The Country Fire Authority (CFA) in Victoria, Australia, conducted extensive body monitoring trials, using the latest technology in order to assess the physical and mental effects of heat stress on firefighters in action. Based on the results the CFA was able to make several essential key considerations for the treatment and prevention of this life threathening condition, writes Peter Langridge, health and wellbeing officer for the CFA.

Heatstress is one of the top three leading causes of injury during bush fire suppression and an increasing cause of injury during structural firefighting. While personal protective clothing (PPC) provides considerable protection, current structural PPC is heavy, multilayered and contains a moisture barrier that traps air, creating a microclimate between the skin and clothing. Consequently, during physical exertion and exposure to a hot environment, firefighters lose their ability to dissipate body heat through sweating ? the natural means of thermoregulation. These factors increase the vulnerability of firefighters to thermal strain.

The human body will tolerate a core temperature increase of only 3°C before sweating fails to cool the body and heat stroke occurs. As the surroundings become hotter, all methods of heat elimination? radiation, conduction and convection? become ineffective in protecting the firefighter against heat from these mechanisms.

For the safety of firefighters, it is important to keep cardiovascular and thermoregulatory strain below critical levels while working in PPC. Under high ambient temperature, the body may experience exhaustion, mental confusion, disorientation, loss of consciousness, heart attack and, in extreme cases, death. A number of rehabilitation procedures exist within the fire service to decrease incidence of heat stress such as crew rotation, fluid replacement, education about signs of heat illness and passive cooling (for example, opening of PPC or sitting in a shaded area). Although these current practices help to relieve heat stress, the National Fire Protection Association Rehabilitation Standard (NFPA 1584) states that active cooling methods should be included in standard operating procedures.