Toronto • May 28-29, 2010 • Student Day and Workshops: May 27
Program > Saturday > 14:00 > Session symposium2. Symposium: Firefighter health and safety
Paper: Laboratory studies to establish the basis for thermoregulatory guidelines and cooling strategies for firefighters
Author(s) and Affiliation(s):
Tom McLellan, Defence Research and Development Canada (DRDC), Toronto
Glen Selkirk, Defence Research and Development Canada (DRDC), Toronto
Day/Time: Saturday at 14:00
Room: Giovanni Room, 2nd Floor
Objectives:
Research conducted at Defence Research and Development Canada (DRDC), Toronto on behalf of the Toronto Fire Service has focused on the thermoregulatory challenge of wearing protective clothing in hot environments and the development of hydration and cooling strategies to enhance the firefighters’ safety and work performance.
Methods:
Heat-stress guidelines have been developed on the basis of laboratory studies conducted with firefighters wearing their protective ensemble and carrying their self-contained breathing apparatus while working at various intensities in 25, 30 and 35ºC. Thermal and evaporative resistance coefficients were also obtained from thermal manikin testing that allowed the human physiological responses to be compared with modeled data. Predicted continuous work times were then generated using a heat strain model that established limits for increases in body temperature to 38.5ºC. Subsequent experiments were conducted to examine the role of fluid replacement and active cooling to establish optimal work and rest strategies.
Results:
An important finding from the initial testing phase was the demonstrated need to provide active cooling during rehabilitation periods. Following exhaustive exercise at 35ºC, for example, core temperature continued to increase from 39.0ºC to 39.5ºC during a 30-min seated recovery period when most of the protective clothing had been removed. An optimal strategy with a rehydration schedule to replenish about 70% of the sweat loss together with forearm and hand immersion during 20-min rehabilitation periods reduced the rise in body core temperature and extended tolerance time and work time by 90% compared with conditions of fluid restriction and no cooling.
Conclusions:
A strategy for effectively minimizing the rate of heat accumulation and for providing optimal cooling has been developed during this collaborative work between DRDC and TFS. The primary result is a “heat stress wheel” that can be used by incident commanders to assign work tasks and to determine requirements for fluid replacement and active cooling to increase the safety for the firefighters working in a hot stressful environment.
References:
G.A. Selkirk and T.M. McLellan. Physical work limits for Toronto Firefighters in warm environments. J. Occup. Environ. Hygiene 1:199-212, 2004.
G.A. Selkirk, T.M. McLellan and J. Wong. Active versus passive cooling during work in warm environments while wearing firefighting protective clothing. J. Occup. Enivron. Hygiene 1:521-531, 2004.
G.A. Selkirk, T.M. McLellan and J. Wong. Fluid replacement strategies for firefighters during work in warm environments while wearing firefighting protective clothing. Ergonomics 49:418-433, 2006.
T.M. McLellan, G.A. Selkirk. The management of heat stress for the firefighter: a review of work conducted on behalf of the Toronto Fire Service. Industrial Health 44: 414-426, 2006.
