Joined: 14 May 2007
Location: Gallatin, TN
Real Name: Jason W. Gatliff
|Posted: Tue May 22, 2007 11:21 pm Post subject: The Scientific Approach to Dressing in Layers for Winter
|When dressing in layers for winter treks, it's helpful to remember that each layer must perform a specific task. The innermost layer must allow water vapor to escape from your skin, as water conducts heat roughly 15 times faster than air of the same temperature. Protein based fabrics such as wool or silk work well. Plant fibers, such as linen and cotton, tend to absorb moisture, trapping right next to your skin, so should be avoided as an inner layer.
The middle layer must create a dead air space in which to trap warm air within the fibers of the fabric. It's your insulating layer, and the dead air space is referred to as "loft". Wool offers a tremendous amount to loft so is preferred to most who trek in seriously cold climates. In warmer climates, a middle layer of relative coarse linen may trap enough warm air in the spaces between the threads to serve the purposes. This is the principal behind the "fishnet" type long underwear sold in some regions.
The outermost layer is a windbreak that prevents the warm air trapped in the insulating layer from being blown away. Any thighly woven fabric or leather will serve the purpose as an outer layer.
So, if you keep these principals in mind you can often dress in fewer layers of appropriate materials, and not have to deal with the need to don many layers of inappropriate materials.
Submitted by: Swann - firstname.lastname@example.org on October 23, 2000
Jason W. Gatliff