adminwelding is to be undertaken safely.
There are two main types of welding, namely gas and arc welding.
Arc welding uses a powerful electric arc to make and repair plain, coated or treated metal items.
Hazards related to arc welding include sparks, molten or hot metal, metal fumes, fire, toxic gases, electricity and infrared and ultra-violet radiation.
The health risks include arc-eye, sunburn, infertility and metal fume fever, which arise from being exposed to infrared and ultra-violet rays and fumes from metals such as zinc, brass, cadmium, lead, copper, manganese, nickel or chromium that may be coating the item being welded or the filler rod.
Employees involved in welding operations should be sent for pre-employment, periodic and post-employment medical examinations to monitor exposure levels to such metal fumes and other toxic gases arising from welding processes.
Legal safety requirements in relation to welding, flame cutting, soldering, blazing and allied operations in factories are contained in the Factories and Works Act Chapter 14:08 Machinery Regulations (RGN Number 302 of 1976).
The regulations cover protective clothing, insulation of apparatus and provision of welding screens.
They also cover ventilation requirements when welding in confined spaces, and precautions to be observed when operating in potentially dangerous situations.
The regulations also deal with safety precautions, inspections, maintenance and repair of electrical equipment and machinery.
When installing an electric-powered arc welding machine, the equipment must be earthed.
It should be placed on an independent circuit with the correct-sized fuse or circuit breaker.
Overloading circuits or improper installation can lead to fire, a ground fault or equipment failure.
A safety disconnect switch should be mounted near the user or work area. Diesel or gas powered arc welding machines should be used in well-ventilated areas to control combustion fumes.
Do not add fuel to the engine while it is running or near an open flame. Stop the engine and lock out the ignition before performing maintenance or repairs.
To protect one’s body from burns due to arc welding heat, ultraviolet light (UV), molten metal, and sparks, a welder should wear dark coloured coveralls with long sleeves and trouser legs.
The coveralls should be fire retardant, cuffless, and pocketless, with no holes, tears, or worn spots. Seams should be inside, so as not to trap sparks or molten metal.
A skull cap that protects the head and hair should be worn. Leather gauntlet gloves and safety boots are important to protect the hands and feet.
Hearing protection should be worn in noisy environments and to keep sparks out of the ears. Goggles or safety glasses and welding helmets or shields must be used to protect the eyes from flying sparks, chipped slag and ultra-violet light.
Welding helmets and shields should be non-reflective and free of cracks, gaps, and openings.
According to the Factories and Works Act Machinery Regulations, one should weld inside a screened area to prevent injury to the eyes of any person in the vicinity, as well as to reduce the possibility of fires being started by flying objects.
Portable screens, shields and anti-flash goggles can also be used to protect visitors and other workers.
Arc welding can reach temperatures greater than 1 600 degrees Celsius, posing a fire and explosion hazard.
It is important not to arc weld near flammable or combustible materials or liquids.
Welders should avoid welding, cutting or hot work on used drums, barrels, or tanks, where residual fumes can ignite and explode.
They should weld rather on a firebrick surface, concrete or other fire-resistant flooring surrounded by spark curtains.
Cracks in the flooring should be filled to prevent sparks and hot metal from entering and smouldering.
An ABC fire extinguisher, fire blanket and first aid kit should be available at all times.
It may be necessary to set a “fire watch” to ensure that a fire does not start.
To avoid electric shocks from arc welding, an insulating mat should be used when welding steel or other conductive materials. If the welder is welding in a wet or damp area or perspiring heavily, he should wear rubber gloves underneath the leather gloves. Welding cables should be kept clean and intact and positioned so that sparks or hot metal do not fall on them.
Arc welding should be done in well-ventilated areas.
Welding metals may be hazardous or lead to an oxygen deficient atmosphere. It is best done in a ventilation hood exhausted to the outside.
When welding or cutting metals with hazardous coatings or treatments, it is best to use a supplied-air respirator or a respirator with a special cartridge to filter specific metal fumes.
Use respiratory protection for galvanised items and metals, coatings and fluxes that contain fluorine compounds, zinc, lead, beryllium, cadmium and mercury.
Some cleaning and degreasing compounds may also be hazardous.
According to the Factories and Works Act Machinery Regulations: “No one shall permit electric welding to be undertaken in wet or damp situations, in closely confined places or inside metal vessels unless the operator is completely insulated by means of boots, gloves or rubber mats and at least one other person who has been properly instructed remains in attendance during the operation.”
Introducing a permit to work system for work carried out in confined spaces such as vessels should help control such situations.
Despite the hazards, welding can be carried out safely, if adequate precautions are taken.
What is needed is a thorough ongoing education and training programme, comprehensive medical surveillance, provision of adequate and appropriate personal protective equipment and clothing, and consistent enforcement of welding standards.
Talking Social Security is published weekly by the National Social Security Authority as a public service. There is also a weekly radio programme, “PaMhepo neNSSA/Emoyeni le NSSA”, discussing social security issues at 6.50pm every Thursday on Radio Zimbabwe and 6.50pm every Friday on National FM. Readers can e-mail issues they would like dealt with in this column to [email protected] or text them to 0735 041 278. Those with individual queries should contact their local NSSA office or telephone NSSA on (04) 706517-8 or 706523-5.
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