Warmth - part 3

Articles In This Section:

· Warmth - part 1

· Warmth - part 2

· Warmth - part 3

· Warmth - part 4

To provide insulation from cold:

1) Warmth of clothing and sleeping bags is directly proportional to thickness and independent of weight. Warmth results from small bodies of dead air enclosed by cell walls or held between numerous fibers. For this reason several layers of fluffy, loose-woven sweaters are better than hard-woven garments weighing several times as much.

2) Down, feathers, and wool, in the order named, are the best insulators. This is true for both sleeping bags and clothes.

3) Sleeping bags should be covered with tightly woven cloth to prevent warm-air permeation as well as to contain the down. A complete hood extending over the head prevents loss of warm air around the shoulders and insulates the neck and head. Heat loss from an unprotected head and neck exceeds that from the remainder of the body when protected by a sleeping bag. Form-fitting design with the outer shell cut larger than the inner shell gives most insulation for least weight.

4) Placing sleeping bags close together conserves body heat. A sheet of cloth over all the bags helps.

5) Insulation is necessary between snow and sleeping bag; the wool, down, or feathers are crushed by body weight to a thin layer having little insulating value. Fir boughs under the tent floor shingled in the usual matter are thoroughly satisfactory. Above timberline some sort of mattress is desirable. Mattresses made of wool and kapok provide ample insulation but are bulky. Modern closed cell foam plastics are also bulky but provide much better insulation than air mattresses, where internal air movements can cause rapid heat loss. Open cell foam is also useful but must be placed in waterproof covers to prevent absorption of moisture. A mattress, air or otherwise, 18 by 36 inches, is wide enough to sleep on and long enough to extend from shoulders to hips. Food bags, boots, and clothing may be placed under the head for a pillow; a rucksack, parka, climbing rope, or other insulating material at hand can be placed under the legs and feet.

6) Damp articles of clothing, whether wet or frozen, are poor heat insulators. Every possible means should be taken to keep all of the clothes dry, especially the inner mitts and socks.

7) Oily skin is a much better heat insulator than wet skin. Too much washing and the elimination of natural skin oils is not desirable.