Specification 43 Bushfire protection for certain Class 9 buildings

(1) This Specification sets out bushfire protection measures for buildings described in G5D4.

(2) Compliance with this Specification does not guarantee the safety of building occupants or the maintenance of tenable conditions within a building during a bushfire event.

(1) The building must be separated from classified vegetation—

1. by not less than the minimum distances specified in Table S43C2; or
2. such that radiant heat flux on exposed building elements will not exceed 10kW/m².

(2) For the purposes of (1), the term ‘classified vegetation’ has the meaning that it has in AS 3959.

(1) The building must be located not less than 12 m from any other building.

(2) The separation distance required by (1) need not be complied with if the building is constructed—

1. with external walls that have an FRL of not less than 60/60/60 when tested from the outside, including any openings protected in accordance with AS 3959 for BAL—19 or greater; or
2. for external walls and roof, using a material or system that satisfies the test criteria of AS 1530.8.1 for a radiant heat flux of 10 kW/m² or greater.

(1) The building must be located not less than 10 m from any allotment boundary or open carparking area/spots.

(2) The separation distance required by (1) need not be complied with if the building is constructed—

1. with external walls that have an FRL of not less than 60/60/60 when tested from the outside, including any openings protected in accordance with AS 3959 for BAL—19 or greater; or
2. for external walls and roof, using a material or system that satisfies the test criteria of AS 1530.8.1 for a radiant heat flux of 10 kW/m² or greater.

The external walls and roof of the building must be protected from potential hazards on the site such as liquefied petroleum gas bottles, fuel storage, storage of combustible materials, waste bins, vehicles, machinery, and the like, by—

1. a separation distance of not less than 10 m; or
2. where within the 10 m separation distance described in (a), constructed with external walls that have an FRL of not less than 60/60/60 when tested from the outside, including any openings protected in accordance with AS 3959 for BAL—19 or greater; or
3. for external walls and roof, using a material or system that satisfies the test criteria of AS 1530.8.1 for a radiant heat flux of 10 kW/m² or greater.

A non-combustible pathway directly adjacent to the building and not less than 1.5 m wide must be provided around the perimeter of the building.

(1) Access pathways that lead to a road or open space must—

1. be readily identifiable; and
2. have an even surface; and
3. have a minimum clear width of not less than 1 m.

(2) If the access pathway is an accessway that is required to comply with Part D4, the requirements of Part D4 override (1) to the extent of any inconsistency.

An external area designed to hold people unable to be safely accommodated within the building, that may be exposed to radiant heat flux from a fire front during a bushfire event, must not be exposed to an incident radiant heat flux from the fire front exceeding 1 kW/m² above background solar radiant heat flux.

To maintain internal tenability throughout the duration of occupancy during a bushfire event, the building must comply with the following:

1. An air handling system must be provided that is capable of—
   1. being adjusted for full recycling of internal air for a period of not less than 4 hours to avoid the introduction of smoke into the building; and
   2. maintaining an internal air temperature of not more than 25°C.
2. The building envelope must be designed such that if an air handling system required by (a) fails, then—
   1. internal air temperatures can be maintained below 39°C; and
   2. internal surface temperatures can be maintained below 60°C.
3. If the building is divided into separate compartments then, for the purposes of (a), each compartment must have a separate air handling system.
4. Each air handling system required by (a) must be designed to account for the activation of smoke detectors from low concentrations of smoke from external sources, so as to ensure that air-conditioning and other essential systems remain operational.

The building envelope must be constructed in accordance with AS 3959 – BAL 19 or greater, except that where the use of combustible materials is permitted by AS 3959, they are not to be used unless permitted by C2D10(4), (5) or (6).

Water for fire-fighting purposes must be available and consist of—

1. a fire hydrant system complying with E1D2, or
2. a static water supply consisting of tanks, swimming pools, dams or the like, or a combination of these, together with suitable pumps, hoses and fittings, capable of providing the required flow rate for a period of not less than 4 hours, determined in consultation with the relevant fire brigade.

(1) Emergency power must be provided to support, for not less than 4 hours before and 2 hours after the passing of the fire front during a bushfire event, the ongoing operation of—

1. air handling systems to maintain internal tenability; and
2. any pumps for fire-fighting; and
3. any emergency lighting and exit signs; and
4. any other emergency equipment listed in C3D14(6) and required to be provided.

(2) Manual control for emergency back-up power supply must be provided to facilitate manual intervention where the power supply fails or runs out.

Signage must be provided to warn building occupants against storing combustible materials under or adjacent to the building.

Vehicular access to the building must be provided in accordance C3D5(2), as if the building were a large isolated building for the purposes of C3D4.