In this article, the general hazards which may arise when carrying out welding and related operations, are identified. In subsequent articles, guidelines will be given on the principal health and safety considerations for each welding process.
Regulations and codes of practice
The Health and Safety at Work etc. Act, 1974, requires that the risk to workers of injury or ill health due to work activities should be minimised and there are many national and international Regulations, approved Codes of Practice and Standards covering the safe operation of welding and cutting systems. Those of more direct interest to welders and welding engineers are listed at the end of the article. In the UK, particular attention should be given to the Health and Safety Executive (HSE) publications.
Safe assembly
Although welding and cutting operations require special considerations, personnel should be aware of the general health and safety requirements of related fabrication activities. Safe places and systems of work include handling and housekeeping.
The wrong and right way to carry out arc welding processes
Safe control of arc welding
Arc processes produce fumes which contaminate the atmosphere surrounding the work. Precautions must be taken to eliminate the risk of electric shock. Actions to ensure safe practice and accident avoidance will be presented in a subsequent issue.
Personal protection
Fume
Firstly, can exposure can be prevented by eliminating the generation of welding fumes altogether? If not, fume will have to be controlled at source, perhaps by local ventilation. Respiratory equipment should not be used until all other possibilities have been eliminated. In general, respiratory protective equipment is used only as an interim measure but there will be circumstances where, in addition to ventilation measures, personal protection may be necessary.
Arc radiation
The arc can generate three types of radiation; ultra-violet, visible and infra red (heat) radiation which can be injurious in the following ways:
- ultra-violet: damage to skin and eyes(inflammation of the cornea and cataracts)
- visible light: dazzle eyes and impair vision
- infra-red: damage skin and eyes
Radiation may be direct or reflected from shiny or other reflective surfaces.
Safe practice and accident avoidance
- Protect face and eyes using a suitable welding shield equipped with eye protection filter
- Protect the body by wearing suitable clothing
- Protect persons in the vicinity of the arc by means of non-reflective curtains or screens
Fire and explosion hazards
Fire
There is an inherent hazard associated with gas processes. Additionally, both flames and arcs in welding and cutting may create a fire hazard. When fighting a fire, the appropriate fire extinguisher for the type of material must be used. Class C fires, for example those involving flammable gases such as acetylene, are best extinguished by cutting off the gas supply. Water and foam extinguishers should not be used on fires near to live electrical equipment.
Safe practice and accident avoidance
- Remove flammable material from the welding area
- Cover remaining flammable material with fire resistant material
- Before welding, check that the appropriate fire fighting equipment is at hand
- After welding, observe surrounding area of the work for an adequate period of time (suggest about one hour)
Explosion
There is danger of explosion when welding a container which previously contained explosive or flammable substances; explosive material can be trapped in grooves, seams, riveted joints or behind scale.
Safe practice and accident avoidance
Before welding, the following actions should be carried out:
- Remove explosive material by steaming or boiling out
- If the explosive material cannot be completely removed, fill the container with water, an inert gas or pass steam through it
Welding in confined spaces
Special care should be taken in case toxic fumes or gases build up. In gas shielded welding operations, there may be a danger from asphyxiating because of oxygen deficiency. A suitably qualified person should assess the risk, determine the steps required to make the job safe and recommend precautions to be taken during the welding operation itself.
Safe practice and accident avoidance
- Ensure adequate ventilation and, if necessary, use personal protection
- Ensure that any used vessel does not contain flammable, poisonous or explosive material
- Ensure gas cylinders are not taken into the enclosed space
- Check equipment for gas leaks
- Ensure trained personnel are in attendance to deal with any emergency
- Check by rehearsal that the worker can be rescued, should an emergency arise
- At the end of work periods, shut off all gas supply valves and withdraw hoses and equipment
Awareness of welding environments
Noise
As a general guideline, wherever it is difficult to carry on a conversation, it is likely the noise level is unacceptable. HSE recommendations are that when the noise reaches 85dB(A), employers are required to offer hearing protection to their employees. As continuous exposure for 8 hours or more to a noise level at or above 90dB(A) is injurious, hearing protection is mandatory when this level is reached. Higher levels can be tolerated for short periods but impulsive or peak noise in excess of 140 dB should not, where practicable, be exceeded.
As damaging noise levels can be generated from some welding processes and allied activities, welders will usually need hearing protection. For example, hand grinding may emit noise levels of the order 108dB(A).
Safe practice and accident avoidance
If noisy equipment or processes cannot be avoided, one or more of the following alternatives may apply:
- Insulate the noise source as far as possible by fitting silencers or sound proof enclosures
- Insulate the operator from the noise source by wearing suitable ear protection
- Where practicable, do not exceed impulsive noise levels in excess of 140 dB
Vibration
Portable tools which produce excessive vibration, may cause damage to the hands, often called 'white finger' (Raynaud's phenomenon). As the hazard is particularly acute with tools such as chipping hammers which rely on impact, their use must be minimised.
Safe practice and accident avoidance
- Avoid or limit the use of equipment with excessive vibration
- Keep the hands warm
- Avoid an excessively strong grip when holding the tool
Designation of hazardous areas
It may be necessary to restrict entry to the work area to authorised persons wearing suitable protection. Warning signs will be required for the following hazards:
- For welding and cutting processes, where the arc is exposed, the warning for eye protection should refer to the hazard of arc radiation
- 'Ear Protection Areas' where 8 hours exposure to noise levels is at, or above, 90 dB(A).
Further information
The following are useful standards and codes of practice relating to health and safety in welding and allied processes:
HSE publications
EH 55,1990, The control of exposure to fume from welding and allied processes
HS(G) 53, 1990, Respiratory protective equipment: a practical guide to users
HS(G) 56, 1990, Noise at work, noise assessment, information and control
HS(G) 118, 1995, Electrical safety in arc welding
British standards
BSEN 169: 2002 Personal eye protection equipment used in welding and similar operations
BSEN 470-1:1995 Protective clothing for welders
The information was prepared in collaboration with Roger Sykes, Health & Safety Executive, Newcastle upon Tyne.
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This Job Knowledge article was originally published in Connect, April 1997. It has been updated so the web page no longer reflects exactly the printed version.