The Effect of Floor Insulation and Clothing Wetness on Thermal Response of Life Raft Occupants Ezposed to Cold
Inflatable life rafts are the primary evacuation units used by the majority of vessels at sea. In the event of a vessel emergency evacuation all passengers don the provided survival equipment and enter the life raft from the vessel or water. If the passengers do not have additional thermal protection, they are largely dependent on the thermal protection of the life raft to prevent or minimize body heat loss to the environment. The aim of this study was to determine the thermal response of life raft occupants with no additional thermal protection in cold conditions. Five male and three female participants (26.3 ± 6.1 yrs, 84.4 ± 18.5 kg, 175.7 ± 9.6 cm, 23.7 ± 9.1 BF％) were exposed for a maximum of 480 min to four randomly assigned conditions inside the raft: wet clothing with uninflated floor (WU), wet clothing with inflated floor (WI), dry clothing with uninflated floor (DU), and dry clothing with inflated floor (DI). For all trials the ambient conditions were: 5oC air and water temperature, 5m/s wind speed, and 0.5m/s towing speed. During each trial subjects wore a full zip cotton coverall, cotton t-shirt, cotton briefs, and SOLAS approved lifejacket. The extremities were protected against non-freezing cold injuries with wool lined leather mittens, wool socks and 5 mm neoprene boots. Measures of rectal and tympanic temperatures, skin temperature and heat flow at 13 sites, and metabolic rate were continuously recorded during each trial. Baseline measurements were similar across all four conditions (Tre: 36.85±0.04oC; Tty: 36.39±0.01℃; Tsk: 33.02±0.03℃; HF: 60.31±2.47W·m-2; MR: 106.30±49.44W). The duration of exposure for DI (7.76±0.52h) was significantly longer compared to DU (6.49±1.07h) and WI (6.10±1.29h), with the exception of WU (6.37±2.15h). At the end of the exposures, Tre and Tty had decreased from the baseline measurements for all condition. Tre decreased more significantly for the uninflated conditions, WU (34.95±0.73℃) and DU (34.76±0.69℃), compared to the inflated conditions, WI (35.65±0.50℃) and DI (35.72±0.49℃). However, the clothing wetness had no significant effect on the Tre cooling. Tty decreased similar amounts across all four conditions indicating that neither the clothing wetness nor floor insulation had a significant effect on Tty cooling: WU (35.63±0.47℃), WI (35.12±0.82℃), DU (35.34±0.58℃), and DI (35.30±0.41℃). Tsk decreased across all conditions but significantly more during the wet conditions, WU (23.48±2.44℃) and WI (24.01±1.91℃), compared to the dry conditions, DU (26.84±1.61℃) and DI (27.72±1.52℃). The difference between the baseline and exposure average HF was significantly greater for the wet conditions, WU (183.20±29.27W·m-2) and WI (171.95±29.63W·m-2), compared to the dry conditions,DU (124.59±32.53W·m-2) and DI (120.67±23.03W·m-2). The floor had no significant effect on Tsk or HF. The average MR was greater during the exposures than baseline for all conditions with a more significant increase during the wet conditions, WU (65.17±27.12W) and WI (69.48±44.39W), compared to the dry conditions, DU (37.90±28.89W) and (5.44±39.00W). Similar to Tsk and HF, the floor had no significant effect on the change in average MR. In conclusion; clothing wetness had the biggest effect on Tsk, HF, and MR, with floor insulation having the biggest effect on Tre.
Kerri-Ann Evely Brian Farnworth Scott N. MacKinnon Fabien A. Basset Lawrence Mak Andrew Kuczora Stephen S. Cheung Michel B. DuCharme Robert Brown James Boone
Memorial University of Newfoundland, St. John’s, Newfoundland, Canada, A1C 5S7 Helly Hansen Canada Limited, Kelowna, Canada, V1V 2C1 National Research Council Canada, Institute for Ocean Technology, St. John’s, Newfoundland,Canada, A Brock University, St. Catherine’s, Ontario, Canada, L2S 3A1 Defence R&D Canada, Quebec City, Quebec, Canada, G3J 1X5 Offshore Safety and Survival Centre, St. John’s, Newfoundland, Canada, A1C 5R3
国际会议
17th World Congress on Ergonomics(第十七届国际人类工效学大会)
北京
英文
1-10
2009-08-09（万方平台首次上网日期，不代表论文的发表时间）