API 653 Nov 2023 Tank Inspection Standard PDF

Copyrighted material licensed to Buckeye Partners by Techstreet LLC, subscriptions.techstreet.com, downloaded on 2023-11-15 14:28:43 +0000 by Aaron Roth. No further reproduction or distribution is permitted. Tank Inspection, Repair, Alteration, and Reconstruction FIFTH EDITION, NOVEMBER 2014 ADDENDUM 3, NOVEMBER 2023 ADDENDUM 1, APRIL 2018 ADDENDUM 2, MAY 2020 API STANDARD 653 Copyrighted material licensed to Buckeye Partners by Techstreet LLC, subscriptions.techstreet.com, downloaded on 2023-11-15 14:28:43 +0000 by Aaron Roth. No further reproduction or distribution is permitted. Special Notes API publications necessarily address problems of a general nature. With respect to particular circumstances, local, state, and federal laws and regulations should be reviewed. The use of API publications is voluntary. In some cases, third parties or authorities having jurisdiction may choose to incorporate API standards by reference and may mandate compliance. 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See Annex I for additional information. Proposed revisions shall be submitted to the Director, Standards Department, American Petroleum Institute, 200 Massachusetts Avenue, NW, Suite 1100, Washington, DC 20001, [email protected]. iii Copyrighted material licensed to Buckeye Partners by Techstreet LLC, subscriptions.techstreet.com, downloaded on 2023-11-15 14:28:43 +0000 by Aaron Roth. No further reproduction or distribution is permitted. Foreword Nothing contained in any API publication is to be construed as granting any right, by implication or otherwise, for the manufacture, sale, or use of any method, apparatus, or product covered by letters patent. Neither should anything contained in the publication be construed as insuring anyone against liability for infringement of letters patent. The verbal forms used to express the provisions in this document are as follows. Shall: As used in a standard, “shall” denotes a minimum requirement in order to conform to the standard. 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A catalog of API publications and materials is published annually by API, 200 Massachusetts Avenue, NW, Suite 1100, Washington, DC 20001. The American Petroleum Institute maintains this standard under continuous maintenance procedures. These procedures establish a documented program for regular publication of addenda or revisions, including timely and documented consensus action on requests for revisions to any part of the standard. See Annex I for additional information. Suggested revisions are invited and should be submitted to the Standards Department, API, 200 Massachusetts Avenue, NW, Suite 1100, Washington, DC 20001, [email protected]. iiii Copyrighted material licensed to Buckeye Partners by Techstreet LLC, subscriptions.techstreet.com, downloaded on 2023-11-15 14:28:43 +0000 by Aaron Roth. No further reproduction or distribution is permitted. Copyrighted material licensed to Buckeye Partners by Techstreet LLC, subscriptions.techstreet.com, downloaded on 2023-11-15 14:28:43 +0000 by Aaron Roth. No further reproduction or distribution is permitted. Contents Page 1 Scope................................................................................ 1-1 1.1 Introduction........................................................................... 1-1 1.2 Compliance with This Standard........................................................... 1-1 1.3 Jurisdiction........................................................................... 1-2 1.4 Safe Working Practices.................................................................. 1-2 2 Normative References.................................................................. 2-1 3 Terms and Definitions................................................................... 3-1 4 Suitability for Service................................................................... 4-1 4.1 General............................................................................... 4-1 4.2 Tank Roof Evaluation................................................................... 4-1 4.3 Tank Shell Evaluation................................................................... 4-2 4.4 Tank Bottom Evaluation................................................................ 4-15 4.5 Tank Foundation Evaluation............................................................ 4-19 5 Brittle Fracture Considerations........................................................... 5-1 5.1 General............................................................................... 5-1 5.2 Basic Considerations................................................................... 5-1 5.3 Assessment Procedure................................................................. 5-1 6 Inspection............................................................................. 6-1 6.1 General............................................................................... 6-1 6.2 Inspection Frequency Considerations..................................................... 6-1 6.3 Inspections from the Outside of the Tank.................................................. 6-1 6.4 Internal Inspection...................................................................... 6-2 6.5 Alternative to Internal Inspection to Determine Bottom Thickness............................. 6-8 6.6 Preparatory Work for Internal Inspection................................................... 6-8 6.7 Inspection Checklists................................................................... 6-8 6.8 Records.............................................................................. 6-8 6.9 Reports............................................................................... 6-8 6.10 Nondestructive Examination (NDE)....................................................... 6-10 7 Materials.............................................................................. 7-1 7.1 General............................................................................... 7-1 7.2 New Materials.......................................................................... 7-1 7.3 Original Materials for Reconstructed Tanks................................................ 7-1 7.4 Welding Consumables.................................................................. 7-1 8 Design Considerations for Reconstructed Tanks............................................ 8-1 8.1 General............................................................................... 8-1 8.2 New Weld Joints....................................................................... 8-1 8.3 Existing Weld Joints.................................................................... 8-1 8.4 Shell Design.......................................................................... 8-1 8.5 Shell Penetrations...................................................................... 8-1 8.6 Windgirders and Shell Stability........................................................... 8-2 8.7 Roofs................................................................................. 8-2 8.8 Seismic Design........................................................................ 8-2 v Copyrighted material licensed to Buckeye Partners by Techstreet LLC, subscriptions.techstreet.com, downloaded on 2023-11-15 14:28:43 +0000 by Aaron Roth. No further reproduction or distribution is permitted. Contents Page 9 Tank Repair and Alteration............................................................... 9-1 9.1 General............................................................................... 9-1 9.2 Removal and Replacement of Shell Plate Material........................................... 9-1 9.3 Shell Repairs Using Lap-welded Patch Plates............................................... 9-4 9.4 Repairs Using Nonmetallic Materials...................................................... 9-8 9.5 Repair of Defects in Shell Plate Material.................................................... 9-8 9.6 Alteration of Tank Shells to Change Shell Height............................................ 9-9 9.7 Repair of Defective Welds............................................................... 9-9 9.8 Repair of Shell Penetrations............................................................. 9-9 9.9 Addition or Replacement of Shell Penetrations............................................. 9-9 9.10 Alteration of Existing Shell Penetrations...................................................9-11 9.11 Repair of Tank Bottoms................................................................ 9-13 9.12 Repair of Fixed Roofs.................................................................. 9-21 9.13 Repair of Floating Roofs................................................................ 9-22 9.14 Repair or Replacement of Floating Roof Perimeter Seals.................................... 9-22 9.15 Hot Taps............................................................................. 9-23 10 Dismantling and Reconstruction......................................................... 10-1 10.1 General.............................................................................. 10-1 10.2 Cleaning and Gas Freeing.............................................................. 10-1 10.3 Dismantling Methods.................................................................. 10-1 10.4 Reconstruction....................................................................... 10-3 10.5 Dimensional Tolerances................................................................ 10-5 11 Welding..............................................................................11-1 11.1 Welding Qualifications..................................................................11-1 11.2 Identification and Records...............................................................11-1 11.3 Preheat or Controlled Deposition Welding Methods as Alternatives to Post-weld Heat Treatment (PWHT)......................................................................11-1 11.4 Welding Safety.........................................................................11-3 11.5 Friction Stud Welding...................................................................11-3 12 Examination and Testing............................................................... 12-1 12.1 NDE................................................................................. 12-1 12.2 Radiographs.......................................................................... 12-4 12.3 Hydrostatic Testing.................................................................... 12-5 12.4 Leak Tests........................................................................... 12-8 12.5 Settlement Survey During Hydrostatic Testing............................................. 12-9 13 Marking and Recordkeeping............................................................ 13-1 13.1 Nameplates........................................................................... 13-1 13.2 Recordkeeping........................................................................ 13-3 13.3 Certification.......................................................................... 13-3 Annex A (informative) Background on Past Editions of API Welded Storage Tank Standards............ A-1 Annex B (normative) Evaluation of Tank Bottom Settlement........................................ B-1 Annex C (informative) Checklists for Tank Inspection............................................. C-1 vi Copyrighted material licensed to Buckeye Partners by Techstreet LLC, subscriptions.techstreet.com, downloaded on 2023-11-15 14:28:43 +0000 by Aaron Roth. No further reproduction or distribution is permitted. Contents Page Annex D (normative) Authorized Inspector Certification........................................... D-1 Annex E (Intentionally Left Blank)............................................................... E-1 Annex F (normative) NDE Requirements Summary............................................... F-1 Annex G (informative) Qualification of Tank Bottom Examination Procedures and Personnel........... G-1 Annex H (informative) Similar Service Assessment............................................... H-1 Annex I (informative) Inquiries and Suggestions for Change......................................... I-1 Annex J (normative, if specified by the purchaser) Shell Plate Repairs Using Nonmetallic Materials........ J-1 Annex R (informative) Additional References for Tank Inspection Guidance.......................... R-1 Annex S (normative) Austenitic Stainless Steel Storage Tanks..................................... S-1 Annex SC (normative) Stainless and Carbon Steel Mixed Materials Storage Tanks................... SC-1 Annex X (normative) Duplex Stainless Steel Storage Tanks........................................ X-1 Annex Y (informative) Bibliography............................................................. Y-1 Figures 4.1 Inspection of Corrosion Areas.......................................................... 4-4 4.2 Pit Measurement...................................................................... 4-5 5.1 Brittle Fracture Considerations......................................................... 5-2 5.2 Exemption Curve for Tanks Constructed from Carbon Steel of Unknown Material Specification... 5-3 9.1 Acceptable Details for Replacement of Shell Plate Material.................................. 9-2 9.2 Details for Door Sheets in Riveted Seam Tank............................................. 9-4 9.3 Details for Door Sheets in Lap-welded Seam Tank......................................... 9-5 9.4 Details for Door Sheets in Butt-welded Shell Seam Tank—No Vertical Seam Offset.............. 9-5 9.5 Details for Door Sheets in Butt-welded Shell Seam Tank—Vertical Seam Offset................. 9-6 9.6 Lapped Patch Repair Plates at the External Shell-to-bottom Joint............................ 9-7 9.7 Typical Details for Addition of Reinforcing Plate to Existing Shell Penetration................. 9-10 9.8 Typical Details for Addition of “Tombstone” Shape Reinforcing Plate to Existing Shell Penetration......................................................................... 9-10 9.9 Method for Raising Shell Nozzles....................................................... 9-12 9.10 Details for Installing a New Bottom Through an Existing Tapered Tombstone................. 9-13 9.11 Details for Installing a New Bottom Through an Existing Tombstone Reinforcing Plate with a Tapered Shell....................................................................... 9-14 9.12 Details for Installing a New Bottom Through an Existing Tombstone Reinforcing Plate......... 9-15 9.13a Typical Welded-on Patch Plates on Tank Bottom Plates, in SI Units.......................... 9-16 9.13b Typical Welded-on Patch Plates on Tank Bottom Plates, in USC Units........................ 9-17 9.14 Hot Tap for Tanks.................................................................... 9-25 10.1 Tank Shell and Bottom Cut Locations................................................... 10-2 13.1 Nameplate.......................................................................... 13-1 13.2 Certification Forms................................................................... 13-4 B.1 Measurements of Shell Settlement (External).............................................. B-2 B.2 Measurements of Bottom Settlement (Internal) Tank Out-of-service.......................... B-2 vii Copyrighted material licensed to Buckeye Partners by Techstreet LLC, subscriptions.techstreet.com, downloaded on 2023-11-15 14:28:43 +0000 by Aaron Roth. No further reproduction or distribution is permitted. Page B.3 Graphical Representation of Tank Shell Settlement per B.2.2.4............................... B-3 B.4 Graphical Representation of Shell Settlement per B.2.2.5 (Tilt Plan Not Described by an Optimal Cosine Curve)........................................................................ B-6 B.5 Graphical Representation of Shell Settlement per B.2.2.5 (Tilt Plane Described by an Optimal Cosine Curve)........................................................................ B-6 B.6 Edge Settlement...................................................................... B-7 B.7 Correction for Measured Edge Settlement................................................ B-8 B.8 Bottom Settlement Near Shell........................................................... B-9 B.9 Localized Bottom Depressions or Bulges Remote from Shell............................... B-10 B.10a Localized Tank Bottom Settlement Limits for Single Pass Welds, in SI Units.................. B-13 B.10b Localized Tank Bottom Settlement Limits for Single Pass Welds, in USC Units................ B-14 B.11a Maximum Allowable Edge Settlement for Areas with Bottom Lap Welds Approximately Parallel to the Shell, in SI Units........................................... B-15 B.11b Maximum Allowable Edge Settlement for Areas with Bottom Lap Welds Approximately Parallel to the Shell, in USC Units......................................... B-16 B.12a Maximum Allowable Edge Settlement for Areas with Bottom Lap Welds Approximately Perpendicular to the Shell, in SI Units...................................... B-17 B.12b Maximum Allowable Edge Settlement for Areas with Bottom Lap Welds Approximately Perpendicular to the Shell, in USC Units................................... B-18 B.13 Edge Settlement with a Lap Weld at an Arbitrary Angle to the Shell.......................... B-18 H.1 Steps in Conducting Similar Service Assessment.......................................... H-6 H.2 Example Corrosion Rate Curves for Bottom of Storage Tank................................ H-7 H.3 Example Corrosion Rate Curves for Top Course of Storage Tank............................. H-8 Similar Service Assessment—Datasheet................................................. H-9 Tables 4.1a Maximum Allowable Shell Stresses, in SI Units............................................ 4-7 4.1b Maximum Allowable Shell Stresses, in USC Units......................................... 4-8 4.2a Joint Efficiencies for Welded Joints, in SI Units.......................................... 4-10 4.2b Joint Efficiencies for Welded Joints, in USC Units........................................ 4-10 4.3 Joint Efficiencies for Riveted Joints.................................................... 4-13 4.4a Bottom Plate Minimum Thickness, in SI Units............................................ 4-18 4.4b Bottom PLate Minimum Thickness, in USC Units......................................... 4-18 4.5a Annular Bottom Plate Thicknesses (Product Specific Gravity < 1.0), in SI Units............... 4-20 4.5b Annular Bottom Plate Thicknesses (Product Specific Gravity < 1.0), in USC Units............. 4-20 6.1 Tank Safeguard...................................................................... 6-4 9.1a Hot Tap Connection Sizes and Shell Plate Thicknesses, in SI Units......................... 9-23 9.1b Hot Tap Connection Sizes and Shell Plate Thicknesses, in USC Units....................... 9-23 10.1a Maximum Thicknesses on New Welds, in SI Units........................................ 10-3 10.1b Maximum Thicknesses on New Welds, in USC Units...................................... 10-3 10.2a Radii Tolerances, in SI Units........................................................... 10-5 10.2b Radii Tolerances, in USC Units........................................................ 10-5 viii Copyrighted material licensed to Buckeye Partners by Techstreet LLC, subscriptions.techstreet.com, downloaded on 2023-11-15 14:28:43 +0000 by Aaron Roth. No further reproduction or distribution is permitted. Page 11.1 Welding Methods as Alternatives to Post-weld Heat Treatment (PWHT) Qualification Thicknesses for Test Plates and Repair Grooves..........................................11-2 A.1 Editions of API Standard 650 and its Precursor, API Standard 12C........................... A-1 C.1 Tank In-service Inspection Checklist..................................................... C-2 C.2 Tank Out-of-service Inspection Checklist................................................. C-8 F.1 NDE Requirements Summary........................................................... F-1 G.1a Underside Pits, in SI Units............................................................. G-4 G.1b Underside Pits, in USC Units........................................................... G-4 G.2a Product-side Pits, in SI Units........................................................... G-5 G.2b Product-side Pits, in USC Units......................................................... G-5 G.3a Flaws Required to Qualify a Procedure or Operator, in SI Units.............................. G-6 G.3b Flaws Required to Qualify a Procedure or Operator, in USC Units............................ G-6 G.4a Flaw Depth to Qualify a Procedure or Examiner, in SI Units................................. G-6 G.4b Flaw Depth to Qualify a Procedure or Examiner, in USC Units............................... G-6 G.5a Suggested Essential Variables for Qualification Tests, in SI Units............................ G-7 G.5b Suggested Essential Variables for Qualification Tests, in USC Units.......................... G-8 H.1 Similar Service Product Classification................................................... H-5 J.1 API Requirements in Addition to ASME PCC-2............................................ J-2 ix Copyrighted material licensed to Buckeye Partners by Techstreet LLC, subscriptions.techstreet.com, downloaded on 2023-11-15 14:28:43 +0000 by Aaron Roth. No further reproduction or distribution is permitted. Copyrighted material licensed to Buckeye Partners by Techstreet LLC, subscriptions.techstreet.com, downloaded on 2023-11-15 14:28:43 +0000 by Aaron Roth. No further reproduction or distribution is permitted. Tank Inspection, Repair, Alteration, and Reconstruction SECTION 1—SCOPE 1.1 Introduction 1.1.1 This standard covers steel storage tanks built to API 650 and its predecessor API 12C. It provides minimum requirements for maintaining the integrity of such tanks after they have been placed in service and addresses inspection, repair, alteration, relocation, and reconstruction. 1.1.2 The scope is limited to the tank foundation, bottom, shell, structure, roof, attached appurtenances, and nozzles to the face of the first flange, first threaded joint, or first welding-end connection. Many of the design, welding, examination, and material requirements of API 650 can be applied in the maintenance inspection, rating, repair, and alteration of in-service tanks. In the case of apparent conflicts between the requirements of this standard and API 650 or its predecessor API 12C, this standard shall govern for tanks that have been placed in service. 1.1.3 This standard has requirements given in two alternate systems of units. Any repairs shall comply with the original construction units, i.e. either: a) all of the requirements given in this standard in metric (SI) units; or b) all of the requirements given in this standard in U.S. customary (USC) units. 1.1.4 This standard employs the principles of API 650; however, storage tank owner/operators, based on consideration of specific construction and operating details, may apply this standard to any steel tank constructed in accordance with a tank specification. 1.1.5 This standard is intended for use by organizations that maintain or have access to engineering and inspection personnel technically trained and experienced in tank design, fabrication, repair, construction, and inspection. 1.1.6 This standard does not contain rules or guidelines to cover all the varied conditions which may occur in an existing tank. When design and construction details are not given, and are not available in the as-built standard, details that will provide a level of integrity equal to the level provided by the current edition of API 650 must be used. 1.1.7 This standard recognizes fitness-for-service assessment concepts for evaluating in-service degradation of pressure containing components. API 579-1/ASME FFS-1, Fitness-For-Service, provides detailed assessment procedures or acceptance criteria for specific types of degradation referenced in this standard. When this standard does not provide specific evaluation procedures or acceptance criteria for a specific type of degradation or when this standard explicitly allows the use of fitness-for-service criteria, API 579-1/ASME FFS-1 may be used to evaluate the various types of degradation or test requirements addressed in this standard. 1.2 Compliance with This Standard The owner/operator has ultimate responsibility for complying with the provisions of this standard. The application of this standard is restricted to organizations that employ or have access to an authorized inspection agency as defined in 3.3. Should a party other than the owner/operator be assigned certain tasks, such as relocating and reconstructing a tank, the limits of responsibility for each party shall be defined by the owner/operator prior to commencing work. 1-1 Copyrighted material licensed to Buckeye Partners by Techstreet LLC, subscriptions.techstreet.com, downloaded on 2023-11-15 14:28:43 +0000 by Aaron Roth. No further reproduction or distribution is permitted. 1-2 API STANDARD 653 1.3 Jurisdiction If any provision of this standard presents a direct or implied conflict with any statutory regulation, the regulation shall govern. However, if the requirements of this standard are more stringent than the requirements of the regulation, then the requirements of this standard shall govern. 1.4 Safe Working Practices An assessment shall be made of the potential hazards to which personnel may be exposed when conducting internal tank inspections, making repairs, or dismantling tanks. Procedures shall be developed according to the guidelines given in API Standard 2015 and API 2217A that will include safeguard for personnel health and safety, prevention of accidental fires and explosions, and the prevention of property damage. Conformance to permit procedures is an essential safe work practice for protection of personnel and property. Where welding and hot work are involved, API 2009 states “Except in areas specifically designated as safe for hot work, a hot work permit shall be obtained before starting any work that can involve a source of ignition.” See also API Standard 2015. Special procedures may need to be developed for certain activities described in this standard that are not fully cov- ered by the referenced API publications; e.g. safety precautions for personnel accessing floating roof tanks that are in service, or gas freeing the bottom side of a tank. Appendix B of API 2009 provides brief information on inerting tanks. Use of inerting as a safety precaution should address personnel hazards introduced when using inert gas in the work- place and implementation should be done in consultation with specialists that are familiar with such processes. Finally, procedures must comply with any federal or state safety regulations pertaining to “confined spaces” or any other relevant provisions. Copyrighted material licensed to Buckeye Partners by Techstreet LLC, subscriptions.techstreet.com, downloaded on 2023-11-15 14:28:43 +0000 by Aaron Roth. No further reproduction or distribution is permitted. SECTION 2—NORMATIVE REFERENCES The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. API Recommended Practice 579-1/ASME FFS-1, Fitness-For-Service API Recommended Practice 580, Risk Based Inspection API Standard 620, Design and Construction of Large, Welded, Low-pressure Storage Tanks API Standard 650, Welded Tanks for Oil Storage API Recommended Practice 651, Cathodic Protection of Aboveground Storage Tanks API Recommended Practice 652, Lining of Aboveground Petroleum Storage Tank Bottoms API Standard 2000, Venting Atmospheric and Low-pressure Storage Tanks: Nonrefrigerated and Refrigerated API Recommended Practice 2003, Protection Against Ignitions Arising Out of Static, Lightning, and Stray Currents API Recommended Practice 2009, Safe Welding, Cutting, and Hot Work Practices in the Petroleum and Petrochemical Industries API Standard 2015, Requirements for Safe Entry and Cleaning of Petroleum Storage Tanks API Recommended Practice 2201, Safe Hot Tapping Practices in the Petroleum and Petrochemical Industries API Recommended Practice 2207, Preparing Tank Bottoms for Hot Work API Standard 2217A, Guidelines for Safe Work in Inert Confined Spaces in the Petroleum and Petrochemical Industries ASME Boiler and Pressure Vessel Code (BPVC) 1, Section V: Nondestructive Examination ASME BPVC, Section VIII: Pressure Vessels; Division 2: Alternative Rules ASME BPVC, Section IX: Welding and Brazing Qualifications ASNT SNT-TC-1A 2, Personnel Qualification and Certification in Nondestructive Testing ASTM A6 3, Standard Specification for General Requirements for Rolled Structural Steel Bars, Plates, Shapes, and Sheet Piling ASTM A20, Standard Specification for General Requirements for Steel Plates for Pressure Vessels ASTM A36, Standard Specification for Carbon Structural Steel 1 ASME International, 3 Park Avenue, New York, New York 10016-5990, www.asme.org. 2 American Society for Nondestructive Testing, 1711 Arlingate Lane, Columbus, Ohio, 43228-0518, www.asnt.org. 3 ASTM International, 100 Barr Harbor Drive, West Conshohocken, Pennsylvania 19428-2959, www.astm.org. 2-1 Copyrighted material licensed to Buckeye Partners by Techstreet LLC, subscriptions.techstreet.com, downloaded on 2023-11-15 14:28:43 +0000 by Aaron Roth. No further reproduction or distribution is permitted. 2-2 API STANDARD 653 ASTM A370, Standard Test Methods and Definitions for Mechanical Testing of Steel Products ASTM A992, Standard Specification for Structural Steel Shapes AWS D1.1 4, Structural Welding Code—Steel AWS D1.6, Structural Welding Code—Stainless Steel 4 American Welding Society, 550 N.W. LeJeune Road, Miami, Florida 33135, www.aws.org. Copyrighted material licensed to Buckeye Partners by Techstreet LLC, subscriptions.techstreet.com, downloaded on 2023-11-15 14:28:43 +0000 by Aaron Roth. No further reproduction or distribution is permitted. SECTION 3—TERMS AND DEFINITIONS For the purposes of this standard, the following definitions apply. 3.1 alteration Any work on a tank that changes its physical dimensions or configuration. 3.2 as-built standard The standard (such as API standard or UL 6 standard) used for the construction of the tank component in question. If this standard is not known, the as-built standard is the standard that was in effect at the date of the installation of the component. If the date of the installation of the component is unknown, then the current applicable standard shall be considered to be the as-built standard. See Annex A for a list of API welded storage tank standards. The standard used for repairs or alterations made after original construction is the as-built standard only for those repairs or alterations, so there may be more than one as-built standard for a tank. 3.3 authorized inspection agency One of the following organizations that employ an aboveground storage tank inspector certified by API. a) The inspection organization of the jurisdiction in which the aboveground storage tank is operated. b) The inspection organization of an insurance company which is licensed or registered to and does write aboveground storage tank insurance. c) An owner/operator of one or more aboveground storage tank(s) who maintains an inspection organization for activities relating only to his/her equipment and not for aboveground storage tanks intended for sale or resale. d) An independent organization or individual under contract to and under the direction of an owner/operator and recognized or otherwise not prohibited by the jurisdiction in which the aboveground storage tank is operated. The owner/operator’s inspection program shall provide the controls necessary for use by authorized inspectors contracted to inspect aboveground storage tanks. 3.4 authorized inspector An employee of an authorized inspection agency who is qualified and certified to perform inspections under this inspection standard. Whenever the term inspector is used in API 653, it refers to an authorized API Standard 653 inspector. 3.5 breakover point The area on a tank bottom where settlement begins. 3.6 candidate tank The tank(s) for which corrosion rates are not known. 3.7 change in service A change from previous operating conditions involving different properties of the stored product such as specific gravity or corrosivity and/or different service conditions of temperature and/or pressure. 6 Underwriters Laboratories, 333 Pfingsten Road, Northbrook, Illinois, 60062-2096, www.ul.com. 3-1 Copyrighted material licensed to Buckeye Partners by Techstreet LLC, subscriptions.techstreet.com, downloaded on 2023-11-15 14:28:43 +0000 by Aaron Roth. No further reproduction or distribution is permitted. 3-2 API STANDARD 653 3.8 control tank The tank(s) for which corrosion rates and service history are known and documented. 3.9 corrosion allowance Any additional material thickness available to allow metal loss during the service life of the tank component. It may also represent additional thickness included in the original component design or specified by the purchaser to be added to the thickness for new components in the repair and reconstruction of tanks. 3.10 corrosion rate The total metal loss divided by the period of time over which the metal loss occurred. 3.11 critical zone The portion of the tank bottom or annular plate within 75 mm (3 in.) of the inside edge of the shell, measured radially inward. 3.12 current applicable standard The current edition of the standard (such as API standard or UL standard) that applies if the tank were built today. 3.13 door sheet A plate (or plates) cut from an existing tank shell to create a temporary access opening. After planned work is completed, the door sheet(s) shall be reinstalled or replaced. 3.14 examiner A person who assists the inspector by performing specific nondestructive examination (NDE) on aboveground storage tanks and evaluates to the applicable acceptance criteria, but does not interpret the results of those examinations in accordance with API 653, unless specifically trained and authorized to do so by the owner/operator. 3.15 external inspection A formal visual inspection, conducted or supervised by an authorized inspector, to assess all aspects of the tank as possible without suspending operations or requiring tank shutdown (see 6.3.2). 3.16 fitness-for-service assessment A methodology whereby flaws contained within a structure are assessed in order to determine the adequacy of the flawed structure for continued service without imminent failure. 3.17 hot tap Identifies a procedure for installing a nozzle in the shell of a tank that is in service. 3.18 hydrotest A test performed with water, in which static fluid head is used to produce test loads. Copyrighted material licensed to Buckeye Partners by Techstreet LLC, subscriptions.techstreet.com, downloaded on 2023-11-15 14:28:43 +0000 by Aaron Roth. No further reproduction or distribution is permitted. TANK INSPECTION, REPAIR, ALTERATION, AND RECONSTRUCTION 3-3 3.19 insert plate A steel plate that replaces part of a shell plate with a nominal thickness that is equivalent to, or no more than, 3 mm (1/8 in.) greater than the nominal thickness of the adjoining material. When an insert plate is equal to the full height of a shell ring, it is considered to be a shell plate. 3.20 inspection activities Any activity relating to the performance of inspection of aboveground storage tanks while employed by or under contract with an authorized inspection agency. 3.21 inspector A shortened title for an authorized tank inspector qualified and certified in accordance with this standard. 3.22 internal inspection A formal, complete inspection, as supervised by an authorized inspector, of all accessible internal tank surfaces (see 6.4.1). 3.23 internal inspection deferral An approved and documented postponement on the internal inspection due date of an in-service tank based on the procedures of 6.4.3. 3.24 internal inspection due date The date whereby a tank is scheduled to 1) be emptied of liquid and removed from service for internal inspection or 2) complete an on-stream internal inspection. The date is based on 6.4.2. 3.25 major alteration/or major repair An alteration or repair that includes any of the following: a) installing a shell penetration larger than DN 300 mm (NPS 12) beneath the design liquid level; b) installing a bottom penetration within 300 mm (12 in.) of the shell; c) removing and replacing or adding a shell plate beneath the design liquid level where the longest dimension of the replacement plate exceeds 300 mm (12 in.); d) removing or replacing annular plate ring material where the longest dimension of the replacement plate exceeds 300 mm (12 in.); e) complete or partial (more than one-half of the weld thickness) removal and replacement of more than 300 mm (12 in.) of vertical weld joining shell plates or radial weld joining the annular plate ring; f) a nonmetallic repair that contributes more than one-half the strength of the shell in an area more than 300 mm (12 in.) high; g) installing a new bottom; NOTE Installation of a portion of a new bottom as described in 12.3.4.3 is not defined as a major repair. Copyrighted material licensed to Buckeye Partners by Techstreet LLC, subscriptions.techstreet.com, downloaded on 2023-11-15 14:28:43 +0000 by Aaron Roth. No further reproduction or distribution is permitted. 3-4 API STANDARD 653 h) removing and replacing part of the weld attaching the shell to the bottom, or to the annular plate ring, in excess of the amounts listed in 12.3.3.5.1 a); i) jacking a tank shell. 3.26 nominal thickness The ordered thickness of the material. This thickness includes any corrosion allowance. If the ordered thickness is unknown, the nominal thickness should be determined based on existing plate measured thickness and the judgment of a storage tank engineer. 3.27 owner/operator The legal entity having control of and/or responsibility for the operation and maintenance of an existing storage tank. 3.28 product-side The side of the tank that is in contact with the stored liquid product. 3.29 recognized toughness A condition that exists when the material of a component is deemed acceptable for use by the provisions of any of the following sections of this standard: a) Section 5.3.2 (based on edition of standard of tank’s original construction, or by coupon testing); b) Section 5.3.5 (based on thickness); c) Section 5.3.6 (based on lowest design metal temperature); d) Section 5.3.8 (based on exemption curves). 3.30 reconstruction Any work necessary to reassemble a tank that has been dismantled and relocated to a new site. 3.31 reconstruction organization The organization having assigned responsibility by the owner/operator to design and/or reconstruct a tank. 3.32 repair Work necessary to maintain or restore a tank to a condition suitable for safe operation. Repairs include both major repairs (see 3.25) and repairs that are not major repairs. Examples of repairs include: a) removal and replacement of material (such as roof, shell, or bottom material, including weld metal) to maintain tank integrity; b) re-leveling and/or jacking of a tank shell, bottom, or roof; c) adding or replacing reinforcing plates (or portions thereof) to existing shell penetrations; d) repair of flaws, such as tears or gouges, by grinding and/or gouging followed by welding. 3.33 repair organization An organization that meets any of the following: Copyrighted material licensed to Buckeye Partners by Techstreet LLC, subscriptions.techstreet.com, downloaded on 2023-11-15 14:28:43 +0000 by Aaron Roth. No further reproduction or distribution is permitted. TANK INSPECTION, REPAIR, ALTERATION, AND RECONSTRUCTION 3-5 a) an owner/operator of aboveground storage tanks who repairs or alters his/her own equipment in accordance with this standard; b) a contractor whose qualifications are acceptable to the owner/operator of aboveground storage tanks and who makes repairs or alterations in accordance with this standard; c) one who is authorized by, acceptable to, or otherwise not prohibited by the jurisdiction, and who makes repairs in accordance with this standard. 3.34 similar service assessment The process by which corrosion rates and inspection intervals are established for a candidate tank using corrosion rates and service history from a control tank for the purpose of establishing the next inspection date. 3.35 soil-side The side of the tank bottom that is in contact with the ground. 3.36 storage tank engineer One or more persons or organizations acceptable to the owner/operator who are knowledgeable and experienced in the engineering disciplines associated with evaluating mechanical and material characteristics that affect the integrity and reliability of aboveground storage tanks. The storage tank engineer, by consulting with appropriate specialists, should be regarded as a composite of all entities needed to properly assess the technical requirements. 3.37 structural discontinuity An abrupt change in shape or cross-section that affects stress or strain distribution through the entire wall thickness. 3.38 thickened insert plate A steel plate that replaces part of a shell plate with a nominal thickness that is greater than the nominal thickness of the adjoining material by more than 3 mm (1/8 in.). 3.39 unknown toughness A condition that exists when it cannot be demonstrated that the material of a component satisfies the definition of recognized toughness. Copyrighted material licensed to Buckeye Partners by Techstreet LLC, subscriptions.techstreet.com, downloaded on 2023-11-15 14:28:43 +0000 by Aaron Roth. No further reproduction or distribution is permitted. Copyrighted material licensed to Buckeye Partners by Techstreet LLC, subscriptions.techstreet.com, downloaded on 2023-11-15 14:28:43 +0000 by Aaron Roth. No further reproduction or distribution is permitted. SECTION 4—SUITABILITY FOR SERVICE 4.1 General 4.1.1 When the results of a tank inspection show that a change has occurred from the original physical condition of that tank, an evaluation shall be made to determine its suitability for continued use. 4.1.2 This section provides an evaluation of the suitability of an existing tank for continued service, or for a change of service, or when making decisions involving repairs, alterations, dismantling, relocating, or reconstructing an existing tank. 4.1.3 The following list of factors for consideration is not all-inclusive for all situations, nor is it intended to be a substitute for the engineering analysis and judgment required for each situation: a) internal corrosion due to the product stored or water bottoms; b) external corrosion due to environmental exposure; c) stress levels and allowable stress levels; d) properties of the stored product such as specific gravity, temperature, and corrosivity; e) metal design temperatures at the service location of the tank; f) external roof live load, wind, and seismic loadings; g) tank foundation, soil, and settlement conditions; h) chemical analysis and mechanical properties of the materials of construction; i) distortions of the existing tank; j) operating conditions such as filling/emptying rates and frequency. 4.1.4 API RP 571 identifies damage mechanisms in refining equipment and may be consulted for further information. 4.2 Tank Roof Evaluation 4.2.1 General 4.2.1.1 The structural integrity of the roof and roof support system shall be verified. 4.2.1.2 Roof plates corroded to an average thickness of less than 2.2 mm in any 250 mm x 250 mm (0.09 in. in any 100 in.2) area or roof plates with any holes through the roof plate shall be repaired or replaced. 4.2.2 Fixed Roofs 4.2.2.1 Roof support members (rafters, girders, columns, and bases) shall be inspected for soundness by a method acceptable to the responsible inspector. Distorted (such as out-of-plumb columns), corroded, and damaged members shall be evaluated and repaired or replaced if necessary. Particular attention must be given to the possibility of severe internal corrosion of pipe columns (corrosion may not be evidenced by external visual inspection). 4-1 Copyrighted material licensed to Buckeye Partners by Techstreet LLC, subscriptions.techstreet.com, downloaded on 2023-11-15 14:28:43 +0000 by Aaron Roth. No further reproduction or distribution is permitted. 4-2 API STANDARD 653 4.2.2.2 When a frangible roof-to-shell joint is required, evaluate for items impacting compliance with requirements under API 650, Section 5.10.2.6. Examples of some items to evaluate include tank bottom-to-shell joint corrosion or tank roof-to-shell joint modification (such as reinforcement of the joint, attachment of handrail, or other frangible joint area change). 4.2.3 Floating Roofs 4.2.3.1 Areas of roof plates and pontoons exhibiting cracks or punctures shall be repaired or the affected sections replaced. Holes through roof plates shall be repaired or replaced. 4.2.3.2 Areas that are pitted shall be evaluated to determine the likelihood of through-pitting occurring prior to the next scheduled internal inspection. If so, the affected areas shall be repaired or replaced. 4.2.3.3 Roof support systems, perimeter seal systems, appurtenances such as a roof rolling ladder, anti-rotation devices, water drain systems, and venting systems shall be evaluated for needed repairs or replacements. 4.2.3.4 Guidance for the evaluation of existing floating roofs shall be based on the criteria of API 650, Annex C, for external floating roofs, and Annex H for internal floating roofs. However, upgrading to meet this standard is not mandatory. 4.2.4 Change of Service 4.2.4.1 Internal Pressure All requirements of the current applicable standard (e.g. API 650, Annex F) shall be considered in the evaluation and subsequent alterations to the tank roof and roof-to-shell junction. 4.2.4.2 External Pressure As applicable, the roof support structure (if any), and the roof-to-shell junction shall be evaluated for the effects of a design partial vacuum. The criteria outlined in API 650, Annex V shall be used. 4.2.4.3 Operation at Elevated Temperature All requirements of API 650, Annex M, shall be considered before changing the service of a tank to operation at temperatures above 93 °C (200 °F). 4.2.4.4 Operation at Lower Temperature Than Original Design If the operating temperature is changed to a lower temperature than the original design, the requirements of the current applicable standard for the lower temperature shall be met. 4.2.4.5 Normal and Emergency Venting 4.2.4.5.1 Effects of change in operating conditions (including product service and pumping rates) on normal and emergency venting shall be considered. 4.2.4.5.2 Vents shall be inspected for proper operation and screens shall be verified to be clear of obstruction. 4.3 Tank Shell Evaluation 4.3.1 General 4.3.1.1 Flaws, deterioration, or other conditions (e.g. change of service, relocation, corrosion greater than the original corrosion allowance) that might adversely affect the performance or structural integrity of the shell of an existing tank must be evaluated and a determination made regarding suitability for intended service. Copyrighted material licensed to Buckeye Partners by Techstreet LLC, subscriptions.techstreet.com, downloaded on 2023-11-15 14:28:43 +0000 by Aaron Roth. No further reproduction or distribution is permitted. TANK INSPECTION, REPAIR, ALTERATION, AND RECONSTRUCTION 4-3 4.3.1.2 The evaluation of the existing tank shell shall be conducted by a storage tank engineer and shall include an analysis of the shell for the intended design conditions, based on existing shell plate thickness and material. The analysis shall take into consideration all anticipated loading conditions and combinations, including pressure due to fluid static head, internal and external pressure, wind loads, seismic loads, roof live loads, nozzle loads, settlement, and attachment loads. 4.3.1.3 Shell corrosion occurs in many forms and varying degrees of severity and may result in a generally uniform loss of metal over a large surface area or in localized areas. Pitting may also occur. Each case must be treated as a unique situation and a thorough inspection conducted to determine the nature and extent of corrosion prior to developing a repair procedure. Pitting does not normally represent a significant threat to the overall structural integrity of a shell unless present in a severe form with pits in close proximity to one another. Criteria for evaluating both general corrosion and pitting are defined below. 4.3.1.4 Methods for determining the minimum shell thickness suitable for continued operation are given in 4.3.2, 4.3.3, and 4.3.4 (see Section 6 for frequency of inspection). 4.3.1.5 If the requirements of 4.3.3 (welded) or 4.3.4 (riveted) cannot be satisfied, the corroded or damaged areas shall be repaired, or the allowable liquid level of the tank reduced, or the tank retired. The allowable liquid level for the continued use of a tank may be established by using the equations for a minimum acceptable thickness (see 4.3.3.1 and 4.3.4.1) and solving for height, H. The actual thickness, as determined by inspection, minus the corrosion allowance shall be used to establish the liquid level limit. The maximum design liquid level shall not be exceeded. 4.3.2 Actual Thickness Determination 4.3.2.1 For determining the controlling thicknesses in each shell course when there are corroded areas of considerable size, measured thicknesses shall be averaged in accordance with the following procedure (see Figure 4.1). a) For each area, the authorized inspector shall determine the minimum thickness, t2, at any point in the corroded area, excluding widely scattered pits (see 4.3.2.2). b) Calculate the critical length, L: In SI units: L =34 Dt 2 , but not more than 1000 millimeters where L is the maximum vertical length, in millimeters, over which hoop stresses are assumed to “average out” around local discontinuities; NOTE The actual vertical length of the corroded area may exceed L. D is the tank diameter, in meters; t2 is the least thickness, in millimeters, in an area of corrosion, exclusive of pits. In USC units: L = 3.7 Dt 2 , but not more than 40 inches where L is the maximum vertical length, in inches, over which hoop stresses are assumed to “average out” around local discontinuities; NOTE The actual vertical length of the corroded area may exceed L. D is the tank diameter, in feet; Copyrighted material licensed to Buckeye Partners by Techstreet LLC, subscriptions.techstreet.com, downloaded on 2023-11-15 14:28:43 +0000 by Aaron Roth. No further reproduction or distribution is permitted. 4-4 API STANDARD 653 tank diameter D t nom A t avg t2 L An area of corrosion a b c d e A Key SECTION A-A a – e are inspection planes Profile along Plane c , the selected by inspector. plane having the lowest average thickness, t 1. t 2 is the least min. thickness in entire area, exclusive of pits. Procedure 1) Determine t 2 2) Calculate L SI: L = 34 Dt 2, but not more than 1000 mm USC: L = 3.7 Dt 2, but not more than 40 in. 3) Locate L to get minimum t avg, which is t 1 Figure 4.1—Inspection of Corrosion Areas t2 is the least thickness, in inches, in an area of corrosion, exclusive of pits. c) The authorized inspector shall visually or otherwise decide which vertical plane(s) in the area is likely to be the most affected by corrosion. Profile measurements shall be taken along each vertical plane for a distance, L. In the plane(s), determine the lowest average thickness, t1, averaged over a length of L, using at least five equally spaced measurements over length L. d) See 4.3.3.1 for minimum permitted values for t1 and t2. The additional loads in 4.3.3.5 shall also be considered. e) The criteria for continued operation are as follows: i) the value t1 shall be greater than or equal to tmin (see 4.3.3 or 4.3.4), subject to verification of all other loadings listed in 4.3.3.5; ii) the value t2 shall be greater than or equal to 60 % of tmin; and iii) any corrosion allowance required for service until the time of the next inspection shall be added to tmin and 60 % of tmin. Copyrighted material licensed to Buckeye Partners by Techstreet LLC, subscriptions.techstreet.com, downloaded on 2023-11-15 14:28:43 +0000 by Aaron Roth. No further reproduction or distribution is permitted. TANK INSPECTION, REPAIR, ALTERATION, AND RECONSTRUCTION 4-5 4.3.2.2 Widely scattered pits may be ignored provided that: a) no pit depth results in the remaining shell thickness being less than one-half the minimum acceptable tank shell thickness exclusive of the corrosion allowance; and b) the sum of their dimensions along any vertical line does not exceed 50 mm in any 200 mm (2 in. in an 8 in.) length (see Figure 4.2). d1 200 mm d2 (8 in.) d3 d1 + d2 + d3PP LQ Figure 4.2—Pit Measurement 4.3.3 Minimum Thickness Calculation for Welded Tank Shell NOTE In general, the minimum acceptable thickness (tmin) for an entire shell course is determined using 4.3.3.1 a) with H determined to the bottom of each shell course and the results used as a basis for judging the suitability for continued service for the tank. If locally thinned areas are identified or if specific areas are investigated (such as for a shell nozzle installation), the method of 4.3.3.1 b) may be used to complete the evaluation with H determined for that particular location. 4.3.3.1 The minimum acceptable shell plate thickness for continued service shall be determined by one or more of the methods noted herein. These methods are limited to tanks with diameters equal to 200 ft or less. a) When determining the minimum acceptable thickness for an entire shell course, tmin is calculated as follows: 4.9 (H – 0.3 DG In SI units: t min = ------------------------------------------ SE where tmin is the minimum acceptable thickness, in millimeters for each course as calculated from the above equation; however, tmin shall not be less than 2.5 mm for any tank course; D is the nominal diameter of tank, in meters; H is the height from the bottom of the shell course under consideration to the maximum liquid level when evaluating an entire shell course, in meters; or Copyrighted material licensed to Buckeye Partners by Techstreet LLC, subscriptions.techstreet.com, downloaded on 2023-11-15 14:28:43 +0000 by Aaron Roth. No further reproduction or distribution is permitted. 4-6 API STANDARD 653 is the height from the bottom of the length L (see 4.3.2.1) from the lowest point of the bottom of L of the locally thinned area to the maximum liquid level, in meters; or is the height from the lowest point within any location of interest to the maximum liquid level, in meters; G is the highest specific gravity of the contents; S is the maximum allowable stress in MPa; use the smaller of 0.80Y or 0.429T for bottom and second course; use the smaller of 0.88Y or 0.472T for all other courses. Allowable shell stresses are shown Table 4.1 for materials listed in the current and previous editions of API 12C and API 650; NOTE for reconstructed tanks, S shall be in accordance with the current applicable standard; Y is the specified minimum yield strength of the plate; use 205 MPa if not known; T is the smaller of the specified minimum tensile strength of the plate or 550 MPa; use 380 MPa if not known; E is the original joint efficiency for the tank. Use Table 4.2 if original E is unknown. E = 1.0 when evaluating the retirement thickness in a corroded plate, when away from welds or joints by at least the greater of 25 mm or twice the plate thickness. 2.6 (H – 1 DG In USC units: t min = ------------------------------------- SE where tmin is the minimum acceptable thickness, in inches for each course as calculated from the above equation; however, tmin shall not be less than 0.10 inch for any tank course; D is the nominal diameter of tank, in feet; H is the height from the bottom of the shell course under consideration to the maximum liquid level when evaluating an entire shell course, in feet; or is the height from the bottom of the length L (see 4.3.2.1) from the lowest point of the bottom of L of the locally thinned area to the maximum liquid level, in feet; or is the height from the lowest point within any location of interest to the maximum liquid level, in feet; G is the highest specific gravity of the contents; S is the maximum allowable stress in lbf/in.2; use the smaller of 0.80Y or 0.429T for bottom and second course; use the smaller of 0.88Y or 0.472T for all other courses. Allowable shell stresses are shown Table 4.1 for materials listed in the current and previous editions of API 12C and API 650; NOTE for reconstructed tanks, S shall be in accordance with the current applicable standard; Y is the specified minimum yield strength of the plate; use 30,000 lbf/in.2 if not known; T is the smaller of the specified minimum tensile strength of the plate or 80,000 lbf/in.2; use 55,000 lbf/in.2 if not known; E is the original joint efficiency for the tank. Use Table 4.2 if original E is unknown. E = 1.0 when evaluating the retirement thickness in a corroded plate, when away from welds or joints by at least the greater of or twice the plate thickness. Copyrighted material licensed to Buckeye Partners by Techstreet LLC, subscriptions.techstreet.com, downloaded on 2023-11-15 14:28:43 +0000 by Aaron Roth. No further reproduction or distribution is permitted. TANK INSPECTION, REPAIR, ALTERATION, AND RECONSTRUCTION 4-7 b) When determining the minimum acceptable thickness for any other portions of a shell course (such as a locally thinned area or any other location of interest), tmin is calculated as follows: 4.9 HDG In SI units: t min = ------------------------ SE 2.6 HDG In USC units: t min = ------------------------ SE Table 4.1a—Maximum Allowable Shell Stresses, in SI Units (Not for Use for Reconstructed Tanks, See Note) Minimum Allowable Product Stress Allowable Hydrostatic Test Minimum Specified S (MPa) Stress St (MPa) Material Specified Grade Tensile Specification Yield Stress, Lower Two Upper Lower Two Upper Stress, Y (MPa) Courses Courses Courses Courses T (MPa) A283M C 205 380 163 179 180 185 A285M C 205 380 163 179 180 185 A36M — 250 400 172 189 189 208 A131M AB 235 400 172 189 189 208 A131M EH36 360 490 210 231 231 254 A573M 400 220 400 172 189 189 198 A573M 450 240 450 192 211 211 216 A573M 485 290 485 208 229 229 252 A516M 380 205 380 163 179 180 185 A516M 415 220 415 176 194 194 198 A516M 450 240 450 192 211 211 216 A516M 485 260 485 208 229 229 234 A662M B 275 450 193 212 212 234 A662M C 295 485 208 229 229 252 A537M 1 345 485 208 229 229 252 A537M 2 415 550 236 260 260 285 A663M CD 345 485 208 229 229 252 A841M 1 345 485 208 229 229 252 — 2 415 550 236 260 260 285 A678M A 345 485 208 229 229 252 — B 415 550 236 260 260 285 A737M B 345 485 208 229 229 252 A442M 380 205 380 163 179 179 185 — 415 220 415 176 194 194 198 CSA — — — — — — — G40,21M 260W 260 410 176 194 194 213 — 260WT 260 410 176 194 194 213 — 300W g 300 440 189 208 208 228 — 300W h 300 450 193 212 212 234 — 300WT g 300 440 189 208 208 228 — 300WT h 300 450 193 212 212 234 Copyrighted material licensed to Buckeye Partners by Techstreet LLC, subscriptions.techstreet.com, downloaded on 2023-11-15 14:28:43 +0000 by Aaron Roth. No further reproduction or distribution is permitted. 4-8 API STANDARD 653 Table 4.1a—Maximum Allowable Shell Stresses, in SI Units (Not for Use for Reconstructed Tanks, See Note) (Continued) Minimum Allowable Product Stress Allowable Hydrostatic Test Minimum Specified S (MPa) Stress St (MPa) Material Specified Grade Tensile Specification Yield Stress, Lower Two Upper Lower Two Upper Stress, Y (MPa) Courses Courses Courses Courses T (MPa) — 350W g 350 450 193 212 212 234 — 350W h 350 450 193 212 212 234 — 350WT g 350 480 206 227 227 249 — 350WT h 350 450 193 212 212 234 — — — — — — — — Unknown — NA NA 145 145 145 145 Known — Y T d d d d NOTE Allowable stresses for reconstructed tanks are tabulated in API 650, Table 5.2a or 5.2b, or calculated per 8.4. a Purposefully left blank. b Purposefully left blank. c Purposefully left blank. d This provision is for riveted tanks, constructed of known grades of material, evaluated per 4.3.4.2. For all courses, the maximum allowable shell stress for both product and hydrostatic test conditions are listed under column for allowable product stress, S. e Purposefully left blank. f The allowable stresses are calculated per 4.3.3.1 and 4.3.3.2 of this standard, unless otherwise noted. The calculated allowable stresses are rounded to the nearest megapascal. g These stress values are valid for CSA G40.21-04 and earlier materials. h These stress values are valid for CSA G40.21-13 materials. Table 4.1b—Maximum Allowable Shell Stresses, in USC Units (Not for Use for Reconstructed Tanks, See Note) Minimum Allowable Hydrostatic Minimum Allowable Product Stress, Material Specified Test Stress Specified S (lbf/in.2) f Specification and Tensile St (lbf/in.2) f Yield Stress, Grade Stress, Lower Two Upper Lower Two Upper Y (lbf/in.2) T (lbf/in.2) Courses Courses Courses Courses ASTM Specifications A283-C 30,000 55,000 23,600 26,000 26,000 27,000 A285-C 30,000 55,000 23,600 26,000 26,000 27,000 A36 36,000 58,000 24,900 27,400 27,400 30,100 A131-A, B, CS 34,000 58,000 24,900 27,400 27,400 30,100 A131-EH 36 51,000 71,000 30,500 33,500 33,500 36,800 A573-58 32,000 58,000 24,900 27,400 27,400 28,800 A573-65 35,000 65,000 27,900 30,700 30,700 31,500 A573-70 42,000 70,000 30,000 33,000 33,000 36,300 A516-55 30,000 55,000 23,600 26,000 26,000 27,000 A516-60 32,000 60,000 25,600 28,200 28,200 28,000 A516-65 35,000 65,000 27,900 30,700 30,700 31,500 A516-70 38,000 70,000 30,000 33,000 33,000 34,200 A662-B 40,000 65,000 27,900 30,700 30,700 33,700 Copyrighted material licensed to Buckeye Partners by Techstreet LLC, subscriptions.techstreet.com, downloaded on 2023-11-15 14:28:43 +0000 by Aaron Roth. No further reproduction or distribution is permitted. TANK INSPECTION, REPAIR, ALTERATION, AND RECONSTRUCTION 4-9 Table 4.1b—Maximum Allowable Shell Stresses, in USC Units (Not for Use for Reconstructed Tanks, See Note) (Continued) Minimum Allowable Hydrostatic Minimum Allowable Product Stress, Material Specified Test Stress Specified S (lbf/in.2) f Specification and Tensile St (lbf/in.2) f Yield Stress, Grade Stress, Lower Two Upper Lower Two Upper Y (lbf/in.2) T (lbf/in.2) Courses Courses Courses Courses A662-C 43,000 70,000 30,000 33,000 33,000 36,300 A537-Class 1 50,000 70,000 30,000 33,000 33,000 36,300 A537-Class 2 60,000 80,000 34,300 37,800 37,800 41,500 A633-C, D 50,000 70,000 30,000 33,000 33,000 36,300 A678-A 50,000 70,000 30,000 33,000 33,000 36,300 A678-B 60,000 80,000 34,300 37,800 37,800 41,500 A737-B 50,000 70,000 30,000 33,000 33,000 36,300 A841 50,000 70,000 30,000 33,000 33,000 36,300 A10 a 30,000 55,000 23,600 26,000 26,000 27,000 A7 a 33,000 60,000 25,700 28,300 28,300 29,700 A442-55 a 30,000 55,000 23,600 26,000 26,000 27,000 A442-60 a 32,000 60,000 25,600 28,200 28,200 28,800 CSA Specifications G40.21, 38W 38,000 60,000 25,700 28,300 28,300 31,100 G40.21, 44W g 44,000 65,000 27,900 30,700 30,700 33,700 G40.21, 44W h 44,000 64,000 27,400 30,200 30,700 33,200 G40.21, 50W 50,000 65,000 27,900 30,700 30,700 33,700 G40.21, 50WT g 50,000 70,000 30,000 33,000 33,000 36,300 G40.21, 50WT h 50,000 65,000 27,900 30,700 30,700 33,700 Unknown Material Specification and Grade Unknown (Note 2) 30,000 55,00 23,600 26,000 26,000 27,000 Riveted Tanks A7, A9, or A10 a c NA NA 21,000 21,000 21,000 21,000 Known d Y T d d d d Unknown e NA NA 21,000 21,000 21,000 21,000 NOTE Allowable stresses for reconstructed tanks are tabulated in API 650, Table 5.2a or 5.2b, or calculated per 8.4. a ASTM A7, ASTM A9, ASTM A10, and ASTM A442 are obsolete ASTM material specifications previously listed in API 12C and API 650. b The yield stress and tensile strength values shown are per API 653 for welded ASTM material of unknown origin. c This provision is for riveted tanks, constructed of any grade of material, evaluated per 4.3.4.1. d This provision is for riveted tanks, constructed of known grades of material, evaluated per 4.3.4.2. For all courses, the maximum allowable shell stress for both product and hydrostatic test conditions are listed under column for allowable product stress, S. e This provision is for riveted tanks, constructed of unknown grades of material, evaluated per 4.3.4.2. f The allowable stresses are calculated per 4.3.3.1 and 4.3.3.2 of this standard, unless otherwise noted. The calculated allowable stresses are rounded to the nearest 100 lbf/in.2. g These stress values are valid for CSA G40.21-04 and earlier materials. h These stress values are valid for CSA G40.21-13 materials. Copyrighted material licensed to Buckeye Partners by Techstreet LLC, subscriptions.techstreet.com, downloaded on 2023-11-15 14:28:43 +0000 by Aaron Roth. No further reproduction or distribution is permitted. 4-10 API STANDARD 653 Table 4.2a—Joint Efficiencies for Welded Joints, in SI Units Edition Type Joint Applicability Standard and Year of Joint Efficiency E or Limits Basic Butt 1.00 Standard Seventh and Later Annex A Butt 0.85 (1980 to Present) Spot RT Annex A Butt 0.70 No RT API 650 Basic Butt 0.85 Third to Sixth Standard (1966 to 1978) Annexes Butt 1.00 D or G Basic First and Second Butt 0.85 Standard (1961 to 1964) Butt 1.00 Annex D 14th and 15th — Butt 0.85 (1957 to 1958) — 3rd to 13th Lap a 0.75 10 mm max. t API 12C (1940 to 1956) Butt c 0.85 — Lap a 0.70 11 mm max. t First and Second Lap b 0.50 + k/5 6 mm max. t (1936 to 1939) Butt c 0.85

API 653 Nov 2023 Tank Inspection Standard PDF

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