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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
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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 PREPARATION SIS 055900 & SPEC. NO.
25194-3PS-GAW
005-REV.02
SA 2 FOR UNDER SIDE OF BOTTM PLATE,
SA 2 FOR SHELL, ROOF , DECK ,ETC.
(SWEEDISH STANDARD)
B) PAINTS APPLICATION AS PER PURCHASER REQUIREMENT
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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 AELS 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
AELS General Manager and consultants 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.
Fiance
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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 clients 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.
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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 consultants
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 consultants 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.
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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, clients specific requirements shall be conformed
to.
Conformance shall be checked at pre-order, receipt, inspection
and in-process stages.
All materials shall be bear manufacturers markings and shall
co-relate with Mill Test Certificates. Markings shall be
transferred to cut pieces with consultants 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.
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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.
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CONSTRUCTION OF CPP, UTILITY & RTF TANKS
METHOD OF CONSTRUCTION
1. CONVENTIONAL - BOTTOM TO TOP
2. JACKING - BUILD & LIFT
CONSIDERATIONS :
SAFETY
QUALITY
SPEED
ECONOMY
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CONVENTINAL METHOD
STEPS
o ERECT BOTTOM PLATESo ERECT ALLIGN BOTTOM SHELL COURSEo ERECT
SECOND SHELL COURSEo FIT UP / WELDING AS PER SEQUENCEo ERECTION /
ALIGNMENT / WELDING OF SUBSEQUENT SHELL COURSES.
SPECIAL REQUIREMENTS
o TEMPORARY STAGING BRACKETS / SCAFFOLDING JALLIES AT ALL
HEIGHTS.
o WELDING TROLLEYSo EXTERNAL GUY ROPESo 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
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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
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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.
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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.
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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.
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SAFETY IN CONSTRUCTION OF STORAGE TANKSUSING CONVENTIONAL
MEHTOD
1. PLANNING
2. SAFETY OF MEN
3. SAFETY OF TANK DURING CONSTRUCITON
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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.
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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.
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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.
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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.
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- 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.
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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 leakages 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.
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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 leakages / ruptures.
13. Extra nos of jack in working condition shall be available in
case of failure while lifting.
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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.
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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.
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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.
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CONTENTS
- MATERIAL
- FABRICATION
- FABRICATION SEQUENCE OF OPERATIONS
- TESTING, CALIBRATION & PAINTING
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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 shrinkages.
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.
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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 shrinkages so that a
circumferential ring of correct circumference results. Welders
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
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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 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.
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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
Artsons 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
Artsons 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.