The heat wave expected to hit New Zealand this week means workers and employers need to be more vigilant about working in heat.

Management of work in extreme temperatures has been a workplace health and safety consideration for many decades already, says WorkSafe’s Head of Health and Technical Services, Catherine Epps. 

“Employers have a legal obligation under the Health and Safety at Work Act 2015 (HSWA) to identify risk in the workplace and mitigate that risk appropriately.

“WorkSafe works with businesses to assist in their risk management. Managing extremes in workplace temperature – both hot and cold - is one of these risks.

“HSWA is not prescriptive so does not specify extreme temperatures at which workers are able to stop work for health and safety reasons.

“Recognising the signs of thermal discomfort or stress and raising concerns is important for both businesses and workers to manage health risks that come from working in an environment – that is too hot or too cold. Workers and businesses need to be aware that there is a link between heat and fatigue, which leads to potential for more fatigue-related accidents,” says Ms Epps.

Safe working temperature is not indicated by an air temperature alone. Factors that contribute to the effect of heat on a worker:

  • Air temperature: how hot or cold the air is
  • Humidity: the moisture content of the air
  • Radiant heat: heat emitted from any hot object or surface
  • Air movement: which may cool the air, or in cold environments may cause a wind chill effect
  • Physical activity: greater activity increases the generation of heat in the body
  • Clothing: can aid or prevent heat transfer

Minimising the risk of harm for extreme workplace temperatures can include isolation and engineering controls such as:

  • Ventilation and air conditioning
  • Shielding
  • modify the process so less heat is needed to carry out task or
  • reduce the heat created in carrying out a process to the lowest possible level

It can also include administrative controls such as:

  • minimise exposure to heat where unnecessary and provide regular and sufficient hydration
  • pre-plan jobs to minimise exposure through quick and efficient work, and do non-essential work at times when heat is lowest
  • rotate jobs and reconsider working hours when practicable
  • provide first aid training to recognise and treat any heat-related disorders
  • provide training to understand the effect of fitness, diet, health and life choices (alcohol) on heat stress and risk
  • reduce the amount of physical work a person has to do and provide adequate rest periods
  • provide suitable and/or protective clothing
  • allow workers to acclimatise
  • provide appropriate medical assessments.