Hot Stuff! Dealing with heat stress in the workplace

In many jobs, heat stress can be an issue throughout the year, but it is also important to manage exposure during summer months where there can be an increased risk of it occurring for others. Employers and employees must be aware of how to work safely in heat, the factors that can lead to heat stress, and how to reduce the risk of it occurring.

What is heat stress?

Heat stress occurs when the body’s means of controlling its internal temperature starts to fail. Air temperature, work rate, humidity and work clothing are all factors that can cause heat stress. Factors may not always be obvious, so it is important to maintain regular contact with the workforce and conditions within the working environment.

What are the effects of heat stress?

Heat stress can affect individuals in different ways, and some are more susceptible than others. Typical symptoms include:

• An inability to concentrate
• Muscle cramps
• Heat rash
• Severe thirst (at the late stages)
• Fainting
• Heat exhaustion (fatigue, giddiness, nausea, headache, moist skin)
• Heat stroke (hot dry skin, confusion, convulsions, loss of consciousness)
• Severe cases if not properly dealt with can result in death
• Where does heat stress occur?
• Common internal places where heat stress can occur are listed below, however, during summer months and periods of high temperature or humidity, it can also occur whilst outside or under canopies.
• Glass and rubber manufacturing plants
• Mines
• Confined spaces
• Foundries
• Brick-firing and ceramics plants
• Boiler rooms
• Bakeries and kitchens

What do I need to do about heat stress?

Over time, people can adapt to hot working conditions by sweating more, changing their behaviours to cool down, removing clothing, taking cool drinks, reducing their work rate and sitting in the shade. However, these are not always possible, particularly when PPE and RPE must be worn.

Where there is a reasonable possibility of heat stress occurring you must carry out a risk assessment that makes consideration of the following:

• Work rate – the harder someone works, the more heat they generate
• Working climate – air temperature, humidity, air movement, working near heat sources
• Clothing and protective equipment – regulating the body’s temperature becomes a lot harder
• Individual susceptibility – age, build and medical factors could affect an individual’s tolerance

How can I reduce the risks?

• Control the temperature using engineering solutions, change processes, using fans and air conditioning
• Provide mechanical aids where possible to reduce the work rate
• Regulate exposure through job rotation, restricting access and allowing additional breaks
• Prevent dehydration by providing cool drinking water and space to rest
• Provide PPE that is specialised to incorporate cooling systems and breathable fabrics
• Provide training for your workers and sufficient information and instruction to avoid the factors that cause heat stress, but also how to deal with the symptoms
• Allow workers to acclimatise to their environment
• Identify workers who are more susceptible to heat stress because of illness or a condition that could heighten their risk such as expectant mothers or those with heart conditions. Consider additional support from an occupational health professional.
• Further advice and guidance
• The effects of high temperatures can be routine or seasonal, but either way, it is vital that employers do all they can to identify potential occasions for exposure to high temperatures and how they can be sufficiently controlled. For indoor working environments, guidance is available in the HSE Approved Code of Practice L24 for the Workplace (Health, Safety and Welfare) Regulations 1992.
• Further support and advice on this topic are available from our range of training and consultancy services.

Dave Wright GradIOSH