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Managing the risks of working in heat

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This Guide provides practical guidance for a person conducting a business or undertaking (PCBU) on how to manage the risks associated with working in heat and information on what to do if a worker begins to suffer from a heat-related illness.

This Guide addresses heat that poses a direct risk to a worker’s health and safety, such as heat which may cause heat-related illness. For information on thermal comfort – that is, whether a worker is comfortable at a particular temperature – see the Code of Practice: Managing the Work Environment and Facilities.


What are some common effects of working in heat?

Working in heat can be hazardous and can cause harm to workers. The human body needs to maintain a body temperature of approximately 37 degrees Celsius.
If the body has to work too hard to keep cool or starts to overheat a worker begins to suffer from heat-related illness.

This is a general term to describe a range of progressive heat related conditions including fainting, heat rash, heat cramps, heat exhaustion, and heat stroke.

Some other common effects of working in heat include:

  • Heat rash. Skin can become irritated and cause discomfort when working in heat.
  • Heat cramps. Muscles can cramp as a result of heavy sweating without replacing salt and electrolytes.
  • Fainting. Can occur when workers stand or rise from a sitting position.
  • Dehydration. Increased sweating can lead to dehydration if workers aren’t drinking enough water.
  • Heat exhaustion. Occurs when the body is working too hard to stay cool.
  • Heat stroke. Occurs when the body can no longer cool itself. This can be fatal.
  • Burns. Can occur if a worker comes into contact with hot surfaces or tools.
  • Slips. A worker will sweat more in hot conditions which can increase the risk of slips – for example, a worker might slip when using sharp tools if their hands are damp.
  • Reduced concentration. When working in heat it is more difficult to concentrate and a worker may become confused. This means workers may be more likely to make mistakes, such as forgetting to guard machinery.
  • Increased chemical uptake into the body. Heat can cause the body to absorb chemicals differently and can increase the side effects of some medications.


How can you manage risks?

The following steps should be used, so far as is reasonably practicable, to ensure that workers and other people are not exposed to harm from working in heat. More information on the risk management process is in the Code of Practice: How to manage work health and safety risks.

1. Identify the hazard

Heat is a hazard in many Australian workplaces, whether work is performed indoors or outdoors. To find out if it is a hazard in your workplace, consider:

  • air temperature
  • air flow
  • humidity
  • radiant heat sources
  • work requirements, and
  • the workplace itself

To help you identify hazards in your workplace you should talk to workers, including any health and safety representatives, and other duty holders. You can also talk to businesses similar to yours and find out whether heat is a hazard in that workplace, or to review near misses, incidents and injury records. This can help you identify risks in your workplace. The checklist at Appendix 2 – risk management checklist can be used to record identified hazards.

2. Assess the risk

A risk assessment can help you determine:

  • how severe the risk is
  • whether existing control measures are effective
  • what action you should take to control the risk, and
  • how urgently you need to take action.

To assess the risk you should consider:

  • what is the impact of the hazard, and
  • how likely is the hazard to cause harm.

How hot a worker feels will be different in every situation, depending on the individual worker, the work they are doing and the environment in which they are working.

The work

  • Where is the work being done? Working near heat sources (for example, hot plant or hot surfaces) or in the sun increases exposure to heat.
  • Is the work physically demanding? How long will the worker be doing physically demanding work? Physical effort increases the risk of heat-related illness, even in moderate conditions.
  • How long will the worker be exposed to heat? When and where can they take breaks? Extended exposure to heat makes it harder for the body to stay cool.
  • Could anything prevent a worker from pacing their work? For example, pieceworkers or workers with performance-based salaries may not want to reduce their work rate in hot conditions.
  • When is work being done? For example, working in a roof cavity or outside is most hazardous during the hottest parts of the day and year.
  • Is the work complex or difficult? Concentration may be affected by heat.

The worker

  • What is the worker’s capability? Are they trained, qualified and competent for the work they are doing? An apprentice may take longer to do a task or might not know how to work safely, and their supervisor might also be at increased risk if he or she is exposed to heat for a longer time.
  • Is the worker physically fit and are they acclimatised to the current environment?
  • Are workers required to wear clothing such as personal protective equipment (PPE), standard dress or a uniform? Clothing that impairs the evaporation of sweat increases the risk of heat-related illness.
  • Keeping in mind your obligations under other legislation including privacy and discrimination laws, consider whether a worker has disclosed anything which indicates they are susceptible to heat-related illness. For example, is the worker:
    • A previous sufferer of heat-related illness?
    • Pregnant?
    • At risk of dehydration or electrolyte depletion for example they have diarrhea, vomiting, or are on a fluid-restricted diet?
    • Younger (aged 25 or less) or older (aged 55 or more)?
    • Returning to work after an absence, such as a fly in fly out worker, or someone
      returning to work after an incident?

Note on acclimatisation

Acclimatisation means that the body is starting to adapt to heat. An acclimatised worker may begin to sweat more efficiently and can more easily maintain a normal body temperature. Remember, a person’s body can only adapt so much and this is not a reliable control. If you plan to introduce an acclimatisation program to manage the risks associated with working in heat in your business, consult a professional like an occupational hygienist. Workers who are not acclimatised, or are returning to work after an absence of a week or more, are at a higher risk of experiencing a heat-related illness.

The working environment

  • What is the air temperature? Work being done outside or in a roof cavity will be hotter during the day and in summer.
  • What is the radiant temperature? Radiant temperatures may be high when working in the sun such as on a concrete or metal roof, or near hot machinery or processes, such as in a furnace, kitchen or manufacturing workshop.
  • Is there air movement or wind? Confined spaces or poorly ventilated spaces have minimal air movement making them hotter.
  • Is it humid? Humidity makes it more difficult for a person to cool down.
  • Is there access to cool drinking water? Dehydration can occur if a worker isn’t taking in enough water.
  • Is the work space well ventilated or air-conditioned or are there air-conditioned break rooms?
  • Are workers working alone? A worker may not be able to seek help in an emergency.
  • Is there quick access to support services such as first aiders and emergency services? Heat-related illness can be fatal if left untreated.
  • Is there an emergency plan? If a worker collapses in a confined space, for example, an emergency plan can help get them out and into treatment without delay.
  • Can the worker get to and from work safely? Exposure while travelling can make workers more vulnerable to heat-related illness.
  • Is there a heatwave? Hot days and nights can contribute to worker fatigue.

Note on useful resources

Workplace Health and Safety Queensland has published a Heat Stress basic calculator that may assist you in assessing the risk of working in heat. The Bureau of Meteorology (BOM) is also useful source of up to date information, particularly if your workers will be working outdoors or somewhere where environmental conditions can affect temperature and humidity. BOM’s Heatwave Service for Australia forecasts the location and severity of heatwaves and information on climate zones of Australia, which can help you identify the likelihood of high temperatures and high humidity. BOM also publishes a range of local forecasts and current observations. You can use simple indices such as apparent temperature, which is calculated using ambient temperature and relative humidity, to help you estimate how hot conditions feel to your workers.

If you assess that the risk to your workers associated with working in heat are too high to be
controlled by taking steps like the examples listed in the following section, you could engage
an occupational hygienist to perform a professional risk assessment and devise a
management plan for your business.

3. Control the risk

You must do everything that is reasonably practicable to eliminate the risks associated with working in heat. This may include cancelling certain work tasks, rescheduling tasks to cooler parts of the day or waiting for hot conditions to pass. If you cannot eliminate the risk, you must minimise it as much as reasonably practicable. Remember, heat that represents a hazard to workers may be generated by more than just weather conditions. You may find a combination of controls to be the most effective. Below are some examples of ways you could manage the risks associated with working in heat:

The work

  • Use automated equipment or processes to access hot locations. For example, use a drone to inspect a fire ground.
  • Where possible, have workers do the work elsewhere. Prefabricate materials in air conditioned factories.
  • Install automated or remote-controlled machinery so that workers don’t have to do physically demanding work by hand.
  • Use plant or other equipment to reduce manual labour. Use a crane or forklift to lift heavy objects, or use earthmoving plant for digging.
  • Organise work to minimise physically demanding tasks, for example conduct work at ground level to minimise climbing up and down stairs or ladders.
  • Schedule heavy or strenuous work for cooler times of the day or year.
  • Modify targets and work rates to make the work easier and reduce physical exertion.
  • Modify uniforms or required dress codes so workers can wear cooler, more breathable clothing.
  • Ensure workers are not working alone, or if they must work alone, monitor them and make sure that they can easily call for help.
  • Establish work-rest schedules.

The worker

  • Encourage workers to pace themselves.
  • Monitor and supervise workers.
  • Ensure workers and supervisors are trained to:
    • identify and report hazards associated with heat and heat-related illness
    • understand how to prevent heat-related illness
    • recognise symptoms and signs of heat-related illness in themselves and others
    • call for assistance if necessary
    • identify and use appropriate first aid procedures
    • look out for each other’s wellbeing
    • modify work intensity and take more regular breaks when working in heat
    • drink sufficient water to stay hydrated
    • recognise the dangers of diuretic drinks
    • be aware of individual risk factors
    • understand acclimatisation
    • recognise the potential dangers associated with the use of alcohol and/or drugs when working in heat, and
    • use appropriate PPE correctly.

The working environment

  • Install artificial cooling such as air-conditioning.
  • Insulate buildings and clad sources of radiant heat.
  • Make sure your workspace has good air flow. Install fans or generate air movement for example via windows and vents, particularly in humid conditions.
  • Remove heated air or steam from hot processes using local exhaust ventilation.
  • Provide air-conditioned, shaded or cool break areas as close as possible to the work site.
  • Isolate hot machinery or surfaces by using shields, barriers and guards for example around a furnace.
  • Insulate or enclose hot processes, surfaces or plant.
  • Reduce radiant heat for example by allowing plant to cool down before use.
  • Provide shade to reduce radiant heat from the sun.
  • Provide accessible cool drinking water or when necessary electrolyte solutions.
  • Provide information such as warning signs at the workplace to reinforce training.

For information on how you can manage the risks of working in the sun see Safe Work Australia’s Guide on exposure to solar ultraviolet radiation.

Note on hydration

When working in heat, dehydration is a major risk. Dark or reduced urine output can indicate dehydration. You can manage the risk of dehydration by providing accessible cool drinking water and encouraging workers to stay hydrated. Water is the best way to keep hydrated. Remember that thirst is satisfied before fluid loss is replaced.
Hyponatraemia is a rare condition where a person’s blood sodium levels become dangerously low. Salt tablets are not recommended.

Note on further resources

For more information on controlling the risk see How to determine what is reasonably practicable to meet a health and safety duty, and the Interpretive guideline – model Work Health and Safety Act – the meaning of ‘reasonably practicable’. The Code of Practice: How to manage work health and safety risks provides information on risk management and the hierarchy of risk control.

4. Review the control measures

You must review control measures to ensure that they are working as planned and that they do not introduce new uncontrolled risks. For example, removing PPE to cool a worker down may introduce new hazards such as exposure to chemicals or solar ultraviolet radiation.

Article and Photo by: Tara of Australasian Mine Safety Journal

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