A composite of mean radiant temperature and air temperature; also defined as the mean temperature of the environment effective in controlling the rate of sensible heat loss from a black body in still air when the surface temperature and size of the black body are comparable to those of the human body. Where the enclosure surface (mean radiant temperature) and air temperatures are equal, this temperature is also the British equivalent temperature; when not equal, the British equivalent temperature is that temperature at which a body with an 80 degrees F (26.7 degrees C) surface temperature will lose sensible heat at the same rate as in the given environment.