AWS D18.1/D18.1M:2009

An American National Standard

Specification for Welding of Austenitic Stainless Steel Tube and Pipe Systems in Sanitary (Hygienic) Applications

AWS D18.1/D18.1M:2009

An American National Standard

Approved by the American National Standards Institute

April 17, 2009

Specification for Welding of Austenitic Stainless Steel Tube and Pipe Systems in Sanitary (Hygienic) Applications

2nd Edition

Supersedes AWS D18.1:1999

Prepared by the American Welding Society (AWS) D18 Committee on Welding in Sanitary Applications

Under the Direction of the AWS Technical Activities Committee

Approved by the AWS Board of Directors

Abstract

This specification provides the requirements for welds in tubing systems in dairy and other food processing plants. The document addresses qualifications, fabrication, extent of visual examination, acceptance criteria, and documentation requirements.

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International Standard Book Number: 978-0-87171-749-8

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© 2009 by American Welding Society

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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 govern- mental 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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On occasion, text, tables, or figures are printed incorrectly, constituting errata. Such errata, when discovered, are posted on the AWS web page (www.aws.org).

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, Technical Services Division, 550 N.W. LeJeune Road, Miami, FL 33126 (see Annex A). 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 D18 Committee on Welding in Sanitary Applications. 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 D18 Committee on Welding in Sanitary Applications 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 D18 Committee on Welding in Sanitary Applications 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, 550 N.W. LeJeune Road, Miami, FL 33126.

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Dedication

The D18 Committee on Welding in Sanitary Applications dedicates this edition of the D18.1/D18.1M:2009, Specification for Welding of Austenitic Stainless Steel Tube and Pipe Systems in Sanitary (Hygienic) Applications, to Mr. Garrett M. Naughton, a charter member of the D18 Committee. Garrett was a true friend and advocate of the American Welding Society. His dedicated efforts did much to advance the art and science of welding stainless steel materials for the food and food processing industry, as well as the education and training of welders for the welding industry.

The D18 Committee on Welding in Sanitary Applications dedicates this edition of the D18.1/D18.1M:2009, Specification for Welding of Austenitic Stainless Steel Tube and Pipe Systems in Sanitary (Hygienic) Applications, to Mr. Garrett M. Naughton, a charter member of the D18 Committee. Garrett was a true friend and advocate of the American Welding Society. His dedicated efforts did much to advance the art and science of welding stainless steel materials for the food and food processing industry, as well as the education and training of welders for the welding industry.

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Personnel

AWS D18 Committee on Welding in Sanitary Applications

J. E. Campbell, Chair WeldTech Solutions Corporation

W. L. Roth, 1st Vice Chair The Procter & Gamble Company

R. Howard, 2nd Vice Chair Vogt Power International

R. Starks, Secretary American Welding Society

R. E. Avery Nickel Institute

R. D. Campbell Bechtel National, Incorporated

L. Hanson Johnsonville Sausage, LLC

B. K. Henon Arc Machines, Incorporated

E. K. Johnson Acraline

M. J. LeRoy Swagelok Corporation

J. McSwiggin Rodem, Incorporated

J. Williams James Williams, PC

Advisors to the AWS D18 Committee on Welding in Sanitary Applications

L. P. Connor Consultant

J. R. Hannahs Professor

M. P. Lang Bechtel Corporation

G. B. Melton TWI

J. R. Miller Retired

R. K. Smith Richard K. Smith

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Foreword

This foreword is not part of AWS D18.1/D18.1M:2009, Specification for Welding of Austenitic Stainless Steel Tube and Pipe Systems in Sanitary (Hygienic) Applications, but is included for informational purposes only.

The formation of D18 Committee was approved in October and November 1995 by the Technical Activities Committee and the Board of Directors, respectively. The Committee was formed to respond to the request of the 3-A Sanitary Standards Committee for help in preparing welding standards for use in the manufacture and construction of dairy and food product processing plants. The 3-A Sanitary Standards Inc. (3-A SSI) Committees develop and promulgate sanitary design standards for dairy and food processing, packaging, and handling equipment and systems. Several members of the Committee are active members of 3-A, and the Committee has maintained liaison with 3-A.

This document supersedes AWS D18.1:1999, Specification for Welding of Austenitic Stainless Steel Tube and Pipe Systems in Sanitary (Hygienic) Applications. Principal changes in the second edition involve enhancements to the sections on welding procedure qualifications and qualification records.

The D18 Committee has adopted AWS B2.1, Specification for Welding Procedure and Performance Qualification, as a basis for welding procedure and welding performance qualifications. Exceptions as they relate to sanitary applications are included in this document. It should be noted that the terms “essential variable” and “nonessential variable” have been changed to “qualification variable” and “welding variable” to be consistent with AWS B2.1.

A vertical line in the margin indicates a revision from the previous 1999 edition.

Comments and suggestions for the improvement of this standard are welcome. They should be sent to the Secretary, AWS D18 Committee on Welding in Sanitary Applications, American Welding Society, 550 N.W. LeJeune Road, Miami, FL 33126.

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Table of Contents

Page No.

Dedication v

Personnel vii

Foreword ix

List of Figures xi

1. Scope 1

2. Normative References 1

3. Terms and Definitions 2

4. Qualification 3

   1. Procedure Qualification 3

   2. Performance Qualification 5

5. Fabrication 7

   1. Material Preparation 7

   2. Preconstruction Weld Samples (PWS) 7

6. Visual Examination Requirements 7

   1. Extent of Examination 7

   2. Visual Examination Acceptance Criteria 8

7. Documentation 8

Annex A (Informative)—Guidelines for the Preparation of Technical Inquiries 11

Annex B (Informative)—Documentation Sample Forms 13

List of AWS Documents on Welding in Sanitary Applications 21

List of Figures

Figure Page No.

1. Examples of Maximum Allowable Discontinuities 9

2. Weld Discoloration Levels on Inside of Austenitic Stainless Steel Tube 10

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Specification for Welding of Austenitic Stainless Steel Tube and Pipe Systems in Sanitary (Hygienic) Applications

1. Scope

   This specification covers the requirements for Gas Tungsten Arc Welding and Plasma Arc Welding of stainless steels and nickel alloy tube and pipe 1/4 in [6 mm] diameter and larger in the fabrication and construction of new sanitary (hygienic) processing systems. This specification includes the welding of tube and pipe for the transportation of sanitary (hygienic) system products and cleaning or sanitizing solutions. It includes manual welding as well as automatic or mechanized welding, such as orbital welding. This specification addresses welding qualification and visual examination requirements for as-welded surfaces as well as finished surfaces.

   This specification is intended for new construction. However, the requirements may also be applied to maintenance and repair of food processing equipment. When there is a conflict between this specification and a design specification to which the equipment is being constructed, the applicable code shall govern on issues that apply to structural design or structural integrity. This specification does not address requirements designed to prevent corrosion damage during ser- vice or any structural design or integrity aspects of components or systems used for sanitary (hygienic) applications.

   Sanitary processing systems are intended to include those systems handling products for human and animal con- sumption, or for cleaning and sanitizing solutions used in these systems. Such products include dairy, meat, poultry, vegetables, beverages, personal care items (such as shampoo, soap, toothpaste, cosmetics), and other products consumed or used by humans or animals, which require freedom from contamination.

   When this specification is stipulated in contract documents, conformance with all provisions of this specification are required, except for those provisions that the Owner, their representative, or contract documents specifically modifies or exempts. The Owner or their representatives shall provide a complete specification for the piping or tubing system.

   This specification 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 or figures. The measurements may not be exact equiva- lents; therefore, each system must be used independently.

   Safety and health issues are beyond the scope of this standard, and therefore are not fully addressed herein. Safety and health information is available from other sources, including, but not limited to federal, state, and local regulations as well as other safety standards such as ANSI Z49.1, Safety in Welding, Cutting, and Allied Processes.

   
   

2. Normative References

The following standards contain provisions which, through reference in this text, constitute mandatory provisions of this AWS standard. For undated references, the latest edition of the referenced standard shall apply. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply.

AWS Standards1:

AWS A3.0, Standard Welding Terms and Definitions;

1 AWS standards are published by the American Welding Society, 550 N.W. LeJeune Road, Miami, FL 33126.