Recognising individual risk factors for heat stress

Heat stress is a complex issue when it comes to keeping workers safe, healthy and productive.

Maintaining a safe internal core temperature at work (and minimising risks of heat stress), is affected by three main factors:

• task (the type of work being undertaken)
• environmental (the nature of work environment)
• individual (the human body’s ability to tolerate heat).

Individual factors

The ability to tolerate heat will vary significantly between workers due to individual and pre-disposing factors. Individual factors should be considered when assessing risk and identifying suitable controls include (but are not limited to):

Image source: Resources Safety & Health Queensland.

Additionally, the bravado of a team member can lead to workers concealing early signs and symptoms of heat illness, overexposure and over-exertion when performing physical tasks.

Providing workers with adequate information and training on the risks associated with heat stress form an essential component of the risk management process.

Assessing risk

It’s important to remember that, for many workplaces, the level of risk will change throughout the year, especially in the hotter months, throughout the workday or shift as well. This means risk assessments should be undertaken regularly to ensure changes in risk factors are considered and properly managed.

As part of your heat stress identification and assessment, you should conduct a walk-through survey of the workplace and ask your workers about their heat stress issues. Consider the work location's previous history of heat stress issues, including what time of day or year and under what circumstances they occurred.

Using the Workplace Health and Safety Queensland (WHSQ) Heat Stress Calculator

To assist in this process, the Heat Stress (basic) Calculator can be a valuable tool.

This online calculator allows for a basic risk assessment of heat stress without the need for direct measurement of environmental conditions. It considers factors such as acclimatisation, work demands, clothing, sun exposure and air movement to provide an initial qualitative review of potential heat stress situations. This can help identify areas where more detailed assessments or immediate interventions are needed.

Questions to consider during a risk assessment include:

• can the work be done in a cooler environment (for example, scheduling the work for a cooler part of the day)?
• can ventilation be improved?
• have workers been properly trained?
• are workers properly acclimatised to the work and environment?
• can hot surfaces be insulated or covered to reduce radiant heat?
• can shields and barriers be installed to protect workers from heat (for example, portable gazebos to provide shade)?
• can humidity be reduced?
• can a cool rest area be provided?
• how intense and prolonged is the work?
• is cool water provided and easily accessible?
• are workers wearing multiple layers of clothing and/or personal protective equipment (PPE)?

It’s important to maintain and review your controls regularly to ensure they’re working properly, especially where conditions can change frequently.

More information

• How to manage exposure
• Pre-start checklist
• Work health and safety eTools
• Watch the video, heat stress management – you’re doing it wrong by Dr Matt Brearley, Occupational heat stress consultant.