Outdoor Factors

Outdoor operations that are conducted in hot weather, such as construction, refining, asbestos removal, hazardous waste site activities, and emergency response operations, can cause or contribute to heat stress. Other operations conducted in hot weather and direct sun, such as farm work, oil and gas well operations, and landscaping also increase the risk of heat-related illness in exposed workers. Workers who are required to wear semi-permeable or impermeable protective clothing are at a higher risk of heat-related stress and illness. This is due to the extra weight and potential for trapped heat within the garments.

Temperature and humidity

Temperature is not the only factor that workers and employers should take into account when preparing to work outdoors. Although high temperatures can contribute to the heat index, humidity - the measurement of moisture in the air - affects the heat index as well. Because sweating is a primary response to cooling the body, the amount of moisture in the air can inhibit the body's ability to sweat effectively. This is because the perspiration does not cool the body as well when the moisture content in the atmosphere is too saturated to evaporate the moisture that appears on the skin, thus limiting the cooling effect.

To learn more about Heat Stress visit our Heat Stress, Illness & Injury Safety Online Training web page.