015 DH 1003 Rectangular Tanks

KUWAIT OIL COMPANY (K.S.C.)

Engineering Group

Specification Number

015-DH- 1003

Rectangular Tanks

CONTENTS

X Engineering Group Specification

1.0 SCOPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

. . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.0 STANDARD SPECIFICATION 3


01 5-DH-1003

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.0 SERVICE CONDITIONS 4 I

. . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.0 TECHNICAL REQUIREMENTS 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1 Design Parameters 4

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2 Design Loadings 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3 Minimum Thickness 5

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.4 Calculations 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5 Materials 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.6 Supports 6

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.7 Fabrication 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.8 Welding 7

. . . . . . . . . . . . . 4.9 Manholes. Nozzles and Inspection Openings 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.10 lnternals 9

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1 1 External Details 9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.12 Tolerances 10

Rev

1

. . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.0 INSPECTION AND TESTING 10 5.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

. . . . . . . . . . . . . . . . . . . . . . . . . 5.2 Radiographic Examination 10 . . . . . . . . . . . . . . 5.3 Dye Penetrant and Magnetic Examination 11

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4 Testing 11

6 .0 PAINTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Date

23-5-94

. . . . . . . . . . . . . . . 7.0 PACKING. MARKING AND DOCUMENTATION 12

Sheet

2 0 f 12

I . . . . . . . . . . 8.0 SPARE PARTS AND MAINTENANCE REQUIREMENTS 12

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.0 BIBLIOGRAPHY 1 2

1 .O SCOPE

1.1 This specification covers the design, manufacture, inspection, testing and supply of rectangular tanks for installation at the Facility in Kuwait.

1.2 This specification complements the data sheets for the equipment, in which the operating conditions and other requirements are listed in detail.

1.3 The supply of rectangular tanks shall fully comply with all relevant contractual requirements specified in the Scope of Work and Technical Specification of the Contract.

2.0 STANDARD SPECIFICATIONS

2.1 Rectangular tanks shall conform in design, materials, except where otherwise specified, with the current issue and amendments of the following prevailing on the effective data of the Contract:

2.1.1 International Standards

API 650 Welded Steel Tanks for Oil Storage

ASME IX Welding and Brazing Qualifications

ASME 81 6.5 Steel Pipe Flanges and Flange Fittings

2.1.2 Engineering Group Specifications

All equipment and accessories covered by this specification shall comply with all relevant Engineering Group Specifications of which the following are specifically referenced in this specification:

Basic Design Criteria

International Codes and Standards

The Use of Brackish Water for Site Hydrotesting of Equipment

Shop and Field Painting

Welding Procedure Approval of Welding Quality Requirements

Packing, Marking and Documentation

Spare Parts and Maintenance Requirements

Compliance with this specification shall not relieve the Contractor of its responsibility to supply equipment suited to meet the specified service conditions of applicable regulations.

Where conflicts exist between this specification and other specifications, standards, codes or drawings, the most stringent shall be applied.

SERVICE CONDITIONS

Rectangular tanks shall be suitable for continuous operation at a desert location under high ambient temperatures and humidity. The atmosphere at the Facility is generally dusty and corrosive and may contain traces of hydrogen sulphide.

Rectangular tanks shall in all respects be suitable for continuous operation in the service conditions stated in the Engineering Group Specification entitled "Basic Design Criteria" (Number 01 5-AH-1 001 ) .

4.0 TECHNICAL REQUIREMENTS

4.1 Design Parameters

4.1 .I The design pressure shall be as specified on the tank data sheet plus the static head of liquid.

4.1.2 The design temperature shall be as specified on the tank data sheet but shall not be less than 93°C.

4.1.3 Hydrotest shall be as per section 5.4. of this specification.

4.1.4 The allowable design stresses for plate, stiffeners and supports shall not exceed the lesser of the following:

a. 213 of yield strength at design temperature.

b. 138 N/mm2 (20,000 psi).

4.1.5 Corrosion allowance shall be 3 mm minimum, unless specified otherwise on tank data sheet.

4.1.6 Stiffeners shall be located on the outside of the tank.

4 . 2 Design Loadings

The tanks shall be designed for the most severe combination of the following loadings:

Specification Number Rev Date Sheet Engineering Group Specification 01 ~ - D H - I O O ~ 1 23-5-94 5 0 f 12

Dead Loads

Loads resulting from weight of the tank plus all attachments, including platforms and ladders, etc.

Superimposed Loads

Tank roofs and supporting structures shall be designed for a superimposed load of the greater of the following:

a. A load of 2KN/m2 (0.29 psi), excluding weight of roof.

b. A point load of 1 KN (225 Ib) at any point, over a circle of radius 50 mm.

Insulation Loading

a. Insulation weight shall be added to the superimposed weight.

b. For design purposes, the insulation weight shall be taken as 1 50 kg/m3.

Contents

For the shell and base design, the specific gravity of the contents shall be taken as not less than 1.0.

Shipping Loads (Sea Transportation)

The design of tanks to withstand "ship out" loadings as specified in the Engineering Group Specification entitled "Packing, Marking and Documentation" (Number 01 5-UH-1001).

4.3 Minimum Thickness

Plate thicknesses shall be established dependent on the location of stiffening members and shall satisfy the following:

4.3.1 The maximum deflection of stiffeners (in the corroded condition) shall not exceed 11300 of span under all combinations of loading.

4.3.2 The maximum deflection of plate panels (in the corroded condition) shall not exceed half the plate thickness under all combinations of loading.

4.3.3 The maximum allowable design stress shall not be exceeded.

4.3.4 The hydrostatic test pressure shall not stress any part of the tank in excess of 90% of the yield stress in the corroded condition.

4.3.5 The thickness of any plating shall not be less than 6 mm plus corrosion allowance or the thickness specified on the related data sheets whichever is greater.

4.3.6 The flat plate design shall be in accordance with Roark's Formulas for Stress and Strain, by Warren C. Young (see section 9.0).

4.3.7 Internals, whether fixed or removable, shall not be less than the greater of the following:

a. 3 mm + (corrosion allowance x 2) for fixed internals.

b. 3 mm + corrosion allowance for removable internals.

c. 6 mm including corrosion allowance.

4.4 Calculations

Comprehensive design calculations shall include the following:

4.4.1 Derivation of plate thickness and stiffening member sizes required to satisfy the internallexternal design pressure conditions plus any other loadings required by this specification or tank data sheets.

4.4.2 Evaluation of stresses and deflections due to test conditions.

4.4.3 Evaluation of stresses at supports, lifting facilities and other attachments.

4.4.5 Evaluation of stresses for local loads due to piping, live loads, etc.

4.4.6 Derivation of weights and centre of gravity positions for sea shipment.

4.5 Materials

4.5.1 Materials used for tank fabrication shall be in accordance with the tank data sheet. The materials shall satisfy the requirements of the codes and standards specified in the tank data sheets.

4.5.2 The Carbon Equivalent (CE) shall be calculated from the Ladle analysis using the formula:

The CE shall not exceed 0.43%.

4.5.3 The maximum carbon content shall be 0.23%.

4.8.1 All welders shall be qualified in accordance with Section IX of the ASME Boiler and Pressure Vessel Code.

Engineering Group Specification

4.8.2 Welding procedures and qualifications shall be in accordance with

4.5.4 All plates used for the tank shall have heat-number stamps on them for correlation with inspection and mill certificates. Stamping shall be on outside wall of tanks.

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01 5-DH-1003

4.6 Supports

4.6.1 Tank bottoms shall be designed to be supported on two lateral beams. The beams shall be continuously welded to the tank bottom, and the positions of the beam shall be specified by the Company-Approved tank Manufacturer.

Rev

1

4.6.2 Tanks shall be self-supporting without the aid of bracing for all design conditions.

4.7 Fabrication

Date

23-5-94

4.7.1 The bottom edge of the bottom side plates shall be cut square for welding directly to the tank bottom.

Sheet

7 of 12

4.7.2 All vertical and horizontal joints in plates shall be double butt- welded joints with full penetration and fusion.

4.7.3 All seam welds shall be so located as to clear all tank appurtenances and their reinforcing pads by a minimum of 50 mm.

4.7.4 All vertical seams shall be offset by at least 10 times the thickness of the plate.

4.7.5 All corner joints shall be continuous fillet welds on both sides.

4.7.6 Nozzles shall be set through and shall be welded from both sides with full penetration welds.

4.7.7 Plate material shall be straightened and/or flattened by pressing or rolling, and this shall be done before the material is processed in any way.

4.7.8 Tack welds for side to bottom fillet welds, if used, shall be removed.

4.7.9 The flat roof shall not have depressions that will permit accumulation of water.

4.8 Welding

Section IX of the ASME Boiler and Pressure Vessel Code and the Engineering Group Specification entitled "Welding Procedure Approval and Welding Quality Requirements" (Number 01 5-WH- 1001).


4.9 Manholes, Nozzles and Inspection Openinns

Manholes shall comply with API 650, Fig. 3-1 2, and shall be 600 mm inside diameter whenever possible.


01 5-DH-1003

Handholes (two) minimum size 8 in. nominal bore (NB) shall be provided when the size of tank prohibits the provision of a manhole.

Wear plates or impingement baffles shall be installed at inlet nozzles where erosion will take place. The design of such devices shall be based on an operational life of 20 years.

Rev

1

Covers, complete with bolting and gaskets, shall be fitted to all manholes, handholes, inspection openings and cleanout openings. Covers weighing in excess of 3 4 kg shall be furnished with davits or hinges and handles. Davits shall comply with API 650. Covers and davit shall be painted in accordance with the Engineering Group Specification entitled "Shop and Field Painting" (Number 0 1 5-XH- 1 005).

All tank openings shall be flanged and not less than 2 in. NB. In the case of certain tanks within "packages," screwed connections may be considered. Any such deviation must be approved by the Company before placement of purchase order.

Date

23-5-94

Forged screwed couplings shall be ANSI 3000 Lb series with NPT thread.

Sheet

8 of 12

Nozzles sizes 1 1 14 in., 2 1 12 in., 3 1 12 in., 5 in. and 7 in. shall not be used.

Nozzles used as drains or located such that interference with tank internals would occur shall be flush with the inside face of tank.

Nozzles used for instrumentation such as level controls and gauge glasses shall be jig set to prevent tolerances being cumulative.

4.9.10 Nozzles 4 in. NB and above, with the exception of manholes and access openings, shall be reinforced using the 100% area replacement method. Reinforcement shall be similar material to the tank plate to which they are attached.

4.9.1 1 Tell-tale holes 114 in. NPT shall be provided complete with

threaded plug-in reinforcement plates (plug to have hexagonal head). One hole is required for nozzles up to and including 10 in. NB, larger nozzles shall have two holes 180" apart. Reinforcement plates made from segments shall have one hole in each segment. On insulated tanks, each tell-tale hole shall be fitted with a screwed-in pipe projecting 25 mm beyond the insulation surface. Thread protectors shall be fitted to all tell-tale holes prior to shipment.


4.9.12 Flanged nozzles shall have a projection from inside of the tank wall to the face of flange (measured at shortest point) as follows:

a. Up to 3 in. NB, 180 mm.


o I 5-DH-1003

b. 4 in. NB to 10 in. NB, 200 mm.

c. Above 10 in. NB, 250 mm.

Rev

I

4.9.13 When insulation is 100 mm thick or greater, flanged nozzle projections shall be increased by:

a. 25 mm for 100-mm-thick insulation.

Date

23-5-94

b. 50 mm for 125-mm-thick insulation.

Sheet

9 of 12

c. 75 mm for 150-mm-thick insulation.

4.9.14 The minimum nozzle neck thicknesses shall be standard wall plus the corrosion allowance specified on the tank data sheet.

4.9.15 Pipe nozzle necks shall be ASTM A 106-Gr.B or API 5L-Gr. B material. Plate nozzle necks may be used for nozzles 16 in. NB and above, and plate material shall be same as tank plate.

4.9.16 Nozzle flanges shall be 150 Ib, raised face, slip-on or weld-neck type in accordance with ASME B16.5 unless otherwise noted on the tank data sheet. Manway covers and manway flanges shall be made from plate with dimensions in accordance with API 650.

4.10 lnternals

4.10.1 Piping, vortex breakers, ladder rungs and all other internals specified on the tank data sheets shall be supplied by the Approved Manufacturer.

4.10.2 The minimum leg length of internal fillet welds attaching fixed internals shall be 5 mm plus the corrosion allowance specified on the tank data sheet. All welds shall be continuous.

4.10.3 Removable internal piping shall be flanged. Internal flanges of forged type with a minimum of four bolts shall be used.

4.10.4 Removable internals shall be sized to enable removal through the tank manway.

4.1 0.5 All internal bolting shall be type 31 6 stainless steel.

4.1 1 External Details

4.1 1 .I Insulation supports (if required), stiffeners, lifting lugs, ladder, platform and pipe support clips, etc. specified on the tank data sheet shall be supplied and fitted by the Approved Manufacturer.

4.1 1.2 All external fittings shall be attached to tank using continuous fillet welds.

4.1 1.3 Where external attachments may cause excessive stress concentration, doubling plates shall be attached to tank wall. Pads shall have a % in. NPT vent hole complete with plug. Corners of rectangular plates shall be radiused 25 mm minimum.

4.12 Tolerances

4.1 2.1 Tank length, width and height shall be within + 5 mm per 3000 mm. Limit tolerance shall be a minimum of + 3 mm and a maximum of + 13 mm. The flatness of plates shall be 11300 of span against the direction of deflection under load and 11600 in the same direction as load.

4.1 2.2 The butting edges of plates shall at no point be out of alignment by more than 20% of the relevant plate thickness.

4.12.3 Nozzle positions measured from the edge of the tank shall be within ~t 3 mm. Flange faces shall be true to the vertical within ~t 0.5 degree.

4.1 2.4 The tolerance on the distance between any pair of instrument connections shall be ~t 2 mm.

4.1 2.5 The tolerance on the standout of any nozzle shall be * 5 mm (i.e., from inside tank wall to face of the flange).

5.0 INSPECTION AND TESTING

5.1 General

5.1 .I All tanks shall be liable to inspection by the Company.


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01 5-DH-1003

Rev

I

Date

23-5-94

Sheet

1 0 of 12

5.1.2 All acceptancelrejection criteria shall be as detailed within this specification and API 650 for welding quality1NDT requirements.

5.2 Radioclraphic Examination

Radiographic examination shall be performed when specified on the tank data sheet or when requested by the Company for determination of defect extent.

All butt welds shall be spot radiographically examined. The number, definition and standards of acceptability shall be as specified in API 650. Percentage radiography shall be based on the weld footage in each individual tank.

Where spot radiographic examination is specified, all junctions of welds and all repaired areas shall be fully radiographed as a minimum requirement.

Where 100% radiography is required, this shall include nozzle attachment butt welds where feasible, flange to nozzle neck butt- welds; and longitudinal seams of rolled plate nozzle necks.

5.3 Dve Penetrant and Magnetic Examination

5.3.1 All tank corner joints shall be subjected to dye penetrant testing inside and outside.

5.3.2 The reverse side of double-sided butt welds shall be backchipped or ground to sound metal before welding and the weld checked by magnetic particle detection.

5.3.3 Welds attaching nozzles, manholes and all other openings shall be inspected by wet magnetic particle detection or dye penetrant inspection.

5.4 Testinq

5.4.1 Tanks shall be tested hydrostatically or as otherwise specified on the related tank data sheet. In no case shall the test pressure be less than that obtained by filling to the top of a standpipe projecting 2 m above the top of the tank.

5.4.2 The hydrostatic test shall be maintained for a minimum period of four hours. The Approved Manufacturer shall monitor deflections of all plates and stiffeners during and after hydrotest, when so requested by the Company.

5.4.3 Nozzle reinforcement plates shall be subjected to a I .O-barg airlsoapy water test via the tell-tale holes.

5.4.4 Service bolting and gaskets furnished by the Company's Approved Manufacturer shall not be used in testing.

5.4.5 After hydrostatic testing of the tank, it shall be dried and cleaned internally, and all nozzles shall be blanked off using temporary steel blanks.

5.4.6 For any Site hydrotesting, brackish water with chemical inhibitors shall be used in accordance with the Engineering Group Specification entitled "The Use of Brackish Water for Site Hydrotesting of Equipment" (Number 01 5-CG-1001). Tanks shall be flushed with fresh water after hydrotest.

5.4.7 The shop test water for stainless steel tanks shall be demineralised with a maximum chloride content of 30 ppm.

6.0 PAINTING

Painting of the tank shall be in accordance with the tank data sheets and the Engineering Group Specification entitled "Shop and Field Painting" (Number 01 5- XH-1005).

7 .O PACKING, MARKING AND DOCUMENTATION

For all relevant requirements, refer to the Engineering Group Specification entitled "Packing, Marking and Documentation" (Number 01 5-VH-1001).

8.0 SPARE PARTS AND MAINTENANCE REQUIREMENTS

For all relevant requirements, refer to the Engineering Group Specification entitled "Spare Parts and Maintenance Requirements" (Number 01 5-KH-1902).

9.0 BIBLIOGRAPHY

1. Roark's Formulas for Stress and Strain (latest edition), by Warren C. Young.

2. TheoryofPlatesandShells, by S. Timeshenko and S. Woinowsky - Krieger.


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0 1 5-DH-1003

Rev

1

Date

23-5-94

Sheet

12 of 12

015 DH 1003 Rectangular Tanks

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