By Colton Beckwith, an RPC Student.
In this essay I will be discussing heat transfer and layering in clothing, particularly as it relates to SAR operations.
I will begin by discussing the pros and cons of various clothing materials.
Cotton’s pros include its breathability and its cool-keeping elements. It is also water resistant if woven tightly. Additionally, cotton is flammable, making it a good fire starting material, but this can be a bad thing for firefighters trying to put out a blaze. In the way of cons, in SAR “Cotton kills” is a common saying, as cotton dries slowly, which can cause the body temperature to plummet if the cotton becomes wet. Also cotton tears easily.
Wool fabrics come from sheep and are well insulated. The oils in wool help repel water. One con of wool fabrics is that if it becomes wet it has an unpleasant odor.
Finally, there are synthetic materials such as Polypropylene. These are man-made materials which give you the comfort and warmth of natural materials. Synthetics are tear resistant and are water resistant, making it a good insulator. However, synthetics can shrink and melt.
I will now discuss heat transfer.
Dead air space is the air trapped between two materials. This allows for air pockets to form, which are important when trying to keep warm. Also, moving air passing through fibers will aid heat transfer from your body. Lastly, there are jackets called vents that allow heat to escape without having to remove the jacket.
Lastly, I will discuss the five main layers. Layering is important to keep your body temperature under control. Here are the different types of layers:
Starting on the innermost layer, the underneath layer is the layer closest to the skin. It is important that this layer is non-cotton, as it will get wet in rainy weather or when perspiring. This layer is meant to wick away moisture to keep you comfortable.
Second is the wicking layer. Part of this layer may be in contact with the skin as well. Synthetics like polyester work well for this layer. It can be used for several purposes, such as a wicking material, or to keep moisture off of your skin. This depends on the material.l
Next is the clothing layer. This is most likely a normal outfit, such as pants and a shirt. This layer should allow moisture to escape. Also, it should not be tight, as the first two layers should.
Fourth is the insulation layer, which is necessary when working in cold environments. This could be a fleece or sweater. This layer is meant to trap in heat.
Finally, the shell layer is the outermost layer. This layer protects you from wet weather, sun, and wind. This could be a synthetic parka or a jacket.
Please leave your feedback here or in the comments. – ColtonBeckwith RPC