Tania Morgun gives an overview of current compliance documents. Tania is a CPEng Fire Engineer with nearly 30 years’ experience. She is a Chartered Member of Engineering New Zealand and practice area assessor for fire. Tania is a Fire Team Leader, so do not hesitate to contact her if you need assistance on regulatory or building code compliance issues on 021 241 5357 or tania.morgun@edc.co.nz.
How good are our current New Zealand Building Regulations?
New Zealand used to be the world leader in performance-based building regulations when the Building Code was first established in 1992. In 2012 the DBH (Department of Building and Housing – now included in MBIE) changed the Building Code and compliance documents for the protection from fire. Ever since, there has been a lot of discussions about whether the Building Code is currently fit for purpose, especially recently.
In the past few years there was a significant shift in the regulatory sector to provide greater clarity in the compliance documents. The way we build is rapidly changing. There are new technologies, building materials, and construction methods. Just to name a few fire risks: lithium batteries, modular construction, and mass timber. The recent fire events in New Zealand and overseas involving combustible cladding materials changed societal expectations, with property protection being as a desirable objective alongside life safety.
In 2024 the Government committed to improving fire safety in buildings to better protect life and property. In October 2024 MBIE identified several issues related to the effectiveness of the fire safety provisions in the Building Code and presented a discussion document for public consultation. The Building Code and compliance documents reflect societal expectation of the performance, i.e. what people are prepared to accept balanced against how much it will cost. We must wait for the outcome of this consultation. It is beginning of a long road, so watch this space.
How good is our current Acceptable Solution C/AS1 for the protection of sleeping uses?
In response to construction industry requests to recognise changing trends in residential construction, and to enable housing densification, in 2022 MBIE proposed to increase the scope of C/AS1, to deliver cost-effective solutions for low-rise multi-unit dwellings, and to address associated fire risks. It was proposed to improve the general level of life safety and property protection in residential homes. MBIE consulted on increased fire ratings from 30-minutes to 60-minutes, updating fire alarm requirements in compliance with the latest Standards, providing more clarity on fire rating of building elements, decks, overhangs, post-fire stability, requirements for the compliance of escape routes, and aligning requirements for the distance separation from 5m to 1m for all multi-unit dwellings.
Public feedback indicated a general support for the intent to increase the level of fire safety, however submitters opposed the changes where they would increase the cost of new buildings, and the MBIE proposals were not fully adopted. The MBIE withdrawn proposals for Parts 4 and 5. C/AS1 were published in November 2023, but requirements for the control of internal and external fire spread are still open to interpretation and remain area of concern for designers and for Councils.
Here is a good example.
On 27 January 2025 MBIE published a Determination 2025/002: An authority’s proposed refusal to grant a building consent for two multi-unit buildings in relation to the application of C/AS1 Part 5 | Building Performance in relation to the Christchurch City Council refusal to grant a building consent for two multi-unit buildings. This Determination considered the application of Acceptable Solution C/AS1 paragraph 5.1.1 for the compliance of external walls design in relation to the boundary.
The proposed building work was construction of two blocks of multi-unit dwellings with a mixed configuration: two two-storey units were located at each end of the building, and in the middle, there were two single-storey units one above another.
In accordance with the Building Act, each block would be considered a building, and in accordance with NZBC clause A1 the whole building would be classified as multi-unit residential.
Simple so far.
But not when the Acceptable Solution C/AS1 is applied. C/AS1 requires single household units and side-by-side multi-unit dwellings to be distanced from the boundary by 1m, but single-storey units, one-above-another must be distanced at least 5m from the boundary without fire rating of the walls. It is obvious that the fire cell of a two-storey building with the same footprint would have a higher fire load (quantity of combustible material to burn) than a single storey building of the same footprint, and the exposed external wall of a two-storey building would be double that of a single-storey unit. No logic at all.
The outcome of the Determination was that the MBIE concluded that each unit is a building, and they have to be considered separately for the compliance with C/AS1.
What to do when you need a solid advice on the fire compliance?
I recommend the first step is to talk to a Fire Engineer you trust and ask them to provide advice. Here at EDC, we have solid fire engineering team with knowledge of first principals, years of experience with regulations, performance-based and prescriptive-based design. We have specialists in passive fire protection, we have a fire engineer with structural background who can sort your post-fire stability questions and review your detailing. Just contact us if you would like to discuss specifics on your project.
