Protect your workers from summer heat stress

With temperatures on the rise, employers must have plans in place to help keep workers safe. Employers have an obligation to protect their workers from heat related illness under work health and safety laws.

Heat stress is the total heat load on the body from sources including:

• ambient air temperature
• radiant heat from other sources (e.g. vehicles, equipment and hot-work processes)
• air movement
• relative humidity
• individual task requirements
• metabolic heat produced by the body because of physical activity.

Working in hot or humid environments can cause heat-related illness and in some cases this can be fatal. There is no recommended temperature limit at which work should cease as setting a safe or unsafe limit simply based on ambient air temperature is not appropriate due to the many variables associated with the onset of heat stress.

The risk is also not just related to temperature. There is a combination of factors that contribute to heat-related problems at work, including:

• exposure to direct sunlight, especially during the hottest part of the day
• exposure to reflected heat from construction materials, polished aluminium and glass
• strenuous tasks or work for sustained long periods
• exposure to additional heat from machinery
• inadequate cooling off, rest periods or insufficient water consumption
• climatic conditions (low air movement, high humidity, high temperature)
• clothing and personal protective equipment that reduces heat loss from the body
• workers not being used to carrying out physical work in hot conditions
• poor diet, vomiting, diarrhoea or alcohol and caffeine consumption
• fatigue related to inadequate or irregular sleep patterns.

A safe system of work should include an assessment of both the environmental conditions at the workplace and the physical well-being of workers, as well as ongoing monitoring and supervision in hot conditions, especially during very hot and humid weather.

The risk and severity of heat related illness will vary widely among workers, even under identical heat stress conditions.

You can prevent heat stress by:

• modifying the work environment:
  • Reduce radiant heat by insulating hot surfaces, clad or cover sources of radiant heat, and use radiant heat shields, or barriers.
  • Increase air movement by installing exhaust or extraction fans to remove hot air, opening doors and windows, installing fans and artificial cooling such as evaporative coolers, air conditioning, vortex tubes, or chillers.
• modifying the way work is carried out:
  • Use mechanical aids such as cranes, forklifts and earthmoving plant to reduce the workload, conduct work at ground level to minimise climbing, and do the work indoors or in a shaded area.
  • Provide rest areas/refuges as near to the work area as possible for workers to escape the heat by. You can use shelters from gazebos, insulated structures, or airconditioned cabins.
  • Use administrative controls could include scheduling of work, rest intervals, fluid replacement and buddy systems.
  • Provide personal protective equipment. Options include wearing a hat, vented eyewear, and specialised cooled or conditioned personal protective clothing.

To assist businesses meet their obligations, Workplace Health and Safety Queensland has a Heat stress (basic) calculator and guidance on managing the risk of heat stress, including the Managing the work environment and facilities Code of Practice 2021 (PDF, 0.57 MB).