Thermal Comfort

This information on thermal comfort aims to alert supervisors, staff and students to the health and safety risks associated with working in hot and cold environments and associated strategies to minimise those risks.

The term ‘thermal comfort’ describes a person’s state of mind in terms of whether they feel too hot or too cold. Most concerns that arise from working in heat are due to heat discomfort. It is difficult to satisfy everyone within the same thermal environment due to large variations from person to person.

Other than the variable personal factors, environmental factors which may contribute to issues with thermal comfort are:

• air temperature
• radiant temperature (i.e. the temperature of the walls, floor, windows etc)
• humidity
• air speed
• the amount of physical activity
• the amount and type of clothing worn.

The recommended temperature range to optimise indoor thermal comfort for most people is 19°C to 28°C. This temperature range is appropriate for the sedentary or near sedentary physical activity levels that are typical of general office work. This recommendation assumes that people dress appropriately to the external seasonal demands.

There is no legislation that specifies maximum and minimum temperatures in the workplace.

Why do we have thermal comfort guidelines?

Working in hot or cold conditions without adequate control measures can create a number of adverse health effects ranging from discomfort to serious illness. Under the WHS Act 2011 NSW, the University of Wollongong has a responsibility to provide a safe place to work for staff and students. These guidelines on working in hot or cold conditions are to provide a means of ensuring that supervisors and employees are aware of risks associated with working in these environments and strategies to minimise thermal discomfort or risk of further illness.

Download the Thermal Comfort Guidelines [PDF-122Kb]

When a significant proportion of people in an area are experiencing thermal discomfort the supervisor should investigate the cause(s) and consider making alternative work arrangements for staff and students. The procedures for resolving a workplace hazard or health and safety issue should be followed.

Workplace factors to be considered by the supervisor include:

• level of physical activity in the tasks being performed by staff and students
• temperature of the area
• whether the work performed by staff and students involves safety-critical tasks such as operating machinery or handling chemicals
• specific individual needs such as those arising from medical conditions
• concerns expressed by staff and students.

Thermal comfort versus heat/cold stress

There is a significant difference between thermal discomfort and heat/cold stress. Heat stress may occur in situations where a person's core temperature rises above 38°C and cold stress occurs when a person's core temperature falls below 35°C. Heat stress may occur in environments where there is high temperature (e.g. outdoor manual work in summer), radiant heat (e.g. foundries) or humidity (e.g. mines), a high level of physical activity (e.g. manual labour) or excessive or impervious clothing. Under these conditions, heat loss may no longer be in balance with heat production and heat-related illnesses such as heat cramps, heat exhaustion or heat stroke may occur.

Cold stress may occur in environments where there are low temperatures (which will be aggravated by wind), immersion in water and working in wet clothing (which includes clothes damp from sweat). The local effects of cold stress include frostbite, hypothermia, chilbain and immersion foot.

Workers or students displaying signs or symptoms of heat/cold stress should seek immediate first-aid/medical attention.

How to control the risks

It is important that staff/students are not put in a position where they may be exposed to heat/cold stress. The following risk control strategies should be considered where reasonably practicable:

• modify working practices (such as clothing worn, work rate etc.), to adapt to the thermal environment.
• monitor the thermal conditions and where possible record temperatures.
• provide health surveillance or medical screening for workers who have special requirements such as pregnancy, certain illnesses, disabilities and/or maybe taking medication. Medical advice should be sought if necessary.
• ensure adequate and appropriate risk assessment procedures are in place.
• review working habits and current practices and change (where necessary).
• take regular breaks to cool down in warm situations and heat up in cold situations
• provide additional facilities, e.g. cold water dispensers (water is preferable to caffeine or carbonated drinks) and allow sufficient breaks to enable workers to get cold drinks or cool down
• provide or upgrade air cooling or air conditioning / additional workplace heating
• include thermal comfort as part of workplace risk assessments
• introduce work systems to limit exposure, such as flexible hours or early/late starts to help avoid the worst effects of working in high temperatures or rescheduling field activities in the event of extreme temperatures
• relax formal dress codes
• move workstations away from hot plant or out of direct sunlight
• ensure that personal protective equipment is provided and used if required

Note: The University does not allow radiant bar heaters to be brought in from home and used in the workplace as a result of the fire risk they present  (refer What's On...under your desk?)

Need more information? Please call the WHS Unit on extension 3931.