Toronto • May 28-29, 2010 • Student Day and Workshops: May 27
Program > Saturday > 14:00 > Session symposium2. Symposium: Firefighter health and safety
Paper: Physical demands and air management during simulated fire fighting tasks
Author(s) and Affiliation(s):
Richard Hughson, University of Waterloo
Michael Williams-Bell, University of Waterloo
Andrew Kostiuk, Toronto Fire Services
Geoff Boisseau, Toronto Fire Services
John McGill, Toronto Fire Services
Day/Time: Saturday at 14:00
Room: Giovanni Room, 2nd Floor
Objectives:
Toronto firefighters are confronted by the second greatest volume of high-rise buildings, subway systems and large box stores in North America. During emergency operations, the lives of the firefighters depend on the finite volume of air carried in the self-contained breathing apparatus (SCBA). We measured energy expenditures and the rates of air consumption of firefighters performing typical work tasks while wearing full turnout gear and breathing from the SCBA.
Methods:
Thirty-three Toronto firefighters (3 women) volunteered to participate in this study. The SCBA mask was integrated with a Cosmed K4b2 portable gas analysis system fitted to the expired port and not affecting in any way the normal performance of the device. This enabled measurement of breath-by-breath air consumption along with oxygen uptake (VO2) and carbon dioxide output (VCO2). Three different scenarios were investigated: a maximal stair climb to consumption of 55% of the nominal “30-minute” cylinder; a fifth floor search and rescue; and a subway search and rescue scenario. Firefighters were instructed to work at their normal pace; in the subway they worked in teams of two.
Results:
The two scenarios involving stair climbing evoked the greatest increases in energy requirements to 70 ± 10% and 65 ± 10% of maximum VO2. The subway scenario required 49 ± 8% peak. Heart rate increased to 88 ± 4%, 88 ± 6%, and 76 ± 7% of maximum. The ratio of VCO2 to VO2 was consistently greater than 1.0 in both stair climbing scenarios reflecting excessive production of lactic acid. Air consumption during the stair climbing and fifth floor scenarios ranged from about 60 to >125 L/min, and from 40 to 80 L/min during the subway scenario.
Conclusions:
The high rate of air consumption resulted in sounding of low air alarm indicating 25% air remaining as early as 8 min in the stair climb, and it would have sounded by approximately 9 and 11 min in the fifth floor and subway scenarios. These results give evidence for reduced durations of work shifts to avoid placing firefighters in dangerous situations where they could deplete their air supply. The data provide evidence of lactic acid production markedly above what would be anticipated at the same percentage of maximum VO2 in activities other than fire fighting.
References:
F. M. Williams-Bell, G. Boisseau, J. McGill, A. Kostiuk, and R. L. Hughson. Air management and physiological responses during simulated firefighting tasks in a high-rise structure. Applied Ergonomics 41: 251-259, 2010.
