IMPACT OF METABOLIC-RATE ON HUMAN RESPONSE TO AIR MOVEMENTS DURING WORK IN COOL ENVIRONMENTS

The impact of metabolic rate on human sensitivity to draught was studi ed in a series of laboratory experiments. Ten male subjects were expos ed to mean air velocities increased step-by-step ranging from 0.05 m . s(-1) to 0.40 m . s(-1) at air temperatures of 11, 14, 17 and 20 degr ees C, while performing standing physical work at two different activi ty levels (104 W . m(-2) and 129 W . m(-2)). The subjects were asked w hether they could feel an air movement, whether it was uncomfortable a nd where it was felt. The neck was identified as the most draught sens itive area, and draught was most often felt at the head region compris ing neck, face and upper back. At the uncovered regions of the hands a nd face an influence of air temperature on local draught ratings was s een whereas the percentage of dissatisfied due to draught at the head region did not depend on the air temperature. The results showed that working at a high activity level resulted in fewer dissatisfied due to draught, as compared to a low activity level. It was concluded that t he metabolic rate, equivalent to the internal heat production, signifi cantly influenced human response to air movements for standing activit y in a cool environment. Relevance to industry Draught, defined as an unwanted, local cooling of the skin caused by air movements, is a comm on cause of complaints among employees working in cool or cold industr ial spaces. No studies are available that investigate draught sensitiv ity for persons performing manual work. In this paper, the effect of w orkload (metabolic rate) on human sensitivity to draught is studied wi th subjects working in a cool environment.