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| Module 1: Occupational Hygiene - Section 5: Instrumentation |
| OH5.8: Evaluation of Thermal Stress - Introduction |
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| Module 1: Occupational Hygiene - Section 5: Instrumentation |
| OH5.8: Evaluation of Thermal Stress - Introduction |
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Thousands of workers around the country work in conditions which expose them to hot or cold environments. Extremes of temperature affect the amount of work people do and the manner in which they do it. In many workplaces the problem is often high temperatures rather than low temperatures.
The main sources of heat in industry are extremely hot or molten materials (bakeries, foundries, smelters, steel mills) and summer sunshine (construction, agriculture, surface mining).
The human body maintains a fairly constant internal temperature, even though it is being exposed to varying environmental temperatures. This is achieved by maintaining a balance between the amount of heat gained by the body and that released from the body.
When body temperature increases, blood circulates closer to the surface of the skin, and the excess heat is lost to the cooler environment.
When body temperature drops, blood moves to the centre (core) of the body and this cuts down the amount of heat lost. If temperature continues to drop, the body starts shivering to generate heat.
Heat stress is the aggregate of internal and external heat load factors on the body.
Heat strain is the sum of all biochemical, physiological, psychological and pathological adjustments in the person in response to heat stress.
External (thermal environment) factors:
