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The Concept of Shelters

The concept of shelters comes from the fact that there is no alternative which is better. The designer of the ‘Little Beauty’ bushfire shelter likened the situation to the blitz of London in the second world war, ‘a danger that comes rapidly from an uncertain direction to an indefinite destination’ for one could never know if the bombs would fall or into which street, so shelters were the only real answer for safety apart from moving from the area. Both of these answers were used during the blitz , but one’s life is built around one’s home, so this was not always feasible so usually it was the children who were evacuated. However the dangers are somewhat different, a bomb differs from bushfire so each must be designed for it’s purpose.

As has been shown the term ‘bushfire’ is a generalised term to cover all situations , however conditions will differ dependent upon the various factors involved and shown elsewhere on this site, as a general rule it would be wise to allow for the worst conditions. There many rumours and information which may give a false sense of security and remaining behind to face an unknown quantity may not be sensible. Likewise evacuation is extremely hazardous, a simple thing such as a tree branch on the road may cost life.

The Design of the ‘Little Beauty’ bushfire shelter

When designing for safety one must consider which dangers are present and we must allow for the worst situation, it is no use saying it will never happen. In considering bushfire there is much false information and little has been proved. For example the purpose of the second fire test on the shelter was to find out whether a frequently heard story , that houses exploded , was in fact possible. Most ‘experts’ said that it didn’t happen, so when a most stable man from the fires related how he was sitting on his earthmover waiting to clear a fire break and watching three houses in front of him, “ When suddenly the centre one exploded. Just went up !” It was time to act. An hypothesis was formed as to how it could happen . Every hypothesis has to be proved and the second test did just that, proved that the exploding house was a possibility.

So, with all the various information most of which was unproven or unreliable, it was decided that one way to produce safety in a shelter would be to provide a separate atmosphere to the external. This is what the ‘Little Beauty’ shelter is, it is not a bunker as so many ‘experts’ mistakenly refer to it, it is a separate atmosphere to the external. The problem was ‘ How to connect the two atmospheres so that one can pass from one to the other ?’

This then becomes the design – A primary chamber which is the separate atmosphere and the external which is the outside atmosphere ,these are linked by a secondary chamber which uses the air from the primary chamber to clean and protect both the primary and secondary chambers by discharging the air from the primary chamber through the secondary chamber to the external. Which gives when operating ‘ a constant discharge of air to the external and a cooling of air inside the shelter.

Or technically :- an adiabatic principle and differential pressure principle taken from the ‘gas laws’ in physics.

There are other factors involved such as gale force firestorms and radiant heat. Temperatures in the region of fifteen hundred degrees have been measured which is around the melting point of steel and when one sees the glass of windows melted to droplets in the fires, even though the house and frames were still standing , one begins to understand. Likewise heat has been shown to penetrate up to four hundred millimetres below the surface which had to be a consideration. It was decided that if placed below ground, a shelter would not only be scarcely visible, which would make it more acceptable but it was a way of overcoming the radiant heat factor.

The Function of the ‘Little Beauty’ shelter

How does the shelter emit a constant flow of air ?

This is done by the use of compressed air which is contained in gas cylinders under the seats. By the simple movement of a lever the function commences. This movement discharges a constant and carefully regulated air supply to the primary chamber, this can be doubled simply by pushing the lever in the opposite direction , as when there are extra persons present. This air supply is then directed through the secondary chamber to the external. (It is envisaged that the supply of air and loading of the cylinders may be undertaken by the local volunteer fire organisation for which a small charge could be made ) Otherwise cylinders are obtainable from the nearest gas supply depot at a very reasonable cost and hired for the season rather than purchased.

A frequently asked question, “Why not use oxygen ?”

Oxygen promotes combustion and is unsafe. Air is perfectly safe, however the cylinders are rather heavy and cumbersome and careful loading is necessary. It is also wise to protect the primary chamber floor when loading. There are half and full size cylinders available, with space under the seats for four half size or two full size. The amount of air required will depend on the number of persons present. It is a family shelter and one full size cylinder would be sufficient. (Assuming two adults three children) This would last almost two hours if continually on , however it is used with intermittent opening of external door to check the fire in which case it may be used very little as the function is only necessary when fire is at the entrance. When the external door is open the air may be off. It is also better to sit quietly and breathe slowly as this consumes less air.

Operation of the Shelter

At the first hint of fire be it near or far away, get the family into the shelter, at this point the family is completely safe. The person in charge sits at the opening legs inside the secondary chamber, feet on top rung of ladder and watches fire.  If fire strikes the property they descend and close the door to approximately seventy five millimetre. That is with the handle resting on top of the catch, they then watch the fire through the opening, if it strikes the entrance the external door is closed, the secondary chamber door is closed, the function operated. At any time the procedure may be reversed to check fire.

Testing of the Shelter

As has been said before the ‘Little Beauty’ shelter is not a bunker it is a patented invention, therefore it would not have regulations applying to it because it is based on new thought, this is what a patent is ‘ that which furthers the state of the art’ however, an invention is based on an hypothesis and every hypothesis must be proved and if an inventor claims to have an invention which will save lives, then it is only fair that they should be the first one to test it.

This was the purpose of the first test, but how do we assess the quantity of risk involved in bushfire when there is so much rumour and false information ?

It was decided to test by actually exceeding the worst possible conditions. We would expose the shelter to a greater risk than that involved in bushfire to test the hypothesis. It would be tested by a huge fire actually covering the shelter with the inventor inside.

A site was found and the test model installed with the assistance of some fine people at the Knox agricultural institute. A fire was prepared which would give a tremendous heat, twenty truck loads of bush material ; forty inner tubes ; twenty car tyres interspersed ; inner tubes and forty gallons of diesel and petrol thrown onto the fire and entrance once the fire was in progress.

The testing of the ‘Little Beauty’ shelter function was a complete success !

Says the shelter designer, “ I had the confidence of my design, but those who volunteered to be in the shelter for the testing were fine brave people who put their lives on the line that others might be safe. ”

Mike Lyons…………( independent test chemist)

Mike Edmunds………(journalist)

Jo Pearson…………..(2^nd.fire test, journalist)

Pam Dauncey……….(Nurse,… Girl Friday who struggled me to meetings, dug wet clay at 5.30 am in the morning , who was on the doorstep of hire companies waiting for them to open, was communication safety contact for both fire tests, who supported me physically and sometimes financially through the long hours)

“With tears of humility, I salute them.”

~ ~ ~

These fine people are the role models for our society, I could not have succeeded without them ! (Ray Toyne, designer)

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