Will your House Survive a Bushfire ?

This calculator is based solely on research into house losses that occurred during the 1983 Ash Wednesday fire at Mount Macedon, Victoria. It is for houses exposed to a forest fire which is driven by strong winds on a very hot day i.e. extreme fire weather conditions. In a forest, assume the calculator maybe in error by +or- 15%. In grassland or other fuel types it should be useful but less accurate.

FIRST - ENTER THE COEFFICENTS IN APPROPRIATE BOXES
Forest Fire Danger Index (0 - 100) Fuel Load (Tonnes/Hectare) Ground Slope (°)

### Now Check the Appropriate Boxes

Persons in attendance
Absence of nearby flammable object or structure
Roof not wooden
Roof is tiled or has a pitch of less than 10 degrees
External walls brick (includes brick-veneer), stone or cement
Absence of trees greater than 5 metres within 2- 40 metres of the house

CALCULATED HOUSE SURVIVAL PROBABILITY
%

### Fire Intensity

Is the most important factor which determines house survival. Intensity can be reduced by decreasing the available FUEL on the ground within at least 40 metres of the house.

### Trees

Near a house they increase the hazard by a small amount, if however the fuel load on the ground is reduced then trees can be retained.

To measure fuel load measure a 1 metre by 1 metre square on the ground. Collect all the dead fuel that is thinner than a pencil and weigh it. Divide this weight by 100 and you have the fuel load in tonnes/hectare.

For accurate results obtain several samples around the house and average the values.

### Attendance

During a fire it is important for house survival. Well prepared people who stay at a properly prepared house throughout a fire can extinguish small fires and thereby stop a house from burning down. Evacuations just before a fire arrives are risky. A house or similar building is usually the safest refuge during a fire since it will protect you from the radiant heat of the fire.

From:

• Assessing the bushfire hazard of houses: a quantitative approach. A.A.G. Wilson (1984) Technical Paper No. 6, National Centre of Rural Fire Research.
• Fight or Flee? - a case study of the Mount Macedon bushfire. A.A.G. Wilson and I.S. Ferguson (1984). Australian Forestry Vol. 47.
• Predicting the probarbility of house survival during bushfires. A.A.G. Wilson and I.S. Ferguson (1986). Journal of Environmental Management Vol. 23.

This meter was made available by Firebreak, with thanks.