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Hot and cold environments

People working in extreme heat or cold must be able to work without a risk to their health and safety, so far as is reasonably practicable.

Safety vs comfort

It’s important to distinguish between a condition that threatens health and safety, and a feeling of discomfort. The risk to the health of workers increases as conditions move further away from those generally accepted as comfortable.

Factors to consider

Both environmental and personal factors should be considered when assessing the risk to workers’ health from working in a very hot or cold environment.

  • Environmental factors include air temperature, the level of humidity, air movement and radiant heat.
  • Personal factors can include age, health condition, the level of physical activity, the use of some prescription medication, pregnancy and breastfeeding, the amount and type of clothing worn, and duration of exposure.

Ideal temperature ranges

Work should be carried out in an environment where a temperature range:

  • is comfortable for workers
  • suits the work they carry out.

Air temperatures that are too high or too low can contribute to fatigue and heat or cold-related illnesses.

Thermal comfort is affected by many factors, including:

  • air temperature
  • air movement
  • floor temperature
  • humidity
  • clothing
  • the amount of physical exertion
  • average temperature of the surroundings
  • sun penetration.

Optimum comfort for sedentary work is between 20 and 26 degrees Celsius, depending on the time of year and clothing worn. Workers involved in physical exertion usually prefer a lower temperature range.

How you maintain a comfortable temperature will depend on the working environment and the weather, and could include:

  • air-conditioning, fans
  • controlling air flow and the source of drafts
  • open windows
  • building insulation
  • the layout of workstations
  • controlling the direct sunlight into the space.

Health risks of heat and humidity

Heat-related illness can arise from working in high air temperatures or being exposed to high thermal radiation or high levels of humidity, such as those in foundries, commercial kitchens and laundries.

Symptoms of heat exhaustion or heat stroke include:

  • dizziness
  • fatigue
  • headache
  • nausea sometimes with vomiting
  • breathlessness
  • clammy or hot skin
  • difficulty remaining alert
  • absence of sweat.

You should seek immediate medical attention if a worker experiences any of these symptoms.

Hot environments

If it’s not possible to completely eliminate exposure to extreme heat, you must reduce the risk of heat-related illness so far as is reasonably practicable. Examples include:

  • increase air movement using fans
  • install air-conditioners or evaporative coolers to lower air temperature
  • isolate workers from indoor heat sources, for example by insulating plant, pipes and walls
  • remove heated air or steam from hot processes using local exhaust ventilation
  • use mechanical aids to help workers perform manual tasks (reducing their physical exertion)
  • alter work schedules so that work is done at cooler times.

The following control measures should also be considered but are least effective if used on their own:

  • slow down the pace of work if possible
  • provide a supply of cool drinking water
  • provide a cool, well-ventilated area where workers can take rest breaks
  • provide opportunities for workers who aren’t used to working in hot conditions to acclimatise; for example, job rotation and regular rest breaks
  • ensure light clothing is worn to allow free movement of air and sweat evaporation
  • make sure workers are trained about the hazards of working in hot conditions, and can recognise and act on the symptoms of heat-related illness in themselves and others.

Health risks of cold

Hypothermia arises when someone gets an abnormally low body temperature from being exposed to cold environments, or getting wet from rain or perspiration.

Symptoms of hypothermia include:

  • shivering you can’t control
  • numb hands or feet, lack of fine motor co-ordination (having trouble with buttons or zips)
  • slurred speech
  • dazed or fuzzy thinking
  • irrational behaviour, such as wanting to take off clothing.

You should seek immediate medical attention if a worker experiences any of these symptoms.

Even mild symptoms can create a hazard. Cold muscles are more prone to strains and sprains, and lack of mental and physical co-ordination from numb hands can put workers at risk.

Cold environments

If it’s not possible to completely remove eliminate extreme cold, you must reduce the risk of hypothermia so far as is reasonably practicable. Examples include providing:

  • localised heating, for example cab heaters for fork-lift trucks used in cold stores
  • protection from wind and rain, such as a hut or the cabin of a vehicle.

The following control measures should also be considered but are least effective if used on their own:

  • provide protection through warm and (if necessary) waterproof clothing
  • provide opportunities for workers who aren’t used to working in cold conditions to acclimatise; for example, job rotation and regular rest breaks
  • make sure workers are trained about the hazards of working in cold conditions, and can recognise and act on the symptoms of hypothermia in themselves and others.

Resources

WorkSafe Tasmania resources

Sun exposure and UV radiation

Other resources

Guide for managing the risks of working in heat: Safe Work Australia (external link)

Heatwave assessments: Bureau of Meteorology (external link)

Skin cancer and outdoor work: A health and safety guide: Cancer Council Australia (external link)

Work outdoors? Use UV protection everyday: Cancer Council Australia (external link)

Working in heat: Physically demanding work (video): Safe Work Australia (external link)

Updated: 5th December 2019