What is the exposure limit value for thermal stress?

The exposure limit value for thermal stress varies depending on the specific situation and the individual's tolerance to heat. In general, it is recommended to limit exposure to high temperatures and take breaks in a cooler environment to prevent heat-related illnesses. The Occupational Safety and Health Administration (OSHA) recommends a heat stress threshold limit value (TLV) of 86°F (30°C) for moderate work and 77°F (25°C) for heavy work. Employers should also provide adequate hydration, rest breaks, and access to shade or cooling stations to help prevent heat-related illnesses.

The exposure limit value for thermal stress, as defined by the American Conference of Governmental Industrial Hygienists (ACGIH), is:

Threshold Limit Value (TLV): 86°F wet bulb globe temperature (WBGT) for healthy adults performing moderate work (i.e., metabolic rate of 300 to 500 kcal/hr) for 8 hours per day.

The WBGT index takes into account the combined effects of temperature, humidity, radiant heat, and wind speed on the human body's heat exchange.

It is important to note that this exposure limit value is applicable to healthy adults performing moderate work. For individuals with heat-related health conditions or those performing strenuous work, lower exposure limits may be necessary to prevent heat stress.