Since the 2019 NCC/BCA came into effect, a lot of confusion and disinformation remains regarding the fire compliance of interior linings used in commercial buildings, as outlined in C1.10 in Volume 1 of the NCC.
There has also been ambiguity regarding the non-combustibility requirements of external walls for Type A and Type B commercial buildings of two storeys or more, as required by C1.9 in Volume 1 of the BCA.
Non-combustibility of external walls in these buildings is critical, so that in the event of a fire, the failure of these components or elements will not allow, for example, the fire to travel up the external face of a building, as happened in the Grenfell fire disaster and many other recent facade fires including those in Melbourne.
As a result of these fires, some ambiguity in the NCC has been removed, and buildings have been ordered to rectify external cladding that is combustible.
However, with these changes, a new ambiguity has been created in the suitability of combustible linings and fixtures when installed on the inside of a required non-combustible wall.
Supawood’s Fire Assessment for non-combustible walls
Finally, the ambiguity has been cleared up by means of a Fire Assessment that Supawood has procured, which has allowed the use of combustible products on non-combustible walls on several projects so far.
This assessment has been procured based on the ABCB Advisory Note on “Fire performance of external walls and cladding” dated 3/2/2020, page 3 and 4, which states:
“A building element is considered to be part of an external wall if it is integral (i.e., is not ancillary) to the construction of the wall. For example, the following elements are considered to be part of an external wall:”
Thereafter follows a list of items including “Internal lining (e.g. plasterboard) of an external wall”.
Thus, if an external wall has been lined with plasterboard, as shown in the photo below, then timber lining may be fixed over this lining and still be compliant, although it is a combustible product.
Timber linings over non-combustible walls - Concord Oval
The timber lining must, however, still be certified to the Fire Group number (1, 2 or 3 as per AS5637.1) as required for the use of that room. This Supawood is also able to supply.
SUPAWOOD’s service
SUPAWOOD would love to help you with the non-combustibility and Fire Group requirements of the linings on your project.
Please contact us for more advice, or for our External Walls Fire Assessment, which allows for combustible linings over a non-combustible wall.
We will also be offering training on the changes introduced by NCC 2022, which come into effect on 1 May 2023.
