Background information for teachers
The following information is designed to provide teachers with a summary of the key issues relating to bush fires, bush fire preparation and safety and the knowledge to teach these concepts. Much of the information relates to preparing homes and keeping families safe, but as a teacher, you are also responsible for the safety of the children in your care if a fire occurs, or is likely, in the area around your school. Many of the preparation tips can be applied to school buildings and grounds as well as residential properties. For details specific to your area contact the NSW Rural Fire Service.
Understanding bush fires
A bush fire is a fire that burns in grass, bush, scrub or woodland. They can threaten property, people, animals and the environment. It is important to understand how they can start, what factors make them more dangerous, and how to be prepared in the event of a bush fire.
A bush fire, like any fire, is a chemical reaction that needs three things to burn: oxygen, fuel and heat.
- We all need oxygen to survive, and so do fires.
- Anything that will burn provides fuel, which feeds fire. Keeping fuel away from your home (e.g. keeping your gutters free of leaves, trimming grass and storing piles of wood and gas bottles away from the home), is helpful in keeping your home safe from bush fires.
- The final element, heat, is required to ignite (set fire to) the fuel. Most bush fires get heat from things such as lightning, matches, or electricity.
Bush fires can start at any time, but are more dangerous and harder to control in particular areas and at certain times of the year. During ‘Fire Danger Season’ (can also be known as ‘Bush fire Season’ or ‘Bush Fire Danger Season’), restrictions are placed on certain activities to help reduce the risk of bush fires. Rural areas are divided into ‘fire ban districts’. These districts are areas where fire dangers are similar enough so that one set of fire ban rules apply to a large area. Some days are declared ‘total fire ban’ days due to a combination of factors that increase bush fire risks. On these days, camp fires must not be lit, some types of BBQ’s must not be used, and welding equipment or anything that could create a spark is also prohibited from being used.
For information about whether today is a ‘Total Fire Ban’ day or for other fire restrictions visit the NSW Rural Fire Service website.
You could also watch the ‘Total Fire Ban’ video which has more information about ‘Total Fire Bans’.
Bush fires vary in intensity. A more intense bush fire will generate more heat, may be harder to control and cause more damage than a smaller or less intense fire. Fire intensity depends on three main factors: vegetation, weather and topography.
- Vegetation can affect the heat and speed of a bush fire. A bush fire in a forest filled with heavy undergrowth will be very hot, yet may not move quickly, whereas a fire in grassland may be less intense but will burn very quickly. Bush fires in coastal scrub burn very hot, yet do not move as fast as a grass fire.
- Weather conditions such as extreme heat, low humidity, gusting winds and low rainfall dramatically increase a bush fire’s intensity and the rate at which it spreads.
- Topography can affect the speed and intensity of a bush fire. Fires burn more quickly and with greater intensity up slopes than they do on flat ground or downhill.
How a bush fire spreads
Bush fires spread in three ways: direct flame contact, radiant heat and burning embers.
- Direct flame contact – flames touch unburnt fuels and raises their temperature to ignition. This process is hastened by wind blowing the flames deeper into the fuel ahead or an upward slope presenting fuel to the flames sooner.
- Radiant heat – radiant heat from the fire raises adjacent fuel to ignition temperature, often before the flames reach it.
- Burning embers – embers are burning leaves and twigs which are carried by the wind. When embers land on fine fuels they can start small fires. If left unchecked, these fires smoulder, grow and spread. Embers are carried ahead of the actual fire (can be up to 30km ahead) by wind and can land on flammable material, causing small fires to start. An ‘ember attack’ is the main cause of house loss in bush fires as they can occur before, during and after the fire front passes.