Field Welding Of Steel Water Pipe: Awwa Standard

ANSI/AWWA C206-17 (Revision of ANSI/AWWA C206-11)

®

AWWA Standard

Field Welding of Steel Water Pipe

Effective date: April 1, 2017. First edition approved by AWWA Board of Directors Jan. 10, 1946. This edition approved Jan. 14, 2017. Approved by American National Standards Institute Nov. 1, 2016.

SM

Copyright © 2017 American Water Works Association. All Rights Reserved.

AWWA Standard This document is an American Water Works Association (AWWA) standard. It is not a specification. AWWA standards describe minimum requirements and do not contain all of the engineering and administrative information normally contained in specifications. The AWWA standards usually contain options that must be evaluated by the user of the standard. Until each optional feature is specified by the user, the product or service is not fully defined. AWWA publication of a standard does not constitute endorsement of any product or product type, nor does AWWA test, certify, or approve any product. The use of AWWA standards is entirely voluntary. This standard does not supersede or take precedence over or displace any applicable law, regulation, or code of any governmental authority. AWWA standards are intended to represent a consensus of the water industry that the product described will provide satisfactory service. When AWWA revises or withdraws this standard, an official notice of action will be placed on the first page of the Official Notice section of Journal – American Water Works Association. The action becomes effective on the first day of the month following the month of Journal – American Water Works Association publication of the official notice.

American National Standard An American National Standard implies a consensus of those substantially concerned with its scope and provisions. An American National Standard is intended as a guide to aid the manufacturer, the consumer, and the general public. The existence of an American National Standard does not in any respect preclude anyone, whether that person has approved the standard or not, from manufacturing, marketing, purchasing, or using products, processes, or procedures not conforming to the standard. American National Standards are subject to periodic review, and users are cautioned to obtain the latest editions. Producers of goods made in conformity with an American National Standard are encouraged to state on their own responsibility in advertising and promotional materials or on tags or labels that the goods are produced in conformity with particular American National Standards. C aution Notice: The American National Standards Institute (ANSI) approval date on the front cover of this standard indicates completion of the ANSI approval process. This American National Standard may be revised or withdrawn at any time. ANSI procedures require that action be taken to reaffirm, revise, or withdraw this standard no later than five years from the date of publication. Purchasers of American National Standards may receive current information on all standards by calling or writing the American National Standards Institute, 25 West 43rd Street, Fourth Floor, New York, NY 10036; 212.642.4900; or emailing [email protected].

This AWWA content is the product of thousands of hours of work by your fellow water professionals. Revenue from the sales of this AWWA material supports ongoing product development. Unauthorized distribution, either electronic or photocopied, is illegal and hinders AWWA’s mission to support the water community.

ISBN-13, print:

978-1-62576-211-5

eISBN-13, electronic:

978-1-61300-410-4

DOI: http://dx.doi.org/10.12999/AWWA.C206.17

All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information or retrieval system, except in the form of brief excerpts or quotations for review purposes, without the written permission of the publisher. Copyright © 2017 by American Water Works Association Printed in USA

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Committee Personnel The task group for updating ANSI/AWWA C206 had the following personnel: Nash Williams, Chair S.A. Arnaout, Forterra, Dallas, Texas H. Bardakjian, Manufacturer’s Consultant, Glendale, Calif. J. Buratto, Lifelast Inc., Austin, Texas R.J. Card, Consultant, Sugarhill, Ga. D. Dechant, Manufacturer’s Consultant, Aurora, Colo. J. Forni, Jifco Inc., Livermore, Calif. B. Hansen, National Welding Corporation, Midvale, Utah B.D. Keil, Northwest Pipe Company, Draper, Utah J. Luka, American SpiralWeld Pipe Company, Columbia, S.C. R. Mielke, Northwest Pipe Company, Raleigh, N.C. J. Olmos, Ameron International, Rancho Cucamonga, Calif. G. Ruchti, Consultant, Punta Gorda, Fla. R.N. Satyarthi, Baker Coupling Company, Los Angeles, Calif. C. Shelley, Victaulic Company, Atlanta, Ga. B. Simpson, American SpiralWeld Pipe Company, Columbia, S.C. M.A. Vanderbosch, CAB Inc., Oakwood, Ga. N. Williams, National Welding Corporation, Midvale, Utah

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The AWWA Standards Committee on Steel Pipe, which reviewed and approved this standard, had the following personnel at the time of approval: John H. Bambei Jr., Chair Dennis Dechant, Vice-Chair John L. Luka, Secretary General Interest Members W.R. Brunzell, Brunzell Associates Ltd., Skokie, Ill. R.J. Card, Lockwood, Andrews & Newnam, Houston, Texas R.L. Coffey, HDR Engineering Inc., Omaha, Neb. S.N. Foellmi, Black & Veatch Corporation, Irvine, Calif. R.L. Gibson, Freese and Nichols Inc., Fort Worth, Texas iii Copyright © 2017 American Water Works Association. All Rights Reserved.

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M.D. Gossett,* HDR, Denver, Colo. M.B. Horsley,* Horsley Engineering LLC, Overland Park, Kan. R.A. Kufaas, Norske Corrosion & Inspection Services Ltd., Surrey, B.C., Canada J.L. Mattson, Corrosion Control Technologies, Sandy, Utah A. Murdock, CH2M HILL, Salt Lake City, Utah R. Ortega,* Consultant, Houston, Texas E.S. Ralph,† Standards Engineer Liaison, AWWA, Denver, Colo. A.E. Romer, AECOM, Orange, Calif. J.R. Snow, MWH Americas, Denver, Colo. W.R. Whidden, Woolpert, Winter Park, Fla.

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Producer Members D.W. Angell,† Standards Council Liaison, American Flow Control, Birmingham, Ala. S.A. Arnaout, Forterra, Grand Prairie, Texas H.H. Bardakjian, Consultant, Glendale, Calif. D. Dechant, Dechant Infrastructure Service, Aurora, Colo. V. DeGrande,* Ameron Water Transmission Group, Rancho Cucamonga, Calif. W.B. Geyer, Steel Plate Fabricators Association, Lake Zurich, Ill. B.D. Keil, Northwest Pipe Company, Draper, Utah J.L. Luka, American SpiralWeld Pipe Company, Columbia, S.C. R. Mielke,* Northwest Pipe Company, Raleigh, N.C. J. Olmos, Ameron Water Transmission Group, Rancho Cucamonga, Calif. G.F. Ruchti,* Consultant, Punta Gorda, Fla. B.P. Simpson,* American Cast Iron Pipe Company, Birmingham, Ala. C.C. Sundberg, Victaulic, Issaquah, Wash. D. Walker, Avid Protective Products LTD/Tnemec Company, Oakville, Ont., Canada J.A. Wise, Canus International Sales Inc., Surrey, B.C., Canada

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User Members G.A. Andersen, New York City Bureau of Water Supply, Little Neck, N.Y. J.H. Bambei Jr., Bambei Engineering Services, Arvada, Colo.

* Alternate † Liaison, nonvoting iv Copyright © 2017 American Water Works Association. All Rights Reserved.

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B. Cheng, Metro Vancouver, Burnaby, B.C., Canada M.E. Conner, San Diego County Water Authority, San Diego, Calif. R.V. Frisz, US Bureau of Reclamation, Denver, Colo. S. Hattan, Tarrant Regional Water District, Fort Worth, Texas P.K. Karna, Tacoma Water, Tacoma, Wash. T.J. Jordan,* Metropolitan Water District of Southern California, La Verne, Calif. M. McReynolds, Metropolitan Water District of Southern California, Oak Park, Calif. M. Turney,* Denver Water, Denver, Colo. N.A. Wigner, Los Angeles Department of Water and Power, Los Angeles, Calif.

* Alternate v Copyright © 2017 American Water Works Association. All Rights Reserved.

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Contents All AWWA standards follow the general format indicated subsequently. Some variations from this format may be found in a particular standard. SEC.

PAGE

SEC.

PAGE

Foreword I Introduction...................................... ix

4.2 General Requirements........................ 4 4.3

Joint Types......................................... 5

I.A Background....................................... ix

4.4

Qualification of Welding Procedures, Welders, and Welding Operators....................... 7

I.B History.............................................. ix I.C Acceptance......................................... x II

Special Issues..................................... xi

4.5

Welding Electrodes............................ 8

III

Use of This Standard......................... xi

4.6

Welding Procedure Details................. 8

III.A Purchaser Options and Alternatives................................. xi

4.7

Repair of Welds................................ 11

5 Verification

III.B Modification to Standard................. xii IV

5.1 Inspection........................................ 11

Major Revisions................................ xii

5.2 Testing............................................. 12 5.3 Rejection.......................................... 13

Standard 1 General

6 Delivery

1.1 Scope................................................. 1

6.1 Marking........................................... 14

1.2 Purpose.............................................. 2

6.2 Packaging and Shipping................... 14

1.3 Application......................................... 2

6.3

2 References......................................... 2

Figures 1 Fillet-Weld Size................................... 9

3 Definitions........................................ 3

2

4 Requirements 4.1 Materials............................................ 4

Affidavit of Compliance................... 15

Look-Box for Vacuum Testing of Circumferential Weld Seams......................................... 14

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Foreword This foreword is for information only and is not a part of ANSI*/AWWA C206. I. Introduction. I.A. Background.  The provisions of this standard describe the requirements for welding steel water pipe joints in water transmission and distribution lines. The purchaser for each project is responsible for determining if any unusual circumstances related to the project require additional provisions that are not included in the standard. The design of field-welded joints is not discussed in this standard. Useful information on this subject may be found in AWWA Manual M11, Steel Pipe—A Guide for Design and Installation,† and in Useful Information on the Design of Plate Structures (American Iron and Steel Institute‡). After the welded field joint has been completed, if the pipe has been coated or lined, the joint shall be coated and lined with a coating system compatible with that on the body of the pipe, in accordance with the requirements for field repairs stated in the appropriate AWWA coating or lining standard. For lap-welded pipe with an inside diameter equal to or exceeding 48 in. (1,200 mm) and where the purchaser deems single welding to be acceptable, inside welding is recommended. Safety precautions shall be utilized in all pipe sizes, although when pipe with inside diameters less than 48 in. (1,200 mm) down to 27 in. (675 mm) is welded from the inside, additional safety precautions shall be observed. Interior welding on pipe diameters less than 27 in. (675 mm) is not recommended. Pipe requiring inside welds with limited access should be supplied with 3-in. (75-mm) diameter weld lead pass holes at approximately 400-ft (122-m) centers to allow passage of welding leads to the joint location. Shorter distances between pass holes may be required, depending on actual project conditions. Pass holes in the pipe will permit shorter welding leads and thus avoid erratic voltage drops caused by excessively long welding leads. The pass hole is fabricated using a weldable-grade inside-threaded pipe half-coupling-welded to a hole cut through the pipe wall. After using the pass hole, a weldable-grade plug shall be threaded into the opening and seal-welded to secure.

* American National Standards Institute, 25 West 43rd Street, Fourth Floor, New York, NY 10036. † AWWA Manual M11. Steel Pipe—A Guide for Design and Installation. Denver, CO: AWWA . ‡ Useful Information on the Design of Plate Structures, Steel Plate Engineering Data, Vol. 2, American Iron and Steel Institute, 1101 17th Street, NW, Suite 1300, Washington, DC 20036. ix Copyright © 2017 American Water Works Association. All Rights Reserved.

I.B. History.  This standard was first approved as tentative by AWWA in January 1946 and by the American Welding Society (AWS) in October 1945. It was advanced to standard status by AWWA in 1950 and by AWS in 1951. The joint AWWAAWS activity continued through revisions in 1957 (AWWA C206-57, AWS D7.0-57) and 1962 (AWWA C206-62, AWS D7.0-62a). The joint committee was dissolved in 1971, and the standard was assigned to the AWWA Standards Committee on Steel Pipe. Subsequent editions of the standard were published in 1975, 1982, 1988, 1991, 1997, 2003, and 2011. This edition was approved by the AWWA Board of Directors on Jan. 14, 2017. I.C. Acceptance.  In May 1985, the US Environmental Protection Agency (USEPA) entered into a cooperative agreement with a consortium led by NSF International (NSF*) to develop voluntary third-party consensus standards and a certification program for direct and indirect drinking water additives. Other members of the original consortium included the Water Research Foundation (formerly AwwaRF†) and the Conference of State Health and Environmental Managers (COSHEM). The American Water Works Association (AWWA) and the Association of State Drinking Water Administrators (ASDWA) joined later. In the United States, authority to regulate products for use in, or in contact with, drinking water rests with individual states.‡ Local agencies may choose to impose requirements more stringent than those required by the state. To evaluate the health effects of products and drinking water additives from such products, state and local agencies may use various references, including 1. Specific policies of the state or local agency. 2. Two standards developed under the direction of NSF: NSF/ANSI 60, Drinking Water Treatment Chemicals—Health Effects, and NSF/ANSI 61, Drinking Water System Components—Health Effects. 3. Other references, including AWWA standards, Food Chemicals Codex, Water Chemicals Codex,§ and other standards considered appropriate by the state or local agency. Various certification organizations may be involved in certifying products in accordance with NSF/ANSI 61. Individual states or local agencies have authority to accept

* NSF International, 789 North Dixboro Road, Ann Arbor, MI 48105. † Water Research Foundation, 6666 West Quincy Avenue, Denver, CO 80235. ‡ Persons outside the United States should contact the appropriate authority having jurisdiction. § Both publications available from National Academy of Sciences, 500 Fifth Street, NW, Washington, DC 20418. x Copyright © 2017 American Water Works Association. All Rights Reserved.

or accredit certification organizations within their jurisdictions. Accreditation of certification organizations may vary from jurisdiction to jurisdiction. Annex A, “Toxicology Review and Evaluation Procedures,” to NSF/ANSI 61 does not stipulate a maximum allowable level (MAL) of a contaminant for substances not regulated by a USEPA final maximum contaminant level (MCL). The MALs of an unspecified list of “unregulated contaminants” are based on toxicity testing guidelines (noncarcinogens) and risk characterization methodology (carcinogens). Use of Annex A procedures may not always be identical, depending on the certifier. ANSI/AWWA C206 does not address additives requirements. Users of this standard should consult the appropriate state or local agency having jurisdiction in order to 1. Determine additives requirements, including applicable standards. 2. Determine the status of certifications by parties offering to certify products for contact with, or treatment of, drinking water. 3. Determine current information on product certification. II. Special Issues.  This standard has no applicable information for this section. III. Use of This Standard.  It is the responsibility of the user of an AWWA standard to determine that the products described in that standard are suitable for use in the particular application being considered. III.A. Purchaser Options and Alternatives.  The following information should be provided by the purchaser. 1. Standard used—that is, ANSI/AWWA C206, Field Welding of Steel Water Pipe, of latest revision. 2. Whether compliance with NSF/ANSI 61, Drinking Water Treatment Chemicals—Health Effects, is required. 3. Details of other federal, state or provincial, and local requirements (Sec. 4.1.1). 4. Provisions for alleviation of thermal stresses (Sec. 4.2.6). 5. Type of joint (Sec. 4.3). 6. Lap joint (Sec. 4.3.2). 7. Butt joint (Sec. 4.3.3). 8. Option regarding backing rings (Sec. 4.3.3.1). 9. Seal weld of butt straps to facilitate an air test (Sec. 4.3.4). 10. Notch tough weld criteria, if required, temperature of test, and test values (Sec. 4.6.10). 11. Weld inspection, if required (Sec. 5.1.3). 12. Testing methods, if required (Sec. 5.2).

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13. Nondestructive testing of welded joints if substituted for hydrostatic tests (Sec. 5.2.2). 14. Affidavit of compliance (Sec. 6.3). III.B. Modification to Standard.  Any modification of the provisions, definitions, or terminology in this standard must be provided by the purchaser. IV. Major Revisions.  Major changes made to the standard in this revision include the following: 1. Some additional wording was added in Sec. 1.1, Scope, to clarify the role of AWS D1.1 as the supporting document to the standard. 2. The definitions of CJP and WPS were revised to be consistent with the supporting documents (Section 3). 3. Sec. 4.2.6, Thermal-Stress Control, was revised, including adding a sentence on weld-after-backfill. 4. Sec. 4.3.3, Butt Joints, was revised to provide additional explanation for the three types of groove welds. 5. Section 4.6.2, Preparation of Welding Surfaces, was revised adding clarification that coatings or primers must be removed before welding. 6. Section 4.6.3, Lap-Joint Assembly, was revised clarifying the fillet-weld geometry and adding a new Figure 1. 7. Section 5.2.2.1, Testing Field-Butt Joints With or Without Backing Rings, was revised to add a note clarifying that radiographic testing should not be used for butt joints with steel backing. V. Comments.  If you have any comments or questions about this standard, please call AWWA Engineering and Technical Services at 303.794.7711, FAX at 303.795.7603; write to the department at 6666 West Quincy Avenue, Denver, CO 80235-3098; or email at [email protected].

xii Copyright © 2017 American Water Works Association. All Rights Reserved.

ANSI/AWWA C206-17 (Revision of ANSI/AWWA C206-11)

®

AWWA Standard

Field Welding of Steel Water Pipe SECTION 1: Sec. 1.1

GENERAL

Scope This standard describes manual, semiautomatic, and automatic field welding by the metal arc-welding processes for steel water pipe manufactured in accordance with ANSI*/AWWA C200, Steel Water Pipe—6 In. (150 mm) and Larger. This standard describes field-performed full circumferential welding of three types of pipe joints: (1) lap joints, (2) butt joints, and (3) butt-strap joints. This standard also applies to other welding required in field fabrication and installation of specials and appurtenances. However, when possible, pipe fabrications and fittings should be performed by the manufacturer at a manufacturing facility. The design of field-welded joints is not covered within this standard. This standard recognizes AWS† D1.1 as the supporting document. AWWA C206 references subclauses within the AWS D1.1 clauses (previously referred to as sections) on Prequalification, Qualification, Fabrication, and Inspection. When AWWA C206 is silent regarding a requirement listed in AWS D1.1, such requirement is not required in AWWA C206. Although AWS D1.1 supports AWWA C206 in many sections, when there is a conflict between these documents then AWWA C206 shall govern.

* American National Standards Institute, 25 West 43rd Street, Fourth Floor, New York, NY 10036. † American Welding Society, 550 Northwest LeJuene Road, Miami, FL 33126. 1 Copyright © 2017 American Water Works Association. All Rights Reserved.

2 AWWA C206-17

Welding of gasketed joints may require modification to the parameters of this welding standard.

Sec. 1.2

Purpose The purpose of this standard is to provide minimum requirements for field welding and inspection of steel water pipe.

Sec. 1.3

Application This standard can be referenced in documents for field welding of steel water pipe. The stipulations of this standard apply when this document has been referenced and then only to field welding of steel water pipe.

SECTION 2:

REFERENCES

This standard references the following documents. In their latest editions, they form a part of this standard to the extent specified within the standard. In any case of conflict, the requirements of this standard shall prevail. ANSI/AWWA C200—Steel Water Pipe—6 In. (150 mm) and Larger. ANSI/AWWA C205—Cement–Mortar Protective Lining and Coating for Steel Water Pipe—4 In. (100 mm) and Larger—Shop Applied. ANSI/AWWA C206—Field Welding of Steel Water Pipe. ANSI/AWWA C209 – Cold-Applied Tape Coatings for Steel Water Pipe, Special Sections, Connections, and Fittings ANSI/AWWA C214—Tape Coatings for Steel Water Pipe. ANSI/AWWA C215—Extruded Polyolefin Coatings for Steel Water Pipe. ANSI/AWWA C216—Heat-Shrinkable Cross-Linked Polyolefin Coatings for Steel Water Pipe and Fittings. ASME* Boiler and Pressure Vessel Code (BPVC)—Section VIII, Division 1, Rules for Construction of Pressure Vessels. ASTM† A370—Standard Test Methods and Definitions for Mechanical Testing of Steel Products. AWS A2.4—Standard Symbols for Welding, Brazing, and Nondestructive Examination.

* ASME International, 3 Park Avenue, New York, NY 10016. † ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428.

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Field Welding Of Steel Water Pipe 3

AWS A3.0—Standard Welding Terms and Definitions Including Terms for Adhesive Bonding, Brazing, Soldering, Thermal Cutting , and Thermal Spraying. AWS D1.1—Structural Welding Code—Steel. AWWA M11—Steel Pipe—A Guide for Design and Installation.

SECTION 3:

DEFINITIONS

The following definitions shall apply in this standard: 1.  CJP:  Complete joint penetration as defined in AWS A3.0. 2.  Constructor:  The party that provides the work and materials for placement or installation. 3.  CWI:  Certified welding inspector. 4.  Faying surfaces:  The mating surface of a member that is in contact with, or in close proximity to, another member to which it is to be joined. 5.  Full-fillet weld:  A fillet weld with both legs of the weld equal in size to the thickness of the thinner member joined. 6.  Manufacturer:  The party that manufactures, fabricates, or produces materials or products. 7.  NDT:  Nondestructive testing. 8.  PQR:  Procedure qualification record. A record of welding variables used to produce an acceptable test weldment and the results of the tests conducted on the weldment to qualify a welding procedure specification. 9.  Purchaser:  The person, company, or organization that purchases any materials or work to be performed. 10.  WPS:  Welding procedure specification. A document providing the required welding variables for a specific application to ensure repeatability by properly trained welders and welding operators. 11.  WQR:  Welder qualification record. The document to describe the welder testing and results of that testing that allows certification of a welder to perform welding. 12.  Weld-after-backfill:  The sequence of assembling a lap-welded joint, welding the outside weld (if required), applying the external joint pipe coating system, backfilling the pipe, and then welding the inside joint at a later time (where inside welding is safe and practical). 13.  Welder or welding operator:  A person who performs a manual, semi­ automatic, or automatic welding operation. Copyright © 2017 American Water Works Association. All Rights Reserved.

4 AWWA C206-17

14.  Welding symbols:  Symbols used on documents to define weld type, size, location, and geometry. 15.  Welding terms:  Welding terms shall be interpreted in accordance with the definitions given in AWS A3.0, supplemented by terminologies identified in AWS D1.1.

SECTION 4: Sec. 4.1

REQUIREMENTS

Materials 4.1.1  General.  Material provided and work completed shall meet the requirements of this standard. Materials shall comply with the requirements of the Safe Drinking Water Act and other federal regulations for potable water, wastewater, and reclaimed water systems as applicable.

Sec. 4.2

General Requirements 4.2.1  Construction drawings.  Construction drawings shall be the purchaser’s drawings or approved constructor’s drawings. 4.2.2  Equipment.  The constructor’s equipment for welding shall be designed and maintained in such condition as to permit qualified welding operators to follow the welding procedure details (Sec. 4.6) and obtain the results prescribed. 4.2.3  Welding process.  Welding shall be performed by any welding process that will (1) produce a joint meeting the minimum strength requirements of the base metals and (2) meet the welding procedure qualification required in Sec. 4.4 of this standard, except that the short-circuiting transfer mode of the gas metal arc-welding process shall not be used for weld sizes greater than 3/16 in. (4.8 mm).* 4.2.4  Safety and environmental considerations.  Welding, cutting, and grinding operations will produce smoke and fumes. In confined spaces, the constructor may be required to utilize exhaust ventilation systems, employ air-monitoring equipment, and take other actions to ensure meeting safety regulations. Interior pipe welding shall only be performed after safe and adequate access and egress are provided for the personnel. Federal, state or provincial, and local regulations shall also be followed.

* Metric conversions given in this standard are direct conversions of US customary units and are not those specified in International Organization for Standardization (ISO) standards.

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Field Welding Of Steel Water Pipe 5

4.2.5  Pipe condition.  Prior to welding, ends of pipe to be welded shall be in conformance with the requirements for end preparation for field joints in accordance with ANSI/AWWA C200. Any linings or coatings shall be held back in an amount that is appropriate for the type of joint. 4.2.6  Thermal-stress control.  For welded joint pipelines, variations in pipe temperature at the time of installation and the temperature difference between the pipeline and the temperature of the fluid being transported during operation may induce thermal stresses. Anticipated thermal stresses should be evaluated by the purchaser. Various methods are available to reduce thermal stresses, such as shading the pipe in the trench, using backfill as insulation, making certain joint welds (particularly when closure joints are made) at a time of day when the temperature is the lowest, or a combination of these methods. The weld-after-backfill process can eliminate thermal control joints if the pipeline is allowed to reach thermal equilibrium with the backfill prior to welding. In exposed applications, couplings or expansion joints may be used to control thermal stresses as long as the movement in each joint is less than the maximum allowed by the applicable AWWA standard or as recommended by the coupling manufacturer.

Sec. 4.3

Joint Types 4.3.1  General.  Joints shall be lap joints, butt joints, or butt-strap joints, as specified by the purchaser. 4.3.2  Lap joints.  Lap joints shall be full-fillet single-welded unless otherwise specified by the purchaser. Field joints shall be assembled so that seams in adjacent pipe sections are offset from each other by at least five times the thickness of the thinner of the pipes being joined. 4.3.2.1  Single-welded lap joints.  At the option of the constructor and subject to the purchaser’s approval, single-welded lap joints may be welded from either the outside of the pipe or from the inside of the pipe if the diameter is large enough. 4.3.2.2  Double-welded lap joints.  If specified by the purchaser, doublewelded lap joints (welded inside and outside) shall be required. 4.3.2.3  Single-welded lap joints with air testing.  If specified by the purchaser, single-welded lap joints with air testing shall be completed by the addition of a second weld to facilitate the air test described in Sec. 5.2.2.2. This second weld shall only be a seal weld. Copyright © 2017 American Water Works Association. All Rights Reserved.

6 AWWA C206-17

4.3.3  Butt joints.  Butt joints shall be a groove weld with backing (root not back-gouged), groove weld without backing (root back-gouged), or groove weld without backing (root not back-gouged) at the option of the purchaser, and shall be complete joint penetration (CJP) welds. Field joints shall be assembled so that seams in adjacent pipe sections are offset from each other by at least five times the thickness of the thinner of the pipes being joined. As noted in AWS D1.1 for CJP groove welds, single side welding without backing or back gouging is not prequalified. 4.3.3.1  Single-groove butt joints.  At the option of the purchaser, singlegroove butt joints may be welded from the outside of the pipe or from inside the pipe if the diameter is large enough. Backing rings will assist in proper alignment and may be used unless otherwise prohibited. The exterior backing ring should remain after welding unless otherwise required. The interior backing ring may remain after welding, subject to evaluation of possible interference with the interior lining, with agreement of the purchaser. Depending on the welding process used, the butt joint without a backing ring may require back grinding or back gouging, then back welding on the opposite side of the bevel to achieve a CJP butt joint. Back grinding or gouging ensures complete removal of embedded slag. 4.3.4  Butt-strap joints.  Butt straps shall receive complete circumferential single-welded full-fillet welds, either on the inside or outside of the butt strap. If specified by the purchaser, a double-welded butt strap with full-fillet welds shall include welding both the inside and outside of the butt strap. Butt straps may be shop-attached by welding to one pipe end or shipped loose for field attachment and welding. The butt straps shall have a minimum plate thickness equal to the thinnest member being joined and shall be fabricated from material of equivalent minimum physical properties of the thinnest member and compatible chemical properties of both members being joined. Strap width shall be not less than 4 in. (102 mm) for pipe less than 36 in. (900 mm) in nominal diameter and 6 in. (152 mm) for pipe 36 in. (900 mm) in nominal diameter and larger. The minimum lap between pipe ends and the edge of the butt strap shall be 1 in. (25 mm) for pipe less than 36 in. (900 mm) in nominal diameter and 2 in. (51 mm) for pipe 36 in. (900 mm) in nominal diameter and larger. Longitudinal seams of butt straps shall be joined by CJP welded butt joints. See AWS D1.1 for various joint details. For butt-strap joints, the seams of adjacent pipe sections may be in alignment, provided the butt-strap seams are offset from the pipe seams by at least five times the thickness of the thinner member involved in the joint. At the option of the constructor and subject to the purchaser’s approval, the butt strap may be welded

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Field Welding Of Steel Water Pipe 7

from the outside of the pipe or from inside the pipe if the diameter is large enough. With the purchaser’s approval, either the inside or the outside weld may be a seal weld to facilitate an air test as described in Sec. 5.2.2.2 if the other weld provides sufficient strength to carry all loads anticipated at the joint.

Sec. 4.4

Qualification of Welding Procedures, Welders, and Welding Operators 4.4.1  General.  Joint-welding procedures to be used for work under the provisions of this standard and welders, welding operators, and tack welders shall be qualified by tests, except procedures that comply with Sec. 4.4.2. General requirements for qualification shall be in accordance with AWS D1.1, Qualification clause. (Note: A pipeline is not “tubular construction” as defined in AWS D1.1.) Written procedures shall be prepared by the constructor and shall be made available to the welders at the jobsite and to those authorized to examine the welds. 4.4.2  Procedure qualification record (PQR).  The PQR document provides the verification that the welding method and operating values provide the required metallurgical and mechanical characteristics. 4.4.3  Welding procedure specification (WPS).  The WPS will provide the operating ranges (voltage, amperage, travel speed, etc.) allowed during the actual welding operations. Certain joint-welding procedures, as outlined in AWS D1.1, Prequalification of Welding Procedure Specifications clause, are prequalified and are exempt from tests by following AWS D1.1 requirements. Other procedures shall be qualified in accordance with AWS D1.1.* 4.4.4  Welder, welding-operator, and tack welder qualification.  Welders and welding operators shall be qualified by tests as prescribed in AWS D1.1.† The welder qualification record (WQR) provides certification that the welder, welding operator, or tack welder is qualified to perform welding under this standard. The welder and welding operator qualification will remain in effect indefinitely unless (1) the welder is not engaged in a given process of welding for which the welder or welding operator is qualified for a period exceeding six months or unless (2) there is some specific reason to question a welder’s or welding operator’s ability. A tack welder who passes the tests as prescribed in AWS D1.1 shall be considered eligible to perform tack welding indefinitely in the positions and with the

* AWS D1.1, Table 4.7, refers to qualification of welding procedures with a base metal included in group I and group II of Table 3.1 in AWS D1.1. For the purposes of AWWA C206, group I and group II materials shall also include pipe produced using any steel or pipe listed in AWWA C200. † AWS D1.1, Clause 3.3, states base metal and filler metals listed in Table 3.1 may be used in prequalified welding procedure specification (WPS) as described in AWS D.1.1.

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8 AWWA C206-17

process for which the tack welder is qualified unless there is some specific reason to question the tack welder’s ability. 4.4.4.1  Records.  Records of the test results shall be kept by the constructor and shall be available to the purchaser.

Sec. 4.5

Welding Electrodes 4.5.1  General.  Welding electrodes shall be the same classification as those used for the welding-procedure qualification in Sec. 4.4.2. When low-hydrogen electrodes are used for welding, the constructor shall control the storage and handling of electrodes to maintain the low-hydrogen characteristics as recommended by the electrode manufacturer.

Sec. 4.6

Welding Procedure Details 4.6.1  General.  Welds in the pipe and the attachments shall be performed in strict accordance with the qualification procedures stated in Sec. 4.4. Weld symbols shall be as defined under AWS A2.4. Special welding conditions shall be fully explained by added notes or details. 4.6.2  Preparation of welding surfaces.  Surfaces to be welded shall be free from moisture, scale, slag, heavy rust, grease, coatings, paint, primer, cement, or any other foreign material. Joint surfaces shall be smooth, uniform, and free from defects that adversely affect proper welding. After wire brushing, any residual light film of rust remaining on the cut or sheared edges to be welded need not be removed. Surfaces that were previously thermal cut (torch cut) or gouged shall be ground to remove slag and oxidation. Factory-applied coatings or primers shall be removed from pipe ends prior to engaging the two pipe ends where the engagement of the bell and spigot will not allow cleaning after engagement. Coatings or primers even when advertised as “weldable” are not allowed to remain on the pipe ends. 4.6.3  Lap-joint assembly.  Clearance between faying surfaces of lap joints shall not exceed 1/8 in. (3.2 mm) at any location for fillet welds on pipe having wall thicknesses less than or equal to 5/16 in. (7.9 mm), and clearance between faying surfaces of lap joints shall not exceed 3/16 in. (4.8 mm) at any location for fillet welds on pipe having wall thicknesses greater than 5/16 in. (7.9 mm). In the event that the faying surfaces exceed these tolerances, verify if the pipe ends comply with the required manufacturing tolerances; if so, the constructor shall fit the area to within the tolerances stated in this section. The minimum overlap of the assembled bell-and-spigot sections of the joint shall be 1 in. (25 mm) or three times the thickness of the belled

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Field Welding Of Steel Water Pipe 9

Leg “A”

Fillet Weld Face

Leg “B” Note: Leg “B” shall be ≥ Leg “A”

Figure 1  Fillet-weld size pipe, whichever is greater. No part of any field weld shall be closer than 1 in. (25 mm) to the nearest point of tangency to a bell radius. Joint fabrication tolerances shall be in accordance with ANSI/AWWA C200. The fillet-weld Leg A size shall be the specified thickness plus the root opening between the two overlapping plates. Leg B shall be of equal or greater length than Leg A , subject to the allowances in AWS D1.1, Visual Inspection Acceptance Criteria for Statically Loaded Nontubular Connections clause (See Figure 1). In the event a fillet weld connects two members having different wall thicknesses, the allowable gap will be governed by the Leg A wall thickness. 4.6.4  Weld-after-backfill sequence.  Welding inside field joints after backfill is an acceptable practice under this standard, provided the requirements of ANSI/AWWA C205, C206, C209, C214, C215, C216, and other applicable AWWA standards are followed. Consult with the manufacturers subject to the above-referenced standards regarding recommended products, installation, and backfill procedures required for the weld-after-backfill sequence. At the request of the purchaser, the manufacturer shall provide testing or historical information to verify that the exterior joint coating will comply with the applicable material standard and the coating manufacturer’s requirements after completion of the welding. Note: In all cases, the exterior coating manufacturer should be consulted to verify its product is intended for the weld-after-backfill application with the project-specific conditions. The constructor shall adhere strictly to the specified stab depth minimum and joint gap tolerances.

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10 AWWA C206-17

4.6.5  Weather conditions.  Welding shall not be performed when the ambient temperature is less than 0°F (–18°C) or when surfaces are wet from rain, condensation, snow, or ice, or during periods of high wind, unless the work is properly protected. Regardless of the ambient conditions, the metal temperature in the pipe wall shall not be less than 32°F (0°C) at any point within 3 in. (76 mm) of the point of welding or four times the pipe wall thickness, whichever is greater. 4.6.6  Preheating.  Preheating of the joints to be welded shall be performed in accordance with AWS D1.1, Prequalified Minimum Preheat and Interpass Temperature clause. When preheating is required, it shall extend ahead of the point of welding a minimum distance of four times the plate thickness and not less than 3 in. (76 mm) on each side of the seam. Proper preheat temperature shall be determined periodically during welding by checking the material at a point at least four times the plate thickness and not less than 3 in. (76 mm) on either side of the seam. 4.6.7  Tack welding.  Small erection tack welds used in the assembly of joints need not be removed provided (1) they are sound and their size does not exceed the subsequently applied root pass; (2) they do not interfere with welding procedures required for closure joints to control thermal stresses (Sec. 4.2.6); (3) they do not prevent the proper distribution of the annular space to control the distance between faying surfaces in lap joints (Sec. 4.6.3); (4) the electrodes used in making the tack welds shall be the same as used in the final welds; and (5) welding is performed in strict accordance with the qualification procedures stated in Sec. 4.4. 4.6.8  Weld appearance and weld contour.  The welds shall be applied using continuous stringer beads or a weave pattern meeting AWS D1.1. Each bead shall be cleaned and descaled before the succeeding bead is applied. Welded joints shall not be covered or coated until after welding is completed and the weld accepted. 4.6.8.1  Surface pass.  The surface pass on welds shall be central to the seam, and all surface passes shall be smooth and free from depression. The final weld surface shall be free from weld slag and porosity. 4.6.8.2  Undercutting, overlapping, and finished fillet weld.  Undercutting of the base metal in pipe and adjoining the weld, which exceeds AWS D1.1 requirements, is a defect and shall be repaired. Burning back the inside or outside corner during application of a fillet weld shall be permitted if the edge can be clearly defined. The finished fillet weld shall be free of grooves, deep valleys, or ridges and shall contain no abrupt changes in the section at the toe. 4.6.8.3  Lap-weld or fillet-weld face.  The face of fillet welds shall be flat to slightly convex; see Figure 1.

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Field Welding Of Steel Water Pipe 11

4.6.8.4  Weld defects.  Cracks in welds and base metal, incomplete fusion, lack of complete joint penetration (including fillet welds that do not penetrate past the point of intersection of the members being joined), and weld overlap are unacceptable. Pinholes and porosity are unacceptable and shall be repaired according to Sec. 4.7. Arc strikes outside the weld boundary are unacceptable and shall be ground flush with the base metal and shall be repaired according to Sec. 4.7 if additional weld metal is required. 4.6.9  Matching butt joints.  Butt joints shall be accurately aligned and retained in position during the welding operation so that in the finished joint the abutting pipe sections shall not be misaligned by more than 20 percent of the pipe wall thickness or a maximum of 1/8 in. (3.2 mm), whichever is less. 4.6.10  Notch tough welds.  When required for the pipe material or requested by the purchaser, welding procedures shall be qualified to provide notch tough welds. Filler material shall meet the same toughness requirements as the base metal or as required by the purchaser’s documents. If not otherwise specified, the minimum average value of absorbed energy shall be 20 ft-lb (33.9 N-m) at 32°F (0°C) or the lowest anticipated service temperature, whichever is lower. Charpy V-notch (CVN) transverse specimens shall be prepared in accordance with the requirements of ASTM A370 and AWS D1.1, Clause 4, Part D, Requirements for CVN Testing.

Sec. 4.7

Repair of Welds 4.7.1  Repair of defective welds.  Welds that are defective shall be repaired to meet the requirements of Sec. 4.5 and 4.6. 4.7.1.1  Defects in welds.  Defects in welds or defective welds shall be removed and that section of the joint shall then be rewelded. The amount of material removed shall be limited to that required to correct the defect. After the repair is made, the joint shall be checked by repeating the original test procedure utilized to locate the defect.

SECTION 5: Sec. 5.1

VERIFICATION

Inspection Inspection or a lack of inspection shall not relieve the constructor of the responsibility for performing work in accordance with this standard. The constructor

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12 AWWA C206-17

shall notify the purchaser before performing any work under the provisions of this standard so that the purchaser can prepare for the inspection. 5.1.1  Access.  The purchaser shall have free access to those areas of the project that are involved with the performance of any work pertaining to this standard. 5.1.2  Facilities.  The constructor shall provide the purchaser with reasonable facilities and space for inspection, testing, and obtaining the information required to determine the character of materials used, the progress and conditions of the work, and the results obtained. 5.1.3  Weld inspection.  When requested by the purchaser, a full-time welding inspector shall be present whenever there is welding to be performed. The welding inspector shall have prior pipe-welding inspection experience and shall be a certified welding inspector (CWI) in accordance with the provisions of AWS D1.1. 5.1.4  Visual inspection.  Field welds shall be visually inspected by an individual who by training, experience, or both, in metals fabrication, inspection, and testing is competent to perform the visual inspection. Any of the weld defects identified by visual inspection shall be cause for rejection, and the deficient weld shall be repaired or replaced. The acceptance criteria for field welds shall meet the requirements of AWS D1.1, Visual Inspection Acceptance Criteria for Statically Loaded Nontubular Connections clause, except as modified in Sec. 4.6.8.

Sec. 5.2

Testing Inspection and testing for weld integrity shall be performed unless otherwise specified by the purchaser. All welds shall be visually inspected in accordance with Sec. 5.1.4. 5.2.1  Hydrostatic test.  Tests for leaks in all types of welded joint pipelines shall be made by hydrostatically testing the entire pipeline, unless the procedures, frequency of tests, and standards for acceptance or rejection of an alternative nondestructive method are approved by the purchaser. If leakage exceeds the amount allowed in the purchaser’s documents, the leaks shall be located and repaired in accordance with Sec. 4.7. 5.2.2  Alternative tests.  In lieu of the hydrostatic test, the purchaser may approve nondestructive testing (NDT) of welded joints. 5.2.2.1  Testing field-butt joints with or without backing rings.  Field-butt joints with or without a backing ring may be tested by 100 percent magnetic particle testing using acceptance criteria as stated in AWS D1.1 or 100 percent ultrasonic

Copyright © 2017 American Water Works Association. All Rights Reserved.

Field Welding Of Steel Water Pipe 13

testing of 10 percent of the joints, using methods and acceptance criteria in ASME BPVC, Section VIII, Division 1. Note: Radiographic testing of butt joints with steel backing shall not be utilized because of the difficulty inherent in interpreting the results. 5.2.2.2  Testing field fillet-weld joints.  Field fillet-weld joints used for single-welded lap joints, double-welded lap joints, and butt-strap joints may be tested using magnetic particle testing procedures and acceptance criteria as stated in AWS D1.1. Magnetic particle testing is not required for a seal weld used to facilitate air-tested joints unless the seal weld is a structural element of the joint. Double-welded lap joints can also be tested by shop drilling and tapping a ¼-in. (6.4-mm) national pipe thread hole into the spigot or bell end of the pipe. Apply approximately 40 psi (276 kPa) of air, or other satisfactory gas, into the annular space between the two fillet welds and maintain for a period of 5 minutes. If the pressure remains at 40 psi (276 kPa), the test is considered passed. If the test pressure drops below 40 psi (276 kPa), maintain the pressure at 40 psi (276 kPa) from an external source and paint the welds with a soap solution. Mark any leaks indicated by the escaping gas bubbles and repair leak indications per Sec. 4.7. After successfully passing the test, close the threaded openings with pipe plugs or by welding. Note: Radiographic or ultrasonic testing of lap joints shall not be utilized because of the difficulty inherent in interpreting the results. 5.2.2.3  Vacuum box test.  Both butt-joint welds and fillet welds may be tested using a vacuum box. In this test, the weld is painted with a soap solution, a clear plastic box with a foam perimeter is placed over the test section, and a vacuum is induced in the box (see Figure 2). Mark any leaks indicated by the escaping gas bubbles and repair according to Sec. 4.7.1. This test method may require additional hold-back for coatings and linings to allow a proper seal. Note: Vacuum boxes have been traditionally constructed of a sealed clear plastic cover with an open bottom. The open bottom is sealed against the pipe surface by a closed-cell foam rubber gasket. Vacuum gauges, valves, and vacuum pump or air ejector are attached. The gauge should register a partial vacuum of at least 10 in. (250 mm) of mercury when testing the weld seam.

Sec. 5.3

Rejection Any work that is not in accordance with the requirements of this standard shall be rejected. The constructor has the option of either repairing an unacceptable weld or removing and replacing the defective weld. Copyright © 2017 American Water Works Association. All Rights Reserved.

14 AWWA C206-17

Acrylic Cover

R

Sponge Rubber Gasket

Section

Pipe Wall 2-Way Valve

Vacuum Gauge

Air Ejector

Butt-Welded Circumferential Joint

Hose to Compressor Plan

Figure 2  Look-box for vacuum testing of circumferential weld seams

SECTION 6: Sec. 6.1

DELIVERY

Marking When required by the purchaser, pipe, fittings, and pipe specials shall have a serial number or other identification mark that will reference the line diagram or laying schedule. The welding operator and the subsequent inspections performed on each joint shall reference these serial numbers or other identification numbers to document these tasks. 6.1.1  Exterior.  The serial number or other identification mark shall be painted in a conspicuous location on the exterior of each section of pipe, fitting, or pipe special. 6.1.2  Interior.  When joints require interior field welds, the serial number or other identification mark shall be transferred to the finished interior of each section of pipe, fitting, or pipe special. The requirement to transfer serial numbers or other identification marks to the interior shall be at the purchaser’s option.

Sec. 6.2

Packaging and Shipping This standard has no applicable information for this section.

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Field Welding Of Steel Water Pipe 15

Sec. 6.3

Affidavit of Compliance The purchaser may require an affidavit from the constructor stipulating that all field welds on the pipe and attachments have been made in accordance with applicable provisions of this standard.

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1P–2M 43206-2017 (4/17) IW

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