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WTIA Technical Note No. 7
Health and Safetyin Welding
The WTIA National Diffusion Networks Project is supported byFederal and State Governments and Australian industry
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CRC-WSCRC-WS
Welding Technology Institute of AustraliaThe Welding Technology Institute of Australia (WTIA) is the recognised national Australian Bodyrepresenting the overall interests of the “welding” industry, with its primary goal to: “assist inmaking Australian Industry locally and globally competitive in welding-related activities”. The Goaland Strategies within its Business Plan cover the ‘Total Life Cycle of Welded Products/Structures’.
The WTIA is a membership based, cooperative, not-for-profit, national organisation representing
the Australian welding industry and is registered as a ‘Company Limited by Guarantee” underthe Australian Corporations Law. WTIA is governed by a Council elected by the Divisions andCorporate Members.
Formed in 1989 through an amalgamation of the Australian Welding Institute (AWI) (founded1929) and the Australian Welding Research Association (AWRA) (founded 1964), its key roleshave been, and still are, predominantly in technology transfer, certification of personnel, educationand training, provision of technical services and facilitating research and development.
Through its Council, Boards and Industry Support Groups, and Technical Panels it hasrepresentation from a tremendous range of industry, government authorities and educationalinstitutions both locally and internationally.
Membership is offered within various categories and professional levels, presently consistingof approximately 1,400 individual members and 300 company members, whose annualsubscriptions provide a significant portion of the operating costs of the organisation.
The current staff of 22 includes 13 engineer/technologists with a variety of specialist backgroundsin welding technology. This expertise is complemented by Industry Support (SMART andTechnology Expert) Groups and Technical Panels with over 300 technical specialists, and
by a number of WTIA voluntary Divisional Bodies in all States and Territories. Together theycontribute on a significant scale to Australian Industry through its excellent network of volunteersthroughout Australia and the wide cross-section of its membership from MD to welder.
The WTIA provides a very wide range of services to industry across Australia, Governmentand individual members. It is the body representing Australia on the International Institute ofWelding, is a Core Partner of the CRC for Welded Structures, and it has a number of MOUswith kindred local and overseas bodies. It is actively involved in numerous initiatives to assistin improving the competitiveness of Australian Industry.
WTIA National Diffusion Networks Project, SMARTTechNet Project and OzWeld Technology SupportCentres Network Welding technology in the broadest sense plays a major role in Australia’s well-being and isutilised by over 20,000 Australian businesses large and small with over 300,000 employees.The Welding Technology Institute of Australia (WTIA) is a significant player with industry inpromoting improvements in industry through optimum use of Technology.
The Federal Industry Minister, Ian Macfarlane, announced that the WTIA has received a $2.45mgrant from the AusIndustry Innovation Access Program (IAccP) – Industry. The Institute launchedits new Industry Sectoral Projects (ISPs) from 1 September 2003 as par t of the WTIA NationalDiffusion Networks Project. The Projects involve the implementation of a structured weldingand joining technology demonstration and improvement program in seven Australian industrysectors over three years (2003-2006).
The sectoral strategy involves the WTIA working directly with leading Australian firms, SMEs,supply chains and technology specialists in the OzWeld Technology Support Centres (TSCs)Network to help them:• analyse and define the key challenges, opportunities and requirements that will govern the
competitiveness of Australia’s capability in each sector and identify specific areas wherewelding, joining and fabrication innovation and technology needs to be upgraded andtransferred to improve both their own and Australia’s competitive advantage and marketperformance in that sector;
• demonstrate project activities and identify how the solutions can be implemented, documentthe activities of the demonstration projects and outcomes, disseminate activities to the widerindustry and plan activities for future actions needed, including research, development,education, training, qualification and certification.
• document key Expert Technology Tools and Technical Guidance Notes for each technology/ sector application and facilitate the ongoing uptake, tailored application and skillsdevelopment in each of the welding/joining/fabrication technologies identified through theprogram.
The new industry sectors to be tackled include rail, road transport, water, pressureequipment, building & construction, mining and defence.
The new NDNP will also act as an umbrella encompassing the two other projects for which wepreviously received substantial Federal Government, State Government and industry funding.
The OzWeld Technology Support Centres Network will continue to support solutions to meetthe needs of industry and will be expanded to 35 local and 20 overseas TSCs, all contributingappropriate and leading-edge technologies to assist all industry sectors.
The SMART TechNet Project, with its SMART Industry Groups and Industry Specific Groups(ISGs) already running in the Power Generation, Petro/Chemical, Pipelines, Alumina Processing,Inspection & Testing and Fabrication industr ies will continue in parallel with the new Project, withpotential for interesting “cross pollination” with groups for the new Industry Sectoral Projects
(ISPs) and SMART Groups.Major benefits from this Project are overall improvement and competitiveness of Australianindustry through the use of latest proven technology, economically diffused by a greatly improvednetwork, as well as improved and expanded services to sponsor companies. The Project isbelieved to be the major practical strategy for rapid improvement of our “welding” businesses.The returns on investment for all parties on the WTIA OzWeld Technology Support CentresProject and SMART TechNet Project have been enormous. The return on this new NationalDiffusion Networks Project is expected to be even higher for par ties involved.
Published by the Welding Technology
Institute of Australia
Editors:
Mr Ben Gross
WTIA Research and Technology Manager
Prof Ian Henderson
WTIA Manager Technical Panels
Ms Anne Rorke
WTIA Technology Transfer Coordinator
Mr Bushan Salunke
WTIA Expert Technology Tool Coordinator
WTIA
ABN 69 003 696 526
Unit 3, Suite 2 9 Parramatta Road
Lidcombe NSW 2141
PO Box 6165
Silverwater NSW 1811
Tel: +61 (0)2 9748 4443
Fax: +61 (0)2 9748 2858
Email: [email protected]
Website: www.wtia.com.au
Executive Director – Mr Chris Smallbone
President – Mr Pat Kenna
Honorary Secretaries
New South Wales & ACT: Jeanette Cryer,
PO Box 1175, Menai, NSW 2234
Tel: (02) 9543 2452;
Queensland: Susan Bowes,PO Box 744, Archerfield Qld 4108
Tel: (07) 3711 6554;
Western Australia: Mary Forward,
PO Box 123, Kelmscott, WA 6991
Tel: (08) 9496 0926;
South Australia & NT: Pat Johnstone,
PO Box 133, Hove SA 5048 Tel: (08) 8377 3181;
Victoria & Tasmania: Brian Hamilton, PO Box
204, Mooroolbark Vic 3128 Tel: (03) 9726 0500.
WTIA Technology Managers
New South Wales & ACT:
Paul Grace; Tel: (02) 9748 4443;
Regional New South Wales:
Glen Allan Tel: (02) 4935 5445;
Queensland:
Leon Rosenbrock Tel: (07) 3364 0770;
Northern Territory:
Freecall: 1800 620 820;
Western Australia:
Ian Henderson Tel: (08) 9368 4104;
Regional Western Australia:
Geoff Hall Tel: (08) 9599 8614;
South Australia:
Greg Terrell Tel: (08) 8303 9175;
Victoria & Tasmania:
Alan Bishop Tel: (03) 9214 5052.
Core Partner of the Cooperative
Research Centre for Welded
Structures
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for the Welding Industry
What are they?An Expert Technology Tool (ETT) is a medium for diffusion andtake-up of technological information based on global researchand development (R&D) and experience to improve industryperformance.
It can be formatted as a hard copy, software (fixed, interactiveor modifiable), audiovisual (videos and sound tapes) or physicalsamples. It can be complemented by face-to-face interaction,on-site and remote assistance, training modules and auditingprograms.
The diagram overleaf and the information below show howthe WTIA has introduced a group of ETTs to help companiesimprove their performance.
ETTs and the SME – how can they help my Total
Welding Management System?
A Total Welding Management System (TWMS) is a major ETTwith supporting ETTs created specifically to assist Australianindustry, particularly those Small to Medium Enterprises (SMEs)that do not have the time or finance to develop an in-housesystem. These companies, however, are still bound by legal
requirements for compliance in many areas such as OHS&R,either due to government regulation or to contract requirements.The TWMS developed by the WTIA can be tailor-made by SMEsto suit any size and scope of operation, and implemented in fullor in part as required.
What is Total Welding Management?
Total Welding Management comprises all of the elements shownin the left-hand column of the table shown overleaf. Each ofthese elements needs to be addressed within any company,large or small, undertaking welding, which wishes to operateefficiently and be competitive in the Australian and overseasmarkets.
The Total Welding Management System Manual (itself an ExpertTechnology Tool) created by the WTIA with the assistance ofindustry and organisations represented within a TechnologyExpert Group, overviews each of these elements in the left-hand column. It details how each element relates to effectivewelding management, refers to supporting welding-related ETTs,or, where the subject matter is out of the range of expertise of theauthors, refers the user to external sources such as accountingor legal expertise.
Knowledge Resource Bank The other columns on the diagram overleaf list the KnowledgeResource Bank and show examples of supporting ETTs whichmay, or may not, be produced directly by the WTIA. The aim,
however, is to assist companies to access this knowledge andto recognise the role that knowledge plays in a Total WeldingManagement System. These supporting ETTs may take anyform, such as a Management System e.g. Occupational Health,Safety and Rehabilitation (OHS&R), a publication e.g. WTIATechnical Note, a video or a Standard through to software, aone-page guidance note or welding procedure.
Clearly, ETTs such as WTIA Technical Notes, various Standards,software, videos etc are readily available to industry.
The group of ETTs shown overleaf relate to a general weldingfabricator/contractor. The ETT group can be tailor-made to suitany specific company or industry sector.
A company-specific Knowledge Resource Bank can be made bythe company omitting or replacing any other ETT or Standard.
Total Welding Management for Industry Sectors
Total Welding Management Systems and the associatedKnowledge Resource Banks are being developed for specificindustry sectors, tailored to address the particular issues ofthat industry and to facilitate access to relevant resources. Acompany-specific Total Welding Management System can bemade by the company adding, omitting or replacing any elementshown in the left hand column, or ETT or Standard shown inthe other columns. This approach links in with industry needsalready identified by existing WTIA SMART Industry Groupsin the Pipeline, Petrochemical and Power Generation sectors.Members of these groups have already highlighted the commonproblem of industry knowledge loss through downsizing,outsourcing and privatisation and are looking for ways to addressthis problem.
The concept of industry-specific Total Welding ManagementSystems and Knowledge Resource Banks will be extendedbased on the results of industry needs analyses being currentlyconducted. The resources within the Bank will be expandedwith the help of Technology Expert Groups including WTIATechnical Panels. Information needs will be identified for thespecific industry sectors, existing resources located either withinAustralia or overseas if otherwise unavailable, and if necessary,new resources will be created to satisfy these needs.
How to Access ETTs
Management System ETTs, whether they are the Total WeldingManagement Manual (which includes the Quality Manual),
OHS&R Managers Handbook, Procedures, Work Instructions,Forms and Records or Environmental Improvement System,can be accessed and implemented in a variety of ways. Theycan be:
• Purchased as a publication for use by industry. They mayaugment existing manuals, targeting the welding operationof the company, or they may be implemented from scratchby competent personnel employed by the company;
• Accessed as course notes when attending a publicworkshop explaining the ETT;
• Accessed as course notes when attending an in-houseworkshop explaining the ETT;
• Purchased within a package which includes training andon-site implementation assistance from qualified WTIA
personnel;• Accessed during face-to-face consultation;
• Downloaded from the WTIA website www.wtia.com.au
ETTs created by the WTIA are listed on page 122 of thisTechnical Note. Call the WTIA Welding Hotline on
1800 620 820 for further information.
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ELEMENTS:
1. Introduction
2. References
3. Management System
4. Management Responsibilities
(incl. Risk Management)
5. Document Control
6. Production Planning
7. Contracts
8. Design
9. Purchasing (incl. Sub-Contracting)
10. Production and Service Operations
11. Identification and Traceability
12. Welding Coordination
13. Production Personnel
14. Production Equipment
15. Production Procedures
16. Welding Consumables
17. Heat Treatment
18. Inspection and Testing
19. Inspection, Measuring and Test Equipment
20. Non-Conforming Product
21. Corrective Action
22. Storage, Packing and Delivery
23. Company Records
24. Auditing
25. Human Resources
26. Facilities
27. Marketing
28. Finance
29. OHS&R
30. Environment
31. Information Technology
32. Innovation, Research and Development
33. Security
34. Legal
TOTAL WELDING MANAGEMENTSYSTEM MANUAL
ETT: MS01(Including Welding Quality
Management System)
TN19 Cost Effective Quality Management
AS/NZS ISO 9001AS/NZS ISO 3834
AS 4360
TN6 Control of Lamellar TearingTN8 Economic Design of WeldmentsTN10 Fracture MechanicsTN12 Minimising CorrosionTN13 Stainless Steels for Corrosive
EnvironmentsTN14 Design & Construction Steel Bins
AS 4100AS 1210BS 7910
TN1 Weldability of SteelsTN2 Successful Welding of AluminiumTN4 Hardfacing for the Control of WearTN5 Flame Cutting of SteelsTN9 Welding Rates in Arc WeldingTN11 Commentary on AS/NZS 1554TN15 Welding & Fabrication Q&T SteelsTN16 Welding Stainless SteelsTN17 Automation in Arc WeldingTN18 Welding of CastingsTN21 Submerged Arc WeldingVideos – Welding Parts A & B
PG02 Welding of Stainless SteelTN19 Cost Effective Quality Management
AS/NZS 1554
AS 1988
ISO 14731
TN1 The Weldability of SteelTN9 Welding Rates in Arc WeldingTN19 Cost Effective Quality Management
TN3 Care & Conditioning of Arc WeldingConsumables
AS 4458
PG01 Weld Defects AS 2812
TN20 Repair of Steel Pipelines AS 2885
TN19 Cost Effective Quality Management
TN7 Health & Safety in WeldingTN22 Welding Electrical SafetyFume Minimisation Guidelines
Video – Fume AssessmentTN23 Environmental Improvement
Guidelines for Welding
AS 4804AS 1674.2
AS/NZS 14001
MS02 OHS&R – Managers HandbookMS03 OHS&R – ProceduresMS04 OHS&R – Work Instructions
MS05 OHS&R – Forms & RecordsMS06 Environmental Improvement MS
ETTs: MANAGEMENT SYSTEMS ETTs: OTHER RESOURCES ETTs: STANDARDS
KNOWLEDGE RESOURCE BANKi.e. resources for the Total Welding Management System (Notes 1 and 2)
TOTAL WELDING MANAGEMENT SYSTEMsupported by KNOWLEDGE RESOURCE BANK
Note 1: Examples of ETTS listed are not all-embracing and other ETTs within the global informationsupply can be added. ETTs can be formatted in a range of media.
Note 2: Dates and titles for the ETTs listed can be obtained from WTIA or SAI.
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This Technical Note:
This Technical Note is an Expert Technology Tool developed as part of the very successful WTIA SMART TechNetProject, supported by industry and Federal, State and Territory Governments. It is designed to give practical guidanceand the latest information available from a wide range of research and experience related to safety and health in
welding and allied operations; is presented in a form which gives positive guidance on safe practice together with abrief explanation for such practices. It is intended to assist all engaged in welding and allied processes, ranging fromtrainee-welders to senior management in industry and Governments; it will provide occupational hygienists withinformation on welding processes; it has been prepared by WTIA under the direction of its Technical Panel 9 WeldingOccupational Health and Safety and Environment . Members of this panel are listed in Appendix E
The Technical Note is a revision of the Second Edition published in 1998.It will be subject to further revisions from time to time.
The main changes from the previous edition are:• Gas welding, cutting and gouging completely revised and expanded• Technical improvement (e.g. information on Voltage Reduction Devices)• Major update on referenced Standards• Addition of new references
© Copyright 2004
This work is copyright. Apart from any use permitted under the Copyright Act 1968, no part may be reproduced by
any process without written permission from the Welding Technology Institute of Australia, PO Box 6165, Silverwater,NSW, Australia 1811
National Library of Australia card number and ISBN 0-920761-09-8
Acknowledgments
WTIA wishes to acknowledge the contribution of its members, members of WTIA Technical Panels and Committees,WTIA SMART Industry Groups and all those in industry who have contributed in various ways to the developmentof this Expert Technology Tool.
Particular acknowledgment for valuable help and guidance is given to the members of the above Technical Panel with
special mention of Mr Chris Dupressoir from Sydney Water Corporation, Dr Bob Kenyon from WorkCover Authorityof NSW, Mr Bruce Cannon from BlueScope Steel, Mr Alistair Forbes from BOC, and Mr Stan Ambrose, Mr SasankaSinha and Mrs Krystyna Whittaker from WTIA.
The Publishers also acknowledge the important assistance given by the International Institute of Welding through itsmany informative documents.
Disclaimer
While every effort has been made and all reasonable care taken to ensure the accuracy of the material contained herein,the authors, editors and publishers of this publication shall not be held to be liable or responsible in any way whatsoever
and expressly disclaim any liability or responsibility for any loss or damage costs or expenses howsoever incurred byany person whether the purchaser of this work or otherwise including but without in any way limiting any loss or damagecosts or expenses incurred as a result of or in connection with the reliance whether whole or partial by any person asaforesaid upon any part of the contents of this Expert Technology Tool.
Should expert assistance be required, the services of a competent professional person should be sought.
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Contents Page
1 Introduction ............................................................................................... 1
2 Scope ......................................................................................................... 2
3 Principles of Safe Working ....................................................................... 3
3.1 Basic Objective .................................................................................. 3
3.2 Risk Assessment ................................................................................ 3
3.3 Safe Working Practices ...................................................................... 4
3.4 Responsibility for Health and Safety ................................................. 4
3.5 Occupational Health and Safety Policy ............................................. 4
3.6 Occupational Health and Safety Programme..................................... 4
3.7 Safe Working Pre-requisites .............................................................. 5
4 Electric Arc Welding, Cutting and Gouging ............................................. 7
4.1 Introduction ....................................................................................... 7
4.2 Basic Requirements of Electrical Equipment .................................... 7
4.3 Welding Power Sources ..................................................................... 8
4.3.1 Types of Welding Power Sources or Machines .......................8
4.3.2 Compliance .............................................................................. 8
4.3.3 Open Circuit Voltage ...............................................................9
4.3.4 High Frequency Equipment .................................................... 9
4.3.5 Service Conditions ..................................................................9
4.3.6 Machine Loading ..................................................................... 9
4.3.7 Installation, Operation and Maintenance ................................9
4.4 Wire Feeders .................................................................................... 10 4.5 Welding Leads ................................................................................. 10
4.5.1 General .................................................................................. 10
4.5.2 Lead Connections ..................................................................11
4.5.3 Work Lead ............................................................................. 11
4.6 Electrode Holders ............................................................................ 11
4.6.1 Type ....................................................................................... 11
4.6.2 Class ...................................................................................... 12
4.6.3 Gripping Action .....................................................................12
4.6.4 Lead, Anchorage and Connection ......................................... 12
4.6.5 Routine Inspection .................................................................12
4.6.6 Use ......................................................................................... 12
4.7 Welding Torches and Guns ..............................................................13
4.8 Shielding Gas Cylinders and Pressure Hose....................................13
4.9 Safe Installation, Maintenance and Use of Arc Welding, Arc Cutting and Arc Gouging Equipment ...................................13
4.9.1 Management .......................................................................... 13
4.9.2 Installation and Handling of Equipment Connected to Electrical Supply ............................................................... 13
4.9.3 Installation and Handling of Engine Driven Equipment ....... 13
4.9.4 Maintenance and Inspection by Maintenance Personnel ...... 13 4.9.5 Operation by Welders and Operators ....................................14
4.9.6 Safe Working Practices by Welders and Operators ............... 14
4.9.7 Further Information ............................................................... 14
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5 Gas Welding, Flame Cutting and Gouging ............................................. 15
5.1 Introduction ..................................................................................... 15
5.2 Gas Properties and Particular Hazards ............................................ 15
5.2.1 Gases Used ............................................................................ 15
5.2.2 Oxygen .................................................................................. 15
5.2.3 Fuel Gases ............................................................................. 17
5.2.4 Shielding Gases ..................................................................... 18
5.3 Gas Supply ....................................................................................... 18
5.3.1 General .................................................................................. 18
5.3.2 Bulk Gas Supply....................................................................18
5.3.3 Cylinder Types and General Care ......................................... 18
5.3.4 Cylinder Storage, Transport, Handling and Use ................... 19
5.3.4.1 Storage ..................................................................... 19
5.3.4.2 Transport ..................................................................19
5.3.4.3 Handling ...................................................................19
5.3.4.4 Cylinder Use ............................................................ 19
5.3.4.5 Connection to Regulators and Hoses .......................20
5.3.5 Piping and Manifolds ............................................................20
5.3.6 Portable and Mobile Cylinder Supply ................................... 20
5.3.6.1 Storage ..................................................................... 20
5.4 Equipment Specifications and Assembly ......................................... 21 5.4.1 General .................................................................................. 21
5.4.2 Pressure Regulators and Gauges ........................................... 21
5.4.3 Hoses and Fittings .................................................................21
5.4.3.1 Requirements ...........................................................21
5.4.3.2 Colour Coding .......................................................... 21
5.4.3.3 Location ...................................................................22
5.4.3.4 Fittings ..................................................................... 22
5.4.3.5 Length and Diameter ............................................... 22
5.4.4 Blowpipes and Mixers ...........................................................22
5.4.4.1 Requirements for Blowpipes .................................... 22
5.4.5 Tips, Nozzles and their Attachment Fittings .........................22
5.4.6 Safety Devices ....................................................................... 22
5.4.6.1 Requirements ...........................................................22
5.4.6.2 Non-return Valve ...................................................... 22
5.4.6.3 Flame Arrester ..........................................................23
5.4.6.4 Flashback Arrester ................................................... 23
5.4.7 Personal Protective Equipment (PPE) ................................... 23
5.4.8 Cylinder Trolleys ...................................................................23
5.4.9 System Assembly ..................................................................23 5.4.9.1 General Compatibility .............................................. 23
5.4.9.2 Fuel Gas ...................................................................23
5.4.9.3 Flow Capacity .......................................................... 23
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5.5 Setting Up Plant Safely....................................................................26
5.5.1 Safe Equipment .....................................................................26
5.5.2 Training ................................................................................. 26
5.5.3 Rules and Instructions ...........................................................26
5.5.4 System Operation ..................................................................26
5.5.5 Equipment Inspection and Maintenance ...............................26
5.5.5.1 Inspection .................................................................26
5.5.5.2 Maintenance .............................................................26
5.5.5.3 Detailed Inspection and Maintenance ......................26
5.5.6 Flame Cutting and Ancillary Equipment ...............................27
5.6 Emergencies and Incidents ..............................................................27
5.6.1 Backfires and Flashback ........................................................27
5.6.2 Gas Leaks .............................................................................. 27
5.6.3 Ignition of Oxygen Regulators, Hoses and other High Pressure Equipment .................................................. 27
5.6.4 Cylinders in Fires ..................................................................28
5.6.5 Acetylene Cylinder Overheating ........................................... 28
5.6.6 Oxygen Cylinder Explosions ................................................ 29
6 Plasma Arc Welding and Cutting ............................................................31
6.1 Introduction ..................................................................................... 31
6.2 Process Features .............................................................................. 31
6.3 Electric Shock .................................................................................. 32
6.4 Noise ................................................................................................ 32
6.5 Arc Radiation (Non-ionising) ..........................................................33
6.6 Noxious Gases ................................................................................. 33
6.6.1 Production of Gases ..............................................................33
6.6.2 Recommendations .................................................................33
6.7 Fume ................................................................................................33
6.8 Dusts ................................................................................................ 33
7 Resistance Welding ................................................................................. 35
7.1 Introduction ..................................................................................... 35
7.2 Manufacture and Installation of Resistance Welding Equipment .... 35 7.2.1 Electrical Safety ....................................................................35
7.2.2 Mechanical Safety ................................................................. 35
7.3 Location of Equipment ....................................................................36
7.4 Personal Protective Equipment ........................................................ 36
8 Special Welding Processes ......................................................................37
8.1 Aluminothermic Welding ................................................................37
8.1.1. Thermit Process .....................................................................37
8.1.2 Applications .......................................................................... 37
8.1.3 Precautions ............................................................................ 37
8.2 Laser Welding and Cutting ..............................................................38 8.3 Electron Beam Welding ...................................................................38
8.3.1 Process ................................................................................... 38
8.3.2 Precautions ............................................................................ 38
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8.4 Electroslag Welding and Consumable Guide Welding ................. 39
8.4.1 Process .............................................................................. 39
8.4.2 Precautions ........................................................................ 39
8.5 Explosive Welding ........................................................................ 40
8.6 Friction Welding ........................................................................... 40
9 Brazing and Soldering ............................................................................ 41
9.1 Brazing and Soldering Processes.................................................. 41
9.2 Brazing Hazards ........................................................................... 41
9.2.1. Fluxes ................................................................................ 41
9.2.2 Filler Metals ...................................................................... 42
9.2.3 Explosion and Fire ............................................................42
9.2.3.1 Possible Sources ................................................. 42
9.2.3.2 Flame and Gas Heating ....................................... 42
9.2.3.3 Brazing Atmospheres .......................................... 42
9.2.3.4 Nitrate and Nitrite Salt Baths ..............................42
9.3 Soldering Hazards ........................................................................ 42
9.3.1 Toxic Fume and Salts ........................................................ 42
9.3.2. Safety Precaution for Fluxes ............................................. 43
9.3.3. Toxic Fume from Solder ................................................... 43
9.3.4 Fire Hazard – Rosin Based (Safety) Fluxes ......................43
9.4 Electrical Hazards ......................................................................... 44
9.5 Eye Injuries ................................................................................... 44
9.6 Cleaning Hazards.......................................................................... 44
9.7 Burns to Body ............................................................................... 44
10 Metal Preparation Processes ...................................................................45
10.1 The Need for Metal Preparation ................................................... 45
10.2 Metal Cleaning Processes .............................................................45
10.2.1 Chemical ........................................................................... 45
10.2.2 Physical ............................................................................. 45
10.3 Precautions with Preparation Processes ....................................... 45
10.3.1 Chemical Treatments ........................................................ 45
10.3.1.1 Caustic Solution Cleaning .................................. 45
10.3.1.2 Acid Solution Cleaning ....................................... 45
10.3.1.3 Pickling and Passivation pastes .......................... 46
10.3.1.4 Degreasing Chemicals ........................................ 46
10.3.1.5 Solvent Paint Strippers and Removers ................ 46
10.3.2. Physical Treatments ..........................................................46
10.3.2.1 Abrasive Plate Descaling and Cleaning ..............46
10.3.2.2 Mechanical Edge Preparation .............................47
10.3.2.3 Grinding and Abrasive Disc Cutting ................... 47
10.3.2.4 Deslagging, Chipping, Chiselling and Peening ..................................................... 47
10.3.2.5 Flame Cleaning ................................................... 47
10.4 Coated Metals ............................................................................... 47
10.5 Contaminated Surfaces .................................................................47
10.6 Metal Preparation in Special Locations ........................................ 47
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11 Metal Spraying ........................................................................................ 49
11.1 Introduction .................................................................................. 49
11.1.1 Basic Compounds .............................................................49
11.1.2 Hazards to Health .............................................................49
11.2 Surface Preparation ......................................................................49
11.3 Gas Fire and Explosion ................................................................49
11.4 Dust Fire and Explosion ...............................................................49
11.4.1 Need for Precaution ..........................................................49
11.4.2 Flammable Metal Dusts .................................................... 49
11.4.3 Self-Burning Dust Mixtures ............................................. 50
11.4.4 Collection of Metal Dusts ................................................. 50
11.4.5 Prevention of Dust Fire and Explosion .............................51
11.5 Health of Operators ......................................................................51
11.6 Personal Protective Equipment ..................................................... 51
11.7 Metal Spaying Guns .....................................................................51
11.8 Spray Booths ................................................................................ 51
12 Heat Treatment Processes .......................................................................53
12.1 Type of Process ............................................................................. 53
12.2 Hazards ......................................................................................... 53
12.3 Burns .............................................................................................53
12.4 Flame Heating .............................................................................. 53
12.5 Electrical Heating ......................................................................... 53
13 Precautions with Various Materials ........................................................ 55
13.1 Introduction .................................................................................. 55
14 Electric Shock ......................................................................................... 59
14.1 Introduction .................................................................................. 59
14.2 Factors Affecting Severity of Electric Shock ...............................59
14.3 Electricity Supply to the Welding Machine and Ancillary Equipment ................................................................. 59
14.4 Risk of Shock and Choice of Welding Process ............................60
14.4.1 Resistance Welding ...........................................................60
14.4.2 Manual Metal Arc, Arc Air Gouging ................................60
14.4.3 Gas Tungsten Arc Welding (GTAW) ................................60
14.4.4 Gas Metal Arc Welding (GMAW) and Flux Cored Arc Welding (GCAW) ............................... 60
14.4.5 Submerged Arc and Electroslag Welding .........................60
14.4.6 Plasma Welding and Cutting ............................................. 61
14.5 Avoiding the Risk of Electrocution in Manual Welding ............... 61
14.5.1 Preventing Contact with the Electrode .............................61
14.5.2 Preventing Contact with the Work Piece ..........................61
14.5.3 Avoiding Contact through Damaged Equipment or Poor Work Practices ...................................................... 61
14.5.4 Limiting or Eliminating the OCV ..................................... 61
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14.6 Assessing the Risk of Electric Shock ........................................... 62
14.6.1 Normal Environment ........................................................ 62
14.6.2 Hazardous Environment ................................................... 62
14.6.3 Environment with a High Risk of Electrocution ..............63
14.7 Voltage Reduction Devices (VRDs) and In-line Switches ........... 64
14.8 Multiple Welding Machines .........................................................64
14.9 Rescue of Victims ......................................................................... 64
14.10 Additional Guidance ..................................................................... 64
15 Arc, Flame and Laser Radiation .............................................................65
15.1 Radiation (Non-Ionising) and its Effects ...................................... 65
15.1.1 Ultraviolet Radiation (UV) ............................................... 65
15.1.2 Visible Radiation ..............................................................65
15.1.3 Infra-red Radiation (IR) .................................................... 65
15.2 Personal Protection ....................................................................... 65
15.3 Protection of Other Personnel ...................................................... 65
16 Fire and Explosion Protection.................................................................67
16.1 Introduction .................................................................................. 67
16.2 Causes of Fire ............................................................................... 67
16.2.1 Sparks and Hot Metallic Particles..................................... 67
16.2.2 Electrode Stubs .................................................................67
16.2.3 Oxygen and Fuel Gases .................................................... 67
16.2.4 Hose Locations ................................................................. 67 16.2.5 Gas Cylinders ...................................................................68
16.2.6 Containers and Piping ....................................................... 68
16.2.7 Partitions and Walls ..........................................................68
16.2.8 Electrical Connections ...................................................... 68
16.2.9 Ignition Temperature ........................................................ 68
16.2.10 Dust Fires and Explosions ................................................ 68
16.3 Dust and Fires in Explosions ........................................................ 68
16.3.1 Hazardous Dusts ...............................................................68
16.3.2 Prevention of Dust Explosions or Fires ............................68
16.3.3 Ventilation Ducting ...........................................................69 16.3.4 Fighting Dust Fires ...........................................................69
16.4 Safe Location ................................................................................ 69
16.5 Fire Protection .............................................................................. 69
16.5.1 Fire Extinguishers .............................................................69
16.5.2 Fire Watchers .................................................................... 69
16.5.3 Fire Watch Duties ............................................................. 70
16.6 Responsibility for Fire Protection ................................................ 70
17 Fume and Ventilation .............................................................................. 71
17.1 Introduction .................................................................................. 71
17.2 Fume .............................................................................................71
17.3 Formation of Fume ....................................................................... 71
17.4 The Constituents of Welding Fume .............................................. 71
17.5 Welding Fume Concentrations ..................................................... 72
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17.6 Control of Fume .......................................................................... 72
17.7 Ventilation ................................................................................... 72
17.7.1 Necessity for Ventilation ................................................ 72
17.7.2 Selection of Ventilation Method ..................................... 72
17.7.3 Local Exhaust Ventilation .............................................. 72
17.7.4 Mechanical Dilution Ventilation ....................................73
17.7.5 Natural Ventilation .........................................................74
17.8 Ventilation for Particular Process ................................................ 74
17.8.1 Gas Welding, Flame Cutting and Gouging Processes .... 74
17.8.2 Manual Metal Arc Welding ............................................ 74
17.8.3 Flux-Cored Arc Welding ................................................ 74
17.8.4 Gas Metal Arc (MIG) Welding ....................................... 74
17.8.5 Plasma Arc Welding and Cutting ...................................74
17.8.6 Gas Tungsten Arc (TIG) Welding ..................................75
17.8.7 Submerged Arc Welding ................................................ 75
17.8.8 Aluminothermic Welding (Thermit) ..............................75
17.8.9 Arc Air Gouging .............................................................76
17.9 Materials and Consumables .........................................................76
17.9.1 Source of Fume ..............................................................76
17.9.2 Special Materials ............................................................76
17.10 Coated Metals .............................................................................. 76
17.10.1 Hazards ........................................................................... 76 17.10.2 Control Measures ...........................................................76
17.11 Metal Preparation Processes ........................................................76
17.11.1 Introduction .................................................................... 76
17.11.2 Hazard ............................................................................ 78
17.11.3 Precautions .....................................................................78
17.12 Contaminated Surfaces ................................................................ 78
18 Noise Control .......................................................................................... 79
18.1 Need for Noise Control ...............................................................79
18.2 Effect of Noise on the Ear ...........................................................79
18.3 Noise ............................................................................................ 79 18.4 Noise Sources .............................................................................. 80
18.5 Detection of Hazardous Noise ..................................................... 80
18.6 Noise Measurement .....................................................................80
18.7 Limits on Noise Exposure ...........................................................80
18.8 Noise Control .............................................................................. 80
18.8.1 Control by Elimination and Substitution .......................80
18.8.2 Control at the Noise Source ........................................... 80
18.8.3 Control of Noise Transmission ...................................... 80
18.8.4 Administrative Noise Control ........................................ 80
18.8.5 Control through Personal Protection ..............................80
18.8.6 Audiometry ....................................................................81
18.8.7 Summary ........................................................................81
18.9 Vibration ...................................................................................... 81
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19 Personal Protective Equipment ...............................................................83
19.1 Introduction ................................................................................. 83
19.2 Recommended Equipment for Various Processes .......................83
19.3 Protection of Eyes and Head ....................................................... 83
19.3.1 Purpose ........................................................................... 83
19.3.2 Helmets and Hand Shields ............................................. 83
19.3.3 Protective Goggles ......................................................... 83
19.3.4 Contact Lenses ...............................................................84
19.3.5 Protective Filters ............................................................84
19.3.6 Welding Helmets with Self-Darkening Filters ...............84
19.3.7 Welders' Caps .................................................................85
19.4 Protective Clothing for the Body ................................................. 85
19.4.1 Purpose ........................................................................... 85
19.4.2 Type of Work Clothing ................................................... 85
19.4.3 Gloves ............................................................................ 85
19.4.4 Safety Footwear .............................................................85
19.4.5 Additional Protection ..................................................... 85
19.4.6 Clothing Condition ......................................................... 85
19.5 Screens ......................................................................................... 86
19.6 Respiratory Protection Devices ................................................... 86
19.6.1 Introduction .................................................................... 86
19.6.2 Respirator Types ............................................................. 88 19.6.3 Selection of Equipment .................................................. 89
20 Welding and Cutting in Confined Spaces ............................................... 91
20.1 Introduction ................................................................................. 91
20.2 Supervision, Permits and Precautions ......................................... 91
20.3 Ventilation, Shading and Thermal Insulation ..............................91
20.3.1 Ventilation ...................................................................... 91
20.3.1.1 Shading ............................................................91
20.3.2 Thermal Insulation ......................................................... 91
20.4 Electric Shock .............................................................................. 92
20.5 Flame Cutting, Welding or Preheating ........................................ 92 20.6 The Welder................................................................................... 92
20.7 Emergency Removal of Personnel from Confined Space ............92
20.8 Typical Check List ....................................................................... 93
21 Welding or Cutting in or on Containers .................................................. 95
21.1 Introduction ................................................................................. 95
21.2 Supervision and Approval ...........................................................95
21.2.1 Permits ........................................................................... 95
21.2.2 Gas Freeing Area ............................................................95
21.2.3 Other Considerations ...................................................... 95
21.3 Welding or Cutting Containers which have held Combustibles .. 95
21.3.1 Introduction .................................................................... 95
21.3.2 Identification of Hazard ................................................. 96
21.3.3 Basic Precautions ........................................................... 96
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21.3.4 Cleaning Procedures for Small Vessels ..........................96
21.3.4.1 Water Washing and Rinsing .............................96
21.3.4.2 Hot Chemical Solutions ...................................97
21.3.4.3 Steaming ..........................................................97
21.3.5 Water Filling Treatment ................................................. 97
21.3.6 Non-Flammable Gas Purging ......................................... 98
21.3.7 Large Vessels, Tanks, etc. ............................................... 98
21.4 Welding on Containers and Piping Under Internal Pressure .......98
22 Welding and Cutting on Pressurised Equipment ....................................99
22.1 Introduction ................................................................................. 99
22.2 Precautions .................................................................................. 99
22.3 Procedures ................................................................................... 9923 Welding and Cutting in Hot or Humid Conditions ...............................101
23.1 Introduction ............................................................................... 101
23.2 Heat Stress ................................................................................. 101
23.2.1 Effects of Heat Stress ................................................... 101
23.2.2 Contributing Factors ..................................................... 101
23.2.3 Minimising Heat Stress ................................................ 101
23.3 Extreme Conditions with High Preheat in Confined Space....... 102
23.4 Risk of Electrocution ................................................................. 102
24 Welding in Refineries and Chemical Plants .......................................... 103
24.1 Introduction ............................................................................... 103 24.2 Precautions with Toxic or Flammable Liquids or Gases ........... 103
24.3 Fire Precautions – General ........................................................ 103
24.4 Plant and Personnel ................................................................... 104
25 Welding and Cutting at Heights or Underneath Construction .............. 105
25.1 Introduction ............................................................................... 105
25.2 Electrical Shock ......................................................................... 105
25.3 Head Protection ......................................................................... 105
25.4 Falls or Falling Objects..............................................................105
25.5 Storage of Equipment ................................................................105
25.6 Fire or Burns to Personnel ......................................................... 105
25.7 Lifting of Equipment ................................................................. 105
26 Welding and Cutting Underwater and Under Pressure .........................107
26.1 Introduction ............................................................................... 107
26.2 Proven Equipment .....................................................................107
26.3 Personnel ................................................................................... 107
26.4 Procedures ................................................................................. 108
27 Protection During Weldment Testing .................................................... 109
27.1 Introduction ............................................................................... 109
27.2 Radiographic Testing ................................................................. 109
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27.3 Magnetic Particle Testing .......................................................... 109
27.4 Penetrant Testing .......................................................................110
27.5 Pneumatic Testing......................................................................110
27.6 Hydrostatic Testing ....................................................................110
27.7 Structural Proof Testing .............................................................110
27.8 Leak Testing .............................................................................. 110
28 Welding and Cutting in Machines and Special Locations ....................113
28.1 Introduction ............................................................................... 113
28.2 Welding and Cutting in Machines ............................................. 113
28.3 Special Locations.......................................................................113
28.4 Working in Tanks, Pipelines, Pressure Vessels, Boilers and other Containers .....................................................................113
29 General Industrial Protection ................................................................115
29.1 Introduction ............................................................................... 115
29.2 Ergonomic Considerations ........................................................115
29.3 Thermal Discomfort ..................................................................115
29.4 Lighting ..................................................................................... 115
29.4.1 General ......................................................................... 115
29.4.2 Colour ........................................................................... 116
29.5 Noise and Vibration ...................................................................116
29.5.1 Noise ............................................................................ 116
29.5.2 Vibration .......................................................................116
29.6 Working Posture ........................................................................116
29.7 Manual Handling .......................................................................116
29.7.1 Correct Position for Lifting Tall Cylinders ..................116
29.7.1.1 Rigging ..........................................................116
29.8 Other Ergonomic Conditions ..................................................... 116
29.9 Housekeeping ............................................................................ 116
29.10 Plant and Equipment .................................................................117
29.11 Psychological Factors ................................................................117
29.12 Natural Hazard Elements ...........................................................117
29.13 Personal Gear............................................................................. 117
29.14 First Aid ..................................................................................... 117
29.15 Materials Handling .................................................................... 117
29.16 Personal Hazards .......................................................................118
29.17 Safe Use of Compressed Air ...................................................... 118
Appendix A: References ............................................................................. 121
Appendix B: Statutory Authorities .............................................................. 125
Appendix C: Exposure Standards ...............................................................127
Appendix D: Chemical Symbols ................................................................ 127
Appendix E: Members of WTIA Technical Panel 9 ...................................128
Expert Technology Tools ............................................................................ 129
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W T I A – T E C H N I C A L N O T E 7 P A G E 1
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INTRODUCTION
C H A P T E R 1
In recent times there has been an increasing emphasis
on human values in society generally. In industry, thisdevelopment has made the working environment saferand healthier for all concerned, thus leading to:
a) Reduced industrial accidents and injuries and im-proved health and comfort of workers.
b) Compensation for the complexity and stress of mod-ern industrial life.
c) Reduced loss of time and services of experiencedpeople due to accidents and ill health.
d) Prevention of and reduced consequential damage toproperty and equipment by fire, explosion etc.
e) Higher quality, greater efficiency and increasedproduction and competitiveness.
f) Greater economy both to industry and to the nation.
Industrial laws and regulations are continually beingrevised to reflect these changing social attitudes and worlddevelopments.
Legislation has been improved throughout Australia tocontrol Occupational Health and Safety in the workplace.WTIA has become more deeply concerned with safety
and health in welding1 and is involved in research and
support to industry in this field.
The welding industry consists of a large number ofpeople engaged in an extremely wide range of processesand working conditions where hazards occur if safe prac-tices and adequate precautions are not adopted. However,when carried out in a correct manner, using appropriateequipment working under safe conditions, welding opera-tions present a minor safety and health risk.
Despite the significant progress in Welding Occu-pational Health and Safety, injuries still occur, almostalways involving human error.
This Note has been prepared to complement availableliterature by presenting the latest information on mattersof health and safety in welding. Its objective is to assistall involved, by serving as a basis for the general guidanceof industry and for the training of personnel.
In this Technical Note, it has not been practical togive detailed guidance on every welding health and safetymatter. Where any doubt exists, advice should be soughtfrom suitably qualified health and safety professionals.
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SCOPE
C H A P T E R 2
This WTIA Technical Note gives guidance on health and
safety practices in various welding, cutting and alliedprocesses such as brazing, soldering, pre- and post-weldmaterial treatments and metal spraying, for:
a) The prevention of injury to persons.
b) The prevention of ill-health and discomfort.
c) The prevention of damage to property, equipment andenvironment by fire, explosion etc.
This Note deals with:
i) The basic principles of safe working.
ii) The main hazards and safety measures in welding,cutting and allied processes used in industry.
iii) Precautions required in particular workingsituations.
Other Expert Technology Tools address in more detailwelding electrical safety (Technical Note 22) and OHS&RManagement ( MS02/5-OHS-01).
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PRINCIPLES OF SAFE WORKING
C H A P T E R 3
3.1 Basic ObjectiveAll industrial operations including welding, introducehazards and potential risks which may affect health andsafety if adequate precautions are not taken. Thus, onebasic objective must be to ensure that work is alwayscarried out in a manner to maintain:
a) The health (i.e. well-being and soundness of body)of personnel directly engaged in the work, theirassociates and other nearby persons;
b) The safety (i.e. minimisation of risk) of all personnelinvolved, including those nearby also damage tonearby plant, equipment and the environment.
3.2 Risk AssessmentManagement, unions, employees and other personsdirectly responsible for, or involved in, industrialoperations must be aware of all hazards which could arisein these operations, and the risks to health and safety mustbe eliminated or minimised and controlled.
In order to achieve a safe workplace, it is necessaryto conduct a risk assessment for all procedures, plantand chemicals used in the workplace. The result of acompetent risk assessment should include:
a) Identification of hazards and the way in which the
hazards can cause injury or ill health;b) Assessment of the magnitude of the risk (Job Safety
Analysis); and
c) Control of all hazards to eliminate them or minimiserisks to health and safety.
Note: Risk is the likelihood and consequence offailure.Hazard is a situation with potential to harm.
The risk assessment should be conducted in accor-dance with the guidelines in AS/NZS 4360. It should befully documented and it should be repeated whenever newprocedures or chemicals are introduced in the workplace
or otherwise at least every 5 years.All Australian States have adopted National Model
Regulations and National Codes of Practice for the controlof Workplace Hazardous Substances. These documentsprovide information on risk assessment relevant to exposureto chemicals and fumes. Under some State legislation,
occupational health and safety committees are required
to be set up, in certain circumstances, to discuss healthand safety aspects of the workplace. OH&S Committeesare particularly relevant in organisations involved inwelding, cutting, spraying, brazing or soldering activities.
Two Australian Standards are particularly useful inthis regard, namely:
• AS/NZS 4801 Occupational health and safety manage-ment systems – Specification with guidance for use
This Standard specifies requirements for an occu-pational health and safety management system(OHSMS), to enable an organisation to formulate
a policy and objectives taking into account legisla-tive requirements and information about hazards orrisks.
• AS/NZS 4804 Occupational health and safety manage-ment systems – General guidelines on principles,systems and supporting techniques
This Standard provides guidance on the developmentand implementation of occupational health and safetymanagement systems (OHSMS) and principles, andtheir integration with other management systems.
Hazards, injuries and illness that welding and cuttingpersonnel, including Supervisors and Inspectors, are
exposed to more frequently than other workers include:a) Electric Shock – Contact with electrically live com-
ponents.
b) Radiation Burns – Burns to the eyes or body due tothe welding arc.
c) Thermal Burns – Burns due to weld spatter or hot ormolten materials; or due to burning of clothing etc inoxygen enriched atmosphere.
d) Fire and Explosion – May be due to arc, flame, sparksor spatter or electrical faults in combination withflammable materials, gases or liquids.
e) Eye Injury – Radiation and foreign matter can cause
injury.f) Illness – Illness may result from inhalation of fume
from welding, brazing, metallizing or cutting, fromsurface coating on the material being dealt with,from breakdown of contaminants such as residualchemicals in drums, paint or plastic bonded to metals.
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C H A P T E R 3
g) Asphyxiation – Displacement of oxygen by non-toxicgases can be dangerous.
h) Hearing Impairment – Excessive noise should beavoided.
i) Falls – Working at heights or above openingsincreases risk
j) Other Hazards – Those typically found in generalengineering or in special areas
e.g. radioactive NDT materials.
As part of assessing the risks the effectiveness ofexisting controls should be evaluated.
Suitably experienced staff should conduct the riskassessment. It may be “simple and obvious” (SAO) orcomplex, depending on the nature of the hazards and thethreat posed to health and safety. Professional assistancemay need to be recruited from outside the organisationfor complex situations and serious threats to health.An outcome of the risk assessment may be improvedequipment design or upgraded safety devices. Standardoperating procedures and the nature of induction trainingrequired to operate plant and other tasks should growout of the risk assessment process. Documentation, suchas material safety data sheets (MSDS), and equipmentinstructions used in the assessment process should beavailable for reference.
When assessing the effectiveness of existing controlsand endeavouring to improve them the hierarchy of
controls should be used: i.e.1) Where possible eliminate the use of hazardous equip-ment or methods. Where this is not possible.
2) Substitute safer equipment or methods for the hazard-ous ones.
3) Isolate the hazard from people.
4) Minimise the risk by engineering means.
5) Minimise the risk by administrative means (for exam-ple, by adopting safe working practices or providingappropriate training, instruction or information).
6) Using personal protective equipment as a second lineof defence when other means are not appropriate or
fail e.g. use of gloves.
3.3 Safe Working Practices
Having identified feasible hazards, steps must be imple-mented to prevent damage and accidents or injuries to allpersons in the workplace. Such steps would include:
a) Regular checking and maintenance of equipment.
b) Induction and periodic training of personnel in healthand safety procedures.
c) Ensuring suitable safety devices are installed.
d) Ensuring safe working methods and procedures are
known and observed.e) Ensuring suitable personal protective equipment is
provided and maintained.
f) Periodic review of control procedures.
g) Procedures to ensure that contract workers are awareof workplace hazards before they begin work.
3.4 Responsibility for Health andSafety
Occupational health and safety legislation adopted in allStates imposes responsibility on all employers and people
who have any control of a workplace to ensure that theworkplace is safe and that healthy and safe work practicesare observed. This responsibility is to contractors andvisitors as well as to direct employees. Everyone has aresponsibility to look out for the safety of themselvesand others.
Overall responsibility rests with the highest level ofmanagement. Management should ensure that a healthyand safe working environment is provided and maintained;that safe systems of work are known and followed; and thatall workers receive appropriate OH&S training and areconsulted. Management is also responsible for providing
first aid, and plan for foreseeable emergencies.
All persons in an organisation are involved in someaspect of health and safety and each person must be awareof their responsibility in order to provide a safe workplaceenvironment for themselves, colleagues and others.
In virtually all injuries, one or more of the followingfactors have been involved:
a) Failure to identify a hazard;
b) Failure to minimise or avoid the hazard;
c) Lack of knowledge of the materials being used;
d) Inadequate safety precautions;
e) Poor equipment design or maintenance;
f) Poor working procedures, methods, or supervision;
g) Worker inexperience or lack of knowledge of operation.
3.5 Occupational Health and SafetyPolicy
Senior management has a responsibility to ensure anoccupational health and safety policy is developed andpromoted in the workplace. The OH&S policy shouldoutline the organisation’s approach to workplace healthand safety and commit all levels of management and
supervision to the maintenance of health by facilitating asafe work environment. Implementation of an appropriatehealth and safety programme must occur at all levels of theorganisation. The prevention of accidents and injuries isachieved through good design of equipment and workingconditions and control of employees’ actions. A rationaland consistent approach, which involves workers in riskassessment and in decisions about controls, is the best wayto achieve worker cooperation and compliance. In somestates it is a legislative requirement to consult employeesand unions on occupational health and safety issues.
3.6 Occupational Health and SafetyProgramme
A planned approach to occupational health and safetymust be taken at each plant or work site. A systematicapproach which may include the use of welding specificcheck lists, discussions with employees and detailed
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C H A P T E R 3
consideration of workplace specific problems should beapplied to ensure all foreseeable hazards are identifiedassessed and controlled. The production of fume fromwelding ,cutting and allied processes must be addressedin this process.
Management and Unions at all levels should, byexample and direction, encourage the development ofhealth and safety awareness.
All employees should be suitably trained to undertaketheir work safely by implementing safe practices as anintegral part of their work. A “safety culture” influencingall work should be expected, not the piecemeal applicationof precautions only for the most hazardous procedures.
Adequate first aid, nursing and/or medical facilitiesshould be available. There should be an effective systemfor reporting and investigating any accident, incident near
miss or ill health.
3.7 Safe Working Pre-requisites
It is essential that each worker be advised by his or heremployer of any hazards peculiar to the work environ-ment. It should be recognised that while safety devicesand safe working practices will greatly reduce the numberof accidents which occur, each worker plays a major rolein overall safety.
Hence, each worker and assistant shall be given thefollowing instruction:
a) Know and use the safe working method and proce-dures and when in doubt, ask.
b) Ensure all equipment used is maintained in a safecondition.
c) Make use of appropriate personal protective clothingand equipment.
d) Ensure fume control or ventilation systems functionproperly.
e) Maintain a high standard of housekeeping.
f) Ensure any unsafe condition is made safe beforeworking.
g) Ensure dangerous areas are properly sign-posted,
and enter such areas only when necessary, e.g. highlyflammable or toxic areas.
h) Ensure the use of adequate lighting.
i) Be aware that many occupational hazards are exacerbatedin smokers and never smoke cigarettes on the job.
j) Immediately sign-post or tag with a specially designedtag and report any defective or dangerous equipmentto persons responsible for equipment maintenance.
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C H A P T E R 4
ELECTRIC ARC WELDING, CUTTING AND GOUGING
4.1 Introduction
This Chapter refers to measures which should be adopted
for safety in the use of processes which use an electric
arc between an electrode and workpiece or between
electrodes to develop heat for welding, cutting or gouging.
These processes require particular safety consideration
in respect of the possible hazards in Table 4.1, which are
electrical, radiation, burns, fume and noise.
4.2 Basic Requirements of ElectricalEquipment
All main and ancillary equipment necessary for thesewelding operations should be selected and used on thebasis that it has the required capacity or rating and is safe(Reference 2). This equipment should also comply withthe requirements of electrical supply authorities, whichare usually based on relevant Australian Standards (seealso Section 4.3.2).
Notes:
1. X indicates hazard.
2. Ultraviolet, visible and infra-red radiation.
3. Includes hot objects and particles.
4. Due to consumables, materials and coatings.
5. Shielding gas also introduces risk of asphyxiation.
6. Slight risk of accidental exposure. Limited protection advisable.
7. Fume level is low and welder is remote from arc.
8. Welder is also remote from fume.
9. Noise levels relatively low – main source is motor driven equipment.
Table 4.1 Hazards in Arc Welding, Arc Cutting and Arc Gouging
Process
Arc Exposure
Hazards (Note 1)
Title Abbreviation ElectricShock
Radiation(Note 2)
Burns(Note 3)
Fume(Note 4)
Noise
Manual Metal Arc Welding MMAW OPEN X X X X (Note 9)
Gas Tungsten Arc Welding GTAW or TIG Welding OPEN X X X X(Note 5)
–(Note 9)
Gas Metal Arc Welding GMAW or MIG or CO2 Welding OPEN X X X X(Note 5)
–(Note 9)
Flux Cored Arc Welding
With shielding gas
Without shielding gas
FCAW
OPEN
OPEN
X
X
X
X
X
X
X
(Note 5)
X
–
(Note 9)
–
(Note 9)
Submerged Arc Welding SAW ENCLOSED X –(Note 6) X –(Note 7) –
Electroslag Welding (consumable guide)
ESW–CG EFFECTIVELYENCLOSED
X X(Note 6)
X X(Note 8)
–
Electrogas Welding EGW PARTIALLYENCLOSED
X X X X(Note 8)
X
Plasma Arc Welding PAW OPEN X X X X X
Plasma Arc Cutting
– Open – Water shrouded – Submerged
PAC
OPENENCLOSEDENCLOSED
XXX
X––
X––
X––
XX–
Arc Air Cutting AAC OPEN X X X X X
Arc Air Gouging AAG OPEN X X X X X
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C H A P T E R 4
4.3 Welding Power Sources
4.3.1 Types of Welding Power Sources or Ma-chines
A wide range of direct current (d.c.) and alternatingcurrent (a.c.) types is available for electric arc welding:
a) Low frequency a.c., including mains frequency (50 Hz).
b) High frequency (HF) a.c. Typically 5-6 kHz
c) d.c. (some types of rectifiers impose a mains frequencywave form on the d.c.)
d) Pulsed current (some of the above current types maybe pulsed at, e.g. 25-500 Hz)
Power supplies to provide such current types are:
a) Machines driven by electric motors, petrol or dieselengines.
i) Generators provide d.c. ii) Alternators provide a.c. or, with rectifier, d.c.
b) Transformers which reduce mains voltage to thatrequired for welding.
i) Transformers provide a.c.
ii) Transformer/rectifiers provide d.c.
c) Solid State power supplies (including pulsed weldingunits).
i) Solid State d.c. units.
(ii) Solid State a.c. units.
(iii) Inverter units, a.c. and d.c.
– Square wave low frequency a.c.
– HF a.c. including HF ignition or re-ignition devicesadded on to d.c. or low frequency a.c. supplies.
Many welding machines, especially engine-drivenunits, also provide a 240V a.c. (50 Hz) outlet for power
tools.
Note: The risk of electrocution is primarily relatedto the voltage of an electric source, and also the availablecurrent. With welding machines the available current isalways thousands of times higher than the level that posesa threat to human life. Current of the order of 30mA cancause ventricular fibrillation, heart failure and death.Electrical voltages at both the output and input of thewelding machine may be high enough to inflict seriousdamage, even death. Welders and operators must befamiliar with the risk and must undertake the precautionsdescribed herein and in Chapter 14 to avoid electrocution.
Limiting current flow in people depends on maintaininga high circuit resistance.
4.3.2 Compliance
Australian welding machines are manufactured to AS 1966.Single phase portable welding machines are required toconform to AS/NZS 3195 or equivalent Standards.
Such machines are required to have a clearlyvisible name-plate which legibly and indelibly providesinformation relevant to the operating conditions of themachine. Name-plates should not be interfered with in
any manner.
Working conditions Maximum permitted open circuit voltage (OCV)
Category A environment (AS 1674.2 Clauses 1.3.6.1 & 2.3.1)is where the risk of electr ic shock or electrocution is low. Normalsafe working practice is used. The welder is not in contact withthe workpiece.
d.c. 113 V peak, ora.c. 113 V peak and 80 V r.m.s.
Category B environment (AS 1674.2 Clauses 1.3.6.2 & 2.3.2)is where there is significant risk of the welder being in contactwith the workpiece. Freedom of movement is restricted.
d.c. 113 V peak, or
a.c. 68 V peak and 48 V r.m.s.
Category C environment (AS 1674.2 Clauses 1.3.6.3 & 2.3.3)is where the welder is in contact with the workpiece and therisk of an electric shock or electrocution is greatly increaseddue to the presence of moisture (sweat or water) and wherethe ambient temperature is above 32°C.
d.c. 35 V peak, ora.c. 35 V peak and 25 V r.m.s.
Mechanically held torches with increased protection for theoperator
d.c. 141 V peak, ora.c. 141 V peak and 100 V r.m.s.
Plasma cutting d.c. 500 V peak
Notes:
1. Each power source, complying with IEC 60974-1 that is suitablefor a Category B environment should be marked with a symbolcomprising the letter “S” in a square box. This symbol can be foundin Box 7 of the rating plate or sometimes on the front panel.
2. MMAW power sources to old Standards may supply excessivelyhigh a.c. voltages for Category B and Category C environments.It is necessary to measure the open-circuit voltage to determinesuitability and, if necessary, fit a hazard-reduction device.
Table 4.2 Maximum Open Circuit Voltage Permitted by AS 1674.2 – 2003
3. Power sources to be used in Category C environments are likely to requirea hazard-reducing device (Standard AS 1674.2-2003 Clauses 2.3.3and 3.2.7 – Safety in Welding and Allied Processes Part 2: Electrical).
4. Most GMAW, GTAW and FCAW equipment will meet Category Crequirements because welding voltage and current is switchedwith a trigger switch.
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W T I A – T E C H N I C A L N O T E 7 P A G E 9
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C H A P T E R 4
4.3.3 Open Circuit Voltage
Welding machines generally operate within the followingvoltage range:
• Open Circuit Voltag