I am a member of Australian Geographic and Australian Geographic recently prepared an excellent article on the following:-
a) Bushfire management.
b) How to prepare a home for Ember attack during a bushfire.
With simple and superb diagrams. More importantly the article addresses issues of ember attack based upon the concept of "The weakest Link" . It addresses the defences available.
Australian Geographic - July to September 2008 Edition. Titled - Fire Alarm
- Edition 91, Pages 58 to 69.
Suitable websites provided include:-www.bushfirecrc.com
(For bushfire knowledge and study)www.australiangeographic.com.au
With 750 homes lost in the Victorian bushfires, Australian Geographic looks at Ember attack during a bushfire and survival for a home and residents specific to Ember Attacks including:-Roof - Top entry
In a bushfire, most houses can survive the initial blast of the fire front but burn down later from the inside out from embers getting inside (CSIRO Fire Researcher, Justin Leonard).
Embers can get into roofs via gaps under roof tiles. A layer of boarding under the tiles can reduce the incidence of embers but it must not have holes from work or repairs.Sheds and garden accessories
A timber garden shed should not be closer than 12 metres from a house. A steel shed with no windows will not emit as much flame and radiation even if the contents catch fire. A steel garden shed may be appropriate.Garbage bins
Placing plastic wheelie bins close to a home during a fire is inappropriate.Garden beds
Placing garden beds near a home is a risk. These can catch fire and considered inappropriate planning for bushfire preparation.Fences
Steel fences are more appropriate rather than fences constructed of timber.Gutter plugs
Buy gutter plugs and keep them handy so gutters can fill with water when required. Gutters should not be allowed to fill with litter.Flames trees
Some trees near a home can help to prevent houses burning down by reducing the heat hitting a house. Species influences combustibility. Pines and Eucalyptus trees are inappropriate species. This requires expert advice from a local nursery.What goes up
Air vents, toilet flues and chimneys are weak links unless gaps of 2 mm are screened with metal flywire to keep out embers.Parking cars
Motor cars should be parked 10 or more metres from homes. A car parked too close to a home will cause heat radiation that can ignite the house. A car should be safe in a garage that is ember proof. Unfortunately most garages have too many holes that allows embers to get in.Windows
Windows left open allows embers to get in. Flyscreens should be fitted to windows to keep embers out and windows closed.Door entrances
The front door mat can catch alight and wind can blow the flames or embers inside.Storage
Any under floor storage should be totally sealed and even boxed off preventing leaves and rubbish from accumulating here. Without 2 mm metal mesh screens, embers may still get through the gaps, setting fire to anything flammable.
A safe house is critical in bushfire prone areas and a house that follows the safety guidelines does stand a better chance of surviving an ember attack.
The problem for so many houses is that it seems people are well prepared but "The Weakest Link" principal is not well thought out. One can have the perfect house and design but if there is just one thing wrong, the risk of a house burning down is greatly increased.
Apparently an assessment system is being trialed by the CSIRO that should be implemented soon that gives a person a probability of loss of a home based on "The Weakest Link" approach. The owners can choose to knock factors off. A score of zero may not be appropriate as that entails someone living in a concrete bunker.
However, there are 2 critical tips for those living in bushfire prone areas being:-
Screen any gap of more than 2 mm.
Install appropriate flyscreens on windows to close the gaps.
The websites and links to this article is provided above.