Thermal Comfort Assessment

Cold stress results when the body is not able to warm itself. Cold stress may result in tissue damage and may result in death. Factors that contribute to cold stress include cold air temperatures, high air movement, dampness of the air, and contact with cold water surfaces. Common cold induced problems include:

  • hypothermia, a serious health condition that occurs when the body heat is lost faster than it can be replaced. The exposed worker may begin to shiver and stomp their feet in order to generate heat. they may lose coordination, have slurred speech, and fumble with items in the hand. As a result the skin may become pale and cold. Anyone working in a cold environment may be at risk for cold stress.
  • Frostbite, occurs when the skin actually freezes and loses water. IN some severe cases, this may result in amputation of the frostbitten area. Frostbite generally affects the extremities, especially the feet and hands. These areas will be cold, tingling, stinging or aching which is followed by numbness. 

Heat stress is induced when employees are involved in operations with high temperatures, radiant heat sources, high humidity, direct contact with hot objects or strenuous physical activities. Such activities are typically found in iron and steel foundries, nonferrous foundries, brick firing and ceramic plants, glass products facilities, rubber products factories, electrical utilities (e.g., boiler rooms), bakeries, confectioneries, commercial kitchens, laundries, food canneries, chemical plants, mining sites, smelters, and steam tunnels.

Other activities that may expose employees to heat stress include outdoor operations that are conducted in hot weather (e.g., construction, refining, asbestos removal, and hazardous waste site activities, especially that that require workers to wear semipermeable or impermeable protective clothing. Heat disorders include:

  • Heat stroke which occurs when the body's system of temperature regulation fails and body temperature rises to critical levels.
  • Heat exhaustion which has signs and symptoms of headache, nausea, vertigo, weakness, thirst, and giddiness.
  • Heat cramps, usually caused by performing hard physical labour in hot environments.
  • Heat collapse / fainting whereby the brain does not receive enough oxygen because of blood pols n the extremities.
  • Heat rashes manifested as red papules and usually appears in areas where the clothing is restrictive.
  • Heat fatigue which predisposes an employee to heat fatigue.

Cold stress and heat stress measurements are conducted by means of a WBGT meter.