Heat, whether 'seasonal' or part of the 'normal work environment', can be a hazard - working in heat can lead to workers suffering serious illness and can also lead to increased accidents. Here's information on the effects of heat and gives reps an Action Plan on how to tackle the issue at the the workplace.

Page Overview

VTHC Recommendations:

Work related injuries and illnesses due to exposure to heat must be prevented primarily through elimination, modifying the workplace or systems of work. Where these measures do not adequately control the risk, it may be necessary to introduce administrative controls (for example introduction of a work-rest regime).

Action Plan For Safety Representatives:

  1. Talk to your members about heat and its effects on health: also identify if there are any heat problems associated with their work and whether seasonal heat may be a problem. Remember, hear is not just an issue for outdoor workers - there are many situations where workplaces become extremely hot (even hotter than outdoors) due to poor ventilation, lack of air conditioning, and/or big windows. See more information on the problem, below.
  2. Carry out an audit of the workplace to identify heat stress areas.
  3. Negotiate a Heat Agreement or Policy:

    As climate change is making Australian summers hotter than ever before, it is becoming increasingly important not to wait until summer to raise the issue with management and begin the process of negotiating a heat agreement appropriate to your workplace. This should be done at an OHS Committee level, ensuring the input of all affected workers. If there is no OHS Committee, then it can be raised by the HSR directly with management. The agreement should consider both seasonal and work-related heat. It should include at least the following:

    • All new indoor work areas to be temperature-controlled, where practicable, by air-conditioning.
    • Where possible the workers' environment to be maintained in a range between 18° and 23° C (depending on the type of work being done).
    • Temperatures be kept in that range through the use of engineering controls such as:
      • Air conditioning, air circulating fans, provision of good ventilation;
      • Insulating or shielding sources of heat in the workplace;
      • Insulating the roofs and walls of the workplace;
      • reducing heat gain via windows by reflective film or blinds, and by reducing window area, and moving desks and workstations away from windows;
      • Ducting hot exhausts outside the workplace;
      • Mechanising some of the tasks; and
      • Providing air-conditioned work vehicles.
    • A general heat hazard audit carried out to identify and prioritise areas/processes of concern.
    • For outdoor work:
      • Establishment of 'cool' areas, including air-conditioned lunch and first aid room/s;
      • Providing a choice of light protective clothing and hats;
      • Use of air-circulating fans;
      • Use of shade cloths.
    • Administrative controls:
      • Sign posting heat stress areas;
      • Acclimatisation process in heat stress area for new workers and those returning from annual/sick leave, beginning with half regular workload;
      • Changing the rate of work;
      • Modifying the hours of work (in consultation with the union. Check your Enterprise Agreement);
      • Providing lighter, alternative work;
      • Rest breaks (see below);
      • Mechanising some of the work tasks (eg using power tools);
      • allowing staff to dress appropriately for hot weather, e.g. allowing ties, tights or jackets to be removed or shorts to be worn.
    • Personal Protective measures
    • Investigating any incidents of heat stress (use, for example, the Heat incident report form - downloadable here)
    • Providing effective sunburn creams and skin protectors
    • Providing constant supplies of cool drinking water. Workers should drink 100-200ml
      of water at frequent intervals to replace fluid lost through perspiration. Recent research has found that in very hot and humid conditions, it is important that workers are provided with electrolyte rich drinks. (see: the US research Electrolyte Beverage Intake to Promote Hydration and Maintain Kidney Function in Guatemalan Sugarcane Workers Laboring in Hot Conditions, and our summary, here. Also: HSE Manager Talks Heat Stress noting the VTHC does not endorse any particular products) The VTHC recommends that HSRs raise the provision of electrolyte drinks in their consultations with employers. 

Rest - Work breaks

The following is a suggested place to start when negotiating a rest-work regime for inclusion in a Heat Policy.

Duration of paid rest breaks within each hour when the temperature reaches and/or exceeds temperatures shown Temperature
(Degrees Celsius)
15 minutes 30 degrees
30 minutes 32 degrees
45 minutes 34 degrees
60 minutes 36 degrees

For more detailed and complex advice, see the tables on the Canadian Hot Environments - Control Measures.

Ensure the policy is reviewed each year by the OHS Committee.

Summary for the Health and Safety Representative:

  • Talk to your members about heat and its health and safety effects.
  • Carry out an audit of the workplace to identify heat stress areas.
  • Ensure the employer monitors the conditions at the workplace - this includes monitoring the temperatures.
  • Ensure the employer monitors the health and safety of workers.
  • Ensure that all incidents are reported.
  • Negotiate a heat policy appropriate to your workplace through your health and safety committee if you have one - don't wait until summer to raise the issue with management.
  • Ensure that the employer is providing workers with cool water, and if suitable, electrolyte drinks.
  • Ensure that means of reducing/maintaining the temperature are regularly checked (eg air conditioning systems)
  • Review your policy each year.

Download a hierarchy of controls for heat here:

There are no regulations specifying standards for maximum temperatures in the workplace.

However, employers have a duty under the Victorian Occupational Health and Safety Act (2004) to provide and maintain for employees, as far as practicable, a working environment that is safe and without risks to health. This includes providing a safe system of work, information, training, supervision, and where appropriate personal protective equipment. The employer also has the duty to monitor conditions at the workplace - including the temperature. HSRs should raise this with their employer, and initiate discussions on where in the workplace the temperature needs to be monitored.

Importantly, the employer has a duty to identify hazards and implement controls to eliminate or, if this is not reasonably practicable, reduce the risks associated with the hazards. The employer MUST consult with elected ohs reps where these exist, and affected workers on the measures to be implemented to eliminate/reduce the risks. (S 35 of the Act).

Some workers have been able to negotiate agreements (now in either their award or Enterprise Agreement) on this issue.

In addition, the Victorian Compliance Code for Workplace amenities and work environment includes provisions that can be used to protect workers from heat stress. These are things the employers 'needs to do' to comply with Section 21 duties. These provisions (numbered below as per the Code) could be useful in developing policies in your workplace.

  • Clean drinking water needs to be provided for employees at all times (34). Water needs to be: free of charge; supplied so that one drinking point should be provided for every forty employees or part thereof; situation within 30 metres of each employee or within reach of employees who cannot leave their work task. (35)
  • When workplaces are temporary, remote or mobile, and employers are unable to provide drinking points, they need to provide the amenity by ensuring access to public drinking water facilities, bottled water or containers for employees to take with them. Such employees include transport drivers, security personnel, park rangers & gardeners, forestry employees, sale reps or mobile community health workers. (36)
  • Drinking water needs to be clean, safe for consumption, cool and palatable. (37) (For more information on the quality of drinking water, see  the NHMRC Australian Drinking Water Guidelines [38])
  • Drinking water needs to be from outlets that are separate from sanitary and hand washing facilities to avoid contamination and hygienically provided by means of disposable or washable drinking containers or delivered by a drinking fountain so that employees do not share drinking containers. (39)
  • Workplaces that are buildings need to be capable of maintaining a temperature range that is comfortable and suitable to the work. Workplace temperatures that are too high or too low can contribute to fatigue, heat illness and cold-related medical conditions. (122)
  • Optimum comfort for sedentary work is between 20°C and 26°C, depending on the time of the year and clothing worn.  Employees undertaking work requiring physical exertion usually prefer a lower temperature range. (124)
  • The means of maintaining a comfortable temperature will depend on the working environment and the weather and could include any of the following (125):
    • air conditioning
    • fans
    • electric heating
    • open windows
    • building insulation
    • the layout of workstations
    • direct sunlight control
    • controlling airflow and the source of draughts
    • a work and rest regime 

      All heating and cooling facilities need to be serviced regularly and maintained in a safe condition (126)

  • Air movement throughout a workplace is necessary for the health and comfort of employees. Employers need to ensure workplaces that are buildings provide natural ventilation, or mechanical ventilation which complies with AS 1668 The use of ventilation and airconditioning in buildings. In enclosed workplaces, employers need to ensure that comfortable rates of air movements (usually between 0.1m and 0.2m per second) are maintained. (128 - 131)
  • For outdoor employees: Employers need to ensure access to shelter such as shelter sheds, caravans, tents, windbreaks or portable shade canopies (for protection when weather conditions become unsafe) (104 - 106). For detailed advice on protection from the risk is skin cancer see the WorkSafe Guidance Note:  Sun protection for construction and other outdoor workers [pdf]

The National Health and Medical Research Council recommends the introduction of a work-rest regime for acclimatised workers doing different types of work at varying temperature levels measured by Wet Bulb Globe Thermometer.

The UK's OHS regulator, the Health and Safety Executive (HSE), has a section on their website which specifically addresses matters of Temperature , including what the HSE recommends in terms of minimum and maximum temperatures.

In September 2021, the US President Joe Biden announced his administration would introduce the USA’s first ever labour standard aimed at protecting workers from extreme heat, as part of a growing recognition of the dangers posed by warming temperatures caused by climate change. 

The country's OHS regulator, OSHA will prioritise heat-related interventions and work inspections on days when the heat index exceeds 80 degrees (27 degrees Celsius), the administration said. OSHA is already working to complete a programme before next summer that will target industries at higher risk of heat injuries, and to focus more resources on inspections. OSHA's  Heat illness prevention campaign

Measuring Heat

An ordinary dry bulb (DB) thermometer is adequate to measure air temperature when humidity and air movement is not excessive and is often the only practical method to measure temperature.

A wet bulb globe thermometer (WBGT) temperature is calculated using a formula that takes into account air temperature, speed of air movement, radiant heat from hot objects, sunshine and body cooling due to sweat evaporation. Two different methods are used to calculate WBGT in the workplace: one for workplaces with direct sunlight, and the other for workplaces without direct sunlight.

The WBGT index was developed in 1956 by the United States Marine Corps at Parris Island to reduce heat stress injuries in recruits; it has been revised several times. While this is an internationally recognised method widely used for assessing environmental risk factors, it should only be used where a competent, qualified occupational hygienist is carrying out the monitoring.

The Problem

Working in hot conditions can result in a number of adverse health effects - ranging from discomfort to serious illness, which are generally grouped together as heat stress. In extreme circumstances this can be fatal.

A number of factors affect the impact of heat on the body. These are:


  • Air temperature, humidity and air movement
  • Radiant temperature in the workplace
  • Extreme climatic conditions - exacerbated by climate change and at times bushfires

A factor that increases the impact of heat on workers is global warming caused by climate change. It is a fact that over the past century, global temperatures have risen. The effects of these for Australia can be clearly seen with 2019 being the hottest year on record and the decade of 2011-2020 being the hottest decade on record. Aside from resulting in natural disasters such as bushfires and heatwaves, rising temperatures can create hazardous work conditions and amplify the aforementioned risk factors.

Furthermore, natural disasters associated with rising temperatures, can create hazardous conditions not just associated with heat. For example, there are increasing numbers of extremely severe bushfires/wildfires around the world, as experienced in the 2019/2020 summer bushfires in Victoria and NSW and the 2021 northern hemisphere summer. This resulted in poor air quality which can lead to a multitude of health risks. For more information visit our page on Air quality. 


  • Clothing worn
  • Level of working activity
  • Level of fluid loss and replacement, affecting water and salt balance
  • Acclimatisation
  • Factors such as use of certain medications, medical conditions, physical fitness, obesity, pregnancy.

What are the health effects of exposure to heat?

When the body is exposed to more heat than it can cope with, this leads to heat stress. The body tires to cope mainly by evaporation - sweating. As the temperature in the work environment increases, so too does the body's temperature. This triggers sweating and a flow of blood to the skin where it can be cooled by evaporation. Excessive sweating leads to loss of water from the body, dehydration and loss of salt, resulting in potentially serious health effects.

Possible consequences of excessive heat:

  1. Increase in the likelihood of incidents due to reduced concentration; slippery, sweaty palms; increase of discomfort of some personal protective gear, resulting in reduced protection and unsafe conditions, etc
  2. Skin Rashes: 'prickly heat'
  3. Heat Illness:
    Heat Cramps: Muscle spasms as a result of heavy sweating without restoring the body's salt/water balance.
    Heat Exhaustion: Dehydration following heavy sweating causes clammy, moist skin, weakness and fatigue, nausea, vomiting, headache and giddiness. Reduced blood flow to the brain may lead to fainting.
    Heat Stroke: Hot, dry skin and rapidly rising body temperature can lead to collapse, loss of consciousness, convulsions, even death
  4. Aggravation of other medical conditions and illnesses: for example, high blood pressure or heart disease due to increased load on the heart
  5. Aggravation of the effects of other hazards: through interaction with other workplace hazards such as noise or exposure to toxic substances heat can compound their effects
  6. Reproductive Disorders: may affect sperm count or the health of the foetus.

Some of the problems and their symptoms experienced in the temperature range between a comfortable zone (20C - 27°C) and the highest tolerable limits (for most people) are summarized in the table below:

Problems and Symptoms Caused by Hot Temperatures

Temperature range (°C) Effects
20 - 27 °C Comfort zone Maximum efficiency
As temperature increases.....


  • Increased irritability
  • Loss of concentration
  • Loss of efficiency in mental tasks
Mental Problems

Increase of errors:

  • Loss of efficiency in skilled tasks
  • More incidents
Pyscho-physiological problems

Loss of performance of heavy work:

  • Disturbed water and electrolyte balance
  • Heavy load on heart and circulation
  • Fatigue and threat of exhaustion
Physiological problems
35 - 40°C Limit of high temperature tolerance

(From the Canadian Centre for Occupational Health and Safety: Hot Environments - Health Effects) See also Hot Environments - Control Measures

Who is at risk?

Workers in a variety of occupations may be exposed to heat stress. For example, working in any, or a combination of, the following conditions:

  • outdoor workers - such as construction and building workers, gardeners, etc - particularly during summer months;
  • occupations where there are plant or processes which generate radiant heat. These include: bakeries, kitchens, laundries, foundries, boiler rooms, steelworks and in other manufacturing processes. Workers in these industries become 'acclimatised' (that is used to) to these conditions to a certain extent. However, this means that when these workers go on leave, when they return they must be given time to re-acclimatise to the hot conditions;
  • hot, stuffy, and poorly ventilated buildings; and
  • working in vehicles.

See also:

  • From this site FAQ Heat: When is it too hot
  • From WorkSafe Victoria:
  • From SafeWorkNSW:
  • From SafeWork WA, a 2019 "Alert" Warning to guard against heat stress at work
  • SWA has general Information and has developed a Guide for managing the risks of working in heat  which provides advice on reviewing the workplace to make sure workers are safe.  This is particularly for workers subject to hot conditions indoors, such as hospitality workers in kitchens, factory workers who use hot machinery, and construction workers who go into roof cavities with no air flow.
  • From SafeWork Queensland:  Heat Stress
  • the UK's Health and Safety Executive (HSE), Temperature section on their website and guidelines Heat Stress in the Workplace
  • From the US Occupational Safety and Health Authority, a Heat Stress Card [pdf] which provides tips and precautions to help prevent heat-related deaths and injuries.
  • An information page on heat and its effects from the Canadian Centre for Occupational Health and Safety
  • Australian Standards (go to the SAI Global website for information on how to purchase these):
    • AS 4502 (several parts) - provide guidance on the Selection, Care and Use of Clothing for the Protection against Heat and Fire.
    • AS 1668.2-2012 The use of ventilation and airconditioning in buildings - Mechanical ventilation in buildings which provides that the temperature should be maintained in the range of 18 - 30°Celsius
    • various other Australian Standards
  • From the UK's peak union council, the TUC:
    • a policy position: The case for a legally enforceable maximum temperature [pdf
    • A guide Temperature at Work Temperature for health and safety reps which looks at what the law says about temperature in the workplace and the recommended temperatures for different types of working environment.
  • From the USA's OHS regulator, OSHA  Heat illness prevention campaign.
Last amended October 2021