Personal Survival
Courtesy of the Government of South Australia and the CFS Country Fire Service
www.cfs.sa.gov.au
Protect from Radiant Heat:
Radiant heat is the major cause of death during bushfires. If you put your hand near an open flame, an electric heater or light bulb you can feel the radiant heat it generates. Draw your hand away and the amount of heat you feel on your skin decreases. Put something between your skin and the heat source and again your skin feels immediately cooler. That´s all you need to remember about radiant heat from bushfires - distance and shielding protect you from dangerous exposure.
The danger is real. Radiant heat from the flame front of a bushfire scorches vegetation well in front of its path and kills animals caught in the open. People also die if they do not seek protection. Death is caused by heat stroke, when the body´s cooling system fails, leading to heat exhaustion and death.
To Manage Radiant Heat:
- decrease fire intensity by reducing fine fuels around your home prior to the fire danger season,
- move away from the heat source, and
- establish a barrier between the heat source and yourself, for example: - a solid wall
- another building
- protective clothing
- blankets
- landscaping features such as embankments and terracing etc.
How People Die in Bushfires:
Heat Stress
The human body operates most efficiently between a narrow range of temperatures. Once it exceeds the uppermost limits, physiological failure begins and this can lead to collapse and death.
Heat stress can be managed by:
- Wearing sensible clothing: clothes of natural fibre that allow air flow and are not too hot.
- Drinking lots of water.
- Sheltering from radiant heat as much as possible, especially when the fire front arrives.
- Avoiding unnecessary exertion.
- Avoiding elevated water tanks. Once immersed in water, the body will quickly absorb heat from the water. If the ambient air temperature is in the high thirties and a bushfire raises the temperature of the water a further ten degrees, the water/body temperature will be unsurvivable.
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Dehydration
Very hot conditions plus excessive stress and exertion during bushfires will rapidly lead to loss of fluids and subsequent dehydration. In a bushfire situation a person could lose up to 2 litres/hour. Symptoms of dehydration, such as tiredness, irritability, irrational behaviour, loss of coordination, may lead to collapse and in extreme cases death.
Dehydration can be managed by regularly drinking water, about 1 cup every 5 to 10 minutes. It is easier to manage where there is more than one person present so that one can look after the other.
Burn Injuries
Burn injuries occur when a body is exposed to intense heat and can be managed by avoiding being in the wrong place at the wrong time. This requires understanding and planning.
Physical Injuries
Bushfire events are conducive to accidents because of factors such as poor visibility, high stress and adrenalin levels. This leads to confusion, poor decision making, loss of concentration and tunnel vision.
The risk of physical injuries can be managed by being extra careful. People should be aware of the likelihood of injury whilst carrying out fire protection/suppression activities. Good planning is also important in preventing physical injuries. Good planning leads to confidence, which reduces stress levels. Good planning also means less stressful decisions need to be made on the spot and is conducive to more controlled behaviour.
Lung Injuries
In a building fire the most common hazard to humans is from smoke and toxic gases. Death often results from oxygen deprivation in the bloodstream, caused by the replacement of oxygen in the hemoglobin by carbon monoxide. While this is a major cause of death in house fires it is uncommon in bushfires. In bushfires smoke contributes indirectly to death by obscuring visibility, irritating the eyes and lungs and causing stress.
Lung injuries can be managed by protecting the lungs from smoke and super heated air. It is important to seek shelter when heat and smoke are most intense. Nose and mouth should be covered with a dust mask, wet towel or scarf etc. A special filter mask for people suffering with respiratory conditions such as asthma should be included in your survival kit.
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