The following information has been reproduced with permission from the book
‘Rural Living Manual’, 2nd Edition by author Bernie Webb.
RURAL-Fire-Breaks.pdf (PDF 597KB)
Firebreaks (Fire Access Trails)
All existing properties and practically all new subdivisions should have some form of firebreak already installed. However, there is a good chance that it will be inadequate or barely meet the regulations. The minimum Firebreak Regulations you should comply with are contained in the ‘Fire Notice’ (or its equivalent) applicable to your local area and must be completed before the ‘due by date’ (usually around the 31st of November). Read ‘Bushfires’ in conjunction with this chapter.
The term ’firebreak’ often conjures up a false sense of security. A firebreak in the path of a fire will not necessarily stop the fire dead in its tracks, in fact it probably won’t. Depending on wind conditions, temperature, fuel load and the state of the firebreak, there is a good chance that the fire will jump straight across the firebreak at one or more locations. Conversely a firebreak will, under most circumstances, stop a fire burning back into the wind and is arguably one of a firebreak’s most useful attributes. A firebreak can also provide a relatively safe edge from which to conduct a back burn. Fire fighters will often let a fire burn back into the wind and up to a firebreak where the fire will usually extinguish itself.
Fire Access Trails – ‘4×4 rule’
Probably the most useful role of a firebreak is to allow a 4WD Fire Fighting Unit to be able to drive safely around the property and thus gain access to anything that is burning. Perhaps fireb reaks would be better identified if they were referred to as ‘Fire Access Trails’. This term better describes their use and does not conjure up the false sense of security mentioned above. In reality this means any 4WD vehicle should be able to traverse along a firebreak without anything touching it on the sides or from above. Therefore, I recommend all your firebreaks be at least 4m in width and 4m in height, I like to call it, the ‘4×4 rule’ (In several shires, 4 m wide by 4 m high, is already the minimum standard). One way to test this is to drive a 4WD or tractor around the firebreak ensuring that there is easy access and that there are no overhanging branches.
A good friend of mine has developed a far more accurate way to verify that your firebreaks conform to the ‘4×4 rule’. Simply grab a 4 m length of 25 mm orange[1] conduit; available in most hardware stores for less than $10. Holding the conduit horizontal, walk completely around all your firebreaks. You should be able to achieve this without touching the fence to one side or any bush or trees to the other side. As required, swing the conduit into a vertical position to check that all overhead tree branches are pruned above the 4m height limit. While you are at it, do the same on your driveway, which should also comply with the ‘4×4 rule’ (particularly if you would like fire fighting vehicles defending your house from a fire!). A good time to comply with the ‘4×4 rule’ and/or the local ‘Fire Notice’, is in the relatively cooler months of early spring before the beginning of the bushfire season and before you employ a contractor to rotary hoe or plough them.
Under no circumstances should there be any ‘dead ends’ in a firebreak. In a fire situation with disorientating heat and smoke all around, a ‘dead end’ could be potentially deadly to fire crews, who are having to reverse out with limited visibility, prolonging their time in the potential danger zone of the fire. There should always be a means of escape such as a turnaround area or gate.
If you have or are going to divide your property up into smaller paddocks, please ensure you have either a real gate or at least a ‘cocky gate’[2] where any internal fence butts into the external boundary fence (crosses a firebreak). This is to ensure a fire fighting vehicle can easily and safely traverse right around your property without unnecessary hindrance. In a bushfire situation (depending on what stock you may or may not have) it is a good idea to open ALL gates to facilitate the movement of fire fighting vehicles.
Clear firebreak to mineral earth
As well as a firebreak complying with the ‘4×4 rule’ to be trafficable, it must also be cleared to mineral or bare earth with all combustible material removed so that it is incapable of burning. This is usually achieved by hiring a contractor with a tractor and suitable attachment, to rotary hoe or plough your firebreaks. Please be aware most ‘firebreak contractors’ will only rotary hoe or plough the firebreaks (usually at a predetermined cost) and will not prune back the firebreaks to comply with the ‘4×4 rule’ unless specifically asked to do so and at an additional expense.
Ideally all firebreaks should be run straight along and adjacent to the boundary fence line. Where possible large trees should be protected and sometimes this means they are in the way of a firebreak. If this is the case it may be possible to construct the firebreak to go around the tree and veer back to the fence line, maintaining the ‘4×4 rule’. In these circumstances it is also advisable to keep the area of ground between the fence line and the detoured firebreak clear, by removing with hand tools, all fuel (dead bush, grass etc.), to assist in the protection of the fence.
Firebreaks MUST be maintained throughout the Fire Season
A firebreak must comply with the ‘4×4 rule’ and/or the local ‘Fire Notice’, remaining free of any combustible material throughout the entire fire season. Due to the steady and relentless growth of the understory[3] towards the light, additional pruning or clearing of combustible material may be required at any time to achieve this.
Neighbours Firebreaks
As your neighbour’s firebreaks are adjacent to your property, it is equally important that they have good quality and compliant firebreaks. If they are not up to scratch it is very much in your interest to have a conversation with them; don’t just rely on the Council Rangers picking up the deficiency when they check firebreaks at the beginning of the season. IF they do pick up the problem, by the time it is rectified, it is well and truly in the fire season (mid-January) and may be too late!
If your neighbour’s firebreak IS up to standard, immediately adjacent to the other side of your boundary fence and you keep the fence line clear of all trees, shrubs, grass and leaves, you have effectively doubled the width of firebreak to 8 m and protected the fence (see Figure 1).
[1] Orange conduit has a thicker wall and is more ridged than grey conduit (and looks better in the photos!)
[2] A ‘cocky gate’ is a length of wire (same as fence) stretched across the ‘gateway’ with, preferably, a quick disconnect system.
[3] The plants growing at the lower level (saplings, seedlings, shrubs, bushes etc.) under the main canopy.
