Thermal comfort in the workplace

Thermal comfort is a very personal issue.  Comfort in an office environment is not easy to define, and specific limits cannot be given to define comfort from discomfort. Comfort depends both on environmental and individual factors.

Environmental factors

There a number of environmental factors that can affect thermal comfort. These include:

• air temperature
• humidity
• solar heat gain
• air movement

For example, a hot and dry environment (low humidity) tends to be much more tolerable than the same temperature with high humidity. If a person's location in the office exposes them to sunlight, they may be very uncomfortable despite others in the office who are not in direct sunlight being comfortable.

Individual factors

Personal thermal comfort depends on a range of factors these include:

1. Activity level – more active jobs generate more heat
2. Clothing – If the weather outside is cold and people dress for that and then come into a warm office environment they are more likely to become uncomfortable
3. Body Mass Index – People with higher levels of body fat are likely to be less heat tolerant and more cold tolerant

As a result of the numerous environmental and individual factors it is not possible to specify absolute and precise measurements which indicate comfort or discomfort.

Measures for controlling thermal comfort

While the combination of environment and individual factors make thermal comfort a difficult issue to manage, there are measures that can be put in place:

1. Wearing layers of clothing: It's advisable to wear multiple layers to ensure you can peel off or put on a layer as thermal comfort changes
2. Controlling solar heat gain: Make use of window blinds to stop direct sunlight, or move to a different location out of the sunlight
3. Controlling other heat sources: Turn off unnecessary heat producing equipment, or relocate equipment that may blow out air etc
4. Making use of fans
5. Using portable cooling/heating units or heat pumps
6. Keeping your fluids up throughout the day
7. Taking regular breaks, going to a cooler/warmer area if necessary

Safety equipment

The use of safety equipment must not be compromised.  It is not acceptable for people to stop wearing any safety equipment including gloves, gowns, footwear, masks and so on because of the temperature.

If equipment cannot be worn because of thermal discomfort then that particular work should cease until such time as equipment can be worn comfortably.

When to leave work/close down operations

Supervisors need to be aware of conditions when thermal discomfort may occur.  Glass buildings on a sunny day may have a considerable greenhouse effect even when the air temperature outside is low.  There is a need for awareness.  There is often more of a problem in the office areas towards the top of high rise buildings.

There may be quite localised areas where thermal discomfort is common.  It is not possible to give specific levels at which work can or cannot proceed, so supervisors need to make a decision if and when the issue arises.

If staff are complaining of problems that should be enough of an indication to take action.  In the first instance see if local control measures can alleviate the problem, it may be possible to rotate staff if there are enough people who can do the task without discomfort.

If none of these measures are sufficient and employees continue to complain of discomfort then options include, closing that work area and moving the staff to another area, or if there is no other alternative sending the staff home.

Thermal discomfort action notification.

If supervisors have to close down processes or send people home they must notify the following

• Head of Department
• Departmental Health and Safety Officer
• Property Services
• Health and Safety Manager

Download the thermal discomfort action notification template

Hazard Identification and Control

Where action has been taken to control thermal discomfort then follow up assessment is needed.  This will look at the level of discomfort, frequency of such occasions, causes and possible control measures.