How to Achieve Thermal Comfort

At this time of year we spend our lives constantly having to adapt between freezing external temperatures, and very warm internal workplaces/ homes. We often are asked by our clients about thermal comfort and what are the legal minimum and maximum temperatures for a workplace.

What is Thermal Comfort?

Thermal comfort relates to how a worker feels whilst at work and whether they feel too hot or cold. There are many factors that can affect thermal comfort, and it is a very subjective topic. What is comfortable for one person may not be for another, and often people who work closely together have very different ideas regarding what is reasonable when providing a comfortable thermal environment.

There are many factors that can affect thermal comfort, including:

• Humidity levels
• Heat sources in the workplace
• Drafts, ventilation units and other forms of airflow
• Floor level (heat always rises, so those working on higher floors often experience higher temperatures)
• Glazing units and proximity of working near them
• Physical demand of the work
• Personal factors (clothing, gender, personal preference).

What does the law require?

Section 2(2)e), The Health and Safety at Work etc Act 1974 gives the broad-based objective to provide a reasonable working environment. By implication this means that the temperature should be monitored to ensure it does not cause risk of ill-health or safety to employees.

Reg 7, The Workplace (Health, Safety & Welfare) Regulations 1992 go further and state that during working hours, the temperature in all workplaces inside buildings shall be reasonable (the word “shall” means this is an absolute requirement, i.e. non-negotiable). They further require that:

• Thermal insulation is installed where necessary
• Consideration is given to the type of work that is carried out (i.e. sedentary or physical)
• Excessive effects of sunlight on temperature are avoided
• Methods of heating/cooling do not emit fumes, gas or vapour of such character and extent to be injurious or offensive to any person, and
• A sufficient number of thermometers are provided to enable workers to determine the workplace temperature.

To help employers interpret what is “reasonably practicable” there is an Approved Code of Practice which (L24 (Second edition) Published 2013) which is produced by the Health and Safety Executive (HSE) which provides examples of what employers should be doing in a range of working environments.

Is there a minimum and maximum temperature?

The simple answer is no, although the Approved Code of Practice does state that the minimum temperature for sedentary workers, e.g. in offices and call centres, should be 16 ̊C, and where physical work is completed it should be at least 13 ̊C. However, an assessment should be completed to determine what measures are needed, taking the work into account. For example, people undertaking significant manual handling throughout the day may find that 13 ̊C is too warm, whilst those sitting still all day are likely feel chilly at 16   ̊ C.

BSEN 9241

“Ergonomic requirements for office work with visual display terminals” recommends a thermal range of 19-23 ̊C where office and other sedentary type work is completed.

So How do we ensure Thermal Comfort?

Clearly an assessment is needed of your work environments and activities. For those working in very hot temperatures (e.g. food manufacturing, foundries etc.) or very cold temperatures (e.g. food storage, working outdoors) the nature of the work will determine the thermal environment. The employer is expected to ensure there are mechanisms in place to reduce the risks and provide some respite. Examples for high temperature environments include provision of cold water, good airflow, light-weight PPE (where feasible) and cooler rest areas.

The HSE recommends that employers consider six basic factors. These are:

Environmental Factors:

1. Air temperature: Is the temperature set between 19-23°C, or what is reasonable for the worker group.
2. Radiant temperature: Examples include: the sun, fire, electric fires; ovens; kiln walls; cookers; dryers; hot surfaces and machinery, molten metals etc.
3. Air velocity: the speed of air moving across the employee and may help cool them if the air is cooler than the environment but can cause discomfort is the air movement is excessive.
4. Humidity: a range of 40-60%, with an optimum level of 50% is recommended. Low humidity can induce feelings of dry and itchy eyes, runny nose and lethargy whilst high humidity levels reduce a person’s ability to self-regulate temperature through sweating and can contribute towards heat fatigue/stress.
5. Clothing insulation: Wearing too much clothing or PPE is often a primary cause of heat stress even when the temperature is not considered warm or hot. If the clothing does not provide enough insulation, the employee may be at risk from hypothermia in cold conditions.
6. Metabolic heat: The more physical the work, the more heat that is produced. Metabolic heat is variable in individual’s dependant on their age, weight, fitness level etc so maintaining a constant temperature is vital.

If you would like to know more about how to assess your thermal environment, please do not hesitate to call us on 01622 717700. It costs nothing to talk.