Managing the risks of working in heat

As summer approaches, so do the dangers of working outside during hot weather. Knowing how to work safely in hot weather can help prevent heat stress injuries and heat stroke, the most serious heat-related disorder. Heat stroke occurs when the body can no longer control its temperature. When this occurs, body temperature can rise to 106° F or higher within 10 to 15 minutes. If emergency treatment is not provided, heat stroke can cause death or permanent disability.

This article provides practical advice for preventing heat illness and the health and safety risks arising from working in hot conditions. Typical workplaces may be outdoors, inside where it’s hot, or where the work itself generates heat. Following are actions and measures to prevent or minimise the likelihood of heat illness.

Heat stress can be caused by physical exertion outdoors in hot weather or working in hot, cramped work areas that have inadequate ventilation. Heat illness occurs when the body cannot sufficiently cool itself. You absorb more heat from your environment than you can get rid of through perspiration or other cooling mechanisms.

Factors that contribute to this include:

  • Amount of air movement
  • Clothing
  • Humidity
  • Physical activity (metabolic heat load)
  • Radiant temperature of surroundings
  • Temperature.

Heat illness covers a range of medical conditions that can arise when the body is unable to properly cope with working in heat. These conditions include:

  • Fainting
  • Heat cramps
  • Heat exhaustion
  • Heat fatigue
  • Heat stroke
  • Rashes
  • worsening of pre-existing illnesses and conditions.

Signs and symptoms of heat illness include headache, nausea, dizziness, weakness, irritability, thirst, cramps and heavy sweating. Clumsiness, collapse and convulsions may also be experienced as a result of heat illness. Tellingly, skin can become cold and clammy, despite the heat.

Workers with these signs or symptoms need to seek immediate medical attention.  Employers have a duty of care to all workers, and can take a number of steps to help them cope with the heat and ensure they do not suffer the negative effects of ‘good’ weather. In addition to an employer’s legal requirements to protect workers, regulating the temperature of the work environment has also been shown to be important in maintaining productivity. Research has shown that temperature generally impacts work performance.

Monitoring thermal comfort: There is no law or official guidance governing the maximum temperature in the workplace, but the law demands that workplaces are well ventilated and not subject to extreme temperatures. The Health and Safety Executive suggests that if more than 10% of staff in an air conditioned office (or 15% in a naturally ventilated office) complain about being too hot, a thermal comfort risk assessment should be carried out.

Introducing physical intervention to regulate temperature: Introducing air conditioning or fans into the workplace, creating barriers between the heat source and workers, or reducing the physical effort required by workers.

Regulating exposure to extreme temperature: Reducing the time spent in hot environments or near the heat source.

Encouraging workers to stay hydrated: Making sure that employees take on enough fluids during the day by offering easy access to water.

Training staff: Informing workers so they are aware of the impact of heat on their work and the symptoms of heat stress, heat exhaustion and heat stroke. Helping them to understand how to combat the effects of heat, and how to recognise when heat is taking its toll on them or others.

Acclimatization: Allowing time for workers to adjust to hot conditions by restricting the time they spend exposed to extreme temperatures.

Monitoring the health of workers at risk: Being aware of the health needs of people with diabetes, lung or heart disease and reducing their exposure to extreme heat.