The term "subdivision" is defined in the Environmental Planning and Assessment Act 1997 as the division of land into two or more parts that, after the division, would be obviously adapted for separate occupation, use or disposition (see Dictionary for full definition). Strata subdivision, community title and boundary adjustment are also considered subdivision.
Subdivision of land for a residential or rural-residential purpose is the subdivision of any land on which the zoning permits the construction of a Class 1, 2, 3 or 4 building under the Building Code of Australia. For example, many industrial and commercial subdivisions permit a residential house (caretaker's residence) to be constructed. Such subdivisions are considered residential and should be assessed accordingly.
The consolidation of two or more lots into one is not defined as subdivision and is not captured under section 100B of the Rural Fires Act 1997 as requiring a Bush Fire Safety Authority (BFSA).
- Residential Subdivision
Residential subdivision can consist of large to medium scale "releases" of land for extension of urban areas or smaller scale "local" subdivision and is usually associated with single dwelling houses - though zoning may permit dual occupancy and multi-unit developments. Development consent is required from the council for subdivision and a BFSA is required from the NSW RFS. Development consent, or a Complying Development Certificate, is then required for individual dwellings.
In new subdivisions an appropriate combination of BPMs, especially an APZ, should be provided.
- Rural-Residential Subdivision
Rural-residential developments include blocks often associated with lifestyle choices rather than focusing on some form of primary production. Where agricultural pursuits are undertaken they are considered secondary to the residential component of the use of the land.
Consideration should be given, where practical, to grouping of rural-residential buildings into clusters which allow for the establishment of APZs around a group of dwellings rather than having to ensure individual protection for a large number of scattered dwellings. The clustering of dwellings provides for better protection with reduced vegetation clearance and hence less environmental impact.
- Isolated Rural Developments
Subdivision for the creation of isolated rural developments, particularly in rugged, heavily timbered country, poses additional problems in the provision of adequate levels of protection from bush fires. Where developments are located in these areas, occupants and fire-fighters may have to travel large distances through bush fire prone vegetation when accessing or evacuating a property. In addition, the isolation means that the response times of the local fire fighting authority may be longer, should the property be impacted by fire.
The major issues for isolated rural developments arise from the need to protect fire fighters as well as residents in less accessible areas. As a result greater emphasis is placed on:
- the provision of safe access/egress to the property so occupants leaving, and fire-fighters/rescuers accessing the property, can do so in relative safety;
- the provision of adequate APZs to create an area where occupants and fire-fighters remaining on site will have a good chance of survival;
- and water supplies and fire protection systems such as spray systems. In such cases dedicated water supplies may exceed standard requirements.
To achieve the required level of protection, dedicated static water supplies will need to be extended beyond the specification recommended in this document. This requirement will need to be determined based on the extent of the hazard faced and the isolation and access arrangements of the development.
Travel distances of 200 metres or more are particularly problematic in that it is difficult to traverse with dense smoke and reduced vision as well as the increased chance of being isolated by the advancing fire. Trees close to the access track become obstacles in the hazy environment. For these reasons, where access is greater than 200 metres from a main road or refuge suitable for occupants and fire-fighters, a secondary access in a different direction from the main property access road should be provided. Where site circumstances do not allow for an effective alternative access, a greater emphasis is placed on other protection measures e.g. increased water supply and on-site fire fighting equipment.
The performance criteria and acceptable solutions for subdivisions can be found in Section 4.1.3 of Chapter 4 - Performance Based Controls.