# Limits of Behavioral Efficiency for Workers in Heat Stress

Citation:
Hancock, P.A., & Vercruyssen, M. (1988). Limits of behavioral efficiency for workers in heat stress. International Journal of Industrial Ergonomics, 3, 149-158.

Abstract:
This paper describes three zones which differentiate the limits of human behavioral efficiency in heat stress. They are: (1) a zone of thermal intolerance, (2) a zone which identifies the upper thermal tolerances for unimpaired cognitive and neuromuscular performance, and (3) a zone of thermal equilibration. Description of the boundaries to these zones through concurrent identification of time/intensity specifications and physiological criteria allows their broad application across both traditional industrial industrial conditions and activity in unusual occupational environments (e.g., those requiring enclosed garment useage), where contemporary indices based on physical values of the ambient surround are of restricted applicability. It is suggested that these criteria, based upon performance change, can be used to augment current heat stress standards which are founded upon physiological evidence of impairment.