For the sake of time and length, I'll be summarising the following points. However, I go into more detail in my full article which you can download here.
Curtain Wall Perimeter Fire Stop
It can be a struggle determining how to apply AS1530 Part 4 and conventional FRL's to slab edge or perimeter fire stop materials. Many consultants I speak to point me to NCC Clause C3.16 (see below) for construction joints—and without anywhere else, this is probably a good start.
The problem with this approach is that control joints are tested between two fire rated building materials, and while our slab edge is a fire rated building material, the curtain wall is not fire rated. The Europeans have a dedicated fire test method (EN1364-4) for this application, where the fire rated slab edge meets the non fire rated curtain wall building envelope. However, curtain wall fire stop is covered in NCC Clause C2.6, along with spandrels, and are currently only required in non-sprinkler protected buildings, except for the new fire protective timber construction requirement in C1.13. If it was intended to use C3.16, I guess it would say so in C2.6 and at present it does not.
Watch the successful 3 hour fire test incorporating an Aluminium glazed curtain wall façade/concrete floor slab interface sealed with SIDERISE CW-FS perimeter fire stop system, or download the full article to see the fire test images.
Open State Cavity Barriers for Cladding
We are all aware of the cladding pandemic we find ourselves in, and it's sad that the NCC requirements are still ambiguous and not in line with international best practice. Cavity barriers are a proven and cost effective means of stopping fire spread behind the cavities when we clad a building envelope.
Let’s hope logic prevails in terms of cavity systems and we see some more definite technical guidance including fire and requisite movement criteria incorporated into NCC and associated Australian Standards or industry guides sooner rather than later. I would hope our insurance industry reads this and puts out some guidance to minimise damage to building façade fires by way of cavity passive fire protection or cavity fire stopping measures.
Our NCC provide no provisions for so called open state cavity barriers (which you will remember are those that allow ventilation through the cavity barrier in the cold state, and close up using high performance intumescent materials in the hot or fire state). The open state cavity is typically only 25mm or 50mm, which allows the high performance intumescent materials to close off very quickly as proven by fire testing.
Just so you are not confused, a rainscreen cladding system requires provisions for drainage and ventilation, hence why a small section of the cavity needs to be open; the so called open state. Of course in fire it changes by way of the intumescent material expanding and closing the gap changes state to one of closed, stopping fire spread and excessive smoke spread.