You may all have been faced with a canopy/walkway between buildings on a same title/boundary (please find below). Christchurch City Council asked us in some similar projects to conduct a “life safety assessment” of all the blocks on a site as CCC think they should be treated as a single building because they are linked together by an external roofed area (open sided building) for achieving compliance with C1-C6 of the New Zealand Building Code) modified by section 1.3 to align with the requirements of Section 112 of the New Zealand Building Act.
The alternative they specified is if we can demonstrate spread of fire will not occur between blocks then we can treat them as separate buildings.
First of all, I wonder where this argument come from? The only section of Acceptable Solution discuss about “open sided buildings” is in Paragraph 5.6.6 which is for external spread of fire (not between buildings on a same title)
Then, conceptually, if a walkway is an open-sided space, and complies with the requirements of Paragraph 3.11 on C/AS; what risks is still there?!
This looks like any of dozens of schools around the country.
My understanding is that legally it is one building due to the connecting canopies so you have a continuous footprint, although it is playing with legal niceties. If you asked the famous “man on the Claham Omnibus”, I am sure they would say they are individual buildings.
Since it is a S112 alteration with awake people, there are no “other property” issues in the NZBC. You are only looking at fire spread to the adjacent buildings as far as they hinder escape - if they burn down after everyone is out, it doesn’t matter, ignoring any client requirements.
Assuming a reasonable separation (so the buildings are in fact separated) and with an interconnected alarm that sounds in both buildings and awake and mobile occupants, you would be unlikely to get fire spread to the other building before flashover or ventilation limited burning and you can calculate this time and also the radiation from a localised fire and hot layer for completeness if you need to. I expect it will be well after the people in the building on fire are out (since they are dead otherwise) and the people in the other buildings will be out shortly after the people in the fire building have left.
This will lead to another challenge. If all buildings linked by covered canopies are considered as 1 building then it drives the requirement from the MoE to sprinkler protect buildings larger than 1000m2.