Adapted from 3rd edition, Encyclopaedia of Occupational Health and Safety.

The domestic electrical appliance industry is responsible for the manufacture of a wide-ranging variety of equipment including appliances designed for audio-visual, cooking, heating, food preparation and storage (refrigeration) uses. The production and manufacture of such appliances involve many highly-automated processes which can have associated health hazards and disease patterns.

Manufacturing Processes

Materials used in the manufacture of domestic electrical appliances can be categorized into:

1. metals which are used typically for electric conductors in cables and appliance structure and/or framework
2. dielectrics or insulating materials used for prevention of accidental contact with live electrical equipment
3. paints and finishes
4. chemicals.

Examples of the materials included in the four categories referred to are shown in table 1.

Table 1. Examples of materials used in the manufacture of domestic electrical appliances

Note: Lead and mercury are decreasingly common in domestic electrical appliance manufacturing

The materials used in the domestic electrical appliance industry must satisfy exacting requirements, including the ability to withstand the handling likely to be encountered in normal operation, the ability to withstand metal fatigue and the ability to be unaffected by any other processes or treatment which could render the appliance dangerous to use either immediately or after a prolonged period of time.

The materials used in the industry will often be received at the appliance assembly stage having already undergone several manufacturing processes, each of which is likely to have its own hazards and health problems. Details of these hazards and problems are considered under the appropriate chapters elsewhere in this Encyclopaedia.

The manufacturing processes will vary from product to product, but in general will follow the production flow shown in figure 1. This chart also shows the hazards associated with the different processes.

Figure 1. Manufacturing process sequence & hazards

Health and Safety Issues

Fire and explosion

Many of the solvents, paints and insulating oils used in the industry are flammable substances. These materials should be stored in suitable cool, dry premises, preferably in a fireproof building separate from the production facility. Containers should be clearly labelled and different substances well separated or stored apart as required by their flashpoints and their class of risk. In the case of insulating materials and plastics, it is important to obtain information on the combustibility or fire characteristics of each new substance used. Powdered zirconium, which is now used in significant quantities in the industry, is also a fire hazard.

The quantities of flammable substances issued from storerooms should be kept to the minimum required for production. When flammable liquids are being decanted, charges of static electricity may form, and consequently all containers should be grounded. Fire-extinguishing appliances must be provided and the personnel of the storeplace instructed in their use.

Painting of components is usually carried out in specially built paint booths, which must have adequate exhaust and ventilation equipment that, when used with personal protective equipment (PPE), will create a safe working environment.

During welding, special fire precautions should be taken.

Accidents

Reception, storage and dispatch of raw materials, components and finished products can give rise to accidents involving trips and falls, falling objects, fork trucks and so forth. Manual materials handling can also create ergonomic problems which can be alleviated by automation whenever possible.

Since numerous different processes are employed in the industry, the accident hazards will vary from shop to shop in the plant. During component production there will be machine hazards in the use of machine tools, power presses, plastics injection-moulding machines and so on, and efficient machinery guarding is essential. During electroplating, precautions must be taken against splashes of corrosive chemicals. During component assembly, the constant movement of components from one process to another means that the danger of accidents due to in-plant transport and mechanical handling equipment is high.

Quality testing does not give rise to any special safety problems. However, performance testing requires special precautions since the tests are often carried out on semi-finished or uninsulated appliances. During electrical testing, all live components, conductors, terminals and measuring instruments should be protected to prevent accidental contact. The workplace should be screened off, entrance of unauthorized persons prohibited and warning notices posted. In electrical testing areas, the provision of emergency switches is particularly advisable, and the switches should be in a prominent position so that in an emergency all equipment can be immediately de-energized.

For testing appliances that emit x rays or contain radioactive substances, there are radiation protection regulations. A competent supervisor should be made responsible for observance of the regulations.

There are special risks in the use of compressed gases, welding equipment, lasers, impregnation plant, spray-painting equipment, annealing and tempering ovens and high-voltage electrical installations.

During all repair and maintenance activities, adequate lockout/tagout programmes are essential.

Health Hazards

Occupational diseases associated with the manufacture of domestic electrical equipment are relatively low in number and not normally considered to be severe. Such problems that do exist are typified by:

• the development of skin conditions due to the use of solvents, cutting oils, hardeners used with epoxy resin and polychlorinated biphenyls (PCBs)
• the onset of silicosis due to the inhalation of silica in sandblasting (although sand is being increasingly replaced by less toxic blasting agents such as corundum, steel grit or shot)
• health problems due to inhalation of solvent vapours in painting and degreasing, and lead poisoning from use of lead pigments, enamels, etc.
• varying levels of noise produced during the processes.

Wherever possible, highly toxic solvents and chlorinated compounds should be replaced by less dangerous substances; under no circumstances should benzene or carbon tetrachloride be employed as solvents. Lead poisoning may be overcome by substitution of safer materials or techniques and the strict application of safe working procedures, personal hygiene and medical supervision. Where there is a danger of exposure to hazardous concentrations of atmospheric contaminants, the workplace air should be regularly monitored, and appropriate measures such as the installation of an exhaust system taken where necessary. The noise hazard may be reduced by enclosure of noise sources, the use of sound-absorbent materials in workrooms or the use of personal hearing protection.

Safety engineers and industrial physicians should be called upon at the design and planning stage of new plants or operations, and the hazards of processes or machines should be eliminated before processes are started up. This should be followed up by regular inspection of machines, tools, plant, transport equipment, firefighting appliances, workshops and test areas and so on.

Worker participation in the safety effort is essential, and supervisors should ensure that personal protective equipment is available and worn where necessary. Particular attention should be paid to the safety training of new workers, since these account for a relatively high proportion of accidents.

Workers should receive a pre-placement medical examination and, where there is the possibility of hazardous exposure, periodic examination as necessary.

Many processes in the production of individual components will involve the rejection of waste material (e.g., “swarf” from sheet or bar metal), and the disposal of such materials must be in accordance with safety requirements. Furthermore, if such process waste cannot be returned to the producer or manufacturer for recycling, then its subsequent disposal must be by approved processes in order to avoid environmental pollution.

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