Validation of Safety and Shutdown Valves for Sandy Service

API STANDARD 6AV1 THIRD EDITION, JULY 2018

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Contents

Page

1. Scope 1

2. Normative References 1

3. Terms, Definitions, and Abbreviations 1

   1. Terms and Definitions 1

   2. Abbreviations 2

4. Validation 3

   1. General 3

   2. Class II and Class III Valve Validation 3

   3. Test Agency 3

   4. Validation-Requirements 6

5. Test Procedures 12

   1. Class II Test Procedure 12

   2. Class III Test Procedure 16

6. Scaling of Test Results 21

   1. General 21

   2. Scaling of Class II Validation Results 21

   3. Scaling of Class III Validation Results 22

Bibliography 23

Figures

1. Example Piping Arrangement-Test Facility for Class II Valve Validation 5

2. Example Valve Validation Section Detail 6

3. Class II Validation Summary Flow Diagram 12

4. Class III Validation Summary Flow Diagram 16

Tables

1. Example Application 8

2. Example Class II Test Reporting Form 10

3. Example Class III Test Reporting Form 11

4. Initial Seal Test 13

5. Sand Slurry Flow Test 14

6. Sand Slurry Flow Test While Opening and Closing during Circulation 15

7. Initial Seal 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

v

Introduction

The validation of wellhead surface safety valves (SSVs), boarding shutdown valves (BSDVs), and underwater safety valves (USVs) is an important part of determining their fitness for service. In prior editions of API 6A and ISO 10423, the requirements for safety valve validation have been included as an annex in those documents. Recently, API Subcommittee 6 responsible for API 6A has determined that the industry is best served by having a separate specification for these validation tests to align with commercial practices. This separate document also allows regulators the possibility of referring to it without having to align with a specific edition of API 6A that might contain those requirements.

This edition of API 6AV1 contains the following major changes from prior editions:

• The title of the standard was changed from “Specification for Validation of Wellhead Surface Safety Valves and Underwater Safety Valve for Offshore Service” to “Validation of Safety and Shutdown Valves for Sandy Service.”

  
  

• The Scope was reworded to explain the intention of the tests for SSV, USV, and BSDV applications and to clarify that the validation of the actuator is outside the scope of this standard.

  
  

• The words “test valve” have replaced “SSV/USV valve” throughout the document to acknowledge the potential validation of BSDVs.

  
  

• For Class III, the wording “substantive change to the valve bonnet assembly” in the previous edition was clarified to read “substantive change to the valve stem seal.”

  
  

• The test agency is now required to conform to ISO 17025. Annex A (API Monogram Program) was removed.

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Validation of Safety and Shutdown Valves for Sandy Service

1. Scope

   
   

   There are three service classes, Class I, Class II, and Class III, for API 6A surface safety valve (SSV), underwater safety valve (USV), or boarding shutdown valve (BSDV). This standard establishes sandy service design validation for valves to meet Class II and Class III. Class II is intended to validate the valve bore sealing mechanism if substances such as sand can be expected to cause safety or shutdown valve failure. Class III adds additional requirements and validation of the bonnet assembly inclusive of stem seals.

   
   

   Validation of the actuator is outside the scope of this standard.

   
   

   NOTE This standard does not contain the validation requirements for Class I safety valves.

   
   

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 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

   
   

   ISO/IEC 17025 1,2, General requirements for the competence of testing and calibration laboratories

   
   

3. Terms, Definitions, and Abbreviations

3.1 Terms and Definitions

For the purposes of this document, the following terms and definitions apply.

3.1.1

actuator

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

3.1.2

failure

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

3.1.3

management system

Set of interrelated or interactive elements that establish policy and objectives and provide a means to achieve those objectives.

3.1.4

sandy service

Application where the retained fluid could contain particulates such as sand.

1 International Organization for Standardization, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva, Switzerland, www.iso.org.

2 International Electrotechnical Commission, 3 rue de Varembé, CH – 1211, Geneva, Switzerland, https://www.iec.ch.

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