Environmental Warmth and Human Comfort

The measurement of body heat production is discussed, and sample rates of heat production for various forms of activity are quoted. The physiological mechanisms which regulate the rate of heat loss are described. Various scales of warmth which take into account other environmental factors besides air temperature are described and their validity discussed in the light of the results of an extensive study of the thermal comfort of factory workers. The "comfort zone" is defined in terms of these scales of warmth. Reference is made to temperature gradients and to draughts as causes of discomfort. The factors which produce feelings of freshness or of stuffiness are discussed. Attention is drawn to the invigorating effect of variable air movement and of the combination of warm walls and cool air. The requirements for a pleasant and invigorating indoor environment are summarized.