ABSTRACT

The human body generates heat: the amount of heat production fluctuates with the intensity of the physical work done. The body must dissipate excess heat to its surroundings: this is easy in a cold climate but difficult in a hot environment. The physiological requirement of keeping the body core temperature the same establishes the need for proper human engineering of the environmental climate. Light-coloured clothing minimizes heat gain by radiation from the sun on a sunny day, while dark-coloured clothes worn outside absorb the sun's radiated heat. To conserve heat, the body lowers the temperature of the skin to reduce the temperature difference against the outside. A convenient way to assess the existent climate is to combine a set of special measurement instruments in one device, which weighs the separate measurement results according to their effects on the human body and from there derives a single index.