What is Thermal work limit?

Thermal Work Limit is defined as the limiting sustainable metabolic rate that well-hydrated, acclimatized individuals can maintain in a specific thermal environment, within a safe deep body core temperature and sweat rate. The index is designed for self-paced workers and does not rely on estimation of actual metabolic rates, a process that is difficult and subject to considerable error. The index has been introduced into the United Arab Emirates and Australia, resulting in a substantial and sustained fall in the incidence of heat illness in the latter.