Sensitivity and discomfort associated with overhead thermal radiation.

Abstract

Abstract One hundred ond forty-eight subjects each experienced one of four levels of overhead radiation, up to a maximum ceiling temperature of 45°C. The degree of asymmetry is characterized by the vector radiant temperature (v.r.t.); the four levels were 0, 5, 9 and 14 K. Air and wall temperatures were hold equal to each other, and reduced to compensate for the raised coiling temperatures, so that perceived warmth was constant across the conditions. After 15 min exposure, the subjects rated the environment on seven scales Scales of general evaluation showed a slight improvement with increasing asymmetry. However, a scale which asked whether the hot ceiling caused discomfort showed a stady increase in discomfort with increasing asymmetry. It appears that people are ready to attribute discomfort to unusual aspects of the environment. A maxiinum asymmetry of v.r.t. = 10 K is therefore suggested as a design criterion; this level did not actually increase discomfort, but was noticeable and in pmetice levelsgreater than this are likely to produce complaints.