Safe Use of 2-inch Hammer Unions for Oilfield Applications

API RECOMMENDED PRACTICE 7HU1 FIRST EDITION, MAY 2009

ERRATA, FEBRUARY 2014

REAFFIRMED, FEBRUARY 2020

Safe Use of 2-inch Hammer Unions for Oilfield Applications

Upstream Segment

API RECOMMENDED PRACTICE 7HU1 FIRST EDITION, MAY 2009

ERRATA, FEBRUARY 2014

REAFFIRMED, FEBRUARY 2020

Special Notes

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Users of this Recommended Practice (RP) should not rely exclusively on the information contained in this document. Sound business, scientific, engineering, and safety judgement should be used in employing the information contained herein.

API is not undertaking to meet the duties of employers, manufacturers, or suppliers to warn and properly train and equip their employees, and others exposed, concerning health and safety risks and precautions, nor undertaking their obligations to comply with authorities having jurisdiction.

Information concerning safety and health risks and proper precautions with respect to particular materials and conditions should be obtained from the employer, the manufacturer or supplier of that material, or the material safety data sheet.

Work sites and equipment operations may differ. Users are solely responsible for assessing their specific equipment and premises in determining the appropriateness of applying the RP. At all times users should employ sound business, scientific, engineering, and judgement safety when using this RP.

API publications may be used by anyone desiring to do so. Every effort has been made by the Institute to assure the accuracy and reliability of the data contained in them; however, the Institute makes no representation, warranty, or guarantee in connection with this publication and hereby expressly disclaims any liability or responsibility for loss or damage resulting from its use or for the violation of any authorities having jurisdiction with which this publication may conflict.

API publications are published to facilitate the broad availability of proven, sound engineering and operating practices. These publications are not intended to obviate the need for applying sound engineering judgment regarding when and where these publications should be utilized. The formulation and publication of API publications is not intended in any way to inhibit anyone from using any other practices.

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Copyright © 2009 American Petroleum Institute

Foreword

This recommended practice (RP) is under the jurisdiction of the American Petroleum Institute (API) Subcommittee on Drilling Structures and Equipment (SC8).

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Suggested revisions are invited and should be submitted to the Standards Department, API, 1220 L Street, NW, Washington, D.C. 20005, standards@api.org.

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Contents

Page

1. Scope 1

   1. General 1

   2. Objective 1

2. Terms, Definitions, and Abbreviations 1

   1. Terms and Definitions 1

   2. Abbreviations 3

3. Mismatch Description 3

   1. General 3

   2. Example of the Hazard 3

   3. Mismatching 2-inch Figure 402, Figure 602 and, Figure 1002 with 2-inch Figure 1502 3

4. Description of the Engineering Design Solution 4

   1. General 4

   2. Reduced Thread Major Diameter 5

   3. Raised Shoulder 5

   4. Mark Indicating Design 5

5. Measures to Prevent the Make-up of Mismatched Components 6

   1. General 6

   2. Replace all 2-inch Hammer Union Components in Fleet to 2-inch Figure 1502 6

   3. Go/No-go Gauges 6

   4. Inspection and Marking 7

   5. Training 8

   6. Management of Change (MOC) 9

   7. Permit-to-work (PTW) and/or Job Safety Analysis (JSA) 9

   8. Job Site Inventory of Hammer Union Components 10

   9. Color-coding 10

6. Mitigating the Effects of Mismatched Components Parting Explosively 10

7. General Safety Recommendations 10

   1. General 10

   2. Personal Protective Equipment (PPE) 10

   3. Inspection, Maintenance, and Testing 10

   4. Mixing Hammer Union Components from Different Manufacturers 11

   5. Documented Safe Practices 11

   6. Pressure Rating Consideration for Dynamic Conditions 11

   7. Other Mismatch Combinations 11

   8. System vs Component Pressure Rating and Service Application 11

   9. Newly Manufactured Equipment not Conforming to New Engineering Design Solution 11

Bibliography 12

Figures

1. Mismatched Male Union Sub and Wing Nut Threaded to a Female Union Sub 4

2. Reduction of External Thread Major Diameter 5

3. Raised Shoulder on New Engineering Design Compared to Original Design without

   Raised Shoulder 6

4. Marked Raised Shoulder on New Engineering Design Compared to the Original Geometry 7

5. Go/No-go Gauge Ring Not Accepting a 2-inch Figure 1502 Threads 8

6. Go/No-go Gauge Ring Accepting a 2-inch Figure 402, Figure 602, and Figure 1002 Threads 9

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