classification Code for Petroleum Industries, Model Code of Safe Practice, Part 15; ventilation rates for mechanically ventilated enclosed spaces located in hazardous areas shall comply with the following criteria: -

• A minimum of 12 air changes of the enclosure per hour

• The enclosure should not contain stagnant areas (ie should be 'well-mixed')

It should be noted that there is no formal definition of the term 'stagnant area'. It is taken to be any area within an enclosed space in which there is no discernible air movement. No single stagnant area should exceed 5% of the total enclosed space volume.

The “12 air changes per hour” figure is intended to be sufficient to rapidly remove gas after a small leak. In well-mixed areas 3 air changes will make an area safe.

eg: 100% gas will dilute to a concentration of less than 5% after just 3 complete air changes – consequently for spaces having 12 air changes per hour the time taken to dilute below 5% takes 15 minutes

For enclosures that are 'well-mixed' it has been demonstrated that enclosure volume is not a factor and that it is the leakage rate of flammable vapours that directly determines the rate of ventilation required. It follows that in using the criterion of 12 air changes per hour, ventilation rates for small leakages of flammable vapours may be much higher than are actually required.

Alternative methods for determination of the ventilation rates are available by predicting the flammable gas leakage rate or utilising sophisticated computational





modelling. These methods are subject to considerable uncertainty and not preferred. The adoption of a fixed number of minimum air changes, in this case 12 air changes per hour is favoured. Any deviations below 12 air changes per hour criteria should be considered carefully and submitted in accordance with the WEL deviation procedure.

Where enclosed spaces also include a requirement for heating or cooling (free cooling or mechanical cooling) the minimum default 12 air changes per hour must be maintained regardless of any impact to heating or cooling load considerations.

2.2.3 Non-hazardous Areas Non-hazardous areas normally do not require the same level of equipment protection as compared to equipment located in hazardous areas.

However, in certain instances there may be a requirement for special protection techniques for some HVAC equipment, despite being located in a non-hazardous area. This requirement may be applied where HVAC equipment must operate during an emergency, or when purging is desired at initial start-up, or re-start following an incident or emergency. Typically this may apply to supply-air fan drive motors and electrical equipment associated with the main AHU.

2.2.4 Hazardous Classifications Hazardous areas are divided into two distinct hazard classes, Class I for gases or Class II for dusts. For oil and gas facilities, the class of hazard adopted is normally Class I. Additionally a Class I hazard is subdivided into three area classifications as follows: -

Zone 0 A flammable atmosphere continuously present or present for periods longer than 1000 hours per year

Zone 1 A flammable atmosphere likely to occur during normal operation for periods longer than 10 hours per year but less than 1000 per year

Zone 2 A flammable atmosphere not likely to occur, and if it occurs will exist for short periods less than 10 hours per year

All HVAC equipment and plant required to operate within a classified hazardous area location, shall be specified and selected in accordance with the appropriate protection techniques as required for the hazardous area classification.

2.2.5 Equipment Protection Techniques The latest versions of the following Australian Standards are adopted by WEL for equipment protection requirements for all areas on new facilities and major developments or upgrades to existing facilities.

AS-2380 Electrical Equipment for Explosive Atmospheres – Explosion Protection Techniques

AS-2381 Electrical Equipment for Explosive Atmospheres – Selection, Installation and Maintenance





The following listings give an outline of acceptable equipment protection techniques for each type of zone classification.

Zone 0 Ex ia Intrinsic safety Ex s Special protection (approved for Zone 0) Zone 1 Zone 0 protection techniques acceptable Ex d Flameproof Ex ib Intrinsic safety Ex p Pressurisation for Zone 1 Ex p1 Purging for Zone 1 Ex m Encapsulation Ex e Increased safety Ex v Ventilation for Zone 1 Ex s Special protection for Zone 1 Zone 2 Zone 0 and Zone 1 protection techniques acceptable Ex n Non-incentive Ex p Pressurisation for Zone 2 Ex p1 Purging for Zone 2 Ex v Ventilation for Zone 2 Ex s Special protection for Zone 2

2.3 ENVIRONMENTAL CONDITIONS Incorrect evaluation of meteorological data and environmental conditions can lead to impractical maximum and minimum criteria being nominated for the basis of design.

For instance, the maximum external dry bulb air temperature and maximum humidity values rarely coexist. However, if these maximum values are adopted as the basis of design, unnecessary, oversized HVAC plant capacities - particularly cooling plant capacities – are developed; thereby catering for a small proportion of the year when meteorological extremes are encountered, while for the remainder, the cooling plant operates inefficiently with poor system control.

Consequently a careful assessment of meteorological data is required to ensure nominated design parameters prescribe cost effective HVAC systems that meet realistic capacity requirements. Additionally it is also accepted that internal space temperatures may rise above maximum design for short periods during extreme meteorological conditions.





2.3.1 External Meteorological Conditions Seasonal extremes of temperature, humidity and wind-speed vary widely throughout the world. Accurate meteorological and oceanographic data for the specific offshore location should be obtained for each facility. Where this information is not readily available, a qualified Meteorologist and/or Oceanographer should be engaged to supply the maximum and minimum values of the following criteria over a typical calender year: -

• dry bulb temperature – Db °C

• wet bulb temperature – Wb °C

• relative humidity - % RH

• seawater temperature – °C

• wind speed – m/s

The nominated design parameters for HVAC systems should be based on the actual meteorological conditions as applied to the following table: -

Criteria External Summer Design External Winter Design Dry bulb temperature °C 2% probability of exceeding all

year maximum average 2% probability of falling below all year minimum average

Wet bulb temperature °C

2% probability of exceeding all year maximum average

2% probability of falling below all year minimum average

Relative humidity %RH



Seawater temperature °C



Wind speed m/s 1/12th annual average 1hr mean velocity at 10m reference height

1/12th annual average 1hr mean velocity at 10m reference height

Dust particle characterisation in reference to the AS 1324.2, must be carried to establish local conditions unless they have been established.

Internal pressurisation must be used as the primary method of preventing dust and moisture ingress (e.g. electrical and electronic equipment rooms) unless otherwise agreed by the Technical Authority.





2.3.2 Internal Space Conditions Depending on the category of enclosed space, the internal environmental conditions must be maintained between acceptable predetermined parameters. Therefore, where applicable, the HVAC system must be capable of maintaining internal conditions for the comfort of personnel and/or the safe operation of mechanical and electrical equipment by close control of the following internal parameters: -

• dry bulb temperature

• relative humidity

• noise

• pressure

Dry Bulb Temperature During summer design conditions, internal temperatures may be maintained at acceptable internal space conditions by fresh-air ventilation only (free cooling) or by using mechanical cooling plant ie refrigeration cooling systems.

Where external maximum air temperatures are high the use of fresh-air ventilation (free cooling) may be impractical or unable to maintain acceptable internal space conditions. In such cases a refrigeration cooling system is unavoidable.

Also for enclosed spaces that are fitted with sensitive equipment or instrumentation, the internal temperature shall be determined by the conditions required for acceptable performance of the equipment or instrumentation.

During winter design conditions, internal temperatures may be maintained at acceptable conditions by use of duct mounted electric heater banks or reverse cycle heating.

For normally unmanned hazardous area enclosed spaces, heating should not be provided unless a specific need is justified. In such cases temporary portable heaters suitable for the area classification may be more appropriate than providing duct mounted electric heater banks.

Relative Humidity It is not usually necessary to provide close control of the internal relative humidity, providing the relative humidity is maintained between 40% and 65% in selected areas, such as the LQ to protect the health of the occupants and in electrical equipment rooms to prevent the formation of condensation.

It is critical to ensure good mixing of cooled supply air occurs before entering the conditioned space. This is particularly important when there is a possibility of cool air blowing onto electrical or electronic equipment and possibly creating a cold surface on which condensation may occur.

For LQ’s relative humidity is usually maintained at acceptable internal conditions by operation of cooling plant associated with the HVAC system. During the (wet coil)





cooling process, dehumidification occurs simultaneously thereby removing excess moisture.

Should exceptionally low relative humidity be experienced, it may be necessary to install electric steam injection humidifiers at the AHU. Typically humidification may be provided for the comfort of personnel within LQ’s or for electrical equipment rooms to ensure undesirable electrostatic conditions do not occur. However humidification is usually not seen as critical for any other enclosed spaces and in most cases can be omitted.

Noise There are many factors that contribute to noise generation from a HVAC system. Rotating machinery such as fans, pumps and refrigeration compressors can generate excessive localised noise breakout. However fans and high air velocities that transmit excessive noise through ductwork are the principle sources of unacceptable noise transmission generated by a HVAC system.

A comprehensive analysis should be performed to demonstrate the noise contribution from the HVAC system and adequate steps should be taken to minimise all excessive noise.

Installation of sound attenuators should be considered to eliminate or reduce noise transmission through ductwork. Also all major HVAC rotating machinery should be installed with anti-vibration mounts and be located within an acoustically insulated HVAC plantroom where possible.

The following table offer’s guidance for acceptable internal space conditions for typical enclosed spaces encountered on facilities: -

Pressurisation Pressurisation can be used to prevent ingress of both hydrocarbons and dust/humid air into an area.

Pressurisation for non-hazardous areas typically range 25-60 Pa. Pressurisation for dust air ingress prevention need only be >10Pa although care must be taken to ensure that there are no areas of negative pressurisation (relative to external atmospheric pressure) in the entire system (e.g. ducting upstream of circulation fans)





Area Description M

anne

d 20

– 2

6°C

db

Un-

man

ned

15 –

27°

C d

b

Un-

man

ned

15 –

35°

C d

b

Comments

Living Quarters Cabins Toilets/showers Dining rooms Recreation rooms Offices Meeting rooms Galley Galley stores Laboratories Control rooms Equipment rooms Workshops Locker rooms Plant rooms

X X X X X X X X X X X X X

X X

X

Corridors, toilets, locker

rooms, stairs and galley may have a minimum of 16°C

Utilities Switchrooms Equipment rooms Workshops Battery rooms

X

X X

X

Temp may also be determined by sensitivity of

instrumentation

Some batteries may have specific max. temp

requirements

Emergency generator rooms Fire pump rooms Engine rooms

X

X X

When outdoor ambient is 35°C max temp of 47.5°C

permitted

The maximum sound power levels in conditioned spaces must be as per the ‘satisfactory’ levels specified in AS/NZS 2107.





3 BASIS OF DESIGN

3.1 FACILITY LAYOUT It is not the intention of this standard to detail a facility layout philosophy, but to identify optimum locations for essential aspects of the HVAC system to ensure safe effective operation and performance.

The facility layout requires a great deal of coordination between the engineering disciplines involved in design, operation, maintenance and safety. However, the major consideration in platform layout and HVAC philosophy is likely to be risk, whether measured in terms of potential harm to personnel, the asset or the environment. QRA should be undertaken during the project conceptual design phase to evaluate the risk benefits of alternative layout arrangements including consideration of various HVAC options.

3.1.1 Temporary Refuge Each facility should have a 'Temporary Refuge', which may be an enclosed space or an open area, to ensure personnel can seek refuge in the event of a major incident or emergency. In virtually all cases the TR should be the LQ, where one is provided.

For each facility a detailed risk assessment of the location of the LQ or TR should be undertaken as part of the design verification. The TR should also comply with Shell DEP 37.17.10.11-Gen.

The location of the LQ and the associated means of evacuation to avoid the consequences of radiation and smoke effects are of paramount importance. Hazardous areas, particularly high-pressure hydrocarbon systems, should be located as far as practicable from the TR so that any gas emissions are naturally dispersed.

The maintenance of TR life support is directly related to the availability of breathable air and the provision of a barrier from all external emergency conditions for the duration of the ‘Endurance Period’. The endurance period of the TR is the period for which integrity of the TR structure and TR life support can be maintained.

In the event of an emergency where the HVAC system is shutdown, the gross internal volume of the TR should be able to provide the entire complement of personnel with sufficient quantities of breathable air for the full duration of the endurance period. An air volume of 1.2m³ provides one person with one hour of breathable air.

In the event of an emergency condition where gas or smoke has not entered the HVAC fresh-air inlet, the HVAC system may continue to operate. However should gas or smoke be detected at the fresh-air inlet then the HVAC system must be shutdown immediately, concurrent with the automatic closure of all external boundary penetrations (all fresh-air intakes and exhausts) to prevent the ingress of gas or smoke into the TR.

Emergency HVAC systems and those specifically designed to operate during emergency conditions are the only exception. These systems are permitted to continue operating by virtue of recirculating 100% supply-air while all associated





external boundary penetrations are automatically closed to prevent the ingress of gas or smoke into the TR.

Should the facility LQ be identified unsuitable for TR purposes, a passive arrangement such as a protected open TR area may be preferred since it will not rely on any equipment functioning under emergency conditions.

3.1.2 Equipment Location In general, facilities are designed such that areas classified “Hazardous Area Zone 0” do not require HVAC.

Facilities should also be designed to avoid, where possible, HVAC equipment and plant being installed or sited in a Hazardous Area Zone 1 or 2 location. Where this is unavoidable, the equipment shall be selected as required to meet the protection techniques of the hazardous area classification.

The preference is for all major HVAC equipment and plant to be located in non-hazardous areas and installed within a dedicated HVAC plant room where feasible.

3.1.3 General Arrangements An independent dedicated HVAC system should be provided to serve the following enclosed space configurations: -

• any sole enclosed space

• multiple enclosed spaces integrated by a common structure or boundary with a uniform hazardous area classification

Under no circumstances should a single HVAC system be permitted to simultaneously serve a combination of various hazardous and non-hazardous enclosed spaces, or serve multiple enclosed spaces that are structurally segregated and remote from each other.

Each independent HVAC system should be contained within and/or attached to the external structure of the space or spaces served, and also be suitable for the applicable hazardous area classification.

In some instances the independent HVAC systems major equipment or plant may be sited in a non-hazardous location despite serving an enclosed space(s) located in a hazardous area. Normally this arrangement involves installation of ductwork into the hazardous space only. However selected HVAC equipment may still be required to meet specific protection techniques regardless of their non-hazardous location. Also where rated bulkheads or boundaries are penetrated by ductwork, they must be fitted with certified fire dampers to ensure the integrity of adjacent hazardous and non-hazardous spaces.





3.1.4 HVAC Fresh-Air Intakes and Exhausts The facility layout should include careful positioning of all HVAC fresh-air intakes and exhaust-air outlets in relation to gas turbine and engine intakes/exhausts, vents and flares to allow for safe operation. In particular, HVAC fresh-air intakes should be located to avoid cross contamination from: -

• exhausts from fuel burning equipment, gas turbines and generators

• lubricating oil vents, drain vents and process reliefs

• dust discharge from drilling, dry powders

• helicopter engine exhaust

• flares

• supply and support vessels

Particular care should also be taken locating HVAC fresh-air intakes and exhaust-air outlets in relation to other independent HVAC systems serving adjacent hazardous and non-hazardous areas.

All fresh-air intakes serving hazardous or non-hazardous enclosed spaces should be located at the maximum practical distance from hazardous areas, irrespective of minimum distances specified by relevant regulations, standards or codes.

Where possible all exhaust-air outlets should exhaust to non-hazardous areas and also be located at the maximum practical distance from hazardous areas. Where this is not feasible and exhaust-air is discharged to a hazardous area, then the enclosed space must also be pressurised if required to maintain a non-hazardous classification. Pressurisation is not required if the enclosed space is also classified as a hazardous area.

The underside of a platform can be a convenient location for HVAC fresh-air intakes and exhaust-air outlets as a large proportion of this zone may be classified as non-hazardous. However, consideration should be given to the effects of the wind and waves and below platform cooling water discharges.

For floating production vessels the downwind zone may provide an appropriate location for HVAC fresh-air intakes and exhaust-air outlets. However, they should be positioned to avoid ingress of smoke or contaminants from engine rooms and capable of operation in adverse winds.

Wind Effect The location of HVAC intakes and exhausts should be carefully considered in relation to prevailing wind directions for fixed facilities and weather vane affects for floating production vessels. Locations that provide shelter or protection from the wind are preferred so as to minimise strong wind conditions from adversely affecting fan performance and pressurisation.





All HVAC fans should operate satisfactorily in wind conditions varying from still air to design wind speed. A contingency margin should be included in the design to ensure the fan performance requirements are met during adverse wind effects.

3.2 TYPES OF HVAC SYSTEM The type of HVAC system best suited for each application will vary according to the physical size and capacity of the HVAC plant required, the hazardous area classification and the physical space limitations that are unique to each individual facility.

There are two main aspects to consider for the development of an HVAC system concept. Principally does the HVAC system necessitate mechanical ventilation only or mechanical ventilation including the means to provide heating and/or cooling.

In both instances a mechanically powered fan system, air handling system or a multiple combination of systems is required to provide air movement and distribution usually via associated ductwork. The array of fan types is extensive, ranging from a single fan unit to fans available as an integral component of an equipment package or AHU.

In spite of many types of HVAC system design or arrangements being available, there are only a limited number of suitable designs that also meet the operating requirements for an facility.

All HVAC systems shall incorporate the constant volume method of delivering air to enclosed spaces and under no circumstances should variable air volume be considered. The constant volume method of delivering air ensures pressurisation where required, satisfies air change rate and fresh-air rate requirements, and enables terminal reheat units to be utilised for close temperature control.

The most common types of HVAC system arrangements are shown in the table below: -

Type of HVAC Equipment

Application Comments

Ventilation only – Fan assisted supply-air systems

General supply-air 100% fresh-air/free coolingPressurisation

Usually serves single space only Limited cooling capacity

Ventilation only – Fan assisted exhaust-air systems

General exhaust Galley exhaust Toilet exhaust

Usually operate in conjunction with supply-air systems

Room Air Conditioning Unit

100% recirculated air Emergency cooling and/or heating

Serves single space only Temperature control limited to single space

Split Air Conditioning Unit

General supply-air Pressurisation Cooling and/or heating

Usually serves single space Must have fresh-air make up arrangement to provide pressurisation Temperature control usually





limited to single space Centralised AHU With Cooling by:

General supply-air Pressurisation DX Refrigeration

Serves multiple spaces Must have fresh-air make up arrangement to provide pressurisation Practical cooling capacity limited to 400kW per system, no provision for future expansion

Type of HVAC

Equipment Application Comments

AHU cont. With Cooling by:

Central chiller plant with CHW circuit

No cooling capacity limits, may serve multiple AHU or FCU, provision for future expansion

Fan Coil Unit (FCU) General supply-air Cooling

Usually recirculated supply-air only Relies on central chiller plant to circulate secondary cooling medium (ie water)

3.2.1 Mechanical Ventilation Mechanical ventilation is suitable when sufficient free cooling occurs to maintain the enclosed space within the internal design parameters - without the requirement of a cooling system ie refrigeration plant.

Clearly mechanical ventilation (free cooling) should be used wherever practical and is dependent on accurate meteorological and environmental data from the project location, to evaluate the free cooling capacity potential. The cooling capacity available by adopting the free cooling method is reduced when also considering heat gains from fans, fan motors, ductwork, personnel, equipment and heat transmission through bulkheads of the space(s) served. Where there is less need for precise temperature control such as for unmanned utility and equipment rooms then free cooling may be adequate.

When mechanical ventilation is nominated to serve an enclosed space or spaces, it should provide the following functions: -

• pressurisation (if required to maintain non-hazardous enclosed space)

• a minimum of 12 air changes per hour

• adequate free cooling





• Various mechanical ventilation system configurations are possible. The adopted configuration will depend on the application and type of enclosed space requirements. Common configurations are: -

• supply-air fan(s) & exhaust-air fan(s)

• supply-air fan(s) & natural exhaust-air

• exhaust-air fan(s) & natural supply-air

3.2.2 Heating It is usual and straightforward to provide heating by means of incorporating electric heater banks in the supply-air ductwork or AHU. Main or large capacity heater banks are normally mounted within an AHU, while smaller capacity heaters are mounted in terminal reheat units. Terminal re-heaters are usually installed in the ductwork supply branch serving single or limited multiple spaces to provide close temperature control.

The primary concern with heater banks is to select electrical equipment that satisfies the area classification and incorporates all associated safety and temperature limiting devices. Electric heater banks must also meet stringent regulations for the degree and type of thermal insulation required for fire protection.

In some instances hot water heating coils may be considered. However they are not commonly installed where in most cases a suitable hot water recirculating system is not continuously available. Additionally they may take up valuable AHU space already restricted by incorporating standby equipment.

While other methods of providing heating may be available, electric heater banks are preferred, as they offer the most compact arrangement and can accommodate hazardous area protection requirements without difficulty.

3.2.3 Cooling Whenever the enclosed space internal environmental conditions cannot be maintained within the specified limits by use of free cooling then cooling must be provided by a refrigeration system.

Many options are available to provide adequate cooling. The options range from a simple room air conditioner up to a central type air handling plant incorporating an intricate refrigeration system. The selected cooling option depends on the layout, configuration, cooling load, space restrictions and accuracy of temperature control.

3.2.3.1 Room Air Conditioners These are small fully contained single piece units used for supplying conditioned air to single spaces only. Limited in cooling capacity, and primarily recirculation air type units, the whole unit is mounted into a wall penetration with no associated ductwork being connected. These units can provide supplementary cooling for spaces with high equipment heat gains and may also be configured to provide cooling during emergency conditions.





Where room air conditioners are used to provide supplementary cooling during normal operating conditions, the primary fresh-air supply is usually supplied via the central air handling system.

To avoid large wall penetration complications for mounting of the whole unit, it is advisable to use split units having an indoor fan unit connected by refrigeration pipework and control cabling to a remote air-cooled condensing unit.

3.2.3.2 Packaged Air Conditioning Units Packaged units may be single piece or split type arrangements used for supplying conditioned air to single, or a limited number of, spaces and can be installed with or without distribution ductwork. They are recommended when it is not practical to install a central AHU and associated refrigeration plant.

Packaged units as they imply, contain the supply-air fan, cooling/heating facilities and electrical starting gear and controls in a complete package. For single piece units the refrigeration condensers are water-cooled whereas for split type or two piece units the condensers are remote and air-cooled. Cooling facilities are always provided by means of a DX refrigeration circuit while heating can be provided by reversing the refrigeration circuit (ie reverse cycle) or by electric heating elements.

3.2.3.3 Central AHU with Refrigeration Plant Central AHU’s are used for supplying conditioned air via ducting networks to multiple enclosed spaces simultaneously and are recommended for serving entire LQ’s, or enclosures with multiple spaces.

Usually central AHU’s operate in conjunction with general, galley and toilet exhaust-air systems and may be designed to operate on a total loss basis (100% fresh-air) or a combination of fresh-air mixed with return-air. The mixture ratio of fresh-air to return-air is dictated by the quantity of exhaust-air that must be exhausted directly to atmosphere, the cooling load capacity requirement and the physical space limitations for installation of the supply and return air ductwork.

A dedicated refrigeration plant with associated CHW or DX coils mounted in the AHU supplies the cooling requirements. The primary difference between CHW and DX systems are that CHW systems circulate secondary cooling mediums (chilled water) through the cooling coil whereas DX systems circulate the primary cooling medium ie refrigerant through the cooling coil (also known as the evaporator coil).

CHW systems typically consist of a centralised package chiller set incorporating a compressor(s), refrigeration circuit(s), a condenser, an evaporator and all necessary controls, starting gear and instrumentation. The chiller set is connected to a closed loop CHW piping circuit usually incorporating duty and standby CHW pumps, which in turn serve CHW cooling coils mounted in the central AHU. CHW systems are extremely versatile; they provide accurate temperature control and can be sized to provide for future cooling needs by serving additional AHU’s as required.

DX refrigeration systems consist of a compressor set or condensing unit coupled by refrigeration pipework to a remote evaporator coil mounted in the central AHU. The DX refrigeration system supplies liquid refrigerant directly to the evaporator coil





where direct expansion of the refrigerant takes place - hence the term DX. DX systems are usually limited to serving the evaporator coil(s) of a single AHU and therefore do not allow for future additional cooling systems.

CHW and DX systems can both accommodate air-cooled or water-cooled condensing media. The merits of which condensing medium is suitable must be evaluated by careful analysis and consideration of the facility cooling water system, the location of main refrigeration plant and the available space for locating external air-cooled condensing equipment. Where practical, the preference is for air-cooled condensing equipment to avoid reliance on cooling water systems and prevent down time associated with maintenance and cleaning of water-cooled condensers.

Where refrigeration equipment may be required to operate under emergency conditions they shall incorporate air-cooled condensers only.

3.2.4 Floating Production Vessels For HVAC systems on board floating production vessels, special attention is drawn to the appropriate certification body such as ABS, Lloyd’s and AMSA rules and regulations. Generally where the HVAC basis of design adopts the general principles of this code then these requirements should be easily met.

Essentially for shipping vessels either with or without propulsion equipment, the type of construction includes multiple internal bulkheads and decks and offers limited service or ceiling void space for the routing of ductwork.

As such, the applicable rules and regulations permit ductwork having a cross-sectional area of no more than 0.75m² to pass through bulkheads and decks without the need for fire dampers (providing the penetration is suitably constructed and fire rated). Consequently this anomaly, in conjunction with limited space for routing of ductwork, may steer the design towards adopting a high velocity ductwork system and in doing so, reduce the number of fire dampers required.

Where feasible, low or medium velocity ductwork designs are preferred including fire dampers located at all rated bulkhead penetrations and where necessary all non-rated bulkhead penetrations.

3.3 CONTROLS PHILOSOPHY The philosophy outlined in this section is representative of good engineering practice on large, integrated facilities. Some aspects may not be appropriate to smaller facilities or normally unattended facilities where HVAC may not be considered to have a role in asset protection.

The HVAC control philosophy must provide the operator with the following control and monitoring functions from a frequently manned location such as the central control room: -

• executive override control for normal and emergency operation

• normal and alarm status of major HVAC plant

• fire and gas damper indication at the main F&G panel





The HVAC control philosophy must also be integrated with the facility ESD and F&G systems to initiate automatic HVAC plant shutdown when required to do so in the event of an emergency incident.

In the event of a gas release, the objectives are to dilute and remove the resulting gas cloud and limit migration to other areas. The strategy to achieve this is normally to: -

• Upon gas detection inside an enclosed hazardous area – continue operation of the HVAC system to dilute and remove the gas

• Upon gas detection at any HVAC fresh-air inlet – shutdown the HVAC system to prevent external gas being drawn in and propagated by the HVAC system

• Upon gas detection inside an enclosed non-hazardous area – shutdown the HVAC system as it is assumed that gas is being drawn in from other areas and should not be propagated by the HVAC system

In the event of a fire, the objectives are to prevent any external smoke entering the enclosed space via the HVAC fresh-air inlet and to prevent any fire or smoke generated within an enclosed space form being propagated to other areas via the HVAC system. The strategy to achieve this is normally to: -

• Upon smoke or fire detection at any HVAC fresh-air inlet – shutdown the HVAC system to prevent external smoke or fire being drawn in and propagated by the HVAC system

• Upon smoke or fire detection inside an enclosed hazardous or non-hazardous area – shutdown the HVAC system as it is assumed that an internal fire has occurred and should not be propagated by the HVAC system

The HVAC system design should therefore incorporate adequate fire-rated fire dampers that automatically operate to prevent gas or smoke ingress and/or propagation. In particular the HVAC system design shall provide for: -

• Fire-rated ductwork penetrations through fire-rated boundaries, bulkheads or decks, provided with fire-rated fire dampers equal to the rating of the boundary they penetrate

• HVAC fresh-air inlets serving non-hazardous enclosed spaces shall be provided with fire dampers that automatically close upon detection of gas or smoke at the inlet

• Fire dampers shall automatically close (and where appropriate HVAC shall be shutdown) to isolate segregated areas upon internal detection of fire or smoke

Alternative shutdown philosophies may be adopted but it is important that they are consistent with the facility ESD and F&G philosophies.





3.3.1 Control and Monitoring - Normal Operation 3.3.1.1 Integrated HVAC Panels

An HVAC console should be located within the central control room or a similar normally manned room to provide the operator with HVAC executive override control for normal and emergency operation that also provides status and alarm conditions. All controls, status and alarm indicators should be set out in logical functional groups and be easily identifiable. As a minimum, the degree of operator override control should allow for: -

• HVAC system shutdown

• closure and opening for all fire dampers

HVAC alarms should allow for “loss of pressurisation” and “general group equipment alarms”. The provision of alarms for specific items of equipment, upon failure, is considered unnecessary. The preferred option is to provide group equipment alarms for each system or equipment package so that further investigation must be conducted to identify the exact nature of the fault at the central HVAC panel or equipment package. Where standby equipment is installed, it should automatically start-up allowing the failed duty equipment to be investigated in a timely manner following a group equipment alarm.

For HVAC control systems that are fully integrated with the facility central control system, a digital graphic display screen with complete HVAC system control and monitoring should be provided for the operator. Where this type of control arrangement is adopted, major HVAC equipment may be powered directly from a motor control centre without the need for a dedicated HVAC starter panel.

3.3.1.2 Dedicated HVAC Panels A dedicated central HVAC panel may be provided to enable complete HVAC system control and must be interfaced with the facility ESD and F&G safety systems, and also any ancillary control panels.

In the case of specific plant packages that are supplied already fitted with a control/starter panel, such as for packaged refrigeration equipment, steam humidifiers etc, they shall be interlocked with the dedicated central HVAC control panel.

All controls and indicators associated with HVAC panels should be set out in logical functional groups. Typical arrangements would be as follows: -

SELECTOR SWITCHES / PUSHBUTTONS:

Start & stop pushbuttons

All fans

Open - Close selector

All fire dampers – protecting fire rated bulkheads or providing boundary isolation for TR

Auto-Man –Off selector

All duty/standby fan arrangements Duty/standby refrigeration plant Duty/standby CHW pumps





Lamp test pushbutton

Common test pushbutton for all indicator lamps

INDICATORS:

Running All fans

Stopped All fans

On Each package equipment item All heater banks

Tripped All fans Each package equipment item Heater banks

Dirty filter All filters (excluding coalescers or vane separators)

Open & closed All fire dampers – protecting fire rated bulkheads or providing boundary isolation for TR

Loss of pressurisation

All non-hazardous areas (eg LQ) adjacent or connected to a hazardous area

ALARMS:

Smoke detection Optionally alarmed via F&G system only

Gas detection Optionally alarmed via F&G system only

Loss of pressurisation

All non-hazardous areas (eg LQ) adjacent or connected to a hazardous area

Common group alarm

Fan trip Package equipment trip Heater trip Dirty filters High/low humidity (if applicable)

Fire damper open and closed indication should be repeated at the F&G panel, particularly in the case of TR boundary dampers where the location of a damper that has failed to close needs to be established quickly to ensure the integrity of the TR.

To generate equipment indication the following instrumentation shall be provided: -

Fan Status Provide proximity sensors to monitor fan drive shaft rotation (especially for belt driven fans). The sensors should be calibrated to identify speeds below 80% of fan full speed and be integrated with the control circuitry to provide fault indication and initiate automatic fan changeover from duty to standby where applicable.

Alternatively, a differential pressure switch mounted across individual fans or fan sets may be used.





Fire Damper Status Remote indication of open or closed fire damper status shall be provided by two separate micro-switches (one for open, one for closed) supplied as integral components of the fire damper. Additionally the damper shall indicate the open or closed damper position locally at the control box enclosure by means of a mechanical mechanism.

3.3.1.3 Fan Control For non-hazardous enclosures failure of a supply fan shall stop all associated exhaust fans. However failure of an exhaust fan shall not stop any associated supply fans. For start-up of the HVAC system, exhaust fans should be inhibited from starting until the supply fans are energised and operating satisfactorily.

Meanwhile for hazardous area enclosures failure of a supply fan shall not stop any associated exhaust fans. However failure of an exhaust fan should stop its associated supply fan.

A manual start/stop station should be provided locally at each fan.

Galley exhaust fans shall be interlocked with the main supply AHU and/or galley supply-air fans.

Exhaust fans serving local fume producing activities or equipment such as welding/paint spraying booths and laboratory/fume cupboards, should be provided with start/stop control and status indication local to the equipment or working position.

3.3.1.4 Fire Damper Control Control of fire dampers to initiate opened/closed positioning should be via a control signal from one or more of the following four sources: -

• remote operation from the main HVAC panel

• remote operation from the HVAC console in the central control room

• automatic operation by the facility ESD and F&G systems

• fail safe closure by rupture of an integral frangible bulb or trigger device provided with each fire damper

• manual operation from a dedicated fire damper control station located outside the enclosure

Where multiple fire dampers serve the same area or zone, they should be grouped together to automatically operate simultaneously and thereby isolate the zone.

Where multiple fire dampers are operated via independent control loops or circuits then failure of any single damper should not prevent the normal operation of the remainder.

For pneumatically operated fire dampers, a manual fire damper control station may be provided and located in a safe area outside the main escape exit for the enclosed space(s) served. The control station should incorporate hand operated





three-way pneumatic valves assigned to each individual or group of fire dampers for local manual control.

3.3.1.5 Loss of Pressurization An indication and alarm should be raised when a non-hazardous enclosed space, that is adjacent or connecting to a hazardous area, falls below a minimum pressurisation level. Indication and alarms shall be relayed back to the HVAC console or screen located in the central control room.

To avoid nuisance alarms due to frequent door openings an adjustable time delay should be incorporated. The time delay period should range from between 2 to 5 minutes. Since it is not possible to model the frequency of door openings in relation to the rate of loss and re-instatement of pressurisation, the time delay period is normally determined by empirical means during HVAC commissioning.

When areas are pressurised solely to eliminate ingress of dust and moisture to the room, the alarm can be delayed for 6 hours to reduce the amount of nuisance alarms to the panel operator. The Technical authority may allow alternative means of monitoring pressure if installation of an alarm is not considered practical, e.g. local monitoring during “watch keeping” rounds.

3.3.1.6 Temperature Control Temperature control shall be fully automatic and integrated with the HVAC system.

For centralised HVAC systems incorporating AHU’s, temperature control should be provided by an adjustable programmable PID temperature controller. Temperature transmitters should be mounted at the AHU air-on and air-off locations to provide the temperature controller with analogue input signals (0-10 V or 4-20mA). The temperature controller shall process all input signals and in-turn provide analogue output signals to control the degree of heating or cooling required to maintain the air temperature in the conditioned areas .

For LQ’s or other habitats containing multiple enclosed spaces, adjustable temperature controllers/sensors shall be provided for each room or area. These local controllers shall control the degree of trim heating supplied by the associated constant volume reheat unit to maintain individual room temperatures at the desired room set point.

Room air conditioning units or split air conditioning units shall be supplied with dedicated thermostats or temperature controllers for temperature control.

3.3.2 Control and Monitoring - Emergency Conditions At the dictate of the ESD or F&G systems, HVAC systems shall be shutdown including: -

• isolation of all HVAC equipment power supplies

• closure of all fire dampers





Once shutdown HVAC systems shall be prohibited from being re-started until the emergency has been cleared and the shutdown signal has been reset through the ESD and F&G systems.

An override to the ESD and F&G shutdown signal for smoke exhaust should not be provided since smoke removal using the HVAC systems is not usually a design consideration for facilities.

Upon reinstatement of electrical power HVAC systems should be restarted in accordance with the initial 'start-up' sequence procedure.

Black start ventilation should be achieved primarily by natural ventilation and secondly by portable fans.

Emergency Cooling Emergency cooling is normally provided by independent room air conditioners or split air conditioners for enclosed spaces such as the central control room, emergency switchrooms, electronic equipment rooms, telecom/radio rooms or TR muster areas.

The need for emergency cooling will usually depend on the rate of temperature rise due to heat dissipation from electrical and electronic equipment. Emergency powered air conditioning units should be provided only when maximum operating space temperatures or the permissible "Heat Stress" threshold will be exceeded within the required emergency operating period. It should be recognised that heat dissipated from electrical equipment during an emergency may be significantly less than under normal circumstances. However there may also be residual heat from equipment isolated/shutdown that may increase the rate of temperature rise early in the TR endurance time. Also refer to Shell DEP 37.17.10.11-Gen on TR design.

Air conditioners required to operate in an emergency must be connected to an emergency electrical power supply so they may continue or commence operation.

In most cases they will also need to be of the remote air-cooled condensing type, given that it is unlikely for utility cooling water to be available during an emergency. The air-cooled condenser fan motors and all electrical gear should be suitable for a zone 1 hazardous area classification – despite the possibly of being located in a normally non-hazardous area – since they must operate during emergency conditions where hydrocarbon gas may have been released.

Emergency air conditioners shall recirculate air only – they are not designed to maintain pressurisation and must never be connected to an outside air supply. Outside fresh-air supplied from the central HVAC system shall be isolated in emergencies through closure of associated fire dampers.

3.4 SPARING PHILOSOPHY The sparing philosophy involves addressing the necessity of providing standby equipment arrangements when considering the consequences of: -

• duty equipment reliability under continuous operation

• duty equipment failure

• loss of pressurisation





• loss of cooling to spaces with substantial heat gains

Normally for facilities most HVAC equipment is required to operate continuously 24 hours per day yearly. For some equipment, although it is made available for operation 24 hours per day, there will be occasion when it is idle or operates intermittently – especially in the case of refrigeration plant during periods of minimal cooling loads.

The HVAC design should therefore reflect a high degree of operational reliability and availability to minimise equipment downtime and thereby retain essential HVAC systems. Equipment sparing or duplicate standby equipment is the favoured arrangement by which operational reliability and availability can be assured. For essential HVAC systems 100% standby equipment is preferred to guarantee service continuation and equivalent operating conditions.

For LQ’s that incorporate a centralised AHU, they shall in every instance require a minimum of 2 x 100% supply-air fans (duty and standby) to prevent loss of pressurisation. Ancillary fan systems interlocked with the AHU, such as the galley, toilet or laundry exhaust systems should also be provided with duty and standby fan arrangements.

While 100% or total standby capacity is preferred, it is not always crucial. Reduced standby capacity may be considered adequate where standby operation is temporary or for some refrigeration systems which all, unavoidably, operate with inherent diversity. Similarly, the adoption of 2 x 50% duty fans may be acceptable on some supply or exhaust systems if temporary operation at 1 x 50% presents no risks or dangers for the period required to reinstate a failed fan.

The following table indicates the recommended standby arrangements for typical HVAC equipment: -

Equipment Sparing Comments

Centralised AHU 2 x 100% supply-air fans Rotate duty monthly

Fans – as for LQ’s and general usage

2 x 100% general supply fans 2 x 100% galley supply fans 2 x 100% galley exhaust fans 2 x 100% general exhaust fans 2 x 100% toilet exhaust fans 2 x 100% laundry exhaust fans

Rotate duty monthly for all fan applications

AHU cooling coils 2 x 100% cooling coils Or match refrigeration plant configuration as required

Centralised CHW refrigeration plant

2 x 100% chiller sets 2 x 100% CHW pumps 2 x 100% TW pumps

Rotate duty monthlyRotate duty monthlyNot required if using direct seawater cooling

Centralised DX refrigeration plant

2 x 100% refrigeration units OR 3 x 50% refrigeration units OR 1 x 100% duty refrigeration unit & 1 x 60% standby refrigeration unit

Rotate duty monthly Two 50% units provide total duty –rotate 1 x 50% unit for standbySpace temperature may rise if standby unit required during max cooling load

Emergency cooling 1 x 100% packaged unit Remote air cooled condensing types only





Ventilation only – Hazardous areas

2 x 100% supply or exhaust fans Rotate duty monthly

Ventilation only – Engine room

2 x 50% supply fans OR 4 x 25% supply fans 2 x 50% exhaust fans

Applicable to floating production vessels

Ventilation only – Cargo pumproom

2 x 100% exhaust fans OR 1 x 100% supply fan 1 x 100% exhaust fan

Applicable to floating production vessels

Note that standby equipment is not required for non-essential services or where contingency plans for equipment failure has clearly demonstrated rapid repair or replacement would be implemented immediately.

3.5 MAINTENANCE PHILOSOPHY Due to the high cost of maintenance, HVAC systems should be designed to maximise intervals between maintenance periods, but should also avoid neglect. The emphasis should be placed on planned maintenance, especially for all equipment with customary wear and tear, to prevent minimal equipment failure.

Long term reliability of components, materials and plant is therefore essential and particular attention should be given to lifecycle costs when selecting new equipment. It is therefore important to identify suitable materials and protective coatings for equipment and components that will ensure prolonged effective operation.

Plant should be well placed for ease of maintenance in order to ensure better overall reliability. Lack of withdrawal space inevitably will increase maintenance costs and should be avoided. The following general principals should be followed: -

• plant and equipment should be floor mounted wherever possible

• plant and equipment should have good accessibility

• permanent access platforms should be provided for all items of equipment requiring regular maintenance or inspection, where adequate access from floor level is not possible

• ample head-room and good lighting should be provided

• ample withdrawal/removal area should be provided for all items of plant and equipment

• provide lifting and handling facilities for major equipment items for use during construction and for maintenance

All components requiring regular servicing should have removal and maintenance areas developed and coordinated with other disciplines. Ideally, withdrawal and maintenance areas should be common. Removal routes for large items should be considered for access to and from crane lifting points or lay down areas.





Determination of equipment inspection, maintenance and testing intervals normally depends upon the manufacturer’s recommendations. However, frequencies should initially be set conservatively and modified in line with experience.

The following equipment may typically require maintenance routines as indicated: -

Air filters - 3 monthly (or as required)

Electric heater banks - 3 monthly

Fire dampers - 3 monthly

Fans, including drive belts and bearings

- 3 monthly

Control systems including control panels

- 6 monthly

Humidifiers - 6 monthly

Pumps – CHW and TW service - 6 monthly

Refrigeration plant - 6 monthly

Water cooled condensers serving refrigeration units

- 12 monthly (or as required for direct seawater cooling condensers)

All HVAC maintenance routines must be included in the site computer maintenance system (SAP). Care must be taken with systems that provide pressurisation to prevent ingress of hydrocarbons or sufficient ventilation to prevent the build up of hydrocarbon vapours. There must be at least one recurring work with TI (technical integrity) flag to demonstrate the system is functioning correctly.

3.5.1 Spares To satisfy operational availability and incur minimum costs over the lifetime of the facility, consideration should be given to the following aspects: -

• standardisation of components and holding of spares

• ease of maintenance

• specialised tools

• specialised & qualified personnel

One objective of equipment selection should be to reduce spares stock quantities and to incorporate, where possible, maximum standardisation of components to enable interchangeability between various HVAC systems across the facility. For identical standby equipment it is acceptable to hold a common single spare item. Where possible, selection of air filters, refrigeration filter driers and other consumables should be standardised.

It is also important to ensure any maintenance routines carried out on specialised equipment such as for complex refrigeration plant and controls, are performed by fully trained and qualified personnel. Typically the manufacturers representative may





be utilised to avoid the possibility of spares being misused and squandered by non-qualified personnel.

3.6 MATERIALS AND CORROSION Materials and protective coatings for equipment and components must be carefully selected to maximise the design life of HVAC equipment, and in doing so minimise the lifecycle costs.

All equipment located externally face the harshest conditions and must be selected or constructed to withstand a constant saliferous atmosphere, usually with a high relative humidity, during the entire lifetime of the facility. Most HVAC systems and associated components will also continuously handle large quantities of outside air during normal operation, posing similar harsh conditions. Additionally various corrosive materials may be present and must be equally guarded against.

It is therefore necessary to select HVAC equipment that is designed to withstand these conditions and thereby avoid additional maintenance, service, repair or premature equipment replacement. In all cases, and as a minimum, non-combustible, non-toxic materials shall be used throughout the HVAC system. All materials when heated or on fire shall not emit toxic fumes.

Of the potential sources of corrosion, the following have the largest impact on HVAC equipment: -

• salt aerosols

• galvanic attack

• combustion products

• drilling chemicals in dust, paste and liquid form, comprising but not limited to cement, caustic soda, bentonite and barytes

Salt aerosols, galvanic attack and combustion products occur throughout all facilities while drilling chemicals are mainly concentrated around drilling storage areas and may be carried as wind dusts to surrounding areas following release from storage tank vents or dump chutes.

Corrosion can be significantly reduced by adopting prevention philosophies that: -

• minimise corrosion opportunity by control of the environment eg by humidity control and effective air filtration etc

• use inherently corrosion resistant materials and/or protective coatings

• use corrosion allowances to extend the life period before replacement

Stainless steels, typically type 316, are preferred as a means of minimising corrosion. However alternative and composite materials may be considered where stainless steel may be impractical.

Aluminium’s low melting point and potential for friction sparking when combined with rusting mild steel shall exclude its use on facilities. The only exception to this rule is





the accepted use of anodised or enamel coated aluminium grilles and diffusers when installed within non-hazardous enclosed spaces such as LQ’s.

Ductwork Generally all ductwork shall be fabricated from stainless steel type 316 sheet.

For short design lives, for example on upgrade or refurbishment work, it may be acceptable to manufacture external ductwork from mild steel sheet provided it is painted or HDG after fabrication. Additionally, depending on local contractor capability, fabrication facilities and available materials it may not be possible or cost effective to manufacture stainless steel ductwork in some instances.

Fans Impellers shall be made from inherently non-corroding materials such as stainless steel type 316 or GRP. Fan casings should also be constructed from stainless steel type 316 although mild steel may be used providing they are HDG after manufacture.

Consideration should also be given to the sparking potential of fans. Non sparking constructions that includes brass rubbing rings or plates for stainless steel fan inlet cones and belt guards shall be adopted for all fans.

3.7 DESIGN CALCULATIONS Design calculations may be performed either by manual calculation or by using a recognised computer software program such as “Camel”, “Carrier EII-20”, “Trane Tracer” or equivalent recommended by AIRAH, ASHRAE, CIBSE or similar institute.

Calculations should be presented on standard A4 size sheets or computer print-outs with each sheet bearing a title, date and signature of the HVAC engineer and approval authority. Calculations must be revised and updated as required by the development of the project or other unforseen changes until final detail design has been completed.

Fans Fans should be selected to operate on the steep part of their performance pressure/volume curve to ensure minimal airflow fluctuations during adverse wind conditions. The operating point shall be the required airflow rate where the system pressure is based on the actual system resistance for ductwork and fittings, cooling coils, filters (average dirty pressure drop) and 50Pa pressurisation effect (where required).

Where practical, the fan and motor should be selected to cater for speed increases to compensate for system deterioration or possible future modifications to the ductwork routes.

Arrangements with duty/standby fans should be selected so that the fans are capable of starting against a 5% backdraught airflow. Depending on the arrangement and quality of the associated fan shut-off dampers, a contingency of up to 5% should be added to the fan design duty to compensate for air recirculated through the standby fan and shut-off damper.

Fan Contingency To prevent gross over-sizing of fan duties the design engineer must demonstrate that any contingency is fully justified and has taken into account: -





• the maturity of the design and subsequent confidence in the ductwork routing and nominated airflow rates

• the impact of contingencies in relation to the required fan motor size

Hence, high airflow resistance due to excessive contingencies may double the size of smaller fan motors although this is unlikely to create a problem. However for larger fan motors this may cause unacceptable increases to the power supply, cabling and switchgear required.

Wind Loading

A value of design wind speed corresponding to a probability of exceedance of 5% from any compass direction should be used, with the effect being calculated using a recognised computer software program. This load will produce both positive and negative effects on the system pressures, resulting in variations in the supplied air volume and pressurisation. It should not be assumed that these changes are detrimental to the total safety of the system performance before first fully analysing their consequences.

Final fan selections should be checked for wind gusts producing velocities with a probability of exceedance of 0.1% to ensure the systems will naturally recover after these adverse effects.

Small volume fans require special consideration. For example a system resistance should not double as a consequence of the addition of the wind load. The use of cowl type inlets and outlets should be used to lessen the effects of wind loading. Components, such as filters, attenuators and ductwork should be increased in size to reduce the system airflow resistance and enable a practical fan selection. This approach will ensure good fan efficiency, reduce generated noise, reduce vibration and retain power requirements within practical limits.





4 SYSTEM DESIGN - AREA SPECIFIC

4.1 PROCESS AND UTILITIES AREAS 4.1.1 Hazardous Area Enclosures

HVAC systems for hazardous areas shall be entirely separate from those serving non-hazardous areas.

Hazardous area enclosures shall not exceed maximum and minimum design temperatures. Typically a maximum temperature of around 35°C is acceptable and where feasible maintained by use of free cooling.

The minimum number of 12 air changes per hour shall be adopted for all hazardous area enclosures. This air change rate should be increased if inadequate to dilute fugitive hydrocarbon emissions.

The system design should include air inlet arrangements that draw 100% fresh-air from a non-hazardous area. For each of the following possible ventilation system arrangements 100% fresh-air is forced or induced into the enclosure and fully exhausted. Recirculation air is not permitted: -

• supply fan and exhaust fan

• supply and natural exhaust

• natural supply and exhaust fan

• Where a hazardous area enclosure is adjacent and/or connected to non-hazardous area enclosures the exhaust ventilation system should be fan assisted to ensure the internal pressure, by design, does not exceed 0 Pa with reference to the local external ambient pressure. In cases not associated with proximity to non-hazardous areas, fan assisted exhaust ventilation may also be required for specific removal of hydrocarbons, fumes or equipment heat.

Internal pressures for hazardous area enclosures not adjacent or connected to non-hazardous area enclosures should be dictated by local ambient conditions with no attempt to provide internal pressure control.

4.1.2 Non-Hazardous Areas Non-hazardous area enclosures should not exceed maximum and minimum design temperatures. The preferred method of cooling is by free cooling and designs should provide adequate airflow and air change rates that meet the pressurisation requirements of 25 Pa – 60 Pa (where required), lighting, electrical equipment, plant equipment, solar and transmission heat gains. Cooling by use of refrigeration plant may be considered where free cooling is insufficient or impractical.

It is accepted that space temperatures may go above the maximum design value for short periods during peak summer outside conditions. This should not deter the use of free cooling.

Heating, where necessary, should be provided by electric heater banks mounted in the AHU or supply ductwork.





The system design should include ventilation arrangements that draw fresh-air from a non-hazardous area. Recirculated air is not preferred but may be permitted for instances where cooling plant is required: -

• supply fan and exhaust fan

• supply fan and natural exhaust

• dedicated independent exhaust systems for fume cupboards, welding bays/booths etc. should be provided as required.

4.2 LIVING QUARTERS HVAC systems should be designed to maintain adequate internal environmental conditions, taking into full account the following criteria: -

• external environmental maximum and minimum design values

• heat gains from personnel, lighting, electrical equipment, plant equipment, solar and transmission

• heat losses due to transmission through external boundaries

During periods in summer or winter, when external conditions exceed the maximum and minimum design values, it is accepted that the design internal temperature may not satisfy the specified limits for short periods of time.

Primary equipment including centralised AHU’s, cooling plant and various ancillary fans should wherever possible be located in a dedicated HVAC plantroom. Selective exhaust-air fans may be located external to the LQ in accessible and unobstructed positions where plantroom location would be impractical eg for laundry exhaust fans the preference is for external location in close proximity to the laundry space.

Supply or exhaust-air fans should not be mounted in ceiling voids. Where this is unavoidable, fan selection is vitally important and should take into serious consideration the consequences of radiated noise through the fan casing in addition to the noise transmitted through the ductwork.

Supply-air Rate The supply-air rate shall be determined by performing three independent calculations – for each separate room or area – that satisfies the criteria listed below. The greatest calculated supply-air rate shall be the adopted design supply-air rate: -

• Maximum cooling load

• Fresh-air requirement

• Number of required air changes per hour





The maximum cooling load depends on the magnitude of heat gains during the maximum design conditions. The fresh-air requirement is to be calculated by estimating the occupancy levels for each room or area and applying a minimum of 8 L /s of fresh-air per person. A minimum number of air changes must also be achieved for each room or area as per the table below. However the actual air change rate may be higher than those shown below; especially when the supply airflow rate is determined by the cooling load or fresh-air requirements.

Room or Area Air Changes per Hour (minimum)

First aid room 6 Laundry 6 Cabins 8 Offices and public areas 10 Cabin toilet spaces 15 Galley 15

The actual air change rate for galleys may be higher than 15 and should be determined by the exhaust-air requirements of galley hoods and canopies. Refer to AS 1668.2 for the method of calculation.

The actual air change rate for laundries should be determined by the drier equipment exhaust requirements in conjunction with the maximum cooling load.

Pressurisation At design wind speed conditions the LQ should be pressurised within a range of 25Pa to 65Pa with reference to the external atmosphere. The optimum pressurisation set point is 50Pa.

Airlocks provided for LQ access doors should not be pressurised or served by the HVAC system.

Consideration must be given to the degree of air leakage from pressurised enclosures, particularly in the refurbishment of existing facilities. Leakage rates of up to 5% on steel plated structures and 10% on clad structures (referenced to 50Pa) may be measured. These figures may be exceeded on existing modules that have not undergone external cladding refurbishment.

Supply-Air Systems The main supply-air system should comprise of a centralised AHU and associated supply duct distribution network. The supply-air system shall be of medium velocity, constant volume, and terminal re-heat type serving the following areas: -

• cabins

• control, equipment and laboratory rooms

• galley, dining and recreation rooms

• offices and public areas

• workshop and locker rooms





The AHU should be provided with a two-stage filter/coalescer to collect dirt, moisture and salt aerosols and also incorporate heating, cooling and humidification equipment as necessary.

The HVAC system may be either a 100% total loss system, or a mixed fresh/return air system. For systems utilising return air, the ratio of return air shall be determined by the quantity of non-returnable air exhausted directly to atmosphere from galley, toilet and general exhaust systems and also the practicality of installing return air ductwork.

Supply-air to all areas should be via constant volume terminal re-heaters to enable individual room temperature control. Ceiling supply-air diffusers should be provided with opposed blade dampers for fine-tune air balancing and also have adjustable air direction capabilities.

Exhaust Systems To prevent cross contamination and maintain hygienic conditions, independent exhaust-air systems must be installed for the type of exhaust categories as listed below: -

• battery rooms

• electrical equipment and electronic rooms

• first aid rooms

• galley

• general (cabins, offices, recreation rooms, corridors)

• laundry

• toilets (cabin toilets, also shower areas)

Small battery rooms containing sealed for life batteries may be served by a general exhaust system although the battery manufacturer’s advice should be sought in each instance.

Galley Systems The galley exhaust system should be designed to induce a proportion of airflow from the dining room (via the servery area) to prevent galley cooking odours entering the dining room.

In order to prevent significant quantities of conditioned air from the dining room being exhausted directly to atmosphere via the galley exhaust system, it is acceptable for up to 70% of the galley supply-air to be introduced by a dedicated galley supply-air system using non-cooled fresh-air. Conditioned supply-air from the centralised AHU should only be introduced via high velocity nozzles to provide spot cooling for personnel working in the galley.

Galley canopies or hoods over all cooking equipment shall be fitted with cleanable grease filters and suitable grease drainage. Provision should also be made for fire detection and fire suppression. Exhaust canopies or hoods should also be installed over dishwashers and any other steam producing equipment located within the galley; and may also be connected to the galley exhaust system.





A dedicated fire damper should be fitted to each ductwork exhaust connection for all galley canopies or hoods. In addition a fire damper must be fitted at every exhaust ductwork penetration through a fire rated barrier and also at the LQ boundary. The fire dampers are to close in accordance with the ESD, F&G systems logic.

All galley exhaust ductwork shall be constructed to meet an A-60 fire rating throughout its entire continuous length.

Supply or exhaust-air ductwork serving spaces not associated with the galley shall not under any circumstances be routed through galley areas or galley ceiling voids.

Laundry Systems Clothes drying machines are a serious potential source of fire. This is primarily due to inadequate filtration systems permitting the build up of lint, unsuitable ductwork design or material selection. Also recirculation air from laundries shall not be permitted to prevent lint contamination. To minimise the risk of fire the following design guidance should be adopted: -

• position filters as close as possible to the drying machine outlet

• install high capacity disposable type filters

• install non-return dampers for each drying machine outlet

• avoid vertical duct runs

• avoid concealed ductwork

• minimise the length of ductwork run

• provide access doors in ductwork for inspection and cleaning

• ensure all ductwork components are accessible and fully serviceable

The preferred arrangement for laundry exhaust systems is to position the exhaust fans externally but close by the laundry space to minimise the ductwork route accordingly. It may be possible to mount the fans at floor level, although for reasons of proximity a high level location over an adjacent external walkway is also acceptable.

All laundry ductwork should be constructed to meet an A-60 fire rating; particularly where circumstances prevent use of design guidance principles as stated above.

Transfer Grilles Transfer grilles should only be provided in toilets since the objective is not to transfer air from cabins into corridors. All corridors and staircases should be positively pressurised in comparison with adjacent areas to assist in maintaining smoke free escape routes.

Temporary LQ/TR's & Office Modules HVAC is usually provided by an independent single or split packaged air conditioning unit to provide supply-air, cooling and or heating to temporary modules. In some instances cooling or heating may not be required and mechanical ventilation may be adequate. Duplication or standby HVAC plant is not necessary.





The HVAC system supply-air should be 100% fresh-air and not be recirculated. Pressurisation should also be provided.

All equipment shall be suitable for the classification of the area in which the module is situated. All ductwork penetrations through the module bulkheads should be installed with a fire damper to ensure the module fire barrier integrity is not compromised.

Toilet or shower units are to be installed with dedicated exhaust fans as required.

It is usually convenient and cost effective to install the HVAC plant on the module roof in spite of possible additional maintenance access requirements.

4.3 DRILLING AND DRILLING UTILITIES AREAS The control of dust and noxious substances in drilling areas will usually require the installation of local exhaust ventilation, which should be discharged in a suitable area that will not affect personnel or be infiltrated by any equipment air intakes.

Shale Shakers and Mud Tanks will require outside supply-air to meet the exhaust-air requirements of the tanks and shakers. Under normal circumstances these requirements will be met by a dedicated supply-air system to provide adequate air distribution to the general space. The exception to this requirement is where the modules are of a semi-open nature allowing air to be drawn in through a variety of openings. Under these circumstances natural supply-air ventilation can be used for make-up air.

These areas should have air change rates that are determined by the air quantity required for the effective extraction of fumes, heat and dust from tanks and shaker enclosures.

Due to the nature of these areas all mechanical ventilation components and equipment should be provided with clear access to perform cleaning and maintenance duties.

4.3.1 Shale Shakers & Cuttings Cleaning Units Shale Shakers and associated drainage troughs should be fully enclosed to ensure capture of fumes at source by exhaust ventilation, thereby preventing unnecessary operator exposure. Enclosures should form an integral part of the Shale Shaker Unit and due consideration should be given to the need for clear access to enable filter screen replacement and maintenance requirements.

Enclosures should be designed so that air velocities through openings ensure complete capture of emitted airborne contaminants. Air velocities in exhaust ductwork, upstream of scrubbing units, should also ensure optimum transportation of airborne contaminants with minimum dropout.

Cuttings Cleaning Units should be provided with exhaust enclosures and ventilation similar to that for shale shaker units.

4.3.2 Mud Tanks Although during the initial design phase some mud tanks may be designated as storage only, (inactive), experience has shown that all mud tanks are likely to contain hydrocarbon bearing liquid, (active), at some stage during the life of the drilling





platform. All tanks should, therefore, be assumed to be active and should be ventilated accordingly.

Tanks should have solid plated covers with minimum penetration for pipework, agitator shafts, valve handles, instrument entries and inspection/access hatches. The void between the covers and mud surface should be constantly purged with ventilation of the entire freeboard. A negative pressure should be achieved within the freeboard space by an imbalance between supply-air entering the void through leakage paths in the cover plate and the ducted exhaust-air system. Precise control over negative pressure is not a requirement of the system design.

Multiple Mud Tanks that are adjacent may be ventilated by a common system, if practical.

Mud Tank enclosures should be designed so that air velocities through openings ensure complete capture of emitted airborne contaminants. Air velocities in exhaust ductwork, upstream of scrubbing units, should also ensure optimum transportation of airborne contaminants with minimum dropout.

4.3.3 Air Scrubbers Air scrubber units, in the form of integrated air washers and plenum settlement chambers, shall be provided for all exhaust ventilation systems serving mud tanks and shale shakers to minimise the discharge of mud and dust particles discharged to atmosphere.

Ductwork between the scrubber and the mud tank or shale shaker should preferably be of circular cross section and be designed for easy disassembly for cleaning. Ductwork should be fitted with maximum sized access doors at each change of direction and installed to fall back towards the mud tank or shale shaker. Any low sections should be fitted with large bore drain valves.

Air scrubbers shall incorporate the following features: -

• air scrubbing sprays

• vane wash sprays

• vane moisture eliminators

• detergent injection (oil based mud)

• drain sump with bolted access

• waste water drain with manometric trap

• all liquid pipework and drain connections

• access doors to spray section and discharge section

Air scrubbers are usually required to operate continuously typically handling air at a peak temperature of 80°C, with normal operation at 40-60°C.

Minimum efficiency with wet mud or dry dust shall be 95% with a particle size range of 5 to 50 microns. The maximum initial (clean) scrubbing unit airflow resistance at the optimum design velocity should not exceed 350Pa.





Detergent should not be added if the effluent is to be discharged to a settling tank. Where used the detergent should be non-foaming, biodegradable and non-clogging.

All construction materials shall be non-combustible and shall not emit smoke or toxic fumes in fire conditions. Construction materials should also be suitable for seawater and chemicals (detergent or mud) likely to be used, with respect to corrosion and erosion.

4.3.4 Cement Units If a drilling cement unit doubles as part of the Well Kill system, its diesel engine, where installed, should be arranged to operate in an emergency. In this case HVAC services should be provided as described for the diesel fire pump (See Section 4.5).

4.4 GAS TURBINE ENCLOSURES Enclosures for gas turbines shall be ventilated in accordance with any specific manufacturer’s requirements and the hazardous area classification in which the unit is located.

Ventilation requirements for all gas turbine enclosures shall fully comply with Woodside Standard W1000MM104 STANDARD: GAS TURBINES: SELECTIONS AND SPECIFICATION.

4.5 EMERGENCY VENTILATION Fire rated enclosures or compartments containing fire pumps, emergency generators or any plant that is required to operate during an emergency, should also be provided with emergency ventilation in addition to normal ventilation requirements.

When diesel engines operate in an emergency, the air required for engine radiator cooling and engine combustion may be provided by a system that forms part of the diesel package and is separate from the normal ventilation system. Where the ambient conditions are considered harsh, it may also be necessary to provide emergency ventilation fans (also separate from the normal ventilation system) to maintain the fire rated enclosure at an acceptable temperature for effective equipment operation.

All fire dampers should be fully integrated with emergency and normal ventilation philosophies. Whilst the diesel engines are not running, normal fire damper logic will apply ie close on either manual or a F&G shutdown signal.

However, in the event of a fire while the diesel engine is running, the fire damper should only close upon rupture of the fire dampers internal frangible bulb or azeotropic tube device.





4.6 ANCILLIARY AREAS

4.6.1 Battery and Charger Rooms Each battery system must be analysed to evaluate the possible extent of noxious or flammable gases that may be released in to the room. The air change rate depends upon the dilution rate of the battery by-products and heat removal from the room. Typically, air change rates for open lead acid batteries will be greater than for totally sealed batteries.

Regulated lead acid batteries are particularly temperature sensitive and are usually specified to operate in the range of 15 to 25°C. Temperatures lower than 15°C may significantly reduce battery power while above 25°C reduce battery life.

Where contamination of the atmosphere is negligible and does not threaten personnel or the integrity of the facility, a general or local exhaust system may be used as the sole means of room ventilation, providing there is no recirculation.

Where contamination levels are deemed to be hazardous and/or environmentally unacceptable, a dedicated exhaust system should be provided. Exhaust-air should be removed at high level (especially over battery racks) to remove lighter than air gases and heat dissipated from batteries and charger units.

Supply-air should be introduced at low level and should maintain battery and charger rooms at a pressure above adjacent hazardous areas (or below in the case of adjacent non-hazardous areas).

If the batteries are known to produce hazardous levels of explosive gas during boost charging, then battery charger operation should be interlocked to stop charging upon loss or failure of the exhaust fan.

4.6.2 Laboratories Sufficient supply-air required to maintain room pressurisation and adequate internal environmental conditions may be provided by a dedicated or centralised HVAC system.

All supply-air shall be fully exhausted by a fume cupboard and/or dedicated exhaust system. Supply-air shall not be recirculated.

Fume cupboards shall incorporate a dedicated exhaust fan and associated ductwork. They shall exhaust directly to atmosphere with discharge cowls located to avoid personnel contact with exhaust fumes. Recirculation type fume cupboards shall not be permitted.





4.6.3 Chemical Storage Rooms Supply-air to chemical storage rooms shall be continually purged and draw 100% outside fresh-air from a non-hazardous area ie total loss system.

Duty/standby fans should be provided in line with the standby philosophy and be provided with automatic changeover. Fan controls shall be integrated with the overall ESD, F&G and safety systems.

4.6.4 Purging Equipment Supply-air to specific electrical enclosures, plant and components that require to be continually purged shall draw 100% outside fresh-air from a non-hazardous area ie total loss system.

Duty/standby fans should be provided in line with the standby philosophy and be provided with automatic changeover. Fan controls shall be integrated with the into the control system of the equipment being served and into the overall ESD, F&G and safety systems.

Purge air supply to equipment required to run in an emergency should be connected to an emergency power supply.

5 INSTALLATION, COMMISSIONING AND DOCUMENTATION

Installation and commissioning shall be carried out as per DEP 31.76.10.11-Gen.

In particular the Contractor shall submit for review and approval the following: • a functional description of the testing and balancing procedure to be

followed for each item of major plant and for each air, water, electrical and control system;

• equipment schedules for all major items of plant showing the design requirements and supplied capacities cross-referenced to the drawings;

• calibration certificates for test equipment;

• test and balance forms for all systems and components;

• control system logic diagrams and test flow charts together with test results;

• pressure test results for all installed systems;

• electrical circuit continuity and earthing test results;

• electrical insulation test results;

• preliminary as-built drawings, operation and maintenance manuals, certificates and factory test data.





6 REFERENCES

LEGISLATION, ASSOCIATED GUIDANCE AND APPROVED CODES OF PRACTICE ABS American Bureau of Shipping

AMSA Australian Maritime Safety Act

Lloyd’s Lloyd’s Register of Shipping

SOLAS International Maritime Organisation – Safety of Life at Sea SI 1992 No. 2885 The Offshore Installations (Safety Case Regulations) 1992

SI 1995 No. 743 Offshore Installations (Prevention of Fire and Explosion, and Emergency Response) Regulations and Approved Code of Practice

SI 1994 No. 3246 Control of Substances Hazardous to Health Regulations and General COSHH Approved Code of Practice

INTERNATIONAL STANDARDS ISO 15 138 (Draft) Petroleum and Natural Gas Industries – Offshore Production

Installations – Heating, Ventilation and Air-conditioning

Institute of Petroleum Area Classification for Petroleum Industries, Model Code of Safe Practice, Part 15

AUSTRALIAN STANDARDS AS 1167 AS 1167.1

Welding and brazing – Filer metals Part 1: Filler metal for brazing and braze welding

AS 1210 Pressure vessels AS 1271 Safety valves, other valves, liquid level gauges, and other

fittings for boilers and unfired pressure vessels

AS 1324 AS 1324.1 AS 1324.2

Air filters for use in general ventilation and air conditioning Part 1 : Application, performance and construction Part 2 : Methods of test

AS 1345 Identification of the contents of pipes, conduits and ducts

AS 1530 AS 1530.1 AS 1530.2 AS 1530.3

Methods of fire tests for building materials, components and structures Part 1: Combustibility test for materials Part 2: Test for flammability of materials Part 3: Simultaneous determination of ignitability, flame propagation, heat release and smoke release

AS 1571 Copper – Seamless tubes for air conditioning and refrigeration AS/NZS 1668.1 AS 1668.2 AS 1668.2 Supp1

The use of mechanical ventilation and air conditioning in buildings Part 1: Fire and smoke control in multi-compartment buildings The use of mechanical ventilation and air conditioning in buildings Part 2: Mechanical ventilation for acceptable indoor-air quality The use of mechanical ventilation and air conditioning in





buildings Part 2: Mechanical ventilation for acceptable indoor-air quality – Commentary (Supplement to AS 1668.2)

AS/NZS 1677 AS/NZS 1677.1

Refrigerating systems Part 1: Refrigerant classification

AS 1921 Air conditioning and ventilation in ships – Cabins and living spaces of merchant ships

AS 1925 Air conditioning and ventilation in ships – machinery control rooms of merchant ships

AS 1939 Degrees of protection provided by enclosures for electrical equipment (IP Code)

AS 2107 Acoustics – Recommended design sound levels and reverberation times for building interiors

AS 2129 Flanges for pipes, valves and fittings

AS 2254 Acoustics – Recommended noise levels for various areas of occupancy in vessels and offshore mobile platforms

AS 2380 Electrical equipment for explosive atmospheres – Explosion protection techniques

AS 2381 AS 2381.1

Electrical equipment for explosive atmospheres – Selection, installation, and maintenance Part 1: General requirements

AS 2430 AS 2430.1

Classification of hazardous areas Part 1: Explosive gas atmospheres

AS 2936 SAA Fan Test Code

AS 2971 Serially produced pressure vessels

AS 3000 SAA Wiring Rules

AS 3102 Approval and test specification for electric duct heaters

AS 3439 Low voltage switchgear and controlgear assemblies

AS 3666. 1&2&3 Air handling and water systems of buildings

AS 4254 Ductwork for air handling systems in buildings





INDUSTRY STANDARDS AIRAH Design Guides

ASHRAE Fundamental Handbooks, Standards & Guidelines

CIBSE Design Guides

SAA HB40 SAA HB40.1

The Australian Refrigeration and Air Conditioning Code of Good Practice Part 1: Reduction of emissions of fluorocarbon refrigerants in commercial and industrial refrigeration and air conditioning applications

SMACNA Sheet Metal and Air Conditioning Contractors National Association – HVAC Duct Construction Standards for Metal and Flexible Ducts

SMACNA Sheet Metal and Air Conditioning Contractors National Association – Ductwork Leakage Testing

SHELL DESIGN & ENGINEERING PRACTICES DEP 37.17.10.11 – Gen.

Design of Offshore Temporary Refuges

WEL STANDARDS W1000SE025 Standard: Electrical Engineering Design

W1000SE002 Standard: Low Voltage Switch Gear

W1000ME009 Guideline: Electrical Requirements for Package Equipment

W1000SE005 Standard: HV and LV Electric Machines, Cage Induction Type

W1000SJ010 Standard: Instrument Installation

W1000MM103 Standard: Pumps, Selection and Specification

W1000MM104 Standard: Gas Turbines, Selections and Specification

http://supplierinfo.woodside.com.au/Link/?Loc=LO&Lg=N&dmsn=2687494











7 APPENDICES

APPENDIX

AIR HANDLING UNITS 1

CONSTANT VOLUME TERMINAL REHEAT UNITS 2

COOLING PLANT 3

COWLS AND WEATHER LOUVRES 4

DUCTWORK 5

FANS 6

FILTERS AND COALESCERS 7

FIRE DAMPERS 8

GENERAL DAMPERS 9

GRILLES AND DIFFUSERS 10

HEATER BANKS 11

HUMIDIFIERS 12

PUMPS 13

SOUND ATTENUATORS 14

DATA SHEETS 15





7.1 APPENDIX 1 AIR HANDLING UNITS General The AHU shall provide a robust housing for major mechanical air handling equipment and associated components, that will: -

• protect internal equipment from mechanical damage and corrosion

• enable straightforward pre-delivery performance testing

• improve accessibility to all components for service and maintenance

• minimise heat loss, noise break-out and eliminate external condensation or cold bridging by use of thermal/acoustic insulation.

The design of both externally and internally located AHU’s will be similar, with the exception that external units should be fitted with a pitched roof to prevent water/corrosive fluids pooling on the top of the unit, particularly between any panel section joints.

Most AHU’s will be located internally within a dedicated HVAC plantroom and not subject to harsh environmental conditions once installed. However whether located internally or externally all AHU’s shall be fabricated from stainless steel type 316 and have a high build quality in order to resist damage and corrosion while in the fabrication yard, during shipping and when put into operation.

All major equipment items as determined by the HVAC design should be fixed or housed in such a manner that permits complete withdrawal.

AHU Housing The AHU should where possible be designed to have a constant width and height and also avoid large roof spans. The length and overall dimensions should be kept to a practical minimum to maintain adequate access space for maintenance and withdrawal of internal equipment, while also ensuring that the air velocity across filters, heater bank and cooling coil face areas does not exceed 2.5m/s.

The AHU housing shall consist of double skinned insulated wall, ceiling and floor panels fixed to a rigid main sectional support frame. The sectional support frame shall be constructed from stainless steel type 316 angle or other section of not less than 3mm thickness. The support frame shall be fully welded throughout.

The outer skin for wall, ceiling and floor panels shall be a minimum of 1.6mm thick stainless steel type 316 sheet while the inner skin of 1mm thick respectively.

Panels shall be insulated with fire resistant semi-rigid glasswool having a minimum thickness of 50mm. The insulation shall be fire retardant and have a thermal conductivity of not more than 0.035 W/m K at 20°C and a minimum density of 48 kg/m³. When tested in accordance with AS 1530 part 3 the insulation shall exhibit the following characteristics: -

• ignitability index 0

• spread of flame index 0

• heat evolved index 0

• smoke developed index 0 – 1





Access doors shall be provided for inspection, service and maintenance purposes. Access doors shall generally be of the same construction as the wall panels and be fitted with adequate hinges, securing latches and airtight door seals. The entire AHU shall be made both airtight and water tight between all panel joints, seams and all other mating faces to maintain the integrity of the thermal and vapour barrier using neoprene gaskets and mastic sealant. All pop rivets shall be of the stainless steel blind type and further plugged with mastic sealant. Base Frame A single base frame or skid frame shall be fitted to provide a rigid support for the entire AHU assembly. The skid shall be certified as a lifting frame and capable of supporting the whole unit during lifting. The skid shall also include lifting lugs suitable for cranage and rigging gear. The frame will typically be constructed of hot dipped galvanised steel.

Filters Filters shall be easily accessible for maintenance and cleaning while the AHU remains operational. The preferred arrangement is for a man-size access door into a dedicated filter access compartment.

Fans AHU’s should incorporate supply air fans of the "draw-through" type to ensure the airflow across filters, heater bank and cooling coil face areas is uniformly distributed.

Fan and motor assemblies shall be vibration isolated from the AHU by mounting them on dedicated frames with anti-vibration mountings. Fan and motor drive assemblies shall be fitted with accessible and removable guards for replacement and tensioning of belts.

For duty and standby fan motor assemblies separate compartments should be provided to permit servicing, maintenance or removal of a fan motor whilst the other fan motor remains operational. Duty and standby fan arrangements shall each be fitted with automatic shut-off dampers to prevent short cycling of air through the non-operating fan.

Cooling Coils and Heater Banks Internal partitions shall be installed to prevent the air stream from bypassing the heat exchanger contact surfaces. Internal partitions shall be thermally insulated using fire retardant materials as specified for the AHU housing.

Internal partitions shall be used to position cooling coil headers and associated local control valves outside the air stream but within the AHU housing. Terminal boxes and associated safety devices for electric heater banks shall also be positioned in the same manner.

Cooling coil inlet and outlet pipework connections shall protrude through the AHU housing wall via insulated pipe penetrations for hook up on site.

Cooling Coil Drip Trays Each cooling coil shall be fitted with a condensate drip tray constructed from continuous stainless steel type 316 sheet of not less than 2mm thickness. All corner





joints shall be continuously welded. The minimum height at any given point of the drip tray shall not be less than 75mm. The drip tray shall also be insulated to prevent surface condensation run-off inside the AHU.

For AHU’s installed on board floating facilities each condensate drip tray shall be fitted with two equal size drain points fitted at opposite ends of the tray to allow for any listing and rolling movement. In this instance the drip tray shall be pitched from the centre point towards both ends.

Each drain point shall be connected to a manometric trap of sufficient depth to provide a water seal that withstands the fan static pressures. The manometric trap shall be installed in an accessible location on the external surface of the AHU.

Steam Humidifiers Where humidifiers are fitted, the preference is for the steam generator to be contained within a compartment of the AHU but outside of the air stream.

Where possible the steam injection point should be positioned upstream of the fan inlet where good mixing is assured.

The floor of the AHU down stream of the steam injection point should incorporate a fall to a drain point in the event of water carry over from any steam that may condense.

Glass observation ports should be fitted down stream of humidifiers to verify their performance. Internal AHU lighting shall be fitted when observation ports are installed.

Volume Control Dampers It may be feasible for the fresh-air and return-air volume control dampers to form an integral part of the AHU. Provision for damper access and adjustment shall be required in this instance.

Ductwork Connections The AHU shall be provided with flanges for ductwork connection to the air inlet, supply-air and return air as required. The flanges shall be constructed from fully welded stainless steel type 316 angle and pre-drilled in accordance with the drilling detail for the connecting ductwork.

Access The design of the AHU should provide adequate access for inspection, service, maintenance and withdrawal of all equipment items.

For AHU’s with a clear internal height of 1500mm or more, man-size hinged access doors shall be provided for walk-in access compartments for all equipment and components. Where possible these compartments should serve adjacent equipment items.

For AHU’s with a clear internal height of less than 1500mm, hinged access doors and/or side and top lift-off access panels may be provided.

In all cases, lift-off access panels may be provided to enable access to individual components such as control valves or electrical devices where inaccessible by any other means.





Electrical All electrical equipment and associated controls shall be selected in compliance with the hazardous area classification in which the AHU is located.

Ex'e IP65 rated bulkhead light fittings should be located inside each walk-in type access compartment. Switches for these lights should be positioned on the external face of the AHU and be clearly labelled to identify use.

All electrical equipment shall be fully earth bonded. Earthing bosses shall be fitted to the skid frame to provide for external earth bonding. A minimum of two stainless steel type 316 earthing bosses shall be welded to the skid frame and be tapped for an M10 stainless steel stud complete with nuts and washers.

Also refer to the requirements of the following Woodside Standard: -

W1000SE025 STANDARD : ELECTRICAL ENGINEERING DESIGN

http://dmslink/link/?dmsn=2687494&edit=true





7.2 APPENDIX 2 CONSTANT VOLUME TERMINAL REHEAT UNITS

General Constant volume terminal reheat units shall be fitted into supply-air branch ductwork sections upstream of supply-air registers serving a single zone or room for non-hazardous enclosures only. The units shall be designed to provide a constant airflow quantity, adequate sound attenuation and accurate temperature control.

Each unit should contain the following three basic components: -

• constant volume regulator – a self actuating mechanical device providing a non fluctuating constant airflow quantity

• sound attenuator – acoustic insulation that reduces duct borne noise being transmitted through the unit and into the room

• electric air heater – during summer or winter used to trim the supply-air temperature according to the room thermostat set point

• The air heater may be excluded when provision for heating is not required or alternative methods of heating are employed.

Constant Volume Regulator The regulator shall be designed as a self-actuating device, the sole motive force being supplied by the airflow through the unit. Units should be selected at the mid-point of the unit’s regulator design range.

The regulator set point shall be adjusted to ensure that the airflow quantity is maintained within ±5% of the design volume requirement. The set point should be manually adjustable without the need for specialised tools. The air velocity should normally range from a minimum of 2.5m/s up to a maximum 5.0m/s.

Plastic or rubber components in the form of diaphragms or bellows shall not be permitted as part of the constant volume regulator.

Sound Attenuator The dynamic insertion loss must be equal or greater in all frequency bands than the required value in accordance with the HVAC design noise calculations. Noise generated by the unit itself should also be considered in determination of a suitable unit.

Acoustic media material shall be non-hygroscopic and fire retardant. The attenuator material shall be secured by perforated stainless seel steel sheet and provide adequate strength, minimal airflow resistance and air turbulence. A polyester lining shall be fitted between the acoustic media material and the perforated sheet to prevent any media fibres migrating into the airstream.





Electric Air Heater Heaters shall comply with AS/NZS 3102 and be type tested with a safety clearance certificate as a minimum.

The electric heater shall be suitable for continuous and intermittent operation, and should also provide minimal air turbulence and airflow resistance.

All heaters shall have a maximum rating of 2.4kW when connected to a single phase supply or 2kW per phase when connected to a three phase supply. For three phase supplies, elements shall be arranged to ensure the out of balance load across each phase is not greater than 2%.

The heater elements shall be mounted on a support plate complete with an electrical termination box. The degree of protection required for the termination box shall be a minimum of IP56.

The heater assembly shall be designed for insertion through a rectangular hole cut into the side of the unit whereby the termination box remains clear of the airstream. The handing of the cutout shall be determined by the ductwork layout and access for servicing and maintenance to ensure complete withdrawal of the heater assembly is made possible.

All elements shall be provided with element supports to prevent vibration and sagging. Where elements do not match the cross sectional face area of the unit’s internal dimensions, the space beyond the elements shall be fitted with 316 type perforated steel sheet of 50% open area.

Elements shall have a maximum surface temperature rating of 200°C (T3) when operating in still air conditions. Under normal operating airflow conditions elements shall not exceed a surface temperature of 135°C (T4).

Heating elements shall be constructed from nickel-chrome resistance wire contained within magnesium oxide, all encased within an Incoloy 800 sheath. Elements may be provided with fins to increase the heat exchange surface but only where full compliance with the surface temperature requirements is strictly met.

The unit casing shall be thermally insulated for a distance of not less than 250mm upstream and downstream from the heater elements. Thermal insulation shall be non-combustible and have a coefficient of heat transfer not greater than 30 W/m²K at 100°C.

The unit shall also be fitted with devices to satisfy both of the following requirements and safeguard against overheating under abnormal operating conditions: -

• a thermal cut-out device or a supply-air failure switch to interrupt the power supply to the heater elements upon loss of the supply airflow

• a manual reset thermal cut out device to monitor the air temperature in the immediate vicinity of the heater elements - set to trip at 120°C and interrupt the power supply to the heater elements





Electrical All electrical equipment and associated controls shall be selected in compliance with the hazardous area classification in which the unit is located.

All electrical equipment shall be fully earth bonded. A main earthing post or terminal strip shall be provided in each terminal box for the earth core of each incoming and outgoing cable.

An earthing boss shall be fitted to all casings fabricated from stainless steel. A stainless steel type 316 earthing boss shall be welded to the casing to provide for external earth bonding and be tapped for an M10 stainless steel stud complete with nuts and washers.

Also refer to the requirements of the following Woodside Standards: -

• W1000ME009 GUIDELINE: ELECTRICAL REQUIREMENTS FOR PACKAGE EQUIPMENT W1000SE025 STANDARD : ELECTRICAL ENGINEERING DESIGN







7.3 APPENDIX 3 COOLING PLANT

Refrigerant Type Refrigeration systems associated with HVAC systems have traditionally used R22 as the refrigerant. However, R22 is no longer acceptable for new facilities. Acceptable refrigerants are R407C or R410A for package units and R134A for chillers.

General Cooling plant should be provided by a centralised or packaged refrigeration system in accordance with AS 1677 Refrigerating Systems.

Centralised refrigeration systems may be of the CHW type or DX type depending on the cooling capacity requirement, practicality and layout. In all cases these types of refrigeration system should operate as part of an integrated HVAC system and be automatically controlled by the HVAC control system.

Packaged refrigeration systems shall be supplied complete with all necessary equipment and componentry. The package may operate independently or as part of an integrated HVAC system.

Each refrigeration system shall be sized with sufficient cooling capacity and be capable of continuous operation during full cooling load requirements and intermittent operation with long idle periods during low cooling load requirements.

Manufacturers standard refrigeration products are preferred when the plant is to be located in a non-hazardous area, as provided by installing refrigeration plant within an enclosed dedicated HVAC plantroom.

Customised or purpose built refrigeration plant is not preferred but may be unavoidable where plant location must comply with a hazardous area classification. Alternatively it may be possible to modify the electrical cabling and componentry of a manufacturers standard product to comply with the hazardous area classification.

Where refrigeration equipment is located externally it shall be constructed from suitable materials and include protective coatings as required for operation in a marine environment.

Refrigeration plant shall be supplied with all necessary controls and components of refrigeration industrial quality. Each refrigeration circuit should incorporate the following components as a minimum: -

• high pressure cut-out switch – manual reset

• low pressure cut-out switch

• oil differential pressure switch

• gauge panel with suction, discharge and oil pressure gauges

• compressor crankcase heater

• compressor suction and discharge service valves





• refrigerant liquid line filter driers and sight glass

Compressors Open-drive, semi hermetic or hermetic compressors may be used providing the electrical rating complies with the power supply voltage and the hazardous area classification in which it is located. Reciprocating, screw and scroll compressors are equally acceptable.

• Reciprocating No fixed capacity limit by utilising multiple compressors sets in conjunction with compressor capacity control. Reciprocating compressors can be adapted to any system configuration and range from small hermetic to medium semi-hermetic or large open-drive capacity types.

• Screw/Rotary Normally selected for capacities in excess of 160kW they include multi-step compressor capacity control and are preferred to reciprocating compressors where large cooling capacities are required. These compressors are usually supplied as part of a self contained chiller set.

• Scroll When utilising multiple compressors technically there is no fixed capacity although these compressor types are fully hermetic and should only be utilised for single cooling zones with capacities up to 60 kW.

Water Cooled Condensers Condensers should be water-cooled when the practicality and availability of providing seawater or tempered water cooling to the condenser location is feasible.

Water-cooled condensers are normally mounted on the common base frame of a self-contained CHW type chiller set or DX condensing unit. Condensers shall be of the shell and tube type fitted with removable water boxes at each end for inspection and cleaning of the waterside tubes.

Sized accordingly, water-cooled condensers may also serve as the refrigeration circuit liquid receiver providing they have sufficient volumetric capacity to pump down the system refrigerant charge, a pressure safety valve and all necessary refrigeration service valves.

Water-cooled condensers shall be manufactured with seamless titanium or 90/10 cupro-nickel alloy tubes and tube end plates as a minimum. The removable water boxes should be manufactured from aluminium bronze, however where acceptable by the project specification they may be constructed from carbon steel providing all steel surfaces exposed to cooling water are treated with a suitable protective coating such as an approved glass flake resin or ceramic compound.

All water-cooled condensers shall be fitted with sacrificial anodes suitable for protection against electrolytic corrosion.

Water-cooled condensers are pressure vessels and shall be manufactured in accordance with AS 1210 for unfired pressure vessels. The waterside of the





condenser shall be hydrostatically tested at 1.5 times the working pressure but not less than 1550 kPa(g) while the refrigeration side shall be pressure tested to a minimum of 2100 kPa(g).

Air Cooled Condensers Condensers should be air-cooled when the practicality, availability of external space and the local environmental conditions are appropriate. For refrigeration systems that are required to operate during an emergency the condenser shall be of the air-cooled type in every case.

Air-cooled condensers can be supplied for most capacity requirements, however for capacities above 160kW the units are usually too bulky and require impractical space for mounting. Consequently their use for larger capacities is discouraged.

The air-cooled condenser location should be selected to provide unrestricted airflow across the condenser, avoid local heat sources and prevent the condenser fans from short-cycling air across the condenser coil.

Manufacturers standard air-cooled condenser products are not suitable for saliferous marine environments or hazardous areas. As such, all air-cooled condensers shall be of the custom built type.

Condenser casings shall be fully weatherproof and constructed from stainless steel type 316 sheet having a minimum thickness of 1.6mm. The casing shall house the condenser heat exchanger coil and multiple condenser fans each fitted with stainless steel fan guards. Legs or mounting brackets shall be also be constructed from stainless steel type 316 folded sheet or section having a minimum thickness of 3mm.

The heat exchanger coil shall be constructed from copper tubes with copper fins and be coated with a protective finish such as electro-tinning. Alternatively the manufacturers own protective finish may be considered if specifically developed or suited for marine environments.

Condenser fan motors shall be direct drive and suitable for the hazardous area classification in which they are located. As a minimum requirement all fan motors and associated electrical components shall be Ex’e rated. All fan motors shall be pre-wired to a common junction box to provide a single point termination for incoming cables when installed on site. All cable wires shall be crimped and numbered according to the electrical termination diagram.

Fan motor resilient mountings should be selected to provide not less than 95% isolation of all frequencies transmitted to the condenser supporting structure.

Fan noise levels should be limited to 80 dBA at 1 metre away from the condenser casing especially where personnel may be continually exposed to the condenser.

Evaporators - CHW Shell and Tube Type CHW shell and tube evaporators are normally mounted on the common base frame of a self contained chiller set and serves to refrigerate or chill the water that is circulated through the closed loop CHW piping system.

Evaporators shall be fitted with removable water box covers at each end for inspection and cleaning of the waterside tubes.





Evaporators shall be manufactured with seamless copper tubes or 90/10 cupro-nickel alloy tubes and tube end plates. The removable water boxes should be manufactured from aluminium bronze, however where acceptable by the project specification they may be constructed from carbon steel providing all steel surfaces exposed to CHW are treated with a suitable protective coating such as an approved glass flake resin or ceramic compound.

CHW shell and tube evaporators are pressure vessels and shall be manufactured in accordance with AS 1210 for unfired pressure vessels. The waterside of the evaporator shall be hydrostatically tested at 1.5 times the working pressure but not less than 1550 kPa(g) while the refrigeration side shall be pressure tested to a minimum of 2100 kPa(g).

Evaporators - DX Cooling Coil Type DX evaporator cooling coils are normally mounted in the supply-airstream of AHU’s or supplied as an integral part of a packaged refrigeration unit.

Cooling coils shall be constructed from copper tubes with copper fins and shall be coated with a suitable finish such as that provided by electro-tinning to provide adequate protection in a marine environment. Alternatively the manufacturers own protective finish may be considered if specifically developed or suited for marine environments.

The perimeter holding-frame and tube end sheets shall be constructed from brass. The holding-frame shall be constructed for flange mounting allowing the evaporator coil to be easily removable.

Cooling coils shall have a face velocity of not more than 2.5 m/s and fin spacing not exceeding 2.5mm. Evaporators shall be factory pressure tested at 2000 kPag(g) in accordance with the manufacturers test procedures.

Cooling coils shall be provided with a condensate drip tray constructed from continuous stainless steel type 316 sheet of not less than 2mm thickness. All corner joints shall be continuously welded. The minimum height at any given point of the drip tray shall not be less than 75mm. The drip tray shall also be insulated to prevent surface condensation run-off.

CHW Cooling Coils CHW cooling coils are normally mounted in the supply airstream of AHU’s, supply-air ductwork or fan coil units.

CHW cooling coils mounted in AHU’s shall be constructed in the same manner as for DX evaporator cooling coils.

Controls Refrigeration systems shall be complete with a control panel of the manufacturers standard range in the case of packaged systems.

Where the panel must comply with a hazardous area classification or project specific electrical control gear, starting gear and wiring requirements, then the panel shall be of the custom built type.

In each case the control panel should contain all or part of the following componentry: -





• mains isolator

• crankcase heater Isolator

• compressor motor MCB’s

• condenser fan motor MCB’s

• supply/evaporator fan motor MCB’s

• control circuit MCB

• compressor motor starters and overloads

• condenser fan motor starters and overloads

• supply/evaporator fan motor starters and overloads

• overload protection against single phasing

• compressor capacity controls

• automatic temperature controls and indication

• automatic pump-down control

• anti short cycle timer device

• on-off control switch

• duty selector switches

• reset pushbuttons

• emergency stop pushbutton

• hours run meter for each compressor

• equipment running lamps

• equipment stopped lamps

• equipment fault lamps

• lamp test pushbutton

• volt free alarm contacts for group alarm indication

• volt free contacts for equipment status and monitoring

Temperature control shall be electronic using PID controllers and associated sensors valves and actuators.

Provision for interconnection and interlocking with the main HVAC control panel shall be incorporated into the control philosophy.

The refrigeration system should also be fitted with all or part of the following indication and control components that are normally fitted external to the control panel: -

• suction pressure gauges

• discharge pressure gauges

• oil pressure gauge





• condenser water temperature gauges

• evaporator water temperature gauges

• low pressure cut-out switch

• high pressure cut-out switch – manual reset type

• head pressure control switches

• oil differential pressure switch

• condenser water flow switch

Electrical All electrical equipment and associated controls shall be selected in compliance with the hazardous area classification in which the cooling plant is located.

All electrical equipment shall be fully earth bonded. A main earthing post or terminal strip shall be provided in each control panel and terminal box for the earth core of each incoming and outgoing cable.

Earthing bosses shall be fitted to equipment skid frames to provide for external earth bonding. A minimum of two stainless steel type 316 earthing bosses shall be welded to skid frames and be tapped for an M10 stainless steel stud complete with nuts and washers.


• W1000SE002 STANDARD - LOW VOLTAGE SWITCHGEAR

• W1000ME009 GUIDELINE: ELECTRICAL REQUIREMENTS FOR PACKAGE EQUIPMENT

• W1000SE025 STANDARD : ELECTRICAL ENGINEERING DESIGN








7.4 APPENDIX 4 COWLS AND WEATHER LOUVRES

General Air intakes for all HVAC systems shall be protected by the installation of high efficiency weather louvres for protection from water ingress during adverse wind and weather conditions. All air intakes shall also be fitted with bird mesh screens to prevent large particles or debris from entering the HVAC system.

Exhaust outlets may include similar louvres and screens having a lower efficiency.

Pressure relief ducts or openings should not be fitted with louvres but should have cowls or swan necks including bird mesh screens to reduce the effects of adverse weather conditions.

Cowls or swan necks including bird mesh screen may also be used on intakes or exhausts where additional benefit over louvres is demonstrated.

Bird mesh screens should be located for ease of access and cleaning. Access doors may be required to enable the screens to be adequately maintained on larger intakes or exhausts. Adequate support structures should be included where required.

Cowls and weathers louvres shall be constructed from a minimum of 2mm stainless steel type 316 sheet and be of fully welded construction. Bird mesh screen shall be constructed from stainless steel wire mesh.

Performance Intake louvres shall have a high water removal capability with a low airflow resistance. The airflow resistance across the louvre should not exceed 100Pa.

Intake louvres should also be capable of ensuring no water carryover for a loading of 100 l/m² where moisture droplets are greater than 30 microns diameter. The louvres and components are to be self-draining.

Louvres should also provide minimal changes in performance with varying wind directions. Typical performance efficiencies at 90° to the wind for a wind speed of 27m/s are: -

• 30 microns 100%

• 25 microns 99.5%

• 20 microns - 99%

• 15 Microns 94%





7.5 APPENDIX 5 DUCTWORK Design All ductwork shall be designed, manufactured and installed in accordance with the following standards: - AS 4254 Ductwork for air-handling systems in buildings SMACNA Duct Construction Standards for Metal and Flexible Ducts

Ductwork should be sized for a pressure gradient of 1 Pa per meter length. Where medium to high velocity ductwork is unavoidable the maximum permitted pressure gradient shall be 8 Pa per meter length.

Main branches of ductwork systems should be sized to suit the following maximum velocities: -

• supply – 11 m/s

• return – 6 m/s

• exhaust – 6 m/s All ductwork systems shall be designed and constructed to withstand a positive static pressure limit of 2000 Pa or a negative static pressure limit of 750 Pa. The maximum air leakage limit shall be 0.003 x p0.65 L/s/m² of duct surface area, where p is the differential pressure in Pa.

Air velocities that exceed the recommended maximums should be avoided to ensure duct generated noise levels and duct resistances are kept to a minimal.

Ductwork systems should be designed to include volume control dampers at each main branch duct to allow for a fully proportional system air balance. All ductwork systems should also be sized to be self-balancing wherever possible.

Ductwork Materials All ductwork located externally shall be constructed from fully welded stainless steel type 316 sheet. All stainless steel welds shall be cleaned and passivated to ensure maximum corrosion protection.

• External Ductwork

• 2-3mm thick stainless steel type 316 sheet

• Internal Ductwork – Production and Drilling Modules 2mm thick stainless steel type 316 sheet, fully welded

• Internal Ductwork – LQ/General 1.6mm stainless steel sheet

• Internal Ductwork – Humid or Corrosive Air Systems Stainless steel type 316 sheet, fully welded, thickness as follows Fresh-air intakes up to air filters 2mm Galley exhaust 2mm Laundry exhaust 1.6mm Battery room exhaust 1.6mm Fume cupboard exhaust 1.6mm





Flexible Ductwork Flexible ductwork shall not be used except for final connections in the LQ between constant volume terminal boxes and their associated ceiling diffusers. Each flexible connection shall be limited to a maximum length of 800mm. Flexible connections shall be fixed to ductwork and ceiling diffuser spigots using worm-drive clamps.

Flexible ductwork connections for fan inlets or outlets shall be made using non combustible heavy industrial type flexible material, factory fitted with flanges to suit the fan and corresponding ductwork. The flexible fan connection shall be capable of withstanding the fan operating pressure range.

Insulation All supply-air ductwork downstream of cooling coils shall be fully insulated complete with a vapour barrier to provide thermal conservation and anti-condensation protection.

Internal circular supply-air ductwork within the LQ may be of the pre-insulated type providing the insulation material meets the requirements of AS 1530 part 3 (refer below).

Fresh-air ductwork upstream of cooling coils, internally located return air ductwork and all types of exhaust air ductwork shall not require insulation.

Ductwork fitted externally to enclosed spaces shall have a minimum insulation thickness of 50mm. The insulation shall be fitted to the internal walls of the duct.

Ductwork fitted internally within enclosed spaces shall have a minimum insulation thickness of 25mm. The insulation may be fitted to the inner or outer walls of the duct.

Insulation material fitted to inner duct walls shall be of semi-rigid mineral wool with a factory applied matt-faced liner. Insulation shall be fixed to the duct walls using non-flammable adhesive and be mechanically secured and covered by an inner case of perforated steel sheet.

Insulation material fitted to outer duct walls shall be of semi-rigid mineral wool with a factory applied outer foil face. The insulation shall be fixed to the duct wall using non-flammable adhesive and be mechanically secured with retaining pins and chicken wire mesh.

All insulation shall have a thermal conductivity of not more than 0.035 W/m K at 20°C and a minimum density of 48 kg/m³. When tested in accordance with AS 1530 part 3 the insulation shall exhibit the following characteristics: -

• ignitability index 0

• spread of flame index 0

• heat evolved index 0

• smoke developed index 0 – 1

Sealing and Fasteners All flanged ductwork joints shall be sealed using neoprene gasket material between the flange faces.

Appropriate weather, fire or pressurisation gasket sealing materials shall be provided wherever ductwork penetrations pass through bulkheads, floors or roofs.





All ductwork fasteners (nuts, bolts, set screws, locknuts, washers) shall be of stainless steel for stainless ductwork and of carbon steel protected by electro-galvanising or cadmium plating for galvanised ductwork. All self-tapping screws shall be of stainless steel.

Dissimilar metal contact shall be avoided or isolated where unpreventable. All new ductwork pieces shall be continuity bonded throughout the continuous length of each ductwork run.

Hangers, Brackets and Supports All ductwork shall be properly and substantially supported by hangers, brackets or supports designed to suit the requirement of each point. External hangers and supports and those exposed to external conditions shall be designed to withstand wind loads in addition to static loads.

The maximum allowable distance between rectangular ductwork supports shall be as follows: -

Longest Side of Duct (mm) Maximum Support Spacing (mm) 0 – 800 1800 801 – 1200 2400 1201 – 2500 3600

The maximum allowable distance between internal circular ductwork supports shall be 1800 mm for all sizes of circular ductwork.

Suitable insulation or isolation shall be provided to prevent contact between support hangers and dissimilar metals.

Maintenance Access Galley and laundry exhaust systems shall incorporate sufficient access to permit inner ductwork and component cleaning for the complete ductwork route.

Wherever practicable hinged doors having 500 x 500mm clear openings should be provided to give access to duct mounted equipment and fire dampers to enable routine inspection, service and maintenance to be performed.

Exhaust systems serving mud tanks and shale shakers should be provided with access for frequent cleaning of all components, equipment and the complete ducting system. Access platforms and/or walkways may be necessary.

Test Holes Test holes provided in the ductwork for insertion of airflow or temperature instruments shall be fitted with non-combustible removable plugs for commissioning purposes. Plug locations should be clearly labelled "VENTILATION TEST HOLE" or similar.

Test holes shall not be permitted in fire rated ductwork or flexible ductwork and fan flexible connections.





7.6 APPENDIX 6 FANS

General Fans should be driven by an electric motor either directly or in conjunction with a drive belt assembly. Electric fan motors shall be suitable for the hazardous area classification in which they are located.

Some specialist fan applications may be driven by pneumatic, hydraulic or mechanical means. Where pneumatic driven fan motors are required they should be fitted with a filter, regulator and lubricator unit regardless of the air supply source. For hydraulic driven fan motors supplying airflow for engine cooling and or combustion purposes, hydraulic fluid should be supplied direct from the applicable engine. In each case the level of protection for specialist fan motors shall be no less than that required of an electric motor used under the same circumstances.

Performance Centrifugal and axial fans are both acceptable providing they fully meet the design requirements below.

Centrifugal fan impellors shall be of the backward curved aerofoil contour blades type. Axial fans shall be of the mixed flow type where the airflow through the impellor is both axial and radial.

All fans shall meet the following requirements for the design operating limits: -

• design duty point selected to maintain optimum efficiency

• non over-loading power characteristics

• non stalling characteristics

• suitable for continuous operation 24 hours per day 365 days per year

Fans shall be selected to allow for an external wind velocity of 27m/s and have a minimum total efficiency of 70% or greater.

Excessive speeds towards the upper limit of the fan's operating range shall be avoided to prevent excessive noise and undesirable loads on bearings, drive assemblies and impellers.

The fan discharge velocity should not exceed 15m/s. Fans having a diameter of 300mm or less may have a discharge velocity up to a maximum of 20m/s.

Fan inlets and outlets should be kept free of obstructions with the nearest adjacent component (cooling coil, fire damper, shut-off damper etc) located not less than 1.5 fan diameters from the fan casing.

Construction Non sparking features shall be an inherent design for all fans. The construction and construction materials shall not permit any steel parts to rub or strike together and cause a spark. The fan shall be protected from sparking in the event of: -





• axial movement of the impeller

• incorrect fitting of guards or shaft during re-assembly

• accidental damage to the drive guard or fan casing

• reasonable wear of the bearing or impeller

Fan casings shall be continuously welded and stiffened to prevent "drumming". The casing shall be constructed to enable the fan impeller to be removed and also incorporate a bolt on inspection hatch.

Fan casings shall be constructed from stainless steel type 316 sheet. Carbon steel casing’s HDP after manufacture may be permitted providing a deviation has been presented to WEL, and subsequently approved by WEL.

Centrifugal fan impellors shall be constructed from stainless steel type 316. Axial impellors may be constructed from stainless steel type 316 or GRP. Carbon steel epoxy coated impellors may be permitted providing a deviation has been presented to WEL and subsequently approved by WEL.

Any other components or materials that form part of the fan assembly shall be corrosion resistant and non-combustible.

Base Frame Composite fan assemblies consisting of a casing/scroll, fan impellor, electric drive motor, drives and safety guards shall be mounted on a common skid base frame complete with anti-vibration mounts.

The skid base frame shall be constructed from carbon steel rolled section to provide a rigid support for the entire fan assembly. The skid shall be fully welded and either HDG or painted after manufacture.

The skid shall be certified as a lifting frame and capable of supporting the whole unit during lifting. The skid shall also include lifting lugs suitable for cranage and rigging gear.

Drive Assemblies Belt driven fans shall be fitted with continuous vee-belts running in multi grooved pulleys. A minimum of two belts shall be required for each drive assembly. Vee belts shall be rated for a minimum of 150% of the transmitted drive power requirement.

Bearings shall be rated for a minimum of 30,000 hours continuous running and be fitted with accessible grease lubricating points extended to a convenient location where necessary.

Maintenance

Design of the fan shall allow easy access for maintenance, including blade and motor change out. Maintenance plans must be included in the site computerised maintenance system (SAP) unless a “run to failure” operation mode has been agreed with the relevant Technical Authority.





Noise and Vibration

Where possible noise levels should be limited to 80dBA at 1 metre away from the fan assembly especially where personnel are in continual exposure.

Resilient mountings shall be selected to provide not less than 95% isolation of all frequencies transmitted to the support frame or structure. Flexible ductwork connections shall be fitted to provide not less than 99% isolation in all frequency bands from the connected ductwork.

Monitoring Fans should be either speed and or pressure monitored for confirmation of normal operation and where applicable shall initiate automatic changeover to a standby fan motor in the event of a duty fan failure (controls shall ensure that fan shut-off dampers also changeover automatically with associated duty/standby fan operation).

Proximity speed sensors are preferred for fan monitoring and shall be arranged to monitor the fan shaft/pulley speed and not the drive motor shaft/pulley. Fault indication and or automatic duty changeover shall be initiated whenever the fan shaft speed falls below 80% of the actual shaft speed.

Pressure differential switches may also be used for fan monitoring and shall monitor the total pressure across the fan. Fault indication and or automatic duty changeover shall be initiated whenever the differential pressure falls below a pre-determined set point value (according to fan selection). Differential pressure switches should not be calibrated to operate at zero differential pressure.

Electrical All electrical equipment and associated controls shall be selected in compliance with the hazardous area classification in which the fans are located.


Earthing bosses shall be fitted to fan skid frames to provide for external earth bonding. A minimum of two stainless steel type 316 earthing bosses shall be welded to skid frames and be tapped for an M10 stainless steel stud complete with nuts and washers.


• W1000SE025 STANDARD : ELECTRICAL ENGINEERING DESIGN W1000SE005_STANDARD: H.V. AND L.V. ELECTRIC MACHINES CAGE INDUCTION TYPE







7.7 APPENDIX 7 FILTERS AND COALESCERS

General The fresh-air composition should be assessed for airborne particulates and moisture content to determine any special filtration requirements.

Filters shall be required to meet the performance criteria in accordance with the following standard: -

AS 1324.1 Air filters for use in general ventilation and air conditioning Part 1: Application, performance and construction

All filter and coalescer materials shall not fragment into the airstream and shall also be non-toxic and non-combustible.

Single Stage Filter Single stage filters may be used for normally unmanned applications such as workshops and stores, generator rooms, fire pump rooms and process areas etc.

Single stage filters shall consist of corrugated filter coalescer panels to remove mist, water droplets and dust particulates. The panels shall be manufactured from dry washable polyester media sandwiched between plastic coated wire mesh and be contained within a stainless steel frame.

The filter coalescer panels performance shall be 99% efficient at 6 microns and shall reduce the salt/air content to less than 0.02 ppm by weight.

When fully loaded the coalescer maximum airflow resistance shall not exceed 250Pa. The maximum face velocity across filter coalescer panels shall be no more than 4.5m/s.

Two Stage Filter Two stage filter arrangements should be used where a higher degree of filtration is required. Typically this includes all normally manned areas, LQ’s, equipment rooms or switchrooms containing sensitive electrical/control equipment, emergency and temporary living quarters and offices.

Two stage filters shall consist of corrugated filter coalescer panels (as described above for single stage filters) in conjunction with pre-filter panels & bag filters to improve efficiency for the removal of dust particulates. In every case the filter coalescer shall be the first stage located upstream of the second stage pre-filter panel & bag filters.

Pre-filter panels shall be of the synthetic media V-form type and may be washable or disposable. The pre-filter panels performance shall have an average arrestance of 90% or more. When fully loaded the pre-filter maximum airflow resistance shall not exceed 250Pa (G4 performance rating in accordance with AS 1324.1).

Bag filters shall be of the deep bed synthetic fibre media type, be self supporting and capable of withstanding air turbulence without the risk of dust break through. Bag filters shall be of the disposable type; appropriate selection should permit a long useful life. The bag filters performance shall have an average arrestance of 95% or more





with a dust spot efficiency of no less than 60%. When fully loaded the bag filter maximum airflow resistance shall not exceed 350Pa (F5 performance rating in accordance with AS 1324.1).

The maximum face velocity across pre-filters and bag filters shall not exceed 2.5m/s.

Where space restrictions dictate, the second stage filter may consist of filter coalescer panels in conjunction with washable or disposable V-form panels only.

Support Housing Filters and coalescers shall be constructed with an outer stainless steel type 316 frame designed to contain the media, provide rigidity and be suitable for insertion into a main support/housing frame.

The main support/housing frames shall be constructed from stainless steel type 316 and shall include airtight seals to prevent air bypass or leakage. All filter types shall be mounted vertically to provide for horizontal airflow.

Main support/housing frames shall incorporate quick release clips or springs to provide straightforward access for filter removal and replacement.

Coalescer support/housing assemblies shall be self-draining and incorporate a drip tray and manometric trap.

Instrumentation Filter cleanliness shall be indicated by installation of a magnehelic circular dial gauge (calibrated in Pa) mounted on the external surface of the filter housing (or AHU) to monitor the pressure drop across the filter.

A pressure differential switch should also be installed to monitor the pressure drop across the filter and provide remote dirty filter indication or alarm.





7.8 APPENDIX 8 FIRE DAMPERS

General Fire dampers shall be provided whenever ducted ventilation air (or non-ducted ie free openings) passes through ‘A’ and ‘H’ rated fire barriers ie bulkheads, deckheads, walls, ceilings or floors. Additionally, fire dampers shall also be installed where required to perform as part of the fire, smoke and gas control philosophy.

The single exception for omitting fire dampers is permitted where ductwork passes through an enclosure it does not serve (ie no outlets or breaks in the duct). Under these circumstances the ductwork shall be constructed to match the highest integrity fire barrier that borders the enclosure through which the ductwork passes.

Dampers shall be of the multiple opposed blade inter-locking type and be capable of correct operation when mounted in any orientation.

Under no circumstances shall any fire damper be permitted for dual purpose ie to additionally function as a non-return, volume control or a pressure control damper.

Performance The maximum leakage rate through damper casing and blades when in the closed position shall not exceed 100L/s per m² of damper face area when subjected to a differential air pressure of 2000 Pa. Under normal operating conditions where the damper is in the fully open position, the airflow resistance shall not exceed 50Pa.

The closure time of pneumatically or electrically actuated dampers shall not exceed 4 seconds for individual or grouped dampers.

Pneumatically actuated dampers shall be suitable for operation under the following compressed air supply conditions: -

• normal operating air pressure 850 kPa(g)

• minimum operating air pressure 400 kPa(g)

• maximum operating air pressure 1000 kPa(g)

All dampers shall equal or exceed the fire rated barrier they serve and be certified and approved by the assigned certification authority such as Lloyd’s or DNV.

Control Unless specified otherwise, all fire dampers shall be of the failsafe type ie fail to closed position upon loss of air, control voltage or power supply. Under special conditions where the damper is normally open (ie fire pump and emergency generator rooms/enclosures) the damper may remain open.

Damper controls shall be integrated to automatically close all fire dampers in accordance with the F&G and ESD shutdown philosophy.

An inherent trigger assembly shall also be provided to independently close the damper whenever activated. The trigger assembly shall incorporate a thermal device mounted





in the airstream of the damper casing and shall be designed to fail at a temperature not exceeding 70°C. The thermal device may be of the frangible bulb, azeotropic or fusible link type.

Construction All damper materials shall be non-combustible and non-corrosive.

Damper casings and blades shall be manufactured from stainless steel type 316 sheet having a minimum thickness of 3mm and be of a fully welded construction. All welds shall be cleaned and passivated to ensure maximum corrosion protection. Damper blades shall be of aerofoil design to minimise airflow resistance.

Blade shafts and linkages shall also be manufactured from stainless steel type 316. Bushes/bearings associated with stainless steel blade shafts shall be manufactured from graphite bronze to prevent galling or seizure with stainless steel parts.

Components All associated components for each damper shall be housed in a common protective control box enclosure. Each damper shall incorporate the following componentry as a minimum: -

Pneumatic actuated fire dampers Electric actuated fire dampers Pneumatic actuator Electric actuator (220-240VAC 50/60Hz) Thermal trigger assembly Thermal trigger assembly Solenoid valve (3-port, 2-way) Two microswitches Quick exhaust valve Two microswitches

Two independent volt-free microswitches shall be provided for open and closed remote indication and monitoring. One microswitch shall be mounted to activate when the damper blades travel to within 5% of their fully open position. The second microswitch shall be mounted to activate when the damper blades travel to within 5% of their fully closed position.

An extension rod (fixed to a blade shaft) that protrudes through the control box cover shall provide local open and closed indication. Open and closed labels shall be securely fixed to the cover and be clearly visible from a distance.

Electrical All electrical components shall be suitable for a Class 1 Zone 1 hazardous area classification regardless of the area classification in which the damper is located.

Electric actuators, solenoid valves, microswitches and terminal boxes shall be certified EEx'e' as a minimum. Control box enclosures shall be weatherproof to IP56.

All electrical componentry shall be factory pre-wired into a terminal box or boxes mounted on the external surface of the control box enclosure.

Each terminal box shall be provided with sufficient 20mm cable gland entries for connection of incoming cables. Where Intrinsically safe components are used, separate terminal boxes shall be provided for IS and non-IS circuits.





All electrical equipment shall be fully earth bonded. A main earthing post or terminal strip shall be provided in each terminal box for the earthing core of each incoming and outgoing cable.

A stainless steel type 316 earthing boss shall be provided for external earth bonding. The earthing boss shall be welded to the damper casing and be tapped for an M10 stainless steel stud complete with nuts and washers.


• W1000SE025 STANDARD : ELECTRICAL ENGINEERING DESIGN W1000SJ010_STANDARD - INSTRUMENT INSTALLATION







7.9 APPENDIX 9 GENERAL DAMPERS

General The following general types of dampers are commonly used in HVAC systems: -

• fan shut-off dampers – to prevent air bypass/recirculation for duty/standby

fan arrangements

• non-return dampers – to prevent backflow of air

• volume control dampers – for system air balancing

• pressure relief dampers – for pressurisation control

All dampers shall be required to function correctly when subjected to system pressures up to 2500 Pa.

Performance The maximum leakage rate through shut-off and non-return damper blades when in the closed position shall not exceed 150L/s per m² of damper face area when subjected to a differential air pressure of 2000 Pa.

Airflow resistance through shut-off and volume control dampers when in the open position shall not exceed 50Pa.

Airflow resistance through non-return and pressure relief dampers should be suitable for their function.

Fan Shut-off Dampers Fan shut-off dampers shall be of the multiple opposed blade type having aerofoil section blades. Shut-off dampers serving fans having circular casings shall be rectangular complete with transition pieces for connection to the fan and or ductwork circular flange connection.

Shut-off dampers shall be operated automatically by either pneumatic or electric actuators.

Pneumatically actuated dampers shall be suitable for operation under the following compressed air supply conditions: -

• normal operating air pressure 850 kPa(g)

• minimum operating air pressure 400 kPa(g)

• maximum operating air pressure 1000 kPa(g)

Pneumatically operated dampers shall be provided with single action, spring return type actuators configured to close the damper upon loss of the pneumatic air supply.

Each pneumatic damper shall incorporate and be controlled by a 3-port, 2-way solenoid valve. Normally energised the solenoid valve shall supply pneumatic air onto





the actuator to open the damper. Whenever the solenoid valve is de-energised, the damper shall close by venting pneumatic air to atmosphere.


• W1000SJ010_STANDARD - INSTRUMENT INSTALLATION

Alternatively dampers may be electrically actuated where a pneumatic air supply is unavailable.

Volume Control Dampers Volume control dampers shall be of the multiple opposed blade type capable of being manually adjusted and locked in any position. The damper shall be capable of regulating airflow rates with a velocity of up to 25m/s.

Non-return Dampers Non-return dampers shall be of the gravity operated parallel blade action type and must therefore be mounted vertically in all cases. The damper may be either single or multiple blade dependent on the face area of the damper. The damper shall be fitted with positive sealing side blade seals and blade edge seals.

Pressure Relief Dampers Pressure relief dampers shall be of the gravity operated parallel blade action type and must therefore be mounted vertically in all cases. The damper may be either single or multiple blade, depending on the face area of the damper. An adjustable tension spring or counterbalancing weight shall be provided to restrict blade opening and maintain the required rate of relief air.

Pneumatically controlled pressure relief dampers shall not be permitted.

Construction All damper materials shall be non-combustible and non-corrosive.

Damper casings and blades shall be manufactured from stainless steel type 316 sheet having a minimum thickness of 3mm. Damper casings shall be of a fully welded construction. All welds shall be cleaned and passivated to ensure maximum corrosion protection.

Blade shafts and linkages shall also be manufactured from stainless steel type 316. Bushes/bearings associated with stainless steel blade shafts shall be manufactured from graphite bronze to prevent galling or seizure with stainless steel parts.

Electrical (Fan Shut-off Dampers Only) Electrically actuated dampers shall incorporate motorised actuators rated for 220-240VAC 50/60Hz power supply.

All electrical equipment, electric actuators and solenoid valves shall be suitable for the hazardous area classification in which the damper is located.

All electrical componentry shall be factory pre-wired into a terminal box or boxes mounted on the external surface of the control box enclosure.







A stainless steel type 316 earthing boss shall be provided for external earth bonding. The earthing boss shall be welded to the damper casing and be tapped for an M10 stainless steel stud complete with nuts and washers.








7.10 APPENDIX 10 GRILLES AND DIFFUSERS

General Grilles and diffusers fall into two distinct categories. Those that serve non-hazardous areas and those used to serve hazardous areas.

Grilles and diffusers located in LQ’s and other non-hazardous areas shall be of a light duty type construction. The construction materials may be of aluminium complete with an anodised or baked enamel finish to suit the chosen architectural finish. In all cases these grilles and diffusers shall not permit any line of sight into ceiling voids or ductwork.

Grilles and diffusers mounted in hazardous areas shall be of a heavy-duty type construction. The construction materials shall be of stainless steel type 316 and be fabricated to withstand mechanical impact.

Ceiling Slot Diffuser (Light Duty) Ceiling slot diffusers should be used for cinema rooms or similar where draft-less air distribution is required. They are suitable for supply or return air applications and should be selected with a frame fastening that matches and easily fits into the suspended ceiling system.

Supply-air ceiling slot diffusers shall incorporate air pattern controls to give 180° airflow adjustment through each slot (single or multiple slot unit). The ceiling slot diffuser shall also include a thermal/acoustic insulated plenum box complete with a volume control damper and ductwork spigot connection. Alternatively the volume control damper may be duct mounted upstream of the slot diffuser it serves.

Return air ceiling slot diffusers shall not require air pattern controls. Plenum boxes shall be fitted with a volume control damper (alternatively duct mounted upstream) and spigot connection but shall not require thermal insulation.

Ceiling slot diffusers intended for use with fluorescent light fittings may also be used providing they incorporate the same features as for the general type described above. However, careful attention should be given to the compatibility between the selected light fittings and slot diffuser.

Eyelash Diffuser (Light Duty) Eyelash diffusers may be used generally for all supply-air requirements and are especially suited for high or low sidewall applications, suspended ceiling systems as well as direct surface mounting on rigid ductwork. Incorporating individually adjustable eyelash type curved blades these diffusers offer a wide variety of air-throws and deflection patterns.

Eyelash diffusers may be of the multi-pattern core type with one, two, three or four-way air-throw deflection patterns as required.

The diffuser shall be fitted with an opposed blade damper to enable fine-tuning of the airflow rate. Adjustment of opposed blade dampers shall be through the diffuser face.





For eyelash diffusers that are direct surface mounted on rigid ductwork, a stream splitter shall also be fitted to the back of the diffuser ensuring an even airflow route through each diffuser.

Round Ceiling Diffuser (Light Duty) Round ceiling diffusers may be used generally for all supply-air requirements but may not be as easily integrated into certain types of suspended ceiling system. They are particularly effective for rapid maximum diffusion.

Round ceiling diffusers may be of the fixed or adjustable louvre core type with removable louvre cores. The adjustable louvre cores shall permit the centre core to be wound up or down to modify the air-throw pattern.

All round ceiling diffusers shall be fitted with a radial blade or butterfly volume control damper adjustable through a hole in the centre cone of the diffuser.

Square/Rectangular Ceiling Diffuser (Light Duty) Fixed blade square/rectangular ceiling diffusers may be used generally for all supply-air requirements and can also be easily integrated into all types of suspended ceiling system. They are particularly effective for rapid mixing of supply-air with room air when used for low ceiling applications - typical for use in LQ enclosures and modules.

Fixed blade square/rectangular ceiling diffusers may be of the multi-pattern core type with one, two, three or four-way air-throw patterns as required. The core shall be completely removable by use of spring-loaded pins or retaining clips.

The diffuser shall be fitted with an opposed blade damper to enable fine-tuning of the airflow rate. Adjustment of opposed blade dampers shall be through the face of the diffuser without the need to remove or alter the core pattern.

The diffuser shall also be fitted with a thermal/acoustic insulated plenum box complete with a ductwork spigot connection.

Sidewall Single/Double Deflection Grilles (Light Duty) Sidewall defection grilles may be used generally for all supply-air requirements and may be mounted in the walls of enclosures or directly surface mounted on exposed rigid ductwork.

Incorporating individually adjustable single or double deflection aerofoil blades these grilles offer a wide variety of horizontal and vertical air-throw patterns. Sidewall grilles shall also incorporate a removable core.

The grille shall be fitted with an opposed blade damper to enable fine-tuning of the airflow rate. Adjustment of opposed blade dampers shall be through the grille face.

For sidewall grilles that are direct surface mounted on rigid ductwork, a stream splitter shall also be fitted to the back of the grille ensuring an even airflow route through each grille.

Exhaust & Return Grilles(Light Duty) Square/rectangular ceiling grilles may be used generally for all exhaust and return air requirements and can also be easily integrated into all types of suspended ceiling





system. Alternatively they may be direct surface mounted on to exposed rigid ductwork.

Square/rectangular ceiling grilles shall be of the fixed square egg-crate pattern core. The core shall be completely removable by use of spring-loaded pins or retaining clips.

Each grille shall be fitted with an opposed blade damper to enable fine-tuning of the airflow rate. Adjustment of opposed blade dampers shall be through the face of the grille without the need to remove core.

The grille shall also be fitted with a plenum box complete with a ductwork spigot connection.

In toilet and shower areas where small exhaust-air volumes are required, adjustable truncated exhaust valves may be used in lieu of exhaust grilles. Exhaust valves may be constructed from PVC.

Transfer Grilles (Light Duty) Transfer grilles may be of the ceiling mounted type whereby an associated transfer duct and ceiling mounted grilles straddle the enclosures requiring air transfer. Additionally transfer grilles may be of the door-mounted type.

Where transfer grilles are installed into ceiling systems they shall be selected to match the adjacent ceiling mounted grilles or diffusers. The associated transfer ductwork shall be constructed to the same standard as the local ductwork. The transfer ductwork should also include acoustic insulation to prevent noise being transmitted from one enclosure to another.

Door transfer grilles shall be completely sight-proof and suitable for a door thickness of 25mm or more. The grille shall consist of a main flanged frame with an inverted chevron blade core. An auxiliary backing frame shall fit into the main frame to provide a finished appearance on both sides of the door.

All transfer grilles or ductwork shall not penetrate through fire rated bulkheads or doors unless an associated fire damper is installed.

Exhaust Air Grille (Heavy Duty) Exhaust-air requirements should be provided by grilles with a simple steel mesh core and an opposed blade damper fitted at the back of the grille. The damper shall be adjusted through the face of the mesh.

Where the purpose of the grille is only to prevent airborne rubbish entering the duct then a simple flange framed grille with coarse mesh is adequate.

Wherever ductwork is intentionally exposed within an enclosed space, the grilles may be mounted directly to the rigid duct wall.

Supply Air Grille (Heavy Duty) Supply-air distribution should be provided by single or double deflection type grilles complete with opposed blade dampers for the majority of heavy-duty applications. Adjustment of opposed blade dampers should be through the face of the grille without the need to remove or alter the selected air distribution pattern.





For areas where the purpose of the grille is only to "dump" air, a basic framed metal mesh grille may be adequate.

Wherever ductwork is intentionally exposed within an enclosed space, the grilles may be mounted directly to the rigid duct wall providing a stream splitter is fitted to the back of the grille to ensure an even airflow route through each grille.

7.11 APPENDIX 11 HEATER BANKS

General This section describes the requirements associated with primary or main heater banks only. For trim heating as provided by constant volume reheat terminal units refer to Appendix 3.

Heating, where required for non-hazardous enclosures, should be provided by electric heater banks located in the AHU or supply-air ductwork.

Heating, where required for hazardous area enclosures, should be provided by water/glycol heating coils located in the AHU or supply-air ductwork and be served directly or indirectly form a low pressure low temperature closed loop heating system.

In either case it may be necessary for a number of primary or main heater banks to be provided for separate zones or where enclosures require varying conditions.

ELECTRIC HEATER BANKS

Performance Heater banks shall fully comply with AS/NZS 3102 and be supplied with a certificate of conformance as a minimum.

Each electric heater bank shall be configured for a maximum capacity of 50kW per unit and be suitable for continuous and intermittent operation. Heater banks shall be limited to a 3kW capacity for single-phase power supplies. For capacities above 3kW, three-phase power supplies shall be used with elements arranged to ensure the out of balance load across each phase is not greater than 2%.

The heater bank should provide minimal airflow resistance and air turbulence. The minimum air velocity shall be 2.5 m/s with a maximum of 5 m/s in all cases.

Elements shall have a maximum surface temperature rating of 200°C (T3) when operating in still air conditions. Under normal operating airflow conditions elements shall not exceed a surface temperature of 135°C (T4).

All elements shall be provided with element supports to prevent vibration and sagging. Where elements do not match the cross sectional area of the AHU or ductwork internal dimensions, the space beyond the elements shall be fitted with 316 type perforated steel sheet of 50% open area.

All electric heater banks shall be encapsulated by thermal insulation fixed directly to the AHU or ductwork internal casing. The insulation shall also be installed for a distance of not less than 250mm upstream and 250mm downstream from the heating





elements. Thermal insulation shall be non-combustible and have a coefficient of heat transfer not greater than 30 W/m²K at 100°C.

Control/Safety Devices Heater banks with capacities above 10kW shall be split into equal capacity stages with each stage arranged to provide an even heat distribution over the total cross sectional area of the air stream.

Thyristor or step control shall be provided to energise each heating stage to ensure smooth temperature control and reduce the electrical circuit switching load.

The heater bank shall also be fitted with devices to satisfy both of the following requirements and safeguard against overheating under abnormal operating conditions:-

• a thermal cut-out device or a supply-air failure switch to interrupt the power supply to the heater elements upon loss of the supply airflow

• a manual reset thermal cut out device to monitor the air temperature in the immediate vicinity of the heater elements - set to trip at 120°C and interrupt the power supply to the heater elements

Thermocouples or resistance temperature devices should also be used to protect each heating stage.

Construction/Mounting Heating elements shall be constructed from nickel-chrome resistance wire contained within magnesium oxide, all encased within an Incoloy 800 sheath. Elements may be provided with fins to increase the heat exchange surface but only where full compliance with the surface temperature requirements is strictly met.

Where installed within an AHU the heater bank shall be mounted on a purpose built stainless steel type 316 support frame. When installed in supply-air ductwork the heater bank casing shall be constructed from the same material as the adjoining ductwork and be directly flange mounted in accordance with the ductwork flange drilling detail.

In either case heating elements shall be mounted on a support plate to enable individual element withdrawal without the need to remove the support frame or ductwork heating section. Where the heating element passes through the mounting plate they shall be clamped by an airtight mounting bushing and fire retardant gasket.

Electrical All electrical equipment and associated controls shall be selected in compliance with the hazardous area classification in which the heater bank is located.

Separate terminal boxes should be provided for power supplies to elements and control circuits for safety devices. Multiple terminal boxes may be required for step or thyristor controlled heater stages.





The location of termination boxes shall be determined by layout and access considerations for servicing, maintenance and withdrawal of the heating elements. The degree of protection required for all terminal boxes shall be a minimum of IP56.

All heating element and incoming cable terminations shall be made using crimped compression lugs for threaded terminal posts and/or crimped compression pins for screw terminal rails.

All electrical equipment shall be fully earth bonded. A main earthing post or terminal strip shall be provided in each terminal box for the earthing core of all incoming and outgoing cables.

A stainless steel type 316 earthing boss shall be provided for each individual heater bank for external earth bonding. The earthing boss shall be welded to the support frame/ductwork casing and be tapped for an M10 stainless steel stud complete with nuts and washers.




WATER/GLYCOL HEATING COILS

Heating coils shall have a face velocity of not more than 3.5 m/s and fin spacing not exceeding 2.5mm. Heating coils shall be factory pressure tested at 2000 kPag(g) in accordance with the manufacturers test procedures.

Heating coils shall be constructed from copper tubes with copper fins and shall be coated with a suitable finish such as electro-tinning to provide adequate protection in a marine environment. Alternatively the manufacturers own protective finish may be considered if specifically developed or suited for marine environments.

The perimeter holding-frame and tube end sheets shall be constructed from brass. The holding-frame shall be constructed for flange mounting allowing the heating coil to be easily removable. Intermediate support plates should be provided where necessary to add rigidity to the coil. Headers and return bends shall be located out of the airstream. Each heating coil shall be provided with a drain point and air vent.








7.12 APPENDIX 12 HUMIDIFIERS

General Steam humidifiers shall only be provided where they can be located within a non-hazardous enclosure such as within the HVAC plantroom.

All humidifiers shall be of the electrode-boiler, atmospheric steam generating type and should be wall mounted on or adjacent to the main AHU being served.

The unit shall be a self-contained package, housing all steam generating equipment, control/starting gear and safety devices within a purpose built cabinet.

Performance The steam humidifier shall generate sufficient steam to satisfy the specific project requirements as determined by the HVAC calculations.

Humidifiers shall generate sterile odourless steam from the facilities potable water supply and shall be suitable for water pressures ranging from 100 to 800 kPa(g).

Water Supply The humidifier shall be fitted with a water inlet strainer, pressure regulator and a fill cup that provides a minimum 25mm air gap for the incoming water supply to prevent back feeding or contamination of the inlet water supply. The fill cup shall be fitted with a safety overflow drain.

Pipe connection fittings shall be provided for the potable water inlet, steam outlet and drain.

Steam Cylinder Steam cylinders shall be constructed from polypropylene and be easily removable to facilitate service and maintenance. Each steam cylinder shall be a two part split type arrangement enabling quick access to replace electrodes, clean electrode mesh guards and remove any scale deposits.

Each steam cylinder shall be fitted with a water level sensing electrode to close the inlet water valve and prevent overfilling.

Steam Injection Where possible the steam piping and injection distributor should be installed at a higher level than the humidifier unit. Should the piping be installed below the level of the unit, then a condensate separator and drain must be installed to the nearest drain point.

The steam piping between the humidifier and the injection distributor shall be manufactured from high temperature cotton-braided rubber steam hose.

The injection distributor shall be manufactured from stainless steel type 316 and be perforated for direct injection of steam into the airstream. The injection distributor shall be naturally inclined to ensure continual condensate drainage and thereby avoid the requirement of a condensate return line.





The steam injection distributor shall be duct mounted and should be positioned to inject steam into the AHU at the supply-air fan inlet.

Controls An electrical interlock shall be provided to prevent the humidifier from operation whenever the main supply-air fan is shut down. Volt-free contacts shall also be required for remote operating and fault status.

The humidifier shall automatically shut down in the event of high over-current, a water supply fault or a drain pump blockage.

The humidifier front control panel shall be factory fitted and pre-wired with the following controls and indicators: -

• alpha-numeric display and keypad

• power on/off switch

• manual drain selector switch

• power on indicator lamp

• warning indicator lamp

The alphanumeric display and touch sensitive keypad shall enable initial set-up, configuration, diagnostics and operating parameter adjustments.

A remote mounted humidistat shall provide a 0-10VDC signal to the humidifiers on-board microprocessor controller to modulate steam production and satisfy the humidity set point. The humidistat should be remotely mounted for sensing of general exhaust-air.

In response to the humidistat control signal, electrode operation shall be energised by semi-conductors, thyristor or step control gear for optimum steam output. Filling and draining of the steam cylinder shall be automatically monitored and controlled by the on-board microprocessor.

The humidifier shall undergo an automatic time-controlled pump assisted drain cycle. Drain cycle intervals shall be determined automatically by sensing the degree of water conductivity and regulating the fill and drain frequency accordingly.

Electrical All electrical componentry shall be factory fitted and fully pre-wired. All pre-wired cabling shall be terminated made using crimped compression lugs for threaded terminal posts and/or crimped compression pins for screw type terminals. The minimum size cable for all power wiring shall be 2.5mm².

A dedicated electrical compartment shall house all power/starting, control and safety devices and include a termination rail for connection of incoming main power and external control cabling.

All electrical equipment shall be fully earth bonded. A main earthing post or terminal strip shall be provided for the earthing core of all incoming and outgoing cables.





• Also refer to the requirements of the following Woodside Standards: -



7.13 APPENDIX 13 PUMPS General The following requirements are applicable to pumps used for CHW, TW, condenser water and heating water applications associated exclusively with HVAC systems.

Pumps shall be of the centrifugal type, directly driven by an electric drive motor. Each pump shall be suitable for continuous operation as the primary circulating water pump serving the applicable closed loop pipework circuit.

All closed loop pipework circuits shall typically incorporate two equal capacity pumps to provide a 100% duty and 100% standby arrangement. Piping circuits without any standby redundancy shall not be permitted unless a deviation has been approved.

Pump sets shall be mounted on a common base skid complete with all associated componentry such as flexible pipework connections, isolating valves, check valves, strainers, discharge and suction gauges.


• W1000MM103 STANDARD: PUMPS, SELECTIONS AND SPECIFICATION

Performance All centrifugal pumps shall be close coupled and may be either: -

• single stage or multiple stage in-line type

• single stage end suction type

Pump impellors shall be of the backward curved aerofoil contour type. All pumps shall meet the following requirements for the design operating limits: -

• design duty point shall be selected to maintain optimum efficiency

• non over-loading power characteristics

• non stalling characteristics

• be suitable for continuous operation 24 hours per day 365 days per year

Pumps shall be selected to avoid cavitation problems. The available suction head of the pipework system at the most adverse operating condition shall be equal or greater than the required pump suction head to ensure cavitation is avoided.








Pump operating speeds of 3600 RPM or higher should be avoided. Operating speeds of 1800 RPM or lower are favoured to reduce the possibility of adverse noise or vibration.

The pump discharge velocity should not exceed 6m/s. The suction velocity should not be less than 1.2m/s. Pumps should be selected for a minimum total efficiency of 70% or greater.

Construction Pump casings shall be fabricated from cast iron and may be of the horizontal split case type or back pull-out type enabling access to working parts without disturbing the connecting pipework.

Centrifugal pump impellors shall be constructed from zinc free bronze or stainless steel. The drive shaft, shaft sleeve and wear ring shall all be constructed from stainless steel as a minimum.

Any other components or materials that form part of the pump assembly shall be corrosion resistant and non-combustible.

Base Frame A single skid base frame shall be constructed from carbon steel rolled section to provide a rigid support for the entire pump assembly. The skid shall be fully welded and either HDG or painted after manufacture.

The skid shall be certified as a lifting frame and be capable of supporting the whole unit during lifting. The skid shall also include lifting lugs suitable for cranage and rigging gear.

Electrical All electrical equipment and associated controls shall be selected in compliance with the hazardous area classification in which the pumps are located.


Earthing bosses shall be fitted to pump skid base frames to provide for external earth bonding. A minimum of two stainless steel type 316 earthing bosses shall be welded to skid base frames and be tapped for an M10 stainless steel stud complete with nuts and washers.








7.14 APPENDIX 14 SOUND ATTENUATORS

General The performance of a sound attenuator is maximised when located in ductwork passing from high to low noise level areas. Typically sound attenuators are installed in main ductwork runs prior to leaving the HVAC plantroom. Sound attenuators may also be installed in local ductwork braches that serve rooms requiring low noise levels.

Attenuators should not be located at the inlet or discharge ductwork of fans or close to any bends.

Where sound attenuators are required for galley or laundry exhaust systems they shall be designed and constructed to eliminate the risk from grease or lint accumulation and the subsequent fire hazard these products possess.

Shale shaker exhaust, mud tank exhaust and any air system where excessive air-borne dirt is present shall not be fitted with a sound attenuator.

Performance The dynamic insertion loss must be equal or greater in all frequency bands than the required value in accordance with the HVAC design noise calculations. The noise level generated by the unit itself should also be considered in determination of a suitable attenuator.

Leading edges of centre and side splitters shall be aerodynamically designed to minimise the airflow resistance and air turbulence.

Construction The casing and internal splitters shall be of the same material as the adjoining ductwork ie stainless steel sheet type 316 or galvanised steel sheet as required.

Fully welded flange connections shall be provided for connection to adjoining ductwork, drilled in accordance with the ductwork flange drilling detail.

Internal splitters shall be fabricated from perforated sheet and be securely fixed to the casing. The splitters shall be filled with non-hygroscopic and fire retardant acoustic infill media. A polyester lining shall be fitted between the acoustic infill media and the perforated sheet to prevent any infill media fibres migrating into the airstream.



TAG No:1 Service description:

2 Location:3 Duty/Fire Zone:

4 Manufacturer:5 Model No:6 Type:7 Maximum Air Flow: NM3/Hr8 Operating Temp Range: °C9 Minimum Air Pressure: kPa(ga)

10 Maximum Air Pressure: kPa(ga)11 Actuator Material (note 2):12 Actuator Air connect'n size: NPTF13 Weight Includ. Access: kg14 Mounting Flange/W15 Insulation Material:16 Fire Rating Class:17 IP Rating:18192021222324

25

26 Check Valve Manufacturer:27 Check Valve Model No:28 Check Valve Material (note 2):29 Filter Regulator Manufacturer:30 Filter Regulator Model No:31 Filter Regulator Material (note 2):32 Frangible Bulb Manufacturer:33 Frangible Bulb Model No:34 Frangible Bulb Oper. Temp: °C35 Frangible Bulb Material (note 2):36 Position Switch Manufacturer:37 Position Switch Model No:38 Position Switch Tag No:39 Tubing and Fittings:40 Hook-up Number:4142

12

REV. DATE PREPD CHKD APPD WEL

Project Ref: Rev:Document No:

WEL Std W9000RJ001

Woodside Energy Ltd.REVISION DESCRIPTION

ACN 005 482 986

Where aluminium is offered it must be coated in accordance with WEL standard W9000SM001.

Under no circumstances shall 304 or other non-molybdenum containing stainless steels be used,this shall also include bare aluminium and its alloys. The vendor may offer his standard equipment for WEL approval.

DESIGN DATA:

ACCESSORIES

Notes:316 st.stl. tags stamped with Tag No in 10mm characters shall be permanently attached using 316 st.stl. screws or rivets.

WEL Std W9000RJ001 WEL Std W9000RJ001

Datasheet for HVAC FIRE DAMPER - PNEUMATIC ACTUATORSERVICE:

Solenoid Details Based on WEL Form A3000SJ048.052:

IP56

Pepperl & FuchsNJ4-12GK-SN fail safe

Pepperl & Fuchs Pepperl & FuchsNJ4-12GK-SN fail safe NJ4-12GK-SN fail safe

elded:

IP56 IP56





SERVICE: TAG No:1 Service description:



10 Maximum Air Pressure: kPa(ga)11 Actuator Material (note 2):12 Actuator Air connect'n size: NPTF13 Weight Incl. Access: kg14 Mounting Flange/Welded:15 Insulation Ma16 Fire Rating Cla17 IP Rating:18192021222324

25

26

27 Filter Regulator Manufacturer:28 Filter Regulator Model No:29 Filter Regulator Material (note 2):30 Position Switch Manufacturer:31 Position Switch Model No:32 Position Switch Tag No:33 Tubing and Fittings:34 Hook-up Number:35363738394041

12



Woodside Energy Ltd.ACN 005 482 986

Under no circumstances shall 304 or other non-molybdenum containing stainless steels be used,this shall also include bare aluminium and its alloys. The vendor may offer his standard equipment for WEL approval.Where aluminium is offered it must be coated in accordance with WEL standard W9000SM001.

REVISION DESCRIPTION

DESIGN DATA:

ACCESSORIES

Notes:316 st.stl. tags stamped with Tag No in 10mm characters shall be permanently attached using 316 st.stl. screws or rivets.

WEL Std W9000RJ001 WEL Std W9000RJ001 WEL Std W9000RJ001

Datasheet for HVAC AIR DAMPER - PRESS. CONT. ACTUATOR

NJ4-12GK-SN fail safe NJ4-12GK-SN fail safe NJ4-12GK-SN fail safePepperl & Fuchs Pepperl & Fuchs Pepperl & Fuchs

IP56

I/P Conv. BaseWEL Form A3000SJ048.051:Diff. Pressure Transmitter Based on WEL Form A3000SJ048.011:



terial:ss:

IP56IP56

d on Relative Section of



TAG No:1 Service description:



10 Maximum Air Pressure: kPa(ga)11 Actuator Material (note 2):12 Actuator Air connect'n size: NPTF13 Weight Incl. Access: kg14 Mounting Flange/Welded:15 IP Rating:161718192021222324

25

26 Check Valve Manufacturer:27 Check Valve Model No:28 Check Valve Material (note 2):29 Filter Regulator Manufacturer:30 Filter Regulator Model No:31 Filter Regulator Material (note 2):32 Position Switch Manufacturer:33 Position Switch Model No:34 Position Switch Tag No:35 Tubing and Fittings:36 Hook-up Number:373839404142

12



NJ4-12GK-SN fail safe NJ4-12GK-SN fail safe NJ4-12GK-SN fail safePepperl & Fuchs Pepperl & Fuchs Pepperl & Fuchs

IP56 IP56 IP56

Solenoid Details BaA3000SJ048.052:

Datasheet for HVAC AIR DAMPER - SHUT OFF ACTUATORSERVICE:

DESIGN DATA:

ACCESSORIES

WEL Std W9000RJ001 WEL Std W9000RJ001 WEL Std W9000RJ001

Notes:316 st.stl. tags stamped with Tag No in 10mm characters shall be permanently attached using 316 st.stl. screws or rivets.Under no circumstances shall 304 or other non-molybdenum containing stainless steels be used,this shall also include bare aluminium and its alloys. The vendor may offer his standard equipment for WEL approval.Where aluminium is offered it must be coated in accordance with WEL standard W9000SM001.

REVISION DESCRIPTION

Woodside Energy Ltd.ACN 005 482 986

sed on WEL Form



hvac specs woodside

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