D-01 NOC

NATIONAL OIL CORPORATION

GENERAL ENGINEERING SPECIFICATION

GES D.01

ATMOSPHERIC STORAGE TANKS (API 650)

Rev Date Description Checked Approved

0 1999 Issued for Implementation DL

Compiled by Teknica (UK) Ltd

GENERAL ENGINEERING SPECIFICATION ATMOSPHERIC STORAGE TANKS (API 650)

GES D.01 Page 2 of 25 Rev 0 1999

INDEX SECTION TITLE PAGE 1.0 SCOPE OF SPECIFICATION 4 1.1 Introduction 4 1.2 Other NOC Specifications 4 2.0 DEFINITIONS 5 2.1 Technical 5 2.2 Contractual 5 3.0 DESIGN 6 3.1 Codes and Standards 6 3.2 Additions and Exceptions 7 4.0 MATERIALS 15 4.1 Materials of Construction 15 4.2 Chemical Composition 15 5.0 FABRICATION AND ERECTION 16 5.1 Introduction 16 5.2 Procedures 16 6.0 TOLERANCES 18 6.1 Fabrication 18 6.2 Curvature 18 6.3 Roundness 18 7.0 INSPECTION 19 7.1 Procedures 19 7.2 Methods 19 8.0 TESTING 21 8.1 Statutory Testing 21 8.2 Test Procedures 21 8.3 Nameplates 22



SECTION TITLE PAGE 9.0 DOCUMENTATION 22 9.1 Introduction 22 9.2 Schedules/Reports 22 9.3 Data and Calculations 23 9.4 Drawings 23 9.5 Other Documents 24 9.6 Manuals 24 10.0 PRIOR TO SHIPMENT 24 10.1 Painting and Coatings 24 10.2 Spares 25 10.3 Packing/Storage 25 10.4 Shipping 25 10.5 Warranties 25 DATA SHEETS Tank (4)



1.0 SCOPE OF SPECIFICATION 1.1 Introduction 1.1.1 This specification covers the minimum requirements for mechanical design, materials,

fabrication, erection, inspection and testing of welded steel storage tanks for above ground atmospheric storage with a capacity in excess of 10,000 bbl (1600m3).

1.1.2 These storage tanks shall be designed, fabricated, erected, inspected and tested in accordance

with API 650, plus the additional requirements of this specification. 1.1.3 Low pressure storage tanks suitable for vapour space pressures of up to 15 psig (100 kPag) are

covered by GES D.04. Tanks of 10,000 bbl(1600m3) capacity or smaller are covered by GES D.06. Accessories for tanks are covered by GES D.02.

1.1.4 This specification applies to equipment for refineries, onshore oil and gas installations and

processing facilities. 1.1.5 The Purchase Order/Contract will state that the tanks will be purchased either by: (a) Owner buying tank materials and a local Vendor/Contractor carrying out the erection, or (b) local Contractor carrying out procurement and erection. 1.1.6 The Vendor/Contractor shall comply fully with the provisions laid down in this specification.

Any exception must be authorised in writing by the Owner. 1.1.7 In the event of any conflict between this specification and any applicable codes or standards, the

Vendor/Contractor shall inform the Owner in writing and receive written clarification from the Owner before proceeding with the work.

1.1.8 The tank foundations will be provided by the Vendor/Contractor responsible for the erection of

the tanks. 1.1.9 This General Engineering Specification will form part of the Purchase Order/Contract. 1.2 Other NOC Specifications 1.2.1 Where indicated in this specification the following additional Specifications shall apply: GES D.02 - Accessories for Atmospheric Storage Tanks GES D.06 - Small Storage Tanks GES D.07 - Sump Tanks GES H.07 - Fire-fighting Facilities on Storage Tanks GES W.01 - Welding Procedures and Welder Qualifications GES W.03 - Post-weld Heat Treatment of Materials GES X.01 - Surface Preparation and Painting Application GES X.02 - Colour Coding of Equipment and Piping Systems GES X.03 - External Protective Coatings



2.0 DEFINITIONS 2.1 Technical The technical terms used in this specification are defined as follows: Low Strength Tank Steel Steels having a specified minimum yield strength equal to or less than 43,000 psi (296 MPa) and a

specified maximum tensile equal to or less than 85,000 psi (586 MPa). High Strength Tank Steels Steel having a specified minimum yield strength greater than 43,000 psi (296 MPa) and a

specified maximum tensile strength equal to or less than 100,000 psi (689 MPa). Peaking Peaking is the deviation of shell contour from a true circle at vertical joints. Peaking shall be

determined over a horizontal span of 36″ (915 mm) centred on the weld. Banding Banding is the deviation of the shell at horizontal joints from a vertical line. Banding shall be

determined over a vertical span of 36 in (915 mm) centred on the weld. Annular Plates Annular plates are bottom plates forming the annular ring upon which the shell rests. Production Impact Test Plate Coupon plate which provides the required impact test specimens for the weld metal and heat

affected zones in the finish product. Plate as Rolled Refers to the unit plate from a slab, or rolled directly from an ingot. 2.2 Contractual The commercial terms used in this specification are defined as follows: 2.2.1 Owner The oil or gas company, an associate or subsidiary, who is the end user of the equipment and

facilities. 2.2.2 Vendor The company supplying the equipment and material. 2.2.3 Contractor The main Contractor for a defined piece of work



2.2.4 Sub-Contractor A company awarded a contract by a Contractor to do part of the work awarded to the Contractor. 2.2.5 Inspection Authority The organisation representing the Owner or Vendor/Contractor that verifies that the equipment

and facilities have been designed, constructed, inspected and tested in accordance with the requirements of this specification and the Purchase Order/Contract.

2.2.6 Inspector A qualified individual representing the Owner, Vendor/Contractor or the assigned Inspection

Authority, who verifies that the equipment and facilities have been designed, constructed, inspected and tested in accordance with the requirements of this specification and the Purchase Order/Contract.

3.0 DESIGN 3.1 Codes and Standards 3.1.1 The design and construction of storage tanks shall comply with this specification as well as with

codes, standards and provisions indicated on the data sheets provided by the Owner. 3.1.2 This specification is based on the standards listed below: API - American Petroleum Institute API 650 - Welded Steel Tanks for Oil Storage API 2000 - Venting Atmospheric and Low-Pressure Storage Tanks - Non-

refrigerated and refrigerated API 2517 - Evaporation Loss from External Floating Roof Tanks ASME - American Society of Mechanical Engineers Section II - Material Specification Part A Ferrous and Part B Non-ferrous Section IIC - Specification for Welding Rods, Electrodes and Filler Metals Section IID - Material Properties Section V - Non-destructive Testing Section VIII - Pressure Vessels, Division 1 Section IX - Welding and Brazing Qualifications ASTM - American Society Testing & Materials ASTM E 162 - Test Method for Surface Flammability of Materials using a

Radiant Heat Energy Source



ANSI - American National Standards Institute ANSI A12.1 - Safety Requirements for Floor and Wall Openings, Railings and

Toe Boards ANSI A14.3 - Safety Requirements for Fixed Ladders ASME - American Society of Mechanical Engineers ASME B16.5 - Pipe Flanges and Flanged Fittings ASME B16.9 - Factory Made Wrought Steel Butt-welding Fittings ASME B16.11 - Forged Steel Fittings, Socket-Welding and Threaded ASME B16.47 - Large Diameter Carbon Steel Flanges ASME B31.3 - Process Piping 3.1.3 Unless specified otherwise in the Purchase Order/Contract, the current editions of Codes and

Standards at the time of order should be used. 3.2 Additions and Exceptions In addition to the minimum requirements of the API 650 design code, the following shall be

taken into consideration: 3.2.1 Corrosion Allowance (a) Minimum corrosion allowance for tank components constructed from carbon steel shall

be 1/16" (1.5 mm) in sweet service and _" (3 mm) in sour and corrosive service. (b) The design diameter of anchor bolts and the design thickness of holding down straps,

shall be increased in all cases by _" (3 mm) as corrosion allowance. 3.2.2 Design Loads (a) Design loading of the tank shall take into account cyclic operations, erection and test

loadings. (b) During erection, start-up or operation, all applicable loads shall be considered as acting

simultaneously. (c) During hydrostatic testing, wind load (wind pressure) equivalent to a 35 mph (16 m/s)

wind velocity shall be considered acting simultaneously with the hydrostatic test load. (d) Roof live load shall not be less than 25 lbs/ft² (1.2 kN/m2) applied over the projected roof

area. 3.2.3 Bottom (a) Bottom plates shall be two pass welded with 70% joint efficiency. (b) Minimum shell to bottom fillet size shall be the same as the bottom annular plate

thickness. (c) Annular plate thickness shall be the greater of API 650 Table 3-1 or the Table below:



BOTTOM SHELL COURSE THICKNESS

ANNULAR RING PLATE MINIMUM THICKNESS

Less than or equal to ½" (12.5 mm) ¼" (6 mm)

Over ½" to _" in (12.5 to 22 mm) 5/16" (8 mm)

Over _" to 1¼" (22 to 32 mm) _" (9.5 mm)

Over 1¼" (32 mm) 7/16" (11 mm) 3.2.4 Shell The shell course thickness shall be designed per the one foot method of API 650 with the

following modifications: - specific gravity, G. Use 1.0 if actual G is 1.0 or less and use actual value if G is greater

than 1.0; - minimum nominal thickness of shell shall not be less than ¼" (6 mm). Subject to approval by the Owner, shell thickness determination by variable design point method

may also be acceptable for large diameter tanks. All vertical and horizontal shell joints shall be complete penetration and complete fusion welds.

Single pass butt welds are not permitted. 3.2.5 Wind Girders (a) Wind girders for open top and floating roof tanks shall meet the strength as specified per

API 650. (b) Wind girders are to be used as walkways and shall be a minimum of 30" (762 mm) wide

and shall be located 42" (1.07 mm) below the top of the tank. Hand railings shall be provided, only if the tank is equipped with fire fighting foam facilities.

(c) Top curb angle - where a curb angle is required at the top of the shell of floating roof

tanks, the horizontal leg shall extend outwards. (d) Wind girders shall slope outward and shall be provided with drain holes. 3.2.6 Fixed Roof Design (a) Roof supports - 1/32" (0.8 mm) corrosion allowance to be provided on all surfaces, i.e.

1/16" (1.6 mm) total of rafters, girders and columns. (b) Live load for roof supports design shall be per the National Building Code, but not less

than 25 lbs/ft2 (1.2 kN/m2) of projected areas. (c) For "hot tanks" or tanks subject to earthquakes, rafters shall be able to slide, but shall be

restrained. (d) Roof support columns shall be made from pipe only. Structural sections are

unacceptable. Columns shall be drained and vented. Drains shall not allow liquid to be trapped in the column when tank is emptied. A ¾" (19 mm) diameter hole shall be provided on each column 12" (305 mm) above the floor for flushing purposes.



(e) The Owner shall specify to the Vendor/Contractor any lateral loads which may be imposed on the roof supporting columns, e.g. tank mixers.

(f) Circumferential roof angle - the horizontal leg of the roof supporting angle shall be

turned inward or outward, as specified by the Owner. (g) Overhangs shall not be allowed. (h) A frangible joint at the roof-to-shell junction shall be provided for supported cone and

self-supporting cone roof designs. (i) When a self-supporting dome or umbrella roof design is specified, emergency venting

per API 2000 shall be provided. (j) Bearing plates shall be provided for roof support columns. Plates shall be 24" (600 mm)

round or square by _" (10 mm) thick. (k) Roof is to slope to ensure self-draining. However, minimum slope is desirable for

personnel safety, therefore, the Vendor/Contractor shall submit a proposal when quoting. Minimum roof plate thickness shall be 3/16" in (5 mm).

3.2.8 Internal Floating Roof Design (a) Flexible seal material shall have a flame spread index of not more than 35 per ASTM

E162. (b) Pan type covered floating roof designs shall not be used. (c) The design of internal floating roofs for use in fixed roof tanks greater than 150 ft (46 m)

diameter and having roof support columns, shall be submitted to the Owner for review. (d) Covered floating roofs shall be designed in accordance with GES D.07. 3.2.9 Floating Roofs (a) Floating roof tanks with specified flush type nozzles shall have the floating roof designed

to permit the outer pontoon to reach a point within 15" (381 mm) of the tank bottom. (b) The Owner shall supply the Vendor/Contractor with details regarding tank mixers,

internal piping, etc. The Vendor/Contractor shall ensure that all appurtenances are clear of the roof in its lowest position.

3.2.10 Floating Roofs Greater than 60 ft (18.3 m) Diameter Single deck, annular pontoon type roofs shall be per the following: (a) All roofs shall be of the low deck (minimum vapour space) type. (b) Centre decks greater than 150 ft (46 m) diameter shall have channel stiffeners on the

underside of the deck. Stiffeners shall be installed as concentric rings with a maximum radial spacing of

20 ft (6 m).


GES D.01 Page 10 of 25 Rev 0 1999

(c) Roofs for tanks greater than 200 ft (61 m) diameter shall be designed for elastic stability

against "gross out-of-plane" buckling and "local" buckling of the outer pontoon, due to the radial load imposed by deflection of the centre deck. This radial load shall be determined from the 10" (250 mm) rainfall loading condition as defined in API 650 Appendix "C" or punctured centre deck loading condition, whichever governs.

(d) Floating roofs shall be of the multiple and liquid tight compartment design. (e) All internal bulkhead plates shall be single fillet welded along all edges for liquid

tightness. (f) Outer pontoon inspection manholes shall be provided with sealed cover. (g) For tanks over 200 ft (61 m) diameter, calculations and tests required to substantiate the

elastic stability of the roof pontoon design, shall be as follows: - where roof designs have not been previously approved by the Owner, the

Vendor/Contractor shall submit test data on a roof of similar diameter to validate the design;

- where validation has not been made, the Vendor/Contractor shall conduct a

proof test on the largest tank supplied on the order. Proof test shall be based on the most critical design loading conditions.

Calculations shall be submitted to the Owner for approval. Roofs greater than 300 ft (91.5 m) diameter shall have the following construction: - roof shall be of the double-deck type; - the top edge of inner rim plates in the first two central compartments shall be

welded with continuous single fillet welds; - all circumferential compartments other than outer compartment shall be

provided with a minimum of four radial partition plates. 3.2.11 Seals (a) Shunts for removing charges, due to lightning, shall be provided on open type floating

roof tanks to connect the weather shield to the roof. Shunts shall be made of stainless steel and shall be spaced not more than 30 ft (9 m) apart.

(b) The peripheral roof seal may, unless otherwise specified, be of the metallic shoe type or

the liquid filled tube type. The seal design and materials of construction shall be approved by the Owner. Liquid filled seals shall be sectionalised, i.e. discontinuous, to prevent the complete loss of the sealing in the event of leakage.

(c) Toroidal type seals shall be equipped with a weather shield, or the tank shall be

equipped with a secondary seal. Decision between weather shield and secondary seal shall be on an economic basis based on calculations using API 2517 (1980 version) and shall be approved by the Owner.

(d) The bottom of the roof seal shall contact the shell just below the liquid level for at least

95% of the circumference. The liquid seal shall be unbroken around the circumference. The maximum precipitation load on the roof shall be taken into account to ensure the seal is not completely submerged.

(e) The maximum permissible gap between the primary seal and the tank shell is _" (3mm)


GES D.01 Page 11 of 25 Rev 0 1999

throughout the working range of the tank. (f) The primary and secondary seal (or weather shield) shall be installed to allow for

removal from the top of the floating roof (when the tank is empty and the roof is resting on its legs).

(g) The primary and secondary seals shall be protected against a "roll over". 3.2.12 Supporting Legs for Floating Roofs (a) Supports shall be carbon steel pipe, Schedule 80 minimum thickness, or stainless steel if

the roof is aluminium. (b) The number of support legs shall be determined on the basis that Schedule 40 pipe would

be used. (c) Supports shall be adjustable to two positions: - the low position shall be the lowest permitted by tank internals; - the high position shall be such that a minimum of 6 ft (2 m) clearance is provided

underneath the cover. (d) For steel roof, bearing plates shall be centred under each support, attached to the tank

bottom by a 3/16" (5 mm) continuous fillet weld. Plates shall be 24" (610 mm) round or square by _" (10 mm) thick.

(e) The length of the leg support sleeves shall be such that any opening will be above the

liquid level when the deck is deflected by the 10" (254 mm) rainfall or punctured centre deck condition. In no case shall the height (ft) of the support sleeve for single deck pontoon roofs be less than the tank diameter (ft) divided by 60.

3.2.13 Roof Drains (a) Emergency drains shall not be provided when the pontoon area is less than 50% of the

roof area. Only for double deck type roofs may credit be taken in the roof design when emergency drains are furnished.

(b) Articulated pipe drains shall be provided with Chicksan swivel joints or equal with Viton

seals. 3.2.14 Ladder Runways (Rolling Type) The designer shall specify the height of the runway to accommodate sand build-up. 3.2.15 Vents for Floating Roof Tanks The Owner shall specify on the inquiry maximum filling and suction rates for the tank service to

facilitate proper sizing of vents. 3.2.16 Tank Connections and Appurtenances (a) All shell opening connections including nozzles, manholes and clean-out fittings shall

meet the requirements of API 650, except that all connections shall be attached by welds fully penetrating the shell.


GES D.01 Page 12 of 25 Rev 0 1999

(b) Local stresses at tank appurtenances, such as agitators, shall be evaluated and sufficient

reinforcing provided to avoid high local stresses. (c) Flanged connections shall be Class 150 rating weld neck type flanges and seamless pipe. (d) Manholes shall be constructed as laid down in the relevant section of the code. Shell

manways shall be in accordance with Figure 3.4A of API 650. Roof manways shall be in accordance with Figure 3.13 of API 650.

(e) The minimum thickness for nozzle necks shall be in accordance with the code, but where

a corrosion allowance is specified, this should be added to the minimum nominal wall thickness.

(f) Reinforcement for all openings must be checked by the Vendor/Contractor against the

code requirements. The minimum outside diameter of the reinforcing ring shall not be less than twice the nominal bore of the nozzle.

(g) Nozzle reinforcing rings shall be fitted with tapped tell-tale holes. Rings in more than

one piece require one tell-tale hole per piece. Tell-tale holes for reinforcing rings to insulated tanks shall be threaded and fitted with piping inserts to project proud of the insulation.

(h) Nozzles NPS 2 and larger shall be flanged. All couplings shall be 3,000 psi rating. (i) Nozzles shall be designed for static liquid and piping loads. (j) Fill and discharge nozzle shall be the API low type unless otherwise specified. (k) For apex down cone bottom tanks, the draw-off line shall be piped to the centre of the

tank, turned down and terminated 4" (100 mm) from the bottom by a flanged connector. The pipe shall be adequately supported to maintain this clearance.

(l) All shell and roof nozzle projections shall be increased to allow for insulation when

specified. (m) Nozzles and manholes which require stress relieving shall be so positioned that the

necks, flanges and reinforcement can be transported to site attached to pre-fabricated plates. Reinforcement of such openings shall be tested and inspected at the Vendor/Contractor's works.

(n) Bolt holes in flanges of shell nozzles and manholes are to straddle the axial centre line.

Bolt holes in flanges of roof nozzles are to straddle NS/EW centrelines, except where otherwise stated.

(o) Drain connections shall be supplied complete with draw-off sump in accordance with

API 650. (p) All roof nozzles shall be located close to access stairways and railings. Landing platforms

to cover all required access points shall be provided either side of the stairway. 3.2.17 Gaskets and Bolting (a) Gaskets and bolting in joints which form an integral part of the equipment, e.g.

manholes, sight glass pads, etc. and terminal joints shall be supplied by the Vendor/Contractor.


GES D.01 Page 13 of 25 Rev 0 1999

3.2.18 Internal Piping (a) Heating coils are to be fabricated from fully welded seamless pipe. Flanged connections

shall not be used. (b) Stilling wells and standpipes may be fabricated from electric resistance welded pipe, but

seamless is preferred. 3.2.19 Stairways, Ladders, Platforms and Walkways Stairways and ladders are to conform to the Vendor/Contractor's standard drawings if specified,

otherwise to be in accordance with the following: (a) Stairways Tanks requiring gauging or sampling from the roof shall be provided with a spiral or

radial stairway and platform, for access to gauge or sampling hatch. A spiral or radial stairway shall be provided for access to floating roof tanks. In addition,

a top platform with a guard railing shall be provided from the top of this stairway to the gauge well and the roof ladder.

Stairway design and construction shall be per API 650, and the following: - minimum effective width of stair shall be 30" (750 mm), except where connecting

to a 24" (600 mm) wide walkway, in which case the effective width shall be 24" (600 mm),

- stair landings shall not be less than 30" (750 mm) in the direction of the stairway. Staircase shall be 6" (150 mm) maximum from tank wall. Angle of rise 45°. Rises of more

than 15 ft (4.5 m) shall be provided with a rest platform. (b) Ladders Tanks not equipped with spiral or radial stairways shall be provided with an external

vertical ladder. Ladders and safety cages shall be per ANSI A14.3, except as modified below: - where ladders are the only means of access, they shall provide for side-step

access to platforms unless through ladder type is specified, - where ladders serve as a secondary access to platforms, they may be either the

side-step or through ladder type installation, - chains with safety hooks or safety gates, shall be provided across ladder

openings at each platform landing, - ladder safety devices shall not be used in lieu of cage protection, - ladders shall be designed for a moving concentrated load of 500 lb (227 kg). (c) Walkways for Interconnecting Tanks The platforms at the tops of ladders or stairways may be interconnected with walkways,

arranged so that personnel are not required to walk across the roof of any tank. (d) Platforms, Guard Railings, Toe Plates Platform floor plates shall have a raised pattern and ¼" (6 mm) nominal thickness.

Drainage shall be provided by one hole, ½" (13 mm) diameter, for approximately every 15 sq ft (1.5 m2) of steel floor plate. Holes shall be located at low spots and shall be drilled after erection.


GES D.01 Page 14 of 25 Rev 0 1999

Guard railings and toe plates shall be per ANSI A12.1. Guard railings shall be constructed of structural steel shapes or pipe. Any pipe railings shall be seal welded to prevent internal corrosion.

For fixed roof tanks, guard railings shall be installed along the edge of the roof, extending

at least 6 ft (1.8 m) beyond the platform in each direction. (e) Additional Requirements for Floating Roof Tanks If the tank diameter is equal to or greater than the height, a rolling type roof ladder shall

be furnished having a minimum angle of 30° from the vertical. If the tank diameter is less than the tank height, it shall have a vertical roof ladder.

For floating roof tanks, guard railings shall not be furnished for windgirders specified to

be used as walkways, except for tanks having an air foam system with multiple outlet foam stations, or if local procedures dictate fire-fighting from the windgirder.

3.2.20 Earthing (a) Each tank shall be fitted with two earthing bosses to the code. Bosses to be positioned as

shown on the tank drawing or data sheet. 3.2.21 Supply and Services If called for on individual tank drawings or tank data sheets, the Vendor/Contractor shall supply: - flame arrestors, - gauge hatch covers (non-sparking, gas or pressure tight to suit design condition), - emergency vent and manhole covers, - liquid level gauges, - vacuum/relief valve, - temperature measuring device. 3.2.22 Fire Prevention System (a) For fire-fighting requirements refer to GES H.07. (b) The tank Vendor/Contractor shall furnish and install firewater deluge system and

components, terminating at laterals at the base of the tank. 3.2.23 Vents for Fixed Roof Tanks (a) Open Type Vents Open vents are required to be sandstorm-proof. Vent sizing shall be per API 2000. The maximum pumping rate and the need for

additional venting capacity of tanks handling spiked crudes, those tanks fitted with heaters, and blending tanks (blending with materials greater than 15 RVP (103.4 kPa)) will be specified.

(b) Pressure Vacuum Vents Pressure vacuum vents shall be used when the following conditions apply:


GES D.01 Page 15 of 25 Rev 0 1999

The stock stored has a flash point below 100°F (38°C). Temperature of stored product is above or within 15°F (8°C) of its flash point at the

highest operating temperature. The stocks stored are valuable and have a low vapour pressure, e.g. methanol. Tank filling and emptying rates for sizing pressure vacuum roof vents shall be specified

on the Tank Data Sheet. For asphalt service, the following limitations shall apply: - goose-neck vents, screens shall not be used; - pressure vacuum vents shall not be used except when the tank is blanketed with

an inert gas system. 4.0 MATERIALS 4.1 Materials of Construction Materials to be used shall be in accordance with API 650 and the additional requirements of this

specification. 4.1.1 A complete material specification shall be submitted with the Vendor/Contractor's bid proposal. 4.1.2 Annular plates shall be of the same material specification and grade as the lowest shell course. 4.1.3 Pipe and formed plate used for nozzles, manhole necks and flush-type clean-out fitting

assemblies shall comply with the following table:

MATERIAL LIMITATION MATERIAL SPECIFICATION

SEAMLESS WELDED

Pipe Attachment to steel having a yield strength < 42,900 psi (296 MPa)

ASTM A53, A106 GrB or C API 5L

API 5L submerged arc weld

Attachment to steel having a yield strength > 42,900 psi (296 MPa)

ASTM A106 GrB or C

Not permitted

Formed Plate Same as plate to which component is attached. Component to be fabricated using full penetration and full fusion weld.

4.1.4 Cast iron fittings shall not be employed on the shell or bottom. 4.2 Chemical Composition 4.2.1 The carbon equivalent of carbon steel plate used for the tank shell, shell nozzles, annular plates

and bottom plates, as defined by the equation below, shall meet the following limits:


GES D.01 Page 16 of 25 Rev 0 1999

Carbon equivalent (CE) = C + (Mn)/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15 = 0.45 max C = 0.28% max 5.0 FABRICATION AND ERECTION 5.1 Introduction Fabrication and erection shall comply with the requirements of API 650 code, and the additional

requirements of this specification. No fabrication shall commence until complete material certification has been received and

written approval of shop drawings, calculations, weld procedures plus welder performance qualifications has been received by the Vendor/Contractor.

Approval of material certificates and welder qualification certificates are the responsibility of the

Inspection Authority. Approval of the tank drawings, calculations, and weld procedure are the responsibility of the

Owner. The Vendor/Contractor shall notify the Owner of the proposed starting date of actual fabrication. The Vendor/Contractor shall provide erection tools for the Owner to erect and weld the tank. 5.2 Procedures 5.2.1 Plate Cutting and Preparation for Welding (a) Carbon and carbon manganese steels may be cut to size and bevelled by thermal or

mechanical methods consistent with accepted practice. (b) Care shall be taken to ensure that the weld preparations are correctly profiled. 5.2.2 Shop Inspection Shop inspection shall be made of the following tankage and components. (a) Shell plates may be inspected at the tank fabrication shop, the mill, or both, by the

Owner's Inspector and/or Inspection Authority. Inspection includes witnessing tests of physical properties.

(b) Manholes, nozzles and flush-type clean-out fittings shop welded into a tank plate or

reinforcing pad, shall be inspected by the Owner's Inspector at the tank fabricator's shop. 5.2.3 Welding Procedure and Procedure Qualifications (a) Prior to carrying out any production welding, the Vendor/Contractor shall submit to the

Owner his proposed welding procedures. (b) Welding procedures for field welding shall be established and qualified in the

Vendor/Contractor's works at a time convenient to the proposed erection programme, or at the construction site.

(c) Testing and inspection shall be as per the requirements of ASME Code, Section IX and

GES W.01.


GES D.01 Page 17 of 25 Rev 0 1999

(d) Where impact testing is required by API 650, tests shall be made for each weld procedure qualification test plate required per ASME Code, Section IX as follows:

- impact tests shall be made on the weld metal and the HAZ; - impact tests shall be conducted at the design metal temperature; - impact specimens of the weld metal and HAZ shall be taken per API 650. (e) Welding procedure qualification test welds shall be carried out under conditions

simulating the worst access and environmental conditions expected during production welding.

5.2.4 Welder's Performance Qualification Tests (a) All welders and welding operators shall be qualified in accordance with ASME Code,

Section IX and GES W.01. (b) Welder's performance qualifications shall be conducted at the construction site and in the

Vendor/Contractor's works. 5.2.5 Identification and Welders (a) All welders qualified for the work shall be assigned identification numbers. A small area

of the weld reinforcement shall be ground flat and the welder's identification mark stamped in this area. As an alternative, "as-built" drawings showing location and extent of welding carried out by each welder is acceptable.

(b) Records showing the date and the results of qualification tests conducted by each welder,

and the identification mark assigned to him, shall at all times be available for scrutiny. 5.2.6 Production Control Test Plates (a) Unless production control test plates are specified by the code or other statutory

requirements, then the Owner does not require such tests. (b) When such tests are called for by the code or other statutory requirements, they shall be

fabricated and tested in accordance with those requirements. 5.2.7 Preheat and Post-weld Heat Treatment (a) Pre-heat and post-weld heat treatment shall be in accordance with API 650 code and GES

W.03. 5.2.8 Welding (a) Where bottom plate welding is required per paragraph 3.2.3 (a), the qualification

procedure should be as follows: - 24" (600 mm) of the lap weld shall be made using the same type of electrode,

plate material and welding procedure, as will be used for the actual bottom. Three 3" (75 mm) x 18" (450 mm) tensile test strips shall be cut from this weld. The minimum breaking load of the strips shall be at least 70% of the specified or guaranteed minimum tensile strength of the unwelded plate.

(b) Tack welds for shell to bottom fillet welds, if used, shall be removed prior to welding

fittings.


GES D.01 Page 18 of 25 Rev 0 1999

(c) Weld undercuts and excessive weld metal build-up which creates steep angles at corners

of fillet welds shall be repaired. (d) Holes shall not be made in shell plate for erection purpose. (e) Mechanical caulking shall not be permitted. (f) The roof shall not have depressions that will permit accumulation of water. (g) Hardness of hot formed sections and of weld metal and the related Heat Affected Zone

(HAZ) of all welds shall not exceed 225 Brinell. 6.0 TOLERANCES Tolerance shall be in accordance with the API 650 Standard and the following additional

requirements. 6.1 Fabrication Shell plates shall have dimensional tolerances as follows:

Dimension Tolerance in mm

Length Width Difference in Diagonals

± 1/16 ± 1.5 ± 1/16 ± 1.5 ± _ ± 3.0

6.2 Curvature The tolerance for peaking and banding of shell plates is ¼" (6 mm). 6.3 Roundness The radius of the shell measured at 12" (300 mm) above the bottom corner weld shall be within

the following tolerances which represent deviation from the average radius:

Tank Diameter ft m

Tolerance on Radius in mm

< 120 < 36 120 to 210 36 to 64 > 210 > 64

½ 13 1 25 1½ 38

The circumference shall be no smaller than the theoretical circumference for the specified

diameter. The maximum permissible out-of-plumb of any single course, exclusive of banding effects, shall

be ¼" (6 mm). 7.0 INSPECTION


GES D.01 Page 19 of 25 Rev 0 1999

7.1 Procedures 7.1.1 All items of plant and equipment referenced within this specification shall be subject to

inspection by the Owner or its nominated agency. All inspection activities including those detailed in this specification shall be as agreed with the

Owner. These activities shall be incorporated within the agreed Quality Plan. 7.1.2 Approval of all NDE records are the responsibility of the Owner's Inspector at the

Vendor/Contractor's works or construction site. 7.1.3 The Vendor/Contractor shall furnish the Owner's Inspector with all relevant codes and this

specification. 7.1.4 The Vendor/Contractor shall afford the Owner's Inspector the opportunity to witness all or some

of the following quality control checks. The details shall be agreed mutually between the Inspector and the Vendor/Contractor, prior to the commencement of fabrication.

(a) Welding procedure and welder qualification work, (b) Examination of rolled and welded shells, (c) Identification of materials against Mill Test Certificates and impact tests, if required, (d) Welding examination, (e) Examination of radiographic film, (f) Internal and external examination of tanks, (g) Pressure tests, (h) Final dimensional check including peaking and banding, (i) Examination after cleaning, (j) Examination after painting, if specified, (k) Verification of code nameplate details, (l) Review and signature of Vendor/Contractor's dossiers. 7.2 Methods Inspection shall be in accordance with API 650 and the additional requirements of this

specification. 7.2.1 Visual Inspection Final inspection shall be carried out after the removal of all mill scale, dirt, grit, weld spatter,

paint, oil or other foreign matter from the tanks. It is the Vendor/Contractor's responsibility to offer the tanks in a suitable condition for the

Inspector's examination, which includes the provision of scaffolding/ladders when required. 7.2.2 Inspection of Tank Bottom


GES D.01 Page 20 of 25 Rev 0 1999

(a) Annular plate butt joints shall be 100% radiographed. (b) Bottom to shell joint shall be inspected as follows: - The inner fillet weld shall be inspected prior to welding the outside fillet weld.

Leak testing shall be performed with penetrating oil after removal of slag. Oil shall be removed before welding the outer fillet.

- The gap between the bottom shell ring and the lap welded bottom plates at radial weld location shall be a maximum of _" (3 mm).

(c) All bottom plate joints shall be tested using a vacuum box and soap suds solution. (d) Paragraph 5.3.4 (b) of API 650 shall not apply. 7.2.3 Radiographic Method of Inspecting Shell Joints (a) For low strength tank steels, radiographic examination of welding shall be per API 650

and the following additional requirements: - for shell plates over _" (22 mm), vertical joints shall be fully radiographed, - for shell plates _" (22 mm) or less, one spot radiograph shall be taken for every

50ft (15.25m) of weld and at all junctions of vertical and horizontal joints at a location selected by the Inspector,

- if submerged arc machine welding is used, the first 3 ft (1m) of complete weld made by each machine for each tank shall be 100% radiographed,

- if electro-gas welding is used, the first 8 ft (2.4m) of completed weld made by each machine shall be fully radiographed and all starts and stops in the welded joints shall be radiographed,

- quality control shall be undertaken progressively throughout the job. (b) For high strength tank steels and for tanks with a product of specific gravity greater than

1.0 radiographic requirements shall be the same as for low strength tank steels, except that all vertical seams shall be 100% radiographed.

(c) Reference markers, on each film, shall include the tank and seam numbers. Each film

shall have at least two reference markers indicating the correct location of the film on the weld.

(d) Radiograph film length shall be 10" (254mm) minimum, or full length of weld if less than

10" (254mm). (e) The following imperfections, in addition to those specified in API 650, are unacceptable: - individual slag inclusions longer than ¼" (6mm) or one-third of the plate

thickness, whichever is greater, - porosity with comet tails.


GES D.01 Page 21 of 25 Rev 0 1999

8.0 TESTING 8.1 Statutory Testing 8.1.1 The Vendor/Contractor shall conduct the hydraulic test on the tank in accordance with API 650

and this specification. 8.1.2 The tests shall be carried out in the presence of the Owner's Inspector and, if required, by the

Inspection Authority's representative. 8.1.3 The Vendor/Contractor shall submit his test procedure in writing to the Owner for approval. 8.2 Test Procedures 8.2.1 Prior to carrying out the hydrostatic test, all backing and reinforcement plates shall be leak tested

using air via a tell-tale hole with soap and water. 8.2.2 No type of preservative or paint shall be allowed to cover any joint, mechanical or welded, before

the test is complete. 8.2.3 The Vendor/Contractor shall be responsible for: (a) Hydrostatically testing the tank, including filling and emptying. If salt water is used for

testing and will remain in the tank for more than 30 days, an oxygen scavenger and a corrosion inhibitor shall be added and maintained in concentration sufficient to prevent any corrosion. After testing, the tank shall be drained and thoroughly rinsed with clean fresh water.

(b) Installing the covers of deck manholes in floating roofs, before filling. (c) Furnishing, laying and removing all lines required for testing from the water supply

point to the water disposal point. (d) Cleaning out any standing water, silt or other dirt, left in a tank after hydrostatic testing

so that the tank interior is clean and ready for operation. (e) Ensuring adequate venting arrangements during filling and draining. 8.2.4 The water filling rate for testing shall not exceed the following:

BOTTOM COURSE THICKNESS in mm

TANK PORTION FILLING RATE in/hr mm/hr

< _ 22 Top course Below top course

12 300 18 450

≥ _ 22 Top third Middle third Below Third

9 225 12 300 18 450


GES D.01 Page 22 of 25 Rev 0 1999

8.2.5 Settlement Measurements For tanks greater than 50 ft (15m) diameter, the shell and bottom settlement

measurements shall be made by the Vendor/Contractor per the following: (a) Shell settlement measurements shall be made after tank erection, prior to

hydrostatic testing and during water filling at the ½, ¾ and full levels corresponding to the maximum filling height of the tank. Settlement measurements shall be taken at equally spaced intervals of approximately 30 ft (10 m) around the tank shell on well marked locations on the annular plate or on clips welded to the shell. A record of the settlement measurements and the results of the hydrostatic test including leakage rate shall be submitted for Owner's approval.

(b) Bottom internal measurements shall be made after hydrostatic testing. Such measurements shall be made at 10 ft (3 m) spacing from the centre on the radius.

Tank Diameter ft m

Number of Diameter Axes

≤ 150 ≤ 46 4

> 150 to 225 > 46 to 69 6

> 225 to 325 > 69 to 99 8

> 325 > 99 10 Additional measurements shall be made in the annular plate region at

approximately 30 ft (10 m) intervals around the tank shell. A set of at least 3 measurements shall be made at each location commencing inward from the inside surface of the tank shell and equally spaced on a radial line. A 100% visual examination shall be made of the tank bottom to detect any localized depressions. The location and extent of depressions shall be indicated on the tank bottom plate layout drawing.

8.3 Nameplates 8.3.1 A nameplate shall be provided on each tank in accordance with API 650, Section 8.0. 8.3.2 The nameplate shall be of stainless steel stamped or engraved with the required

information. 9.0 DOCUMENTATION 9.1 Introduction 9.1.1 This section covers the documentation requirements for design, materials, fabrication,

inspection and testing. 9.2 Schedules/Reports 9.2.1 For each tank, the Vendor/Contractor shall supply with the tender, a schedule showing

submission of all documents for review and approval, proposed sub-contractors, material procurement and a production/erection programme.

9.2.2 The Vendor/Contractor shall submit with the tender a Quality Control Plan for the

contract.


GES D.01 Page 23 of 25 Rev 0 1999

9.2.3 After Purchase Order/Contract award monthly reports on design, material procurement and production progress shall be submitted to the Owner.

9.3 Data and Calculations 9.3.1 The documents shall be submitted for approval/review to the Owner and to the

Inspection Authority within the periods agreed between the Owner and the Vendor/Contractor. It shall be the responsibility of the Vendor/Contractor to ensure that the production schedule of the tank takes into account documentation submission periods, plus a three (3) week approval review period by the Owner and/or the Inspection Authority.

The Vendor/Contractor shall be responsible for obtaining approvals from the

Inspection Authority. For each tank, the Vendor/Contractor shall supply with his tender a completed

Tank Data Sheet containing all the relevant information necessary for appraisal of the mechanical design by the Owner. Also included shall be any additional drawings, specifications, etc and a list of any proposed subcontractors.

9.3.2 All calculations shall be carried out in a clear and logical manner. Where conditions

involve the use of formulae or methods not specified in the design code, the source of these formulae or methods shall be clearly referenced.

Computer calculations will only be accepted if all input is shown, together with

calculated values of intermediate terms and factors and options chosen, as well as final calculated dimensions, stresses or other values. The computer program shall be validated to the satisfaction of the Owner.

9.4 Drawings 9.4.1 The following drawings and documents shall be sent by the Vendor/Contractor to the

Owner and/or the Inspection Authority for review and approval. 9.4.2 The plating drawings, shall as a minimum, show the position of all through thickness

welds, together with material thicknesses and specifications. In addition, it shall clearly indicate the welding procedure specification which is applicable to each weld. The plating drawing may be combined with the general arrangement drawing, provided that this drawing clearly indicates the same information.

9.4.3 General arrangement drawings shall show the relative location and main dimensions of

all components including elevations and orientations of nozzles. 9.4.4 In addition, the following information shall be included on the assembly drawings: - nozzle schedule, - list of related drawings and procedures, - operating conditions, - design conditions, - corrosion allowance, - hydrotest, - NDE requirements, - design code and main standards/specifications, - weight, empty, operating, full of water, - painting requirements, - general notes covering specified requirements, - mechanical loading conditions (e.g. nozzle loads, wind, seismic etc).


GES D.01 Page 24 of 25 Rev 0 1999

9.4.5 Detail drawings, which may be included on the general arrangement, shall include

thicknesses and dimensions of all components, weld details, machining and surface finish requirements, gasket and nameplate details.

9.4.6 'As-Built' drawings may be the general arrangement drawings marked-up with the actual

as-built dimensions. 9.4.7 Drawing sizes shall conform to ISO Standards A1 to A4. All drawings shall be suitable

for microfilming on 35 mm film mounted in aperture cards. Where drawings are CAD generated, two (2) sets of copy disks shall be supplied.

9.5 Other Documents 9.5.1 Previously qualified weld procedures may be proposed by the Vendor/Contractor,

provided all welding and testing was witnessed by an independent third party and are supported by evidence of successful previous application. Evidence shall be in the form of quality records of previous applications.

9.5.2 NDE procedures shall include the general procedure to be utilised for each type of NDE

employed, together with detailed technique sheets for each applicable joint configuration proposed for each vessel.

9.6 Manuals 9.6.1 Data Book On completion of fabrication, the tank Vendor/Contractor shall submit to the

Owner, two (2) copies of the Tank Data Book which shall contain the following: - all drawings, including `As-Built' drawings, - all calculations, - NDE procedures, - hydrotest procedure and test certificate, - material test certificate, - radiography and other NDE records, - welding procedure/welder qualification certificates, - inspection certificates, - nameplate rubbing or photograph, - tank data sheets (as-built), - certificate of compliance as per API 650, Section 8.3. 9.6.2 The Vendor/Contractor shall supply the Owner one set of reproducible original

drawings. 10.0 PRIOR TO SHIPMENT 10.1 Painting and Coatings 10.1.1 Surface preparation, painting and painting materials shall be in accordance with GES X.01 and

GES X.02 and GES X.03. 10.1.2 Shop prefabricated plates intended for site welding shall be left with a 2" (50mm) margin,

unprimed. 10.1.3 Providing written agreement is obtained from the Owner, the unprimed margins may be


GES D.01 Page 25 of 25 Rev 0 1999

protected for transport, prior to site welding, by a special weld preparation coating or a weldable prefabrication primer.

10.2 Spares The Vendor/Contractor shall submit with his proposal a priced list of

recommended spares for start-up and two years normal operation. 10.3 Packing/Storage 10.3.1 This section describes the minimum requirement for the preservation and protection of the

equipment during transportation and storage, prior to unpacking. 10.3.2 The probable storage period will be specified in the Purchase Order/Contract and shall extend

from the time of despatch to the time of unpacking at site. If the storage period is not stated, a minimum period of 24 months shall be assumed. All packing shall be suitable for sea freight.

10.3.3 The following preparation for shipment shall be a minimum requirement. - After mechanical completion at the works, the materials and equipment

shall be left in a clean dry condition. - The Vendor/Contractor shall be responsible for loading and anchoring

the items to prevent damage during shipment. 10.3.4 Any additional preservation/protection requirements for sea transport shall be advised by the

Vendor/Contractor. 10.3.5 Equipment preservation and protection shall be adequate to enable the equipment to be delivered

without suffering damage or deterioration. 10.3.6 Adequate supports and bracing shall be fitted to prevent distortion of tanks and parts of tanks

during shipment. 10.4 Shipping 10.4.1 All detailed arrangements are to be covered by the Vendor/Contractor and the Purchase

Order/Contract. 10.4.2 All relevant equipment and materials shall not leave the Vendor/Contractor's works for

shipment until the release has been approved by the Owner's Inspector. 10.5 Warranty 10.5.1 The Vendor/Contractor shall warrant the tank, specified materials and services supplied against

any defect for a period of 12 months after commissioning or 24 months from the date of delivery to the site, whichever is the shorter period, or for the period stipulated in the Purchase Order/Contract.

10.5.2 Should any item be found defective, the Vendor/Contractor shall be responsible for all costs

associated with restoring the tank and equipment to the standard specified by the Purchase Order/Contract.

DATA SHEET No.

TANK P.O. / CONTRACT No.

CLIENT

PLANT LOCATION SHEET 1 of 4

SERVICE ITEM No. No. of UNITS

OPERATING AND DESIGN DATA

1 Vendor / Contractor2

3 Location 4 Fluid Stored5 Operating Press/Temp psig/°F6 SG of Liquid 7 Design Liquid Head ft8 Design Code9 Internal Design Pressure Tank in wg Coil psig10 External Design Pressure Tank in wg Coil psig11 Design Metal Temp Tank Coil 12 Min. Mechanical Design Temp. °F13 Tank Dia ft Tank Height ft14 Pumping Rate In / Out In Out usgpm15 Breathing Rate In / Out ft³/h at bar and °F16 Corrosion Allowance in 17 Inert Blanket Yes/No 18 Hazard Considerations19 20 Uniform Live Load lb/ft² Special Roof Load lb/ft²21 Foundation Type Maximum Rainfall in/hr22 Wind Design Code Wind Velocity mph23 Earthquake Design Code/ Zone /Zone 2 Earthquake Factor24

25

26 27 Shell Roof28 Bottom Reinforcement29 Nozzle Flanges Nozzle Necks30 Fittings31 Structurals32 Fixed Internals Removable Internals33 External Attachments 34 Internal Bolting / Nuts External Bolting/Nuts35 Gaskets36 Floating Roof Seal37 Internal Lining/Coating 38 Heating Coil & Nozzles 39

40

41

42

43

44

45

Revision No./DatePrepared by/DateAuthorised by/DatePurpose(C) 1999 NATIONAL OIL CORPORATION. The information on this sheet may be used only for the purpose for which it is supplied by NOC.

K:\nocspecs\SPECIFICATIONS\d-series\d-01\Dd0101r0.xls Sheet1

PAINTING

MATERIALS

DATA SHEET No.


CLIENT



CONSTRUCTION

1 Vendor / Contractor2

3 Roof Type Supported Self Supported Floating Covered Floating4 Roof Slope or Radius: Roof to Shell Details: 5 Roof Plate Seams: Lap Butt Bottom Plate Seams: 6 Bottom Plate Slope:7 Intermediate Wind Girder Top Girder Used as Walkway Yes/No8 Anchor Bolts: Yes No9 Insulation: Yes/No Thickness mm Density lb/ft³10 Weight Empty: lb11 Weight Full of Operating Fluid lb12 Weight Full of Water lb13 Nominal Capacity ft³ 14 Max. Overturning Moment at Base lb.ft15 Maximum Shear at Base lb16

17 Hydrostatic Test Full of Water18 Weld Examination Radiography 19 Supplementary Ultrasonic 20 Sectioning 21 Leak Testing Bottom 22 Shell 23 Roof 24 Mill Test Report Required / Not Required25

26

27

28 Stairway Type: Circular Straight Ladder Landings 29 Stairway Supplied By: Handrailing Yes/No 30 Walkway Width: ft Scaffold Hitch Yes/No 31 Draw Off Sump: Standard Special Yes/No32 Internal Pipe Swingline Suction Nozzle 33 Heating Coil Yes/No Surface Area ft²34 Roof Drain Hose Jointed Syphon35

36 Breather Valve: Yes/No Type: By:37 Flame Arrestor Yes/No Type: By:38 Level Indicator Yes/No Type: By:39 Dip Hatch Yes/No Type: By:40 Insulation Supports Yes/No Type: Supplied By: 41 E STANDARDS42

43

44

45 Revision No./DatePrepared by/DateAuthorised by/DatePurpose(C) 1999 NATIONAL OIL CORPORATION. The information on this sheet may be used only for the purpose for which it is supplied by NOC.


TANK ATTACHMENTS

DATA SHEET No.


CLIENT



SKETCH

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DATA SHEET No.


CLIENT



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FLANGES

SIZEREF

No.

FACETYPECLASS

ANSI B16.5

API 605

STAND

OUT

(L)

NOZZ

SCH

DISTANCE

from

REF. T.L.

(E)

ANGLE

(A)

RAD

(R)

NOZZLE

ATTACH

-MENTS

SERVICE

REINFORCING

PADS

THKO/D

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