Temperature and Work

Introduction Thermometer

The Workplace (Health, Safety and Welfare) Regulations (Northern Ireland) 1993 detail the requirements for the temperature in indoor workplaces.

The Regulations state that during working hours the temperature in all workplaces inside buildings shall be reasonable.

Minimum Temperature

Guidance states that the temperature in the workplace should normally be at least 16 degrees Celsius unless the work requires physical effort in which case the temperature should be at least 13 degrees Celsius. The temperature in workrooms should provide reasonable comfort without the need for special clothing. A workroom is a room where people normally work for more than short periods.

These temperatures do not apply to rooms (or parts of rooms) where it would be impractical to maintain such temperatures, such as rooms which have to be open to the outside or where food has to be kept cold. In such cases, the temperature should be as close to those mentioned above as is practical.

A thermometer must be provided so that workers can check the temperature in any workplace inside the building. The availability of a thermometer is required under the Regulations.

In general, employers should try to ensure that the temperature at the workplace is pleasant, rather than too hot or too cold. Employers should also try to ensure that the atmosphere is dry rather than damp or humid.  The best that can be realistically achieved is a thermal environment which satisfies the majority of people in the workplace, or put more simply, 'reasonably comfortable'.

There is no legal minimum outdoor working temperature so employers will have to rely on thermal risk assessments to maintain a reasonable level of thermal comfort and rely on controls as provided by job rotation, more regular breaks and cold weather clothing. 

What can an employee do?

If an employer fails to provide a reasonable temperature, formally raise the matter with the employer or workplace safety representative or union representative. A complaint can also be forwarded to your local council or HSENI.

What would be useful is for an employee or safety representative to record and verify temperatures over a number of days and present the findings to the employer as evidence of adverse temperatures presenting problems of ill-health.

Maximum Temperature

There is no law for maximum working temperature, or when it's too hot to work.

Those employees exposed to extreme heat can suffer symptoms that include discomfort, dehydration and exhaustion. Each of these can harm productivity and increase absenteeism.

Employers have a legal duty to ensure the welfare of their employees and workers. In extremes of temperature this is centred on the idea of “thermal comfort” - how acceptable a person considers their current temperature.

Thermal comfort is determined by both environmental factors (such as the sources of heat in the workplace and the degree of humidity) and personal factors (such as clothing worn and the physical exertion required by the work).

As thermal comfort depends on the individual as well as the environment, the easiest way to establish whether a workplace is thermally comfortable is to ask the workers or their representatives. At a bare minimum, at least 80% must be satisfied with the thermal environment, according to the Health and Safety Executive. If fewer than 80% are satisfied, the employer should take action.

Examining the air temperature of the workplace alone may be insufficient as a measure of thermal comfort, as this may still be inappropriate if there is, for instance, excess humidity or the nature of the work is physically demanding.

What can be done if the temperature is excessive?

The following list provides a number of practical ways to address any problems with excess temperature:

  • air conditioning units can be adjusted or provided if not already existing
  • increasing the number of open windows
  • provide staff with fans
  • install blinds on windows – this can reduce heat gain through windows
  • provision of cold drinking water
  • insulating hot plants or pipework
  • place workstations away from direct sunlight
  • job rotation
  • relax requirements on the wearing of a uniform

For more detailed information, please see the HSE GB website at the following link:

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