Heat stress can be a concern year-round in many jobs, but the risk often increases during the hot summer months.
It's essential that you and your employees understand how to work safely in hot conditions, recognise the factors that contribute to heat stress, and take steps to minimise the risk.
What is heat stress?
Heat stress happens when the body can no longer effectively regulate its internal temperature. Several factors can contribute to this, including air temperature, physical workload, humidity, and the type of clothing worn.
Please note: The risk of heat stress may not be immediately apparent to someone simply passing through the workplace.
What are the effects of heat stress?
Heat stress affects people in different ways, and some individuals are more vulnerable than others. Common symptoms include:
- Difficulty concentrating
- Muscle cramps
- Heat rash
- Severe thirst (a late sign of heat stress)
- Fainting
- Heat exhaustion (fatigue, dizziness, nausea, headache, and moist skin)
- Heat stroke (hot, dry skin, confusion, convulsions, and loss of consciousness). Heat stroke is the most serious condition and can be fatal if not treated promptly.
Where does heat stress occur?
Heat stress can arise in a variety of workplaces, particularly where hot environments are caused by industrial processes or confined spaces. Common examples include:
- Glass and rubber manufacturing plants
- Mines
- Compressed air tunnels
- Power stations (conventional and nuclear)
- Foundries and smelting operations
- Brick-firing and ceramics plants
- Boiler rooms
- Bakeries and kitchens
- Laundries
In these industries, working in high heat may be routine. In other workplaces, the risk may be occasional, influenced by the type of work and environmental factors such as seasonal changes in outdoor temperature.
How to Carry Out an Assessment: What Should I Consider in the Risk Assessment?
When conducting a risk assessment for heat stress, consider the following key factors:
- Work rate: The more physically demanding the task, the more body heat is produced.
- Working environment: Assess air temperature, humidity, airflow, and any heat sources nearby.
- Clothing and protective equipment: These can reduce the body’s ability to cool itself through sweating.
- Individual factors: Age, body type, and medical conditions can affect how well someone tolerates heat.
Start by speaking with the workers involved and any workplace safety representatives to find out if anyone is experiencing early symptoms of heat stress.
If concerns are raised, consider consulting professionals such as occupational hygienists or occupational health experts to assess the risks more thoroughly.
How can I reduce the risks?
- Control Temperature Through Engineering Measures:
Modify processes, use fans or air conditioning, and install physical barriers to reduce exposure to radiant heat.
- Use Mechanical Aids:
Provide mechanical equipment where possible to reduce physical effort and lower the work rate.
- Limit Exposure to Hot Environments:
- Allow entry only when temperatures are below a specified level or during cooler parts of the day.
- Issue permits to work that define time limits for tasks in hot conditions.
- Schedule regular rest breaks and provide cool rest areas.
- Prevent Dehydration:
Sweating regulates body temperature but causes water loss. Provide cool drinking water and encourage frequent, small sips before, during (where possible), and after work.
- Provide Suitable Personal Protective Equipment (PPE):
Use specialised PPE with cooling features or breathable fabrics. Be aware that some protective gear can increase the risk of heat stress.
- Train Workers:
Educate all workers—especially new and young staff—on heat stress risks, symptoms, safe practices, and emergency procedures.
- Allow for Acclimatisation:
Give workers time to adapt to hot environments and identify those who are properly acclimatised or medically fit for such work.
- Identify Vulnerable Workers:
Recognise individuals who may be more at risk due to medical conditions, medications, or pregnancy. Seek advice from an occupational health professional when needed.
Further reading
To find out more see: https://www.hse.gov.uk/pubns/indg451.htm
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