Extreme environment clothing normally
for arctic or mountainous areas on land,
although it is sometimes used for survival
suits worn by mariners. The basic approach
is to insulate one's body from
heat loss, and keep liquid water
or ice out of the insulation.
The usual clothing is
and mittens, gaiters and booties. In
high wind-chills, it may be supplemented
by a mask, usually of oiled wool. In
arctic areas, the typical modern
insulation is very fine hydrophobic
polyester fiber batting sewn in laps
between a nylon shell. The sewing must
not compress or quilt the insulation,
because the heat leaks out through the
Most designers now include a moisture
barrier on the inner side to prevent condensation
from a body's moisture from condensing and
freezing in the insulation. Sometimes the
moisture barrier has several layers of aluminized
plastic film to reflect
infrared back to the body. If plastic
film is near the skin, usually some lightweight
between the skin and the film, for comfort.
The feet of booties are usually insulated
by a thick layer of flexible closed-cell
plastic foam, covered with a boot sole.
Traditional tribal insulations are mouth-chewed
oiled furs from the winter-killed arctic
animals, with the fur turned toward the
body, or in heavy garments, with two layers,
the inner turned away from the body, and
the outer turned toward the body. The outer
layers of skin breaks the wind, and the
inner reduces condensation in the fur.
Even in modern garments, certain furs
Wolverine) are prized for a hood lining,
because they do not collect ice crystals
from one's breath.
For use in wet areas, the insulation
is reduced (because the temperature is above
freezing), and a barrier that passes water
vapor, but not liquid water is sewn into
the outer shell. This barrier passes gaseous
water from one's body, yet prevents precipitation
from soaking the insulation.
The most effective modern fluid barrier
and consists of an expanded felt or mesh
of polytetrafluoroethylene (trade name
The basic principle is that the plastic
felt does not wet, and the pores are small
enough so water's surface tension will resist
high wind pressures. At the same time, the
pores are large enough to easily pass water
Gore-Tex is mechanically fragile, and
is usually bonded to a polyester fabric,
and sewn inside a nylon outer shell.
Marine survival suits come in two different
types, wet and dry. Dry suits are very similar
to arctic clothing, except with a
shell, and closed-cell flexible plastic
foam for insulation and flotation. Some
have vents that claim to pass air but not
Wet suits use foam rubber insulation.
Water in the foam warms. They remain warm
when water gets inside, do not handle the
most extreme cold, and are profoundly uncomfortable
for extended wear.