Part G5 Construction in bushfire prone areas

The Objective of this Part is to—

1. safeguard occupants from injury from the effects of a bushfire; and
2. protect buildings from the effects of a bushfire; and
3. facilitate temporary shelter for building occupants who may be unable to readily evacuate the building prior to a bushfire.

A building constructed in a designated bushfire prone area—

1. is to provide a resistance to bushfires in order to reduce the danger to life and minimise the risk of the loss of the building; and
2. if occupied by people who may be unable to readily evacuate the building prior to a bushfire, is to be constructed so as to provide its occupants shelter from the direct and indirect actions of a bushfire.

A building that is constructed in a designated bushfire prone area must be designed and constructed to—

1. reduce the risk of ignition from a design bushfire with an annual exceedance probability not more than 1:100 years, or 1:200 years for a Class 9 building; and
2. take account of the assessed duration and intensity of the fire actions of the design bushfire; and
3. be designed to prevent internal ignition of the building and its contents; and
4. maintain the structural integrity of the building for the duration of the design bushfire.

A building that is constructed in a designated bushfire prone area and occupied by people who may be unable to readily evacuate the building prior to a bushfire must, to the degree necessary—

1. reduce the risk of an untenable indoor environment for occupants during a bushfire event, appropriate to the—
   1. location of the building relative to fire hazards, including—
      1. classified vegetation; and
      2. adjacent buildings, structures and movable objects; and
      3. carparking areas and allotment boundaries; and
      4. other combustible materials; and
   2. number of occupants to be accommodated within the building; and
   3. intensity of bushfire attack on the building; and
   4. duration of occupancy; and
   5. intensity of potential consequential fires; and
   6. occupant tenability within the building before, during and after the bushfire event; and
   7. combined effects of structural, fire exposure and other effects to which the building may reasonably be subjected; and
   8. provision of fire fighting equipment and water supply to facilitate protection of the building; and
2. be provided with vehicular access to the site to enable firefighting and emergency personnel to defend or evacuate the building; and
3. have access to a sufficient supply of water for firefighting purposes on the site; and
4. provide safe access within the site to the building (including carparking areas), as well as safe egress after the bushfire event.

(1) Compliance with Performance Requirement G5P1 is verified if the ignition probability for a building exposed to a design bushfire does not exceed 10%.

(2) Bushfire design actions must be determined in consideration of the annual probability of a design bushfire derived from—

1. assigning the building or structure with an Importance Level in accordance with (3); and
2. determining the corresponding annual probability of exceedance in accordance with Table G5V1.

(3) A building or structure's Importance Level must be identified as one of the following:

1. Importance Level 1 — where the building or structure presents a low degree of hazard to life and other property in the case of failure.
2. Importance Level 2 — where the building or structure is not of Importance Level 1, 3 or 4 or is a Class 2 building accommodating 12 people or less.
3. Importance Level 3 — where the building is designed to contain a large number of people and is a—
   1. Class 2 building accommodating more than 12 people; or
   2. Class 3 boarding house, guest house, hostel, lodging house or backpackers accommodation; or
   3. Class 3 residential part of a hotel or motel; or
   4. Class 3 residential part of a school.
4. Importance Level 4 — where the building or structure is—
   1. essential to emergency management or post-disaster recovery; or
   2. associated with hazardous facilities; or
   3. subject to a necessary ‘defend in place’ strategy and is a—
      1. Class 3 accommodation building for the aged, children or people with disabilities; or
      2. Class 3 residential part of a health-care building which accommodates members of staff; or
      3. Class 3 residential part of a detention centre; or
      4. building that operates in the event of a bushfire emergency, such as a public bushfire shelter or a bushfire emergency control centre.

(4) The ignition probability for a building must be assessed by application of the following:

1. An event tree analysis of relevant bushfire scenarios.
2. Design bushfire conditions that include combinations of the following actions appropriate to the distance between the building and the bushfire hazard:
   1. Direct attack from airborne burning embers.
   2. Burning debris and accumulated embers adjacent to a building element.
   3. Radiant heat from a bushfire front.
   4. Direct flame attack from a bushfire front.

(5) Applied fire actions must allow for reasonable variations in—

1. fire weather; and
2. vegetation, including fuel load, burning behaviour of vegetation (including the potential for crown fires); and
3. the distance of the building from vegetation; and
4. topography, including slopes and features that may shield; and
5. ignition of adjacent buildings, building elements, plants, mulch and other materials; and
6. effective size of fire front; and
7. duration of exposure; and
8. flame height; and
9. flame tilt; and
10. flame adhesion to sloping land; and
11. the height of the building and its elements.

(6) The assessment process must include consideration of—

1. the probability of non-complying construction of critical aspects of an approved design; and
2. the probability of critical aspects of an approved design being fully functional during the life of the building; and
3. inclusion of safety factors; and
4. sensitivity analysis of critical aspects of a proposed design.

(2) Where a Performance Solution is proposed, the relevant Performance Requirements must be determined in accordance with A2G2(3) and A2G4(3) as applicable.

The Deemed-to-Satisfy Provisions of this Part apply in a designated bushfire prone area to—

1. a Class 2 or 3 building; or
2. a building located in an area subject to a Bushfire Attack Level (BAL) not exceeding BAL—12.5, determined in accordance with AS 3959 that is—
   1. a Class 9a health-care building; or
   2. a Class 9b—
      1. early childhood centre; or
      2. primary or secondary school; or
   3. a Class 9c residential care building; or
3. a Class 10a building or deck immediately adjacent or connected to a—
   1. Class 2 or 3 building; or
   2. a building of a type listed in (b).

In a designated bushfire prone area the following must comply with AS 3959:

1. A Class 2 or 3 building.
2. A Class 10a building or deck immediately adjacent or connected to a Class 2 or 3 building.

(1) In a designated bushfire prone area the following must comply with Specification 43:

1. A Class 9a health-care building.
2. A Class 9b—
   1. early childhood centre; or
   2. primary or secondary school.
3. A Class 9c residential care building.

(2) In a designated bushfire prone area, a Class 10a building or deck immediately adjacent or connected to a building of a type listed in (1) must comply with S43C2 and S43C13.