Smart suits keeps chopper crews warm in freezing water, cool in hot working conditions

“Melting requires heat, which the wax takes from the body, cooling the wearer in the helicopter cabin on warm days”, explain product designers Kristine Holbø and Jarl Reitan of SINTEF Health Research.

“In the laboratory, we have demonstrated that the skin temperature of the wearers does not rise by much. We registered that our test subjects did not begin to sweat until as long as 80 minutes at an air temperature of 27 degrees, because the melting process actually lasts such a long time” says senior scientist Hilde Færevik, also of SINTEF Health Research.

An analogy from everyday life is a glass of water with ice-cubes. Until all the ice has melted, the water in the glass remains at the melting temperature of ice, i.e. zero degrees Celsius. Only when all the ice has thawed will the temperature of the water begin to rise.

The laboratory studies also showed that the subjects felt much more comfortable in the new suits than the old ones.

At the same time, Færevik and her colleagues at SINTEF have documented that the new suit offers good protection against loss of heat when the wearer is in the sea.

“We believe that this is both because the paraffin wax releases the stored heat as it returns to the solid state, and because the suit contains extra insulation at the places where the body releases most heat,” she explains.

The suit ensures that the skin temperature of the wearer never falls below 15 degrees anywhere on the body in the course of six hours in water at a temperature of two degrees Celsius.

This ensures, for example, that helicopter passengers retain their ability to grasp things during long involuntary stays in the sea.

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