Asset Protection Zones which are managed progressively minimise the fuel loads and reduce the threat to buildings
The Asset Protection Zones help to lower the radiant heat levels to be at an acceptable level.
Asset Protection Zones Development on bush fire prone land will usually entail the implementation of an asset protection zone often referred to as APZ. The Asset Protection Zones allows for a buffer zone between the building and any bushfire danger, this allows for the radiant heat levels to be at an acceptable level. The required size of any APZ will vary by your bushfire attack level (BAL).All asset protection zones should have a goal of lowering the radiant heat levels to a minimum of 29kW/m² (BAL-29). BAL rating are calculated once the distance from the vegetation and the slope under that vegetation are known. Using the fire danger index (FDI) you will know the correct construction level for any building.
The site assessment methodology is set out in AS3959-2009 (Construction of buildings in bushfire-prone areas) Asset Protection Zones which are managed progressively minimise the fuel loads and reduce the threat to buildings, APZ contain an area of maintained fuel loads. Roads, parks and fire trials are a few of the items that can be placed between a building and the hazard. APZ can include a defendable space (The width of the defendable space should be a minimum of 3 metres) for firefighting that can be carried out to protect the construction and significantly decrease the heat threat at the building surface. Ideally any APZ should be located wholly within the development or property but apz can use excluded and low threat vegetation that is adjacent to the lot this will allow reduced dimensions of the APZ within the lot.
Within the APZ all vegetation should be kept to a complete minimum, the area should be free from all flammable or explosive items and obstructions. APZ can contain footpaths public roads buildings rocky outcrops golf courses maintained parkland waterways as well as cultivated gardens. Cultivated gardens are the most common item to be used for a APZ for single dwellings, they will contain maintained lawns (grasses cut under 100mm in height) This will need to be enforced by local fire break notices.
Fences: within the APZ are constructed from non-combustible materials (e.g. iron, brick, limestone, metal post and wire). Fine Fuel load: combustible dead vegetation should be removed. Trees (> 5 metres in height):A minimum of 6 metres from buildings , remove lower branches, canopy cover should be less than 15% with tree canopies at minimum of 5 metres apart as to not form a continuous canopy The understory vegetation should be removed.
For a distance of 30m around your building all grasses are to be maintain at a height no more than 100mm. The understory should be removed and any remaining trees should have no more than 15% canopy cover. The remaining trees should be a minimum of 5 metres apart and not be continuous.
All fences should be non-combustible and all dead vegetation should be cleared (including dead leaves)