Specification for Validation of Wellhead Surface Safety Valves and Underwater Safety Valves for Offshore Service

API SPECIFICATION 6AV1

SECOND EDITION, FEBRUARY 2013

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Foreword

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Contents

Page

1. Scope 1

2. Normative References 1

3. Definitions and Abbreviations 1

   1. Definitions 1

   2. Abbreviations 2

4. Validation 2

   1. General 2

   2. Class II and Class III SSV/USV Valve Validation 3

   3. Test Agency 3

   4. Validation—Requirements 5

5. Test Procedures 12

   1. Class II Validation Test Summary 12

   2. Class II Test Procedure 13

   3. Class III Validation Test Summary 13

   4. Class III Test Procedure17

6. Scaling of Test Results 21

   1. Scaling of Class II Validation Results 21

   2. Scaling of Class III Validation Results 21

Annex A (informative) API Monogram Program 23

Bibliography 25

Figures

1. Example Piping Arrangement—Test Facility for Class II SSV/USV Valve Validation 5

2. Example SSV/USV Valve Validation Section Detail 6

3. Class II SSV/USV Validation Summary Flow Diagram 12

4. Class III Validation Summary Flow Diagram 13

Tables

1. Example Application SSV/USV Valve Validation 8

2. Example Class II SSV/USV Valve Test Reporting Form 10

3. Example Class III SSV/USV Valve Test Reporting Form 11

4. Initial Leakage Test 14

5. Sand Slurry Flow Test 15

6. Sand Slurry Flow Test While Opening and Closing During Circulation 16

7. Initial Leakage Test 17

8. Class III Sand Slurry Flow Rates 18

9. Class III Sand Slurry Flow Test 19

10. Sand Slurry Flow Test While Opening and Closing During Circulation 20

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Specification for Validation of Wellhead Surface Safety Valves and Underwater Safety Valves for Offshore Service

1. Scope

   
   

   This specification establishes design validation requirements for API 6A surface safety/underwater safety valves (SSV/USV) and associated valve bore sealing mechanism(s) for Class II and Class III. These classes are intended for use if substances such as sand can be expected to cause an SSV/USV valve failure. Class III adds requirements for the validation of the valve bonnet assembly inclusive of stem seals and may be selected by the user/purchaser. Validation to Class III also validates the same SSV/USV for Class II.

   
   

   NOTE Previous editions of this document included reference to and requirements for verification to PR1, standard service (Class I).

   
   

2. Normative References

   
   

   The following referenced documents are indispensable for the application of this specification. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

   
   

   API Manual of Petroleum Measurement Standards (MPMS) Chapter 10.4, Determination of Sediment and Water in Crude Oil by the Centrifuge Method (Field Procedure)

   
   

   API Specification 6A, Specification for Wellhead and Christmas Tree Equipment

   
   

   API Recommended Practice 13B-1, Recommended Practice for Field Testing Water-based Drilling Fluids

   
   

3. Definitions and Abbreviations

3.1 Definitions

The definitions below are related specifically to surface safety and underwater safety valves and are presented to define the terminology used in this specification.

3.1.1

failure

Improper performance of a device or equipment item that prevents completion of its design function.

3.1.2

SSV/USV actuator

Device that causes the SSV/USV valve to open when power is supplied and to automatically close when power is lost or released.

3.1.3

SSV/USV valve

Subassembly of the SSV/USV that contains the wellstream and shuts off the flow when closed.

3.1.4

substantive change

Change identified by the manufacturer that affects the performance of the product in the intended service.

1