Determining the "effective height" of a building for the purposes of the Building Code of Australia

In brief - Required fire controls and safety features vary according to "effective height"

In The Owners - Strata Plan No. 69312 v Rockdale City Council & Anor; Owners of SP 69312 v Allianz Aust Insurance [2012] NSWSC 1244, the Supreme Court has interpreted the definition of "effective height" in the Building Code of Australia (BCA). This is important because particular buildings have different requirements for fire controls and safety features and systems, depending upon the effective height of a building, as defined in the BCA.

Definition of the effective height of a building

It was agreed by the parties that under the BCA, a proposed building with an effective height over 25 metres had more onerous fire safety regulatory requirements. Between January-October 2001 (when the consent and construction certificate had been issued for the proposed building), the definition of effective height in the BCA was "the height of the floor of the topmost storey... from the floor of the lowest storey providing direct egress to a road or open space."

Was the lowest story the lower ground level or the upper ground level?

The court looked at whether "the floor of the lowest storey providing direct egress to a road or open space" of the proposed building was, on the facts:

• the upper ground level, which was the pedestrian entrance to, and exit from, the proposed building (contended by the defendants), giving the proposed building an effective height of 25 metres; or

• the lower ground level, which was the vehicular entrance to, and exit from, the proposed building (contended by the plaintiff), giving the proposed building an effective height of 26 metres.

The court found that the internal configuration of the proposed building did not determine "effective height", and that the distance between the topmost storey of the building and the points of egress (exit) applied to the definition.

"Egress" defined as point of exit, rather than escape route

The word "egress" implied:

• at least one, and possibly more than one, point at which occupants of the proposed building could exit to a road or open space; and

• the existence within the proposed building of a pathway reasonably accessible from the point of egress to the whole of the building or, at least, a substantial part of it.

As a result, the court found that the word "egress" was a point of exit, rather than an escape route.

Lower ground level the lowest storey providing direct egress

Based on the facts, the lower ground level of the proposed building was the "lowest storey providing direct egress to a road or open space", because of the definition of "storey" in the BCA. It provided space for parking in excess of three vehicles and it had direct egress to the street.

The upper ground level was not the preferred storey for various reasons, including the fact that the pedestrian entrance to the level was via doors that divided a foyer area from a covered verandah and was several steps up from the footpath on the street. A person was required to pass through the verandah area and down steps before reaching the footpath.

Notwithstanding the above, the court still found that the upper ground level could reasonably have been characterised as "a storey providing direct egress to a road or open space" within the definition of "effective height" within the BCA. The BCA definition of "effective height" was not inconsistent with a building having points of egress at more than one level.

BCA Guide definition not relevant

The court held that the BCA Guide was not relevant to the proper determination of the definitions in the BCA, as the text of the BCA itself is clear and capable of ready, reasonable application.

Effective height of the building was 26 metres

On the facts, the lower ground level was "the lowest storey providing direct egress to a road or open space" of the proposed building. Accordingly, the "effective height" of the proposed building was 26 metres.

Implications for owners, builders and developers

The case has significant implications for owners, builders and developers. It provides a further guide as to how the court will interpret "effective height", which may have significant consequences in terms of regulatory compliance with fire controls and safety measures.