AWS C4.3/C4.3M:2018

An American National Standard

Recommended Practices for Oxyfuel Gas Heating Torch Operation

AWS C4.3/C4.3M:2018

An American National Standard

Approved by the American National Standards Institute

June 6, 2017

Recommended Practices for Oxyfuel Gas Heating

Torch Operation

4th Edition

Supersedes AWS C4.3/C4.3M:2007

Prepared by the American Welding Society (AWS) C4 Committee on Oxyfuel Gas Welding and Cutting

Under the Direction of the AWS Technical Activities Committee

Approved by the AWS Board of Directors

Abstract

The newly revised manual for oxyfuel gas heating torch operation includes the latest procedures to be used in conjunc- tion with oxyfuel gas heating equipment. The manual also includes the latest safety requirements. Complete lists of equipment are available from individual manufacturers.

ISBN: 978-0-87171-915-7

© 2017 by American Welding Society

All rights reserved Printed in the United States of America

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All standards (codes, specifications, recommended practices, methods, classifications, and guides) of the American Welding Society (AWS) are voluntary consensus standards that have been developed in accordance with the rules of the American National Standards Institute (ANSI). When AWS American National Standards are either incorporated in, or made part of, documents that are included in federal or state laws and regulations, or the regulations of other governmental bodies, their provisions carry the full legal authority of the statute. In such cases, any changes in those AWS standards must be approved by the governmental body having statutory jurisdiction before they can become a part of those laws and regulations. In all cases, these standards carry the full legal authority of the contract or other document that invokes the AWS standards. Where this contractual relationship exists, changes in or deviations from requirements of an AWS standard must be by agreement between the contracting parties.

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Official interpretations of any of the technical requirements of this standard may only be obtained by sending a request, in writing, to the appropriate technical committee. Such requests should be addressed to the American Welding Society, Attention: Managing Director, Standards Development, 8669 NW 36 St, # 130, Miami, FL 33166 (see Annex D). With regard to technical inquiries made concerning AWS standards, oral opinions on AWS standards may be rendered. These opinions are offered solely as a convenience to users of this standard, and they do not constitute professional advice. Such opinions represent only the personal opinions of the particular individuals giving them. These individuals do not speak on behalf of AWS, nor do these oral opinions constitute official or unofficial opinions or interpretations of AWS. In addition, oral opinions are informal and should not be used as a substitute for an official interpretation.

This standard is subject to revision at any time by the AWS C4 Committee on Oxyfuel Gas Welding and Cutting. It must be reviewed every five years, and if not revised, it must be either reaffirmed or withdrawn. Comments (recommendations, additions, or deletions) and any pertinent data that may be of use in improving this standard are required and should be addressed to AWS Headquarters. Such comments will receive careful consideration by the AWS C4 Committee on Oxyfuel Gas Welding and Cutting and the author of the comments will be informed of the Committee’s response to the comments. Guests are invited to attend all meetings of the AWS C4 Committee on Oxyfuel Gas Welding and Cutting to express their comments verbally. Procedures for appeal of an adverse decision concerning all such comments are provided in the Rules of Operation of the Technical Activities Committee. A copy of these Rules can be obtained from the American Welding Society, 8669 NW 36 St, # 130, Miami, FL 33166.

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Personnel

AWS C4 Committee on Oxyfuel Gas Welding and Cutting

L. L. Liston, Chair Consultant

1. F. Johnson, Vice Chair Miller Electric Manufacturing Company

   1. Naumann, Secretary American Welding Society

J. F. Henderson Victor Technologies, Incorporated

M. J. Hogan The Harris Products Group, A Lincoln Electric Company

R. K. Langford Victor Technologies, Incorporated

1. R. McGowan McGowan Technical Services, Incorporated

2. B. Overvaag Miller Electric Manufacturing Company

J. C. Papritan The Ohio State University

A. T. Sheppard The DuRoss Group

Advisors to the AWS C4 Committee on Oxyfuel Gas Welding and Cutting

J. D. Compton J. C. & Associates

M. E. Owens Columbus State Community College

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Foreword

This foreword is not part of this standard but is included for information purposes only.

This manual is intended for use by the oxyfuel gas heating torch operator. It describes the oxyfuel gas heating torch operation process, including information relating to equipment, safety, and operating procedures.

Although many references are made to safe practice throughout this manual, it is strongly recommended that all opera- tors become thoroughly familiar with all aspects of a safe oxyfuel heating operation. A suggested standard is ANSI Z49.1, Safety in Welding, Cutting, and Allied Processes, available from the American Welding Society.

Much of the information in this manual is necessarily general in nature due to the large number of variations in equip- ment produced by various manufacturers. The manufacturer’s manual should be consulted for details on safe installation and use of all equipment. When equipment, or parts of equipment, need repair, the work shall be performed by personnel who have been properly instructed by the manufacturers of the equipment.

A vertical line in the margin or underlined text in clauses, tables, or figures indicates an editorial or technical change from the 2007 edition.

Comments and suggestions for the improvement of this standard are welcome. They should be sent to the Secretary, AWS C4 Committee on Oxyfuel Gas Welding and Cutting, American Welding Society, 8669 NW 36 St, # 130, Miami, FL 33166.

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Table of Contents

Page No.

Personnel vii

Foreword ix

List of Tables xii

List of Figures xii

1. General Requirements 1

   1. Scope 1

   2. Units of Measure 1

   3. Safety 1

2. Normative References 2

3. Terms and Definitions 3

4. Equipment and Supplies 3

   1. Oxygen Supply 3

   2. Fuel Supply 4

   3. Maximum Acetylene Pressure 5

   4. Pressure Regulators 5

   5. Hoses and Fittings 7

   6. Heating Torches 8

   7. Heating Tip/Head 8

   8. Maintenance of Heating Tips or Heads 10

   9. Personal Protective Equipment (PPE) 10

   10. Additional Safety Equipment 10

   11. Safe Use, Handling, and Storage of Gas Cylinders 10

   12. Safe Working Environment 11

5. Startup and Shutdown Procedures 12

   1. Setting Up Equipment 12

   2. Lighting the Torch 14

   3. Equipment Shutdown 15

6. Flame Adjustment 15

   1. Types of Flames 15

   2. Backfire, Sustained Backfire, and Flashback Safety Note 16

7. Flame Heating Procedures 17

   1. Testing 17

   2. Troubleshooting 17

8. Flashback Arrestors and Check Valves 17

   1. Flashback Arrestors 17

   2. Check Valves 17

   3. What to do in the Event of a Flashback 17

   4. Flashback Prevention 17

Page No.

Annex A (Informative)—Informative References 19

Annex B (Informative)—Fuel Gas Withdrawal Rates 21

Annex C (Informative)—Fuel Gases 23

Annex D (Informative)—Requesting an Official Interpretation on an AWS Standard 25

List of AWS Documents on Oxyfuel Gas Welding and Cutting 27

List of Tables

Table Page No.

1. Acetylene Withdrawal 21

2. Propylene Withdrawal 22

3. Propane Withdrawal 22

List of Figures

Figure Page No.

1. Oxygen Cylinder 4

2. Typical Fuel Gas Cylinders 5

3. Pressure Regulators 6

4. Hoses and Fittings 7

5. Manual Heating Torch 8

6. Multi-Flame Heating Heads 9

7. Water-Cooled Flame Hardening Head 9

8. Carburizing Flame 16

9. Neutral Flame 16

10. Oxidizing Flame 16

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Recommended Practices for Oxyfuel Gas Heating Torch Operation

1. General Requirements

   1. Scope. This manual describes the equipment, procedures, and safe practices for oxyfuel gas heating torch operation. It is written for the operators of torches using single or multiple heating tips and heads. It is also recommended for man- agement personnel associated with the oxyfuel gas heating torch operation and process.

      Oxyfuel heating is an operation whereby various metals are heated in order to perform the following operations:

      1. Straightening and bending with mechanical force

      2. Flame straightening and cambering

      3. Stress relieving

      4. Preweld and postweld heating

      5. Fusion of coatings

      6. Flame hardening

      7. Flame shrinking

         The metal is heated by the direct application of single- or multi-flames to a desired elevated temperature. The heating process may be applied to all types of metal forms or shapes. An operator can make proper compensation for the effect of the metallurgical conditions, part geometry, and physical changes that may occur during the heating process.

         In general, torch heating does not require any lengthy startup. Operations can be performed in most locations, in con- fined areas, under most conditions, and with relatively low-cost equipment. Torch heating can also be performed on completed structures without dismantling them. Although this recommended practice is not written with mandatory requirements, mandatory language, such as the use of “shall,” will be found in those portions of the document where failure to follow the instructions or procedures could produce inferior, misleading, or unsafe results.

   2. Units of Measure. This standard makes use of both U.S. Customary Units and the International System of Units (SI). The latter are shown within brackets ([ ]) or in appropriate columns in tables and figures. The measurements may not be exact equivalents; therefore, each system must be used independently.

   3. Safety. Safety issues and concerns are addressed in this standard although health issues and concerns are beyond the scope of this standard. Safety and health information is available from the following sources:

      American Welding Society:

      1. ANSI Z49.1, Safety in Welding, Cutting, and Allied Processes

      2. AWS Safety and Health Fact Sheets

      3. Other safety and health information on the AWS website Material or Equipment Manufacturers:

(1) Safety Data Sheets supplied by materials manufacturers (2) Operating Manuals supplied by equipment manufacturers