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GUI0145/01/04.11 1

Metal welding safety

Guidance Note

BackgroundMetal welding involves the application of heat to join two metals together. The heat is generated through electric currents (arc welding) or gases (gas welding).

Welding is undertaken in many industries for purposes including the manufacture of machinery, tools and equipment and repair and maintenance work. Those most at risk of welding-related injuries are operators producing industrial or commercial machinery and fabricated metal products.

Main hazardsThe most common causes of injury from welding result from:

• manualhandling

• fire,explosionsandradiationexposure

• electricshock.

Employers must provide a safe work environment for workers by implementing adequate controls for all identified workplace hazards.

How to use the tableThetableoverthepagelistsandshowsexamplesofthemain hazards related to welding. It also includes the possible consequences of the hazard and provides a list of recommended controls. The zone numbers in the table refer to what is shown in the picture below.

1

2

3

4

5

6

Zone 1: Welding equipment Zone 2: The welding process Zone 3: Work pieces being welded Zone 4: Welding with gases Zone 5: The operator Zone 6: Welding workspace

Note: This guidance note does not include information on welding in confined spaces or under water.

June 2011

Practical advice for employers on controlling hazards when welding.

Guidance Note Metal welding safety

2

Hazard Possible consequence Recommended controls

Zone 1: Welding equipment

Welding equipment (body, hoses and hand gun) is worn, damaged or poorly maintained.

Welding equipment can fail. Failure of hoses and fittings allows gas to escape resulting in afireorexplosion.

Damaged electrical components can result in electric shocks to the operator.

• Regularly inspect and maintain welding equipment (including the insulation).

• Repair or discard damaged or worn parts (giving consideration to decommissioning processes).

• Store welding equipment where it cannot be damaged (particularly for portable or mobile oxy-fuelgaswelding).

Welding leads and hoses are not uncoiled before use.

High currents passing through coiled leads can result in damage from heat increasing the risk of electric shock.

• Completely uncoil welding leads before use.

Worn or damaged electrical leads, power points and extensioncords.

Electrical faults can cause electric shock or, where they interact with flammable substances, burns.

• Use cables that are appropriate for the current being carried.

• Maintainleads,powerpointsandextensioncordsingood working condition.

• Ensure installation and servicing of electrical supply circuits is done by a qualified electrician.

• Regularly inspect insulation on cords and remove damaged cords from use.

The open circuit voltage is not reduced to a safe level.

Operator receives an electric shock.

• Ensure the open circuit voltage is within safe limits and, where necessary, use voltage limiting devices (VLDs).

Welding currents are not grounded.

Operator receives an electric shock.

• Ensure proper grounding methods have been applied within the welding area and they are in good working order.

Zone 2: The welding process

Lack of familiarity with the gases used or fumes produced during welding processes.

Workers can become ill if dangerous fumes are not removed from the workplace.

• Ensure familiarity with materials being used (such as gases, base metals, coatings and cleaners) and their possible health impact. Where necessary, engage a suitably qualified person such as an industrial hygienist to assist.

Exposuretoweldingarc. Operatorscanexperienceburnsto skin and eyes from radiation (ultraviolet and infrared).

• Wear auto darkening helmets.

• Carry out welding processes in booths or use welding screens to protect nearby workers.


3


Fumes produced during welding processes.

Workerscanexperienceeye,skin and respiratory system irritation, nausea, headaches and dizziness.

Dust and fumes can cause serious lung diseases and increase the risk of asthma and cancer and possibly lead to asphyxiation.

• Ensure fumes and gases are removed from the breathing zone. Eg. Ventilation.

General ventilation

• When used by itself, ensure general ventilation removes welding fumes from the breathing zone (including on days with little wind).

Mechanical ventilation

• Ensure the speed of the systems is great enough to draw fumes out of the breathing zone.

• Where the fumes are drawn downward, ensure work pieces do not cover too much of the ducting ortheexhausteffectwillbelost.

• Ensure mechanical ventilation removes fumes close tothesource.Flexibleductingallowsthecapturedevice to be moved to the appropriate position (see picture).

• Ensure that fumes drawn outside are not able to re-enter the workplace.

• Ensure mechanical ventilation units are maintained in good working order.

• Undertake health surveillance to monitor workplace exposuretohazardoussubstances.

Zone 3: Work pieces being welded

Welding objects or plant that contain/have contained (with traces remaining) flammable or explosivesubstancesorgases.

Object being welded can explodeorcreateafireresultingin fatalities, burns or fractures to operator or nearby workers.

• Ensure welding activity is not performed on objects or plant in which a flammable substance has been manufactured, used, handled or stored unless it is completely free of the substance or gas.

If the contents of the object or plant are unknown, it should be assumed that it contains flammable or explosive substances.


4


Welding objects are coated in unidentified paints or metal coatings.

Dangerous fumes can be generated when welding some coatings. This can cause respiratory distress, eye or skin irritations, headaches or nausea.

• Identify coatings on work pieces before commencing work and take actions to prevent exposuretodangerousfumes(thiswillvarydepending on the coating).

Pieces of slag or molten metal come away from work pieces and make contact with leads and hoses.

Operators can receive an electric shockoranexplosioncanoccur.

• Where possible, elevate cables, hoses and wires. Forexample,suspendthemonhangersorswingarms.

Zone 4: Welding with gases

Flames travel back down the gas hoses (known as flashback).

Flashbackcancauseexplosionsand fires, burning the operator.

• Ensurehosesarefittedwithflashbackarrestorsat both ends.

Movement of heavy gas cylinders.

Regular movement or replacement of gas cylinders requires awkward postures and high forces and may cause muscle sprains and strains.

• Considerpipinggasesintothebuildingnearworkstations to eliminate the need for operators to manually handle cylinders (see picture).

• Usemechanicalaidstomovecylinders.

• Considerusinggasesthatrequirelessfrequentreplacement.Forexample,LPGlastslonger than acetylene.

Gases are stored with incompatible chemicals or in inappropriate locations.

Gasesmayexplodeinjuringoperators and nearby workers.

• Storegasesinaccordancewiththeirclassification and quantities (refer to the Australian Dangerous Goods Code).

• Storegascylindersinwellventilatedareasandprotectedfromweatherbutnotattheexpenseof ventilation.


5


Gas cylinders are not secured in location.

If a cylinder falls over the valve at the top can be knocked off causing the cylinder to become a dangerous projectile that can strike and injure operators.

Workers can also inhale the escaping gases which can damage the respiratory system orcauseasphyxiation.

• Storegascylindersinasafelocationthatisprotected from the immediate welding area.

• Securecylindersusinggascylinderholders or anchored chains to prevent tipping over (see picture).

Zone 5: The operator

Operatorsareinexperienced (eg apprentices, trainees and young workers) or not trained to perform welding safely.

Inexperiencedorpoorlytrainedoperators are more likely to make mistakes increasing risk of injury.

• Ensureoperatorsdemonstratecompetency and hold an appropriate certificate or have had requiredtrainingorexperience.

Lack of or inappropriate supervision.

Unsupervised operators are at greater risk due to unsafe work practices.

• Ensureoperatorsareadequatelysupervised by a certified welding supervisor.

Welding is performed on the ground or requires awkward positions.

Awkward postures can result in muscular sprains and strains or fatigue.

• Positionworkpieceinthebestworkingzone,between the shoulders and knees (eg using height adjustable benches or supports).

High risk

Medium risk

Low risk


6


Manual movement of heavy materials and work pieces.

Operatorcanexperiencemuscular sprains and strains or fatigue.

• Designtheworkenvironmentsothatexcessivephysical effort is not required to move materials. Eg use mechanical aids or adjustable rotator or fixture(jigs)toalignparts.

Electrodes or welding wire are touched with bare hands when in the holder or welding gun.

Operator will receive an electric shock if these are touched with bare skin.

• Ensureelectrodesandweldingwireintheirholder or the welding guns are never touched with bare hands.

Holding welding gun under the armpit.

Electric shock (sweating increases conductivity).

• Neverholdweldinggunsunderthearmpit.

Repetitive squeezing of welding handles or triggers.

Operatorscanexperiencestrainsfrom frequently performing the same task.

• Automatetheweldingprocessorreorganiseworkpracticestoeliminateexposure.

Lack of, inappropriate or damaged personal protective equipment (PPE) or respiratory protective equipment (RPE) worn by operator and nearby workers.

Cracked or damaged helmets or inappropriatefilterscanexposeoperators to radiation causing eye damage.

Synthetic clothing can easily catch fire. Molten metal and sparks can enter pockets and cuffs or make contact with bare hands resulting in burns.

Dust and fumes can cause serious lung diseases increasing the risk of asthma and lung cancers.

• Ensure operators are provided with and use task appropriate PPE and RPE that is in good condition.

• Ensure workers are trained on how to correctly use their PPE and RPE.

• Store PPE close to workstations where it can’t be damaged or contaminated.

• Ensure operators wear:

– task appropriate auto darkening helmets

– fire resistant protective clothing, such as raw hide operators jacket, cotton heat vests and long cuff welding gloves/gauntlets

– insulating gloves

– rubber soled boots designed for welding tasks

– securely fitting RPE where RPE is assessed as necessary.

Zone 6: Welding workspace

Welding in a non-designated area.

Open flames and sparks from welding can ignite flammable substances produced from work nearby causing burns or fractures to workers.

• Wherepossible,setupdesignatedweldingareas.

• Ensureacompetentandexperiencedpersonhasundertaken a hot work permit prior to commencing welding processes.

Welding in an uncontrolled open air environment.

Changes in weather can cause anexplosionifgasestravelintoareas with an ignition source.

Operators can receive an electric shock if welding equipment gets wet.

• Assesstheenvironmentwheretheweldingistobe done before work starts and if necessary change the location.

• Makesureweldingareaandequipmentisdrybefore work starts.

• Neverweldnearincompatiblesubstances(including where they are stored).


7


Welding near flammable substances or materials. This includes objects, machinery or equipment that contain, or has contained flammable substances, or in areas containing dusts, grains, or paperwork.

Substances near the object beingweldedcanexplode or catch fire, or welding sparks can ignite materials or dust in the work area resulting in burns or fractures.

• Neverweldnearflammablesubstancessuch as those in objects, machinery or equipment unless they are rendered free of the substance.

• Removeflammableortoxicmaterialsfrom the welding area before work is carried out.

• Inspectandcleanworkareasregularly.

Workspace is untidy. For example,cablesrunningacrossthe floor and waste not regularly removed.

Workers can trip over objects (cables, work materials) or slip on spills.

• Organisetheworkareastominimisethenumberof cables and position them where they cannot be stepped or tripped on. Eg suspend hoses off the ground (see picture) or coil hoses when not in use.

• Considerinstallinghosesandcablesunderground.

• Useboom-mountedwirefeederstoeliminate the lifting of feeders and cable cutter off ground (see picture).

• Regularlycleanworkareastoreduceclutter and prevent the build up of flammable materials including dust.


8


Welding on wet or poorly insulated floor.

Operator can receive an electric shock.

• Wherepossible,workshouldbeperformedondry insulated surfaces such as wooden platforms or insulating mats.

Excessivenoisefromweldingprocesses

Operator and nearby workers can suffer hearing loss.

• Wherepossible,controlnoiseatthesource.

• Provideoperatorswithappropriatehearingprotectionforthelevelofnoiseexposure.

• Wherenecessary,undertakeaudiometrictestingof both the work area and operators and put controls in place.

Lack of, or poorly maintained, emergency management plan and emergency equipment (including lack of training on how to use it).

Operators cannot effectively respond in emergency situation suchasexplosionsorfire,andwill receive burns or fatal injuries.

• Ensuretheworkplacehasfiresafetyequipmentsuchasalarmsystems,fireextinguishers,hydrants, hoses and fire blankets.

• Regularlyinspectandtestfiresafetyequipmentas per equipment requirements.

• Haveanemergencyplaninplace.

• Ensureworkershavebeentrainedinemergencyprocedures.

Further information and guidanceContact the WorkSafe Victoria Advisory Service on 1800 136 089 or go to worksafe.vic.gov.au

Related WorkSafe publications• Aguidetosafetyinthemetalfabricationindustry

• MetalFabrication–Improvinghealthandsafetythroughlayoutanddesign

• AS1674.1Safetyinweldingandalliedprocesses.Part1:Fireprecautions

• AS1674.2Safetyinweldingandalliedprocesses.Part 2: Electrical

• AustralianDangerousGoodsCode

Note: This guidance material has been prepared using the best information availabletotheVictorianWorkCoverAuthority,andshouldbeusedforgeneraluseonly.Anyinformationaboutlegislativeobligationsorresponsibilitiesincludedinthismaterialisonlyapplicabletothecircumstancesdescribedinthematerial.Youshouldalwayscheckthelegislationreferredtointhismaterialandmakeyourownjudgementaboutwhatactionyoumayneedtotaketoensureyouhavecompliedwiththelaw.Accordingly,theVictorianWorkCoverAuthoritycannotbeheldresponsibleandextendsnowarrantiesastothesuitabilityoftheinformationforyourspecificcircumstances;oractionstakenbythirdpartiesasaresultofinformation contained in the guidance material.

metal welding safety - content.api.worksafe.vic.gov.au · guidance ote metal welding safety 5...

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