Thermal Resistance of Inflatable and Non-Inflatable Floors of One-Man Life Rafts for the CF-188 Escape System

Abstract : The purpose of this study was to define, using humans as heat source, the difference in thermal resistance of inflatable and non-inflatable floors of one-man life rafts for the CF 188 Escape System of the Canadian Forces. Three life rafts were tested: two with an inflatable floor and one with a non-inflatable floor. Eight subjects of both genders were used to evaluate the thermal resistance of the floors because humans provide adequate heat transfer and pressure on the floors of the life rafts. Skin heat flow and temperatures were recorded from 4 sites on each subject, namely the right and left buttocks and the right and left calves. The results were averaged from the last 10 min of the 1-hour immersion in 5 degrees centigrade water. The results showed that on average, the skin heat loss and temperatures for the four sites were respectively lower by 33% (74 W/m2) and higher by 12 degrees centigrade for the inflatable floors as compared to the non-inflatable floors. This resulted in a floor thermal resistance 10 to 12 times higher for the inflatable floors (0.71 + 0.25 and 0.60 +0.16 Clo) as compared to the non-inflatable floor (0.06 + 0.01 Clo). In conclusion, a life raft with an inflatable floor will significantly reduce the heat loss and the likelihood of developing hypothermia during deployment in cold water when compared to a life raft with a non-inflatable floor.