As temperatures rise during the summer months, employers should consider how heat may affect the health, safety and wellbeing of their workforce.
High temperatures can make people uncomfortable, tired and less able to concentrate. For employees carrying out physical work, working outdoors or wearing personal protective equipment, the risks may be even greater.
The Health and Safety Executive provides guidance to help employers assess and manage workplace temperatures, reduce the risk of dehydration and heat stress, and keep employees safe during warmer weather.
There is no legal maximum temperature that determines when a workplace is too hot. This is because working environments can vary significantly. Some workplaces experience high temperatures because of seasonal weather, while others, such as bakeries, kitchens, factories and foundries, may be hot because of the work being carried out.
However, this does not mean employers can ignore uncomfortable or potentially unsafe conditions.
Employers are required to provide a reasonable indoor working temperature and assess risks that may affect their employees. Heat should be treated like any other workplace hazard, with suitable control measures introduced where necessary. Employers should also consult workers or their representatives when deciding how high or low temperatures will be managed.
For indoor workplaces, the minimum temperature should normally be at least 16°C, or 13°C where the work involves significant physical effort.
A thermometer reading alone does not provide a complete picture of how comfortable or safe a working environment is.
The HSE identifies six factors that can influence thermal comfort:
For example, an employee carrying out strenuous work in protective clothing may be at risk of overheating even when the air temperature does not appear particularly high. Similarly, high humidity can prevent sweat from evaporating effectively, reducing the body’s ability to cool itself.
Employers should therefore consider the working environment, the activity being completed and the needs of individual employees when assessing temperature-related risks.
There are several relatively simple measures that can help make indoor workplaces more comfortable during hot weather.
The HSE advises employers to consider:
Any changes to clothing must not compromise safety. Where PPE is required, employees should continue to wear it correctly.
Personal protective equipment can increase the risk of overheating because it may be heavy, restrictive or prevent sweat from evaporating.
Where PPE is necessary, employers may need to reduce work rates, introduce more frequent breaks, rotate employees and provide longer recovery periods. Work could also be moved to a cooler time of day where possible.
Workers should be encouraged to remove PPE during designated rest periods when it is safe to do so. Employers should also review whether lighter or more breathable equipment can provide the same level of protection.
PPE should never be loosened, unfastened or worn incorrectly simply to increase airflow, as this may expose the wearer to the hazard it was intended to control.
Outdoor workers may face additional risks from heat, direct sunlight and prolonged exposure to changing weather conditions.
The HSE recommends scheduling work for cooler parts of the day, providing shaded working and rest areas, introducing more frequent breaks and ensuring workers have free access to cool drinking water.
Employers should also consider the longer-term effects of sun exposure. Too much sunlight can cause sunburn and skin damage and may increase the risk of skin cancer over time.
The weather may also affect a worker’s ability to concentrate or operate machinery safely, making suitable planning and supervision particularly important.
Dehydration can affect both an employee’s health and their ability to work safely.
Employees working in hot conditions should be encouraged to drink cool water regularly and in small amounts. Employers should not wait until workers say they are thirsty, as thirst can be an early indication that dehydration is already beginning.
Where employees are unable to drink while carrying out a task, perhaps because of the PPE being worn, suitable opportunities should be provided to hydrate before work begins and during rest periods.
Heat stress occurs when the body is no longer able to control its internal temperature effectively. The risk can be influenced by temperature, humidity, workload, clothing, PPE and the individual worker’s health or physical characteristics.
Possible signs include:
More serious heat stroke symptoms can include hot, dry skin, confusion, convulsions and loss of consciousness. Heat stroke can be fatal if it is not identified and addressed quickly.
Employees should be trained to recognise the early signs of heat-related illness, understand safe working practices and know the organisation’s emergency procedures.
One of the simplest ways to identify temperature-related problems is to speak to employees.
Workers should be encouraged to report uncomfortable conditions, symptoms of heat stress, problems with ventilation or situations where PPE is making work particularly difficult.
The HSE’s workplace temperature checklist asks employers to consider employee complaints, changing temperatures, heat-producing equipment, humidity, air movement, workload and PPE. When two or more concerns are identified, employers should assess the risks and determine what additional controls may be needed.
Managing workplace temperature is not about reaching one specific thermometer reading. It requires employers to understand the working environment, the demands of each task and the needs of the people carrying it out.
By reviewing risk assessments, consulting employees and introducing practical measures such as ventilation, drinking water, shaded rest areas and flexible working arrangements, businesses can help protect their workforce throughout periods of warmer weather.
Effective health and safety arrangements should remain responsive to changing conditions. When the temperature rises, taking action early can help prevent discomfort from developing into a more serious safety or health risk.
