C/AS changes - external cladding HRR

In case anyone wasn’t aware, the Acceptable Solutions had a revision on the 4th of January. Most of the changes were fairly minor, but one to be aware of is clause 5.8.3 has been deleted. This allowed combustible cladding on buildings over 7m to 25m if it was sprinkled. This allowance has been removed, mainly as a result of the Docklands fire and the other impressive ones in Dubai around the same time, where there was significant fire spread up the building, despite sprinklers in the building. The Melbourne Fire Brigade report into the Docklands Lacrosse fire is an interesting read, especially against some of the assumptions we have on occupancy and evacuation times. Like in NZ, the decks weren’t sprinklered as they were small enough not to need it and there was supposed to be no storage on the deck, and none of the reports have any comment of what would have happened if they had been sprinklered. It may have been controlled or limited, although this wouldn’t help with e.g. a rubbish skip close to the building (which should not be there as it is contrary to clause 206 of NZS4541…)
If you have a project with timber weatherboards or plastic cored ACP panel and a max height >7m being lodged after May 30, then this will affect you.
If it is 2 stories, it may still be affected, as the old Nelson blocks used in schools in the 1960s are 8m high.

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thanks for the post Geoff. I note that there are some other untested/non based changes such as the extension to the travel distance in AS for houses. Apparently if you put a domestic hard wired in the travel distance magically increases to 35m. It appear this was based on some 1997(!) data and a report from BRANZ in 2000. I can only guess that a cost benefit has not been taken. I do understand that the BRANZ report says “a case MAY be made” not "we should fit these. I also note that the CBA for the domestic type 1 (as we have now) almost failed, so the CBA for this system would make interesting reading…

C/AS6 still allows combustible cladding up to 25m. This is possibly an oversight because 5.8.3 was deleted but because sprinklers are mandatory 5.8.1b was not amended.

C/AS1 allows combustible cladding up to 10m

I suspect that is an oversight on C/AS6. If these are single storey industrial buildings, is it actually an issue?
Any connections between houses (C/AS1) and any fire engineering design are coincidental - societal accepted risk, backed up by the fact that fire spread between houses is much rarer than theory suggests.

One for the peanut gallery for discussion is industrial buildings and I don’t know the answer offhand . What about structural insulated panel (polypanel) buildings, such as coolstores, or food processing plants. I imagine most of the skins are steel, not aluminum, so can be tested with the skin on, hence the “cladding” is non combustible.
What about if an ali skinned panel is used as this would need to be tested without the skin, exposing the foam core. PIR (kingspan or Polyphen) may pass (although I haven’t looked for any tests)c but EPS won’t .
Does anyone know if aluminum cladding over the foam core is used on any SP systems or as facade elements? Is this actually an issue?

Typically most insulated panel systems - coolstore & cleanroom construction these days are colorsteel (metal) clad and the cores are PIR, mineral fibre or blended with a phenolic resin to achieve fire retardancy.
I would suggest approaching representatives of Kingspan / Metalcraft / Bondor and Insulated Panel Council Australasia for further comment and maybe statistics on what products percentage is in the market place.