Accession Number : ADA305730

Title :   Prediction Of Cold Sea Survival Time,

Corporate Author : DEFENCE AND CIVIL INST OF ENVIRONMENTAL MEDICINE DOWNSVIEW (ONTARIO)

Personal Author(s) : Tikuisis, Peter

PDF Url : ADA305730

Report Date : FEB 1996

Pagination or Media Count : 28

Abstract : Despite advances in personal protective equipment and locator technologies, circumstances can lead to life-threatening exposures at sea. Of particular concern is the survival time (ST) when a human is immersed in cold water. Estimations of ST is difficult since reliable controlled data are not available. However, studies on accidental immersion are sufficient to begin the construction and calibration of a predictive ST model. The model is based on the cylindrical core-shell concept of heat conduction with internal heat production augmented by shivering. Variables include ambient temperature, clothing protection (with and without leakage), subject characteristics, sea state, and level of immersion. If heat loss exceeds one's maximal rate of heat production, then ST is largely determined by the body's rate of cooling. Conversely, if a heat balance can be established, then ST is dependent on the depletion flme of one's energy capacity based on glycogen stores. ST is defined by the deep core temperature reaching 30 deg C. As an example, the predicted ST for a healthy normal sedentary individual immersed in a heavy sea condition at 5 deg C are 1.9, 2.3, 4.8, 12.6, and 24.2 h for nude, shirt + sweater, shirt + anti-exposure suit, shirt + dry immersion suit, and 4 mm neoprene wet suit conditions, respectively. While the model predictions must be considered speculative, it can potentially serve as a valuable resource and decision aid. At present, it would be prudent to apply the predictions in a relative vs absolute sense; i.e., for comparative purposes.

Descriptors :   *OCEANS, *EXPOSURE(PHYSIOLOGY), *COLD WATER, *IMMERSION, *COLD TOLERANCE, *SHIVERING, CONTROL, DEPLETION, TEMPERATURE, PRODUCTION, PREDICTIONS, MODELS, CAPACITY(QUANTITY), ENERGY, RATES, COOLING, TIME, RELIABILITY, THERMAL CONDUCTIVITY, PROTECTIVE EQUIPMENT, RESOURCES, CALIBRATION, HEAT, SURVIVAL(PERSONNEL), CLOTHING, DECISION AIDS, SEA STATES, HEAT BALANCE, HEAT LOSS, ACCIDENTS.

Subject Categories : Stress Physiology
      Physical and Dynamic Oceanography

Distribution Statement : APPROVED FOR PUBLIC RELEASE