Reviewer: Please cast your ballot, trying not to abstain. The previous ballot did not receive the required number of replies.
PIP Merge Task Team
July 3, 2003.
NOTES TO REVIEWER:
AGENDA ITEM 650-524: Merge PIP Tank Specifications into API-650.
PURPOSE: This is a revision to API-650 that incorporates most of the technical content of PIP VEST002 and VESTA003, covering atmospheric tanks. The PIP documents were written to reflect the current requirements in the PIP member company internal specifications that modify and amplify the content of API-650. Merging these specifications will put most tank technical requirements into a single industry standard, allowing owners to void much of their internal standards, and diminish the need for supporting project specifications. The intent is that this draft, when completed, will be approved and published as the 11th Edition of API-650.
ACTION: The task team is resubmitting this draft for formal third PV&T Subcommittee Letter Ballot. Remaining work includes: adding bullets to paragraphs with Purchaser options, updating the list of bulleted paragraphs in Appendix L, and updating the list of NDE-related paragraphs. Agenda items approved in the fall of 2002 have been included.
NOTE: The API-650 file provided to the task team contains some unusual formatting, which the reviewer is asked to ignore for now. Lists and tables are particularly affected. Figures and tables in the current 650 have not been issued to the task team, but are part of this document.
SCHEDULE/CONTACTS: The reviewer is welcome to contact the task team members with any questions or comments. The team members are: Steve Braune, Jim Johnston, George Morovich, and Bruce Roberts. Comments are requested by September 1, 2003, to allow time for task team review prior to the PV&T Meeting in Denver.
To assist the reviewer, shading has been used to identify all changes, except some metrication changes. Black unshaded text has not been revised. The codes are:
______Indicates notes to reviewers, or notes to API Staff for information only. Significant technical changes made by the task team are also in yellow. Some very minor changes are not flagged at all, particularly in Appendix L.
______Indicatesthat new text from PIP has been added, or is cause for deletion of text in some cases. Relevant API text which was revised as a consequence is also flagged in blue.Strikeouts indicate deletions of PIP text not accepted by the task team.
xxxx or xxxx Indicates changes resulting from PV&T agenda items approved for publication since this project started in November 2000. The side bar indicating these revisions is also shown in most cases. DO NOT COMMENT ON THESE PARAGRAPHS. Strikeouts from the agenda items are shown in this color
____ Indicates changes made by the task team due to the previous ballot comments..
WORD’s “Comment Note” feature is used to explain some material[ 1]. Click on the pale yellow.
[API/PIP Merged Tank Specification][BER2]
[Above title is for balloting only; it will be deleted]
Welded Steel Tanks for Oil Storage
API Standard 650
Eleventh Edition, December 2003
Addendum 1, January 2000
Draft
FOREWORD
This standard is based on the accumulated knowledge and experience of purchasers and manufacturers of welded steel oil storage tanks of various sizes and capacities for internal pressures not more than 17.2 kPa (2-1/2 pounds per square inch) gauge. This standard is meant to be a purchase specification to facilitate the manufacture and procurement of storage tanks for the petroleum industry.
If the tanks are purchased in accordance with this standard, the purchaser is required to specify certain basic requirements. The purchaser may want to modify, delete, or amplify sections of this standard, but reference to this standard shall not be made on the nameplates of or on the manufacturer’s certification for tanks that do not fulfill the minimum requirements of this standard or that exceed its limitations. It is strongly recommended that any modifications, deletions, or amplifications be made by supplementing this standard rather than by rewriting or incorporating sections of it into another complete standard.
The design rules given in this standard are minimum requirements. More stringent design rules specified by the purchaser or furnished by the manufacturer are acceptable when mutually agreed upon by the purchaser and the manufacturer. This standard is not to be interpreted as approving, recommending, or endorsing any specific design or as limiting the method of design or construction.
This standard is not intended to cover storage tanks that are to be erected in areas subject to regulations more stringent than the specifications in this standard. When this standard is specified for such tanks, it should be followed insofar as it does not conflict with local requirements. The Purchaser is responsible for specifying any jurisdictional requirements applicable to the design and construction of the tank.
After revisions to this standard have been issued, they may be applied to tanks that are to be completed after the date of issue. The tank nameplate shall state the date of the edition of the standard and any revision to that edition to which the tank has been designed and constructed.
Each edition, revision, or addenda to this API standard may be used beginning with the date of issuance shown on the cover page for that edition, revision, or addenda. Each edition, revision, or addenda to this API standard becomes effective six months after the date of issuance for equipment that is certified as being rerated, reconstructed, relocated, repaired, modified (altered), inspected, and tested per this standard. During the six-month time between the date of issuance of the edition, revision, or addenda and the effective date, the purchaser and manufacturer shall specify to which edition, revision, or addenda the equipment is to be rerated, reconstructed, relocated, repaired, modified (altered), inspected, and tested.
API publications may be used by anyone desiring to do so. Every effort has been made by the Institute to assure the accuracy and reliability of the data contained in them; however, the Institute makes no representation, warranty, or guarantee in connection with this publication and hereby expressly disclaims any liability or responsibility for loss or damage resulting from its use or for the violation of any federal, state, or municipal regulation with which this publication may conflict.
The purchaser shall specify whether tanks supplied to this standard will have SI dimensions and comply with applicable ISO standards, or have U.S. Customary dimensions and comply with applicable U.S. standards. Where conflicts arise between SI and U.S. Customary units, the U.S. Customary units will govern[BER3].
Suggested revisions are invited and should be submitted to the Downstream Segment, American Petroleum Institute, 1220 L Street, N.W., Washington, D.C. 20005.
[Table of Contents is to be updated later by API Staff]
l
1Scope1-1
1.1General1-1
1.2Limitations1-2
1.3Compliance1-2
1.4Referenced Publications1-3
2Materials2-1
2.1General2-1
2.2Plates2-1
2.3Sheets2-5
2.4Structural Shapes2-5
2.5Piping and Forgings2-9
2.6Flanges2-10
2.7Bolting2-10
2.8Welding Electrodes2-10
3Design3-1
3.1Joints3-1
3.2Design Considerations3-4
3.3Special Considerations3-5
3.4Bottom Plates3-5
3.5Annular Bottom Plates3-5
3.6Shell Design3-6
3.7Shell Openings3-10
3.8Shell Attachments and Tank Appurtenances3-33
3.9Top and Intermediate Wind Girders3-34
3.10Roofs3-44
3.11Wind Load on Tanks (Overturning Stability)3-51
4Fabrication4-1
4.1General4-1
4.2Shop Inspection4-1
5Erection5-1
5.1General5-1
5.2Details of Welding5-1
5.3Inspection, Testing, and Repairs5-3
5.4Repairs to Welds5-4
5.5Dimensional Tolerances5-5
6Methods of Inspecting Joints6-1
6.1Radiographic Method6-1
6.2Magnetic Particle Examination6-3
6.3Ultrasonic Examination6-4
6.4Liquid Penetrant Examination6-4
6.5Visual Examination6-4
7Welding Procedure and Welder Qualifications7-1
7.1Definitions7-1
7.2Qualification of Welding Procedures7-1
7.3Qualification of Welders7-2
7.4Identification of Welded Joints7-2
8Marking8-1
8.1Nameplates 8-1
8.2Division of Responsibility8-2
8.3Certification8-2
appendix aOptional Design Basis for Small TanksA-1
appendix bRecommendations For Design And Construction
Of Foundations For Aboveground Oil Storage
TanksB-1
appendix cExternal Floating RoofsC-1
appendix dTechnical InquiriesD-1
appendix eSeismic Design Of Storage TanksE-1
appendix fDesign of Tanks for Small Internal PressuresF-1
appendix gStructurally Supported Aluminum Dome RoofsG-1
appendix hInternal Floating RoofsH-1
appendix iUndertank Leak Detection and Subgrade
ProtectionI-1
appendix jShop-Assembled Storage TanksJ-1
appendix kSample Application of the Variable-Design-Point
Method To Determine Shell-Plate ThicknessK-1
appendix lAPI Standard 650 Storage Tank Data SheetsL-1
appendix mRequirements For Tanks Operating At Elevated
TemperaturesM-1
appendix nUse of New Materials That Are Not IdentifiedN-1
appendix oRecommendations for Under-Bottom
ConnectionsO-1
appendix pAllowable External Loads on Tank Shell
OpeningsP-1
appendix sAustenitic Stainless Steel Storage TanksS-1
appendix tNDE Requirements Summary T-1
Figures
2-1Minimum Permissible Design Metal Temperature for Materials Used
in Tank Shells Without Impact Testing2-2
2-2Isothermal Lines of Lowest One-Day Mean Temperatures2-8
2-3Governing Thickness for Impact Test Determination of Shell Nozzle
and Manhole Materials 2-11
3-1Typical Vertical Shell Joints3-2
3-2Typical Horizontal Shell Joints3-2
3-3ATypical Roof and Bottom Joints3-3
3-3BMethod for Preparing Lap-Welded Bottom Plates Under Tank Shell3-3
3-3CDetail of Double Fillet-Groove Weld for Annular Bottom Plates with a
Nominal Thickness Greater Than 13 mm (1/2 in.)3-4
3-4AShell Manhole3-14
3-4BDetails of Shell Manholes and Nozzles3-15
3-5Shell Nozzles3-16
3-6Minimum Spacing of Welds and Extent of Related Radiographic Examination3-22
3-7Shell Nozzle Flanges3-24
3-8Area Coefficient for Determining Minimum Reinforcement of
Flush-Type Cleanout Fittings3-24
3-9Flush-Type Cleanout Fittings3-27
3-10Flush-Type Cleanout-Fitting Supports3-28
3-11Flush-Type Shell Connection3-30
3-12Rotation of Shell Connection3-32
3-13Roof Manholes3-35
3-14Rectangular Roof Openings with Flanged Covers3-37
3-15Rectangular Roof Openings with Hinged Cover3-38
3-16Flanged Roof Nozzles3-39
3-17Threaded Roof Nozzles3-41
3-18Drawoff Sump3-42
3-19Scaffold Cable Support3-43
3-20Typical Stiffening-Ring Sections for Tank Shells3-45
3-21Stairway Opening Through Stiffening Ring3-47
3-22Minimum Weld Spacing Requirements for Openings in Shells According
to Section 3.7.33-49
6-1Radiographic Requirements for Tank Shells6-2+
8-1Manufacturer’s Nameplate8-1
8-2Manufacturer’s Certification Letter8-2
A-1Flush-Type Bolted Door SheetA-11
A-2Supports for Flush-Type Bolted Door SheetA-13
A-3Raised-Type Bolted Door SheetA-15
B-1Example of Foundation With Concrete RingwallB-3
B-2Example of Foundation With Crushed Stone RingwallB-4
E-1Seismic ZonesE-2
E-2Effective MassesE-5
E-3Centroids of Seismic ForcesE-5
E-4Factor kE-5
E-5Compressive Force bE-6
F-1Appendix F Decision TreeF-2
F-2Permissible Details of Compression RingsF-3
G-1Data Sheet for a Structurally Supported Aluminum Dome Added to an
Existing TankG-2
G-2Typical Roof NozzleG-6
I-1Concrete Ringwall with Undertank Leak Detection at the Tank PerimeterI-1
I-2Crushed Stone Ringwall with Undertank Leak Detection at the Tank PerimeterI-2
I-3Earthen Foundation with Undertank Leak Detection at the Tank PerimeterI-2
I-4Double Steel Bottom with Leak Detection at the Tank PerimeterI-3
I-5Double Steel Bottom with Leak Detection at the Tank PerimeterI-3
I-6Reinforced Concrete Slab with Leak Detection at the PerimeterI-4
I-7Reinforced Concrete Slab with Radial Grooves for Leak DetectionI-4
I-8Typical Drawoff SumpI-5
I-9Center Sump for Downward-Sloped BottomI-5
I-10Typical Leak Detection WellsI-6
I-11Tanks Supported by Grillage MembersI-8
O-1Example of Under-Bottom Connection with Concrete Ringwall FoundationO-2
O-2Example of Under-Bottom Connection with Concrete Ringwall
Foundation and Improved Tank Bottom and Shell SupportO-3
O-3Example of Under-Bottom Connection with Earth-Type FoundationO-4
P-1Nomenclature for Piping Loads and DeformationP-3
P-2AStiffness Coefficient for Radial Load: Reinforcement on ShellP-4
P-2BStiffness Coefficient for Longitudinal Moment: Reinforcement in
Nozzle Neck OnlyP-4
P-2CStiffness Coefficient for Circumferential Moment: Reinforcement on ShellP-5
P-2DStiffness Coefficient for Radial Load: Reinforcement on ShellP-5
P-2EStiffness Coefficient for Longitudinal Moment: Reinforcement on ShellP-6
P-2FStiffness Coefficient for Circumferential Moment: Reinforcement on ShellP-6
P-2GStiffness Coefficient for Radial Load: Reinforcement in Nozzle Neck OnlyP-7
P-2HStiffness Coefficient for Longitudinal Moment: Reinforcement in Nozzle
Neck OnlyP-7
P-2IStiffness Coefficient for Circumferential Moment: Reinforcement in
Nozzle Neck OnlyP-8
P-2JStiffness Coefficient for Radial Load: Reinforcement in Nozzle Neck OnlyP-8
P-2KStiffness Coefficient for Longitudinal Moment: Reinforcement in Nozzle
Neck OnlyP-9
P-2LStiffness Coefficient for Circumferential Moment: Reinforcement in
Nozzle Neck OnlyP-9
P-3AConstruction of Nomogram for b1, b2, c1, c2 BoundaryP-11
P-3BConstruction of Nomogram for b1, c3 BoundaryP-11
P-4AObtaining Coefficients YF and YLP-12
P-4BObtaining Coefficient YCP-13
P-5ADetermination of Allowable Loads from Nomogram: FR and MLP-14
P-5BDetermination of Allowable Loads from Nomogram: FR and MCP-14
P-6Low-Type Nozzle with Reinforcement in Nozzle Neck OnlyP-15
P-7Allowable-Load Nomograms for Sample ProblemP-17
Tables
1-1Status of Appendixes to API Standard 6501-2
2-1Maximum Permissible Alloy Content2-3
2-2Acceptable Grades of Plate Material Produced to National Standards2-4
2-3aMaterial Groups, SI Units2-6
2-3bMaterial Groups, US Customary Units2-7
2-4Minimum Impact Test Requirements for Plates2-9
3-1Annular Bottom-Plate Thicknesses3-6
3-2Permissible Plate Materials and Allowable Stresses3-8
3-3Thickness of Shell Manhole Cover Plate and Bolting Flange3-12
3-4Dimensions for Shell Manhole Neck Thickness3-12
3-5Dimensions for Bolt Circle Diameter Db and Cover Plate Diameter Dc
for Shell Manholes3-13
3-6Dimensions for Shell Nozzles3-18
3-7Dimensions for Shell Nozzles: Pipe, Plate, and Welding Schedules3-19
3-8Dimensions for Shell Nozzle Flanges3-20
3-9Dimensions for Flush-Type Cleanout Fittings3-21
3-10Minimum Thickness of Cover Plate, Bolting Flange, and Bottom
Reinforcing Plate for Flush-Type Cleanout Fittings3-23
3-11Thicknesses and Heights of Shell Reinforcing Plates for Flush-Type
Cleanout Fittings3-26
3-12Dimensions for Flush-Type Shell Connections3-29
3-13Dimensions for Roof Manholes3-36
3-14Dimensions for Flanged Roof Nozzles3-36
3-15Dimensions for Threaded Roof Nozzles3-36
3-16Dimensions for Drawoff Sumps3-40
3-17Requirements for Platforms and Walkways3-41
3-18Requirements for Stairways3-41
3-19Rise, Run, and Angle Relationships for Stairways3-43
3-20Section Moduli of Stiffening-Ring Sections on Tank Shells3-46
3.21Uplift Loads
A-1aTypical Sizes and Corresponding Nominal Capacities for Tanks
with 1800 mm CoursesA-2
A-1bTypical Sizes and Corresponding Nominal Capacities for Tanks
with 72-in. CoursesA-3
A-2aShell-Plate Thicknesses for Typical Sizes of Tanks with
1800 mm CoursesA-4
A-2bShell-Plate Thicknesses for Typical Sizes of Tanks with
72-in. CoursesA-5
A-3aTypical Sizes and Corresponding Nominal Capacities for Tanks
with 2400 mm CoursesA-6
A-3bTypical Sizes and Corresponding Nominal Capacities for Tanks
with 96-in. CoursesA-7
A-4aShell-Plate Thicknesses for Typical Sizes of Tanks with
2400 mm CoursesA-8
A-4bShell-Plate Thicknesses for Typical Sizes of Tanks with
96-in. CoursesA-9
A-5Flush-Type Bolted Door SheetsA-12
A-6Raised-Type Bolted Door SheetsA-14
E-1Seismic Zone Tabulation for Areas Outside the United StatesE-4
E-2Seismic Zone FactorE-4
E-3Site CoefficientsE-6
F-1Design Stresses for Anchors of Tanks With Design Pressures up to
18 kPa (21/2 lbf/in.2) GaugeF-5
G-1Bolts and FastenersG-3
J-1Maximum Roof Depths for Shop-Assembled Dome-Roof TanksJ-2
K-1Shell-Plate Thicknesses Based on the Variable-Design-Point Method Using
2400 mm (96 in.) Courses and an Allowable Stress of 159 MPa
(23,000 lbf/in.2) for the Test ConditionK-9
K-2Shell-Plate Thicknesses Based on the Variable-Design-Point Method
Using 2400 mm (96 in.) Courses and an Allowable Stress of 208 MPa
(30,000 lbf/in.2) for the Test ConditionK-10
K-3Shell-Plate Thicknesses Based on the Variable-Design-Point Method
Using 2400 mm (96 in.) Courses and an Allowable Stress of 236 MPa
(34,300 lbf/in.2) for the Test ConditionK-11
M-1Yield Strength Reduction FactorsM-2
M-2Modulus of Elasticity at the Maximum Operating TemperatureM-4
O-1Dimensions of Under-Bottom ConnectionsO-1
P-1Modulus of Elasticity and Thermal Expansion Coefficient at the Design
TemperatureP-2
S-1aASTM Materials for Stainless Steel Components (SI units)S-1
S-1bASTM Materials for Stainless Steel Components (US Customary units)S-2
S-2Allowable Stresses for Tank ShellsS-5
S-3Allowable Stresses for Plate Ring FlangesS-5
S-4Joint EfficienciesS-5
S-5Yield Strength Values in MPa (psi)S-6
S-6Modulus of Elasticity at the Maximum Operating TemperatureS-6
[Reminder for Reviewers: Changes resulting from the last two ballots are shaded in purple text. ]
[Staff: Capitalize “purchaser” and “manufacturer” throughout this document, except in Section 8.]
Welded Steel Tanks for Oil Storage
1 Scope
1.1. General
1.1.1 This standard coversestablishes minimum constructionrequirements for material, design, fabrication, erection (or setting[BER4]), and testing requirements for vertical, cylindrical, aboveground, closed- and open-top, welded carbon or stainless steel storage tanks in various sizes and capacities for internal pressures approximating atmospheric pressure (internal pressures not exceeding the weight of the roof plates), but a higher internal pressure is permitted when additional requirements are met (see 1.1.13). This standard applies only to tanks whose entire bottom is uniformly supported and to tanks in non-refrigerated service that have a maximum operating temperature of 90°C (200°F) (see 1.1.20).
1.1.2 This standard is designed to provide industry with tanks of adequate safety and reasonable economy for use in the storage of petroleum, petroleum products, and other liquid products commonly handled and stored by the various branches of the industry. This standard does not present or establish a fixed series of allowable tank sizes; instead, it is intended to permit the purchaser to select whatever size tank may best meet his needs. This standard is intended to help purchasers and manufacturers in ordering, fabricating, and erecting tanks; it is not intended to prohibit purchasers and manufacturers from purchasing or fabricating tanks that meet specifications other than those contained in this standard.
Note: A bullet (•) at the beginning of a paragraph indicates that there is an expressed decision or action required of the purchaser. The purchaser’s responsibility is not limited to these decisions or actions alone. When such decisions and actions are taken, they are to be specified in documents such as requisitions, change orders, data sheets, and drawings.
1.1.3 [BER5] Where this standard does not address material requirements for miscellaneous items and appurtenances, the Purchaser and/or the Manufacturer shall supply additional material requirements within a supplement to the Data Sheet.
1.1.3 Systems of Units
1.1.3.1This standard has requirements given in two alternate systems of units. The requirements are similar but not identical. These minor differences are due to issues such as numerical rounding and material supply. When applying the requirements of this standard to a given tank, The manufacturer shall comply either with:
1) all of the requirements in this standard given in SI units, or
2) shall comply with all of the requirements in this standard given in US Customary units. The selection of which set of requirements (SI or UScustomary) shall to apply to a given tank shall be by mutual agreement between the manufacturer and Purchaser and noted on the Data Sheet.
[Reviewers: The following text combines the recent agenda item on this subject with a PIP proposal. Doug Miller has provided input into this as well. …Task Team]
1.1.3 Systems of Units
1.1.3.1This standard has requirements given in two alternate systems of units1. The manufacturer shall comply with either:
1) all of the requirements given in this standard in SI units, or
2) all of the requirements given in this standard in US Customary units.
The selection of which set of requirements (SI or US customary) to apply to a given tank shall be indicated on the Data Sheet.
1.1.3.2The purchaser will specify, using the Data Sheet, Line 1, whether all documents transmitted between the Manufacturer and the Purchaser, for tanks constructed to this standard, shall use SI units or US Customary units.
Footnote 1: The requirements of the two systems are similar but not identical. These minor differences are due to issues such as numerical rounding and material supply.