Thermal work limit

Thermal work limit (TWL) is an index defined as the maximum sustainable metabolic rate that well-hydrated, acclimatized individuals can maintain in a specific thermal environment within a safe deep body core temperature (< 38.2 °C or 100.8 °F) and sweat rate (< 1.2 kg or 2.6 lb per hour).

The index has been introduced into the United Arab Emirates[2] and Australia, resulting in a substantial fall in the incidence of heat illness in the latter.

[3] The idea of a thermal work limit (TWL) was developed by Graham Bates and Derrick Brake in 1997.

[4] TWL and its management protocols have been introduced into several industrial operations where workers are subject to thermal stress.

[5] The thermal work limit index calculates the maximum metabolic rate, in watts of metabolic heat per square meter of body surface area, that can be continuously expended in a particular thermal environment in order to keep the body within safe physiological limits.