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How Hot Is Too Hot?


Have you ever wondered why there is no specific legislation covering maximum workplace temperatures? The simple answer is that no one temperature would sufficiently cover all workplaces. For example, some industries such as foundries and bakeries, through their work processes, naturally generate hot temperatures. However, with proper heat stress programs in place, work can be safely carried out at these high temperatures. Governmental bodies recommend the employers follow the guidelines as set out by the American Conference of Governmental Industrial Hygienists (ACGIH). The goal of these guidelines is to safeguard the worker’s core body temperature, so it does not exceed 38.0°C as if the core body temperature rises above 38.0°C heat stress starts to occur.

The general duty clause in legislation, requires that employers take every precaution reasonable in the circumstances to ensure the health and safety of the worker. In order to do so, the employer is responsible identifying all hazards and taking all reasonable steps in controlling the hazard. In the case of heat stress, programs must be developed and implemented to either control or mitigate the risks.

Effective heat stress programs encompass the following:

  • The development of policies and procedures including the roles and responsibilities of all workplace parties.

  • Decide on a method for measuring and monitoring workplace conditions for temperature and humidity e.g. WBGT, humidex, self-regulation, thermal hygrometer (humidity), radiant heat, air movement Note: some tools can be complex, and interpretation requires expertise.

  • Elimination, where possible.

  • Acclimatization - gradual exposure to build up tolerance Note: the ability to become acclimatized varies from worker to worker.

  • Engineering Controls – air conditioning, fans, ventilation, etc.

  • Administrative Controls regarding work practices – increasing breaks, shorter exposure times, reduce physical job demands, providing cooling areas, job rotation, providing drinking water, buddy system.

  • Personal Control Measures e.g. workers on medication consulting with their physician for possible increased intolerance to heat and humidity, workers monitoring themselves.

  • Protective Clothing and PPE – as a last resort.

  • Outlining Emergency Measures – includes training in the recognition of heat stress and the appropriate response to heat stress related illnesses (first aid).

  • Investigation procedure for all heat stress related incidents.

  • Evaluation of the program – at least yearly to ensure the program is still effective.

As previously mentioned, heat can affect each employee differently, therefore, employers must take in account the following factors:

  • Weight – the size of the person may affect their body’s ability to regulate temperature.

  • Physical condition – poor physical fitness increase the level of risk.

  • Previous Heat Illness – previous illnesses make you more susceptible.

  • Age – as the body ages, sweat glands become less efficient.

  • Heart Disease and High Blood Pressure – this can lead to increased stress on the heart.

  • Recent Illness – can increase the risk of dehydration.

  • Medication, Alcohol Consumption – can lead to intolerance and dehydration.

Overall, the key to preventing heat stress is early recognition of what are the signs and acting on these signs accordingly. An effective heat stress program will not only identify what is heat stress but will have proactive measures in place to help combat heat stress and thus keeping employees safe.

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