Cold Weather Operations Dress Code

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Cold weather operations dress code

Cold Weather Operations Dress Code

1. Lt Arne Alexander Strand, Norwegian School of Winter Warfare

Introduction

Good and appropriate clothing is vital to maintain combat readiness in a unit. It is vital that each

soldier and particularly each NCO and officer has been taught proper use of cold weatherclothing in various conditions. This requires knowledge of how the human body produces heat

and how the choice of correct clothing can regulate and maintain the heat according to the

activity taking place. Insulating layers of clothes in themselves do not produce any heat but

retain the body heat more or less effectively according to their characteristics. Other kinds of

clothing offer protection against wind and rain. Fabrics that are loose and porous are felt to be

warmer than dense and hard fabrics because the fibres contain more air.

All fabrics issued for use in the Military today have been tested and meet the requirements set

in relation to abrasion, hygiene, fire resistance etc. Non-military items, which apparently look

similar, have not been exposed to the same testing, therefore it is vital that the issued

equipment is used and also used in the right way. Together this will provide sufficient comfortand combat endurance.

In this article I will focus on the most important principles of body heat loss, how to dress when

in cold weather operations and how to stay warm and dry.

Body heat loss

To make sure that the body has the right working temperature (+ 37 Centigrade) heat loss and

heat production must be in balance all the time. The key to the right balance is found in the

clothing and how it is regulated.

Heat loss from the body mainly occurs in four different ways (Fig 1):

By circulation (1) The heated air layer next to the skin leaks out and is replaced by cold air

(convection). This is particularly noticeable in a cold wind.

By contact (2) The contact between the body and, for instance, the surface you lie or sit on

"steals" heat from the body (conduction).

By radiation (3) The body releases heat its surroundings when these are colder than the body.This is of little importance to a person who is correctly dressed for cold weather.

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By evaporation (4) When the perspiration on the body and in the clothes evaporates.

Evaporation requires heat to occur and, hence, heat is drawn from the body.

Fig 1: Body heat loss

Half of the body's heat production escapes from an uncovered head and neck. In other words,

these parts of the body are extremely important when it comes to getting rid of excess heat

(bareheaded, shirt open at the neck) and retaining body heat (cap, scarf, polo neck and

balaclava).

The extremities - hands, feet, ears, nose and genitals are the most exposed to frostbite (Fig 2).

Small cylindrical limbs, for instance the fingers, have a great heat loss because of a relatively

large surface compared to volume. By using mittens instead of finger gloves the total surfacebecomes smaller and it will be easier to keep the hands warm.

Fig 2: Exposed parts of the body

Multilayer system

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The purpose of clothing is to help us maintain the right body temperature. The clothes are

meant to insulate against cold and protect against rain and snow. They are also meant to give a

possibility for ventilation so that excess heat, if necessary, can escape with the body dampness.

A single layer is rarely sufficient, several thin

layers of clothes offer insulating layers trapping air between them thus giving better insulationrather than just one thick layer. The protection against wind is achieved by using an outer layer

of windproof material. An outer layer of waterproof or impregnated clothing offers protection

against wetness. The greatest challenge in winter is the heat regulation. It is important to vary

the clothes and the number of items worn when moving around in order not to become

overheated. Therefore the clothing is composed according to the multilayer principle (Fig 3)

which means several thin layers of clothing, with each item correctly fitted and worn. With

multiple layers you can select and adjust the combination according to the prevailing climate.

The clothing fabric has to be chosen carefully. The clothing can be divided into three main

layers, the inner layer (also known as base layer or next to skin), the middle layer and the outer

layer.

Fig 3: Multilayer system

The inner layer is next to the skin and its main task is to keep you warm and move vapour away

from the body. I discourage the use of cotton underwear, especially in cold weather. Cotton

absorbs and accumulates moisture next to the skin during strenuous activity. Heat from the skin

will cause the moisture to evaporate and drop the bodys core temperature. Cotton also reduces

moisture penetration through layers and to the outside. There are two good alternatives; wool

and a blend of wool and synthetic fibres. Synthetic fibres in general absorb very little vapour and

transport it away from the body, but have poor insulating properties when wet. Wool is less

durable but can absorb a great amount of vapour equal to its own weight, transport moisture

away from the body and maintains its insulating properties even when wet. Blends feature a

mixture of the characteristics.

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The middle layer must be warm and insulating suitable for low level activities as well as for

rest stops or bivouacs. Again there are two alternatives; wool or fleece in synthetic fibre. As forunderwear wool absorbs moisture, but maintains its insulating properties even when wet. While

fleece in synthetic fibre has both insulating and vapour transportation characteristics and it also

dries faster. Fleece will not insulate when it is wet.

The outer layer must be windproof and moisture permeable and it should be water resistant or

waterproof. Note that a completely waterproof outer layer will not make evaporation through the

fabric possible. The outer layer is meant to trap the air in the insulating layer. Ideally you wantyour clothing in this layer to be breathable and dry quickly, as well as keep you dry and protect

you against the wind.

How to keep warm

To keep warm and comfortable in inclement weather, in both rest and activity, you need to know

how to use your clothes correctly. Wrong use of clothing will give wrong body temperature.

During physical activities it is often sufficient to wear a base layer with an outer shell protecting

against the wind. A rule of thumb is to wear as little as possible and ventilate well. Warm airraises so the transportation of heat and moisture ventilates up and out. Clothes should be worn

so that the temperature can be regulated by opening up or closing at the wrists, ankles, neck,

front and waist. This is what we call the chimney principle or chimney ventilation. If the clothes

are to give the desired effect, they have to be loose-fitting and offer the possibility of ventilation.

Trousers tightly fitting around the waist or clothes that are squeezed together by a belt or straps

prevent ventilation.

The human body perspires producing moisture on the skin and it is important to keep this to a

minimum. When activity stops, the moisture gets cold, even turns to ice inside or outside the

clothes. This will draw heat from the body until it evaporates. Therefore, it is vital to get rid of

this heat and moisture by ventilation when you stop, then closethe chimney in order to trap the

warm air. Also putting on an additional warm layer of clothing during stops helps trap more

warm air before it has a chance to disappear. If you are still cold even with all your warm layers

on, generate your own heat by continually moving around. Do not sit on the ground as it will

drain heat from your body.

How too keep dry

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It is important to be aware of the loss of body fluids as a result of physical efforts. The body

always produces dampness in the form of perspiration. The moisture and dampness will beabsorbed by the clothing and will make you cold when the physical efforts is reduced. Adjust the

clothing in relation to temperature and work load. If there is a risk of becoming damp or wet

dress as economically as possible. Save the extra dry clothes for breaks (bivouac), and battle

pauses.

If your clothes have become damp or wet, put on dry clothes once drying of your wet clothes

can be guaranteed. The wet clothes should be dried in a heated room, tent, building etc. Damp

clothes can be dried using your body heat. Do so when performing light work. Use pockets

inside the field uniform to dry socks, mittens, insoles etc. Your clothes used as an outer layer

can also be freeze-dried. This is done by letting your clothes freeze to ice and then shake out

the ice. Use a small brush (Fig 4) clothes brush - to brush snow and ice from the uniform andequipment before entering a heated tent, building, vehicle etc. to avoid unnecessary dampness.

Fig 4

Closing remarks

Good and appropriate clothing is one of the main requirements in order to maintain combat

readiness of a unit, but it is also important that each soldier knows how to make proper use of

cold weather clothing in various conditions. I will close this article with some hints and tricks that

I consider as most important in the cold weather operation dress code.During activity and physical effort, dress as cold as you dare to prevent moisture from sweating.

Dress using the principle of the multilayer system, this will give you the best insulation as well

as the opportunity to select and adjust the combination according to the prevailing climate and

the intensity of the activity. Use fabrics of wool or a combination of wool and synthetic fibre as

inner layer, this will give you both insulation and move vapour away from the body.

It is just as important not to be too warm as it is not to be cold, try to sweat as little as possible.

Wear loose fitting clothes and ventilate dampness and vapour by using chimney ventilation.

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Close the chimney when resting.

Save your warm clothes until you rest and always have some warm clothes for this purpose. If

you know you are going to get wet, try to keep as much of your gear dry as possible.

Remember that half of the body's heat production escapes from an uncovered head and neck.

In other words, these parts of the body are extremely important when it comes to getting rid of

excess heat and retaining body heat.

If your feet are cold, cover your head!

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Cold Weather Operations Dress Code