6B.4
WIND CHILL AND THE DEVELOPMENT OF FROSTBITE IN THE FACE
Michel B. Ducharme, Defence Research and Development Canada, Toronto, ON, Canada; and D. Brajkovic
Cold wind increases the likelihood of developing freezing injuries on exposed skin, particularly in the face. This observation was reported by several Arctic and Antarctic explorers and by many researchers over the years. Despite this, very few studies have systematically described the effect of the wind chill on the development of frostbite in the face. More studies have described the effect of the wind chill on the development of frostbite in the fingers. The objective of the present study was to describe the effect of cold winds on skin temperatures and heat losses from 5 different parts of the face (chin, nose, right cheek, left cheekbone, forehead), and the time required to develop frostbite during exposure to cold. Twelve subjects (6 males and 6 females) were exposed to sixteen 45 min tests where the wind intensity varied between 0, 16 and 32 km/h. The tests were conducted at 0, -10, -20, -30, -40 and -50°C (only 0 km/h wind was present at -50°C). During the tests, the subjects were dressed for thermal comfort, and rested seated while facing the wind with their bare face fully exposed to the cold wind. Each test was terminated when the elapsed time reached 45 min, the skin temperature reached -2°C or when frostnip developed. During the tests, thermal comfort rating and pain rating on the face was recorded every 15 min. The results shows that no frostnip was observed at 0°C and -10°C for any wind intensity. The frequency of frostnip development increases inversely with temperature, while the time to develop frostnip increases with temperature. At -20°C, 17 and 58% of the subjects developed frostnip for the 16 and 32 km/h wind conditions, while at -30 and -40°C, all the subjects developed frostnip at those conditions. For the no wind conditions, 0, 11, 22, and 60% of the subjects developed frostnip for the -20, -30, -40 and -50°C conditions, respectively. The time to develop frostnip decreased from 20 min at -20°C for the 16 and 32 km/h wind conditions to 14, 4, 2.5 and 1.5 min for the -30°C and 16 km/h, -30°C and 32 km/h, -40°C and 16 km/h, and -40°C and 32 km/h conditions. It was concluded from these results that the times to develop frostbite estimated from the Sipple-Passel Wind Chill Index are too short and need to be revised.
Session 6B, Human Comfort Indices II: Wind Chill
Tuesday, 29 October 2002, 3:00 PM-4:00 PM
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