Reconditioning of Metallic Gate, Globe, and Check Valves

API RECOMMENDED PRACTICE 621 THIRD EDITION, AUGUST 2010

REAFFIRMED, OCTOBER 2017

Reconditioning of Metallic Gate, Globe, and Check Valves

Downstream Segment

API RECOMMENDED PRACTICE 621 THIRD EDITION, AUGUST 2010

Special Notes

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Copyright © 2010 American Petroleum Institute

Foreword

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1. Scope 1

2. Normative References 1

3. Owner Access 2

4. Owner Responsibilities 2

   1. Valve Information 2

   2. Material Safety Data Sheet 2

   3. Preparation For Shipment To Reconditioner 2

   4. Valve Rerating 3

5. Inspection, Identification, and Disassembly of Valves 3

   1. General 3

   2. Identification Number 3

   3. Traveler Documents 3

   4. Disassembly and Cleaning of Valves 4

6. Repair of Valve Parts 4

   1. General 4

   2. Inspection of Valve Parts 5

   3. Handwheel Nut 6

   4. Handwheel 6

   5. Yoke 6

   6. Stem Nut and Stem Nut Housing 6

   7. Stem Nut Retainer 7

   8. Packing Gland Flange 7

   9. Packing Gland 7

   10. Back Seat Bushing 7

   11. Body and Bonnet 7

   12. Body Guides 12

   13. Body Seat Ring(s) 12

   14. Wedge Guides 12

   15. Wedge, Globe, Disc, and Clapper 12

   16. Stem 13

   17. Body-To-Bonnet Joint Bolting 14

   18. Packing Gland Eye Bolts 14

   19. Packing 14

   20. Body-To-Bonnet Joint Gasket 14

7. Post-Repair Assembly 15

8. Pressure Test 15

9. Preparation for Shipment 15

10. Tagging and Reconditioning Facility Identification 16

Annex A (normative) Stem Packing 17

Annex B (normative) Weld Overlay of Stems 23

Annex C (normative) Tests 25

v

Figures

1. Stuffing Box Clearances 18

2. Lantern Ring Arrangement 19

3. Flexible Graphite Packing for Block Valves 20

4. PTFE Vee Ring Packing for Block Valves 21

5. Lattice Braid PTFE Filament Packing for Block Valves 22

Tables

1. Minimum Thickness of Shell Wall and Minimum Diameter of Stem 9

2. Allowable Pitting and Localized Corrosion 10

3. Gasket Material and Surface Finish 11

4. Face-to-Face Dimensions 11

5. Minimum Wear Travel 13

Reconditioning of Metallic Gate, Globe, and Check Valves

1. Scope

   1. This recommended practice (RP) provides guidelines for reconditioning heavy wall (API 600 and API 594 type) carbon steel, ferritic alloy (up to 9 % Cr), stainless steel, and nickel alloy gate, globe, and check valves for ASME pressure classes 150, 300, 400, 600, 900, 1500, and 2500. Guidelines contained in this RP apply to flanged and butt weld cast or forged valves.

      
      

   2. It is an expectation of this RP that a contractual agreement shall be established between the Owner and the valve reconditioning facility. The reconditioning facility may be Original Equipment Manufacturer (OEM) owned/ operated, or directly associated and approved by the OEM. At the Owner’s option, an independent facility may be used. The Owner shall determine that the facility selected for valve reconditioning has a documented and established working Quality Assurance Program. The Quality Assurance Program should include the essential elements described in the ISO 9001 standard.

      
      

   3. This RP does not cover reconditioning or remanufacturing of used or surplus valves intended for resale. The only intent of this RP is to provide guidelines for refurbishing an end user’s (Owner) valves for continued service in the Owner’s facility. Valves reconditioned or remanufactured to this RP may not meet API Standard requirements for new valves. The correct application of a valve reconditioned to this RP remains the responsibility of the Owner.

      
      

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 591, Process Valve Qualification Procedure API Standard 594, Check Valves: Flanged, Lug, Wafer, and Butt-welding API Standard 598, Valve Inspection and Testing

API Standard 600 Steel Gate Valves—Flanged and Butt-welding Ends, Bolted Bonnets

ASME B1.3 1, Screw Thread Gaging Systems for Acceptability: Inch and Metric Screw Threads

ASME B1.5, Acme Screw Thread

ASME B1.8, Stub Acme Screw Threads

ASME B16.5, Pipe Flanges and Flanged Fittings

ASME B16.10, Face-to-Face and End-to-End Dimensions of Valves ASME B16.34, Valves—Flanged, Threaded, and Welding End ASME B31.3, Process Piping

1 ASME International, 3 Park Avenue, New York, New York 10016, www.asme.org.

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