Wednesday, June 28, 2006

Safety is key when using gas welding and cutting

The Murex Saffire brand is synonymous with gas welding and cutting safety and is currently celebrating its 50th anniversary: David Fell explains key health and safety considerations.
When using gas welding and cutting equipment, the major hazard is fire which can result in a number of situations and can also lead to the creation of other hazards. The risk of fire or explosion due to the release of fuel gases is the greatest danger to safety in the operating environment. This can be caused by loose or badly connected fittings or an excessive amount of time between turning the gas on and igniting it at the blowpipe, ie inadequate purging.

Operator failure to actually turn the equipment off once the job is completed is also all too often a cause of fire.

Fire can also be spread due to oxygen enrichment if too much of it is released during the cutting operation.

This situation is exacerbated if inadequate ventilation is provided in the workplace.

High pressure oxygen also presents an explosion risk if it comes into contact with oil or grease and therefore no gas equipment should be lubricated in any way.

Good practice in the workplace can help to prevent fire and the risk of fire being generated through sparks can be severely reduced by ensuring adequate distance - at least 10 metres - between the work area and combustible materials.

Good practice would also dictate that a CO2 fire extinguisher and dry powder are within reach.

Fire and hot materials provide a burning risk and therefore the use of proper gloves is essential.

Thicker materials take longer to cool down and it is recommended that metals recently cut should be marked with time and date of work carried out.

Remember too that removing components whilst they are still under pressure could cause them to be propelled with force.

Badly fitting hoses could also, under pressure, flail dangerously in the vicinity of operatives.

Indeed, in terms of physical personal protection for the welder, there are risks to all parts of the human body if incorrect procedures are not properly followed.

General physical damage and back strain can result from falling gas cylinders or attempting to move them incorrectly.

Even general untidiness - bad house-keeping - in the workshop creates a risk of tripping and sustaining injury.

Think carefully too about eyes, ears and respiration.

Intense glare and ultra-violet radiation from the welding or cutting process can be prevented through the use of goggles manufactured to EN 75.

The lens must always be appropriate for the strength of the operation being attempted in accordance with EN166/169.

The lens will protect from both glare and stray sparks.

For those who wear normal glasses, goggles are available - some have a secondary clear glass lens for protection when the filter lens is removed to see the workpiece.

Heat and radiation can be a problem when heating or cutting thick or heavy sections of material.

In these circumstances, normal gloves and overalls may not be sufficient and special insulated clothing may be required.

Furthermore, local fume extraction equipment placed down wind of the operation will help both with radiation and fume problems caused by heating lead or zinc coatings as well as galvanised material.

It is common practice to use a personalised fresh air unit for these operations today.

The consequences of flashback, backfire and sustained backfires can be devastating and a whole article could be written on this subject alone.

Suffice to say here that correct working practices (purging of hoses, right choice of cutting nozzle, correct working pressures) are absolutely essential.

However, sometimes the cause of flashback and backfire is beyond the control of the operator and it is therefore vital that the correct flashback arrestors and nonreturn valves are fitted.

In summary, proper personal protection and the promotion of general safety when gas welding and cutting, is imperative.

There is legislation, standards and guidelines to be followed which all companies must be aware of.

There is also the whole area of risk assessment to be considered and complied with.

These factors demand that employers and operators must have adequate knowledge of the process being undertaken and the equipment at their disposal to undertake the work.

Operatives must be provided with proper head to toe protection that not only provides the correct level of protection for the job in hand, but is also comfortable to wear and is worn properly.