Hot weather in the workplace | A H&S perspective

Hot weather in the workplace | A H&S perspective

Does the current heatwave give you cause for concern about the temperature in your workplace?

Hot weather is great for a day on the beach, but not necessarily in the workplace. People usually best work at temperatures between 16°C and 24°C. Although this varies depending on the kind of work being done. Strenuous work is better performed at slightly lower temperatures than office work.

The Chartered Institute of Building Services Engineers recommend the following temperatures:

  • heavy work in factories: 13°C
  • light work in factories: 16°C
  • hospital wards and shops: 18°C
  • offices and dining rooms: 20°C

Temperatures that vary too much from this can become a health and safety issue…

If workers get too hot, they risk dizziness, fainting, or even heat cramps. In very hot conditions, your body’s blood temperature rises. If it goes above 39°C, you risk heat stroke or collapse. Delirium or confusion may occur above 41°C and blood temperatures at this level can prove fatal.

But even at lower temperatures, heat leads to a loss of concentration and increased tiredness, which means workers are more likely to put themselves and others at risk. Working in the sun also increases the risk of skin cancer.

The legal position on hot weather in the workplace

As an employer, you must provide a working environment that as far as ‘reasonably practicable’ is safe and without risks to health. You also have to assess the risks and put in place any necessary prevention or control measures.

However, the law does not specify a maximum temperature for workers – the Workplace (Health, Safety & Welfare) Regulations 1992 simply state temperatures inside workplace buildings must be ‘reasonable’. Additionally, the Approved Code of Practice to the Workplace Regulations say ‘all reasonable steps should be taken to achieve a comfortable temperature’.

The Trades Union Congress suggest a maximum temperature of 30°C (27°C for those doing strenuous work), so that employers and workers know when action must be taken. 

The Approved Code of Practice gives the following examples of what can be done to ensure a reasonably comfortable temperature:

  • insulating hot plants or pipes
  • providing air cooling plants
  • shading windows
  • sighting workplaces away from places subject to radiant heat

If this is not sufficient, the Code says employers must install local cooling systems, increase ventilation, or install fans. It also says other factors must be taken into account when assessing what a ‘reasonable temperature’ is. This could include:

  • protective clothing
  • physical activity
  • radiant heat
  • humidity
  • air movement
  • length of time someone does a job

More regulation to get you hot under the collar

In addition, the Code requires employers to provide a suitable number of thermometers to allow workers to check indoor temperatures.

The regulations also say employers must provide ‘effective and suitable ventilation’. However, make sure this isn’t simply done by opening doors that act as fire doors.

Although the Workplace Regulations only apply to indoor workplaces, that doesn’t mean you don’t also have a duty to employees working outside.

All employers have a general duty to protect the Health & Safety of the workforce under the Health & Safety at Work etc Act 1974. The risks of working in hot temperatures, or exposure to the sun, must also be assessed and controlled under the Management of Health & Safety at Work Regulations 1999. Other regulations employers must comply with in hot conditions include the:

  • Personal Protective Equipment at Work Regulations 1992 – say personal protective equipment (PPE) must be suitable for the risks, for the workers using it, and for the working environment. This means if PPE is used in hot weather (inside or out), it must be designed to keep workers as cool as possible
  • Manual Handling Operations Regulations 1992 – requires employers to take into account other factors including hot and humid conditions
  • Health & Safety (Display Screen Equipment) Regulations 1992 – requires that ‘equipment belonging to any workstations shall not produce excess heat which could cause discomfort to operators or users’
  • Management of Health & Safety at Work Regulations 1999 – specifically says employers have to assess risks to pregnant women from extremes of heat as they tolerate heat less well. Also says young workers must not be employed in situations where they are likely to be exposed to extremes of heat

Indoor work           

Being too hot is one of the biggest causes of complaint by workers during a spell of warm weather – especially when they’re not used to it!

However, measuring air temperature from a thermometer is only one part of what must be considered – as humidity, heat sources, clothing, any breeze or wind, all impact how people are affected by heat. Also, heat effects vary according to a person’s weight and age. You can more accurately assess the situation in the workplace using a wet bulb globe thermometer or an electronic equivalent that measures humidity: the comfort range for humidity is between 40%-70%.

A good rule of thumb in determining if it’s too hot is whether or not workers feel comfortable – if they don’t, then something should be done. Simple measures worth considering include:

  • relaxing the dress code – the issue will be whether or not the clothing is acceptable in the context of the job is done
  • redesigning the work area – moving people away from windows or installing reflective film or blinds to windows
  • installing fans or natural ventilation -providing fans or windows that open can help workers feel cooler
  • allowing flexible working arrangements – giving staff the flexibility to finish either earlier or later can help.

If none of these measures sufficiently reduce the level of heat and staff are still uncomfortable, then a competent heating and ventilation engineer should be employed to survey the workplace. They would recommend a permanent solution.

Indoor workers in factories, mines, boiler rooms, kitchens and laundries are even more at risk of heat stress or dehydration. Seek professional advice on both reducing heat and protecting such workers. Workers should also be told how to avoid heat stress and dehydration, and how to recognise early symptoms.

Outdoor work

There are around 100,000 new cases of skin cancer every year in the UK, albeit under 10% are malignant. Most cases are caused by exposure to sunlight and are easily preventable.

Outside workers should be given sunscreen and hats. Employers should also make sure protective clothing is light and suitable. Staff should always have access to fresh water and regular breaks. Ideally, work should be organised so workers aren’t outside during the hottest part of the day.

Working in outside heat can also lead to dehydration and heat stress, and cause fatigue, muscle cramps, rashes, fainting. And in severe cases loss of consciousness. Make sure an adequate risk assessment has been carried out and that controls are in place to prevent workers suffering from sunstroke, excess sun exposure, dehydration or heat stress.

For more information about how to manage health & safety in the workplace – have a look here.

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