2022 NCC Seminars: Volume One - NCC changes

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[Music]

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Hello my name is Graham Moss, I'm the Principal Building  Surveyor for the Australian Building Codes Board.  

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This video is an update on NCC 2022 changes found  in BCA Volume 1. This video is not able to cover  

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all the changes and especially not in detail, this  is why I recommend to you the list of amendments.  

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You'll find the list of amendments in the back  of each edition of the NCC, in the back of each  

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volume, we do this every year we provide a list of  what's changed, so when the publication version of  

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NCC 2022 is released, I do recommend that you have  a look at the list of amendments. NCC 2022 contains  

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a number of changes that have come from the  quantification of performance requirements project  

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for some time now we've been working on this  project which is about quantifying the performance  

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requirements that is taking the subjectivity  out of the points requirements and replacing  

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that subjectivity with numbers quantified targets  so that compliance can clearly be shown and met.

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You may have noticed our public comment  draft that we released for NCC 2022  

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and in that public comment draft we proposed to  change quite a number of performance requirements  

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on account of this particular project. We received  a lot of comment on those those proposals and  

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taking that comment into the consideration the  board chose not to go ahead with these specific  

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performance requirements: the proposed new Part  A8 and also the proposed Junction performance  

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requirement amendments, including that to do with  glass at risk of human impact however these other  

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performance requirements are in 2022 quantified  performance requirements are in BCA 2022 I'll show  

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you those in a moment. But first Part A8, you may  recall this as a new part that was to quantify all  

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the five related performance requirements into one  part found in the new governing requirements, it  

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included tables of acceptable risk for fire spread  and exposing occupants to untenable conditions.

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Of course so that probabilistic risk analysis  could be shown that compliance with all those  

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performance requirements was met. That part did  not go ahead for NCC 2022 however the board of the  

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ABCB is committed to quantification and therefore  please watch this space for future editions of the code.

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Structural quantification also didn't  go ahead this was proposed to have some  

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probabilistic risk analysis applied to structural  performance solutions quite similar to Part A8.

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It didn't go ahead but something similar might be  investigated for NCC 2025, so do watch this space.

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The proposed glazing performance requirements for  glass installations at risk of human impact both  

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Volumes One and Two also did not go ahead for  NCC 2022. Now these are what did not go ahead for  

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NCC 2022 but let me show you what did make it in  for 2022. First is sound insulation quantification  

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this is what FP5.2 looks like today in Volume  One and Volume Two has a similar performance  

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requirement also for attached residential  class ones and the level of performance  

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sought currently in NCC 2019 is this, that  which is sufficient to prevent illness or  

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loss of amenity now this is a subjective measure  of performance there's no numbers to say what is  

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sufficient and of course what might be a loss  of amenity for me might be a different for you.

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So the qualification project came along and  taken the subjectivity out and replaced it  

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with a weighted standardized level difference  with a spectrum adaption term if if relevant now  

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you probably recognize that these numbers come  straight from the existing verification method.

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Next the bushfire performance requirements have  also been quantified for NCC 2022 this also is  

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in both Volumes One and Two, I've got Volume Two  displayed here today. Now NCC 2019 simply says  

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that a building must be designed and constructed  to reduce the risk of ignition from a bushfire.

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What sort of bushfire well that's  where we've quantified it for NCC 2022.

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We've specified a design bushfire that's  a new defined term but as you can see from  

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the definition there we're talking about the  characteristics of a bushfire, ember creation, 

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things like that the characteristics of a  bushfire that has an annual probability of  

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exceedance and annual exceedance probability  not more than 1 in 50. Of course, an annual  

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exceedance probability is the likelihood  of any event occurring in any given year.

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So having established a design bushfire  it's possible to specify exactly the  

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characteristics of those bushfire and therefore  the performance requirement has been quantified.

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Now I need to point out something important  with the quantification of bushfire performance  

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requirements and that is that there is a range  of annual exceedance probabilities for different  

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types of buildings, so H7P5 that I showed on the  previous slide showed a 1 in 50 year probability  

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for a Class 1a building and now it's a relatively  low severity bushfire because it's more likely for  

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a 1 in 50 annual exceedance probability bushfire  to occur in any given year. Now it's been the case  

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in Volume One for some time that you have to  protect Class 2 and 3 buildings from bushfire  

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now you can see that in the quantified performance  requirements these buildings Class 2 and 3 have  

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been given a 1 in 100 year design bushfire, now  of course that's more severe than a than a 1 in 50 year

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bushfire because it's less likely  for that event to occur in any given year.

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For NCC 2022 we've introduced  bushfire requirements for  

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certain Class 9 buildings Class 9  buildings with vulnerable occupants.

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Note that the annual exceedance probability  for these special Class 9 buildings is 1 in 200 years,

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so of course that's a very high relative  severity. Note that the Class 10c private bushfire  

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shelter also receives an AEP of 1 in 200. That's  bushfire quantification, this next quantification  

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occurred just in Volume Two and that's spread of  fire, this is then performance requirement in  

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Volume Two that's behind Part 3.7, that's why the  Deemed-to-Satisfy Provisions require that a wall  

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of a house within 900 of a side boundary will  have to be brick or have a 60 minute fire rating.

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On the screen now is the 2019 performance  requirement P2.3.1 and it says the a

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Class 1 building needs to be protected from the  spread of fire, what sort of fire? Well that's  

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now quantified it's a 92.6 kilowatt per square  meter flux fire, applied over one hour when and  

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also applied within 900 of the boundary or 1.8  meters of another building. Now you've probably  

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noticed that these figures come straight from  the verification methods that are in this section  

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note however that also a probability of 0.01 is  included also, so in other words in order to show  

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compliance with this performance requirement  you need to demonstrate a 99.99% chance that  

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your Class 1 will withstand that 92.6 kilowatt  per square meter flux, for a period of one hour

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The last quantified performance requirement  for NCC 2022 for the building code is automatic  

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warning for occupants now this one's only in  Volume Two and it's the performance requirement  

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that means that houses have to have smoke  alarms. This is what it looks like in 2019

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for 2022 we've added a few more details  but you can see that the quantification

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that is added is efficacy and reliability. These are new defined terms I'm not going  

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to put these up but just describe here that  the effect is very similar to that previous  

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performance requirement about spread of fire, that  is that there has to be a very high probability  

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that the system installed for alerting  occupants of a fire is going to do its job.

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