DOCUMENT CODE 19 - صفحه اصليdigilib.monenco.com/documents/10157/4214663/SP-41-01.pdf · DOCUMENT CODE NO. OF PAGES: 19 ... A live load of 1200N/m2 ... and inaccessible bottom

NIOEC-SP-41-01(1) DOCUMENT CODE NO. OF PAGES: 19

PLAN/PRJ/SUB UNIT PHASE DISCIPLANE DOCUMENT TYPE SERIAL NO. REV. NO. DATE

NIOEC 000 EG ME SP 4101 A2 FEBRUARY, 2007

NATIONAL IRANIAN OIL REFINING & DISTRIBUTION COMPANY

NATIONAL IRANIAN OIL ENGINEERING

& CONSTRUCTION COMPANY

NIOEC SPECIFICATION

FOR

STORAGE TANKS FIELD ERECTED

FIRST EDITION

FEBRUARY, 2007 THIS SPECIFICATION IS THE PROPERTY OF NATIONAL IRANIAN OIL ENGINEERING & CONSTRUCTION COMPANY. IT IS CONFIDENTIAL AND ALL RIGHTS RESERVED TO THE OWNER. NEITHER WHOLE NOR ANY PART OF THIS DOCUMENT MAY BE DISCLOSED TO ANY THIRD PARTY, REPRODUCTED, STORED IN ANY RETRIEVAL SYSTEM OR TRANSMITTED IN ANY FORM OR BY ANY MEANS WITHOUT THE PRIOR WRITTEN CONSENT OF THE NATIONAL IRANIAN OIL ENGINEERING & CONSTRUCTION COMPANY

FEBRUARY, 2007 NIOEC-SP-41-01(1)


REVISION INDEX

REV. PAGE

1 2 3 4 5 REV. PAGE

1 2 3 4 5 REV. PAGE

1 2 3 4 5 REV. PAGE

1 2 3 4 5

1 X 26 51 76

2 X 27 52 77

3 X 28 53 78

4 X 29 54 79

5 X X 30 55 80

6 X 31 56 81

7 X 32 57 82

8 X 33 58 83

9 X 34 59 84

10 X 35 60 85

11 X 36 61 86

12 X 37 62 87

13 X 38 63 88

14 X 39 64 89

15 X 40 65 90

16 X 41 66 91

17 X 42 67 92

18 X 43 68 93

19 44 69 94

20 45 70 95

21 46 71 96

22 47 72 97

23 48 73 98

24 49 74 99

25 50 75 100

NOTES: 1) THIS SHEET IS A RECORD OF ALL REVISIONS TO THIS SPECIFICATION.

2) REMARKS RELATED TO EACH REVISION SHOW A BRIEF DESCRIPTION. THESE REMARKS SHALL BE INTERPRETED IN CONJUNCTION WITH THE REVISED TEXT MARKED BY REVISION NUMBERS.

3) WHEN APPROVED EACH REVISION SHALL BE CONSIDERED AS A PART OF THE ORIGINAL DOCUMENT.

4) NUMBER OF PAGES EXCLUDES THIS SHEET AND THE COVER SHEET.

4 3 2 FEBRUARY, 2007 M.R.FARZAM - M.R.FARZAM M.A.A.SAJEDI

1 SEPTEMBER 2006 SH.GASEMI - M.R.FARZAM M.A.A.SAJEDI

0 JULY, 2005 K.FARROKHI M.H.ZAKER M.R.FARZAM M.A.A.SAJEDI

REV. DATE PREPARED CHECKED APPROVED AUTHORIZED


CONTENTS PAGE NO 1. SCOPE............................................................................................................................... 2 2. REFERENCES................................................................................................................. 2 3. UNITS................................................................................................................................ 3 4. DEFINITIONS & TERMINOLOGY............................................................................. 3 5. DESIGN............................................................................................................................. 3 6. MATERIALS.................................................................................................................... 6 7. APPURTENANCES & ACCESSORIES....................................................................... 6 8. CORROSION ALLOWANCE........................................................................................ 9 9. TOLERANCES ................................................................................................................ 9 10. FABRICATION & ERECTION-GENERAL.............................................................. 10 11. WELDING ...................................................................................................................... 10 12. TESTING AND INSPECTION..................................................................................... 13 13. DRAWINGS ................................................................................................................... 14 14. INFORMATION TO BE SUPPLIED WITH PROPOSAL ....................................... 14 APPENDIX I........................................................................................................................... 16

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1. SCOPE

1.1 This NIOEC Specification covers the design, materials, fabrication, erection, inspection and testing of welded steel storage tanks in accordance with API standard 650.

1.2 Specification sheets describing individual tanks and appurtenances form part of this

Specification. 1.3 Tanks will be erected at the site proposed by NIOEC. 1.4 Tanks will be erected on asphaltic concrete pads designed and built in accordance

with NIOEC-SP-00-04. 1.5 Process requirements will be given on the Data Sheet by the Purchaser and shall be

complied by the Vendor. A blanked one is attached in Appendix I. 1.6 Order of Precedence

In the event of a conflict among the various documents, the order of precedence shall be as follows: - The purchase order (including attachments) and variations thereon. - The Data Sheets and drawings. - This Specification. - API 650 “Welding steel tanks for oil storage”. If conflict is discovered between the items listed, it shall be the responsibility of the Vendor to call attention to the conflict.

2. REFERENCES

Throughout this Specification the following dated and undated standards/ codes are referred to. These referenced documents shall, to the extent specified herein, form a part of this Specification. For undated references, the latest edition of the referenced document (including any supplements and amendments) applies. For dated references, the edition cited applies. The applicability of changes in dated references that occur after the cited date, shall mutually be agreed upon by NIOEC and the Vendor/Contractor. API (AMERICAN PETROLEUM INSTITUTE)

API-650 “Welded steel tanks for oil storage” API-2000 “venting Atmospheric & low pressure storage tanks”.

ASME (AMERICAN SOCIETY OF MECHANICAL ENGINEERS)

ASME Sec. VIII Div. I “Rules for construction of pressure vessels”

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NIOEC-SP (NIOEC SPECIFICATIONS) NIOEC-SP-00-01 “NIOEC Specification for Civil Design Criteria” NIOEC-SP-00-04 “NIOEC Specification for Foundation for Tanks” NIOEC-SP-00-10 “NIOEC Specification for Units” NIOEC-SP-00-11 “NIOEC Specification for Site Conditions” NIOEC-SP-00-50 “NIOEC Specification for Design criteria for process

& mechanics” NIOEC-SP-41-06 “NIOEC Specification for Large Welded Low Pressure

Storage Tanks” NIOEC-SP-50-04 “NIOEC Specification for Piping Material Specification” NIOEC-SP-80-02 “NIOEC Specification for Painting”

UBC (UNIFORM BUILDING CODE)

Edition 1997

3. UNITS

International system of units (SI) shall be used in accordance with NIOEC-SP-00-10, unless otherwise specified.

4. DEFINITIONS & TERMINOLOGY

4.1 “Employer” means: “National Iranian Oil Engineering & Construction Company”. (NIOEC)

4.2 “Purchaser” means: “National Iranian Oil Engineering & Construction Company”.

When quoted in this Specification as part of a direct purchase order by NIOEC and “Contractor” where this Specification is part of contract documents.

4.3 “Vendor” means: The manufacturer from which the equipment is to be purchased. 4.4 “Fabricator” means: The Company which is responsible for the fabrication of the

tank at site. 4.5 “Erector” means: The Company which is responsible for the erection of the tank at

site. 4.6 “Contractor” means: The person, firm, company or consortium whose tender has

been accepted by the Employer or legal successors in title to such person.

5. DESIGN

5.1 Design Data

5.1.1 Design wind load:

- Earthquake load shall be in accordance with clause 4.1.9 of civil design criteria NIOEC-SP-00-01 & API 650.

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- Wind load shall be in accordance with Chapter 16 of U.B.C. as following:

1) Basic wind speed & exposure coefficient at site as per NIOEC-SP-00-11 & API 650. 2) Design wind pressure shall be in accordance with the chapter 16 of

UBC Vol. 2, Division III.

5.1.2 Design rainfall intensity:

The Vendor shall design the tanks for the rainfall intensity as specified on site condition except for open top floating roofs. For this type of roof, with the deck at its low position at operating level with drain valve(s) closed and, assuming no pontoon compartment is punctured, the deck support legs shall be designed to support the greater of the following loads:

1. Rainfall of 250mm of water uniformly distributed all over deck 2. A live load of 1200N/m2

5.1.3 The snow load shall be considered as per NIOEC-SP-00-11 “Site Conditions”. 5.1.4 Maximum allowable soil bearing pressure shall be specified for the site.

5.2 Low pressure storage tanks such as those in utility service shall be designed in

accordance with NIOEC-SP-41-06. 5.3 Capacities given for individual tanks include allowance for freeboard vapor space

and inaccessible bottom and no further allowance is required in establishing tank size. Capacity of floating roof tanks is the net volume to under side of the roof deck with seals in full operation. Any deviations from this Specification or from API 650 and its appendices shall be clearly stated and shall receive the written approval of NIOEC.

5.4 The design metal temperature shall be the lower of the lowest one day mean ambient

temperature plus 8ºC and the minimum temperature of the contents. The mean temperature is defined as one half of the sum of maximum temperature and minimum temperature.

5.5 Tank overall height and diameter shall be specified. Tank height shall be 14.63m (48

feet) for tanks 4,800 m3 and larger nominal capacity shall be defined by overall dimensions.

5.6 For tanks specified with conical roofs, Vendor may quote an alternate for supplying

a self-supporting dome or umbrella roof where feasible and a cost saving can be made.

5.7 Vendor shall submit initial calculations, materials, sizes, weights, preliminary

sketches and thicknesses for all tanks with his quotation. 5.8 When calculating for vacuum conditions during lowering of tank product in fixed

roof tanks maximum gravity transfer conditions should also be considered.

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5.9 Vendor should quote on type of floating roof specified on tank Specification sheets. Alternate designs may be submitted for consideration.

5.10 The top angle shall be fabricated with the horizontal leg outwards. 5.11 Protective plates shall be installed for roof supports and on any other appurtenances

that could strike the bottom. All plates or clips resting directly on the tank bottom shall be completely seal welded to the bottom with full fillet welds.

5.12 Centre area of floating roof with single deck shall be properly stiffened when tank

size requires it. 5.13 Storage tanks shall be provided with earthling connections. Tanks up to 30m

diameter shall have two earthling connections. Tanks over 30m diameter shall have three earthling connections. Each earth connection shall have sufficient cross section to earth the whole tank and shall not be less than 35mm2. A typical detail of earthling is shown in figure below.

TYPICAL DETAIL OF EARTHING BOSS

5.14 Stress relieving of storage tank plates needed shall be made as necessary for the particular material used. After welding on of appurtenances. The weldment shall be stress relieved as required whether at Vendor’s shop or at site as applicable. The temperature and time required for stress relieving shall be given in drawing and Specification.

5.15 The length of earth connection shall be such that no disconnection produced by 18″

tank up lift.

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5.16 Piping should not pass directly, with little or no flexibility, from the tank shell or tank bottom to the ground or to rigid concrete walls, basins, etc.

5.17 Any connection of vertical pipe along the tank shall judged to be rigid should be

replaced by a connection near the shell/roof intersection, coupled with sliding connections or “guides” along the shell wall.

5.18 Stairs and walkways can be solely supported by the tank shell for mitigation

seismic hazard. 5.19 Anchor bolts need to be designed sash that they behave in a ductile manner, both in

terms of force transfer to the shell and pullout from the concrete foundation. 5.20 All bottom and roof plates shall have a minimum thickness of 6 mm (1/4 in.),

exclusive of any corrosion allowance specified by the purchaser 6. MATERIALS

6.1 Material selection for tank plates shall be in accordance with API 650.

Other materials shall be as follows:

Structural Steel ASTM-A-36 Pipes ASTM-A-106 Gr. A Flanges ASTM-A-181 Gr. I Bolting ASTM-A-307 Gr. B

For low ambient temperatures refer to material requirements as laid down in API 650.

6.2 Where connections are made to external piping the material and all other

requirements of the piping class for nozzles bolting gasketing and pipe shall be met as per NIOEC-SP-50-04.

6.3 Mill, chemical analysis and mechanical test certificates are required for bottom and

shell plates, wind girders, pipes and flanges. Roof plates and other materials require mill certificates only.

6.4 Vendor shall provide all materials as specified on the tank and accessories data

sheets required for the complete fabrication of storage tanks. Purchaser will normally supply tank mixer, instrumentation and firefighting attachments such as B.C.F. of foam chambers. Vendor shall make provision for proper attachment of such items.

6.5 All plates and appurtenances shall be new and uncorroded, Vendor shall supply

plates flat or rolled. Unpainted and unblasted as specified in purchase order. 6.6 Vendor shall supply all welding rods required to shop fabricated tank. Consideration

shall be given to Iranian supply of rods where these conform to the materials required.

7. APPURTENANCES & ACCESSORIES

7.1 Vendor shall furnish and install all appurtenances as specified on the individual tank

Specification sheets unless otherwise noted.

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7.2 Tank appurtenances shall be furnished in accordance with the following descriptions

unless otherwise noted:

7.2.1 Roof vents shall be sized in accordance with API Standard 2000: Venting Atmospheric and Low-Pressure Storage Tanks and the requirement as specified in 5.8.

7.2.2 Ground reading automatic tank gauges: Cone roof tanks shall have gauges

complete with enclosed tape and hydraulic seal float and guide wires. All tapes shall be graduated in standard metric system. Float wells shall be provided for automatic tank gauges on floating roof tanks.

7.2.3 Gauge hatches shall be 8”, spark proof self closing type. Hatches must remain

closed during operation of pressure vacuum vent valves. 7.2.4 Draw off sumps and drains shall be in accordance with API Standard 650.

Sumps and draw off pipes shall be furnished by tank fabricator. Draw off should be shell type with 4” nozzles having an internal downtrend ell, unless specified for crude oil tanks on data sheet. Draw offs shall be self draining. Discharge shall be such that draining can be observed. Followings shall be considered for design of water draw of sumps:

a) Storage tanks in hydrocarbon service shall be provided with a minimum of

one water draw off sump for tanks over 6m in diameter and a minimum of two draw off sumps for tanks over 30m in diameter.

b) End of draw off pipe shall be 100mm above bottom of sump. c) Draw off sump shall be fitted so as to clear the lap joints in the bottom plates

and shall not be placed in the annular plate. d) When flush type suction nozzles are used. The maximum size water draw

off connection shall be 6″. e) Water draw off line shall be fitted with non freezing stainless steel trim drain

valve. 7.2.5 Spiral stairways with landing platform shall be grating and provided on all

tanks according to relevant tables of API 650. All members connected to the shell shall be seal welded. On dome & cone roof tanks a handrail shall be provided extending all around the periphery of the tank.

7.2.6 Heating coil or heater nozzles shall be furnished with a 200 mm. Long internal

projection beveled for welding. 7.3 Vendors standard appurtenances for floating roof shall include, but not be restricted

to the following items:

7.3.1 Rim Seals: The space between the outer periphery of the roof and the tank shell shall be sealed by a flexible device that provides a reasonably close fit to the shell

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surfaces. If the sealing device employs steel shoes in contact with the shell, such shoes shall be made from galvanized sheet conforming to ASTM A 924 with a minimum nominal thickness of 1.5mm (16 gauge) and a G90 coating. If uncoated shoes are specified, they shall be made from sheet steel with the thickness and quality specified on the purchase order. An adequate but minimum number of expansion joints shall be provided. Any fabric or nonmetallic material used as a seal or seal component shall be durable in its environment and shall not discolor or contaminate the product stored. API Recommended Practice 2003 should be consulted regarding the possible need for bonding shunts between the roof and the metallic shoes. Provision for such shunts shall be a subject for agreement between the Purchaser and the manufacturer. a. If a tube seal is proposed Vendor is requested to furnish complete tube

description and reference list of similar installations already in operation in Iran.

b. Floating roof sealing device proposed must be approved by the Employer.

7.3.2 Automatic Bleeder Vents shall be used on all floating roof tanks. Sizes will be

specified on Data Sheet. 7.3.3 Each roof shall be provided with an 8” gauge hatch with a tight cap and gauge

well, and gauge platform of the design specified. 7.3.4 Rim vents of annular section shall be provided on floating roof tanks. 7.3.5 Adjustable roof supports for 1.2 m of operating level and 2 m of cleaning level

between the lowest position of the roof and tank bottom unless otherwise specified. The legs and sleeves shall be of ASTM A 53, seamless pipes. The legs shall rest on steel pads welded to tank bottom. The legs shall be notched at the bottom to provide drainage. The legs shall be designed to support the greater of a live load of 120 kgs./m2 or 250mm uniform rainfall load over the deck.

7.3.6 Anti-rotation pipe incorporating a sampling device adjacent to top platform in

all floating roof tanks shall be furnished. 7.3.7 Roof drain pipes in unheated tanks shall be of the flexible type complete with

bronze swing type check valve. They shall be reinforced Neoprene. In particular 4” dia. hoses shall be heavy type to avoid the floating and consequent damaging of the roof and hose itself. The neoprene shall be completely resistant to the product to be stored. Roof drains shall be of the swivel joint drain when tank heaters are installed.

7.3.8 Unless otherwise specified by the Purchaser, the floating roof shall be supplied

with a ladder that automatically adjusts to any roof position so that access to the roof is always provided. The ladder shall be designed for full-roof travel, regardless of the normal setting of the roof-leg supports. If a rolling ladder is furnished, it shall have full-length handrails on both sides and shall be designed for a 4450 N (1000 lbf) midpoint load with the ladder in any operating position. Stairways with landing platform shall be grating.

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7.3.9 One manhole 20” ID minimum is required for each pontoon compartment.

7.4 Vendor shall submit descriptive literature on the pressure vacuum vent valves, swing

lines with appurtenances and floating roof rim seals with his quotation. Integral vacuum breakers and pressure relief valves may be offered if of an acceptable design.

7.5 Hexagon head bolts and hexagon nuts shall be used for all bolting. 7.6 Foundations will be furnished by Purchaser. Bottom slope shall be graded to a crown

at the center with a slope of 25mm per 3000mm (1mm / 120mm).

7.7 Heating coils and associated supports shall be furnished by the tank fabricator. 7.8 Shell manway shall be 24” ID and two shall be fitted to tanks over 30 meters

diameter. 7.9 Cleanout doors shall be fitted to asphalt and crude storage tanks, and in accordance

with API 650.

7.10 A roof man way 20” ID on cone roof tanks and 24” on floating roof tanks shall be fitted. On tanks over 30 meter diameter two shall be fitted. An emergency vent cover shall be fitted to one man way on each cone roof tank.

7.11 Roof nozzles 3” and over shall have reinforcing pads. 7.12 Tank heaters shall be removable tube bundle type unless otherwise specified on

individual tank Data Sheet. Where a heater of the pipe coil type is used, particular attention shall be paid to: a. Mechanical anchoring and arrangement to allow for thermal expansion and

buoyant forces. b. Corrosion allowances. c. Welding details and procedures, and all joints shall be radio graphed. d. To comply with NIOEC piping standards for materials and procedures. Schedule 160 pipe shall be used for all heater coils, whether finned or not.

7.13 Asphalt storage tanks shall be provided with air distribution rings at the bottom of

the tank for mixing purposes. 7.14 Vent screens shall be course mesh to prevent the ingress of solid objects only.

8. CORROSION ALLOWANCE

Corrosion allowances shall be accordance with article 5.2.1 of NIOEC-SP-00-50.

9. TOLERANCES

9.1 Machining Tolerances

9.1.1 Shell

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a) Shell plates shall have dimensional tolerances as follows: On plate width = ±1.5mm On plate length = +1.5mm Difference in diagonals = +3mm

b) Shell plate edges on completion of machining shall be straight. Deviations,

if any, shall not be in excess of ±1mm.

9.2 Erection tolerances

9.2.1 Deviations both inside and outside the tank of shell plate vertical joints from a true circle generated by tank radius, over a 1 m horizontal span centered on the weld, (peaking) shall be within ± 10mm.

9.2.2 Deviations both inside and outside the tank of horizontal joints over a

1m.vertical span centered on the weld, from a vertical line (banding) shall be within ±10 mm.

9.2.3 The actual radius measured at the lower edge of the base course shall be within

±10mm of the nominal radius of the tank. 9.2.4 Out-of plumbness both inside and outside the tank of each single shell course

shall be within ± 10 mm. 9.2.5 The maximum permissible out-of-plumbness at the top of the tank relative to

the bottom of the shell shall not exceed 1/200 of the tank height but not more than 50mm max.

9.3 Roof Tolerances

9.3.1 On floating roof tanks, the roof seals shall contact the shell above the liquid

level for at least 90% of circumference. 9.3.2 The maximum permissible gap between the primary seal and the shell shall not

be more than 6 mm. Roof of cone roof tanks shall not have depressions that will permit accumulation of water.

10. FABRICATION & ERECTION-GENERAL

10.1 Fabrication and erection of tanks shall be in accordance with API Standard 650. 10.2 Erector shall completely fabricate each tank including all accessories, regardless of

who supplies the accessories. Tank gagging shall be installed and calibrated under the direct supervision of the Vendor of the tank gagging equipment.

10.3 Erector shall supply all labor, equipment, inspection equipment and materials,

supervision and tools, in addition to the requirements in the conditions of contract to erect all storage tanks.

11. WELDING

11.1 General Requirements

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11.1.1 No restraint of bottom plates by weights during welding is permitted.

11.1.2 A minimum of two passes weld shall be deposited on all lap bottom plate

welds using low hydrogen type electrodes. The bottom leg of the finished weld shall be “t” minimum. A minimum of 70% of the unwedded plate tensile strength is required for the weld joint strength. (See subsection 11.6.1 below).

t

2i

t

2.4mm Min. 11.1.3 All shell joints shall be full penetration, double welded joints. 11.1.4 Shell to bottom plate fillet welds shall consist of two passes minimum, both

sides. 11.1.5 Back-up rings or strips, when permitted, shall be of the same chemical

analysis as the base plate. Except for low alloy base plate, the back-up strip shall be low carbon steel.

11.1.6 After the removal of any temporary backup rings of strips, the weld area

shall be dressed and examined using magnetic particle or liquid penetrate.

11.2 Welding Procedure and Welders’ Performance Qualification

11.2.1 Vendor shall submit for approval prior to material supply his weld preparation procedure including details of beveled plates to be supplied. This should also be according to API 650.

11.2.2 Erector shall submit his weld preparation and procedure for approval after

receiving full data as laid out in Section 10 and 11 prior to fabrication. This should also conform to Section7 of API 650.

11.2.3 The fabricator shall specify the application of each welding procedure; for

example, for welding the vertical shell joints, or circumferential joints, nozzles, etc.

11.2.4 All welding procedures submitted shall be identified with the specific item

and purchase order numbers. 11.2.5 The fabricator shall show the applicable welding procedure and non-

destructive testing required on a drawing. NDT (Non-Destructive Testing) and welding procedure number or identification may be shown either on the drawing notes or on the applicable weld joint.

11.2.6 For automatic submerged are processes, the procedure qualification test

shall be conducted on plate of the maximum thickness to be welded in production. Fabrication shall be performed using the same name brand and

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AWS-ASME classification of wire and flux combination, amperage and volage as used for the procedure qualification.

11.3 Filler Metal

11.3.1 The use of carbon 1/2 moly filler metal for welding carbon steel is not

permitted. 11.3.2 Electrodes classified as E6012, E7014, E7020, and E7024 are not

acceptable for making shell or bottom welds. (See paragraphs 11.1.2) E6012 and E7024 electrodes may only be used for making roof welds with

NIOEC’s approval. 11.3.3 Tack welds shall be made with the same type or electrode that is used for

depositing the root pass.

11.4 Weld Joint Preparation

11.4.1 The parts to be jointed by fillet welds shall be brought together as closely as practicable. The gap between faying surfaces of lap joints should not exceed 1.5mm. If the separation is greater than 1.5mm after straightening and assembly, the leg of the fillet weld shall be increased by the amount of separation but shall not exceed 4.5mm gap. The use of filler materials is prohibited.

11.4.2 Peening of butt welds shall not be permitted extent to the extent necessary

to clean the weld. 11.4.3 The Erector shall not proceed to bevel the edge of any plates without first

receiving NIOEC’s approval. 11.5 Weld Heat Treating Requirements

11.5.1 Pre-heating

The applicable codes references the minimum preheat requirements for carbon, low alloy high strength, or heat treated steel materials. (See 5.2.1.2 of API 650)

11.5.2 Post-heating

For carbon steel material over 32mm and materials for special service conditions, the requirements of relevant paragraph, API Standard 650 apply.

11.6 Required Testing

11.6.1 Lap Welded Tank Bottoms

a. 600 linear mm of lap weld shall be fabricated for test specimens. This test joint shall be made using the same fabrication (electrode, plate, and weld procedure) as used to make the production joint.

b. Three tensile test strips 75mm x460mm shall be cut form test weld

according to ASME Sec. IX. The minimum breaking load of the strips

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shall be at least 70% of the minimum ultimate strength of the unwedded plate. A weld shall indicate at least 95% shear fracture.

c. Three cross sections of the test plate well-meant shall be polished and

etched sufficiently to show the weld’s penetration into the base material. Full fusion shall exist throughout each cross section. If the first pass destroys the vertical edge of the lap weld, a minimum of 2.4 mm peak penetration into the bottom plate shall be shown (see sketch, subsection 11.1.3).

11.7 Brinell Hardness Tests

Brinell hardness tests of welds shall be performed on a test plate for semi-automatic gas metal-arc welding and automatic welding processes. The results, with a maximum allowable of 225 BHN, shall be recorded on the applicable welding procedure.

11.8 Charpy “V Notch” Impact Testing

When required by the applicable API Standard, 650, Chirpy V-Nortch impact tests of weld and heat affected zone shall meet the minimum requirements specified for the base material.

12. TESTING AND INSPECTION

12.1 Material on Vendors purchase orders for tanks will be subject to inspection. 12.2 Fabricated material and tank erection will be inspected by the NIOEC inspector. 12.3 Weld seams shall be spot examined by radiography rather than sectioning. 12.4 Non destructive testing shall be in accordance with API 650 and shall conform to

the requirements of the particular design basis of each tank. 12.5 All tanks shall have bottoms, shells and roofs tested in accordance with API

Standard 650. Shell be tested by filling tank with water. Vacuum testing shall be used for all tank bottoms and roofs. Testing shall conform to API 650 requirements in addition to those specified herein.

12.6 All tanks must be cleaned to the satisfaction of NIOEC’s inspector before filling

for testing. Interior of tanks shall be free from grease, weld spatter, scale, slag, rust and any other foreign matter and broom-swept.

12.7 Floating roofs shall be tested by the following methods:

12.7.1 Center deck plates, pontoon bottom plates and rim plate with welded joints shall be sprayed with a penetrating oil such as light gas oil on the bottom side and inspected visually on the top side and inside of rim plates.

12.7.2 Each completed compartment of pontoon roofs shall be individually tested with air pressure of 7.5 * 10-3 bar = 7.5 mbar. A soapy water mixture shall be applied to all welded joints under pressure.

12.7.3 The floatation test:

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The roof shall be given a floatation test while the tank is being filled with water and emptied. During this test the upper side of the lower deck and all pontoon compartments shall be examined for leaks. The appearance of a damp spot on the upper side of the lower deck shall be considered evidence of leakage.

12.7.4 Roof drains together with any flexible couplings incorporated with them

shall be subjected to a hydrostatic test pressure of 3.5 bar (g) while the tank is empty. Drain piping should be flushed through to ensure the absence of any internal obstruction. During the floatation test the roof drain valves shall be kept open and observed for leakage of tank contents into the drain lines.

12.7.5 Hydrostatic testing of tank is mandatory and shall be performed by filling

the tank with water in accordance with API 650. 12.7.6 On satisfactory issue testing, API standard monograms shall be applied on

all tanks. 12.7.7 Tanks shall be strapped according to API 2550. Strapping is the

responsibility of the fabricator but NIOEC shall oversee and approve strapping program and gage tables and fabricator shall submit his proposed program well in advance to NIOEC for approval. Representative of operating company (refinery & distribution) shall witness.

13. DRAWINGS

In addition to the requirements stated in the conditions of contract the following shall also be included: 13.1 Two hard copy of the working and erection drawings shall be submitted for

NIOEC’s approval as soon as possible after the receipt of order. The item number, the weight of materials required and details of welded connections shall be clearly shown on all working drawings. The foundation camber specified in the order shall be clearly stated on the layout drawing of the tank bottom.

13.2 The working drawings shall included those for stairways, gangways and all fittings

and mountings plus one orientation drawing showing the general outlook of the vessel.

13.3 All working drawings shall have received approval prior to the commencement of

fabrication, and before any materials are processed in such manner that the Purchaser is committed by consideration of delivery or for any other reason to approve the design proposed by the Vendor.

13.4 NIOEC reserves the right to require copies of the design calculations.

13.5 Dimensioning on all drawings shall be in the metric system.

14. INFORMATION TO BE SUPPLIED WITH PROPOSAL

In addition to the specified requirements as laid down in the tank Data Sheets the following shall be submitted:

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a. Tank height and diameter (meters and feet) b. Tank capacity (U.S. barrels and cubic.m) c. Calculated and actual thickness of shell, roof and bottom plates. d. Materials of tank shell, roof and bottom, and structural steel. e. The design of the welding joints on tank plates, and welding procedure. f. The type of sealing system proposed on floating roof tanks. g. Slope of tank roof on fixed roof tanks. h. Completed Data Sheet conforming with API 650 blanked format (see Appendix I).

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APPENDIX I

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APPENDIX I (CONT’D)

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DOCUMENT CODE 19 - صفحه اصليdigilib.monenco.com/documents/10157/4214663/SP-41-01.pdf · DOCUMENT CODE NO. OF PAGES: 19 ... A live load of 1200N/m2 ... and inaccessible bottom