2018 has seen one of the hottest UK summers on record followed by a balmy autumn. But we knew that it couldn’t last. The mercury has dropped and it’s time to find ways of keeping warm. It’s easy to adjust the temperature at home but we have less control in the workplace. What do we do if the workplace is too cold?
According to the gov.uk website there isn’t a law for a minimum (too cold) working temperature.
During working hours the temperature in all indoor workplaces must be reasonable, with guidance suggesting a minimum of 16ºC or 13ºC if employees are doing physical work.
Employers must stick to health and safety at work law, including:
- keeping the temperature at a comfortable level
- providing clean and fresh air
The Health and Safety Executive (HSE) does not have specific guidance for working in cold environments where temperatures are below 13°C. In these situations you can comply with the law if you work in accordance with the British Standards listed at the end of this post.
Assessing Thermal Comfort in the Workplace
So, is it warm enough in your workplace? Ask a number of your employees and you’ll get varying answers. How one feels is a subjective matter. One person’s warm is another person’s baltic. But, if there’s a general consensus, it’s likely that your employees will talk to you if the workplace temperature isn’t comfortable. In this situation, you can use a Thermal Comfort Checklist to assess the thermal discomfort of the workplace. The HSE provides the version included here. If you get two or more ‘YES’ answers, there may be a risk of thermal discomfort and you may need to carry out a more detailed risk assessment.
1. Air temperature
The temperature of the air surrounding the body.
- Does the air feel warm or hot?
- Does the temperature in the workplace fluctuate during a normal working day?
- Does the temperature in the workplace change a lot during hot or cold seasonal variations?
2. Radiant temperature
This is heat transferred by thermal radiation to the body.
- Is there a heat source in the environment?
- Is there any equipment that produces steam?
- Is the workplace affected by external weather conditions?
We are sensitive to humidity because we use evaporative cooling to rid ourselves of waste heat, which evaporates more slowly under humid conditions.
- Do your employees complain that the air is too dry?
- Do your employees complain that the air is humid?
- Are your employees wearing PPE that is vapour impermeable?
4. Air movement
Air movement, or air velocity, across the body can influence heat flow to and from the body. Air velocity can vary in speed and direction, and can be related to discomfort due to draughts.
- Is cold or warm air blowing directly into the workspace?
- Are employees complaining of draught?
5. Metabolic rate
The heat a human generates through activity is metabolic heat. The clothing that insulates that heat and provides protection from the external environment should also be considered.
- Are employees sedentary in cool or cold environments?
- Is PPE being worn that protects against harmful toxins, chemicals, asbestos, flames, extreme heat, etc.?
- Can employees make individual alterations to their clothing in response to the thermal environment?
- Is respiratory protection being worn?
7. What your employees think
- Do your employees think that there is a thermal comfort problem?
How the Human Body Responds
The human body is an awesome machine, it responds in different ways to thermal discomfort, depending on the individual body and its environment. Thermo-sensors provide the temperature sensation and are located in the human body, central nervous system and skin.
The various ways that the human body responds to its environment include:
- Behavioural responses – putting on clothes, turning up the heating, moving away from a draught, changing posture.
- Hairs standing on end – to reduce heat loss by maintaining a layer of still air between body and environment.
- Shivering – produces heat through muscular activity.
- Sweating – allows cooling by evaporation.
- Vasodilation and vasoconstriction – blood vessels supplying blood to the skin can swell or dilate, this is called vasodilation. It causes more heat to be carried by the blood to the skin where it can be lost to the air. When blood vessels shrink down again it is called vasoconstriction.
It is a combination of these factors – along with personal factors such as motivation, acclimatisation and tolerance – that affects your thermal comfort.
The internal temperature of the human body should be maintained around 37 °C. This relates to the fact that there is a dynamic heat balance between the human body and the environment.
The British Standards List
This is not an exhaustive list but provides a framework around which you can develop your risk assessment and start managing the problem. You may need to refer to other standards listed elsewhere, depending on your operational circumstances.
British standards for assessing cold stress in the workplace:
- BS EN ISO 13732-3:2008 Ergonomics of the thermal environment. Methods for the assessment of human responses to contact with surfaces. Cold surfaces.
- BS EN ISO 13732-3 describes methods for the assessment of the risk of cold injury and other adverse effects when a cold surface is touched by bare hand/finger skin.
- BS EN ISO 13732-3 provides ergonomics data to establish temperature limit values for cold solid surfaces. The values established can be used in the development of special standards, where surface temperature limit values are required.
- The data of BS EN ISO 13732-3 will be applicable to all fields where cold solid surfaces cause a risk of acute effects: pain, numbness and frostbite.
- The data of BS EN ISO 13732-3 is not limited to the hands but apply to human skin in general.
- BS EN ISO 13732-3 is applicable to the healthy skin of adults (females and males). It also gives considerations on the extension of this data.
The most current versions of these British Standards can be obtained in PDF or hard copy formats from BSI, email: firstname.lastname@example.org.
Sources: gov.uk, Health and Safety Executive, British Standards Institute