Too hot to handle: heat stress in the workplace
Heat stress is when temperatures get so high that the body is put under strain and cannot regulate its internal temperature. Problems that arise due to exposure to excessive heat can escalate quickly, leading to delirium, organ damage and even death.
For many people, heat stress is a seasonal issue, but for some workers, heat is a constant problem in the workplace. For example, indoors in kitchens and bakeries, or in environments where large machinery that emits a lot of heat is in operation, high temperatures are a permanent issue. Heat can also affect employees who need to wear some types of protective clothing while working.
Symptoms of heat stress include:
- Fatigue
- Difficulty concentrating
- Extreme thirst
- Heat rash
- Muscle cramps
- Nausea
- Headache
- Light-headedness
- Fainting
- Heatstroke
Severe heat stroke can lead to loss of consciousness and potentially death. There is also evidence to suggest a link between increases in temperature above comfortable levels and increases in accidents in the workplace.
Heat at work and the law
Employers are required by law to ensure that the temperature in the workplace is “reasonable”. The Workplace (Health, Safety and Welfare) Regulations 1992 do not specify minimum and maximum temperatures. Although the Approved Code of Practice recommends that temperatures should not fall below 13°C for physical work and 16°C for general work, there is no recommended upper limit. UK guidance on thermal comfort recommends taking several factors into consideration when assessing the impact of temperatures:
- Air temperature
- Radiant temperature
- Air velocity
- Humidity
- Insulated clothing
- Metabolic heat
The impact of metabolic rate is an important factor when considering acceptable temperatures for the workplace. The level of activity makes a significant difference because of the additional heat produced by the body during physical work.
Things you can do to help with heat stress in the workplace
- Increase air circulation with natural ventilation and air conditioning. If your premises already have air conditioning, ensure that it is operating at full capacity, and upgrade where necessary. A mobile air conditioner is ideal in a temporary setting or for short-term use.
- Encourage workers to keep hydrated by drinking plenty of fluids, particularly water. If possible, provide water coolers to give workers quick access to chilled water. Use signage to remind your staff to drink water.
- Make sure that essential workwear is designed to keep workers as comfortable as possible in high temperatures. Adjust uniform requirements in hot weather, where possible.
- Training and awareness: ensure that staff recognise the symptoms of heat stress and know where to get help in the event of a problem.
- Frequent rest breaks: where possible, give workers access to cooler areas to rest, ideally hourly in extreme heat.
Conduct a heat stress risk assessment
You can create your own risk assessment or use a pre-prepared checklist, such as the Health and Safety Executive (HSE) Thermal Comfort Checklist. The HSE recommends that employers carry out a thermal risk assessment as a minimum where complaints about heat discomfort are raised by:
- More than 10% of workers in an air conditioned office.
- More than 15% of workers in an office with natural ventilation.
- More than 20% of workers in indoor premises such as factories and workshops.