AWS - Z49.1 - 焊接和切割割安全

?ANSIZ49.1:2012

AnAmericanNationalStandard

SafetyinWelding,Cutting,and

AlliedProcesses

ANSI Z49.1:2012

An American National Standard

Approved by the

American National Standards Institute

March 9,2012

Safety in

Welding,Cutting,and Allied Processes

Supersedes ANSI Z49.1:2005

Prepared by the

Accredited Standards Committee Z49,

Safety in Welding and Cutting

Secretariat

American Welding Society

Abstract

This standard covers all aspects of safety and health in the welding environment, emphasizing oxygen gas and arc welding processes with some coverage given to resistance welding. It contains information on protection of personneland the general area, ventilation, ?re prevention and protection, and con?ned spaces. A signi?cant section is devoted toprecautionary information, showing examples, and an extensive bibliography is included.

ANSI Z49.1:2012

American National Standard

Approval of an American National Standard requires review by ANSI that the requirements for due process, consensus,and other criteria for approval have been met by the standards developer.

Consensus is established when, in the judgment of the ANSI Board of Standards Review, substantial agreement has beenreached by directly and materially affected interests. Substantial agreement means much more than a simple majority, butnot necessarily unanimity. Consensus requires that all views and objections be considered, and that a concerted effort bemade toward their resolution.

The use of American National Standards is completely voluntary; their existence does not in any respect preclude any-one, whether he has approved the standards or not, from manufacturing, marketing, purchasing, or using products,processes, or procedures not conforming to the standards.

The American National Standards Institute does not develop standards and will in no circumstances give an interpreta-tion of any American National Standard. Moreover, no person shall have the right or authority to issue an interpretationof an American National Standard in the name of the American National Standards Institute. Requests for interpretationsshould be addressed to the secretariat or sponsor whose name appears on the title page of this standard.

CAUTION NOTICE:This American National Standard may be revised or withdrawn at any time. The procedures ofthe American National Standards Institute require that action be taken periodically to reaf?rm, revise, or withdraw thisstandard. Purchasers of American National Standards may receive current information on all standards by calling or writ-ing the American National Standards Institute.

International Standard Book Number: 978-0-87171-809-9

American Welding Society

550 N.W. LeJeune Road, Miami, FL 33126

?2012 by American Welding Society

All rights reserved

Printed in the United States of America

Photocopy Rights.No portion of this standard may be reproduced, stored in a retrieval system, or transmitted in anyform, including mechanical, photocopying, recording, or otherwise, without the prior written permission of the copyrightowner.

Authorization to photocopy items for internal, personal, or educational classroom use only or the internal, personal, oreducational classroom use only of speci?c clients is granted by the American Welding Society provided that the appro-priate fee is paid to the Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923, tel: (978) 750-8400;Internet: .

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ANSI Z49.1:2012

Personnel

(The following is the roster of the Committee at the time of ?nal committee action on the document.)

American National Standard Committee Z49

A. F. Manz, ChairmanS. P. Hedrick, Secretary

AMERICAN FOUNDRY SOCIETYF. H. Kohloff

AMERICAN COLLEGE OF OCCUPATIONAL AND ENVIRONMENTAL MEDICINEL. Lee

W. Milliken (Alternate)E. Favata (Alternate)

AMERICAN PUBLIC HEALTH ASSOCIATIONN. Tristani

AMERICAN SOCIETY OF SAFETY ENGINEERSE. R. Ziegler

T. J. Martin (Alternate)

AMERICAN WELDING SOCIETYD. Clark

S. P. Hedrick (Alternate)

CANADIAN STANDARDS ASSOCIATIONJ. J. Palach

CANADIAN WELDING BUREAUJ. MacRae

COMPRESSED GAS ASSOCIATIONA. F. Manz

R. A. Smith (Alternate)

INTERNATIONAL ASSOCIATION OF BRIDGE, STRUCTURAL, ORNAMENTAL AND REIFORCINGIRON WORKERSE. Abbott

INTERNATIONAL THERMAL SPRAY ASSOCIATIOND. Hayden

INTERNATIONAL SAFETY EQUIPMENT ASSOCIATION, INCORPORATEDJ. FranklinC. Fargo

MECHANICAL CONTRACTORS ASSOCIATION OF AMERICA, INCORPORATEDP. ChaneyW. Sperko

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ANSI Z49.1:2012

NATIONAL ELECTRICAL MANUFACTURERS ASSOCIATION, INCORPORATEDF. Stupczy

G. Winchester (Alternate)

NATIONAL FIRE PROTECTION ASSOCIATIOND. Duval

SHEET METAL WORKERS INTERNATIONALG. Batykefer

U.S. DEPARTMENT OF THE AIR FORCET. Pazell

R. G. Cox (Alternate)

U.S. DEPARTMENT OF THE ARMYS. C. GrahamR. Wright

U.S. DEPARTMENT OF LABORR. B. Bell (nonvoting)

U.S. DEPARTMENT OF THE NAVYE. Berg

U.S. PUBLIC HEALTH SERVICE (NIOSH)M. Gressel

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ANSI Z49.1:2012

Foreword

This foreword is not part of ANSI Z49.1:2012, Safety in Welding, Cutting and Allied Processes, but is included for informational purposes only.

The huge demands for production placed on the United States by World War II brought a tremendous expansion to theuse of welding. In mid 1943, it was recognized that some type of code or standard was needed relating to safe practicesfor performing welding. Under the auspices of the American Standards Association, the standard was drafted and pub-lished in 1944. It was entitled American War Standard Z49.1, Safety in Electric and Gas Welding, and CuttingOperations.

Following the war, the standard was ?rst revised in 1950. Subsequent revisions occurred in 1958, 1967, 1973, and 1983.Each updated the standard in accordance with changing technology and welding practices. The revisions up to andincluding 1973 were largely evolutionary and closely preserved the format of the original war standard.

In 1983, a major rewrite was undertaken to take proper account of the vast changes in welding which had occurred in the40 years of the standard’s existence and to clarify the somewhat patchwork presentation that had built up during the evo-lutionary revisions. The scope was rede?ned to address in greater detail the safety rules to be practiced by the welder andenforced by welding supervision and management. Provisions which had appeared in earlier editions, but which dealtmore with building construction and piping installation over which the welder had little control, were deleted. The 1988,1994, 1999, 2005, and 2012 revisions follow this same philosophy. Revisions are identi?ed by a vertical line in the mar-gin next to the text.

During the period of its publication, the American Standards Association has become the American National StandardsInstitute and War Standard ASA Z49.1-1944 has now become ANSI Z49.1:2012.

SUGGESTIONS

Comments and suggestions for the improvement of this standard are welcome. They should be sent to the Secretary,ANSI Z49 Committee, American Welding Society, 550 N.W. LeJeune Road, Miami, FL 33126.

REQUESTS FOR STANDARD INTERPRETATION

Of?cial interpretations of any of the technical requirements of this standard may be obtained by sending a request, in writing, to:

Managing Director, Technical ServicesAmerican Welding Society550 N.W. LeJeune RoadMiami, FL 33126

Requests not in writing cannot be considered for an of?cial interpretation (See Annex E).

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ANSI Z49.1:2012

This page is intentionally blank.

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ANSI Z49.1:2012

Table of Contents

Page No.

Personnel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iiiForeword. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vList of Tables. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xList of Figures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xPart I—General Aspects. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.Purpose and Scope. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.1Purpose. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.2Scope and Applicability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.3Exclusions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22.De?nitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22.1Approved. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22.2Con?ned Space. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32.3Cylinder Storage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32.4Immediately Dangerous to Life or Health (IDLH). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32.5Other De?nitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32.6Quali?ed Person. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32.7Shall. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32.8Should. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32.9Unit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32.10Welder. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33.General Provisions, Management, and Supervision. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33.1Setup and Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33.2Responsibilities. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44.Protection of Personnel and the General Area. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64.1Protection of the General Area. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64.2Eye and Face Protection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64.3Protective Clothing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94.4Noise Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104.5Respiratory Protective Equipment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104.6Training. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115.Ventilation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115.1General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115.2Breathing Zone Sampling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125.3Avoid the Fume. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125.4Types of Ventilation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125.5Special Ventilation Concerns. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136.Fire Prevention and Protection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146.1Areas Containing Combustibles. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146.2Fire Protection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

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6.36.4Hot-Work Authorization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16Welding or Cutting Containers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

7.Con?ned Spaces. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177.1Ventilation in Con?ned Spaces. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177.2Location of Service Equipment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187.3Adjacent Areas. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187.4Emergency Signal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187.5Attendants in Areas Immediately Dangerous to Life or Health (IDLH). . . . . . . . . . . . . . . . . . . . . . . . . . . 187.6Brazing Furnaces. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198.Public Exhibitions and Demonstrations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198.1Application. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198.2Supervision. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198.3Site. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198.4Fire Protection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208.5Protection of the Public. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208.6Cylinders. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208.7Process Hoses, Cables, and Conduits. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219.Precautionary Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219.1General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219.2Precautionary Information for Arc Welding and Related Processes and Equipment. . . . . . . . . . . . . . . . . 219.3Precautionary Information for Oxyfuel Gas Processes and Equipment. . . . . . . . . . . . . . . . . . . . . . . . . . . 219.4Hazardous Materials Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219.5Brazing Filler Metals Containing Cadmium. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229.6Brazing and Gas Welding Fluxes Containing Fluorides. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229.7Material Safety Data Sheets (MSDSs). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229.8Graphic Symbols. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239.9Hazard Communications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23Part II—Speci?c Processes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2410.Oxyfuel Gas Welding and Cutting Safety. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

10.1Scope. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2410.2Terminology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2410.3Oxygen and Combustibles. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2410.4Attachments for Gas Mixing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2410.5Torches. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2410.6Hose and Hose Connections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2510.7Pressure-Reducing Regulators. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2610.8Compressed and Oxyfuel Gas Cylinders (Containers). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2710.9Cylinder Manifolding. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3211.Arc Welding and Cutting Equipment Safety. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

11.1General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3211.2Safety Aspects in Selection of Arc Welding Equipment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3311.3Installation of Arc Welding Equipment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3411.4Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3511.5Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3812.Resistance Welding Safety. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

12.1General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3912.2Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4012.3Guarding. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4012.4Electrical. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4112.5Static Safety Devices. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

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12.6Ventilation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4412.7Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4413.Electron Beam Welding and Cutting Processes (EBW and EBC). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

13.1General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4413.2Potential Hazards. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4414.Laser Beam Cutting and Welding. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

14.1General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4515.Brazing and Soldering Safety. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

15.1General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4515.2Potential Hazards. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45Annex A (Informative)—American Welding Society Safety and Health Standards List. . . . . . . . . . . . . . . . . . . . . . 49Annex B (Informative)—List of Other Sources. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51Annex C (Informative)—List of Publishers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53Annex D (Informative)—Master Chart of Welding and Joining Processes and Master Chart of

Allied Processes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

Annex E (Informative)—Guidelines for the Preparation of Technical Inquiries for the Z49 Committee. . . . . . . . . . 57

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List of Tables

Table1

Page No.

Guide for Shade Numbers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

List of Figures

Figure1234

Page No.

Precautionary Information for Arc Welding Processes and Equipment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22Precautionary Information for Oxyfuel Gas Processes and Equipment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22Precautionary Information for Brazing Filler Metals Containing Cadmium. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23Precautionary Information for Brazing and Gas Welding Fluxes Containing Fluorides. . . . . . . . . . . . . . . . . . . . 23

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ANSI Z49.1:2012

Safety in Welding,Cutting,and Allied Processes

(American National Standard Z49.1:2012 uses a two-column format to provide both speci?c requirements and sup-porting information. The left column is designated as “Standard Requirements” and the right column is designated as“Explanatory Information.” The paragraph number of the Explanatory Information is preceded by the letter “E.”)

Standard RequirementsExplanatory Information

Part I

General Aspects

1.Purpose and Scope

1.1Purpose.This standard is for the protection ofpersons from injury and illness and the protection ofproperty (including equipment) from damage by ?re andexplosions arising from welding, cutting, and alliedprocesses.

E1.1Beginning with the revision of 1983, the scope ofANSI Standard Z49.1 has been refocused towards thosesafe practices for performing welding, cutting, and alliedprocesses, which are generally within the implementationcontrol of the welder or the weld shop management. It iswritten in a manner suitable for issuance to the welderand shop management to give practical information tohelp them perform these functions safely. It also containsinformation useful to educators, industrial hygienists,engineers, and similar parties also responsible for safetyand health in welding. With this refocused scope, someprovisions which appeared in prior editions have beendeleted. Those were provisions which dealt more inmatter of building design and construction, facilitypipelines, and electrical installations. Those provisions,of course, are still important and necessary and must befollowed. They are not provisions usually under theimmediate control of welding and cutting operations.E1.2Speci?c provisions are included for oxyfuel gas andarc welding and cutting, resistance welding, electronbeam welding, laser beam cutting and welding, andbrazing and soldering.

However, the requirements of this standard are generallyapplicable to the other welding processes such as sub-merged arc welding and allied processes shown in theAmerican Welding Society Master Chart of Welding andAllied Processes, included in Annex D.

1.2Scope and Applicability.This standard shall be forthe guidance of educators, operators, managers, andsupervisors in the safe setup and use of welding andcutting equipment, and the safe performance of weldingand cutting operations.

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ANSI Z49.1:2012

1.3Exclusions.This standard shall not pertain to thefollowing:

(1)Guidelines for the design or manufacture ofequipment

(2)Building piping systems

(3)Pipeline protection systems and station outletequipment

(4)Bulk gas supply systems

(5)Building electrical installations.

E1.3Some of these were included in former issues of thestandard. These items were eliminated from ANSI Z49.1to avoid their being included in two separate standardsunder separate auspices which can lead to con?ict orconfusion between standards.

These are contained in standards and codes of theNational Fire Protection Association (NFPA) as follows:(1)Oxyfuel gas piping systems, pipeline protectivedevices, and station outlet equipment—NFPA 51,Standard for the Design and Installation of Oxygen-FuelGas Systems for Welding, Cutting, and Allied Processes(2)Storage and manifolding of multiple gas cylin-ders—NFPA 51

(3)Acetylene generators and calcium carbide storage—NFPA 51

(4)Bulk oxygen systems—NFPA 50, Standard forBulk Oxygen Systems at Consumer Sites

(5)Bulk LP-Gas and MPS systems—NFPA 58,Storage and Handling of Lique?ed Petroleum Gases(6)Building electrical installations—NFPA 70,National Electrical Code?

(7)Industrial machinery—NFPA 79, ElectricalStandard for Industrial Machinery

1.4Equivalency.Nothing in this standard is intended toprevent the use of systems, methods, or devices ofequivalent or superior quality, strength, ?re resistance,effectiveness, durability, and safety over those prescribedby this standard.

1.4.1Technical documentation shall be submitted tothe authority having jurisdiction to demonstrateequivalency.

1.4.2The system, method, or device shall be approvedfor the intended purpose by the authority havingjurisdiction.

2.De?nitions

The following de?nitions shall apply to this standard.2.1Approved.Approvedand approvalas used in thisstandard mean acceptable to the authority havingjurisdiction.

2.1.1Authority Having Jurisdiction.This termrefers to the organization, of?ce, or individualresponsible for “approving” equipment, an installation,or a procedure.

2.1.2Listed.This term means the equipment ormaterial included in a list published by a nationallyrecognized testing laboratory that maintains periodicinspection of production of listed equipment or materials.

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ANSI Z49.1:2012

2.2Con?ned Space.Refers to a relatively small orrestricted space such as a tank, boiler, pressure vessel, orsmall compartment. Con?nement implies poorventilation as a result of construction, size, or shaperather than restriction of egress of personnel.

2.3Cylinder Storage.Refers to cylinders ofcompressed gas standing by on the site (not those in useor attached ready for use).

2.3.1Cylinders in Use.This term refers to thefollowing:

(1)Cylinders connected for use;

(2)A single cylinder for each gas to be used, in theuse location, ready to be connected; or

(3)A one day supply of cylinders, in the use location,ready to be connected.

2.4Immediately Dangerous to Life or Health(IDLH).IDLH is a condition which poses an immediatethreat of loss of life; may result in irreversible orimmediate severe health effects, or other conditionswhich could impair escape.

2.5Other De?nitions.All other welding terms usedherein are in accordance with the current edition of AWSA3.0M/A3.0, Standard Welding Terms and De?nitions.2.6Quali?ed Person.A person who by reason oftraining, education, and experience is knowledgeable inthe operation to be performed and is competent to judgethe hazards involved.

2.7Shall.Shallis used to indicate provisions which aremandatory.

2.8Should.Shouldor it is recommended thatis used toindicate provisions which are not mandatory.

2.9Unit.Numerical values are given in U.S. customaryand metric (SI) units.

2.10Welder.“Welder” and “welding operator” as usedherein are intended to designate any operator of electricor oxyfuel gas welding or cutting equipment, or alliedprocesses.

E2.2For additional information, see ANSI Z117.1,Safety Requirements for Con?ned Spaces, and applicableOSHA standards 29 CFR 1910.145 for General Industry,29 CFR 1926.353(b) for Construction, and 29 CFR 1915subpart B for Maritime.

E2.10This term also includes educators and students thatare engaged in similar activities.

3.General Provisions, Management,and Supervision

3.1Setup and Installation

3.1.1Equipment and Condition Maintenance.Allwelding and cutting equipment shall be inspected asrequired to assure it is in safe operating condition. Whenfound to be incapable of reliable safe operation, theequipment shall be repaired by quali?ed personnel priorto its next use or withdrawn from service.

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ANSI Z49.1:2012

3.1.2Operation.All equipment shall be operated inaccordance with manufacturers’ recommendations andinstructions, provided these are consistent with thisstandard.

3.1.3Heavy Portable Equipment on Wheels.Heavy portable equipment mounted on wheels shall besecured in position to prevent accidental movementbefore operations are started.

3.2Responsibilities.Operators and management shallrecognize their mutual responsibilities for safety inwelding and cutting.3.2.1Management

E3.1.2Most manufacturers provide safetyinformation along with operational and maintenanceinformation. Operators should become familiar with, andfollow, that safety information.

E3.1.3See 7.2.2 for additional information.

E3.2.1Management, as used in this standard, includesall persons who are responsible for welding operationssuch as owners, contractors, educators, and others.

3.2.1.1Training.Management shall assure thatwelders and their supervisors are trained in the safeoperation of their equipment, the safe use of the process,and emergency procedures.

3.2.1.2Hazard Communication.Managementshall assure that hazards and safety precautions arecommunicated to and understood by workers prior to thestart of work.

E3.2.1.2The hazards which may be involved inwelding are communicated to users through manufacturers’instructions, material safety data sheets, and productlabeling. See Clause 9, Precautionary Information, of thisstandard. See especially OSHA 29 CFR, Section1910.1200, Hazard Communication Standard.

E3.2.1.3See 6.3 for additional information.

3.2.1.3Designated Areas and Responsibilities.Management shall designate approved areas, andestablish procedures for safe welding and cutting.A designated management representative shall be respon-sible for authorizing welding and cutting operations inareas not speci?cally designed or approved for suchprocesses. Management shall assure that the individual isaware of the hazards involved and familiar with the pro-visions of this standard.

3.2.1.4Approved Equipment.Management shallassure that only approved apparatus, such as torches,manifolds, regulators, pressure reducing valves, acetylenegenerators, welding machines, electrode holders, andpersonal protective devices are used.

3.2.1.5Contractors.Management shall selectcontractors to perform welding who provide trained andquali?ed personnel, and who have an awareness of therisks involved.

Management shall advise contractors about ?ammablematerials or hazardous conditions that are speci?c to thejob site.

Management shall advise contractors about ?ammablematerials or hazardous conditions of which they may notbe aware.

E3.2.1.5For the purposes of this standard, incontract operations, the responsibility for the welder restswith the contractor supervisor and the contractormanagement.

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ANSI Z49.1:2012

3.2.2Supervisors

E3.2.2Supervisors, as used in this standard, includeall persons who are responsible for supervising weldingoperations such as owners, contractors, educators, andothers.

3.2.2.1Safe Use of Equipment.Supervisors shallbe responsible for the safe handling of the weldingequipment and for the safe use of the welding process.3.2.2.2Fire Hazards.Supervisors shall determinewhat ?ammable and combustible materials are present orlikely to be present in the work location. They shallensure that such materials are not exposed to ignition bytaking one or more of the following actions:

(1)Have the work moved to a location free fromcombustibles and away from hazardous areas.

(2)Have the combustibles moved a safe distancefrom the work or properly shielded against ignition if thework cannot readily be moved.

(3)Schedule welding and cutting so that such materi-als are not exposed during welding and cutting opera-tions.

3.2.2.3Authorization.Authorization for thewelding or cutting operations shall be obtained from the designated management representative prior to thecommencement of hot work or entering a con?ned space.Supervisors shall oversee that the welder has approvalthat conditions are safe before going ahead.

3.2.2.4Protective Equipment and FireProtection.Supervisors shall assure that proper personalprotective and ?re protection equipment is used. Theyshall assure that ?re protection and ?re extinguishingequipment are properly located at the site, and that ?rewatchers are assigned and hot-work authorizationprocedures are followed where required.

Where ?re watchers are not required, a ?nal inspectionshall be made by supervision.3.2.3Welders

3.2.3.1Safe Handling of Equipment.Weldersshall understand the hazards of the operation to beperformed and the procedures being used to controlhazardous conditions. Welders shall handle theequipment safely and use it so as not to endanger livesand property.

3.2.3.2Permission.Welders shall have permissionof management before starting to weld or cut. Weldersshall continue to weld or cut only so long as conditions are unchanged from those under which permission wasgranted.

3.2.3.3Safe Conditions.Welders shall cut orweld only where all safety precautions have been met.

E3.2.3.1Welders make the ?nal choice to weld ornot to weld. They need to understand the hazards beforeproceeding.

E3.2.2.2See also Clause 6, Fire Prevention andProtection.

E3.2.2.3See 6.3 and 7.1. There are somecircumstances where the authorization must be written;for example, permit-required con?ned space entry. Seeespecially OSHA 29 CFR, Section 1910.146, Permit-Required Con?ned Space Standard.

E3.2.2.4See 6.2, 6.3, and 6.4.

The inspection is usually made one-half hour after thecompletion of welding operations to detect and extin-guish possible smoldering ?res. Be alert for circum-stances which may require an extension of the ?nalinspection interval.

E3.2.3.2See 6.3. In many facilities, managementgrants blanket permission for cutting and welding where?re hazards are not present.

E3.2.3.3Do not work alone where conditions areespecially hazardous, such as where electric shock is ahazard, or where ventilation is poor, etc.

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ANSI Z49.1:2012

3.2.3.4Marking Hot Materials.Where othersmay unknowingly come in contact with hot materialremaining from welding, a notice shall be posted.

4.Protection of Personnel and theGeneral Area

4.1Protection of the General Area

4.1.1Equipment.Welding equipment, machines,cable, and other apparatus shall be located so that it doesnot present a hazard to personnel. Good housekeepingshall be maintained.

4.1.2Signs.Signs shall be posted designatingwelding areas, and indicating that eye protection andother applicable protective devices shall be worn.4.1.3Protective Screens.Workers or other personsadjacent to the welding areas shall be protected from theradiant energy and spatter of welding and cutting bynoncombustible or ?ame-resistant screens or shields, orshall be required to wear eye and face protection, andprotective clothing.

E4.1.1For example, locations such as passageways,ladders, or stairways should be kept clear.

E4.1.2Additional precautionary information shouldbe posted when circumstances present additional hazards.E4.1.3Radiation-protective, semitransparent materialsare permissible. Screens should permit circulation of air at?oor level as well as above the screen. Refer to NFPA701, Standard Methods of Fire Tests for FlamePropagation Textiles and Films, for information onignition resistance criteria. For additional information onradiation protection, see 4.2.2. The intensity of arc radiantenergy depends on many factors, including current,voltage, and the materials employed. Refer to 4.2.2.E4.1.4Finishes formulated with pigments such astitanium dioxide or zinc oxide have low re?ectivity toultraviolet radiation. Color pigments may be added ifthey do not increase re?ectivity. Lamp black has beenrecommended as a paint additive in the past, but itreduces visible light and is accordingly less desirable inview of the need for good lighting as well as ultravioletradiation absorption.

Pigments based on powdered or ?aked metals are not rec-ommended because of their high re?ectivity of ultravioletradiation.

Welding curtains are another means of reducing re?ectiv-ity. For further guidance, see Ultraviolet Re?ectance ofPaint, published by and available from the AmericanWelding Society.

4.1.4Re?ectivity.Where arc welding is regularlycarried out, adjacent walls and other surfaces shall havelow re?ectivity to ultraviolet radiation.

4.1.5Welding Booths.Where operations permit,welding stations shall be separated by noncombustiblescreens or shields with characteristics as described in4.1.3.

4.2Eye and Face Protection.Eye and face protectionshall comply with ANSI/ISEA Z87.1, Occupational and Educational Personal Eye and Face ProtectionDevices.

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ANSI Z49.1:2012

4.2.1Type Selection

4.2.1.1Arc Welding and Arc Cutting with OpenArcs.Helmets or hand shields with ?lter lenses and coverlenses shall be used by operators and nearby personnelwhen viewing the arc.

Protective spectacles with side shields, arc goggles, orother approved eye protection shall also be worn.

E4.2.1.1Welding helmets with ?lter lenses areintended to protect users from arc rays and from weldsparks and spatter which impinge directly against thehelmet. To protect the user from impact hazards when thewelding helmet may be raised during use, spectacles withlateral protection or goggles should also be worn.The spectacles or goggles may have either clear or ?l-tered lenses, depending upon the amount of exposure toadjacent welding or cutting radiation (see Table 1).Others in the immediate welding area should wear similareye protection. Welding helmets will not protect againstthe severe impact of fragmenting grinding wheels, abra-sive discs, or explosive devices.

4.2.1.2Oxyfuel Gas Welding and Cutting andSubmerged Arc Welding.Welding goggles, or weldinghelmet or welding faceshield over spectacles or gogglesshall be worn during all oxyfuel gas welding and cutting,and submerged arc welding operations.

4.2.1.3Resistance Welding and Brazing.Operators of resistance welding or brazing equipmentand their helpers shall wear welding goggles, or weldinghelmet or welding faceshield over spectacles or gogglesfor eye and face protection.

4.2.1.4Large Area Viewing.For large areaviewing, such as training, demonstrations, shows, andcertain automatic welding operations, a large ?lterwindow or curtain shall be permitted to be used in lieu ofeye and face protection. The radiation transmission ofwindow or curtain material shall be equivalent to that inANSI/ISEA Z87.1 for shade number appropriate to thewelding or cutting operation.

Additionally, suitable arrangements shall be provided toprevent direct viewing of the arc without ?lter protectionand to protect viewers from sparks and chipped slag.4.2.2Requirements for Eye and Face Protection4.2.2.1Filter Lenses.Filter lenses shall be inaccordance with ANSI/ISEA Z87.1, and the shade shallbe selected in accordance with AWS F2.2, Lens ShadeSelector,or Table 1.

E4.2.2.1See latest edition of AWS F2.2. Filterlenses should be free from any ?aws which may distract,block, or otherwise impair vision.

Persons with special eye conditions should consult theirphysician for speci?c information on protective equipment.E4.2.2.2Welding helmets, hand shields, andgoggles complying with ANSI/ISEA Z87.1 are limited incombustibility.

E4.2.1.2It is recommended that such eyeprotection offer lateral (side) coverage. (See Table 1.)

4.2.2.2Material Properties.Helmet and handshield bodies shall be made of material that is thermallyand electrically insulating, noncombustible or self-extinguishing, and opaque to visible, ultraviolet, andinfrared radiation, and shall comply with the requirementsof ANSI/ISEA Z87.1, Occupational and EducationalPersonal Eye and Face Protection Devices.

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ANSI Z49.1:2012

Table 1Guide for Shade Numbers (from AWS F2.2:2001(R2010), Lens Shade Selector)Shade numbers are given as a guide only and may be varied to suit individual needs.Electrode Size in (mm)Less than 3/32 (2.4)3/32–5/32 (2.4–4.0)5/32–1/4 (4.0–6.4)More than 1/4 (6.4)Arc Current (Amperes)Less than 6060–160160–250250–550Less than 6060–160160–250250–500Less than 5050–150150–500Less than 500500–1000Less than 2020–100100–400400–800Less than 2020–4040–6060–8080–300300–400400–800———Plate ThicknessinOxyfuel Gas Welding (OFW)LightMediumHeavyOxygen Cutting (OC)LightMediumHeavyaProcessShielded MetalArc Welding (SMAW)Minimum SuggestedaProtective Shade No. Shade(Comfort)78101171010108810101168101145688910————101214—11121410121412146 to 81012144568912143 or 4214SuggestedaShade No. (Comfort)4 or 55 or 66 or 83 or 44 or 55 or 6Gas Metal Arc Welding(GMAW) and Flux Cored ArcWelding (FCAW)Gas Tungsten Arc Welding(GTAW)Air Carbon Arc (Light)Cutting (CAC-A) (Heavy)Plasma Arc Welding (PAW)Plasma Arc Cutting (PAC)Torch Brazing (TB)Torch Soldering (TS)Carbon Arc Welding (CAW)mmUnder 33 to 13Over 13Under 2525 to 150Over 150Under 1/81/8 to 1/2Over 1/2Under 11 to 6Over 6As a rule of thumb, start with a shade that is too dark to see the weld zone. Then go to a lighter shade which gives suf?cient view of the weld zonewithout going below the minimum. In oxyfuel gas welding, cutting, or brazing where the torch and/or the ?ux produces a high yellow light, it is desir-able to use a ?lter lens that absorbs the yellow or sodium line of the visible light spectrum.8

ANSI Z49.1:2012

4.2.2.3Area of Protection.When there is apossibility of hazardous exposure, helmets and handshields shall protect the face, forehead, neck, and ears toa vertical line in back of the ears, from direct radiantenergy from the arc, and from direct weld spatter.4.2.2.4Effect of Materials on Skin.Materials incontact with the body shall not readily irritate or discolorthe skin.

4.2.2.5Goggle Ventilation.Goggles shall bevented to deter fogging of the lenses in accordance withANSI Z87.1.

4.2.2.6Outer Cover Lenses.Outer lenses shall beprovided to protect the ?lter lens or ?lter lens in goggles,helmets, or hand shields from welding spatter, pitting, orscratching. Outer cover lenses shall be of clear glass orself-extinguishing plastic, but need not be impact resistant.4.2.2.7Inner Lenses or Plates.When the “liftfront” type of welders’ helmet is used, there shall be a?xed impact resistant safety lens or plate on the inside ofthe frame nearest to the eyes to protect the welder against?ying particles when the front is lifted.

4.2.2.8Marking.Filter lenses shall bear somepermanent distinctive marking by which the manufacturermay be readily identi?ed. In addition, all ?lter lenses shallbe marked with their shade number and in accordancewith the requirements of ANSI Z87.1.

4.2.2.9Radiation Transmittance Properties.All?lter lenses shall meet the “Ultraviolet, Luminous andInfrared Transmittance” requirements of ANSI Z87.1.4.2.2.10Maintenance.Helmets, handshields, andgoggles shall be well maintained, and should not betransferred from one employee to another without beingcleaned.

4.3Protective Clothing.Clothing shall be selected tominimize the potential for ignition, burning, trapping hotsparks, or electric shock.

E4.2.2.3Some low current processes, such as withmicro Plasma Arcs, may not present a hazardousradiation exposure, but may have a spatter exposure.Therefore, operators should be provided with safetyglasses even if there is no radiation hazard.

E4.2.2.10For methods of cleaning, refer to themanufacturer’s instructions.

E4.3Heavier materials such as woolen clothing or heavycotton are preferable to lighter materials because they aremore dif?cult to ignite. Cotton clothing, if used forprotection, should be chemically treated to reduce itscombustibility. Clothing treated with ?ame resistantmaterials may lose some of its protective characteristicsafter repeated washing or cleaning. Materials which canmelt and cause severe burns should not be used asclothing when welding or cutting.

Sparks may lodge in rolled-up sleeves, pockets of clothing,or cuffs of overalls or trousers. It is therefore recommendedthat sleeves and collars be kept buttoned and pockets beeliminated from the front of clothing. When pockets are pre-sent, they should be emptied of ?ammable or readily com-bustible materials. Trousers or overalls should not have cuffsand should not be turned up on the outside. Trousers shouldoverlap shoe tops to prevent spatter from getting into shoes.

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Frayed clothing is particularly susceptible to ignition andburning and should not be worn when welding or cutting.Refer to 11.3 and 11.4.

4.3.1Selection.Clothing shall provide suf?cientcoverage, and be made of suitable materials, to minimizeskin burns caused by sparks, spatter, or radiation.

E4.3.1Appropriate protective clothing for anywelding and cutting operation will vary with the size,nature, and location of the work to be performed.Clothing should be kept clean, as oil and grease canreduce its protective qualities.

E4.3.2Gloves made of leather, rubber, or othersuitable materials are recommended. Insulating liningsshould be used to protect areas exposed to high radiantenergy. See E11.2.2.

E4.3.4In production work, a sheet metal screen infront of the worker’s legs can provide further protectionagainst sparks and molten metal in cutting operations.

4.3.2Gloves.All welders and cutters shall wearprotective ?ame-resistant gloves. All gloves shall be ingood repair, dry, and capable of providing protectionfrom electric shock by the welding equipment.

4.3.4Leggings.For heavy work, ?ame-resistantleggings or other equivalent means shall be used to giveadded protection to the legs, when necessary.

4.3.5Capes and Sleeves.Cape sleeves or shouldercovers with bibs made of leather or other ?ame-resistantmaterial shall be worn during overhead welding, cutting,or other operations, when necessary.

4.3.6Other Protective Clothing.Properly ?tted?ame-resistant plugs in the ear canals, or equivalentprotection, shall be used where hazards to the ear canalsexist.

Caps made from ?ame resistant material shall be wornunder helmets, when necessary, to prevent head burns.4.4Noise Control.Noise shall be controlled at the sourcewhen feasible. When control methods fail to bring noiseexposure within allowable limits, personal protectivedevices such as ear muffs or ear plugs shall be used.

E4.4In welding, cutting, and allied operations, noiseresults from the process and from the equipment. Processesthat may produce high noise levels are air carbon arccutting and gouging, and plasma arc cutting and gouging,plus some oxyfuel processes and equipment, and supportequipment.

Equipment which sometimes have a high noise level areengine driven generators. Other equipment and processes,such as chipping and grinding, may produce hazardousnoise exposure, depending on speci?c circumstances.

4.5Respiratory Protective Equipment.When controlssuch as ventilation fail to reduce air contaminants toallowable levels or when the implementation of suchcontrols are not feasible, respiratory protective equipmentshall be used to protect personnel from hazardousconcentrations of airborne contaminants.

4.5.1Only approved respiratory protective equipmentshall be used.

E4.5See 5.1 for a discussion of allowable levels. Forguidance on use of respirators in con?ned spaces, refer toClause 7, Con?ned Spaces, of this standard.

E4.5.1Approvals of respiratory equipment are issuedby the National Institute for Occupational Safety andHealth (NIOSH) or the Mine Safety and HealthAdministration (MSHA).

E4.5.2Federal regulations for respirator use dictatethat respirators not be passed from one employee toanother without being sanitized per OSHA 29 CFR,Section 1910.134, Respiratory Protection Standard.

4.5.2Whenever the use of respirators is required, aprogram to establish the proper selection and use ofrespirators shall be implemented.

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4.5.3Compressed air for air supplied respirators orother breathing equipment shall at least meet the Grade Drequirements of the Compressed Gas AssociationANSI/CGA G-7.1, Commodity Speci?cation for Air.4.6Training.Persons exposed to welding hazards shallE4.6Persons include workers and their immediatebe trained in the use of, and understand the reasons for,supervisors. See appropriate ANSI standards onprotective clothing and equipment.

protective clothing and equipment.

5.Ventilation

5.1General. Adequate ventilation shall be provided forE5.1The factors for determining adequate ventilationall welding, cutting, brazing, and related operations.include the following:

Adequate ventilation shall be enough ventilation such that(1)Volume and con?guration of the space in whichpersonnel exposures to hazardous concentrations ofoperations occur (see Clause 7, Con?ned Spaces)

airborne contaminants are maintained below the allowable(2)Number and type of operations generating conta-limits speci?ed by the authority having jurisdiction.minants

Respiratory protective equipment as speci?ed in 4.5 shall(3)Concentrations of speci?c toxic or ?ammablebe used when adequate ventilation is not practical.

contaminants being generated (see 5.2)

(4)Natural air ?ow (rate and general atmosphericconditions where work is being done)

(5)Location of the welder’s and other person’sbreathing zones in relation to the contaminants or sourcesIn cases where the values for allowable exposure limits varyamong recognized authorities, the lower values should beused to effect the maximum personnel protection.Fumes and gases from welding and cutting cannot beclassi?ed simply. The composition and quantity of fumesand gases are dependent upon the metal being worked,the process and consumables being used, coatings on thework such as paint, galvanizing, or plating, contaminantsin the atmosphere such as halogenated hydrocarbonvapors from cleaning and degreasing activities, as well asthe factors itemized in this section for adequate ventila-tion. A good practice to reduce the generation of fumesand gases from paints and primers is to grind or sand thesurface to bare metal prior to welding. Note however thatthe method of removal may generate particulates thatrequire worker protection.

In welding and cutting, the composition of the fumes isusually different from the composition of the electrode orconsumables.

Reasonably expected fume products of normal operationinclude those originating from consumables, base metalsand coating, and the atmospheric contaminants noted.Reasonably expected gaseous products include carbonmonoxide, carbon dioxide, ?uorides, nitrogen oxides,and ozone.

The recommended way to determine adequate ventilationis to sample for the composition and quantity of fumesand gases to which personnel are exposed (see 5.2).

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The Occupational Safety and Health Administration(OSHA) or others may be the authority having jurisdiction.Although not an authority having jurisdiction, many ofthese exposure limits are adopted from the publicationsof the American Conference of Governmental IndustrialHygienists (ACGIH). Refer to E4.1.3, ProtectiveScreens, and Clause 7, Con?ned Spaces.

5.2Breathing Zone Sampling.Where concentrations ofairborne fume contaminants are to be determined bysampling of the atmosphere, sampling shall be inaccordance with AWS F1.1, Method for SamplingAirborne Particulates Generated by Welding and AlliedProcesses. When a helmet is worn, the samples shall becollected inside the helmet in the welder’s breathing zone.5.3Avoid the Fume.Welders and cutters shall takeprecautions to avoid breathing the fume directly.

E5.3Avoiding the fume can be done by positioning of thework, the head, or by ventilation which captures or directsthe fume away from the face. Tests have shown that fumecontrol is more effective when the air ?ow is directedacross the face of the welder, rather than from behind.Most of the fume appears as a clearly visible plume whichrises directly from the spot of welding or cutting.E5.4Natural ventilation is acceptable for welding,cutting, and related processes where the necessaryprecautions are taken to keep the welder’s breathing zoneaway from the fumes and where sampling of theatmosphere shows that concentration of contaminants arebelow the allowable limits referenced in 5.1.

Mechanical ventilation includes local exhaust, localforced air, and general area mechanical air movement.Local exhaust ventilation is preferred.

Local exhaust ventilation means ?xed or moveableexhaust hoods placed as near as practicable to the workand able to maintain a capture velocity suf?cient to keepairborne contaminants below the allowable limits refer-enced in 5.1. Local forced ventilation means a local airmoving system (such as a fan) placed so that it moves theair horizontally across the welder’s face. Generalmechanical ventilation may be necessary in addition tolocal forced ventilation.

Examples of general mechanical ventilation are roofexhaust fans, wall exhaust fans, and similar large area airmovers.

General mechanical ventilation is not usually as satisfac-tory for health hazard control as local mechanical ventila-tion. It is often helpful, however, when used in addition tolocal ventilation.

Ventilation should not produce more than approximately100 feet per minute (0.5 meters per second) air velocity atthe work (welding or cutting) zone. This is to prevent dis-turbance of the arc or ?ame. It should be recognized that

5.4Types of Ventilation.If natural ventilation is notsuf?cient to maintain contaminants below the allowablelimits referenced in 5.1, mechanical ventilation orrespirators shall be provided.

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approximately 100 feet per minute (0.5 meters per sec-ond) air velocity is a recommended maximum value forquality control purposes in welding and cutting. It is notintended to imply adequacy in contaminant control forworker health protection.

5.4.1Recirculation.Precautions shall be taken toensure that excessive levels of contaminants are notdispersed to other work areas. When air is recirculated,the buildup of the contaminants beyond allowable limitsreferred to in 5.1 shall be prevented. Manufacturer’sprecautions pertaining to consumables and processesshall be observed.

5.4.2Air Cleaners.Air cleaners shall be used only ifit has been determined by atmospheric sampling that theymaintain the level of hazardous contaminants below theallowable limits referred to in 5.1.

E5.4.2Air cleaners are devices which circulatecontaminated air through ?lters and return the ?ltered airto the ambient environment.

The devices reduce the amount of air exhausted to theoutdoors and reduce make-up air requirements. Most ?l-ters do not remove gases. Therefore, adequate monitoringmust be done to assure concentrations of harmful gasesremain below allowable limits.

5.5Special Ventilation Concerns

5.5.1Low Allowable-Limit Materials.Whenever thefollowing materials are identi?ed as other than traceconstituents in welding, brazing, or cutting operations, andunless breathing zone sampling under the most adverseconditions has established that the level of hazardousconstituents is below the allowable limits of 5.1, the specialventilation precautions given in 5.5.1.1 and 5.5.1.2 shall betaken: Antimony, Arsenic, Barium, Beryllium Cadmium,Chromium, Cobalt, Copper, Lead, Manganese, Mercury,Nickel, Ozone, Selenium, Silver, Vanadium.

5.5.1.1Con?ned Spaces.Whenever materialsexceed the allowable limits referred to in 5.5.1 incon?ned space operations, local exhaust mechanicalventilation and, when required, respiratory protectionshall be used (see also Clause 7).

5.5.1.2Adjacent Persons.All persons in theimmediate vicinity of welding or cutting operationsinvolving the materials listed in 5.5.1 shall be similarlyprotected.

5.5.2Fluorine Compounds.In con?ned spaces,when welding or cutting operations involve ?uxes,coatings, or other materials that contain ?uorinecompounds, local exhaust mechanical ventilation orrespiratory protection shall be provided.

E5.5.2Fumes and gases from ?uorine compounds canbe dangerous to health and can burn eyes and skin oncontact. See 9.6 for labeling of brazing and gas welding?uxes containing ?uorides.

In open spaces, when welding or cutting involves materi-als containing ?uorine compounds, the need for localexhaust ventilation or respiratory protection will dependupon the individual circumstances. However, experiencehas shown that such protection is desirable for ?xed loca-tion production welding and for all production weldingE5.5.1Certain materials, sometimes contained in theconsumables, base metals, coatings, or atmospheres ofwelding or cutting operations, have very low allowablelimits.

Refer to material safety data sheets provided by the man-ufacturer to identify any of the materials listed here.

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on stainless steels. Such protection is not necessary whenair samples taken in breathing zones indicate that the ?u-orides liberated are below allowable limits.

5.5.3Zinc or Copper.Welding or cutting operationsinvolving consumables, base metals, or coatingscontaining zinc or copper shall be done as described in5.5.2 for ?uorine compounds.

5.5.4Cleaning Compounds.When using cleaningcompounds prior to welding, manufacturers’ instructionsshall be followed.

5.5.4.1Chlorinated Hydrocarbons.Degreasing orcleaning operations involving chlorinated hydrocarbonsshall be so located that vapors from these operations willnot reach or be drawn into the atmosphere surroundingmolten weld metal or the arc.

In addition, these materials shall be kept out of atmos-pheres penetrated by the ultraviolet radiation of arc welding operations.

5.5.5Arc and Gas Cutting.Oxygen cutting usingeither a chemical ?ux or iron powder, gas-shielded arccutting, or plasma cutting shall be done using localmechanical ventilation or other means adequate toremove the fumes generated.

E5.5.4.1A reaction product having a characteristicobjectionable, irritating odor, and including highly toxicphosgene gas is produced when such vapors enter theatmosphere of arc welding operations. Low levels ofexposure can produce feeling of nausea, dizziness, andmalaise. Heavy exposures may produce serious healthimpairments.

E5.5.3Fumes containing zinc or copper compoundsmay produce symptoms of nausea, dizziness, or fever,sometimes called “metal fume fever.”

E5.5.5Use of water tables, water curtains, underwatercutting, ventilation or combination of these will dependupon the individual circumstances. Experience hasshown that such protection is desirable for ?xed locationproduction welding and for all production welding onstainless steels. Such protection is not necessary when airsamples taken in breathing zones indicate that thematerials liberated are below allowable limits.

E5.5.6Where complete combustion takes place in orat the furnace during the heating cycle, the ventilationrequirement may diminish.

E5.5.7Protection of the employees in the area mayrequire training, respiratory protection, wetting down theasbestos, and use of special protective clothing in additionto special ventilation. See also OSHA asbestos standards.

5.5.6Brazing Furnaces.In all cases, adequatemechanical ventilation shall be provided to remove allexplosive or toxic gases which may emanate fromfurnace purging and brazing operations.

5.5.7Asbestos.Where welding or cutting is to bedone on surfaces that are covered by asbestos insulation,the regulations of the authority having jurisdiction shallbe consulted before beginning the work.

6.Fire Prevention and ProtectionE6.Fire Prevention

For more information on the following precautions, as wellas on the ?re protection and prevention responsibilities ofwelders, supervisors (including outside contractors), andmanagement, see NFPA 51B, Standard for FirePrevention During Welding, Cutting, and Other Hot Work.

6.1Areas Containing Combustibles

E6.1Welding and cutting should preferably be done inspecially designated areas which have been designed andconstructed to minimize ?re risk. Good housekeepingshould be maintained.

6.1.1Conditions for Cutting or Welding.Nowelding or cutting shall be done unless the atmosphere isnon?ammable and unless combustibles are moved awayor protected from ?re hazards.

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6.1.2Work Movable.Where practical, the workshall be moved to a designated safe location.

6.1.3Fire Hazards Movable.Where it is notpractical to move the work, all movable nearby ?rehazards shall be relocated to a safe location.

6.1.4Work and Fire Hazards Immovable.Wherethe work and ?re hazards are not movable, safeguardsshall be used to protect the immovable ?re hazards andnearby personnel from the heat, sparks, and slag.6.1.4.1Combustible Floors.Combustible ?oorsshall be clean and protected by wetting with water orcovering with damp sand, sheet metal, or the equivalent.Provisions shall be taken to protect personnel from electricshock when ?oors are wet. Exception: Wood ?oors laiddirectly on concrete shall not be required to be wetted.6.1.4.2Nearby Openings.All cracks or openingsin the ?oor shall be covered or closed or precautions shallbe taken to protect ?ammable or combustible materialson the ?oor below from sparks which might drop throughthe openings. The same precautions shall be observedwith regard to cracks or openings in walls, opendoorways, or open or broken windows.6.2Fire Protection

6.2.1Extinguishers and Sprinklers

6.2.1.1Suf?cient ?re extinguishing equipmentshall be ready for use where welding and cutting work isbeing done. Permissible ?re extinguishing equipmentshall be pails of water, buckets of sand, hose, or portableextinguishers, depending upon the nature and quantity ofcombustible material exposed.

6.2.1.2Where sprinkler system protection exists, itshall remain operable during the welding or cutting.Automatic sprinkler heads in the immediate vicinity ofthe welding shall be permitted to be temporarily shieldedwith noncombustible sheet material or damp cloth guardswhere they could be activated by the heat of the weldingprocess.

6.2.2Fire Watchers.Fire watchers shall be quali?edindividuals, knowledgeable about ?re reporting procedures,and emergency rescue procedures, who are assigned dutiesto detect and prevent spread of ?res. Fire watchers shall beposted where welding or cutting is done and where a large?re might develop, or whenever any of the followingconditions exist:

(1)Proximity of Combustibles.Combustible materialsin building construction or contents are closer than aradius of 35 feet (10.7 meters) to the point of operation.(2)Openings.There are wall or ?oor openings withina radius of 35 feet (10.7 meters) which expose combustible

E6.2.2Fire watchers are persons assigned to workwith welders, to watch for ?res resulting from welding,cutting, and brazing operations. When welding or cuttingat elevated positions, care should be taken to protectagainst falling sparks and spatter. Accumulations of dustmay be ignited by sparks or spatter, and carry a ?re toother locations.

Fire watchers normally would watch for ?res in areas notreadily observed by the welder, such as on opposite sidesof walls, levels below, or hidden areas, or to observe in anarea after the welder has left.

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material in adjacent areas, including concealed spaces inwalls, ceilings or ?oors.

(3)Metal Walls and Pipes.Combustible materialsadjacent to the opposite side of metal partitions, walls,ceilings, or roofs, or in contact with pipes, and are likelyto be ignited by conduction or radiation.

(4)Ship Work.Ship work performed on opposite sidesof tank shells, decks, overheads, and bulkheads, wheredirect penetration of sparks or heat transfer in weldingmay introduce a ?re hazard to an adjacent compartment.6.2.3Additional Fire Watchers.Where it isnecessary to observe areas that are hidden from the viewof a single ?re watcher (other side of partitions, walls,ceilings, etc.) additional ?re watchers shall be posted.6.2.4 Fire Watch Duties.Fire watchers shall betrained in the use of ?re extinguishing equipment. Theyshall be familiar with facilities for sounding an alarm inthe event of a ?re, and shall remain outside of anycon?ned space to be in communication with thoseworking inside.

They shall watch for ?res in all exposed areas, try toextinguish them only when obviously within the capacityof the equipment available, or otherwise sound the alarm.A ?re watch shall be maintained for at least one-half hourafter completion of welding or cutting operations todetect and extinguish possible smoldering ?res. Firewatchers shall be permitted to have additional duties;however, these additional duties shall not distract themfrom their ?re watcher responsibilities.

6.3Hot-Work Authorization.Before welding orcutting is begun in a location not designed for suchpurposes, inspection and authorization by a designatedmanagement representative shall be required.

6.4Welding or Cutting Containers.Welding orcutting work shall not be started until the container hasbeen prepared for hot work. Workers shall be fullyfamiliar with AWS F4.1, Safe Practices for thePreparation of Containers and Piping for Welding andCutting, prior to the commencement of hot work.

Processes such as air carbon arc cutting and plasma arccutting can cause sparks to travel in excess of 35 feet(10.7 meters).

In Canada, the recommended distance is 50 feet (15 meters).

E6.2.4The duration of ?re watch should be extendeduntil the hazard of ?re no longer exists. Be alert,combustibles such as wood dust can smolder for extendedperiods of time (days). See NFPA Fire ProtectionHandbook,20th edition, clause 9, page 5.

E6.3Hot work is any work involving burning, welding, orsimilar operations capable of initiating ?res or explosions.Authorization is usually in the form of a written permit.See NFPA 51B for an example of a hot-work permit.E6.4All containers should be considered unsafe forwelding or cutting unless they have been rendered safe,or declared safe by a quali?ed person. When welding orcutting containers, there is the possibility of explosions,?res, and the release of toxic vapors or fumes. Containersinclude jacketed vessels, tanks, drums, covered parts orother equivalent situations. Seemingly empty containersmight have materials hidden in cracks and crevices,which will release hazardous fumes when heated bywelding or cutting. By-products of corrosion can result inexplosive atmospheres (hydrogen) in a container. Even awater tank should be considered hazardous unless aquali?ed person has declared it safe to weld or cut.Information on preparing containers that have held haz-ardous substances can also be found in NFPA 326,Standard for the Safeguarding of Tanks and Containersfor Entry, Cleaning, or Repair, and several API docu-ments. See Annexes B and C for details.

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7.Con?ned Spaces

7.1Ventilation in Con?ned Spaces.Ventilation incon?ned spaces shall be suf?cient to assure adequateoxygen for life support, to prevent accumulation ofasphixiants or ?ammable or explosive mixtures, toprevent oxygen-enriched atmospheres, and to keepairborne contaminants in breathing atmospheres belowallowable limits, as referred to in 5.1.

7.1.1Ventilation Before Entry.Con?ned spaces shallnot be entered unless they are well ventilated and tested toassure they are safe for entry. When it is not practical tomaintain the space safe for entry, the space shall only beentered when the following conditions are met:

(1)the space has been tested and determined not topresent an oxygen de?cient or oxygen enriched atmos-phere, a hazard of ?re or explosion, or an atmospherehazardous to life;

(2)a trained second person equipped for rescue ispresent outside the con?ned space.

7.1.2Testing Atmospheres.Con?ned spaces shallbe tested for toxic or ?ammable gases, dusts, and vapors,and for adequate or excess oxygen before entering andduring occupancy. The same precautions shall apply toareas such as pits, tank bottoms, low areas, and areas near?oors when heavier than air gases and vapors are present,and to areas such as tank tops, high areas and nearceilings when lighter than air gases are present.7.1.3Adjacent Persons.Adequate ventilation incon?ned spaces shall be assured not only to protectwelders or cutters themselves, but to protect all personnelwho may be present in the area.

7.1.4Air Quality and Quantity.The quality andquantity of air for ventilation shall be such that personnelexposures to hazardous contaminants are maintainedbelow the allowable limits speci?ed in 5.1. Breathing airsupplied by cylinders or compressors shall meet theGrade D requirements of ANSI/CGA G-7.1.

The supply air line for respirators shall be a dedicated linethat is not capable of being valved to any other line whichcould allow hazardous or toxic gases into the respiratorair line.

7.1.5Prohibited Ventilation Gases.Oxygen, or anyother gas or mixtures of gases, except air, shall not beused for ventilation.

7.1.6Ventilation in Areas Immediately Dangerousto Life or Health (IDLH).When welding, cutting, orrelated processes are performed in areas immediatelydangerous to life or health, the requirements of OSHA 29CFR 1910.146 shall be followed.

E7.1.5Air may be natural air or synthesized air forbreathing purposes.

E7.1.6See 7.5.1 for information on attendantresponsibilities.

E7.1.4Additional information on air quality forrespirators and their use can be found in 29 CFR 1910.134.E7.1Work in con?ned spaces requires special precautions.Workers, including both owner and contractor personnel,should be familiar with written con?ned space workprogram guidelines or should have the work supervised bya trained person. Asphyxiation causes unconsciousnessand death without warning. Oxygen enriched atmospheresgreatly intensify combustion, and may rapidly cause severeand often fatal burns.E7.1.1See 7.5.

E7.1.2See ANSI Z117.1 and OSHA 29 CFR 1910.146for further precautions. If possible, a continuousmonitoring system with audible alarms should be used forcon?ned space work. Gases such as argon, propane andcarbon dioxide are heavier than air. Gases such as heliumand natural gas are lighter than air.

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7.2Location of Service Equipment

E7.2The purpose of this provision is to preventcontamination of the atmosphere of a con?ned space bypossible leaks from gas cylinders or fumes from weldingpower sources or similar equipment and to minimize thepossibility of electric shock.

7.2.1Compressed Gas Cylinders and WeldingPower Sources.When welding or cutting in con?nedspaces, gas cylinders and welding power sources shall belocated outside the con?ned space.

7.2.2Heavy Portable Equipment on Wheels.Heavy portable equipment mounted on wheels shall besecured in position to prevent accidental movementbefore operations are started in a con?ned space. See3.1.3 for additional information.

7.2.3Ventilation Ducts.Ducts used to provide localexhaust ventilation for welding, cutting, or relatedoperations shall be constructed of noncombustiblematerials. These ducts shall be inspected as necessary toinsure proper function and that the internal surfaces arefree of combustible residuals.

7.3Adjacent Areas.When welding or cutting is to bedone over, or adjacent to, any con?ned space, personnelshall be made aware of the hazards in the con?ned spaceand shall not enter such spaces without ?rst following theprecautions speci?ed in ANSI Z117.1 and OSHA 29 CFR1910.146.

7.4Emergency Signal.When a person enters a con?nedspace through a manhole or other small opening, meansshall be provided for signaling outside personnel for helpas speci?ed in OSHA 29 CFR 1910.146.

7.5Attendants in Areas Immediately Dangerous toLife or Health (IDLH).When operations are carried onin con?ned spaces where atmospheres immediatelydangerous to life or health may be present or maydevelop, attendants shall be stationed on the outside ofthe con?ned space as speci?ed in OSHA 29 CFR1910.146.

7.5.1Attendants Responsibilities.Attendants shallhave a preplanned rescue procedure for quickly removingor protecting those working inside in case of emergency,shall observe the workers inside or be in constantcommunication with them, and shall be capable of puttingrescue operations into effect. Positive pressure, self-contained breathing apparatus shall be available for eachattendant required to enter as a rescuer or ?rst responder.7.5.2Body Harness Systems.When body harnesssystems are used for emergency rescue purposes, theyshall be attached to the person’s body so that they do notbecome obstructed in passing through a small or tortuousexit path in following the preplanned rescue procedure.

E7.5.1Rescue operations should take intoconsideration such elements as the number of workersrequiring rescue, the time available to perform the rescuegiven different accident scenarios, and the time neededfor additional rescue personnel to be summoned.E7.2.3When welding or cutting activities occur nearventilation ducts, or conveyor systems, care should betaken to see that sparks and spatter are not carried tolocations with combustible or explosive material.

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7.6Brazing Furnaces

E7.6Brazing furnaces are in many respects a type ofcon?ned space. These employ a variety of atmospheres to exclude oxygen during the brazing process. Suchatmospheres may include inert gas, ?ammable gas,?ammable gas combustion products, or vacuum. Thefollowing are potential hazards in the operation ofbrazing furnaces:

(1)asphyxiation of personnel entering or working inadjacent areas where there is insuf?cient oxygen in theatmosphere to support life;

(2)development of explosive mixtures of ?ammablegas and air within the furnace during generation or vent-ing of atmosphere within the furnace;

(3)accumulation of hazardous fumes or gases in thework area due to the brazing process.

7.6.1Life Support.If brazing furnaces requirepersonnel entry into the furnace or adjacent areas, theprovisions of 7.1 shall be observed.

7.6.2Fire and Explosion.If brazing furnaces utilizea ?ammable gas for their interior atmosphere, or if a?ammable gas is burned to create an interior atmosphere,procedures shall be followed which will assure that anexplosive mixture of ?ammable gas and air is notproduced in the furnaces.

7.6.3Venting.Venting of the atmosphere fromwithin brazing furnaces shall be exhausted to a locationwhere it will not expose personnel to hazard.

8.Public Exhibitions andDemonstrations

8.1Application.All requirements of the standard shallapply to public exhibitions and demonstrations, exceptwhen superseded by this section.

E8.Refer to NFPA 51B. Local codesand regulations may requireadditional measures.

E8.1This section contains safety precautions speci?c towelding and cutting performed at public demonstrationsand exhibits, displays, and trade shows (referred tohereinafter as the site) to ensure the protection of viewers,demonstrators, and the public.

8.2Supervision.Installation and operation of welding,cutting, and related equipment shall be done by, or underthe supervision of, a quali?ed person.8.3Site

8.3.1Site Design.The site shall be constructed,equipped, and operated so as to minimize the possibilityof injury to viewers at the site.

8.3.2Site Location.Materials and equipment on thesite shall be located so as not to interfere with evacuationof people during an emergency.

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8.4Fire Protection

8.4.1Extinguishers.Sites shall be provided withportable ?re extinguishers of appropriate size and type.8.4.2Combustibles.Combustible materials at thesite shall be shielded from ?ames, sparks, and moltenmetal.

8.4.3Fire Department.The ?re department shall benoti?ed in advance of such use of the site.8.5Protection of the Public

8.5.1Flames, Flying Sparks, and Molten Metal.The public shall be shielded from ?ames, ?ying sparks,and molten metal.

8.5.2Radiation.The public shall be shielded fromharmful ultraviolet, infrared, and other electromagneticradiation. Shielding shall protect direct viewers andadjacent passersby.

8.5.3Fumes and Gases.The public shall beprotected from inhalation of hazardous concentrations offumes and gases.

8.5.4Electrical Shock.The public shall be protectedfrom contact with live electrical parts.8.6Cylinders

8.6.1Capacity.Cylinders shall not be charged inexcess of one-half their maximum permissible capacityby weight or pressure. Cylinders of non lique?ed gasesand acetylene shall be charged to not more than one-halftheir maximum permissible charged pressure in psig(kPa). Cylinders of lique?ed gases shall be charged to notmore than one-half the maximum capacity in pounds(kilograms).

8.6.2Storage.Unconnected cylinders, stored at thesite, shall be limited to approximately one day’sconsumption of each gas used. Other cylinders shall bestored in an approved storage area, preferably outdoorsbut not near a building exit.

8.6.3Trucks.When transported, cylinders weighingmore than 40 pounds (18 kilograms), shall be carried on ahand or motorized truck.

8.6.4Cylinder Valves.Cylinder valves shall beclosed when equipment is unattended.

8.6.5Valve Caps.Where cylinders are designed to beequipped with valve protection caps, the caps shall be inplace except when the cylinders are in service orconnected ready for service.

8.6.6Protection.Cylinders shall be located orsecured so that they cannot be knocked over.

E8.4See also clause 6, Fire Prevention and Protection.

E8.5See also clause 6, Fire Prevention and Protection.

E8.6See also 10.8 and 10.9.

E8.6.4Cylinder valves should be closed and cappedwhen equipment is unattended for an extended time, suchas for several days. See 8.6.5.

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8.7Process Hoses, Cables, and Conduits

8.7.1Physical Damage.Hoses, cables, and conduitsshall be located and protected so that they will not bephysically damaged.

8.7.2Tripping.Hoses, cables, and conduits shall belocated and protected to minimize tripping hazard.

E8.7See also 10.6.

9.Precautionary Information

9.1General.Personnel shall be informed of thepotential hazards from fumes, gases, electric shock, heat,radiation, and noise.

9.2Precautionary Information for Arc Welding andRelated Processes and Equipment.The informationshown in Figure 1, or its equivalent, shall be placed onstock containers of materials such as wires, ?uxes, andelectrodes and on major equipment such as powersupplies, wire feeders, and controls used in arc welding,arc cutting, and allied processes. The information shall bereadily visible and may be on a label, tag, or other printedform.

Where noise has been determined to be a hazard, thestatement of hazard, “NOISE can damage hearing,” shallbe placed after the statement of hazard, “ELECTRICSHOCK can KILL.”

When provided, ?rst aid information shall follow the lastprecautionary measure.

The company name and address shall appear on the labelunless it is readily visible elsewhere on the product.9.3Precautionary Information for Oxyfuel GasProcesses and Equipment.As a minimum, theinformation shown in Figure 2, or its equivalent, shall beplaced on stock containers of materials such as rods and?uxes, and on major equipment used in oxyfuel gaswelding, cutting, and allied processes. The informationshall be readily visible and may be on a label, tag, or otherprinted form.

Where noise has been determined to be a hazard, thestatement of hazard, “NOISE can damage hearing” shallbe placed after the statement of hazard, “HEAT RAYS(INFRARED RADIATION) from ?ame or hot metal caninjure eyes.” This information shall follow the last pre-cautionary measure. The company name and addressshall appear on the label unless it is readily visible else-where on the product.

9.4Hazardous Materials Information.When the fumefrom a product contains a by-product component whoseallowable limit will be exceeded before the generalwelding fume allowable limit, the by-product component

E9.4A number of potentially hazardous materials areemployed in the ?uxes, coatings, coverings, and ?llermetals used in welding and cutting, or are released to theatmosphere during welding and cutting. Material SafetyE9.3See comment for 9.2. Some processes are arclessand ?ameless. Modify the information in Figure 2 tore?ect the proper heat source and appropriate hazards.E9.1Refer to clause 4, Protection of Personnel and theGeneral Area, for additional information on potentialhazards. See also OSHA 29 CFR Section 1910.1200.E9.2This information is a minimum requirement.Additional information and labeling may be required byother standards and regulations. The message is theimportant thing. This information is intended to get it tothe ?nal user. See also the ANSI Z535 series of standardson safety signs and colors.

First aid information is generally recommended only onproducts that present immediate and major health hazards.A label identi?cation number should appear on the label.When materials are determined to be more hazardous thanthose requiring the use of WARNING as a signal word,the signal word should be changed to DANGER and anappropriate precautionary message should be added.

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WARNING:PROTECT yourself and others. Read and understand thisinformationFUMES AND GASES can be hazardous to your health.ARC RAYS can injure eyes and burn skin.ELECTRIC SHOCK can KILL.?Before use, read and understand the manufacturer’sinstructions, Material Safety Data Sheets (MSDSs),and your employer’s safety practices.?Keep your head out of the fumes.?Use enough ventilation, exhaust at the arc, or both, tokeep fumes and gases from your breathing zone andthe general area.?Wear correct eye, ear, and body protection.?Do not touch live electrical parts.?See American National Standard Z49.1, Safety inWelding, Cutting, and Allied Processes, published bythe American Welding Society, 550 NW LeJeuneRoad, Miami, FL 33126; OSHA Safety and HealthStandards, available from the U.S. GovernmentPrinting Of?ce.DO NOT REMOVE THIS INFORMATIONWARNING:PROTECT yourself and others. Read and understand thisinformation.FUMES AND GASES can be hazardous to your health.HEAT RAYS (INFRARED RADIATION) from ?ame orhot metal can injure eyes.?Before use, read and understand the manufacturer’sinstructions, Material Safety Data Sheets (MSDSs),and your employer’s safety practices.?Keep your head out of the fumes.?Use enough ventilation, exhaust at the ?ame, or both,to keep fumes and gases from your breathing zone andthe general area.?Wear correct eye, ear, and body protection.?See American National Standard Z49.1, Safety inWelding, Cutting, and Allied Processes, published bythe American Welding Society, 550 NW LeJeuneRoad, Miami, FL 33126; OSHA Safety and HealthStandards, available from the U.S. GovernmentPrinting Of?ce.DO NOT REMOVE THIS INFORMATIONFigure 1—Precautionary Information forArc Welding Processes and Equipmentshall be identi?ed on the Material Safety Data Sheet(MSDS). These include, but shall not be limited to, by-products of the materials itemized in 5.5.1.

9.5Brazing Filler Metals Containing Cadmium.As aminimum, brazing ?ller metals containing cadmium as adesignated constituent shall carry the information shownin Figure 3, or its equivalent, on tags, boxes, or othercontainers, and on any coils of wire not supplied to theuser in a labeled container.

9.6Brazing and Gas Welding Fluxes ContainingFluorides.As a minimum, brazing and gas welding?uxes containing ?uorine compounds shall haveprecautionary information as shown in Figure 4, or itsequivalent, on tags, boxes, or other containers to indicatethat they contain ?uorine compounds.

9.7Material Safety Data Sheets (MSDSs).Thesuppliers of welding materials shall provide a MaterialSafety Data Sheet which identi?es the hazardous materials,if any, used in their welding and cutting products.

Figure 2—Precautionary Information forOxyfuel Gas Processes and EquipmentData Sheets (MSDSs) are required by federal regulations.See also 9.7.E9.5See E9.3.

E9.6See E9.3.

E9.7MSDSs are required by OSHA 29 CFR Section1910.1200.

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DANGER: Contains cadmium. Protect yourself and others. Read and understand thisinformation.FUMES ARE POISONOUS AND CAN KILL.?Before use, read and understand the manufacturer’sinstructions, Material Safety Data Sheets (MSDSs),and your employer’s safety practices.?Do not breathe fumes. Even brief exposure to highconcentrations should be avoided.?Use enough ventilation or exhaust, or both, to keepfumes and gases from your breathing zone and thegeneral area. If this cannot be done, use air suppliedrespirators.?Keep children away when using.?See American National Standard Z49.1, Safety inWelding, Cutting, and Allied Processes, published bythe American Welding Society, 550 NW LeJeuneRoad, Miami, FL 33126; OSHA Safety and HealthStandards, available from the U.S. GovernmentPrinting Of?ce.First Aid:If chest pain, shortness of breath, cough, or feverdevelops after use, obtain medical help immediately.DO NOT REMOVE THIS INFORMATIONWARNING: Contains ?uorides.Protect yourself and others. Read and understand thisinformation.FUMES AND GASES CAN BE HAZARDOUS TOYOUR HEALTH. BURNS EYES AND SKIN ON CON-TACT. CAN BE FATAL IF SWALLOWED.?Before use, read and understand the manufacturer’sinstructions, Material Safety Data Sheets (MSDSs),and your employer’s safety practices.?Keep your head out of the fume.?Use enough ventilation or exhaust, or both, to keepfumes and gases from your breathing zone and thegeneral area.?Avoid contact of ?ux with eyes and skin.?Do not take internally.?Keep children away when using.?See American National Standard Z49.1, Safety inWelding, Cutting, and Allied Processes, published bythe American Welding Society, 550 NW LeJeuneRoad, Miami, FL 33126; OSHA Safety and HealthStandards, available from the U.S. GovernmentPrinting Of?ce.First Aid:If contact in eyes, ?ush immediately with waterfor at least 15 minutes. If swallowed, induce vomiting.Never give anything by mouth to an unconscious person.Call a physician.DO NOT REMOVE THIS INFORMATIONFigure 3—Precautionary Information forBrazing Filler Metals Containing CadmiumFigure 4—Precautionary Information forBrazing and Gas Welding FluxesContaining FluoridesE9.8See also ANSI Z535 and NEMA EW6, Guidelinesfor Precautionary Labeling for Arc Welding and CuttingProducts.

9.8Graphic Symbols.Graphic symbols shall bepermitted in place of text when they present equivalentprecautionary information.

9.9Hazard Communications.Employers shall assurethat the information described in this section iscommunicated to end users of the products (see 3.2.1.2 ofthis standard).

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Part II

Speci?c Processes

10.Oxyfuel Gas Welding and Cutting

Safety

10.1Scope.This section covers safe practices for usersof oxyfuel gas welding, cutting, soldering, brazing, andrelated materials and equipment. It does not coverspeci?cations for the design and construction of suchequipment, nor for the construction or installation of bulkgas supply or piping distribution systems.10.2Terminology

10.2.1Call Oxygen by Name.Oxygen shall be calledby its proper name, oxygen, and not by the word “air.”10.2.2Call Fuel Gases by Name.Fuels, fuel gases,and liquid fuels shall be called by their proper names,such as, acetylene, propane, natural gas, and not by theword “gas.”

10.3Oxygen and Combustibles

10.3.1Keep Oxygen from Combustibles.Oxygencylinders, cylinder valves, couplings, regulators, hoses,and apparatus shall be kept free from oil, grease, andother ?ammable or explosive substances. Oxygencylinders or apparatus shall not be handled with oilyhands or gloves.

10.3.2Prohibited Uses for Oxygen.Oxygen shallnot be used as a substitute for compressed air. Oxygenshall not be used in pneumatic tools, in oil preheatingburners, to start internal combustion engines, to blow outpipelines, to dust clothing or work, or to create pressurefor ventilation or similar applications. Jets of oxygenshall not be permitted to strike an oily surface, greasyclothing, or enter fuel oil or other storage tanks.10.3.3xygen Equipment.Oxygen cylinders,equipment, pipelines, or apparatus shall not be usedinterchangeably with any other gas.

10.4Attachments for Gas Mixing.No device orattachment facilitating or permitting mixtures of air oroxygen with ?ammable gases prior to consumption,except at a burner or in a torch, shall be allowed unlessapproved for the purpose.10.5Torches

10.5.1 Approval.Only approved torches, as de?nedin 2.1, shall be used.

E10.5.1For additional information on torches, seeCGA E-5, Torch Standard for Welding and Cutting.E10.3.1Oxygen will not burn, but vigorously supportsand accelerates combustion, causing materials to burnwith great intensity. Oil or grease in the presence ofoxygen may ignite readily and burn violently.

E10.2.1Use of this proper name will decrease theprobability of misuse.

E10.2.2Proper identity is needed to determine thecorrect hazards.

E10.1Note that this applies to USERS, notmanufacturers of equipment. See 1.3.

E10.3.2These prohibitions decrease the possibility ofa raging oxygen-fed ?re occurring. Oxygen is not?ammable, but vigorously supports combustion. Oxygencan be adsorbed by clothing. A slight spark can result insevere burns.

E10.3.3Contamination of oxygen equipment withcombustible substances may lead to spontaneouscombustion or explosion in oxygen.

E10.4This prevents the accumulation of explosivemixtures.

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10.5.2Operation

10.5.2.1Leak Testing Connections.Connectionsshall be checked for leaks after assembly and beforelighting the torch. Flames shall not be used.

E10.5.2.1Leak test solutions for use on oxygenconnections are commercially available and arerecommended. Leak testing should be repeated after theequipment has been used in a manner that could causeleaks.

E10.5.2.2Purging consists of allowing each gas to?ow through its respective hose separately, to purge outany ?ammable mixture in the hose. It is important topurge before lighting the torch.

E10.5.2.3This is to minimize burns of hands and?ngers. Do not attempt to light or relight torch from hotmetal in a small cavity, hole, furnace, etc., where gasmight accumulate. Point the torch away from persons orcombustible materials.

10.5.2.2Purging Hoses.Before lighting the torchfor the ?rst time each day, hoses shall be purgedindividually. Hoses shall not be purged into con?nedspaces or near ignition sources. Hoses shall be purgedafter a cylinder change.

10.5.2.3Lighting Torch.A friction lighter,stationary pilot ?ame, or other suitable source of ignitionshall be used. Matches, cigarette lighters, or welding arcs,shall not be used for lighting torches.

Manufacturers’ procedures shall be followed with respectto the sequence of operations in lighting, adjusting, andextinguishing torch ?ames.

10.5.2.4Con?ned Space.In con?ned spaces, thetorch valves shall be closed and in addition, the fuel gasand oxygen supply to the torch shall be positively shut offat a point outside the con?ned area whenever the torch isnot to be used, such as during lunch or overnight.Unattended torches and hoses shall be removed from thecon?ned space.

10.6Hose and Hose Connections

10.6.1Speci?cation.Hose for oxyfuel gas serviceshall comply with the Rubber Manufacturers AssociationIP-7 Speci?cation for Rubber Welding Hose.

E10.5.2.4This is to minimize the possibility of gasaccumulation in con?ned space due to leaks orimproperly closed valves when gas welding or cutting iscompleted. See also clause 7, Con?ned Spaces, of thisstandard, for other precautions to be observed in workingin con?ned spaces.

E10.6.1Metal-Clad or armored hose is notrecommended. However, as part of a machine or anappliance when conditions of use make metal reinforcingadvantageous, hose may be used in which such metalreinforcing is exposed to neither the inside gases nor theoutdoor atmosphere.

E10.6.2The generally recognized colors in the UnitedStates are red for fuel gas hose, green for oxygen hose,and black for inert-gas and air hose. Other countriessometimes use different colors. International colorsgenerally recognized are described in ISO 3821,Welding—Rubber Hoses for Welding, Cutting, and AlliedProcesses.

E10.6.3This leaves 2/3 of the hoses visible for coloridenti?cation, and provides adequate ventilation toprevent gas entrapment in the event of hose leaks.

10.6.2Colors.Hoses for oxyfuel gas service shall becolor coded according to the authorities havingjurisdiction.

10.6.3Taping.When parallel lengths of oxygen andfuel gas hose are taped together for convenience and to prevent tangling, not more than 4 inches (100millimeters) in each 12 inches (300 millimeters) shall becovered by tape.

10.6.4Maintenance.Hose showing leaks, burns,worn places, or other defects rendering it un?t for serviceshall be repaired or replaced.

E10.6.4Frequency of inspection depends upon theamount and severity of use. Bending areas at theregulator and torch connections are prone to crack andleak because of additional stress.

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10.6.5Hose Connection Speci?cations.Hoseconnections shall comply with the standard hoseconnection speci?cation, CGA Pamphlet E-1, RegulatorConnection Standards.

Hose connections for welding gas lines shall not be com-patible with connections for breathing air.

10.6.6Hose Connection Quality.Hose connectionsshall be fabricated in a manner that will withstand,without leakage, twice the pressure to which they arenormally subjected in service, but in no case less than 300 psi (2070 kPa). Oil-free air or an oil-free inert gasshall be used for testing.

10.6.7Devices. Only approved devices as de?ned in2.1 shall be used in oxyfuel gas systems.

E10.6.7When an approved device such as a hosecheck valve or ?ash-back arrestor is used in an oxyfuelgas welding and cutting torch system, the device shouldbe used and maintained in accordance with themanufacturers’ instructions. Refer to CGA Pamphlet E-2,Standard Hose Connection Speci?cations.

E10.6.7.1Flashback arrestors can provide a certainmeasure of protection against the hazards of ?ashback.To maintain this protection and to ensure that they havenot become damaged or inoperative during use, a routineinspection program should be followed as speci?edduring use. Also, a regular inspection program should befollowed as speci?ed in the instructions provided by themanufacturer.

Many years of ?eld experience has shown various oxy-fuel gas torches to be reliable and safe apparatus whenoperated in accordance with instructions recommendedby the manufacturer. Under certain circumstances, theuser’s failure to follow these instructions can cause theback?ow (reverse ?ow) of unwanted gas and/or ?ashbackinto the upstream equipment.

10.7Pressure-Reducing Regulators

10.7.1Approval.Only approved pressure reducingregulators, as de?ned in 2.1, shall be used.

10.7.2Designated Service.Pressure reducingregulators shall be used only for the gas and pressures forwhich they are labeled. The regulator inlet connectionsshall comply with ANSI/CGA Standard V-1, Standardfor Compressed Gas Cylinder Valve Outlet and InletConnections.

Regulators shall not be interchanged among designatedgas services.

10.7.3Inspection Before Use.Union nuts andconnections on regulators shall be inspected before use todetect faulty seats which may cause leakage when theregulators are attached to cylinder valves or hoses.Damaged nuts or connections shall be replaced.

E10.7.1Refer to CGA E-4, Standard for GasRegulators for Welding and Cutting.

E10.7.2Contamination can lead to explosions and ?re.

10.6.7.1The use of suitable approved ?ashbackarrestors shall be permitted.

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10.7.4Oxygen Gauges.Gauges used for Oxygenservice shall be marked “USE NO OIL.”

10.7.5Oxygen Regulators.Regulators shall bedrained of oxygen before they are attached to a cylinderor manifold, or before the cylinder valve is opened (seealso 10.8.4.4 and 10.8.4.11). Oxygen cylinder ormanifold valves shall always be opened slowly (see10.8.4.3 and 10.8.4.4).

E10.7.5The regulator attached to a cylinder can bedrained of oxygen by momentarily opening and thenclosing the downstream line to the atmosphere with theregulator adjusting screw engaged and the cylinder valveclosed. The cylinder valve is then opened slowly. Theoxygen cylinder or manifold outlet connection should bewiped clean with a clean cloth, free of oil and lint, and thecylinder valve “cracked” before connecting the regulator.(See 10.8.4.3.)

These steps help reduce the chance of oxygen fed regula-tor ?res when the regulator is pressurized from a high-pressure source.

10.7.6Maintenance.When regulators or parts ofregulators, including gauges, need repair, the work shallbe performed by quali?ed mechanics.

10.8Compressed and Oxyfuel Gas Cylinders(Containers)

E10.8Compressed gas cylinders used in welding andcutting processes contain gases generally at pressuresapproximately 2500 psi (17237 kPa), but sometimesmuch higher. Gases at these pressures are dangerous ifnot properly handled. The procedures described in thissection are intended to prevent damage or abuse to gascylinders which might cause them to leak or explode withthe consequence of serious damage, injury, or death.

10.8.1General Cylinder Provisions

10.8.1.1Approval.All portable cylinders used forstorage and shipment of compressed gases shall beconstructed and maintained in accordance with 49 CFR173 regulations of the U.S. Department of Transportation(DOT).

10.8.1.2Filling Authorization.No one except theowner of the cylinder or person authorized by the ownershall ?ll a cylinder.

10.8.1.3Mixing Gases.No person other than thegas supplier shall mix gases in a cylinder or trans?ll gasesfrom one cylinder to another.

10.8.1.4Content Identi?cation.Compressed gascylinders shall be legibly marked with either the chemicalor the trade name of the gas in conformance withANSI/CGA C-7, Guide to Preparation of PrecautionaryLabeling and Marking of Compressed Gas Containers,for the purpose of identifying the gas content. Cylinderson which the labeling is missing or illegible shall not beused. They shall be returned to the supplier.

10.8.1.5Changing Markings.The numbers andmarkings stamped into cylinders shall not be changedexcept in conformance with 49 CFR 173 U.S. DOTregulations.

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10.8.1.6Connection Threads.Compressed gascylinders shall be equipped with connections complyingwith ANSI/CGA V-1, Standard for Compressed GasCylinder Valve Outlet and Inlet Connections.

10.8.1.7Valve Protection.All cylinders with awater weight capacity over 30 pounds (13.6 kilograms)shall be equipped with a means of connecting a valveprotection cap or with a collar or recess to protect thevalve.

10.8.1.8Cylinder Temperature.The storagetemperature of the cylinder contents shall not be allowedto exceed 125°F (52°C). The use temperature shall notexceed 120°F (49°C).

10.8.1.9Damaged Cylinders.Cylinders evidencingsevere damage, corrosion, or ?re exposure shall not be used.10.8.2Cylinder Storage

10.8.2.1Protection.Cylinders shall be storedwhere they will not be exposed to physical damage,tampering, or subject to temperatures which would raisethe contents above the limits of 10.8.1.8.

Cylinders shall be stored away from elevators, stairs, organgways in assigned places where cylinders will not beknocked over or damaged by passing or falling objects.Cylinders shall be secured in storage to prevent falling.10.8.2.2Cylinders Separated from Combustibles.Cylinders in storage shall be separated from ?ammable andcombustible liquids and from easily ignited materials suchas wood, paper, packaging materials, oil, and grease by atleast 20 feet (6.1 meters), or by a noncombustible barrier at least 5 feet (1.6 meters) high having a ?re resistance of atleast one-half hour.

10.8.2.3Oxygen Separated from Fuel Gas.Oxygen cylinders in storage shall additionally beseparated from fuel gas cylinders, or from reserve stocksof calcium carbide, by a distance or barrier as describedin 10.8.2.2.

10.8.2.4Oxygen in Acetylene GeneratorBuildings.Oxygen cylinders stored in outside acetylenegenerator houses shall be separated from the generator orcarbide storage rooms by a noncombustible partitionhaving a ?re resistance of at least one hour. This partitionshall be without openings and shall be gas-tight.Oxygen shall not be stored inside acetylene generatorrooms.

10.8.2.5Fuel Gas Cylinders Upright.Acetyleneand lique?ed gas cylinders shall be used valve end up.10.8.2.6Fuel Gas Storage Limits.Fuel gasstorage limits shall be in accordance with NFPA 51,

E10.8.2.5This prevents liquid ?ow into hoses andregulators.

E10.8.2.1Check for overhead combustibles suchas overhead lines and piping, suspended ceilingmaterials, etc., when considering storage location. Thestorage location should be well ventilated so as to avoidthe accumulation of hazardous gases in the event ofcylinder leakage.

E10.8.1.8Hot gases mayexpand and increasepressures above allowable limits. For additionalinformation, contact the Compressed Gas Association.

E10.8.2.2Heat can cause pressure to rise and maylead to cylinder rupture or operation of protective devices.

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Standard for the Design and Installation of Oxygen-FuelGas Systems for Welding, Cutting, and Allied Processes.10.8.3Cylinder Handling

10.8.3.1Rough Handling.Cylinders shall not bedropped, struck, or permitted to strike objects violently ina manner which may damage the cylinder, valve, or safetydevice.

10.8.3.2Pry Bars.Bars shall not be used undervalves or valve protection caps to pry cylinders loosewhen frozen to the ground or otherwise ?xed.

10.8.3.3Rollers or Supports.Cylinders shallnever be used as rollers or supports, whether full or empty.10.8.3.4Safety Devices.Safety devices shall notbe tampered with.

10.8.3.5Closed Valves.Cylinder valves shall beclosed before moving cylinders.

10.8.3.6Valve Protection Caps.Valve protectioncaps, where the cylinder is designed to accept a cap, shallalways be in place and handtight (except when cylindersare in use or connected for use).

10.8.3.7Manual Lifting.Valve protection capsshall not be used for lifting cylinders.

10.8.3.8Lifting Equipment.When transportingcylinders by a crane or derrick, a cradle or suitableplatform shall be used. Slings or electromagnets shall notbe used for this purpose.

10.8.3.9Transporting Cylinders.When cylindersare transported by motor vehicle, they shall be securedand transported in accordance with Department ofTransportation regulations, when required.

10.8.3.10Cylinders with Regulators Attached.When cylinders are to be moved with regulators attached,the cylinders shall be secured in position when moved,and cylinder valve closed.10.8.4Cylinder Use

10.8.4.1Pressure Regulator.Compressed gasshall never be used from cylinders without reducing thepressure through a suitable regulator attached to thecylinder valve or manifold, unless the equipment used isdesigned to withstand full cylinder pressure.

10.8.4.2Maximum Acetylene Pressure.Acetylene shall not be utilized at a pressure in excess of15 psig (103 kPa) or 30 psia (206 kPa). This requirementshall not apply to storage of acetylene dissolved in asuitable solvent in cylinders manufactured andmaintained according to Department of Transportationrequirements, or to acetylene for chemical use.

E10.8.4.2Acetylene can dissociate (decomposewith explosive violence) above these pressure limits.The 30 psia (206 kPa) limit is intended to prevent unsafeuse of acetylene in pressurized chambers such as cais-sons, underground excavations, or tunnel construction.E10.8.3.9It is especially hazardous to transportcylinders of fuel gas inside any vehicle, such as anautomobile, where gas from a leak can accumulate insidethe passenger compartment or trunk. Opening the door ortrunk will activate a light switch that acts to ignite theaccumulated gas and cause a deadly explosion.

E10.8.3.6Cylinder valve protection caps should bekept with the cylinders so they can be reassembled whenthe regulator is removed.

E10.8.3.2The use of warm (not boiling) water isrecommended.

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10.8.4.3“Cracking” Cylinder Valve.Beforeconnecting a regulator to a cylinder valve, the valveoutlet shall be wiped clean with a clean cloth free of oiland lint, and the valve shall be opened momentarily andclosed immediately.

The valve shall be cracked while standing to one side ofthe outlet, never in front of it. Fuel gas cylinder valvesshall not be cracked near other welding work or nearsparks, ?ame, or other possible sources of ignition.10.8.4.4Special Procedure for OxygenCylinders.The following shall be done after theregulator is attached to oxygen cylinders:

(1)Engage the adjusting screw and open the down-stream line to drain the regulator of gas.

(2)Disengage the adjusting screw and open the cylin-der valve slightly so that the regulator cylinder-pressuregauge pointer moves up slowly before opening the valveall the way.

(3)Stand to one side of the regulator and not in frontof the gauge faces when opening the cylinder valve.10.8.4.5Hammer or Wrench.A hammer orwrench shall not be used to open cylinder valves that are?tted with hand wheels.

10.8.4.6Special Wrench.Cylinders not having?xed hand wheels shall have keys, handles, ornonadjustable wrenches on valve stems while thesecylinders are in service so that the gas ?ow can be turnedoff quickly in case of emergency. In multiple cylinderinstallations, at least one such wrench shall always beavailable for immediate use.

10.8.4.7Valve Wide Open.When a high-pressure(nonlique?ed) gas cylinder is in use, the valve shall beopened fully in order to prevent leakage around the valvestem.

10.8.4.8Valve Partially Open.An acetylenecylinder valve shall not be opened more than approximatelyone and one-half turns and preferably no more than three-fourths of a turn, unless otherwise speci?ed by themanufacturer.

10.8.4.9Interference.Nothing shall be placed ontop of a cylinder when in use which may damage thesafety device or interfere with the quick closing of thevalve.

10.8.4.10Valves Closed.Cylinder valves shall beclosed whenever the equipment is unattended.

10.8.4.11Draining Regulator.Before a regulatoris removed from a cylinder, the cylinder valve shall beclosed and the gas released from the regulator.

10.8.4.12Secure Cylinders During Use.Asuitable cylinder truck, chain, or steadying device shall

E10.8.4.3This action, generally termed cracking,is intended to clear the valve of dust or dirt that otherwisemight enter the regulator.

E10.8.4.4If oxygen at high pressure is suddenlyapplied, it is possible to cause ignition of regulatorcomponents and injure the operator. See CGA PamphletE-4 for additional information.

E10.8.4.8This is so that it may be closed quickly incase of emergency.

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be used to keep cylinders from being knocked over whilein use.

10.8.4.13Fire Protection.Cylinders shall be keptfar enough away from actual welding or cuttingoperations so that sparks, hot slag, or ?ame will not reachthem, otherwise ?re resistant shields shall be provided.10.8.4.14Electric Circuits.Cylinders shall not beplaced where they might become part of an electricalcircuit. Contacts with third rails, trolley wires, etc. shallbe avoided. Cylinders shall be kept away from radiators,piping systems, layout tables, etc. that may be used forgrounding electric circuits such as for arc weldingmachines. The tapping of electrodes against a cylindershall be prohibited. Do not strike an arc on cylinders.10.8.4.15Fuel Gas Cylinder Withdrawal Rates.Withdrawal rates from gas cylinders shall not exceedmanufacturers’ recommendations.

E10.8.4.14Cylinders should not be so grounded, orlocated, where they can become part of an electric circuit.Arc damaged cylinders may leak or explode.

E10.8.4.15In the case of acetylene, excessivewithdrawal rates can lead to acetone depletion from thecylinder. Some materials may be damaged by acetoneand create leaks. The stability of acetylene may bereduced. In the case of lique?ed fuel gases, excessivewithdrawal rates will cause refrigeration.

E10.8.5.1Leaks can lead to oxygen de?cient orexplosive atmospheres.

E10.8.5.2Outdoors, the cylinder valve may beopened slightly to gradually discharge the contents.

10.8.5Cylinder Emergencies

10.8.5.1Fuel Valve Packing Leak.If a leak isfound around the valve stem of a fuel gas cylinder, thepacking nuts shall be tightened, or the cylinder valve closed.10.8.5.2Fuel Gas Leaks Which Cannot beStopped.If tightening the packing nut does not stop avalve stem leak, or if a fuel gas valve is leaking at the sealand cannot be stopped by closing the valve ?rmly, or if aleak should develop at a cylinder fuse plug or other safetydevice, then the fuel gas cylinders shall be moved to asafe location outdoors, away from any source of ignition,marked properly, and the supplier advised.

When a leaking cylinder cannot be moved safely to alocation outdoors, the area or building shall be immedi-ately evacuated and the ?re department noti?ed of theemergency.

A precautionary sign shall be posted not to approach theleaking cylinder with a lighted cigarette or source of ignition.

10.8.5.3Fuel Cylinder Fires.Small ?res at fuelgas cylinders, usually resulting from ignition of leaksdescribed in 10.8.5.1 and 10.8.5.2, shall be extinguished,if possible, by closing the cylinder valve or by the use ofwater, wet cloths, or ?re extinguisher. The leaks shallthen be treated as described in those sections.

In the case of a large ?re at a fuel gas cylinder, such asfrom the functioning of a fuse plug or safety device, per-sonnel shall be evacuated from the area, and the cylinderkept wet with a heavy water stream to keep it cool.

E10.8.5.3It is usually better to allow the ?re tocontinue to burn and consume the escaping gas,otherwise it may reignite with explosive violence. Ifcircumstances permit, it is often better to allow thecylinder ?re to burn out in place rather than attempt tomove the cylinder.

If the cylinder is located where the ?re should not beallowed to burn out in place, attempts may be made tomove it to a safer location, preferably outdoors.Personnel should remain as distant as possible, and thecylinder should be kept cool with a water stream.

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10.9Cylinder Manifolding

10.9.1Approval.Fuel gas manifolds and high-pressure oxygen manifolds for use with oxygen cylindershaving a DOT service pressure above 250 psig (1724kPa) shall be approved either separately for eachcomponent part or as an assembled unit.

10.9.2Gas Service.All manifolds and parts shall beused only for the gases for which they are approved.10.9.3Fuel Gas Manifold Capacity Limits andLocations.Fuel gas manifold capacity limits andlocations shall be in accordance with NFPA 51.

E10.9.3NFPA 51 has established a 3000 cubic foot(84 cubic meters) total nonlique?ed gas capacity as anindoor limit for fuel gas cylinders connected to onemanifold. The rationale for this limit is that a typicalbuilding of 100 feet by 100 feet with a 15 feet ceiling(150000 cubic feet, 4200 cubic meters) could contain aleak of 3000 cubic feet of acetylene and not exceed thelower explosive limit if uniformly distributed. Acetylenehas the lowest explosive limit of the commonly used fuelgases. See NFPA 51 for additional details.

10.9.4Oxygen Manifold Capacity Limits andLocations.Oxygen manifold capacity limits andlocations shall be in accordance with NFPA 51.10.9.5Manifold Requirements.Fuel gas andoxygen manifolds requirements shall be in accordancewith NFPA 51.

10.9.6Manifold Installation and Operation.Manifold installation and operation shall be inaccordance with NFPA 51.

11.Arc Welding and Cutting

Equipment Safety

11.1General

11.1.1Scope.This section contains safetyprecautions speci?c to the installation and operation ofarc welding and cutting equipment.

11.1.2Equipment.Arc welding and cuttingequipment shall be chosen as speci?ed in 11.2 and shallbe installed as speci?ed in 11.3.

11.1.3Personnel.Persons in charge of the equipmentor designated to operate the arc welding and cuttingequipment shall have been properly instructed andquali?ed to maintain or operate such equipment andapproved as competent for their work responsibilities.Rules and instructions covering the operation andmaintenance of the arc welding and cutting equipmentshall be readily available.

E11.1.2Gas equipment used in arc welding should behandled as described in Clause 10, Oxyfuel Gas Weldingand Cutting Safety. See 11.5.5.

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11.2Safety Aspects in Selection of Arc WeldingEquipment

11.2.1Safety Standards.Safety in design of arcwelding equipment shall be in compliance withapplicable NEMA and ANSI standards. Special purposemachines not covered by the above listed standards shallconform in all aspects to the standards set forth in thispublication.

11.2.2Environmental Conditions.When usingalternating current (ac) or direct current (dc) arc weldingmachines, the welding operator shall take special care toprevent electrical shock, when working under electricallyhazardous conditions. The manufacturer shall be consultedwhen unusual service conditions are encountered.

E11.2.2Water or perspiration may cause electricallyhazardous conditions. Electrical shock may be preventedby the use of nonconductive gloves, clothing, and shoesand avoiding contact with live electrical parts.

Other examples of electrically hazardous conditions arelocations in which the freedom of movement is restrictedso that the operator is forced to perform the work in acramped (kneeling, sitting, lying) position with physicalcontact with conductive parts, and locations that are fullyor partially limited by conductive elements and in whichthere is a high risk of unavoidable or accidental contactby the operator. These hazards can be minimized by insu-lating conductive parts near the vicinity of the operator.If a signi?cant amount of work time is spent in electricallyhazardous conditions, the use of automatic controls is rec-ommended to reduce the no-load voltage to a value not toexceed 38 volts rms ac or 50 volts direct current (dc) at ratedinput voltage. This also applies to 11.2.3.1. Examples ofunusual service conditions are described in ANSI/NEMAEW1, Electric Arc Welding Power Sources.

11.2.3Other Conditions

11.2.3.1Open-Circuit Voltage (SpecialProcesses).When special welding and cutting processesrequire open-circuit voltages higher than those speci?edin ANSI/NEMA EW1, adequate insulation or othermeans shall be provided to protect the operator frommaking contact with the high voltage.

11.2.3.2Work Terminal to Grounded Enclosure.The work shall be grounded in accordance with 11.3.2. Inthe case of installations that have followed the practice ofgrounding the work lead at a power source terminal, thatitself is grounded by a connection to the grounded powersource enclosure, the power source terminal shall beconnected to the grounded power source enclosure by aconductor smaller in diameter (at least two wire gageshigher) than the power source enclosure groundingconductor, and the terminal shall be marked to indicate thatit is grounded. In no case shall a connection between thework lead terminal and the grounded power sourceenclosure be intentionally used instead of the work lead tocarry welding current.

E11.2.3.1Some processes such as plasma arccutting may utilize open-circuit voltages as high as 400 volts dc. Precautionary labeling, workplace placards,or special employee training should be considered whenhigh open-circuit voltage is present. See 11.2.2.E11.2.3.2The practice of connecting the workterminal to the power source enclosure is notrecommended and should be avoided. It is likely for awelding operator to inadvertently remove the connectionbetween the work clamp and the work piece and therebycause welding current to ?ow through the groundingconductors of the electrical system. Measures must betaken to prevent the ?ow of welding current throughgrounding conductors. Grounding conductors are sizedfor other purposes. Welding currents may be too high forsome grounding conductors in the welding area or thepower network.

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11.2.3.3Welding Terminals.Terminals forwelding leads shall be protected from accidentalelectrical contact by personnel or by metal objects, forexample, vehicles, crane hooks.

E11.2.3.3Protection may be obtained by the use ofdead front construction utilizing receptacles for plugconnections, by locating terminals in a recessed openingor under a nonremovable hinged cover, by heavyinsulating sleeves or by other equivalent mechanicalmeans to satisfy the requirements.

E.11.2.3.4See NFPA 79.

11.2.3.4Portable Control Devices.Noconnections for portable control devices, such as pushbuttons, to be carried by the operator shall be connectedto an ac circuit of higher than 120 volts. Exposed metalparts of portable control devices operating on circuitsabove 50 volts shall be grounded by a groundingconductor in the control cable.

11.2.3.5Autotransformers.Autotransformers orac reactors shall not be used to draw welding currentdirectly from any primary ac power source having avoltage exceeding 80 volts.

11.2.3.6Equipment Loading.Care shall be takenin applying arc welding equipment to ensure that theampere rating chosen is adequate to handle the job.Welding machines shall not be operated above the ampereratings and corresponding rated duty cycles as speci?edby the manufacturer and shall not be used for applicationsother than those speci?ed by the manufacturer.

E11.2.3.6Using welding machines beyond ampereor duty cycle ratings causes overheating which results inpremature deterioration of insulation and increases theelectrical shock hazard. Consideration should be given tothe fact that actual welding currents may be higher thanshown by indicators on the machines if welding is donewith short leads or low arc voltages. Particularly highover-currents are likely on general purpose weldingmachines when used with low arc voltage processes suchas gas tungsten arc welding.

E11.2.3.7See also 11.2.3.6. Refer to 11.5.4 foradditional information.

11.2.3.7Welding Cables.Welding cables shall beof the ?exible type designed especially for the rigors ofwelding service and of a size adequate for reasonablyexpected current and duty cycles. Special attention shall be paid to the insulation of cables used withequipment which includes high-voltage, high-frequencyoscillators.

11.3Installation of Arc Welding Equipment11.3.1Code Requirements.Installation includinggrounding, necessary disconnects, fuses, and type ofincoming power lines shall be in accordance with therequirements of the current NFPA 70, National ElectricalCode?, and all local codes.

11.3.2The Work.The workpiece or metal uponwhich the welder welds shall be grounded independent ofthe welding leads to a good electrical ground unless aquali?ed person assures it is safe to work on anungrounded workpiece.

E11.3.2When the work terminal is grounded, careshould be taken to see that the workpiece is not separatelygrounded. Refer to 11.3.2.1. Before welding is attemptedthe operator should check to be sure that the worklead isproperly connected. This will eliminate the chance ofwelding current being misdirected into the groundingconductor system of other equipment. Misdirectedwelding current can damage conductors which do nothave adequate ampacity. See Article 630.15 of NFPA 70,National Electrical Code?.

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11.3.2.1Grounding.Grounding shall be done bylocating the work on a grounded metal ?oor or platen, orby connection to a grounded building frame or othersatisfactory ground. Care shall be taken to avoid the ?owof welding current through a connection intended onlyfor safety grounding since the welding current may be ofa higher magnitude than the grounding conductor cansafely carry.

E11.3.2.1The work lead and work lead clamp aresometimes incorrectly referred to as “ground lead” and“ground clamp.” The work lead and the ground lead arenot the same. The work lead should not be referred to asthe grounding lead. It is preferable to connect the worklead directly to the work. Hence, it is inappropriate torefer to the lead as “ground lead” or the connection as“ground clamp.” The work clamp should never be storedby clamping it to any part of the grounded power sourceframe. Grounding of electrical systems and circuitconductors is done to limit voltages due to lightning, linevoltage surges, or unintentional contact with highervoltage lines, and to stabilize voltage to ground duringnormal operations.

It also facilitates over-current device operation in case ofground faults. (See Article 250.4 of NFPA 70, NationalElectrical Code?.) Grounding of workpieces, equipmenthousings, metal cabinets and frames, or other conductivematerial that form part of the equipment is done to limitthe voltage to ground on these items. Limiting the voltageby grounding helps to prevent accidental shocks whenequipment is misconnected or insulation fails. (SeeArticle 250.4 of NFPA 70, National Electrical Code?.)Equipment used with ungrounded supply systems, suchas is used in naval shipboard systems, should be con-nected in accordance with the requirements of the author-ity having jurisdiction.

Special radio frequency grounding may be advisable forequipment using high-frequency arc stabilizers. (SeeRecommended Installation and Test Procedures for HighFrequency Stabilized Arc Welders, 1970, Arc WeldingSection of NEMA.)

11.3.2.2Work Lead.Welding current shall bereturned to the welding machine by cable with suf?cientcurrent capacity. However, connection of a cable fromthe welding machine to a common conductor or properlybonded structure on which the work rests, or to which thework is connected, shall be a permissible alternateprocedure. Single-phase alternating current machines ingroups of three with their inputs connected in delta to athree-phase supply circuit connected in wye on thesecondary circuits shall be permitted to use a single worklead from the neutral of the three units to the structurebeing welded.

The work lead shall use a single cable of a size suitablefor the current rating of at least one machine.

11.3.3Conduit and Pipe Ground Limitations.Conduits containing electrical conductors shall not beused for completing a work lead circuit. Pipelines shallnot be used as a permanent part of a welding circuit, butmay be used during construction, extension, or repairproviding the current is not carried through threaded

E11.3.2.2Refer to 11.3.6 for voltage and shockconsideration. With the permissible alternate procedure,care should be taken that no other electrical connection orpath exists.

E11.3.3Current which passes through joints which arenot intended for such use can cause hot spots to develop.These hot spots can lead to the development of hidden?res or explosions. For other precautions, see 11.4.

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joints, ?anged bolted joints, or caulked joints. In addition,special precautions shall be used to avoid sparking at theconnection of the work lead cable.

11.3.4Prohibited Work Lead Connection.Chains,wire ropes, cranes, hoists, and elevators shall not be usedto carry welding current.

11.3.5Electrical Continuity in Structures.Whenduring construction or modi?cation, a building or anyother fabricated metal structure is used for a weldingcurrent return circuit, it shall be checked to ascertainwhether proper electrical contact exists at all joints.Sparking or heating at any point shall be cause forrejection of the structure as a return circuit.

11.3.6Connections to Minimize Shock Hazard.Where welders are working on one structure, suf?cientlyclose to each other, and someone is likely to touch theexposed parts of more than one electrode holdersimultaneously, machines shall be connected to minimizeshock hazard as follows:

11.3.6.1DC Machines.Unless required by specialcases, all dc machines shall be connected with the samepolarity.

11.3.6.2AC Machines.Unless required by specialcases, all single-phase ac machines shall be connected tothe same phase of the supply circuit and with the sameinstantaneous polarity.

11.3.6.3Special Cases.The operator and otherarea personnel shall be instructed on of the importance ofavoiding simultaneous contact of the exposed parts ofmore than one electrode holder.

E11.3.6.1A test lamp or voltmeter may be used todetermine whether the connections are correct. See11.3.6.3

E11.3.6.2A voltmeter can be used to determinewhether the connections are correct. See 11.3.6.3.E11.3.4See 11.4.9.2.

E11.3.5Approval should be obtained from the owneror responsible person before proceeding.

E11.3.6.3When operations on one structureinvolve several welding machines, the dc weldingprocess requirements may require the use of bothpolarities, or supply circuit limitations for ac weldingmay require distribution of machines among the phasesof the supply circuit. No-load voltages between electrodeholders will be two times normal in dc or 1, 1.41, 1.73, ortwo times normal on ac machines. Similar voltagedifferences will exist if both ac and dc welding are doneon the same structure.

E11.4This section applies to all arc welding and cuttingprocesses. For gas shielded arc welding, see alsorecommended practice documents such as AWS C5.6-89,Recommended Practices for Gas-Metal Arc Welding.E11.4.1Those sections of particular interest areClause 4, Protection of Personnel and the General Area;Clause 5, Ventilation; and Clause 6, Fire Prevention andProtection.

E11.4.2Clean and tight connections are necessary toprevent local heating. Properly insulated and dryconnections are necessary to prevent stray electricalcurrents and possible shock or short circuits.

Coiled welding cable should be kept to a minimum and any excess is to be spread out before use to avoid

11.4Operation

11.4.1Worker Instruction.Workers assigned tooperate or maintain arc welding equipment shall beacquainted with those parts of this standard applicable totheir work assignments.

11.4.2Checking Connections.After assembling anyconnection to the machine, each assembled connectionshall be checked before starting operations to ascertainthat it is properly made. In addition, the work lead shallbe ?rmly attached to the work; magnetic work clampsshall be freed from adherent metal particles and spatter oncontact surfaces.

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overheating and damage to insulation. Jobs alternatelyrequiring long and short cables should be equipped withinsulated connectors so that idle lengths can be discon-nected when not needed.

11.4.3Machine Frame Grounding.Grounding ofthe welding machine frame shall be checked. Specialattention shall be given to safety grounding connectionsof portable machines. See NFPA 70, National ElectricCode?, Article 250, Grounding.

11.4.4Leaks.There shall be no leaks of coolingwater, shielding gas, or engine fuel that can adverselyaffect the welder’s safety.

11.4.5Safe Operating Instructions.Written rulesand instructions covering the safe operation of equipmentshall be made available to the welder and shall be strictlyfollowed.

11.4.6Work Interruptions.When the welder leavesthe work or stops for an appreciable time, the equipmentor machine output shall be turned off or de-energized.11.4.7Moving the Machine.When the machine is tobe moved, the input power supply to the equipment shallbe electrically disconnected.

11.4.8Equipment Not in Use.When not in use,metal and carbon electrodes shall be removed fromholders to eliminate danger of electrical contact withpersons or conducting objects. When not in use, electrodeholders shall be so placed that they cannot make electricalcontact with persons, conducting objects, such as metalor wet earth, ?ammable liquids, or compressed gascylinders. When not in use, guns of semiautomaticwelding machines shall be placed so that the gun switchcannot be operated accidentally.

11.4.9Electric Shock.The welder shall be trained toavoid shock. Unexplained shocks shall be reported to thesupervisor for investigation and correction prior tocontinuing. Safe procedures shall be observed at all timeswhen working with equipment having voltages necessaryfor arc welding.

11.4.9.1Live Metal Parts.The welder shall neverpermit the live metal parts of an electrode, holder, orother equipment, to touch bare skin or any wet coveringof the body.

11.4.9.2Insulation.Welders shall protectthemselves from electrical contact with the work orground by dry insulating material; particularly, they shallbe protected against large area contacts by insulationwhen working in a sitting or prone position.

E11.4.9.2When the worker is required to be on aladder while welding or cutting, the ladder should benonconductive or otherwise insulated from work andground. Dry shoes in good condition should be worn.Rubber soled shoes or boots should be worn in dampareas. Workers should wear protective boots whenworking in standing water or other wet areas.

E11.4.9Conductive articles of jewelry and clothing(such as watch bands, bracelets, rings, key chains,necklaces, metalized aprons, cloth with conductivethread, or metal headgear) should not be worn if theymight contact exposed energized parts. However, sucharticles may be worn if they are rendered nonconductiveby covering, wrapping, or other insulating means.E11.4.4Moisture can carry electric current and increasethe chance of electric shock, shielding gases can causeasphyxiation, and fuels can cause explosions or ?res.

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To reduce the possibility of welding current arcingthrough the suspension wire rope when performing weld-ing from suspended scaffolds, use an insulated thimble toattach each suspension wire rope to its hanging support(such as cornice hook or outrigger). Insulate excess sus-pension wire rope and insulate any additional indepen-dent lines from grounding. Cover the suspension wirerope with insulating material extending at least 4 feetabove the hoist. Insulate the tail line below the hoist toprevent contact with the platform. Guide or retain theportion of the tail line that hangs free below the scaffoldso that it does not become grounded (see 29 CFR1926.451(f)(17)).

11.4.9.3Gloves.Dry gloves in good conditionshall be used.

E11.4.9.3Use of damp or wet gloves may lead toelectric shock. Where moisture or perspiration is aproblem, rubberized gloves or other insulating meansshould be used. See also 4.3.2 and E11.2.2.

11.4.9.4Holders and Guns.Electrode holdersand guns shall be well insulated and kept in good repair.11.4.9.5Water Immersion.Electrode holdersand guns shall not be cooled by immersion in water.11.4.9.6Water-Cooled Holders.Water-cooledholders and guns shall not be used if any water leak orcondensation exists which would adversely affect thewelder’s safety.

11.4.9.7Changing Electrodes.Except forshielded metal arc welding, the output of the weldingmachine shall be electrically de-energized whenelectrodes or contact tips are changed.

11.4.9.8Other Practices to Avoid.The weldershall not coil or loop welding electrode cable around partsof the body. Precautions shall be taken to prevent shock-induced falls when the welder is working above groundlevel.

11.4.9.9Wearers of Pacemakers.Wearers ofpacemakers or other electronic equipment vital to lifeshall check with the life support manufacturers and theirclinician to determine whether a hazard exists.11.5Maintenance

11.5.1General.All arc welding equipment shall bemaintained in safe working order at all times. The welder ormaintenance personnel shall report any equipment defect orsafety hazard to the supervisor, and the use of suchequipment shall be discontinued until its safety has beenassured. Repairs shall be made by quali?ed personnel only.11.5.2Welding Equipment.Welding equipmentshall be maintained in good mechanical and electricalcondition to avoid unnecessary hazards. On rotatingelectrical equipment, commutators shall be kept clean toprevent excessive ?ashing.

E11.5.1Periodic inspections are stronglyrecommended.

E11.4.9.9Welders and other persons who mustwork in a welding environment should inform their doctorsprior to undergoing device installation procedures.

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11.5.2.1Inspection.Welding equipment shall beinspected frequently to detect accumulations of foreignmatter that would interfere with ventilation or insulation.Electrical coil ventilation ducts shall be similarlyinspected and cleaned. Fuel systems on engine-drivenmachines shall be inspected and checked for possibleleaks and accumulations of water that might causerusting. Rotating and moving components shall be keptproperly shielded and lubricated.

11.5.2.2Welding in the Open.Weldingequipment used in the open shall be protected frominclement weather conditions. Protective covers shall notobstruct the ventilation necessary to prevent overheatingof the machine.

E11.5.2.1Dirt on electrical equipment can increasetemperature, decrease service life, and possibly lead toshort circuiting.

It is good practice to blow out the entire welding machinewith clean dry compressed air using adequate safety precautions.

E11.5.2.2Air ?lters in the ventilating system of theelectrical components should not be used unless providedby, or approved by, the manufacturer of the weldingmachine. The reduction of air ?ow resulting from the useof an air ?lter on equipment not so designated can subjectinternal components to an overheating condition andsubsequent failure.

E11.5.2.3Modi?cations should only be performedby the equipment manufacturer or a quali?ed servicetechnician.

11.5.2.3Modi?cations.When it is necessary tomodify equipment, such as in order to meet noise levelrequirements, it shall be determined that themodi?cations or additions to the equipment do not causethe electrical or mechanical ratings to the equipment to beexceeded or overloaded.

11.5.3Wet Machines.Machines which have becomewet shall be thoroughly dried and properly tested beforebeing used. When not in use, the equipment shall beadequately protected or stored in a clean, dry place.11.5.4Welding Cable.Welding cable shall beinspected for wear or damage. Cables with damagedinsulation or connectors shall be replaced or repaired toachieve the mechanical strength, insulating quality,electrical conductivity, and water tightness of the originalcable. Joining lengths of cables shall be done by methodsspeci?cally intended for the purpose. The connectionmethods shall have insulation adequate for service.11.5.5Compressed Gases.Use of compressed gasesfor shielding in arc welding operations shall follow theapplicable provisions of Clause 10, Oxyfuel Gas Weldingand Cutting Safety.

E11.5.4Disconnected welding cable leads should beproperly stored to prevent inadvertent completion ofelectrical circuits.

12.Resistance Welding Safety

12.1General

12.1.1Scope.The scope of this section is limited towelding equipment using resistance welding principles as de?ned in the AWS publication entitled AWSA3.0M/A3.0, Standard Welding Terms and De?nitions.Users are further referred to Part I herein which isapplicable to general safety in welding and cutting.12.1.2Selection.All resistance welding equipmentshall be selected for safe application to the work

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