Heat, inadequate lighting and noise not only cause discomfort but affect safety, health and work efficiency. Although you can feel, see and hear these conditions, they are frequently neglected.
The work area temperature, the amount and quality of light and the levels of noise are common working conditions factors found in all workplaces. These conditions can affect safety and health in factory premises where mechanisation and automation have brought about changes. If inappropriate or excessive, these factors can strongly influence how a task is performed and affect productivity.
These are important safety and health factors. For example, hot, humid conditions add to fatigue and cause potential health risks, and noise makes hearing of warnings impossible, causes misunderstanding and can lead to permanent loss of hearing.
Techniques to regulate temperature, provide adequate lighting and reduce noise are constantly being developed. Effective guide-lines are made to protect workers from health risks.
The climate is the condition of the atmosphere surrounding us. It can mean the general conditions in a geographical area or, in a narrow sense the local atmospheric conditions in a specific workplace.
In the hot season, we feel very uncomfortable and our efficiency of work drops. With higher living standards and technology, we are sometimes able to control the climate in the space we live or work in. In factories or in outdoor work, however, we are often exposed to intolerable heat and therefore need to take measures to reduce the harmful effects of heat.
We can reduce the heat by installing air-conditioning. This however is costly and cannot be universally applied It is also important to have an adequate exchange of fresh air.
Body heat balance
Physical work produces heat in our bodies. To maintain normal body temperature, the body must get rid of excess heat. Body heat balance must be maintained. Body heat balance is simply a balance between the body’s heat gain and heat loss. Our body has the ability to maintain a normal body temperature by losing heat. Outside the comfort zone, this ability can no longer ensure heat balance. The discomfort you feel in a hot zone is a valuable warning sign.
The three main sources of heat
Air temperature, wind and humidity.
Radiation from the sun, machines and processes.
The three ways by which the body loses heat are
, which is conveying heat from our skin to air; heat loss is greater when wind speed is high. Conversely, we absorb heat when the air temperature is higher than skin temperature.
, when the skin radiates heat to cooler surfaces around. If, however, the skin is exposed to heated surfaces, we absorb heat. The latter happens when we are in sunlight or near a furnace, heated tank, etc.,
, when perspiration, namely water, evaporates from the skin, it takes away heat from us. Naturally, this heat loss by evaporation is facilitated by wind and is hampered by high humidity.
Therefore, in a hot climate there are several ways in which the body absorbs heat, but it can effectively lose heat only through perspiration.
In order to maintain body heat balance these factors must be within a limited range. This range varies from person to person, with season, clothing, job stress and culture. The comfort zone accepted by most people ranges from 20° to 25°C, with relative humidity of about 30 to 70 per cent, if the physical workload is light and there is no radiant heat.
As the physical workload increases, cooler air temperature is needed to maintain comfort Because the working muscles generate heat during physically heavy work, comfort is only maintained below 20°C. Increased wind speed is a positive comfort factor when air temperature is at or above the upper limit of the comfort zone. Air velocity of 0.1 to 0.3 metre per second is fairly typical of the comfort zone for light work.
When the local climate does not permit our body to get rid of excess heat or retain a normal body temperature, we experience real discomfort. Then our ability to work is impaired. In extreme cases we may end up completely exhausted or even incapacitated by ill-health.