Radiant Heat - the killer in a bushfire

Radiant heat can kill. You need to cover up - dress to protect yourself - take refuge from direct heat.

Every summer, people try to survive bushfires by wearing light summer dresses, shorts, singlets, even swimsuits. They usually die without the flames even touching their exposed skin. They don't understand the real risks of bushfire - heat stroke, dehydration even asphyxiation.

Radiant heat cannot transmit through solid objects

If you put your hand near an open flame, an electric heater element or electric light bulb, you can feel the radiant heat it generates. Draw your hand away and the amount of heat on your skin decreases.

Put something between your skin and the heat source, and again, your skin immediately feels 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. It kills animals caught in the open. People can 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 heart failure.

Shield yourself from radiant heat

Bushfires usually occur on days of high temperature. You and your family may be in shorts or swimsuits and bare feet and sandals.

Remember, the deadly effects of radiant heat are increased by the amount of skin exposed to it. So as soon as you know there are bushfires in your area, cover up!

Firefighters wear protective gear to survive. So should you. Some personal protective clothing is general purpose and you may already have it.

Put on natural fibre long pants and light long-sleeved wool jumpers or close weave cotton shirts or overalls. Wear good solid footwear - preferably leather and a sturdy hat.

Organise a fire cupboard or box at the beginning of the fire season and pack it with clothing for all members of the family.

Take cover inside your house

As the fire front passes, radiant heat levels become extreme.  Your clothing will not be sufficient to protect you for the five to 20 minutes it may take for the fire to pass.

Radiant heat cannot penetrate through solid objects, but will pass through glass. That means your best protection is a well-prepared house.

As the fire front passes, stay inside with doors and windows shut to protect against spark entry. Remember, if you flee from your house, you lose its protection against radiant heat.

Other structures such as brick walls can offer protection. Taking shelter in pools, dams and water tanks is not a safe option. The air above the water will be dangerous to breathe, and may be deadly when inhaled.

Reduce the risk of dehydration

Dehydration occurs when fluid output from the body is greater than fluid input. It is dangerous because it creates a build up of salts and minerals in the body tissues which put strain on the kidneys. When the kidneys fail, death can quickly follow.

The high air temperature during a bushfire and the added stress of wearing extra clothing to shield against radiant heat will contribute to make you sweat heavily.

The fluids you lose must be replaced continuously or you risk dehydration. Keep cool, drink water often.

Drink cool fluids at every opportunity - even if you don't feel thirsty. Drink often to replace the fluids you sweat off. Alcohol and fizzy drinks must be avoided as they aid dehydration.

Children and the elderly are especially vulnerable, so pay extra attention to their needs. Keep them indoors where they do not need to wear heavy protective clothing for long periods. Cool the skin by sponging with cold water. Make sure they drink frequently.

If caught on the road

Remember, if your plan is to leave when a fire is burning in your area, do so before the fire threatens and road travel becomes dangerous. Late evacuation is a deadly option. High fire risk days, should be your trigger to put your plan into action.

Always u-turn to safety if you have the option, but if you are caught on the road, your car offers the best protection from radiant heat as the fire front passes. Do not get out and run.

• Pull over to the side of the road into a clear area –a dirt track or road is the best
• Try not to park the car in a place where it is surrounded by fuel for the fire - long dry grass and scrub for example
• Park the car behind a solid object like a brick toilet block or a solid brick or concrete bus shelter to protect the car against radiant heat.
• Ensure all windows and doors are tightly closed
• Shut all air vents and turn air conditioning off
• Put the hazard lights and headlights on and keep the engine running
• Cover exposed skin as much as possible with clothing – not synthetic
• Get down as low as possible below window level and cover up with a woollen blanket until the fire front passes. You will feel a reduction in the heat and then it is time to get out of the car and move to safety. If travelling in the country, always carry a woollen blanket in your car for this purpose
• Remember to drink lots of water to stop yourself from dehydrating