With expected temperatures due to rise significantly over the next few days (that’s if the Met Office are to be believed) some employers may be faced with complaints about the workplace being too hot. (I know – they should be grateful!!) So we draw your attention to the following guidance –
Temperatures in the workplace are covered by the Workplace (Health, Safety and Welfare) Regulations 1992, which place a legal obligation on employers to provide a “reasonable” temperature in the workplace. The Approved Code of Practice suggests a minimum temperature in workrooms should normally be at least 16 degrees Celsius – or 13 degrees Celsius if much of the work indoors involves severe physical effort. These temperatures are not absolute legal requirements; the employer’s essential duty is to determine what reasonable comfort will be in the particular circumstances.
A meaningful figure cannot be given at the upper end of the scale. This is because the factors, other than air temperature which determine thermal comfort, i.e. radiant temperature, humidity and air velocity become more significant and the interplay between them more complex as temperatures rise. In addition to the Workplace Regulations, the Management of Health and Safety at Work Regulations 1999 require employers to make a suitable assessment of the risks to the health and safety of their workers, and take action where necessary and where reasonably practicable.
Environmental factors (such as humidity and sources of heat in the workplace) combine with personal factors (such as the clothing being worn and how physically demanding the work is) to influence what is called ‘thermal comfort’. So the term ‘thermal comfort’ describes a person’s psychological state of mind and is usually referred to in terms of whether someone is feeling too hot or too cold.
Thermal comfort is very difficult to define because you need to take into account a range of environmental and personal factors when deciding what will make people feel comfortable. These factors make up what is known as the ‘human thermal environment’. The best that you can realistically hope to achieve is a thermal environment that satisfies the majority of people in the workplace, or put more simply, ‘reasonable comfort’. The HSE considers 80% of occupants as a reasonable limit for the minimum number of people who should be thermally comfortable in an environment. So thermal comfort is not measured by air temperature, but by the number of employees complaining of thermal discomfort.
Why is thermal comfort important?
People working in uncomfortably hot and cold environments are more likely to behave unsafely because their ability to make decisions and/or perform manual tasks deteriorates.
People employ adaptive strategies to cope with their thermal environment eg putting on or removing clothing, unconscious changes in posture, choice of heating, moving to cooler locations away from heat sources etc. The problems arise when this choice (to remove jacket, or move away from heat source) is removed, and people are no longer able to adapt. In many instances the environment within which people work is a product of the processes of the job they are doing, so they are unable to adapt to their environment.
The six factors affecting thermal comfort are both environmental and personal. These factors may be independent of each other, but together contribute to a worker’s thermal comfort.
Environmental factors: Air temperature; Radiant temperature; Air velocity and Humidity
Personal factors: Clothing Insulation; Metabolic heat
Controls
There are eight main methods of control which you can use:
• Control the heat source
• Control the environment
• Separate the source of heat or cold from the worker
• Control the task
• Control the clothing
• Allow for the worker to make behavioural adaptations
• Protect the worker
• Monitor the worker
