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Introduction
Welding and the use of associated equipment is a hazardous activity that can expose workers to many dangers. This resource provides guidance on the safe use of compressed gases and equipment in gas welding and provides information on hazards & risks and the protective measures needed to control them.
For easy reading within the resource, the single word ‘welding’ has been used to indicate all types of welding, soldering and flame cutting activities.
Causes of ill health
Common causes of ill health associated with welding are:
- Inhalation of harmful welding fume.
- Unsafe handling of workpieces and welding equipment, particularly gas cylinders.
- Noise, particularly from plasma arc cutting, gouging operations and weld preparation.
- Burn from ultraviolet radiation, including ‘arc eye’.
- Vibration during grinding for weld preparation.
- Discomfort from heat and uncomfortable postures.
Causes of accidents
Common causes of accidents associated with welding are because of:
- Falling gas cylinders.
- Particles entering unprotected eyes during chipping after welding.
- Electric shocks from arc welding equipment.
- Fires started by flames, sparks and hot material from welding and cutting processes.
- Fingers being crushed between the electrodes of fixed resistance welding machines.
Safety measures
The following key safety measures should be used to reduce the risk of ill health and accidents when welding:
- Suitable extraction equipment.
- Appropriate protective clothing e.g. overalls, protective apron, gloves, safety boots & respiratory protection.
- Welding screens and eye protection (BS 679) to prevent arc eye.
- Local isolation switch.
- Welding set transformer.
- Workpiece earth when required.
- Insulated electrode holder.
- Insulated box for electrode holder.
- Proper cable connections.
- Suitable fire extinguisher easily accessible.
- Insulated and robustly constructed welding leads big enough to carry the current safely.
- Residual current devices which may enhance safety.
Work in confined spaces and on large structures supported on manipulating devices will need special precautions.
Best practice
Individuals using welding equipment should be experienced and competent in its use and should adhere to the following best practice:
- Know how to use extraction equipment.
- Do not wear metallic jewellery, rings, or watch straps.
- Know how to change electrodes safely.
- Use an insulated box or hook to rest the electrode holder NOT the face shield, clothing or rags.
Maintenance
Maintaining welding, ventilation and protective equipment is essential and the recommendations below will help ensure the continued safety and wellbeing of those who use the equipment.
- Have local exhaust ventilation regularly examined and tested by a competent person.
- Examine respiratory protective equipment thoroughly every month (testing air fed equipment at the same intervals, checking the volume and quality of breathing air supplied)
- Examine flexible gas and oxygen hoses regularly and replace damaged ones, never repair them with tape.
- Check and maintain other safeguards as appropriate.
Never apply heat to containers, tanks or drums which may contain flammable residues. Either use cold, non-sparking methods or clean and make them gas free first.
Storage and use of gas cylinders
The storage and use of welding gas cylinders should always be done safely and the following steps are recommended to reduce the risk of accidents occurring.
- Store full and empty cylinders in a safe, well-ventilated place.
- Never keep cylinders below ground level next to drains, basements and other low-lying places – heavy gases will not disperse easily.
- Do not leave charged hoses where ventilation is poor for extended periods in case of leaking gases or oxygen.
- Some gas cylinders, for example acetylene, contain liquid – store them with their valves uppermost.
- Protect cylinders from damage, for example by chaining unstable cylinders in racks or on trolleys.
- Provide suitable trolleys with restraining chains for moving oxyacetylene sets and other cylinders.
- Minimise damage by using the correct hoses, clamps, couples and regulators for the gas and appliance being used.
- Never apply grease oil or other lubricants to oxygen fittings.
- Prevent damage to hoses. Do not run them unprotected, for example, across traffic routes.
- Turn off cylinder valves at the end of each day’s work.
- Change cylinders away from sources of ignition in a well-ventilated place.
- Minimise welding flame ‘flash-back’ into hoses or cylinders by using correct lighting up and working procedures and by fitting effective non-return valves and flame arresters.
- Use soap or detergent and water solutions to test for leaks – never a flame.
- Do not use oxygen as a substitute for compressed air to power pneumatic tools.
Risks from fume
Fume from welding varies greatly in composition and concentration. Different jobs lead to different levels of exposure to different substances. Fume from welding may cause:
- Dryness of the throat, tickling, coughing, tightness of the chest and difficulty in breathing.
- An acute flu-like illness known as metal fume fever.
- Long-term changes in the lung.
Welding or cutting processes releasing the greatest quantities of harmful fume include:
- Work on metallic coatings such as cadmium or zinc plating and chromium, manganese, cobalt and/or nickel hard surfaces.
- Work on painted surfaces which contain lead, zinc, chromium or cadmium pigments.
- Mechanised flame cutting.
- Flame gouging.
- Frequent and regular manual metal arc welding.
- Flux cored electrode welding.
- Higher current metal inert gas shielded welding particularly on stainless steel, and aluminium, copper, nickel and their alloys.
- Oxygen arc cutting and gouging.
- Using cadmium-containing solder.
Minimise risks
Safety measures can be used to minimise the risks associated from fume and include the following recommendations:
- Avoid welding and flame cutting, using other bonding and cutting techniques where reasonably practicable.
- Use safer filler materials, such as cadmium free silver solder.
- Control exhaust fume by using local exhaust ventilation.
- Use respiratory protective equipment.
- Ensure workshops have enough low-level inlets and high-level outlets for air changes
- Don’t weld near cleaning processes using chlorinated solvents as the heat and arc from welding may break down the solvents into more harmful substances. Recommended safe distance is 10m for most welding, 20m for aluminium.
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