INDEX

1.0 GENERAL

2.0 ORAGANISATION

3.0 POLICY

4.0 QUALITY ASSURANCE / QUALITY CONTROL

5.0 TANK ERECTION PROCEDURE – CONVENTIONAL

6.0 TANK ERECTION PROCEDURE – HYDRAULIC JACKING

7.0 HYDRAULIC JACKING PROCEDURE

8.0 PROCEDURES REPORTS TO BE MAINTAINED AT SITE

APPLICABLE CODES AND STANDARDS

SR. NO. DESCRIPTION REF. CODE

1. CONSTRUCTION OF CPP, UTILITY,

RTF SMALL TANKS

API 650 & REAL / NES SPECIFICATIONS

2. WELDING DETAILS ASME SEC – IX (LATEST REVISION)

3. MATERIALS ASME SEC.-II PART A ( FERROUS METALS)

ASME-SEC-II PART B (NON FERROUS METAL)

4. FILLER METALS ASME SEC-II PART-C

5. NON-DESTRUCTIVE TESTING ASME SEC-V

6. RADIOGRAPHY ACCEPTANCE

CRITERIA

ASME-SEC-VIII

UW 51(B)

7. CALIBRATION IS : 2007 & 2008

8. PIPING ASNI / ASME-B 31.3.

9. PAINTING

A) SURFACE PREPARATIONSIS 055900 & SPEC. NO. 25194-3PS-GAW

005-REV.02

SA 2 FOR UNDER SIDE OF BOTTM PLATE,

SA 2 ½ FOR SHELL, ROOF , DECK ,ETC.

(SWEEDISH STANDARD)

B) PAINTS APPLICATION AS PER PURCHASER REQUIREMENT

1.0 GENERAL

The Contract shall be per formed under the control of a documented quality system. The Project Quality Plan outlines the means where by AEL’S quality system will be implemented an provides a basis upon which quality assurance audits may be undertaken.

This Project Quality Plan describes manufacturing policies, quality assurance functions and control activities related to construction of CPP, UTILITY, RTF small Tanks.

Any amendment to this document requires the authorization of AEL’S General Manager and consultant’s Quality Assurance Representative who will review the QAP at regular intervals.

2.0 ORGANISATION

The organization chart for this project is at reflected in Fig. 1.

2.1 FUNCTION DESCRIPTIONRESIDENT CONSTRUCTION MANAGER (R.C.M.)

The Resident Construction Manager shall report to the General Manager (Construction).

The following tasks and responsibilities shall apply :

• Control all influences external to the project team, ensure efficient and unhindered performance to the contract scope, budget, schedule and the performance of sub-contractors.

• Monitor and control interface between the client and the project team.

• Review implementation of project planning system, submit bar charts and work schedule to client.

• Monitor all project work with respect to contract scope of work and HSE. Notify to General Manager any change of scope. Ensure that all change of work is fully authorized by client / consultant in writing.

• Implement the document control procedure. Ensure the correct compilation of all document packages for delivery.

• Furnish all project reports.

• Fiancée

The General Manager (GM) shall be ultimately responsible to the client for performance of the contract. The RCM shall be responsible for monitoring all aspects related to performance of contract and shall immediately advise the General Manager areas of conflict.

PLANNING AND SAFETY ENGINEER

His functions include :

• Preparation of daily, weekly and monthly planning programmes, monitor them and report progress to RCM and client.

• Assess and record daily work progress for reporting to RCM.

• The Planning Engineer shall liaise with the client’s Planning Engineer. All communications or exchanges shall be recorded and passed via the RCM. All instructions must be confirmed at RCM level Assess and record daily work progress for reporting to RCM.

• Control the receipt and movement of all documents and drawings relating to the project work.

• Preparation of HSE plan for endorsement by the RCM and submission to the client for approval.

• For implementation of Safety a full time qualified and experienced safety Officer & Safety Supervisors shall be a full time person.

CONSTRUCTION MANAGER (C.M.)

His responsibility is to :

• Control and monitor work of assembly, welding, inspection & testing of Tanks. He is responsible for safety of all personnel within the erection area.

• Report to the RCM on al matters affecting the safety and performance of work, including the requirement of equipment, consumables and manpower resources to meet the schedule.

• Deal with all problems and difficulties encountered by the crew members and ensure a harmonious work atmosphere at the project site.

INSPECTION ENGINEERS (QA/QC)

The Inspection Engineers group shall be jointly and severally responsible for implementation of Project Quality Plan from material and drawings & welding consumables receipt at site to final handing over.

This group shall maintain records of all standards for fabrication and erection as per approved construction drawings, specification

They are responsible for inspection planning which shall include :

• Sequencing of inspection requirements for fabrications and erection with identification of mandatory “HOLD” points.

• Scheduling inspection & tests. Liaisoning with consultant’s Surveyor to approve inspection and test.

• Preparation of inspection procedures which establish the operation/activity to be inspected, the inspection methods, the acceptance and rejection criteria, the controlling procedure for documents, the formats for recording inspection results.

• Control the acceptance of all material that from part of the finished equipment including welding consumables storage & handling upon receipt at the project stores before issuance of work.

• Maintenance of al records pertaining to inspection work carried out and certified by consultant’s inspector.

3.0 POLICY

Design of the storage tanks are based on API 650 and other relevant codes for construction of storage tanks. Revision to QAP may be based on :

• Over riding customer requirements in so far as they do not contravene design codes.

• Change in manufacturing procedures with prior agreement of customer and NES, (Authorised Inspector) with a deviation request.

Repairs – strictly in accordance with a repairs procedure duly approved by customer, NES and Engineer QA/QC. Necessary precautions and extent of nondestructive testing as stipulated by design code customer specification shall be indicated in the repairs procedure.

4.0 QUALITY ASSURANCE / QUALITY CONTROL.

Approved fabrication drawing shall be issued by the design department. Controlled number of paints and approved revision shall be issued for site fabrication and erection / welding work. Engineering department shall issue E.C.N. (Engineering Change Note) every time the drawing sheet is revised, indicating the approval

Status and instruction when superseded drawings is to be destroyed. Fabrication AFC drawings shall be made available to projects, materials, QA/QC, manufacturing, welding, engineering, departments as well as to consultant.

MATERIALS

Specification and grades of all materials shall to Bill of materials and fabrication drawing requirements. If there is any deviation in the material selection from the initial material list supplied by the Client, they shall be duly sorted out and shall be got approved from consultant raising a deviation report. Prior to procurement, client’s specific requirements shall be conformed to.

Conformance shall be checked at pre-order, receipt, inspection and in-process stages.

All materials shall be bear manufacturer’s markings and shall co-relate with Mill Test Certificates. Markings shall be transferred to cut pieces with consultant’s stamping to keep track of their identity.

WELDING

Only approved WPS (Welding Procedure Specification) and consumables shall be employed on the job.

Records of approved PQR and WPS shall be available at site. Welding operators shall carry identity cards describing their qualification.

Coupon plates shall be attached to one end of the longitudinal seam in such a manner that the edges to be welded are a continuation and duplication to the corresponding edges of the seam. Welding shall be carried out in a responsibly continuous operation, by the same process, and by the same welder / operator.

The coupon plates shall be subject to the following tests :

• Tensile test - reduced section tensile test }

• Bend test - face } as per ASME IX

• Bend test - root }

• Impact test - }

Workmanship

All cut edges should be ground to remove the effect of previous shearing, chipping or

flame cutting (in case of cavities, the same shall be built up by buttering, ground flush &

DP tested).

The ends of branch pipes and other openings on the shell shall be ground to a smooth

radius after all welding is completed.

All weld spatters should be ground off and welds used for Temporary attachments of

erection cleats should be ground flush, with plate surface & DP test (Attachments are to

be cut off not closer than 3mm to the parent metal & ground flush with the plate surface).

All precautions shell be undertaken to ensure that the properties of material is not

impaired by the process of fabrication or handling of material during fabrication.

CONSTRUCTION OF CPP, UTILITY & RTF TANKS

METHOD OF CONSTRUCTION

1. CONVENTIONAL - BOTTOM TO TOP

2. JACKING - BUILD & LIFT

CONSIDERATIONS :

• SAFETY

• QUALITY

• SPEED

• ECONOMY

CONVENTINAL METHOD

STEPS

o ERECT BOTTOM PLATES

o ERECT ALLIGN BOTTOM SHELL COURSE

o ERECT SECOND SHELL COURSE

o FIT UP / WELDING AS PER SEQUENCE

o ERECTION / ALIGNMENT / WELDING OF SUBSEQUENT SHELL

COURSES.

SPECIAL REQUIREMENTS

o TEMPORARY STAGING – BRACKETS / SCAFFOLDING JALLIES AT

ALL HEIGHTS.

o WELDING TROLLEYS

o EXTERNAL GUY ROPES

o HEAVY CRANEAGE

DISADVANTAGES

o ALL WORK LIKE ERECTION / WELDING / INSPECTION DRESSING

ETC. AT ALL ELEVATIONS ON TEMP. STAGING.

o HINDRANCE TO EQUIPMENT CRANE MOVEMENT AROUND TANK

DUE TO GUY ROPES.

o VULNERABLE TO DAMAGE DUE TO WIND

SAFETY IN CONSTRUCTIONOF TANKS(CONVENTIONAL METHOD)

I PLANNING

COMPLETE DESIGN / ENGG. BEFORE ERECTION

CONSIDER SEASONS IN COMPLETION

FREEZE CONSTRUCTION PROCEDURE

FINALISE QUALITY ASSURANCE PLAN

II SAFETY ON MEN

SUPERVISION / DISCIPLINE

CUT MANHOLES

STRONG & SAFE WORKING PLATFORMS

ERECTION DERRICK

WELD JIGS / FIXTURES ON GROUND

WELDING TROLLEYS

III SAFETY OF TANK

PROJECT AGAINST WIND

ANCHORS FOR GUY ROPES

STIFFNER RINGS

MOVING ROOF STRUCTURE

SHELL TO BOTTOM JOINT

SAFETY IN CONSTRUCTION OF TANKS(JACKING MEHTOD)

I SAFETY OF MEN

SINCE ALL WORK AT ALMOST GROUD LEVEL, IT IS VERY SAFE

FOR PEOPLE WORKING ON TANKS.

II SAFETY OF TANK UNDER ERECTION

SINCE ALL WIND GIRDERS, STIFFENDERS AND ROOF PLATES

ARE IN POSITION, TANK IS VERY SAFE AGAINST HEAVY

WIND AT ANY STAGE DURING CONSTRUCTION.

III SAFETY OF SURROUNDING TANKS

IF TANKS ARE BEING CONSTRUCTED ADJACENT TO EXISTING

TANKS, SAFETY SCREEN OF ONLY 3 TO 4 MTR HIGH IS ADEQUATE.

SINCE ALL WELDING IS AT LOWER HEIGHT NO POSSIBILIT OF

SPARK FLYING TO ADJACENT TANK.

INTRODUCTION

“Those who do not take lessons from mistakes are destined to repeat History”.

This quote apply outlines the evolution of safety measures. It is with the innumerable accidents, mishaps, loss of lives in the past that various safety precautions and measures have been developed. The purpose of this presentation is to highlight a few of these through safe methods, safe procedure, safe practices to be adopted and rigorously followed during construction of storage tanks so that the ‘History’ does not repeat itself.

When we talk of safety during construction of tanks, it means –

Safety of men at work

Safety of tank under construction.

Safety of adjoining tanks, equipment, property etc.

CONVENTIONAL METHOD OF TANK CONSTRUCTION :

Traditionally, erection of site constructed tanks is done from bottom to top stage wise with each shell course being erected progressively. As the tank construction progress, operating elevations go on increasing requiring men to carry out all works like fitting, welding, inspection etc. at heights.

Further high boom heavy duty cranes are also required for ease of erection. Alternatively erection is carried out at heights using pipe shell derricks and manual / mechanical winches.

On reaching the top level, after completion of erection of all shell courses; roof supporting structure is required to be erected and roof supporting plates are erected thereafter.

This method of construction requires providing temporary staging / scaffolding assembled from brackets, jallis etc. at all elevations and involves movement of these scaffolding rings upwards from one shell course to another during tank construction. This is a very cumbersome and risky operation and usually accidental falls take place during movement of scaffolding.

Subsequently the scaffolding rings are flowered stagewise and tank shell is dressed by chipping / grinding etc.

The tanks during construction require provision of external guy ropes for stability. The guy ropes often cause hindrance to crane movements.

The incomplete tank before erection and fix up of wind girders in floating deck tanks of fixing of roof structure for cone roof tanks are highly vulnerable to collapsing due to wind. Every year a number of tanks collapse during construction due to wind.

When new tanks are required to be constructed adjacent to existing operating tanks containing hydrocarbon products, high barricading screens are required to be provided to protect the adjacent tanks. These screens which are usually very high need special design capabilities for stability against wind and call from heavy foundations.

MODERN CENTRALISED JACKING SYSTEM :

In the modern tank erection method – using Centralised Hydraulic Jacking System the top most shell course is erected first, the roof is then erected all work being done at almost ground level. The top shell course with roof is then jacked up to accommodate the next shell course.

The system use special jacks with self locking jaws moving vertically on trestles. The jacks are provided circumferentially at a pitch of 3M to 4M inside the tank. The jacks are all connected to a centralized hydraulic power pack which cause all jacks to rise in unison by 100mm at a time. Jack retraction is automatic and thus the tank is lifted gradually. A lift of 2 M is generally achieved in 2 hours.

This method of tank construction has tremendous in built safety all work like fit-ups, welding, inspection etc. is carried out at ground level.

The other advantages of Centralised Jacking System can be listed as follows :

1. Heavy Cranage not required.2. Tank safe against wind as top is completed.3. Heights of safety barricades to be provided reduce drastically as all hot work is carried

out at max. 2.5 to 3 M height from required.4. Cumbersome guy ropes, scaffolding etc. not required.5. Tank shell is automatically dressed up before tank is jacked up to receive nest shell

course.6. Excellent dimensional control on tank during construction.7. Saving s in mobilization, tools tackles, jigs, fixtures.8. Saving in Time for tank construction.

This method with revolutionise Tank construction in the country and is useful even for increasing capacity of existing tanks by increasing height to the extent possible as well as for carrying out repairs / replacement of tank shells in the foregoing, planning, safety of men work, safety of tanks under construction when conventional method of tank erection is adopted are discussed.

SAFETY IN CONSTRUCTION OF STORAGE TANKS

USING CONVENTIONAL MEHTOD

1. PLANNING

2. SAFETY OF MEN

3. SAFETY OF TANK DURING CONSTRUCITON

I) PLANNING

Needless to say that safety of men. Tank and adjoining properties begins with proper

planning and setting up the complete procedures for constructions and testing of tanks.

Following recommendations will be useful:

The complete engineering & design of tank viz. diameter, height, shell thickness, roof

structure, nozzle orientation etc. should be completed before taking up actual

construction of tanks. Any change to be incorporated later during construction should be

thoroughly examined and then adopted.

- Special attention should be given to the completion schedule with respect to the

climatic seasons.

- Temptation of design as you build should be avoided.

- The construction procedure to be followed should be jointly detailed out by client

and contractor to cover tools & tackles, jigs and fixtures, lifting equipment, working

platforms, methodology of tank erection etc.

- Some additional fixtures like intermediate stiffeners on tanks, anchor blocks as

outlined subsequently may be incorporated though not specifically called for in the

design codes.

- Strict quality control to be maintained during all stages of tank construction.

- Proper sequence and methodology to be adopted during testing of tanks.

SAFETY OF MEN :

Safety of men greatly depends on proper methodology, proper jigs & fixtures, proper

working platform with railing and strict adherence to safety procedure laid out many a times the

so called ‘Heroes and Dare Devils’ amongst the workmen who pride themselves into not following

the laid out procedures meet with accidents. Given below are some specific guidelines to ensure

safety of men at work during construction of storage tanks by conventional method.

GENERAL :

A competent supervisor should always be present at site. No work should be carried out unless necessary work permits are issued in an operating installation.

MANHOLES :

As soon as the first shell course is erected, the shell manhole openings should be cut out and finished smooth by grinding. This not only facilitates movement of men but also provides access for casualty in case of any accident inside the tank.

LADDERS :

Temporary ladders are required to reach working level platform as the tank construction progress. The ring used for these ladders should be generally 20mm dia and rungs should be 250mm C/C. The welding of the rungs to the shell should be carried out by qualified welder and dully inspected.

It is advisable to start and provide external spiral stairway as the tank progresses.

WORKING PLATFORMS :

All the fixtures used for fabrication of temporary working platforms i.e. clamps brackets, jallies should be made of good quality materials. Should be good condition and of STANDARDISED design. In case such material is reused, special attention should be given to recondition these fixtures by removing old weld tank and weld deposits.

The working platforms must be provided with brackets and clamps over the jallies with hand-railing all around.

A typical design of working platform is attached. This design not only provides a safe and sound temporary working platform but also provided stiffness to the tank shell to withstand moderate winds.

ERECTION DERRICK :

Whenever Cranes are not available, usually a light weight and short pipe derrick (4” dia B class Pipe) clamped on to the shell is used to lift shell courses progressively. It is strongly recommended that at lease two guy topes (8 – 10 mm dia) with turn buckles should be provided inside the tank to prevent the derrick from toppling over with the load.

WIREROPES :

For lifting plates shell construction, suitably sized steel wire ropes should be used with a manual or automatic winch. Use of manila ropes and manual hoisting should be discouraged.

FIXING OF ERECTION JIGS & FIXTURES ON GROUND :

With planned erection work, all jigs and fixtures required to fixed on the tank shell like horseshoe clamps for erection channels on horizontal joints, horseshoe clamps for special fixtures for vertical joints, shell clamps for temporary working platform, lifting lugs should be welded onto the shell plates on ground before these are lifted for erection in position.

This not only ensures that good quality of welding is achieved for these fixtures but also results in faster shell course erection by eliminating welding of fixtures in situ.

WELDERS TROLLEYS :

Light weight welders trolleys moving over the entire circumference of newly erected shell to carry out all shell joint viz. horizontal and vertical from outside should be provided with proper strong bottom, railing cage and roller bearings for the wheels. All welding trolleys must be inspected by TEC/PMC-I Safety Engineers.

III SAFETY OF TANK DURING CONSTRUCTION :

ROUNDATION :

Storage tanks are constructed over sand pad foundations which are most economical. The settlement of tank depends not only on the quality of materials used but also on the quality of compaction achieved during construction of foundation.

The levels should be checked recorded before tan bottom plates are laid on the foundation.

PROTECTION AGAINST WIND :

Unfinished tanks without stiffeners and before the roof structure is erected are highly prone to collapse during high winds.

High velocity winds passing over the tank diameter cause partial vacuum inside the tank (Educator effect) and this coupled with external force in the direction of the wind causes the shell to collapse either partially or fully into most awkward shapes.

Please note that for a cone roof tank under construction without roof structure erected, the curb angle provides virtually no protection against wind.

This is not only a safety hazard to personnel working inside the tank but also requires extremely cumbersome, time consuming and expensive repairs.

Some methods suggested to prevent such accidents are presented below :

ANCHOR BLOCKS FOR GUY ROPES :

Plan and provide concrete anchor blocks around the tank to provide anchorage for external guy ropes to be provided during tank erection. The external guy ropes may be provided from top of the completed shell through special sliding fixture that is locked in position with two taper wedges in opposite direction. Such fixture are easy to remove and install to facilitate welder trolley movement whenever employers.

STIFFNER RINGS :

During engineering stage provide intermediate stiffner rings all along circumference either internally or externally to suite erection convenience. Simple rings fabricated from angles (fixed with flange out) and provided at shell sections where thickness reduce to 8 mm and below provide substantial stiffness to the completed shell.

PAINTERS TROLLEY :

A fabricated T section stiffener ring can be provided inside the tanks on the top shell course internally or externally. This provides an excellent track for painters trolley from which sand blasting / painting can be done safety and economically as the expensive temporary scaffolding not required. All painting trolleys must be inspected by REAL Safety Engineers.

MOVING ROOF STRUCTURE :

This is a innovative method adopted for cone roof tanks with self supported roof.

- The entire principle roof supporting structure trusses / members are prefabricated and stored on bottom plates before bottom shell course is erected.

- After erection of 3/4 shell courses, the roof structure is assembled and completed on the bottom of the tank.

- As the tank height progresses, the roof structure is lifted up gradually on stage using chain pulley blocks and is temporarily locked on to the shell.

- The roof structure virtually follows the shell erection as the height of tank increases. This provides substantial protection to the tank as against wind during construction.

SHELL TO BOTTOM JOINT :

During erection of shell courses, it is strongly recommended that stiffeners (ISA 65 X 65 X 6

150 high) should be provided bottom internally at a pitch of 1 to 1.5 M all along the

circumference.

This is offers stiffness to the bottom course and may reduce the extent of damage due to

wind.

***********

HYDRAULIC JACKING SYSTEM

INSTRUCTION FOR SMOOTH OPERATION :

PLEASE :-

a) Ensure that after laying the Tank Bottom Plates, a gap of minimum 450mm is created

between the Top shell course with roof structure and bottom plate of the tank in order to

maneuver the movement of material.

b) Set the Jacks in same level with reference to the bottom plate of the tank.

c) Check the clearance between Jaws & Square Bar for smooth sliding.

d) Release the Jaws fully by operating release handles before engaging Jacks in Trestle

columns.

e) Loosen the Fastners in the release plate, Check the spring buckling and loosen Jaw

fastners to confirm movement.

f) Follow the sequence of operation either for Tank Construction or for dismantling as per

procedure given separately.

g) I) Check periodically the Hydraulic System for Leakage.

II) Check the Oil level in Tank / Reservoir.

III) Check the direction of Hydraulic Pump Motor.

IV) Check the Air leakage in the system, if any, appearing in the form of Hydraulic Oil

Foam.

In case of such leakage’s are found, tighten all the joints once again properly.

h) I) Check the pressure relief valve and its setting, if pressure drop is found in the

system.

II) Check the direction control valve (Toggle Level Type) for direction of operation.

HYDRAULIC JACKING SYSTEM

PROCEDURE FOR LIFTING OPERATION OF HYDRAULIC JACK :

PLEASE :-

1. Design the number of jacks to be used in the system by considering the total weight of the

Tank excluding Bottom plate, and ensuring that spacing between two successive Jacks does

not exceed the distance of 3 to 3.5 meters on the periphery.

2. Install all the jacks at equal space circumference.

3. Ensue that the load is on ht jacks after they are installed.

4. Operate upper Cam levers and open all upper Jaws.

5. Open all the Jack valves.

6. Pressurise the power pack. All jacks (upper Jaws being open) will quickly open fully with shell

course just sliding up by 100mm.

7. Keep the system either pressurized or close the power pack main valve tightly.

8. Close all the jacks valves and then depressurize the system.

9. Check that jack movements for all the assemblies are uniform.

If movement is not uniform in some of the assemblies pressurize the system once again.

10. Open the valves for all jack assemblies and depressurize the system, so that the cylinders

will retract to the original positions in upward direction.

11. Repeat the procedure for each stroke of 100 mm till such time, height equal to one shell

course is achieved.

12. CAUTION : It is essential that the power pack safety set valve is set for adequate pressure so

as to lift between 120/150 Bar. This will ensure that the power pack in ‘ON’ continuously

without undue pressure and leakage’s / ruptures.

13. Extra nos of jack in working condition shall be available in case of failure while lifting.

HYDRAULIC JACKING SYSTEM

PROCEDURE FOR LOWERING OPERATION OF HYDRAULIC JACK :

PLEASE :-

1. Decide the number of jacks to be used in the system by considering the total welding of the

tank excluding bottom plate and ensuring that spacing between two successive jacks does

not exceed the distance of 4 to 4.5 meters circumferntially.

2. Install all the jacks at equal space circumferntially.

3. Ensure that the load is on the jacks after they are installed. This means jacks are fully closed

and load is on upper jaws.

4. Ensure that the lower jaws are free. Operate lower can levers and open all lower jaws.

5. Open all the jacks valves.

6. Pressurise the power pack. All jacks (lower jaws being open) will quickly open fully with

course (shell) just sliding up to 100mm.

7. Keep the system either pressurized or close power pack main valve tightly.

8. Close all the jack valves and then depressurize the system.

9. Check the jack movement for all the assembles in uniform.

If movement is not uniform in some of the assemblies pressurize the system once again.

10. Open the valve for all jack assembles and depressurize the system so that, cylinders will

retract to the original position in Downward direction.

HYDRAULIC JACKING SYSTEM

SCHEDULE OF MAINTENANCE FOR HYD. POWER PACK

PREVENTIVE MAINTENANCE :

PLEASE :-

a) Check the level in the Power Pack (Hydraulic) through the Oil level indicator.

b) Lubricate the Rotating parts daily, after cleaning the Lubrication Points.

c) Clean the Oil filter, directional control valve, Hose Assembly and ‘T’ joints periodically

(Weekly).

d) Clean the Pump filter & Pump Assembly at the time of changing the Reservoir / sump Oil

(Once in three month).

e) Test and calibrate the valves in the system periodically as per the pressure rating.

PROCEDURES / REPORTS TO BE MAINTAINED AT SITE

- DAILY PROGRESS REPORTS

- WEEKLY PROGRESS REPORTS

- MONTHLY REPORTS

- DOCUMENT TRANSMITTAL FORM

- WPS/PQR QUALIFICATION FORM

- ACCIDENT REPORT

- MANPOWER MOBILISATION SCHEDULE

- EQUIPMENT MOBILISATION SCHEDULE

- RADIOGRAPHY INSPECTION REPORT

- WELDING PROCEDURE SPECIFICATION

- PROCEDURE QUALIFICATION RECORD

- INSPECTION REPORT

- LIQUID PENETRANT EXAMINATION PROCEDURE

- MATERIAL IDENTIFICATION REPORT

- CHECK TEST REPORT

- BILLING STATUS REPORT

- POST WELD HEAT TREATMENT PROCEDURE

- ENGINEERING PROGRESS REPORT

- SEQUENCE OF WELDING

- MAGETIC PARTICLE EXAM PROCEDURES

- RADIOGRAPHY PROCEDURE

- TANK CALIBRATION PROCEDURE

- VACCUM TEST / AIR TEST PROCEDURE

- COLLAPSIBLE TEST PROCEDURE

- HYDRO TESTING PROCEDURE

- FLOTATION TEST / PUNCTURE TEST PROCEDURE

- TANK ERECTION PROCEDURE – CONVENTIONAL

- TANK ERECTION PROCEDURE – HYDRAULIC JACKING

- HYDRAULIC JACKING PROCEDURE

- BLASTING & PAINTING PROCEDURE

- WPQR-WELDER PERFORMANANCE & QUALIFICATION RECORD.

CONTENTS

- MATERIAL

- FABRICATION

- FABRICATION – SEQUENCE OF OPERATIONS

- TESTING, CALIBRATION & PAINTING

1) MATERIAL :

1.1.The material requirement shall confirm to data sheet / drawing of the tank. All Cast Nos, Coll Nos. shall be recorded before cutting and the same shall be transferred on to the cut portion by letter & No. Punchs.

1.2.Plate edges shall be sheared of machine cut, Gas cut plates will be ground to weld joint profile as per drawings. Pug cutting machine shall be used. Hand cutting to be avoided as far as possible.

1.3.Plates shall be measured diagonally to ensure rectangularity.

1.4.All formed plates will be numbered with paint on the concave side as per construction drawings.

2) FABRICATION :

2.1. Shell plates shall be cut and rolled to form mean diameter circumference correctly, i.e. equal to (I.D. of shell + thickness of individual course) x 3.1416. No allowance for gaps in vertical joints shall be made while cutting plates and developing circumference. Length shall be as per above formula. This will ensure correct circumference after welding of verticals, considering welding shrinkage’s.

2.2. Shell plates alignment limits will be within those allowed by codes. Misalignment uncompleted vertical joints shall not exceed 10% of the plates thickness or 1.5 mm for plates 20 mm thick and under 3 mm for plates over 20 mm thick which ever is larger.

Plumbness : The maximum “out of plumbness” of the top of shell relative to the bottom of shell, shall not exceed 1/200 of the total tank height. In completed horizontal butt joints the upper plate shall not project beyond the face of the lower plate by more than 20 % of the thickness of the upper plate with a maximum of 3 min except that a projection of 1.5 mm is permissible for upper plates less than 8 mm thick.

2.3. Vertical shell joints should be offset by at least 1000 mm or by a distance of 5t, ‘t’ being the plate thickness of thicker shell course, whichever is maximum.

2.4. First shall course plates shall be arranged so that the vertical joints clear the annular ring welds or sketch plate welds by at least 300 mm. Nozzle weld … reinforcement pad welds shall also clear vertical joints as per codes.

2.5. No holes shall be made in shall plates for lifting purposes.

2.6. Top curb angle shall be “lap welded” to the top shell course with” the flange turned outside”

as per data sheet. (as per drawing)

2.7. Roof laps shall be as per approved drawing and laps shall be arranged with the lower edge of

the upper plate underneath the upper edge of the lower plate.

2.8. Shell welding : All vertical and horizontal shell joints will be welded from both sides for full

penetration. Root pass welded from outside of the tank shall be thoroughly cleaned by

grinding / gouging / chipping, before laying sealing pass from inside the tank. The joints

will be completed by welding from inside tank.

Vertical welds of individual shell courses should be welded first before

fitting & tacking the horizontal joints. This is to minimize shell warpage and allow

weld shrinkage’s so that a circumferential ring of correct circumference results. Welder’s

initials / code number shall be painted / stamped on the welding done by him.

Following electrodes are recommended for tanks welding job :

a) Low hydrogen electrodes shall be used for all manual metal Arc welds of shall course

having a thickness of 12mm or more and for attachment of shell course to bottom or

annular plates.

b) For all other weldings, high cellulose / rutile type electrodes as per AWS classification

SFA 5.1 acceptable.

c) Electrodes shall confirm to REAL/NESC CONSULTANT) approved list of electrodes.

INSPECTION :

a) Inspector shall ensure that only tested welder as per ASME pressure Vessel Code

Section –IX are permitted to carry out welding including tack welds made for joint

alignment.

b) Welder shall be qualified by REAL/NES shall be 100% Radiography of test coupon.

Verify the brand names of electrodes as per AWS classification SFA 5.1

TANK FABRICATION – SEQUENCE OF OPERATIONSFOR CONE ROOF TANKS BY JACKING METHOD

3.0.TANK FABRICATION :

3.1.Before laying plates, levels should be noted down. Lay prepainted annular plates. Complete

ring by tack welding. Mark circumference circle by punch mark.

3.2.Lay prepainted sketch plates and tack weld.

3.3.Weld annular plate joints.

Inspection : Spot radiography annular butt joints.

3.4.Mark positions of trestles / hydraulic jacks.

3.5.Fix elevators at 450 mm height at equal spacing.

3.6.Erect second shell course from top on elevators and weld all vertical joints except make up

plates then cut make up plate of required length and weld vertical joints.

3.7.After vertical welding the verticality of the tank, roundness and dia should be recorded. Weld

second shell course verticals as per sequence. Inspection : Radiograph as per code.

3.8.Erect top shell course and weld all vertical joints except make up plates then cut make up

plate of required length and weld vertical joints.

3.9.After horizontal welding before radiography shell verticality should be recorded and the same

shall be within code limits.

# Level readings are to be recorded before erection of each shell # No. key plates are to be

used whilst fitting the horizontal joint.

Inspection : Radiograph as per code.

Note circumference before welding and after welding. Check peaking and banding.

Check verticality. This inspection to be repeated at each horizontal joint.

3.10. Install scaffolding ring on the outside. 660 mm from top to facilitate curb angle and wind

girder fitting and welding.

3.11. Install curb angle.

3.12. Erect roof structure.

3.13. Weld curb Angle.

3.14. Complete welding of roof structure.

3.15. Erect wind girder on gussets on Sc 5 & Sc 4 as per drawing. Weld all radial joints first to

complete ring & then weld Wind Girder to shell.

3.16. Weld bottom sketch plates as per sequence-leave sketch plates to annular ring welds.

3.17. Lock annular ring and sketch plate with horse shoe clamps and tack weld.

3.18. Install roof plates on structure and weld. Weld installation support structure on the roof

plates.

3.19. Dismantle outside scaffolding.

3.20. Initiate ladder steps from top. Install roof nozzles and roof failing etc. Complete touch up

painting from inside / outside.

3.21. Install Hydraulic jacks on trestles as per drawing Ensure vertical shell joints are clear of

trestles.

3.22. Dress up Lift Assembly for shell course No.

3.23. Erect SC# 3 on elevators. Align with erection channels and pipe turn buckles.

3.24. Weld verticals of Sc # 3.

3.25. Lower assembly on Sc # 3 and align horizontal joint of Sc # 3 & Sc # 4.

3.26. Weld horizontal between Sc # 3 and Sc # 4.

3.27. For Sc # 5 to 2, repeat similar operation of Sc # 3 as explained in 3.22 to 3.25.

3.28. Lift assemble and remove elevators. Elect Sc # 1 Leave make up piece but provide

stiffeners.

3.29. Complete vertical welding on Sc # 1.

3.30. Match bottom annular ring & match Inside Diameter (I.D.)

3.31. Lower assembly on Sc # 1. Complete Horizontal fit up and welding. Remove hydraulic

jacks / trestles.

3.32. Fit up shell to bottom joint. Check levels and correct by installing shims / plates under

annular ring.

3.33. Weld inside shell to annular plate fillet weld joining first. Inspected by penetrating oil.

3.34. Weld annular ring to sketch plate, taking care to provide proper jig to avoid any distortion.

3.35. Complete out side shell to annular plate fillet weld.

3.36. Weld make up piece.

3.37. Check Bottom plate welds by vacuum box.

3.38. Hydrotest the tank.

TANK FABRICATION – SCHEME OF OPERATIONS

FOR FLOATING ROOF TANKS CONVENTIONAL METHOD

4.0.TANK FABRICATION :

4.1.Lay prepainted annular plates, complete ring by tack welding mark circumference circle by

punch mark. Annexure-I.

4.2.Lay prepainted sketch plates and tack weld. Attachment-I.

4.3.Weld annular plate joints.

4.4.Erect shell course No. 1 and No. 2 (Sc # 1 & Sc # 2) leave make up piece but provide

stiffeners on Sc # 1.

4.5.Weld No. 1 vertical and No. 2 verticals as per sequence.

Inspection : Radiograph as per code – attachment-II.

4.6.Align horizontal joint of No. 1 and 2 AND WELD Attachment-II.

Inspection : Radiograph as per code.

Note circumference before welding and after welding. Check peaking and banding.

Check vertically. This inspection to be repeated to each horizontal joint.

4.7.For Sc # 3 to 9 repeat similar operation of Sc # 1 & 2 as explained in 4.4 to 4.6.

4.8.While erecting the shell course Sc # 3, 5 & 9. erect wind girder as per drawing weld radial

joints first to complete ring & than weld wind girder to shell.

4.9. Install curb angle.

4.10. Weld curb angle.

4.11. Shift deck plate from make-up piece of Sc # 1.

4.12. Make temporary staging made out of angle 50x50x6 300 mm high. Lay deck plate.

Fabricate pontoon as per fabrication drawing. Complete painting from inside.

4.13. Fix leg supports & guide Nozzles on the deck.

4.14. Weld make up piece.

4.15. Fix Nozzles on the shell.

4.16. Initiate ladder steps from top.

4.17. Erect rolling ladder & track.

4.18. Check bottom plate welds by vaccum box.

4.19. Hydro test the tank.

4.20. Fix seal assembly.

4.21. Start draining the water checked movement of deck.

ATTACHMENT – I

BOTTOM PLATE PREPARATION

I) ALLIGNMENT :

Mark the circumference to the tank by chalk powder, set center plate to four center line targets using wire or code.

II) LAYING :

Lay annular plates. Complete ring by tack welding. Overlap and tack bottom plates working from center to outer edge. Use cleats and taper wedges for aligning. Temporary fixures to be welded from on side so that they can be easily removed. Tack weld short seams and lightly tack weld long seams.

III) WELDING :

Mark three concentric circles of diameter ‘D”, D/3 and 2D/3 with center punch dividing bottom plates in three concentric areas, inner most circle being area No.1. Joints in area No. 1 are to be welded first, followed by the joints in area 2 and area 3. All short seams must be completed before welding long seams. Weld long seam joints working from center to outer edge in all the four directions. Only one plate should be welded at a time.

Detailed welding sequence shall be prepared based on bottom plate layout.

ATTACHMENT II

1. VERTICAL WELD :

After tack welding divide the length of the weld in 4 equal lengths, start No. 1, welding which is the topmost from bottom upwards. Grind of the start of zone (1) welding to receive the finish of zone (2) Commence zone (2) welding to receive the finish the zone (3) welding Repeat the process till zone (3) and zone (4) welding is complete. Alignment of the joint to be made with 4 Nos. of castorix plates.

2. HORIZONTAL WELDS :

Three to four welders should complete shell horizontal weld operating in the same direction. Start of each welding to be ground to receive finish of succeeding weld.

Use cleats and laper wedges and erection channels for aligning. Temporary fixtures to be tack/stitch welded from on side so that they can be easily removed.

ATTACHMENT-III

1) HEATING COIL :

Heating coil shall be pressure tested as per approved Engineering Drawing.

2) NOZZLE REINFORCEMENT PLATE :

Nozzle Reinforcement Plate be pneumatically tested at 1.05 Kg/cm2 with soap solution. This test shall be carried out before filling the tank for Hydrostatic Testing.

3) HYDROSTATIC TEST :

Before Hydrotest, all welded lugs, cleats and brackets used for erection purposes shall be carefully removed from inside and outside the tank. Weld attachments shall be ground smooth and MPI tested.

The filling height, incase of fixed roof of open roof tanks, shall be up to the curb angle and in case of floating roof tanks, it shall be restricted to the maximum height so that weather shield does not go beyond curb angle.

Filling of the tank shall be in 4 stages, 25%, 50%, 75% and 100%. After each stages load stabilization period shall be observed as follows :

- 24 hours between each stage for tanks with a capacity equal or more then 10,000 Cu.M.- 12 hours (Min) between each stage for tanks with a capacity under 10,000 Cu.M. During this period tank settlement reading swill be recorded till steady valves are obtained before further filling is allowed.

During this period tank settlement readings will be recorded till steady valves are obtained before further filling is allowed.

For tank settlement readings there should be minimum 8 readings for small dia tanks (up to 25 Mtr. Dia) and 12 readings for bigger dia tanks.

Filling rate shall not exceed 5 MWC per day. If sea water is used for testing and is to emain in the tank for more than 30 days, and oxygen scavenger and corrosion inhibitor shall be added to the sea water.

When the tank is full with water, all the welded joints shall be hammered (21 Bs Nylon) and to observe any leaks. All weld repairs shall be done with water level min 300 mm below the joint being repaired.

After testing the tank, water shall be drained at a maximum rate of 5 MWC per day. Check that roof nozzles are open while draining to avoid vacuum collapsing of the tank. The tank shall be thoroughly flushed with clean fresh water. Standing water silt or other dut left in the tank after hydrotesting shall be thoroughly cleaned.

CAUTION :

Utmost care should be taken while pneumatically pressurizing the tank. If necessary a safety valve with correct set pressure shall be installed on the pressurizing line.

FIXED ROOF TEST :

After filling the tank up to curb angle, all openings in the roof shall be closed and internal pressure shall be applied equivalent to the weight of roof plates, all welded joints in roof shall be checked with soap-suds for detection of leaks. For tanks with small internal pressure, the test pressure shall be equal to 1.25 Design pressure.

4) CALIBRATION & PAINTING :

I) CALIBRATION :

Strapping and calibration of all tanks shall be done in accordance with API-650.

II) PAINTING :

Before application of paint, the surface shall be cleaned of dust etc by wire brushing / sand blasting by SA 2 for under side for Bottom Plate & SA 2 ½ for Shell, Roof, Deck etc.

All paints shall be stirred up not be carried out if the atmospheric temperature is more than 5 Deg. C. above Dew or if the temperature exceeds 40 deg. C. in the shadow or if relative humidity exceeds 85% or any other adverse weather conditions such as rain, fog, dust storm etc.

Coating media shall be applied in uniform thickness. All slots, recesses, grooves, corners, angles and interstices shall be distributed or removed and new paint shall be applied uniformly. All paint containers shall only be opened prior to utilization and shall be carefully closed immediately after withdrawal of material. Material which become unserviceable during storage shall not be applied. All painting material shall be kept in weather proof barracks and shall be kept cool and dry.

Paint shall be applied by brush or by spray. During spraying the paint shall be maintained thoroughly mixed in the spray gun.

The paint shall be sprayed uniformly. Surface impossible to be coated by spraying shall be painted by brush.

Painting work shall be done in day time only.

Tank number and capacity shall be painted on each tank with suitable size letters and numbers.

INSPECTION :

Check dry film thickness (DFT) with standard paint thickness measurement instrument such as Elcometer.

DWAWING / DOCUMENT – CONTROL PROCEDURE

1) All drawing / document to be received from client / consultant will be received by Site -

Incharge & a register will be maintained indicating all details including date of receipt.

A copy of all the drawings & Documents received at site will be sent to Mumbai Office for

reference, record / action (if any).

2) All drawings / documents to be prepared by Artson shall be submitted to REAL/NES

Artson’s Mumbai Office with a copy of cover letter to REAL/NES/AEL at site for

information.

Only finally approved drawings copies (3 Sets) will be sent to Artson’s Site incharge

(Bank Format for forwarding drawing is enclosed). Out of these, one copy will be given to

concerned work engineer & one copy to inspection engineer. One copy will be kept at site

as Master copy.

3) Any charge in drawing the due to site requirements will be incorporated in drawing by

joint signature of AEL & NES /REM representatives at site. This change will be intimated

in writing in Mumbai Office for incorporation in tracing.