- Author
- Firm, J. | Romet, T. T.
- Title
- Role of the Mosture/Vapor Barrier in the Retention of Metabolic Heat During Fire Fighting.
- Coporate
- Defense and Civil Institute of Environmental Medicine, Ontario, Canada
- Report
- DCIEM-88-RR-40; Project 51C3-52T-DCCEM 73, October 1988, 86 p.
- Distribution
- Available from National Technical Information Service
- Keywords
- fire fighting | moisture | vapors | heat stress | turnout coats | evaporation
- Identifiers
- core temperature; skin temperature; evaporation fluid loss; heart rate; neoprene; gore-tex; thermal comfort
- Abstract
- The relationship between metabolic heat build-up and the vapor permeability of the barrier layer in fire fighter turnout clothing was examined under a variety of conditions. Laboratory exercise tasks were used to simulate the work of fire fighters performing under three different environmental conditions, cold, hot, and extended very hot conditions. The laboratory studies wsere followed by a field trial in which true fire fighting activities were performed. The clothing elements examined included three outer shells, five moisture/vapor barrier configurations, and two thermal liners. Ten parameters indicated of thermal physiological strain were monitored in eight professional fire fighters to assess the role of the barrier in the retention of metabolic heat. The results showed that the moisture/vapor barrier material/configuration was the dominant factor in determining thermal physiological strain, with the shell and linear playing very minor roles. Differences in strain as a function of barrier were discernible even under low to moderate stress, but became more pronounced with higher ambient temperatures and longer work periods. The laboratory results were clearly substantiated during the field trial. It is concluded that a full vapor barrier of a material such as neoprene leads to significantly higher thermal physiological strain than a vapor permeable water barrier of a material such as Gore-tex. Partial coverage barriers of either material provide even greater reduction in strain, and omission of the barrier entirely is best from a physiological perspective. The best fire fighter turnout clothing will be a compromise between the requirement to protect against external hazards and the need to dissipate metabolically generated heat.