Specification for Valves

API SPECIFICATION 6D

TWENTY-FIFTH EDITION, NOVEMBER 2021

API MONOGRAM PROGRAM EFFECTIVE DATE: NOVEMBER 2022

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Copyright © 2021 American Petroleum Institute

Foreword

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Contents

Page

1. Scope 1

2. Normative References 1

3. Terms, Definitions, Acronyms, Abbreviations, Symbols, and Units 4

   1. Terms and Definitions 4

   2. Acronyms and Abbreviations 10

   3. Symbols and Units 12

4. Application, Configuration, and Performance 12

   1. Valve Types 12

   2. Conformance and General Performance Requirements 14

   3. Pressure and Temperature Rating 14

   4. Valve Bore 15

   5. Manufacturing Processes 17

5. Design 18

   1. General 18

   2. Dimensions 19

   3. Drive Train 22

   4. Operations 23

   5. Cavity Pressure Relief 25

   6. Body Penetrations 25

   7. Stem Retention 26

   8. Antistatic 27

   9. Lifting 27

   10. Design Process 27

6. Materials 28

   1. Metallic Requirements 28

   2. Nonmetallic Requirements 28

   3. Composition Limits 29

   4. Tensile Test Requirements 29

   5. Impact Test 30

   6. Sour Service 31

   7. Body Penetrations 31

   8. Production Heat-treating Equipment. 31

7. Welding 33

   1. General 33

   2. Outsourced Welding 33

   3. Consumables 33

   4. Qualification 34

   5. Weld Overlay 34

   6. Impact Testing 35

   7. Hardness Testing 37

   8. Visual Inspection Welds to Pressure-containing Parts 37

   9. Visual Inspection Pressure-containing and Pipe Pup Welds 37

   10. NDE Pipe Pup-to-Valve Welds 37

   11. Manufacturing Repair 38

8. Bolting 39

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   1. Pressure-Boundary Bolting 39

   2. Other Bolting 39

9. Quality Control 39

   1. Measuring and Test Equipment Control 39

   2. Pressure-measuring Device 39

   3. Welding Inspectors 40

   4. Visual Inspection 40

   5. Storage for Nonmetallic Seals 41

   6. Valve Assembly 41

10. Factory Acceptance Testing 42

    1. Pressure Testing—General 42

    2. Stem Backseat Test 43

    3. Hydrostatic Shell Test 44

    4. Hydrostatic Seat Test 45

    5. Hydrostatic Test-Cavity Relief Valve 46

11. Coating/Painting 47

12. Marking 47

    1. General 47

    2. Valve Size Marking 49

    3. Nameplate 49

    4. Supplemental Requirements 51

13. Draining, Protection, and Preparation for Transport 51

    1. Draining 51

    2. Protection 51

    3. Preparation for Transport 52

14. Documentation 52

    1. Minimum Documentation and Retention 52

    2. Documentation Provided with the Valve 52

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Contents

Page

Annex A (informative) Repair or Remanufacture of Valves 54

Annex B (informative) Examples of Valve Configurations 70

Annex C (normative) Valve End-to-end and Face-to-face Dimensions 87

Annex D (informative) Guidance for Travel Stops by Valve Type 111

Annex E (informative) Isolation Valve Features 112

Annex F (informative) Design Validation 115

Annex G (normative) External Coating for End Connectors 127

Annex H (normative) Heat-treat Equipment Qualification 130

Annex I (normative) Quality Specification Level (QSL) and Supplemental Testing 132

Annex J (informative) Requirements for Extended Hydrostatic Shell Test Duration

and Records Retention for Valves in Jurisdictional Pipeline Systems 143

Annex K (normative) Purchaser-specified Customization—Permissible Deviations

to Specified Design and Manufacturing Requirements 145

Annex L (informative) Specified Customization—Supplemental Options

to Specified Design and Manufacturing Requirements 148

Bibliography 160

Figures

1. Typical Flange Dimension 20

2. Bolt-hole Misalignment of Flange Across Valve 21

3. Charpy V-notch Weld Metal Specimen Location 36

4. Charpy V-notch Heat-affected Zone Specimen Location 36

5. Typical Identification Plate for a Valve with One Seat Unidirectional and One Seat Bidirectional 51

1. Axial Valve 71

2. Ball Valve (Floating) 72

3. Ball Valve (Side-entry Trunnion Mounted) 73

4. Ball Valve (Top-entry Trunnion Mounted) 74

5. Ball Valve (Welded-body Trunnion Mounted) 75

6. Check Valve (Axial Flow) 76

7. Check Valve (Full-opening Swing) 77

8. Check Valve (Long Pattern, Single-plate Wafer-type) 78

9. Check Valve (Long Pattern, Typical Dual-plate Wafer-type) 79

10. Check Valve (Piston) 80

11. Swing Check Valve (Reduced-opening) 81

12. Check Valve (Short Pattern, Single-plate Wafer-type) 82

13. Gate Valve (Expanding-gate/Rising-stem) 83

14. Gate Valve (Slab-gate/Through-conduit Rising-stem) 84

15. Plug Valve 85

16. Rising Stem Ball Valve 86

1. Block and Bleed—Type A 113

2. Block and Bleed—Type B 113

3. Double Block and Bleed—Type A 113

4. Double Block and Bleed—Type B 114

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5. Double Isolation and Bleed—Type A 114

6. Double Isolation and Bleed—Type B 114

F.1 Test Procedure for Pressure Temperature Cycle 124

1. Raised Face 127

2. Ring Type Joint or Raised-face Ring Type Joint 128

3. Weld End 128

4. Pipe Pup Weld Ends 129

1. Thermocouple Locations—Rectangular Furnace (Working Zone) 130

2. Thermocouple Locations—Cylindrical Furnace (Working Zone) 131

1. Pressure Balance Hole for Ball Valve (Typical) 157

2. Pressure Balance Hole for Gate Valve (Typical) 157

Tables

1. Minimum Bore for Full-opening Valves 16

2. Process Control Requirements 17

3. Sizes for Drain 26

4. Minimum V-notch Impact Requirements for Material other than Duplex and Super Duplex

   Stainless Steel (Full-size Specimen) 30

5. Minimum V-notch Impact Requirements for Duplex and Super Duplex Stainless Steel

   (Full-size Specimen) 30

6. Adjustment Factors for Subsize Impact Specimens 31

7. Heat Treatment Thermal Uniformity Survey (TUS) Requirements 32

8. Minimum Duration of Stem Backseat Tests 43

9. Minimum Duration of Hydrostatic Shell Tests 44

10. Minimum Duration of Hydrostatic Seat Tests 45

11. Valve Marking on Body 48

12. Additional Marking 49

13. Valve Marking on Nameplate 50

1. Initial Inspection 56

2. Items for Photographic Inspection 56

3. Disassembly of Ball Valve with Seat Leakage 58

4. Requirements for Evaluation of Components 60

5. Requirements for Replacement Parts of Non-OEM Parts 65

6. Nameplate Marking Requirements 68

1. Axial Valves—Face-to-face (A) and End-to-end (B and C) Dimensions 88

2. Ball Valves (Side Entry only)—Face-to-face (A) and End-to-end (B and C) Dimensions 91

3. Check Valves and Axial Check Valves (Full Opening and Reduced Types)—

   Face-to-face (A) and End-to-end (B and C) Dimensions 96

4. Check Valves (Single- and Dual-plate, Long- and Short-pattern, Wafer-type,

   and Double Flanged)—Face-to-face Dimensions 101

5. Gate Valves—Face-to-face (A) and End-to-end (B and C) Dimensions 103

6. Plug Valves—Face-to-face (A) and End-to-end (B and C) Dimensions 106

D.1 Valve Travel Stops 111

E.1 Isolation Valve Types 112

1. Design Validation for Valves 121

2. Minimum Percentage of Pressure During Opening Phase 122

1. NDE Requirements 133

2. Extent, Method, and Acceptance Criteria of NDE/Item Examination C134ode 134

3. Production Materials Requirements 135

   Contents

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4. Testing Sequence for Quality Specification 136

5. Minimum Duration of Gas Shell Tests 140

6. Documentation Requirements for Each QSL 142

1. Stabilization Period Duration 154

2. Minimum Duration of Gas Shell Tests 155

Introduction

Changes from the 24th to the 25th Edition

This specification is the result of updating the requirements from API Specification 6D, 24th Edition, including Addendum 1 and Addendum 2. The revision of API 6D, 25th Edition, was developed based on input from the API 6D Task Group technical experts globally. The technical revisions have been made to accommodate the needs of industry and address many interpretations to move this specification to a higher level of service to the petroleum and natural gas industry. Highlights of some of the significant changes between the 24th edition and 25th edition, include:

• changing the title of the specification;

  
  

• reorganizing the specification requirements in an order more aligned with the manufacturing process;

  
  

• the addition of axial valves to the types of valves covered by this specification;

  
  

• the removal of Class 400 as a standard pressure class;

  
  

• requiring conformance to API 6DX for valves supplied with actuators;

  
  

• identifying allowable adjustments for subsize impact specimens;

  
  

• identifying minimum heat treatment requirements;

  
  

• identifying minimum bolting requirements;

  
  

• revising marking requirements;

  
  

• providing updated design validation guidance;

  
  

• addition of requirements for repair and remanufacture of valves from API 6DR in new Annex A;

  
  

• collecting all purchaser-specified requirements into annexes (Annex K and Annex L);

  
  

• combining QSL requirements from the 24th edition (Annexes I, J and L into one annex [Annex I]);

  
  

• adding guidance through-out the document reference to API 20 series specifications and standards.

Units of Measurement

In this standard, data are expressed in both U.S. customary (USC) and metric (SI) units.

Rounding

Except as otherwise required by this specification, to determine conformance with the specified requirements, observed or calculated values are rounded to the nearest unit in the last right-hand place of figures used in expressing the limiting value, in conformance with the rounding method of ASTM E29 or ISO 80000-1, Annex B, Rule A.

Specification for Valves

1. Scope

   
   

   This specification defines the requirements for the design, manufacturing, materials, welding, quality control, assembly, testing, marking, documentation, and process controls of axial, ball, check, gate, and plug valves for application in the petroleum and natural gas industries.

   
   

   This specification applies to ASME Class 150, 300, 600, 900, 1500, and 2500.

   
   

   NOTE ASME Class 400 has been removed from this specification.

   
   

   API 6DR for repair and remanufacture of valves has been withdrawn and has been replaced by Annex A. Annexes A, B, D, E, F, J, and L are informative and contain optional requirements used in this specification. Annexes C, G, H, I, and K are normative and are mandatory in the use of this specification.

   Information marked “NOTE” are not requirements but are provided for guidance in understanding or clarifying the associated requirement.

   
   

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, except that new editions may be used on issue and shall become mandatory upon the effective date specified by the publisher or 6 months from the date of the revision (where no effective date is specified).

AMPP (formerly NACE)1

NACE MR0175/ISO15156 (all parts), Petroleum and natural gas industries—Materials for use in H2S- containing environments in oil and gas production

API

API Standard 6DX, Standard for Actuators and Mounting Kits for Valves

API Specification 6FA, Specification for Fire Test for Valves

API Specification 20A, Carbon Steel, Alloy Steel, Stainless Steel, and Nickel Base Alloy Castings for Use in the Petroleum and Natural Gas Industry, 2nd Edition

API Specification 20B, Open Die Shaped Forgings for Use in the Petroleum and Natural Gas Industry, 1st Edition

API Specification 20C, Closed Die Forgings for Use in the Petroleum and Natural Gas Industry, 3rd Edition

1 Association for Material Protection and Performance (formerly NACE International), 1440 South Creek Drive, Houston, Texas 77084-4906, www.nace.org.