Remember to drink and take breaks in hot conditions

When people work in exceptionally hot conditions, there is an increased pressure of work and a greater risk of accidents. The heat can also be harmful to health and reduce productivity. Temperatures of between 21 and 25 °C are considered to be comfortable according the occupational safety and health administration.

High temperatures affect the body in many ways. When the body temperature rises, metabolism increases and there is pressure on the heart when the body tries to cool down by increasing the blood circulation. The muscles’ blood circulation is lowered, however, and their ability to function decreases.

The increased metabolism causes dehydration and a person can sweat up to one litre an hour. Bodily fluids and the saline balance are disturbed if people don’t remember to take sufficient drinks.

In assessing heat conditions, consideration is given to how arduous the work is, clothing and physical factors, that is, the air temperature, heat from radiation, air speed and air moisture. Moreover, everyone experiences and is affected individually by the heat conditions.

Comfortable temperatures between 21 and 25 °C

The Workers’ Safety Administration’s recommendations for air temperature according to pressure of work:

Pressure of work	Recommended temperature
light sedentary work	21–25 °C
other light work	19–23 °C
average work	17–21 °C
arduous work	12–17 °C

If the air temperature in the workplace exceeds 28 °C during a heat wave in spite of technical measures, the employer must limit the time during which employees work in such conditions. The length of a work period may be a maximum of 50 minutes an hour, if the employee carries out light or average work at a mechanical tempo in a temperature of 29–33 °C.

If the temperature exceeds 33 °C during such works, the longest permissible work period is 45 minutes an hour. In such situations, employees should be able to work 10-15 minutes an hour in cooler working premises.

There can also be exposure to heat at lower temperatures if the work is very arduous. Work is carried out in hot conditions in the metal, glass-blowing and ceramics industries, amongst others.

Examples of work places with hot and humid working conditions are laundries, large kitchens, the paper industry and the food industry. There are hot work phases in building, asphalting and insulation works.

Prevention of problems in hot working conditions

• insulation of hot parts, pipes and processes
• cooling of workspaces
• cooling of the workplace
• personal protective equipment.