The effects of high temperatures in the workplace

High temperatures in the workplace reduce worker morale and productivity, and increase absenteeism and mistakes. In a study performed by ASHVE (now ASHRAE) it was proven that a typical manufacturing plant loses 1% efficiency per man-hour for every degree the temperature rises above 80F (27C).

Extremely high temperatures can also lead to heat exhaustion, heat stroke and eventual collapse.

The causes of high temperatures in the workplace

Operations involving high air temperatures. Radiant heat sources, high humidity, direct physical contact with hot objects, or strenuous physical activities can induce heat stress in workers. Such places include: iron, steel and nonferrous foundries, bakeries, commercial kitchens, laundries, food canneries, chemical plants, mining sites, etc.

High ambient air temperature. Many industrial buildings, factories, warehouses, workshops, etc. suffer from poor ventilation. Hot air is trapped inside, leading to high temperatures, especially during the summer months.

Solar gain. During summer, at midday in the United Kingdom, the sun’s energy is equivalent to 1000w per square metre. Poorly insulated roof spaces quickly heat up to in excess of 140F (60C). This in turn heats the structure and air below.

Outdoor operations performed in hot weather. Such as construction, refining, asbestos removal, and hazardous waste site activities, especially those that require workers to wear heavy protective clothing.

High occupancy buildings. Such as exhibition halls, arenas, tents, marquees, sports halls and gymnasiums, heat up rapidly because each occupant produces heat.

The effects of high temperatures on the human body

Heat Fatigue. The signs and symptoms of heat fatigue include impaired performance of skilled sensorimotor, mental, or vigilance jobs.

There is no treatment for heat fatigue except to remove the heat stress before a more serious heat-related condition develops.

Heat Exhaustion. The signs and symptoms of heat exhaustion are headache, nausea, vertigo, weakness, thirst, and giddiness. Fortunately, heat exhaustion responds readily to prompt treatment.

Workers should be removed from the hot environment and given fluids. They should also take adequate rest.

Heat Stroke. Occurs when the body's system of temperature regulation fails and body temperature rises to critical levels. This condition is caused by a combination of highly variable factors, and its occurrence is difficult to predict.

The worker should be placed in a shady area and outer clothing removed. The worker's skin should be wetted and air movement around the worker increased to improve evaporative cooling. Fluids should be replaced as soon as possible.

Protecting workers from the effects of high temperatures

Inexpensive, portable fans produce air movement which evaporates perspiration, cooling the body. Fans installed in the roof will stop hot air gathering. Fans installed in the walls can supply fresh cooler air from outside.

If more cooling is needed evaporative coolers, or spot coolers provide cool air, albeit at a higher cost.