Wildland firefighters’ thermal exposure in relation to suppression tasks

Abstract

The main purpose of this study was to characterise the thermal environment and risk of heat burns of wildland firefighters in relation to the suppression tasks performed in real wildland fires. Measurements of air temperature and heat flux were performed by affixing heat flux and ambient temperature sensors on the outer and inner surface of the wildland firefighters’ protective garments. Suppression time was divided according to the task performed in direct attack, backfire, mop-up and patrol. These tasks accounted for 95.2 ± 78.4, 103.3 ± 41.7, 80.5 ± 24.8 and 71.3 ± 53.0 min, respectively. Overall, the mean heat flux was higher during backfire (2165 ± 1604 W m−2) than in direct attack (558 ± 344 W m−2), mop-up (371 ± 254 W m−2) and patrol (354 ± 307 W m−2). However, during the direct attack, average and maximum thermal dose was ~94 and ~110 (kW m−2)4/3 s, respectively. These values are within the threshold of pain and first-degree burns. However, no first-degree burns were reported for the sample. Overall, the thermal exposure measured may be considered light. However, high thermal exposure values may be obtained at specific moments, which may cause first-degree burns in wildland firefighters.