Safety Aspects of Welding

             

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.

 

                               

Figure 1 : The wrong (left) and right (right) way to carry out arc welding processes.

 

Personal Protection.

            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.

 

Protective Clothing.

Protect persons in the vicinity of the arc by means of non-reflective curtains or screens .

 

 

Figure 2 : Protective Screens.

 

Figure 3 : Protective Clothings.

 

 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,

1. ultra-violet: damage to skin and eyes(inflammation of the cornea and cataracts)
2. 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.

 

 

 

Fire and Explosion Hazards

 

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

 

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.

 

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).

 

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.

 

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).