This video from the 2022 NCC Seminars discusses changes for NCC 2022 Volume One.
Hello my name is Graham Moss, I'm the Principal Building Surveyor for the Australian Building Codes Board.
This video is an update on NCC 2022 changes found in BCA Volume 1. This video is not able to cover
all the changes and especially not in detail, this is why I recommend to you the list of amendments.
You'll find the list of amendments in the back of each edition of the NCC, in the back of each
volume, we do this every year we provide a list of what's changed, so when the publication version of
NCC 2022 is released, I do recommend that you have a look at the list of amendments. NCC 2022 contains
a number of changes that have come from the quantification of performance requirements project
for some time now we've been working on this project which is about quantifying the performance
requirements that is taking the subjectivity out of the points requirements and replacing
that subjectivity with numbers quantified targets so that compliance can clearly be shown and met.
You may have noticed our public comment draft that we released for NCC 2022
and in that public comment draft we proposed to change quite a number of performance requirements
on account of this particular project. We received a lot of comment on those those proposals and
taking that comment into the consideration the board chose not to go ahead with these specific
performance requirements: the proposed new Part A8 and also the proposed Junction performance
requirement amendments, including that to do with glass at risk of human impact however these other
performance requirements are in 2022 quantified performance requirements are in BCA 2022 I'll show
you those in a moment. But first Part A8, you may recall this as a new part that was to quantify all
the five related performance requirements into one part found in the new governing requirements, it
included tables of acceptable risk for fire spread and exposing occupants to untenable conditions.
Of course so that probabilistic risk analysis could be shown that compliance with all those
performance requirements was met. That part did not go ahead for NCC 2022 however the board of the
ABCB is committed to quantification and therefore please watch this space for future editions of the code.
Structural quantification also didn't go ahead this was proposed to have some
probabilistic risk analysis applied to structural performance solutions quite similar to Part A8.
It didn't go ahead but something similar might be investigated for NCC 2025, so do watch this space.
The proposed glazing performance requirements for glass installations at risk of human impact both
Volumes One and Two also did not go ahead for NCC 2022. Now these are what did not go ahead for
NCC 2022 but let me show you what did make it in for 2022. First is sound insulation quantification
this is what FP5.2 looks like today in Volume One and Volume Two has a similar performance
requirement also for attached residential class ones and the level of performance
sought currently in NCC 2019 is this, that which is sufficient to prevent illness or
loss of amenity now this is a subjective measure of performance there's no numbers to say what is
sufficient and of course what might be a loss of amenity for me might be a different for you.
So the qualification project came along and taken the subjectivity out and replaced it
with a weighted standardized level difference with a spectrum adaption term if if relevant now
you probably recognize that these numbers come straight from the existing verification method.
Next the bushfire performance requirements have also been quantified for NCC 2022 this also is
in both Volumes One and Two, I've got Volume Two displayed here today. Now NCC 2019 simply says
that a building must be designed and constructed to reduce the risk of ignition from a bushfire.
What sort of bushfire well that's where we've quantified it for NCC 2022.
We've specified a design bushfire that's a new defined term but as you can see from
the definition there we're talking about the characteristics of a bushfire, ember creation,
things like that the characteristics of a bushfire that has an annual probability of
exceedance and annual exceedance probability not more than 1 in 50. Of course, an annual
exceedance probability is the likelihood of any event occurring in any given year.
So having established a design bushfire it's possible to specify exactly the
characteristics of those bushfire and therefore the performance requirement has been quantified.
Now I need to point out something important with the quantification of bushfire performance
requirements and that is that there is a range of annual exceedance probabilities for different
types of buildings, so H7P5 that I showed on the previous slide showed a 1 in 50 year probability
for a Class 1a building and now it's a relatively low severity bushfire because it's more likely for
a 1 in 50 annual exceedance probability bushfire to occur in any given year. Now it's been the case
in Volume One for some time that you have to protect Class 2 and 3 buildings from bushfire
now you can see that in the quantified performance requirements these buildings Class 2 and 3 have
been given a 1 in 100 year design bushfire, now of course that's more severe than a than a 1 in 50 year
bushfire because it's less likely for that event to occur in any given year.
For NCC 2022 we've introduced bushfire requirements for
certain Class 9 buildings Class 9 buildings with vulnerable occupants.
Note that the annual exceedance probability for these special Class 9 buildings is 1 in 200 years,
so of course that's a very high relative severity. Note that the Class 10c private bushfire
shelter also receives an AEP of 1 in 200. That's bushfire quantification, this next quantification
occurred just in Volume Two and that's spread of fire, this is then performance requirement in
Volume Two that's behind Part 3.7, that's why the Deemed-to-Satisfy Provisions require that a wall
of a house within 900 of a side boundary will have to be brick or have a 60 minute fire rating.
On the screen now is the 2019 performance requirement P2.3.1 and it says the a
Class 1 building needs to be protected from the spread of fire, what sort of fire? Well that's
now quantified it's a 92.6 kilowatt per square meter flux fire, applied over one hour when and
also applied within 900 of the boundary or 1.8 meters of another building. Now you've probably
noticed that these figures come straight from the verification methods that are in this section
note however that also a probability of 0.01 is included also, so in other words in order to show
compliance with this performance requirement you need to demonstrate a 99.99% chance that
your Class 1 will withstand that 92.6 kilowatt per square meter flux, for a period of one hour
The last quantified performance requirement for NCC 2022 for the building code is automatic
warning for occupants now this one's only in Volume Two and it's the performance requirement
that means that houses have to have smoke alarms. This is what it looks like in 2019
for 2022 we've added a few more details but you can see that the quantification
that is added is efficacy and reliability. These are new defined terms I'm not going
to put these up but just describe here that the effect is very similar to that previous
performance requirement about spread of fire, that is that there has to be a very high probability
that the system installed for alerting occupants of a fire is going to do its job.