NCC Version:
NCC 2019 Volume 2
Area of NCC Requirements:
Clause 3.7.3.2 – Fire separation between Class 1a buildings
Performance Requirement P2.3.1
Problem :
The construction between Dwelling 2 and Dwelling 3 includes articulation joints (AJs) that are not fire-separated, which deviates from the NCC Deemed-to-Satisfy (DtS) requirements. These joints, if left unprotected, could allow the passage of fire between dwellings, posing a potential risk to life safety and building integrity.
Solution:
A performance-based fire safety assessment was undertaken using expert judgement. The existing construction incorporates a fire-rated Partiwall system (USG Boral Shaft Liner) that effectively separates the dwellings. Additionally, the external walls include a fibre cement sheet with a rendered finish and brick walling, all reviewed and approved by the Relevant Building Surveyor. Although AJs are not fire-rated, this is acceptable under NCC Clause 3.7.2.4(e), which permits small non-fire-rated openings such as control joints. To further mitigate risk, the use of fire-rated sealant within the articulation joints was recommended.
Finalised Report:
The assessment concluded that the existing construction, including the non-fire-rated articulation joints (with proposed fire-rated sealant), provides an equivalent level of fire protection as required by the NCC. The Performance Solution meets the intent of Performance Requirement P2.3.1 and is considered compliant.