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Exposure to Cold | |||||||||||
Effects on the body General information |
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 In severe low
temperatures action must be taken to protect the body and
its extremities. It is most important that minor injuries
be treated immediately to
avoid complications. Minor cuts and skin abrasions
provide a ready entry for frostbite.Skin contact with metal objects should be avoided. Contact with steel at temperatures of -7°C and lower will cause instant blistering. Feet should be protected from blisters, frostbite and 'immersion foot' -- a condition of painful swelling with inflammation and open lesions caused by prolonged exposure to low temperatures and moisture. Immersion foot may be avoided by keeping the feet warm and dry, which is also the only treatment possible should the complaint be contracted. When treating the feet they should not be rapidly rewarmed, and care should be taken to avoid damaging the skin or breaking blisters; they should not be massaged. 
FrostbiteLow temperatures causing freezing of the fluid in the tissues results in frostbite. Its initial stages are painless and may only be detected by a companion noticing the typical white patch on the skin or by the person affected feeling a hard spot on his face; the usual parts of the face affected are the nose, cheek bones, chin or ears. Such patches can easily be cured by warming them with the hand until the frozen fluid is melted, but it should be realised that it will only be a matter of time before the trouble will recur unless precautions such as using a hood or wind shield for the face are taken. Care should be taken not to let the hands get wet with petrol or oil. The feet are also liable to frostbite and this is more serious as they cannot be seen and the person affected will only be warned after a while by the lack of feeling; immediate action should be taken to restore the circulation. A frostbitten part should never be massaged or rubbed with snow.
Wind
Chill FactorI - Comfortable with normal precautions. II - Work becomes uncomfortable on overcast days unless properly clothed. III - Work becomes more hazardous even on clear days unless properly clothed. Heavy outer clothing is necessary. IV - Unprotected skin will freeze with direct, exposure over a prolonged period, depending on degree of activity, amount of solar radiation and state of skin and circulation. Heavy outer clothing becomes mandatory. V - Unprotected skin can freeze in 1 minute with direct exposure. Multiple layers of clothing are mandatory. Adequate face protection becomes important. Work alone is not advisable. VI - Adequate face protection becomes mandatory. Work alone must be prohibited and supervisors must control exposure time by careful scheduling. VII - Survival efforts are required. Personnel become easily fatigued, and mutual observations of companions is mandatory.
ClothingIf clothing gets wet in any way, or if hoar frost, which is almost invisible, settles on it, it should be dried as soon as possible. Perspiration should be avoided since it soaks into the clothing and ruins insulation qualities, as will any form of moisture. Before, starting arduous work, clothing should be removed or opened up so that work is commenced 'cold'. As the work progresses, clothing should be replaced or closed up until a comfortable body temperature is reached. Panting, and the intake of large masses of cold air, can lead to internal frostbite, and should therefore be avoided. Frequent rest between spells of labour and breathing only through the nose will help in this respect. A muffler or scarf worn across the lower part of the face will also be of value. Gloves should be worn continually, even for delicate jobs. They should always be worn on harness round the neck with a cross-piece to prevent loss.
Snow-blindnessUltra-violet light burning the cornea of the eye causes snow-blindness. The ultra-violet light reflected from snow and ice must be excluded from the eyes whenever the sun is above the horizon by wearing protective goggles or glasses. In emergency, effective substitute goggles can be made with cardboard or any other material cut into two ovals, with narrow horizontal eye-slits and held in position with string or cloth. Some protection may also be gained by blackening the face about the eyes, nose and cheeks with dirt, charcoal or soot. One can become snow-blind in overcast or cloudy conditions as easily as in direct sun since the ultra-violet light is always present; one attack predisposes to another. Symptoms appear some time after exposure when the eyes smart and water, and soon feel as though they are full of sand, and even blinking is painful. Severe pain will last at least 24 hours, and during this time it is best to remain in darkness, or keep the eyes bandaged.
HypothermiaUnder normal circumstances when wearing adequate protective clothing hypothermia, which is the term for an abnormally low body temperature, is unlikely to occur to a healthy individual. But in extreme conditions when exhaustion occurs, or when the insulative properties of clothing are impaired through tearing or wetting from sweat or water, or when the body is immobilised because of injury, hypothermia is quite likely to occur. lt may be recognised by an intense feeling of cold; abnormal behaviour patterns, unco-ordinated muscle movements which may result in stumbling and the like, culminating in unconsciousness and death. 
Treatment consists of removing the victims from the
hypothermia environment, ie shelter, remove wet clothing
and replace with dry, wrap in blankets to insulate from
the cold, and provide some extra heat for the body. If
conscious, give plenty of hot sweet drinks and food if
possible. Victims are very likely to suffer relapses
unless special precautions are taken. |
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Immersion General information |
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In polar waters the dangers of immersion experienced elsewhere are accentuated by the colder water. Without special clothing such as immersion suits, even short periods of immersion in extremely cold water can be fatal. Arrangements for abandoning ship should make provision therefore for entry into lifeboats or liferafts by scrambling nets or other means without entering the water. The clothing worn, morale, physical fitness, injury or loss of body heat at the time of immersion may to cause wide variations in the times of survival from unconsciousness or from death. For further details see, A Pocket Guide to Cold Water Survival, published by IMO. Approximate likely times of survival of those immersed in light clothing are as follows:
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