Post on 08-Nov-2014
PROJECT SPECIFICATION TAKREER
PROJECT No 5578
Agreement no 07-5578-F-1
RUWAIS REFINERY
EXPANSION PROJECT
COMPANY Doc. No. 5578-AMD-MF-003
ENG Doc. 25418-1000-3PS-MT00-M0003
Rev. 1
INTERNATIONAL BECHTEL CO. LTD.
THE DESIGN OR PART THEREOF CONTAINED IN THIS DOCUMENT WAS DEVELOPED FOR TAKREER FOR THE PROJECT AND REMAINS THE PROPERTY OF TAKREER. ALL
INTERNATIONAL BECHTEL CO. LTD. PROPRIETARY INFORMATION OR UNDERLYING INTELLECTUAL PROPERTY UTILIZED IN THE CREATION OF THE DESIGN OR INFORMATION
CONTAINED HEREIN SHALL REMAIN THE PROPERTY OF INTERNATIONAL BECHTEL CO. LTD..
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PROJECT SPECIFICATION FOR
FIELD ERECTED WELDED
STEEL STORAGE TANKS
(API 620)
RUWAIS REFINERY EXPANSION PROJECT
FRONT END ENGINEERING DESIGN
TAKREER
PROJECT SPECIFICATION
FIELD ERECTED WELDED
STEEL STORAGE TANKS
(API 620)
TAKREER
PROJECT No 5578
Agreement no 07-5578-F-1
RUWAIS REFINERY
EXPANSION PROJECT COMPANY Doc. No. 5578-AMD-MF-003
ENG Doc. 25418-1000-3PS-MT00-M0003 Rev.1
ELECTRONIC DOCUMENTS, ONCE PRINTED, ARE NON-CONTROLLED AND MAY BECOME OUTDATED
25418-1000-3PS-MT00-M0003 Page 2 of 37
This page is a record of all revisions of this document. All previous issues are hereby
superseded and are to be destroyed.
NOTES:
Revisions after IFD are denoted as follows:
(a) By a vertical line in the right-hand margin against the revised text.
(b) By a triangle symbol for graphics, the revision number being denoted within the symbol.
Revision symbols are positioned adjacent to the revision.
(c) CHKD = Checked by, DISC = Discipline Lead, PEM = Project Engineer Manager,
PMC = Project Management Consultant.
APPROVED REV DATE
REASON
FOR ISSUE BY CHKD
DISC PEM PMC COMPANY
1 21-Oct-08 Issued For Feed KBS SK SK/GSS TSB
0 10-Sep-08 Issued For Approval KBS SK SK/GSS TSB
Signed (Initials)
TAKREER
PROJECT SPECIFICATION
FIELD ERECTED WELDED
STEEL STORAGE TANKS
(API 620)
TAKREER
PROJECT No 5578
Agreement no 07-5578-F-1
RUWAIS REFINERY
EXPANSION PROJECT COMPANY Doc. No. 5578-AMD-MF-003
ENG Doc. 25418-1000-3PS-MT00-M0003 Rev.1
ELECTRONIC DOCUMENTS, ONCE PRINTED, ARE NON-CONTROLLED AND MAY BECOME OUTDATED
25418-1000-3PS-MT00-M0003 Page 3 of 37
PARAGRAPHS REVISED THIS ISSUE
Para. No. Para. No. Para. No. Para. No.
TAKREER
PROJECT SPECIFICATION
FIELD ERECTED WELDED
STEEL STORAGE TANKS
(API 620)
TAKREER
PROJECT No 5578
Agreement no 07-5578-F-1
RUWAIS REFINERY
EXPANSION PROJECT COMPANY Doc. No. 5578-AMD-MF-003
ENG Doc. 25418-1000-3PS-MT00-M0003 Rev.1
ELECTRONIC DOCUMENTS, ONCE PRINTED, ARE NON-CONTROLLED AND MAY BECOME OUTDATED
25418-1000-3PS-MT00-M0003 Page 4 of 37
TABLE OF CONTENTS
1.0 GENERAL .................................................................................................................................7
1.1 INTRODUCTION ......................................................................................................................7
1.2 PURPOSE ..................................................................................................................................7
1.3 DEFINITIONS ...........................................................................................................................7
1.4 SUBMITTALS............................................................................................................................8
2.0 CODES, AND STANDARDS...................................................................................................10
3.0 REFERENCE DOCUMENTS ..................................................................................................11
4.0 DOCUMENT PRECEDENCE..................................................................................................13
5.0 SPECIFICATION DEVIATION/CONCESSION CONTROL ...................................................13
6.0 QUALITY ASSURANCE/QUALITY CONTROL....................................................................13
7.0 DOCUMENTATION ................................................................................................................14
8.0 SUBCONTRACTORS/SUBVENDORS ...................................................................................14
9.0 HANDLING .............................................................................................................................15
9.1 PACKAGING AND SHIPPING................................................................................................15
10.0 DESIGN ...................................................................................................................................15
10.1 GENERAL ...............................................................................................................................15
10.2 STABILITY..............................................................................................................................15
10.3 CAPACITIES ...........................................................................................................................16
10.4 DESIGN OF SHELL, ROOFS AND BOTTOM........................................................................16
10.5 EXTERNAL LOADING...........................................................................................................16
10.6 ROOF DESIGN........................................................................................................................17
10.7 DESIGN DATA ........................................................................................................................18
TAKREER
PROJECT SPECIFICATION
FIELD ERECTED WELDED
STEEL STORAGE TANKS
(API 620)
TAKREER
PROJECT No 5578
Agreement no 07-5578-F-1
RUWAIS REFINERY
EXPANSION PROJECT COMPANY Doc. No. 5578-AMD-MF-003
ENG Doc. 25418-1000-3PS-MT00-M0003 Rev.1
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11 MATERIALS............................................................................................................................19
11.1 GENERAL ...............................................................................................................................19
11.2 ADDITIONAL MATERIAL REQUIREMENTS.......................................................................19
11.3 CONSTRUCTION MATERIALS .............................................................................................19
11.4 NOTCH TOUGHNESS REQUIREMENTS..............................................................................21
11.5 MECHANICAL TESTING.......................................................................................................21
11.6 MATERIAL CERTIFICATES ...................................................................................................21
11.7 REINFORCING PLATES.........................................................................................................21
11.8 STRUCTURAL BOLTS ...........................................................................................................21
11.9 RECEIPT AND STORAGE OF MATERIALS..........................................................................22
11.10 PREPARATION OF MATERIALS ...........................................................................................22
11.11 MANUAL GAS CUTTING ......................................................................................................22
12 ERECTION ..............................................................................................................................22
12.1 ERECTION METHODS...........................................................................................................22
12.2 WIND BRACING (DURING ERECTION) ..............................................................................24
12.3 ERECTION HOLES AND ATTACHMENTS ...........................................................................24
12.4 SETTING OUT BOTTOM COURSE OF SHELL PLATES......................................................24
12.5 CHECKING OF ALIGNMENT................................................................................................24
12.6 ROOF FRAMING ....................................................................................................................25
12.7 SHELL TOLERANCES............................................................................................................25
13 FOUNDATIONS ......................................................................................................................26
13.1 CHECKING OF FOUNDATIONS............................................................................................26
13.2 ACCEPTANCE OF FOUNDATIONS.......................................................................................26
TAKREER
PROJECT SPECIFICATION
FIELD ERECTED WELDED
STEEL STORAGE TANKS
(API 620)
TAKREER
PROJECT No 5578
Agreement no 07-5578-F-1
RUWAIS REFINERY
EXPANSION PROJECT COMPANY Doc. No. 5578-AMD-MF-003
ENG Doc. 25418-1000-3PS-MT00-M0003 Rev.1
ELECTRONIC DOCUMENTS, ONCE PRINTED, ARE NON-CONTROLLED AND MAY BECOME OUTDATED
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14 OPERATIONAL FITTINGS FOR VERTICAL TANKS............................................................27
14.1 RANGE OF FITTINGS AND ACCESSORIES.........................................................................27
14.2 DESIGN OF FITTINGS, MOUNTINGS AND ACCESSORIES...............................................31
15 WELDING AND FABRICATION ............................................................................................32
15.1 WELDING ...............................................................................................................................32
15.2 FABRICATION TOLERANCES ..............................................................................................32
15.3 TANK PARTS...........................................................................................................................32
16 INSPECTION...........................................................................................................................33
16.1 GENERAL ...............................................................................................................................34
16.2 SURVEYS ................................................................................................................................34
16.3 SECTIONING ..........................................................................................................................34
17 TANK TESTING......................................................................................................................34
17.1 TANK BOTTOMS....................................................................................................................34
17.2 TANK SHELLS........................................................................................................................35
17.3 TANK ROOFS..........................................................................................................................35
17.4 REPAIR OF LEAKS.................................................................................................................35
17.5 RETESTING ............................................................................................................................36
17.6 INITIAL FILLING ...................................................................................................................36
17.7 SAFETY PRECAUTIONS........................................................................................................36
18 CLEANING AND PAINTING..................................................................................................37
18.1 CLEANING..............................................................................................................................37
18.2 PAINTING AND/OR LINING..................................................................................................37
TAKREER
PROJECT SPECIFICATION
FIELD ERECTED WELDED
STEEL STORAGE TANKS
(API 620)
TAKREER
PROJECT No 5578
Agreement no 07-5578-F-1
RUWAIS REFINERY
EXPANSION PROJECT COMPANY Doc. No. 5578-AMD-MF-003
ENG Doc. 25418-1000-3PS-MT00-M0003 Rev.1
ELECTRONIC DOCUMENTS, ONCE PRINTED, ARE NON-CONTROLLED AND MAY BECOME OUTDATED
25418-1000-3PS-MT00-M0003 Page 7 of 37
1.0 GENERAL
1.1 INTRODUCTION
This specification gives the minimum requirements for the fabrication, erection, and testing of
field erected vertical tanks in accordance with, and intended to fulfill all the requirements of API
Standard 620.
1.2 PURPOSE
This specification is intended to provide the minimum requirements to the tank VENDOR for
the design, fabrication, erection and testing of vertical tanks for the Project.
If national and/or local regulations exist in which some of the requirements may be more
stringent than in this Specification, the VENDOR shall determine by careful scrutiny which of
the requirements are the more stringent and which combination of requirements will be
acceptable as regards safety, environmental, economic and legal aspects. In all cases the
VENDOR shall inform the CONTRACTOR/COMPANY of any deviation from the
requirements of this Specification which is considered to be necessary in order to comply with
national and/or local regulations. The CONTRACTOR/COMPANY may then negotiate with
the Authorities concerned with the object of obtaining agreement to follow this specification as
closely as possible.
1.3 DEFINITIONS
For the purposes of this specification, the following definitions shall apply:
CONCESSION REQUEST - A deviation requested by the SUBCONTRACTOR or VENDOR,
usually after receiving the contract package or purchase order. Often, it refers to an authorization
to use, repair, recondition, reclaim, or release materials, components or equipment already in
progress or completely manufactured but which does not meet or comply with Takreer
requirements. A CONCESSION REQUEST is subject to COMPANY approval.
SHALL - Indicates a mandatory requirement.
SHOULD – Denotes an action or requirement which is not mandatory but which is strongly
recommended.
COMPANY - shall be defined as ABU DHABI OIL REFINING COMPANY (TAKREER)
CONTRACTOR - shall be defined as the organization to which TAKREER award the
Engineering, Procurement and Construction (EPC) phase.
MANUFACTURER/VENDOR - shall be defined as the supplier of equipment and support
services for a particular piece of equipment/package.
TAKREER
PROJECT SPECIFICATION
FIELD ERECTED WELDED
STEEL STORAGE TANKS
(API 620)
TAKREER
PROJECT No 5578
Agreement no 07-5578-F-1
RUWAIS REFINERY
EXPANSION PROJECT COMPANY Doc. No. 5578-AMD-MF-003
ENG Doc. 25418-1000-3PS-MT00-M0003 Rev.1
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SUB-CONTRACTOR - shall be defined as any person or persons, firm, partnership,
corporation or combination thereof engaged by CONTRACTOR (not being an employee of
CONTRACTOR) for supplying services to CONTRACTOR for the performance of services.
SUB-VENDOR - shall be defined as any supplier of equipment and support services for a
particular piece of equipment/package to a VENDOR.
1.4 SUBMITTALS
1.4.1 General
VENDOR’S drawings, calculations, and engineering data submitted to CONTRACTOR shall
be in the English language, refer also to Section 7.0.
1.4.2 Engineering Data Requirements
a. The VENDOR shall submit as a minimum the following engineering data for review by
CONTRACTOR:
• General arrangement and complete detail drawings as required for the fabrication of
each tank. A drawing index for each tank is required and shall be resubmitted each time
drawings are revised and reissued.
• Welding procedures (WPS) including procedure qualification record (PQR) and weld
maps.
• Heat treating procedures (if required)
• VENDOR’S design calculations.
b. Documents shall be in reproducible form and of micro filmable quality. VENDOR shall not
proceed with fabrication until notified by CONTRACTOR.
1.4.3 All subsequent revisions made by the VENDOR to the data listed in paragraph 1.4.2 shall be
resubmitted to CONTRACTOR for review.
1.4.4 CONTRACTOR reserves the right to review Certified Material Test Reports for all materials of
construction at any time during shop fabrication or field erection. VENDOR shall maintain these
documents readily available for such review and shall submit them to CONTRACTOR for final
record.
1.4.5 Review of the VENDOR’S documents by CONTRACTOR does not relieve the VENDOR of
responsibility of compliance with the applicable codes, standards, project drawings, and
specifications, or the accuracy of shop dimensions.
TAKREER
PROJECT SPECIFICATION
FIELD ERECTED WELDED
STEEL STORAGE TANKS
(API 620)
TAKREER
PROJECT No 5578
Agreement no 07-5578-F-1
RUWAIS REFINERY
EXPANSION PROJECT COMPANY Doc. No. 5578-AMD-MF-003
ENG Doc. 25418-1000-3PS-MT00-M0003 Rev.1
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1.4.6 Manufacturer’s Data Report
• As-built drawings
• Design calculations
• Radiography and NDE Reports
• Testing Reports
• Foundation Settlement Report
• Certificate of Compliance with API and this specification
• Welding Procedures and weld maps
• Material Certificates
• Name Plate to Comply with API
1.4.7 API Requirements
Upon completion of construction, provide CONTRACTOR with copies of the data sheets and a
MANUFACTURER’S Certification according to Appendix "M" of API-620, which reflects the
as-built conditions, certifying that the tank conforms to the requirements of this specification.
1.4.8 Tank VENDOR Responsibilities
a. Be responsible for complete design and construction of tanks in accordance with this
specification and other instructions furnished by the CONTRACTOR.
b. Ensure conformance to the latest Codes and legal requirements.
c. Establish tank dimensions to furnish the most economical design, unless otherwise specified.
In either case the VENDOR is encouraged to submit an alternate bid based on the most
economic design for evaluation purposes by CONTRACTOR/COMPANY.
d. Furnish and install all internals and accessories where applicable as detailed herein unless
otherwise specified on CONTRACTOR’S tank drawing.
e. Furnish complete test data and procedure including temperature limitations.
f. Furnish gauging tables in accordance with API Manual of Petroleum Measurement Standards
chapter 2 when required by CONTRACTOR’S Purchase Order. Otherwise calculated gauge
table shall be furnished.
g. Tank VENDOR shall furnish weights, material specification and thicknesses for all tanks with
his quotation.
h. The tank VENDOR shall furnish complete fabrication drawings to CONTRACTOR for
approval before starting fabrication. Each shop drawing shall be fully checked and signed as
checked before it will be accepted for approval.
TAKREER
PROJECT SPECIFICATION
FIELD ERECTED WELDED
STEEL STORAGE TANKS
(API 620)
TAKREER
PROJECT No 5578
Agreement no 07-5578-F-1
RUWAIS REFINERY
EXPANSION PROJECT COMPANY Doc. No. 5578-AMD-MF-003
ENG Doc. 25418-1000-3PS-MT00-M0003 Rev.1
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i. PROJECT drawings shall show the location of fittings.
j. VENDOR standard locations for fittings on floating roofs will be followed, unless other
instructions are given.
k. Internal and external Cathodic protection system as per tank data sheet.
l. Internal and external lining / painting (Refer Section 18) wherever specified in data sheet.
2.0 CODES, AND STANDARDS
It shall be the VENDOR’S responsibility to be, or to become, knowledgeable of the
requirements of the referenced Codes and Standards.
The following codes and standards shall, to the extent specified herein, form a part of this
specification. 15th January 2008 is the effective date for all codes and standards i.e. the code or
standard valid on that date shall be the one to be used.
American Petroleum Institute (API):
API Standard 620, 10th Edition, + Addendum, June 2004- Design and Construction of Large,
Welded, Low-Pressure Storage Tanks
API Standard 653, Appendix B - Evaluation of Tank Bottom Settlement
API Standard 2000 - Venting Atmospheric and Low-Pressure Storage Tanks, Non-Refrigerated and
Refrigerated
API MPMS 2.2A - Manual of Petroleum Measurement Standards Chapter-2.2A – Tank
Calibration. - Measurement and Calibration of Upright Cylindrical Tanks by the Manual Strapping
Method
API MPMS 2.2B - Manual of Petroleum Measurement Standards Chapter-2.2B – Tank Calibration.
- Calibration of Upright Cylindrical Tanks Using the Optical Reference Line Method
Federal National and Other Codes:
National Fire Protection Association Code No. 30 - Flammable and Combustible Liquids
American Society of Civil Engineers
Uniform Building Code
ASME/ANSI B 16.47 Large Diameter Steel Flanges
American National Standards Institute (ANSI):
ASME B1.1 - Unified Inch Screw Threads
TAKREER
PROJECT SPECIFICATION
FIELD ERECTED WELDED
STEEL STORAGE TANKS
(API 620)
TAKREER
PROJECT No 5578
Agreement no 07-5578-F-1
RUWAIS REFINERY
EXPANSION PROJECT COMPANY Doc. No. 5578-AMD-MF-003
ENG Doc. 25418-1000-3PS-MT00-M0003 Rev.1
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ASME B16.5 - Pipe Flanges and Flanged Fittings
European Committee for Standardization (EN):
EN 10204 - Types of Inspection Documents - Metallic Products
International Organization for Standardization (ISO):
ISO 9001 – 2000 - Quality Management System Requirements
ISO 9004 – 2000 - Quality Management Guidelines for Performance Improvement System
ISO 19011 - Guidelines for Quality and/or Environmental System Auditing
3.0 REFERENCE DOCUMENTS
The following reference documents, to the extent specified herein, form a part of this
specification.
Project Standard Specifications:
Project Specifications Takreer Doc’t No. Specification Title
25418-0000-3PS-S000-C0001 5578-AMD-CU-002 Structural Engineering Design Criteria
25418-0000-3PS-SS01-C0001 5578-AMD-CU-020 Structural Steel Fabrication
25418-1000-3PS-MT00-M0001 5778-AMD-MF-001 Design Basis-Tanks
25418-0000-3PS-NN00-N014 5578-AMD-MN-001 Insulation
25418-1000-3PS-M000-M0007 5578-AMD-MU-012 Requirements for Manufacturing Data
Report For Non-pressure Vessel
Equipment
25418-1000-3PS-M000-M0011 5578-AMD-MU-013 Criticality Rating System
25418-1000-3PS-M000-M0008 5578-AMD-MU-014 Minimum Shop Inspection and Certification Requirements
25418-1000-3PS-H002-Y0001 5578-AMD-MU-200 Fire Protection Design Philosophy
25418-1000-3PS-H002-Y0002 5578-AMD-MU-201 Water Spray Fire Protection Systems
25418-1000-3PS-H002-Y0003 5578-AMD-MU-202 Foam Fire Protection Systems
25418-1000-3PS-NW00-N0003 5578-AMD-MW-003 Welding of Storage Tanks
25418-1000-3PS-NX00-N0001 5578-AMD-MX-001 External Painting
25418-1000-3PS-NX00-N0010 5578-AMD-MX-002 Galvanizing
25418-1000-3PS-NLLG-N0001 5578-AMD-MX-004 Internal Lining
25418-1000-3PS-N001-N0001 5578-AMD-MY-002 Cathodic Protection for on grade tank bottom and buried piping.
TAKREER
PROJECT SPECIFICATION
FIELD ERECTED WELDED
STEEL STORAGE TANKS
(API 620)
TAKREER
PROJECT No 5578
Agreement no 07-5578-F-1
RUWAIS REFINERY
EXPANSION PROJECT COMPANY Doc. No. 5578-AMD-MF-003
ENG Doc. 25418-1000-3PS-MT00-M0003 Rev.1
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25418-1000-3PS-MFA0-M0001 5578-AMD-MV-005 Side Entry Mixers for Storage Tanks
25418-1000-3PS-N001-N0004 5578-AMD-MY-007 Cathodic Protection of Internal surface of
tank
25418-1000-3PS-NW00-N0008 5578-AMD-MW-008 Metallic Materials.
25418-1000-3PS-NW00-N0004 5578-AMD-MW-004 Materials and Fabrication Requirements
for Carbon Steel Piping and Equipment in
Severe Service.
Project Standard Drawings:
Project Drawing Takreer Drawing No. Drawing Title
25418-1000-3SD-MV00-M0025 5578-STD-MD-B-040 Earthing Clips For, Tanks, Vessels, and Supporting Structures
25418-1000-3SD-MT00-M0001 5578-STD-MF-B-001 Handrails for Cone Roof Tanks
25418-1000-3SD-MT00-M0002 5578-STD-MF-B-004 Product Drain & Water Draw Off
25418-1000-3SD-MT00-M0019 5578-STD-MF-B-005 Floating Suctions for Vertical Tanks - 4 inch, 6 inch & 8 inch
25418-1000-3SD-MT00-M0020 5578-STD-MF-B-006 Typical Swing Pipe - 3 inch up to 20 inch
Equipment
25418-1000-3SD-MT00-M0021 5578-STD-MF-B-007 Typical Winches for Swing Pipes
25418-1000-3SD-MT00-M0003 5578-STD-MF-B-008 Spiral-Type Staircase Provided With Stair
Treads of Galvanized Grating
25418-1000-3SD-MT00-M0007 5578-STD-MF-B-012 Level Gauge Pole for Fixed Roof Tanks
(Execution for Custody Transfer)
25418-1000-3SD-MT00-M0008 5578-STD-MF-B-013 Combined Guide Pole/Level Gauge Pole
for Floating Roof Tanks (for Custody
Transfer)
25418-1000-3SD-MT00-M0010 5578-STD-MF-B-015 Vertical Ladder
25418-1000-3SD-MT00-M0012 5578-STD-MF-B-017 Level Gauge Pole for Fixed Roof Tanks (Non Custody Transfer)
25418-1000-3SD-MT00-M0013 5578-STD-MF-B-018 Nameplate with Bracket for Tanks
25418-1000-3SD-MT00-M0015 5578-STD-MF-B-021 Subsurface Foam Systems for Flammable
and Combustible Liquids
25418-1000-3SD-MT00-M0016 5578-STD-MF-B-022 Semi-subsurface Foam System for
Flammable and Combustible Liquids
25418-1000-3SD-MT00-M0018 5578-STD-MF-B-024 Methods Of Tank Erection
TAKREER
PROJECT SPECIFICATION
FIELD ERECTED WELDED
STEEL STORAGE TANKS
(API 620)
TAKREER
PROJECT No 5578
Agreement no 07-5578-F-1
RUWAIS REFINERY
EXPANSION PROJECT COMPANY Doc. No. 5578-AMD-MF-003
ENG Doc. 25418-1000-3PS-MT00-M0003 Rev.1
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4.0 DOCUMENT PRECEDENCE
The VENDOR shall notify the CONTRACTOR of any apparent conflict between this
specification, the related data sheets, the Codes and Standards and any other specifications
noted herein. Resolution and/or interpretation precedence shall be obtained from the
CONTRACTOR in writing before proceeding with the design/manufacture.
In case of conflict, the order of precedence is:
A – Datasheets
B – Specification
C - Codes and Standards
D – Standard Drawings
5.0 SPECIFICATION DEVIATION/CONCESSION CONTROL
Any technical deviations to this specification and its attachments including, but not limited to, the
Data Sheets and Narrative Specifications shall be sought by the VENDOR only through
CONCESSION REQUEST format. CONCESSION REQUESTS require CONTRACTOR’S and
COMPANY'S review/approval, prior to the proposed technical changes being implemented.
Technical changes implemented prior to COMPANY approval are subject to rejection.
6.0 QUALITY ASSURANCE/QUALITY CONTROL
VENDOR’S proposed quality system shall fully satisfy all elements of ISO 9001 – 2000 and ISO
9004 – 2000 with due regard to ISO 19011. The quality system shall provide for the planned and
systematic control of all quality related activities performed during design, development,
production, installation or servicing (as appropriate to the given system).
Implementation of the system shall be in accordance with the Contractor’s Quality Manual and
Project Specific Quality Plan, which shall both together with all related/reference procedures be
submitted to COMPANY for review, comment and approval as required by purchase/contract
documents.
The Criticality Rating (CR) System outlined in Project Specification 5578-AMD-MU-013 shall be
used by CONTRACTOR or CONTRACTOR’S designee to develop the design checking levels and
minimum requirements for shop inspection, testing and material certification given in Project
Specification 5578-AMD-MU-014.
Field inspection of partial or fully field fabricated tanks shall be per API-620, and as agreed to by
CONTRACTOR/COMPANY and tank VENDOR.
TAKREER
PROJECT SPECIFICATION
FIELD ERECTED WELDED
STEEL STORAGE TANKS
(API 620)
TAKREER
PROJECT No 5578
Agreement no 07-5578-F-1
RUWAIS REFINERY
EXPANSION PROJECT COMPANY Doc. No. 5578-AMD-MF-003
ENG Doc. 25418-1000-3PS-MT00-M0003 Rev.1
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7.0 DOCUMENTATION
VENDOR shall submit the type and quantity of drawings and documentation for
CONTRACTOR’S authorization or information as listed in the individual Material Requisitions
and Purchase Orders/Subcontracts, refer also to Paragraph 1.4.
Mutual agreement on scheduled submittal of drawings and engineering data shall be an integral
part of any formal Purchase Order/Subcontract.
Comments made by CONTRACTOR on drawing submittal shall not relieve VENDOR or
SUBVENDORS of any responsibility in meeting the requirements of the specifications. Such
comments shall not be construed as permission to deviate from requirements of the Purchase Order
unless specific and mutual agreement is reached and confirmed in writing.
Each drawing shall be provided with a title block in the bottom right-hand corner incorporating the
following information:
1. Official trade name of the company.
2. VENDOR’S drawing number.
3. Drawing title giving the description of contents whereby the drawing can be identified.
4. A symbol or letter indicating the latest issue or revision.
5. PO number and item tag numbers.
Revisions to drawing shall be identified with symbols adjacent to the alterations, a brief description
in tabular form of each revision shall be given, and if applicable, the authority and date of the
revision shall be listed. The term "Latest Revision" shall not be used.
8.0 SUBCONTRACTORS/SUBVENDORS
The VENDOR shall assume unit responsibility and overall guarantee for the equipment package
and associated equipment.
The VENDOR shall transmit all relevant purchase order documents including specifications to his
SUBVENDORS and SUBCONTRACTORS.
It is the VENDOR’S responsibility to enforce all Purchase Order and Specification requirements on
his SUBVENDORS and SUBCONTRACTORS.
The VENDOR shall submit all relevant SUBVENDOR and SUBCONTRACTOR drawings and
engineering data to the CONTRACTOR.
The VENDOR shall obtain and transmit all SUBVENDOR and SUBCONTRACTOR warranties to
the CONTRACTOR/COMPANY, in addition to the system warranty.
TAKREER
PROJECT SPECIFICATION
FIELD ERECTED WELDED
STEEL STORAGE TANKS
(API 620)
TAKREER
PROJECT No 5578
Agreement no 07-5578-F-1
RUWAIS REFINERY
EXPANSION PROJECT COMPANY Doc. No. 5578-AMD-MF-003
ENG Doc. 25418-1000-3PS-MT00-M0003 Rev.1
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25418-1000-3PS-MT00-M0003 Page 15 of 37
9.0 HANDLING
9.1 PACKAGING AND SHIPPING
Preparation for shipment of materials to the jobsite shall be in accordance with the VENDOR’S
standards and as noted herein. VENDOR shall be solely responsible for the adequacy of the
preparation for shipment provisions with respect to materials and application, and to provide
equipment at the destination in ex-works condition when handled by commercial carriers.
Adequate protection shall be provided to prevent mechanical damage and atmospheric corrosion in
transit and at the jobsite. High humidity, rain, dust, sand, salt air, and salt water are some of the
adverse conditions to be allowed for at the jobsite.
10.0 DESIGN
10.1 GENERAL
VENDOR shall design, fabricate, inspect, test, and certify tanks in accordance with API 620,
except where modified as specified. Obtain CONTRACTOR approval for deviations, exceptions,
and substitutions to API, including those that are permitted, subject to approval of
CONTRACTOR/COMPANY.
a. Corrosion allowance, when specified, shall be added to calculated shell and roof thicknesses
and minimum bottom plate thicknesses. The total thickness of shell or roof shall not be less
than the minimum permitted by API 620.
b. The provisions of NFPA No. 30, Flammable and Combustible Liquids Code, shall be complied
with in the tank design.
c. Vents shall be sized in accordance with API Standard 2000 unless otherwise specified.
d. All connections shall be flanged. Minimum nominal diameter shall be DN 50.
e. Flange bolt hole orientation for all tank nozzles including tangential and branch connections
shall straddle the natural tank centerlines.
f. Heating coil pipes (when specified) shall be of seamless quality with Schedule 80 as a
minimum and connected by butt welded joints. Heating coil supports shall not be welded to
tank bottom; however, they shall be rigidly supported.
10.2 STABILITY
For calculations of tank stability in strong winds and seismic events, the velocities and data given
in Structural Engineering Criteria 5578-AMD-CU-002 shall be used.
Unstable tanks shall be provided with anchor bolts and concrete foundation rings. Uplift is caused
by the internal vapor pressure acting against the underside of the roof, in conjunction with wind
load. A stability calculation shall be made to determine the number of anchor bolts required.
TAKREER
PROJECT SPECIFICATION
FIELD ERECTED WELDED
STEEL STORAGE TANKS
(API 620)
TAKREER
PROJECT No 5578
Agreement no 07-5578-F-1
RUWAIS REFINERY
EXPANSION PROJECT COMPANY Doc. No. 5578-AMD-MF-003
ENG Doc. 25418-1000-3PS-MT00-M0003 Rev.1
ELECTRONIC DOCUMENTS, ONCE PRINTED, ARE NON-CONTROLLED AND MAY BECOME OUTDATED
25418-1000-3PS-MT00-M0003 Page 16 of 37
10.3 CAPACITIES
10.3.1 Capacities specified for tanks are minimum net working capacities:
a. Total liquid capacity, nominal liquid capacity and volume of vapor space shall be as per API 620 Para
3.2 and 5.1.4.
10.4 DESIGN OF SHELL, ROOFS AND BOTTOM
Tank shell, roof and bottom shall be designed per API-620, Para. 5.10.
10.4.1 Limits for Shell Plate Thickness
a. The nominal/minimum thickness of the shell plates shall be as per API-620, Para.. 5.10.3 and
5.10.4.
b. No course shall have a thickness less than that of the course above, regardless of the material of
construction.
c. The vertical joints between shell plates shall not be in alignment within any three consecutive
courses, and the distance between vertical joints in adjacent courses shall be approximately
one-third of the plate length. If this is not possible, the distance between vertical joints in
adjacent courses shall not be less than 0.3 m.
10.4.2 Bottom Design
a. Bottom plates shall be at least 6 mm (1/4 in.) minimum thick exclusive of corrosion allowance
as per API-620, Para. 5.9.4.2.
b. Pad Plates
Pad plates fixed to the tank bottom shall be used at all supports and be continuously welded.
Pad plates should be of circular shape; if square or rectangular plates are used, they shall have
their corners rounded (radius at least 5 times the plate thickness).Reinforcement plate / pad for
a flush-type side wall connection shall confirm to API 620 Para 5.27.4.
c. All storage tank bottoms are to be cathodically protected against soil side corrosion per
specification 5578-AMD-MY-002.
NOTE: Tank VENDOR shall be aware of the test requirements to ensure that the cathodic
protection system has not been damaged or shorted during fabrication of the bottom
plates, per the above specification.
10.4.2 Compression Rings
Compression rings shall be designed as per API 620 Para 5.12.4 & 5.12.5.
10.5 EXTERNAL LOADING
10.5.1 Wind Girders
a. General
TAKREER
PROJECT SPECIFICATION
FIELD ERECTED WELDED
STEEL STORAGE TANKS
(API 620)
TAKREER
PROJECT No 5578
Agreement no 07-5578-F-1
RUWAIS REFINERY
EXPANSION PROJECT COMPANY Doc. No. 5578-AMD-MF-003
ENG Doc. 25418-1000-3PS-MT00-M0003 Rev.1
ELECTRONIC DOCUMENTS, ONCE PRINTED, ARE NON-CONTROLLED AND MAY BECOME OUTDATED
25418-1000-3PS-MT00-M0003 Page 17 of 37
Tanks may require intermediate wind girders to maintain roundness over the full height of the
tank shell under wind load condition. The need for these wind girders and the required number
shall be calculated as indicated in API-620 Para 5.10.6.
b. Location of Wind Girders
The girders on the shell shall be located in accordance with API-620 Para 5.10.6, calculating
unstiffened height of shell.
In view of possible corrosion, which often occurs at the upper part of the tank shell, the girders
should be installed as high as permitted by the calculation results.
c. Design of Wind Girders
The minimum sizing for intermediate wind girders shall be per API-620 Para 5.10.6.6.
Continuous welds shall be used for all connections of secondary wind girders. Full penetration
butt welds shall be used for joining sections of the wind girder ring.
A mouse hole (20 mm radius) shall be made in the joining sections next to the tank shell to
prevent fusion between butt weld and tank shell.
10.5.2 Other Loadings
All other loadings as specified in API 620 Para 5.4 shall be considered during design of tank.
10.6 ROOF DESIGN
10.6.1 Supporting of Roof Plates
a) Design of roof shall meet all requirements of API 620 Para 5.12.
b) Lateral braces between outer bay rafters must be provided when unsymmetrical structural
shapes are used for rafters and the tanks are located in areas subject to earthquake. The bracing
must be adequately sized for the seismic zone specified, and shall not be less than the minimum
required per API Standard 620.
c) For tanks specified with cone roofs, VENDOR may propose an alternate for supplying
self-supporting dome or umbrella roof when feasible and more economical.
10.6.2 Roof Plates
a. Joining of Plates
Laps shall be arranged with the higher plates (i.e., those nearer the tank center) underneath the
lower plates, in order to avoid the risk of condensed moisture becoming trapped in the lap on
the underside of the roof. However, if the roof plates are welded on both the internal and
external laps the tank VENDOR may propose an alternate.
Roofs of tanks shall be welded on both the internal and external laps, to facilitate external
coating and internal lining, when an internal lining requirement is indicated on the PROJECT
tank data sheets.
TAKREER
PROJECT SPECIFICATION
FIELD ERECTED WELDED
STEEL STORAGE TANKS
(API 620)
TAKREER
PROJECT No 5578
Agreement no 07-5578-F-1
RUWAIS REFINERY
EXPANSION PROJECT COMPANY Doc. No. 5578-AMD-MF-003
ENG Doc. 25418-1000-3PS-MT00-M0003 Rev.1
ELECTRONIC DOCUMENTS, ONCE PRINTED, ARE NON-CONTROLLED AND MAY BECOME OUTDATED
25418-1000-3PS-MT00-M0003 Page 18 of 37
To prevent corrosion due to sand and salt buildups adjacent to welds on the top-side, a smooth
taper shall be built up with a compound such as an epoxy sealant before painting as specified in
specification 5578-AMD-MX-001.
10.7 DESIGN DATA
10.7.1 Wind Load
Wind design shall be in accordance with the American Society of Civil Engineers Code. Analysis
and interpretation of the Code shall be in accordance with Project Specification 5578-
AMD-CU-002, Structural Engineering Design Criteria.
10.7.2 Earthquake Load
Earthquake design for tanks shall be in accordance with the ASCE-7-05 code. Analysis and
interpretation of the code shall be in accordance with Project Specification 5578-AMD-CU-002,
Structural Engineering Design Criteria.
10.7.3 Design Climatic Conditions are as follows
Rainfall : 20 mm average per year
100 mm maximum per year
60 mm maximum for one hour period
Temperature : a. Winter: 5o C
Solar (Black Body): 87o C
b. Summer: 50o C
c. Minimum Design Metal Temperature: -15°C maximum
Snow load : - None
Maximum soil bearing pressure = 1.6 kg/cm2 (to be confirmed upon receipt of Project Soil
Report)
10.7.4 Units Of Measurement
QUANTITY UNIT ABBREVIATION
Area Square meter m2
Density kilograms per cubic meter kg/m3
Flow - Liquid cubic meter per hour m3/hr
Flow - Gas and Vapor normal cubic meter per Nm3/hr
TAKREER
PROJECT SPECIFICATION
FIELD ERECTED WELDED
STEEL STORAGE TANKS
(API 620)
TAKREER
PROJECT No 5578
Agreement no 07-5578-F-1
RUWAIS REFINERY
EXPANSION PROJECT COMPANY Doc. No. 5578-AMD-MF-003
ENG Doc. 25418-1000-3PS-MT00-M0003 Rev.1
ELECTRONIC DOCUMENTS, ONCE PRINTED, ARE NON-CONTROLLED AND MAY BECOME OUTDATED
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hour
Force kilogram force kgf
Length Millimeter mm
Length Meter m
Mass Kilogram kg
Mass Ton te or t
Pressure - Design kilograms per square
centimeter gauge
kg/cm2 g*
Pressure - Operating kilograms for square
centimeter gauge
kg/cm2 g*
Temperature degree centigrade °C
Viscosity - Dynamic Centipoise cP
Volume Cubic meter m3
*kg/cm2 = gauge
11 MATERIALS
11.1 GENERAL
All materials shall conform with the requirements of API Standard 620 and 5578-AMD-MW-008.
Material for Severe service shall be in accordance with 5578-AMD-MW-004.
All materials of construction not specified on PROJECT drawings and material substitutions
equivalent to the ASTM materials specified in API Standards shall be approved by
CONTRACTOR/COMPANY before use. Tank VENDOR shall submit for approval complete
descriptions of the chemical and mechanical properties.
11.2 ADDITIONAL MATERIAL REQUIREMENTS
When medium high tensile steel, as defined in Para. 11.2.4, is used, additional requirements are
specified for weld details and weld inspection; see Welding of Storage Tank Specification 5578-
AMD-MW-003.
11.3 CONSTRUCTION MATERIALS
11.2.1 Bottom Plates and Roof Plates
A certificate from the steel mill in accordance with Para 11.6 is required to confirm that the steel is
made according to an ASTM specification allowable by this specification, and API-620. The steel
shall contain not more than 0.23% carbon content.
11.2.2 Shell Plates and Bottom Annular Plates
TAKREER
PROJECT SPECIFICATION
FIELD ERECTED WELDED
STEEL STORAGE TANKS
(API 620)
TAKREER
PROJECT No 5578
Agreement no 07-5578-F-1
RUWAIS REFINERY
EXPANSION PROJECT COMPANY Doc. No. 5578-AMD-MF-003
ENG Doc. 25418-1000-3PS-MT00-M0003 Rev.1
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The steel shall contain not more than 0.23% carbon, 0.05% sulfur and 0.05% phosphorus, as
determined by ladle analysis.
The steel shall have a guaranteed minimum ultimate tensile strength of at least 363 N/mm2 and a
maximum ultimate tensile strength of not more than 510 N/mm2. The steel shall have a guaranteed
yield strength of at least 206 N/mm2. The steel shall have an elongation not less than 22%.
Mill certificates shall be supplied and shall indicate the steel making process as well as the
parameters stated in the material specification and this specification.
11.2.3 Specifications for Medium High Tensile Steel
Medium high tensile steels, as defined in Para. 11.2.4, may be used for the shells and bottom
annular plates of medium and large storage tanks (15,000 m3 capacity and over).
All steel shall be made by the basic oxygen or electric furnace process. Bessemer or Rimming
steels shall not be used.
11.2.4 Properties of Medium High Tensile Steel
For the purposes of this specification, steels are considered to be medium high tensile if they have a
guaranteed minimum yield strength in the range of 295-355 N/mm2 and a guaranteed ultimate
tensile strength in the range of 470-620 N/mm2.
The steel shall be fully killed and normalized to produce a fine grain structure. Semi-killed steel
may be used only for plates up to 16 mm in thickness.
The ratio of yield strength to tensile strength of the plates shall not exceed 0.85.
The steel shall have an elongation of not less than 22%.
11.2.5 Chemical Analysis of Medium High Tensile Steel
The ladle analysis of the steel shall comply with the following requirements:
C 0.23% max.
Mn 1.50% max.
Si 0.40% max.
P 0.04% max.
S 0.04% max.
P + S 0.07% max.
V 0.10% max.
Nb 0.04% max.
Nb + V 0.10% max.
TAKREER
PROJECT SPECIFICATION
FIELD ERECTED WELDED
STEEL STORAGE TANKS
(API 620)
TAKREER
PROJECT No 5578
Agreement no 07-5578-F-1
RUWAIS REFINERY
EXPANSION PROJECT COMPANY Doc. No. 5578-AMD-MF-003
ENG Doc. 25418-1000-3PS-MT00-M0003 Rev.1
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11.2.6 Carbon equivalent (for all welded components not in Severe Service)
Carbon content of carbon and carbon-manganese steels shall not exceed 0.23%, except for forgings
and castings, where this may be relaxed to 0.25%. For pressure containing components, the carbon
equivalents (CE) shall not exceed 0.43 given by:
15
Ni+Cu+
5
V+Mo+Cr+
6
Mn+C = C.E
11.4 NOTCH TOUGHNESS REQUIREMENTS
Notch toughness for shell plates, bottom annular plates, (etc.) shall be in accordance with API-620
Para 4.2.4.2 and 4.2.5. Toughness requirements for pipes, flanges and forgings shall be as per API
620 Para 4.3.5.
11.5 MECHANICAL TESTING
Mechanical testing for materials used in the construction of tanks shall be in accordance with API
Standard 620 and respective ASTM material standarad.
11.6 MATERIAL CERTIFICATES
VENDOR shall furnish material certificates in accordance with the requirements of EN10204
(formerly DIN 50049). The type of certificate required (‘2.1’, ‘2.2’, ‘3.1’ or ‘3.2’) is determined
by the inspection class assigned to the type of equipment or material. Component parts of a piece
of equipment may require different types of certificates. For specific requirements refer to the
individual material requisition and purchase order/subcontract.
Certificates shall show all the properties of materials guaranteed by its specification and any
additional requirements. They shall be submitted to the CONTRACTOR prior to commencement
of fabrication.
11.7 REINFORCING PLATES
Reinforcing plates shall be made from steel of the same quality as the shell plates to which they are
welded.
11.8 STRUCTURAL BOLTS
Except as specified in API 620, bolts shall be regular unfinished machine bolts with one heavy
semi-finished hex nut or studs with 2 nuts. Bolt and nut threads shall conform to ANSI B1.1
coarse, Class 2A and Class 2B respectively
TAKREER
PROJECT SPECIFICATION
FIELD ERECTED WELDED
STEEL STORAGE TANKS
(API 620)
TAKREER
PROJECT No 5578
Agreement no 07-5578-F-1
RUWAIS REFINERY
EXPANSION PROJECT COMPANY Doc. No. 5578-AMD-MF-003
ENG Doc. 25418-1000-3PS-MT00-M0003 Rev.1
ELECTRONIC DOCUMENTS, ONCE PRINTED, ARE NON-CONTROLLED AND MAY BECOME OUTDATED
25418-1000-3PS-MT00-M0003 Page 22 of 37
11.9 RECEIPT AND STORAGE OF MATERIALS
The erection VENDOR shall inspect and keep stock of all materials delivered to site and be fully
responsible for their safekeeping. All fittings, valves, plates, etc., shall be properly laid out on
wooden supports clear of the soil. Special care shall be taken that damage does not occur to joint
faces of valves and flanges or to beveled ends of fittings.
11.10 PREPARATION OF MATERIALS
All materials shall be examined, cleaned and repaired as necessary at the site before being erected,
to ensure, that any damage incurred in transit is made good to the satisfaction of the
CONTRACTOR/COMPANY’S representative. Particular attention shall be paid to the removal of
buckles and distortions in the shell and bottom plates.
11.11 MANUAL GAS CUTTING
Manual gas cutting may be used for trimming the corners of bottom or roof plates where two
lapped joints intersect, and for cutting openings for fittings positioned on site.
Manual gas cutting shall not be used for any other purpose without the approval of
CONTRACTOR/COMPANY’S representative.
12 ERECTION
12.1 ERECTION METHODS
12.1.1 General
The main methods of erecting welded vertical tanks are outlined in this section and illustrated in
Project Standard Drawings (see Section 3.0).
Welded vertical tanks can be erected satisfactorily in several ways; no one particular system of
erection procedure is specified for use.
Erection VENDORS normally have a specific individual method, which they have adopted as the
result of experience, and have developed the erection technique most suitable for economical
working and good workmanship by their field crews.
Provided that the erection VENDOR employs a method which is known to give good results and
that the recommended sequences of erection and welding are followed, the method may be deemed
satisfactory.
To build tanks which are of sound quality, good appearance and free from excessive buckles or
distortion, correct welding sequences shall be adhered to and adequate supervision provided.
Therefore, to make certain that poor practices will not be followed and that care will be taken to
ensure satisfactory construction, VENDORS shall outline their method of erection for approval by
the CONTRACTOR/ COMPANY before a contract is placed. The main well-known methods of
erection are given below.
TAKREER
PROJECT SPECIFICATION
FIELD ERECTED WELDED
STEEL STORAGE TANKS
(API 620)
TAKREER
PROJECT No 5578
Agreement no 07-5578-F-1
RUWAIS REFINERY
EXPANSION PROJECT COMPANY Doc. No. 5578-AMD-MF-003
ENG Doc. 25418-1000-3PS-MT00-M0003 Rev.1
ELECTRONIC DOCUMENTS, ONCE PRINTED, ARE NON-CONTROLLED AND MAY BECOME OUTDATED
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12.1.2 Progressive Assembly And Welding
In the progressive assembly method, the bottom plates are assembled and welded first. Thereafter
the shell plates are erected, held in place, tacked and completely welded. This shall be done course
by course, working upwards to the top curb angle. No course shall be added as long as the
previous course has not been entirely welded.
The erection and completion of the roof framing and roof plates then follow. See Project Standard
Drawings (see Section 3.0).
12.1.3 Complete Assembly Followed by Welding of Horizontal Seams
In the complete assembly method, the bottom plates are assembled and welded first. Thereafter the
shell plates are erected, held in place, tacked and only the vertical seams completely welded,
leaving the horizontal seams un welded. This shall be done course by course, working upwards to
the top curb angle. No course shall be added as long as the vertical seams of the previous course
have not been entirely welded.
The erection and completion of the roof framing and roof plates then follow. Finally the horizontal
seams are welded, working upwards from the bottom course or downwards from the top curb
angle. See Project Standard Drawings (see Section 3.0).
12.1.4 Jacking-Up Method
Some VENDORS employ a system of erection in which the bottom plates are completed, the top
course is erected on the bottom plates, the roof framing and sheeting are completed and a number
of jacks are then assembled around the structure. By means of these jacks, the completed top
course together with the roof framing and sheeting is lifted to a height sufficient to insert the next
lower course. The jacking method and the supporting of the partly erected shell shall have no
adverse effect on the roundness of the shell.
The welding is completed at each stage of lift until all courses of the shell plates have been inserted
and the finished height is reached.
The final operation is the welding of the bottom course to the bottom plates. See Project Standard
Drawings (see Section 3.0.).
12.1.5 Prefabrication
For a hazardous location and/or close to existing tanks already storing light products, tanks can
be prefabricated and moved to their permanent site either by:
• Prefabrication of the tank in the workshop. The maximum dimensions depend on the
possibilities and limitations with respect to transport.
Generally this method shall be limited to tanks with diameters up to 12 meters.
TAKREER
PROJECT SPECIFICATION
FIELD ERECTED WELDED
STEEL STORAGE TANKS
(API 620)
TAKREER
PROJECT No 5578
Agreement no 07-5578-F-1
RUWAIS REFINERY
EXPANSION PROJECT COMPANY Doc. No. 5578-AMD-MF-003
ENG Doc. 25418-1000-3PS-MT00-M0003 Rev.1
ELECTRONIC DOCUMENTS, ONCE PRINTED, ARE NON-CONTROLLED AND MAY BECOME OUTDATED
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• Prefabrication of the tank on a temporary foundation at a safe location nearby. The
complete tank is then moved to its permanent foundation, e.g. by crane, on rollers or by
air cushion.
• The water test shall be carried out when the tank is standing on its permanent
foundation.
This method may only be used with the written agreement of the
CONTRACTOR/COMPANY.
12.2 WIND BRACING (DURING ERECTION)
During erection, tanks shall be safeguarded adequately against distortion or damage due to wind
pressure, by the provision of suitable steel wire guys or braces.
A minimum of one guy every 8 m of circumference is recommended.
These shall remain in place until welding of the shell plates and erection of the roof framing has
been completed, or, with open top tanks, until the wind girder has been completed.
Particular attention shall be given to the reliability of anchor blocks for the guys especially in weak,
muddy soils and due to soil settlement.
12.3 ERECTION HOLES AND ATTACHMENTS
Holes in plate work, to assist in erection, are not permitted.
Lugs, nuts, clamps, and other devices to assist in erection may be attached to the tank plates by
welding, but all such attachments required only for the purposes of erection shall ultimately be
removed and any noticeable projections of weld metal remaining shall be carefully ground away.
Plates shall not be gouged or torn in the process of removing attachments, and any indentations
caused thereby shall be filled with weld metal and ground flush with the plate surface.
Magnetic clamps, if used on the shell plates, shall be checked for residual magnetism and
demagnetized, if required.
12.4 SETTING OUT BOTTOM COURSE OF SHELL PLATES
In setting out the bottom course of shell plates, allowance shall be made for the contraction of the
vertical joints during welding. While the plates are being plumbed and checked for circularity, and
before they are tack-welded to the bottom, they shall be held in position by metal clamps or other
devices attached to the bottom plates.
12.5 CHECKING OF ALIGNMENT
Before final welding of the bottom course of shell plates begins, a check should be made to ensure
that the alignment of the plates and the width of the gaps between them are correct, and that any
TAKREER
PROJECT SPECIFICATION
FIELD ERECTED WELDED
STEEL STORAGE TANKS
(API 620)
TAKREER
PROJECT No 5578
Agreement no 07-5578-F-1
RUWAIS REFINERY
EXPANSION PROJECT COMPANY Doc. No. 5578-AMD-MF-003
ENG Doc. 25418-1000-3PS-MT00-M0003 Rev.1
ELECTRONIC DOCUMENTS, ONCE PRINTED, ARE NON-CONTROLLED AND MAY BECOME OUTDATED
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inaccuracies after welding will be within the tolerances mentioned below. If the tolerances are
expected to be exceeded, the plates shall be realigned before final welding begins.
Care shall be taken to minimize lack of circularity or distortion between the top and bottom of the
tank shell, whether due to welding or any other cause. The CONTRACTOR/COMPANY reserves
the right to defer acceptance of any tank which shows shell plate buckling until the fault has been
rectified to the satisfaction of CONTRACTOR/COMPANY’S representative. Rectification by
cutting of shell plates is not permitted under any circumstances.
After the first course has been erected and welded, the internal radius, measured horizontally from
the center of the tank to any point on the inside of the tank shell, shall not vary from the nominal
internal radius by more than that specified in API-620 Para 6.5.
12.6 ROOF FRAMING
Before erection of the roof framing begins, the tank shell shall be carefully checked for uneven
settlement, and any misalignment of the top of the shell shall be corrected before the roof members
are positioned.
Temporary supports for the erection of the roof framing shall not be removed until the erection of
the main and secondary framing is complete.
With dome roofs, the temporary center support shall not be removed until radial rafters, purlins and
bracings are erected, completed and welded, and all roof sheets are tack-welded into position. The
positioning of the roof trusses shall be done very accurately to prevent misalignment.
When assembling roof sheets on the framing, excessive unsymmetrical loads shall be avoided and
not more than three roof sheets shall be stacked at any one point.
For dome roofs, the roof sheets shall be assembled symmetrically, working from the center
outwards.
The strength of erection poles used for temporary support of the roof structure shall be checked by
calculation for the maximum load to be carried.
In particular the resistance to buckling shall be checked. The erection VENDOR shall make a
calculation showing strength and safety of the erection poles to be used.
12.7 SHELL TOLERANCES
12.7.1 Verticality of the Tank Shell
After completion, the out-of-plumbness of the top of the shell relative to the bottom of the shell
shall not exceed 1/200 of the total tank height.
12.7.2 Local Deviations
Local deviations and tolerances from the Theoretical shape shall be in accordance with API-620
Para 6.5.4.
TAKREER
PROJECT SPECIFICATION
FIELD ERECTED WELDED
STEEL STORAGE TANKS
(API 620)
TAKREER
PROJECT No 5578
Agreement no 07-5578-F-1
RUWAIS REFINERY
EXPANSION PROJECT COMPANY Doc. No. 5578-AMD-MF-003
ENG Doc. 25418-1000-3PS-MT00-M0003 Rev.1
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Such departures from the design form shall be gradual over the gauge length, sharp changes in
form are not permitted.
12.7.3 Tolerances for Misalignment of Plates at Butt Welded Joints
a. Plates to be joined by butt welding shall be matched accurately and retained in position
during the welding operation. Matching of unequal thickness shall be as per API 620 Para
6.9, 6.13, 6.14 & 6.16.
13 FOUNDATIONS
13.1 CHECKING OF FOUNDATIONS
Before the start of erection, inspect each tank foundation to ensure that it is level and acceptable to
receive Work.
Tank erection and foundation tolerances shall be in accordance with API Standard 620, Para. 6.5.
Tank foundation shall meet requirement of API 620 Appendix – C.
Uneven foundation and settlement can result in the shell assuming an oval shape at the top,
particularly for floating roof tanks causing the floating roof to stick.
An indication a tank is settling unevenly is the appearance of gaps in the circumferential seams,
and departure of the shell from the perpendicular. If these signs appear, no attempt should be made
to close the gap by pulling with the key plates and wedges or cutting of plates.
The tank level should be checked and corrected by leveling of the foundation, if necessary. If the
gap is due to inaccurate fabrication, plate edges should be built up with weld metal, and the joint
welded. The weld built-up area shall receive radiographic testing after the welding is completed.
Pulling the plates to close the gap will cause deformations of the tank shell. To obtain a
perpendicular and circular shell, a level tank foundation is essential.
Tank foundations are usually finished off. Steel plates should be placed temporarily across the
edge of the tank foundation, in order to protect it while the bottom plates are being dragged into
position. Protection of foundation should also be provided even after bottom plates are dragged,
until completion of erection to handover.
13.2 ACCEPTANCE OF FOUNDATIONS
Before erection starts the VENDOR shall check the foundations of the tanks as regards height,
shape and level and will subsequently accept the base and take over responsibility for it.
This also includes the responsibility for its appearance and final shape after completion of the tank
erection, excluding the influence of soil settlement. If soil settlement is observed, the VENDOR
shall inform the CONTRACTOR/COMPANY immediately.
TAKREER
PROJECT SPECIFICATION
FIELD ERECTED WELDED
STEEL STORAGE TANKS
(API 620)
TAKREER
PROJECT No 5578
Agreement no 07-5578-F-1
RUWAIS REFINERY
EXPANSION PROJECT COMPANY Doc. No. 5578-AMD-MF-003
ENG Doc. 25418-1000-3PS-MT00-M0003 Rev.1
ELECTRONIC DOCUMENTS, ONCE PRINTED, ARE NON-CONTROLLED AND MAY BECOME OUTDATED
25418-1000-3PS-MT00-M0003 Page 27 of 37
The tank VENDOR should be made aware of the predicted soil settlements stated in the soil
investigation report.
13.3 CATHODIC PROTECTION OF TANK BOTTOM PLATES
Cathodic protection shall be utilized as a method of arresting corrosion on tank bottom plates in
conjunction with protective coatings.
It is critical that the tank VENDOR or SUBCONTRACTOR design procure and install the
impressed current cathodic protection anodes, reference electrodes, cables etc. During the
construction of the tank foundation and prior to the installation of the tank bottom. Tank bottom
cathodic protection system shall be designed in accordance with 5578-AMD-MY-002.
14 OPERATIONAL FITTINGS FOR VERTICAL TANKS
Unless otherwise specified on PROJECT tank drawings, tanks shall be provided with the standard
range of fittings and accessories as noted in this specification. Optional fittings shall be supplied
only when specified on the PROJECT tank drawings.
14.1 RANGE OF FITTINGS AND ACCESSORIES
14.1.1 Standard Range
VENDOR shall submit descriptive literature on all furnished accessories such as swing lines,
automatic tank gauges (when furnished by tank VENDOR) and rim seal with his quotation.
Unless otherwise specified on requisition, tanks shall be provided with the standard range of
fittings and accessories as listed on individual CONTRACTOR tank drawings/data sheets.
Optional fittings shall be supplied only when specified on the requisition.
For details of standard fittings and accessories, see applicable Standard Drawings.
For very high pumping rates or in other exceptional circumstances, it may be necessary to increase
the numbers or sizes of standard fittings, or to use special fittings or accessories (i.e. to carry out
in-tank blending). In such instances full supporting details should be included when ordering the
tank.
The numbers or sizes of fittings should not be reduced, since adherence to the specified range will
simplify the procurement of fittings, reduce delivery times, facilitate the fabrication erection of
tankage and ensure interchangeability.
Fittings such as breather valves, free vents and dip hatches may be to VENDOR’S designs if these
are accepted for use by the CONTRACTOR/COMPANY.
14.1.2 Breather Valves and Free Vents
The number and sizes of breather valves and free vents required should be specified separately due
to the large variations in pumping rates (per API-2000). The flow capacities of the breather valves
shall be based on data received from the valve Manufacturer.
TAKREER
PROJECT SPECIFICATION
FIELD ERECTED WELDED
STEEL STORAGE TANKS
(API 620)
TAKREER
PROJECT No 5578
Agreement no 07-5578-F-1
RUWAIS REFINERY
EXPANSION PROJECT COMPANY Doc. No. 5578-AMD-MF-003
ENG Doc. 25418-1000-3PS-MT00-M0003 Rev.1
ELECTRONIC DOCUMENTS, ONCE PRINTED, ARE NON-CONTROLLED AND MAY BECOME OUTDATED
25418-1000-3PS-MT00-M0003 Page 28 of 37
The maximum flow through a breather valve, when the pallet is fully open, occurs at a pressure
higher than that at which the valve pallet just commences to open, by an amount dependent on the
design of the valve and the weight of the pallet. The weight shall be adjusted so that the pallet is
fully open when the pressure just equals the pressure rating.
If the operating conditions of a tank are changed it shall be checked that the required venting
capacity does not exceed the available venting capacity of the breather valves or free vents.
14.1.3 Free Vents
All free vents if provided on tanks shall be screened. When deciding on the number of free vents
required, their capacity shall be taken at a pressure 0.0076 kg/cm2(g) and a vacuum of 0.0025
kg/cm2 (g).
14.1.4 Roof Nozzles
The flow characteristics of breather valves and free vents are influenced by the profile and length
of the roof nozzle. A tapered nozzle allows a higher flow through the valve than a straight nozzle.
This effect should be taken into account when calculating capacity ratings.
Wire netting in the openings of free vents and breather valves (i.e. as used to prevent nesting of
birds) shall have openings at least 6 mm square. Fine-mesh screens (i.e. as anti-flash protection)
should not be used because of the danger of blockage, especially under winter conditions.
14.1.5 Required Venting Capacity
The venting capacity required shall be determined in accordance with the rules specified in API
2000. These requirements shall be considered as minimum requirements.
The venting requirements shall include the following conditions:
• Inbreathing resulting from a maximum outflow of product from tank.
• Inbreathing resulting from contraction of vapors caused by a maximum decrease in
atmospheric temperature; see Para. 14.1.6.
• Outbreathing resulting from a maximum inflow of product into the tank and maximum
evaporation caused by such inflow.
• Outbreathing resulting from expansion and evaporation due to a maximum increase in
atmospheric temperature (thermal breathing).
• Outbreathing resulting from fire exposure.
NOTE: In addition to requirements of the current national and industry code (API 620), both
cone and dome shaped fixed roof tanks shall be designed to fail at the roof-to-shell
connection when subjected to an internal explosion. This is to be considered as a
primary item from a safety point of view, and is intended to eliminate further escalation
such as could result from failure mode at the shell-to-bottom connection.
TAKREER
PROJECT SPECIFICATION
FIELD ERECTED WELDED
STEEL STORAGE TANKS
(API 620)
TAKREER
PROJECT No 5578
Agreement no 07-5578-F-1
RUWAIS REFINERY
EXPANSION PROJECT COMPANY Doc. No. 5578-AMD-MF-003
ENG Doc. 25418-1000-3PS-MT00-M0003 Rev.1
ELECTRONIC DOCUMENTS, ONCE PRINTED, ARE NON-CONTROLLED AND MAY BECOME OUTDATED
25418-1000-3PS-MT00-M0003 Page 29 of 37
14.1.6 Thermal Venting
Special attention is required to the influence of a sudden drop in temperature (i.e. due to
rainfall) on the venting requirements of tanks containing warm product and for tanks in
tropical areas. A drop of 20o C or more in 15 minutes may be experienced. Where these
conditions apply the venting capacity shall be increased by at least 20% of the thermal venting
capacity requirements.
14.1.7 Stairways, Walkways, Platforms, Handrails, and Vertical Ladders
Stairways, landing platforms, ladders, and hand railing shall be provided as specified on Project
tank drawings. Stairways for tanks designed for insulated tanks, shall be double stringer type
supported by a minimum number of brackets.
a. Stairways, Walkways and Platforms
Stairways and walkways shall be designed in accordance with PROJECT Standard
Drawings (see Section 3.0).
Insulated tanks shall be provided with an offset stairway with stringers on both sides. The
offset shall be 25mm greater than the finished insulated thickness. Stairways on non-
insulated tanks shall be the two stringer type and stairway treads shall not be welded
directly to the tank shell.
Stairways and walkways shall be made of carbon steel grating. All grating shall be
galvanized serrated welded grating with 32 mm x 5 mm bearing bars at 30 mm centers and
cross bars at 100 mm centers. Grating material shall be in accordance with ASTM A569
and galvanized in accordance with Specification 5578-AMD-MX-002.
The minimum clear walking space on stairways and walkways shall be 600 mm.
The angle of stairways to the horizontal plane shall be 45o.
Stairway treads shall be galvanized serrated welded grating with 32 mm x 5 mm bearing
bars at 30 mm centers and cross bars at 100 mm centers with perforated or chequred plate
standard nosings. Stairs shall have a rise of 200 mm and treads shall have a minimum
width of 200 mm measured at the middle of the tread. A standard non slip nosing shall be
provided on the grating at the head of stairs
Spiral stairways shall be completely supported by the tank shell, and the ends of any
stringers or supports shall terminate clear of the tank foundation. Stair treads shall not be
welded directly to medium high tensile steel shells having a thickness of more than 12.5
mm.
Stairways and walkways shall be capable of supporting a moving concentrated load of
455 kg applied at any point.
TAKREER
PROJECT SPECIFICATION
FIELD ERECTED WELDED
STEEL STORAGE TANKS
(API 620)
TAKREER
PROJECT No 5578
Agreement no 07-5578-F-1
RUWAIS REFINERY
EXPANSION PROJECT COMPANY Doc. No. 5578-AMD-MF-003
ENG Doc. 25418-1000-3PS-MT00-M0003 Rev.1
ELECTRONIC DOCUMENTS, ONCE PRINTED, ARE NON-CONTROLLED AND MAY BECOME OUTDATED
25418-1000-3PS-MT00-M0003 Page 30 of 37
Walkways which extend from one tank to another tank or structure, or to the ground, shall
be supported in such a way as to permit free movement of the structures jointed by the
walkway, relative to each other and to the ground.
Spiral stairways for tanks with insulated shells shall be adapted to suit the type of insulation
used. Stair treads or stringers shall not penetrate the insulation.
b. Handrails
Handrails on tank roofs, stairways and walkways shall be designed in accordance with
PROJECT Standard drawings (see Section 3.0). The following requirements shall apply:
• Handrails shall be constructed from carbon steel tubular type.
• The distance between handrail uprights around the tank perimeter, on walkways, or
along the slope of stairways shall not exceed 2.4 m (96 in.).
• Handrails shall be provided on both sides of walkways and straight stairways, and
also on both sides of circumferential spiral stairways if the distance between the inner
stringer and the tank exceeds 200 mm.
• On all handrails the top rail and all uprights shall be capable of withstanding a load
of 91 kg applied at any point and in any direction at any point on the top rail.
• Safety handrails tubular type shall be provided around the roof of tank.
c. Vertical Ladders
Fixed vertical ladders shall be constructed of carbon steel and shall be completely supported
by the tank shell, with the ends of the runners terminating clear of the tank foundation.
Ladders exceeding 4.0 m in length shall be provided with safety cages (see Section 3.0).
14.1.8 Unless otherwise specified, the following shall be hot dip galvanized and/or painted in accordance
with PROJECT Specifications 5578-AMD-MX-002 and/or 5578-AMD-MX-001. Repair of
galvanizing and painting shall also be in accordance with the above specifications.
a. Spiral stair treads, stringer (if used), and stair railing.
b. Platforms (including supporting members) and handrails.
c. Ladders and cages.
d. Automatic tank gage elbows and pipe.
e. Wherever hot dip galvanizing is specified, either in this specification or on drawings, all
related bolting and detail hardware shall be galvanized.
14.1.9 Shell nozzle connections shall be API Standard 620 regular type unless otherwise specified.
Heating coil or heater nozzles shall be furnished with a 150 mm long internal projection beveled
for field welding whenever coil or heater is furnished by others.
TAKREER
PROJECT SPECIFICATION
FIELD ERECTED WELDED
STEEL STORAGE TANKS
(API 620)
TAKREER
PROJECT No 5578
Agreement no 07-5578-F-1
RUWAIS REFINERY
EXPANSION PROJECT COMPANY Doc. No. 5578-AMD-MF-003
ENG Doc. 25418-1000-3PS-MT00-M0003 Rev.1
ELECTRONIC DOCUMENTS, ONCE PRINTED, ARE NON-CONTROLLED AND MAY BECOME OUTDATED
25418-1000-3PS-MT00-M0003 Page 31 of 37
14.1.10 Grounding clips shall be provided in accordance with PROJECT Specification 5778-
AMD-MF-001.
14.1.11 VENDOR shall supply blind flanges, gaskets, and bolting (for other types of blanking covers as
may be required) necessary for testing. Supply covers for connections specified with service
covers remaining in place following tests. For connections not specified to be supplied with
service covers, the test covers shall be removed after testing.
14.2 DESIGN OF FITTINGS, MOUNTINGS AND ACCESSORIES
14.2.1 General
Tanks shall be provided with fittings and mountings as specified on the requisition. All tank fittings
and mountings shall be in accordance with the applicable standard detail drawings and any
additional requirements specified.
14.2.2 Flange Drilling
The flanges for all mountings up to and including 24 in. (600 mm) nominal pipe size, except shell
and roof manholes shall be made and drilled in accordance with ANSI B16.5. Flanges for nominal
pipe sizes over 24 in. (600 mm) shall be made and drilled in accordance with ASME/ANSI B
16.47, Series B.
14.2.3 Holding-Down Bolts
If holding-down bolts are included in the supply, they shall be fabricated as soon as possible after
approval of the relevant drawing by the company and be dispatched to the delivery point as defined
in the order.
Holding-down bolts are to be hot dip galvanized. The threads of the bolts and nuts shall be oiled at
installation.
14.2.4 Side-Entry Mixers
a. Both static and dynamic moments shall be checked by the tank CONTRACTOR, against the
appropriate design code, as well as static and dynamic stresses at the top edge of the reinforcing
pad. Deflections of the material just outside the mixer entry nozzle and around the reinforcing etc.
shall also be checked.
b. Minimum Clearance Between Propeller(s) and Tank Roof
For fixed roof tanks.
For fixed roof tanks the distance between the highest point of the propeller arc and the fixed roof
shall be not less than 2.5 m.
TAKREER
PROJECT SPECIFICATION
FIELD ERECTED WELDED
STEEL STORAGE TANKS
(API 620)
TAKREER
PROJECT No 5578
Agreement no 07-5578-F-1
RUWAIS REFINERY
EXPANSION PROJECT COMPANY Doc. No. 5578-AMD-MF-003
ENG Doc. 25418-1000-3PS-MT00-M0003 Rev.1
ELECTRONIC DOCUMENTS, ONCE PRINTED, ARE NON-CONTROLLED AND MAY BECOME OUTDATED
25418-1000-3PS-MT00-M0003 Page 32 of 37
c. Side entry mixers shall meet the requirements of specification, 5578-AMD-MV-005
15 WELDING AND FABRICATION
15.1 WELDING
15.1.1 Weld tanks in accordance with Welding Specification 5578-AMD-MW-003. Welding shall not
commence until VENDOR’S welding procedures have been approved by CONTRACTOR.
15.1.2 Locate vertical seams in bottom shell course a minimum of 300 mm (12 inches) away from bottom
annular ring radial weld seams.
15.1.3 Attach structural clips, handrail posts, and other components to the tank by welding with
continuous fillet welds.
15.1.4 Remove temporary erection attachments welded to the interior or exterior of the shell or to the
bottom by arc gouging, and grind weld area smooth.
15.1.5 The interior of tanks to be internally lined or coated must have all edges rounded to a minimum of
3 mm radius. Internal welds must be completely seal welded, ground smooth, and free from
surface porosity, pockets, and high spots. Remove weld spatter.
Additional surface preparation must be performed by VENDOR as specified on tank drawing
and/or as indicated in Lining Specification 5578-AMD-MX-004.
VENDOR shall also be aware that fabrication and layout of the bottom plates may be dependent on
the lining manufacturers requirements.
15.1.6 Butt welded shell seams must be located to avoid openings. If the location of connections or
attachments established by CONTRACTOR does not permit adequate clearance, consult
CONTRACTOR for a decision.
15.2 FABRICATION TOLERANCES
15.2.1 Tank erection and foundation tolerances must be in accordance with API-620 and as indicated in
this specification:
15.2.2 Install tank nozzles (excluding manholes) within the following tolerances:
a. Projection from outside of tank shell to extreme face of flange - plus or minus 5 mm.
b. Elevation or radial location - plus or minus 6 mm.
NOTE 1) Fabrication of tank shall also meet requirement of API 620 Section – 6.
2) Inspection, examination and testing of tank shall also meet requirement of API 620
Section – 7.
15.3 TANK PARTS
15.3.1 Plate Edge Preparation
TAKREER
PROJECT SPECIFICATION
FIELD ERECTED WELDED
STEEL STORAGE TANKS
(API 620)
TAKREER
PROJECT No 5578
Agreement no 07-5578-F-1
RUWAIS REFINERY
EXPANSION PROJECT COMPANY Doc. No. 5578-AMD-MF-003
ENG Doc. 25418-1000-3PS-MT00-M0003 Rev.1
ELECTRONIC DOCUMENTS, ONCE PRINTED, ARE NON-CONTROLLED AND MAY BECOME OUTDATED
25418-1000-3PS-MT00-M0003 Page 33 of 37
a. General
The edges of plates may be sheared, machined, or cut with a machine-operated gas torch.
Shearing shall be limited to plates 10 mm or less in thickness.
When the edges of plates are cut with a torch the resulting surface shall be uniform and smooth
and shall be free from scale and slag accumulations before welding. A remaining fine film of
rust adhering to cut or sheared edges after wire brushing need not be removed before welding.
Curved edges of roof and bottom sketch plates and bottom annular plates shall be cut to shape
in the workshop by mechanized gas cutting or machining.
Plate thickness greater than 25mm shall be preheated prior to flame cutting.
b. Plate Edge Joints for Shell Plates
Recommended plate edge joints for hand welding are as follows:
• Vertical joints
Open-gap square butt joints may be used only for plate thicknesses of 6 mm and full
penetration welds are required.
Single-V butt joints shall not be used for plate thicknesses exceeding 13 mm.
Double-V butt joints shall not be used for plate thicknesses < 8 mm and shall be used
for plate thicknesses over 13 mm.
• Horizontal joints
Open-gap square butt joints may be used only where the thickness of the thinner plate
does not exceed 8 mm and full penetration welds are required.
Single-bevel butt joints may be used for plate thicknesses up to 8 mm and shall be used
where the thickness of the thinner plate exceeds 8 mm but does not exceed 13 mm.
Double-bevel butt joints may be used for plate thicknesses over 6 mm and shall be used
for plate thicknesses exceeding 13 mm.
15.3.2 Plate Tolerances
The profile of all shell plates shall be in accordance with API-Standard 620.
15.3.3 Rolling and Pressing
All shell plates shall be rolled to the correct tank curvature. Shell plates for tanks smaller than
25 m diameter shall have their ends pre-set to the proper curvature.
16 INSPECTION
TAKREER
PROJECT SPECIFICATION
FIELD ERECTED WELDED
STEEL STORAGE TANKS
(API 620)
TAKREER
PROJECT No 5578
Agreement no 07-5578-F-1
RUWAIS REFINERY
EXPANSION PROJECT COMPANY Doc. No. 5578-AMD-MF-003
ENG Doc. 25418-1000-3PS-MT00-M0003 Rev.1
ELECTRONIC DOCUMENTS, ONCE PRINTED, ARE NON-CONTROLLED AND MAY BECOME OUTDATED
25418-1000-3PS-MT00-M0003 Page 34 of 37
16.1 GENERAL
Tanks shall be inspected in accordance with API Standard 620, and as outlined in this
specification.
The COMPANY/CONTRACTOR’S representative shall at all times have free access to all
parts of the site while the work covered by the contract is in progress.
The tank erection VENDOR shall afford the representative all reasonable facilities for ensuring
that the work is being carried out in accordance with the requirements of this specification.
16.2 SURVEYS
Upon completion of welding of the first course shell plates and prior to erection of the second
course, a survey of levelness, circularity, and plumbness shall be performed by the VENDOR.
Measurements shall be taken adjacent to and midpoint between each vertical weld seam. The
locations shall be clearly marked and identified with reference number, and shall be used for
any subsequent surveys as well as the final survey.
During the course of tank erection, additional surveys shall be performed as deemed necessary
by the VENDOR.
A final survey shall be performed by the VENDOR after all roof framing has been installed.
VENDOR shall submit the results to CONTRACTOR immediately after each survey has been
completed.
16.3 SECTIONING
Sectioning is not permitted on tank shell welds. Spot radiography shall be used in lieu of
sectioning.
17 TANK TESTING
Tanks shall be tested in accordance with API Standard 620.
17.1 TANK BOTTOMS
After welding of the bottom plates of storage tank has been completed, all welds shall be tested to
ensure that the tank bottom is free from leaks. This can be done by using a vacuum box, which
enables any leaks in the seams to be positively located by visual examination.
The test shall preferably be made as soon as possible after welding of the bottom, removal of slag,
and wire brushing, but before any surface coating is applied. The bottom plates shall in any case be
tested before water is let into the tank for hydrostatic testing.
The vacuum box is fitted with a glass viewing panel on its top and has an open bottom, around
which a continuous rubber seal and former are secured. The seal forms an airtight joint around the
section of the weld to be tested when the box is pressed against the bottom plates.
A partial vacuum can be created by means of a hand or motor-driven vacuum pump. A vacuum
gauge is incorporated in the box which has two connections: one is the suction tap fitted with a
non-return valve; the other is a vacuum release valve.
TAKREER
PROJECT SPECIFICATION
FIELD ERECTED WELDED
STEEL STORAGE TANKS
(API 620)
TAKREER
PROJECT No 5578
Agreement no 07-5578-F-1
RUWAIS REFINERY
EXPANSION PROJECT COMPANY Doc. No. 5578-AMD-MF-003
ENG Doc. 25418-1000-3PS-MT00-M0003 Rev.1
ELECTRONIC DOCUMENTS, ONCE PRINTED, ARE NON-CONTROLLED AND MAY BECOME OUTDATED
25418-1000-3PS-MT00-M0003 Page 35 of 37
For the detection of leaks, soap suds or some alternative substance shall be applied to all joints.
After jacking-up of a tank for re-leveling, the tank bottom shall again be tested for leaks.
17.2 TANK SHELLS
The shells of fixed roof tanks shall be tested after completion of the roof.
For fixed roof tanks, testing shall be done by filling the tanks with fresh water to the level of the
top leg of the top curb angle, and noting any leaks over a period of at least 24 hours.
For hydro testing of storage tanks, seawater may have to be used. Where seawater is used,
corrosion inhibitors shall be used to limit corrosion and will be subject to agreement with
COMPANY/CONTRACTOR. In addition, the method of hydro testing tanks greater than 90
meters in diameter shall be subject to the agreement of COMPANY/CONTRACTOR at the time of
enquiry.
Any tank showing evidence of leakage from the bottom during test must be emptied immediately.
The source of leakage must be determined and the defect repaired prior to refilling.
Unless otherwise agreed, the CONTRACTOR/COMPANY shall provide, install and remove all
pumps, water and water lines temporarily required for the testing of the tanks. All shell openings
shall be closed with blind flanges by the erection VENDOR.
17.2.1 The hydro test shall be performed using clean water or sea water and held for 48 hours maximum,
and draining shall start immediately after test is completed. If leaving test water in the tank(s) for
longer time periods is proposed, inhibitors and/or temporary impressed current cathodic protection
shall be used and a detailed plan shall be submitted to CONTRACTOR/COMPANY for approval.
Hydro test water shall be potable water with chloride level less than 30ppm, or inhibited sea water.
17.3 TANK ROOFS
Upon completion, the tank roof shall be tested in accordance with API-620 Section – 7. The
influence of sudden barometric changes and possible condensation during the night shall be
considered.
For the detection of leaks, soap suds or some alternative substance shall be applied to all joints.
Alternatively, the roof weld seams may be tested by the vacuum box method.
17.4 REPAIR OF LEAKS
All leaks detected during testing shall be repaired to the satisfaction of CONTRACTOR’S
representative, and on completion the entire tank shall be tight and free from leaks.
In the joints between shell plates or bottom plates, or both, the defective part shall first be cut out
and repaired by welding.
When the tank is filled with water for testing, defects in the shell joints shall be repaired with the
water level at least 0.3 m below the work.
TAKREER
PROJECT SPECIFICATION
FIELD ERECTED WELDED
STEEL STORAGE TANKS
(API 620)
TAKREER
PROJECT No 5578
Agreement no 07-5578-F-1
RUWAIS REFINERY
EXPANSION PROJECT COMPANY Doc. No. 5578-AMD-MF-003
ENG Doc. 25418-1000-3PS-MT00-M0003 Rev.1
ELECTRONIC DOCUMENTS, ONCE PRINTED, ARE NON-CONTROLLED AND MAY BECOME OUTDATED
25418-1000-3PS-MT00-M0003 Page 36 of 37
17.5 RETESTING
After all defects have been repaired the repaired welds shall be retested by the methods previously
described.
If further leaks are discovered when the tank is first filled with product, repairs shall not be made
until the tank has been rendered safe in accordance with Paragraph 17.7.
17.6 INITIAL FILLING
The initial filling of a tank with water, shall be done slowly and a continuous inspection shall be
maintained for the whole of the filling period, especially with a floating roof tank. The filling
procedure shall be established taking soil conditions into account. The filling procedure shall be
described in detail in a specification agreed by the soil mechanics specialist and shall be followed
strictly.
The VENDOR shall perform the hydro test in strict accordance with the procedures outlined in the
“Soils Report.” Due to the soil conditions, differential tank settlement may require jacking of the
tank after hydro test to re-level the tank. Evaluation of the settlement shall be in accordance with
API 620, Section-7. Vendor shall take jacking and leveling into consideration for the tank design.
Uneven settlement of the tank on its foundation shall be reported immediately to
CONTRACTOR/COMPANY’S representative, and filling shall be stopped at any signs of
excessive settlement pending a decision by CONTRACTOR/COMPANY’S representative on the
action to be taken.
In the case of excessive soil settlement, the situation shall be reported to the soil mechanics
specialist and his recommendations considered.
The temperature of the test water shall be not lower than that specified by API 620 for the
conditions concerned.
17.7 SAFETY PRECAUTIONS
The following safety precautions shall be taken:
A product connection shall not be made to any tank for any purpose until the tank is accepted to be
filled with product by CONTRACTOR/COMPANY’S representative.
Once product connections have been made to a tank, welding or other hot work shall not be carried
out until all lines connected to the tank have been disconnected, the open ends of the pipelines
blanked off, and the tank and its vicinity tested and rendered safe to the satisfaction of
CONTRACTOR/ COMPANY’S representative.
Once a tank has contained product, welding or other hot-work is prohibited before, in addition to
the requirements above, the tank has been completely emptied and rendered safe in accordance
with the local safety regulations, and written authority for the work has been issued by
CONTRACTOR/ COMPANY’S representative.
Roof manholes shall be open while filling or emptying a fixed roof tank for test purposes, so that
the tank is not damaged by excessive vacuum or pressure loading.
TAKREER
PROJECT SPECIFICATION
FIELD ERECTED WELDED
STEEL STORAGE TANKS
(API 620)
TAKREER
PROJECT No 5578
Agreement no 07-5578-F-1
RUWAIS REFINERY
EXPANSION PROJECT COMPANY Doc. No. 5578-AMD-MF-003
ENG Doc. 25418-1000-3PS-MT00-M0003 Rev.1
ELECTRONIC DOCUMENTS, ONCE PRINTED, ARE NON-CONTROLLED AND MAY BECOME OUTDATED
25418-1000-3PS-MT00-M0003 Page 37 of 37
18 CLEANING AND PAINTING
18.1 CLEANING
In addition to the general cleaning requirements of API Standard 620, the tank VENDOR shall
thoroughly broom sweep and wash clean the inside of each tank. Tank VENDOR shall also
remove all weld slag, loose scale, oil, dirt, sand, debris, and rubbish. Fresh water to be used for
washing and sea water for hydro testing.
18.2 PAINTING AND/OR LINING
Surface preparation and painting shall be in accordance with Specification 5578-AMD-MX-001,
and/or Lining Specification 5578-AMD-MX-004 unless specifically stated otherwise.
All tank plate surfaces shall be shop primed and painted in accordance with the Painting
specification.
Bottom plates shall be 100% coated on the underside in accordance with Painting Specification
5578-AMD-MX-001.
Tanks that are internally lined shall have attachments added to the roof to support hanging
scaffolding to be used during the lining operation. VENDOR to submit details to
CONTRACTOR/COMPANY for approval.
The requisition or order shall state for each tank the treatment/painting and or lining required for
that specific tank.