Did you know that being submerged in cold water for just 20 minutes can lead to hypothermia, unconsciousness, and even death?
How long a person can survive in cold water primarily depends on the water’s temperature, exposure time, and the thermal insulation of the victim’s protective clothing. The insulation within clothing is measured with the unit “Clo.” By determining the rate at which heat is lost from the body, as well as the difference in temperature between the skin and the water, predictions can be made of the rate a person’s body temperature will drop when submerged in water.
For example, one “Clo” represents the thermal comfort of an average person in business clothing in a room temperature indoor environment. Fractions of this thermal comfort are what are perceived when worn in the water, because water transfers heat out of the body 25 times faster than air.