This video from the 2022 NCC Seminars discusses Section D Access and Egress, and Section F Services and Equipment from NCC 2022 Volume One.
Transcript
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[Music]
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Hello my name is Graham, from the Australian Building Codes Board this video is an update on Sections D and E
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access and egress and services and equipment of NCC 2022 Volume One.
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First change to talk about today is in D2D3 number of exits known in 2019 as D1.2, now I've
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got D1.2 on the screen here from 2019 because I want to show you something that we've changed for
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2022. Notice that number of exits required for a Class 2 to 8 building over 25 meters
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effective height that each story would need to have at least two exits and that makes
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sense because tall buildings present evacuation difficulties. Now D1.2b has to be read alongside
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subclause (g) and subclause (g) says that every occupant of a story, including the ground story,
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in that 25 meter building needs to have access to at least two exits if two exits are required.
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Now consider your typical hole in the wall cafe at the ground level of a building,
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like the one pictured here, now if this building exceeded 25 meters effective height
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then the cafe will not comply with D1.2 unless there's two exits, even if all the travel distances
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required by D1.4 and other parts of the NCC are met because D1.2(g) is saying you have to, that
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every occupant of that particular story including those in the cafe need to be able to get to at
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least two exits without passing through another sole-occupancy unit. So for NCC 2022 we've updated
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D2D3 to remove that requirement for the second exit for a part of a building like that cafe
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which would otherwise meet the travel distance requirements of the BCA. Now on the screen we have
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D2D3(2)(b) which applies for Class 2 to 8s there's also a similar exemption for Class 9 buildings in 4B.
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The next change to show you is dimensions of exits and here on the screen we have BCA 2019
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now you're probably aware that exits and paths of travels to exits need to be at least one meter
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wide that's the D1.6(b)(i). Now you're probably also aware that in certain circumstances the BCA
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allows a ladder to access a space so for instance consider a plant room less than 100 square meters
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it's possible to use a ladder that complies with AS 1657 instead of a traditional step and riser
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arrangement in accordance with BCA 2019 D2. Now those ladders are technically a path of travel to
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an exit and ladders are typically less than one meter wide therefore for NCC 2022 we've included
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this exemption in D2D8 which was D1.6 to include ladders. Now note that these ladders, this exemption
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for ladders are only for ladders that are included for the reasons of D2D21, D3D23 and I3D5 that's
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D2D21 for plant rooms the 100 square meter plant room concession I mentioned just now
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D3D23 which is that provision that talks about allowing AS 1657 platforms and ladders for
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service and storage areas and also of course I3D5 is the provision for farm buildings.
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Now the reason we've actually specified that is the ladder must be provided in accordance
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with these provisions or for the purposes of these provisions is that we don't want
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people coming to site and finding that the exit path is less than one meter and think
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okay here's the solution I'll put in a ladder no it doesn't work that way because the ladder must
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be there for the reasons of those provisions not because there's a pinch point on site.
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This next change is something new but at the same time it might look familiar to you
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and that's because for NCC 2022 except for a standalone primary school that's no taller than
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four stories every part of that primary school must be wholly within a story that provides
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direct egress to road or open space this is a new Deemed-to-Satisfy requirement for NCC 2022.
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If you want to do something different to that so for instance a five-story primary school or
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a primary school in a mixed-use building where the primary school does not have direct egress
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then you need to do a performance solution. As pointed out by the explanatory information on
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this slide this is because of the difficulties associated with the evacuation of primary schools.
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Now if this does sound familiar to you that's because you're thinking of D1.18 in NCC 2019, which
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does similar things for early childhood centers. Now basically what we've done with this provision
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is taken early childhood center and replace that with primary school, now we've done this because
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for early childhood centers we've introduced additional Deemed-to-Satisfy provisions which
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I'll show you in a moment,so that it's no longer necessary to do a performance solution for all
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primary for all early childhood centers that exceed the parameters that are found in D1.18.
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So what was the case for early childhood centers is now the case for certain primary schools
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and those are these so consider building a building A is going to be a performance solution
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it's all the same primary school it's a single-use building, however the building
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exceeds four stories and therefore a performance solution is necessary it's not possible to
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use the Deemed-to-Satisfy provisions of the building code as is the case under NCC 2019.
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Now building B is within that four-story limit it's not a mixed use building and it's all the
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same primary school so under D2D23 it's okay to use the existing Deemed-to-Satisfy provisions.
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Consider building C, building C is also under four stories but it's a mixed-use building now
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a mixed-use building does increase complexity for evacuation however the primary school is at the
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ground level and therefore has direct egress, so under D2D23 you can use existing Deemed-to-Satisfy
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provisions as is the case under 2019. But consider building D the primary school is in a
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mixed-use building yet does not contain direct egress there's another use below it therefore
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building D a performance solution would be required under these new provisions in NCC 2022.
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This new provision D2D23 for primary schools
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has some applications to go with it found in the application box
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now this first application box is clarifying that when we're talking about a primary school of
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course we're talking about kindergarten to year six which is what the Department of Education
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calls a primary school but the application box is saying that when we're talking about a primary
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school we're talking about parts of a school where it's reasonably expected to find students.
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So the staff rooms you could find a primary school student in the staff
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room you could find them in the classrooms of course, the offices, the canteen these
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are all parts of a primary school where the vulnerable occupants can be found.
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Now primary schools are very often found on the same campus or even in the same building as a
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high school or an early learning center or other parts of a school which is still the same school
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and that's why we have this second application.
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What we're saying is that we have a primary school and a high school and it's all the same school and
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it's all in the same building then there's no need to treat the building as a multi-use building for
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egress because the whole building has the same occupant the evacuation problems that would be
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found in a traditional mixed-use building aren't present. So the second application box says that
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it's still a Deemed-to-Satisfy solution if you're less than four stories and the primary school is
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part of a bigger school and note also this extends to the offices, it also extends to
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a different classification a Class 7a car park where it's a car park for that particular school.
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Now that's the new primary school provision which is requiring performance solutions for
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large or difficult to egress primary schools. Now I mentioned earlier that what we'd had done is taken
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early childhood centers out of D1.18 and replaced them with primary schools we're now going to cover
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the changes or the additional Deemed-to-Satisfy provisions for early childhood centers. Now these
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are all the provisions that have been amended to accommodate these new provisions. We're not going
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to cover every amendment in detail but I do want to zoom in on this one A6G1, part of the governing
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requirements, now note that this applies to all early childhood centers in mixed-use buildings.
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This is the 10% concession you know the 10 rule where if you have multiple classifications in the
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same story and one classification is less than 10 percent of the total area of the story then
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you can apply the main classification the greater classification to the entire story.
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Now for a long time that concession hasn't applied to laboratories or to
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residential solo units this year as shown on this slide we've added early childhood centers.
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Now the reason we've done this is because otherwise if you had a large building like
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this Class 6 shopping center and the Class 9b early childhood center was this little part here
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then that would be less than 10 percent and become a Class 6 shop instead of a
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class 9b early childhood center and then would miss out on all these additional provisions.
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Now you may be thinking that this hypothetical early childhood center that I've shown here is on
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the ground floor has direct egress and therefore would not require the additional provisions now
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for most of the provisions that is the case they don't apply, however sometimes they do. I'll show
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you as we go through these provisions which ones do and which ones don't apply to early childhood
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centers with direct egress, but first I'll show you how that's achieved and it's achieved by way of
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these limitation boxes. So these limitation boxes are found when something won't apply to an early
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childhood center that has direct egress or to an early childhood center that's a standalone center
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of only two stories or up to two stories. So this is a particular example is found in
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Specification 17 Clause 14, which is a new provision that requires quick response sprinklers for an
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early childhood center that's at height. Now note how the limitation box removes that require for
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quick response sprinklers to the early childhood centers that are low risk that have direct egress
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and only a standalone story standalone center up to two stories rise in stories.
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Note carefully that some of these new provisions do apply to early childhood centers like those
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depicted on this diagram those that have direct egress or are only up to two stories in standalone.
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I will point it out where they do though most of early childhood centers they're
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at height that don't have direct egress, like this one for fire isolation.
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If the early childhood center is in a mixed-use building it needs to be fire isolated from the
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remainder of the building if you don't have direct egress as shown on the right the diagram on the
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left the ECC the early childhood center has direct egress and therefore C3D6 does not apply there's
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no necessity to fire isolate the early childhood center from the remainder of the building.
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So next is compartmentation within the story itself so each story the center needs to be
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separated into at least two fire compartments of course this applies only when we're at EEC's
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that are at height, this won't apply to the single story direct egress or the double
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story direct egress early childhood centers. Exits, so if you have an exit ramp it needs to
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be fire isolated again this only applies to the early childhood centers that are found at height .
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Also in Part D2 is horizontal exits where you have to divide your story into fire compartments each
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compartment has to have at least two horizontal exits and of course those exits need to be at
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least nine meters from one another and also nine meters from any other exit. You also have to be
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able to fit the entire population of the story in either fire compartment you can see that
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these provisions are about creating opportunity for staged evacuation getting the vulnerable
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occupants away from the fire affected compartment which of course buys time for assisted evacuation.
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Next in Part D3 we require appropriate handrails and balustrades you may be aware that in a primary
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school we require additional kid-sized handrails for stairs and ramps to in addition to those that
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are required for adult size, we've got kids size handrails. Well for NCC 2022 we now require toddler
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sized handrails for early childhood centers. Now note carefully that there's no limitation box
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on this new provision this applies across all early childhood centers, also I need to point
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out for Part D3 that even though in the example on the screen here we have fire isolated exits
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you'd be aware that fire isolated exits have a concession in the barrier for 300 sized openings
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300 millimeters instead of 125 millimeter size openings well for an early childhood center that
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concession is removed you must bring it down to 125 millimeter opening maximum because of
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course we have little people using these exits and therefore we need to make them suitable.
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Finally sprinkler protection now sprinklers aren't required in that standalone early
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childhood center up to two stories in height or where we have direct egress, but in a mixed-use
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building like the one shown on the right where the early childhood center does not have direct
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egress then the whole building not just the early childhood center but the whole building needs
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sprinkler protection and as I showed earlier the early childhood center needs quick response heads.
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I just want to point one thing out about those quick response heads and I'll do that using the
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examples shown on this slide. On the left here we have an early childhood center in a building that
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exceeds 25 meters effective height so of course on account of exceeding 25 meters effective height
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the building on the left requires sprinkler protection. Now the early childhood center
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is receiving sprinklers in that building on the left not because it's an early childhood center
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because as you can see the early childhood center has direct egress these additional requirements
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don't apply. No, that early childhood center is receiving sprinklers because it's in a building
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that exceeds 25 meters effective height, in that case standard heads are fine they're satisfactory.
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Now consider the building on the right that building needs to be sprinkler protected
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because it exceeds 25 meters effective height that's true but note the early childhood center
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is found at height there is no direct egress and therefore that provision I showed
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earlier applies and the early childhood center must have quick response heads.
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Finally smoke detection now note that this one applies to all early childhood centers that is
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for NCC 2022 smoke detection and alarm systems are required now in every building that contains an
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early childhood center. Including those that enjoy direct egress, no limitation box found on this one.
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so those are the changes for early childhood centers.
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This next change is D3D16 currently known in NCC 2019 as D2.15, now for 2022 we've added the words
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in resident use areas for Class 9c residential care buildings that's there in subclause (b).
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I've shown you this definition on this screen we're talking about the residential areas of a building.
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Now you'll notice that this matches subclause (a), which describes hospitals and how the patient care
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areas for a Class 9a healthcare buildings are the only parts caught by subclause (a).
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Now this is fixing a small problem that's currently in the code because currently you
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can't have a step anywhere near the threshold of any doorway in the whole Class 9c building,
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even the back door used only by staff where a step is going to be useful to stop the rain coming in.
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Now in the current code subclause (b) overrides (d) which is the concession that allows that back
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door to have a step. Now i'm told this is a common performance solution for
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really what is an unintended oversight in the code so that's now fixed for NCC 2022.
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This next change is to do with balustrade specifically face mounted balustrades and note
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this changes found in Volumes One and Two. When I talk about a face mounted balustrade that might be
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achieved by a spigot mount or it might be achieved like a bracket mount like in this photograph.
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This is any configuration that's creating a gap between the edge of the traffickable surface
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that's been protected and the balustrade, now some might say that under the current code that this
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is this face mounted balustrate is okay so long as that gap doesn't allow a 125 millimeter sphere to
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pass through, however a 125 millimeter gap is a big gap in that location and also I want to suggest to
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you that if your barrier is set away from the side especially 125 millimeters away then it's
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hard to say that your barrier is provided along the side of the traffickable surface which is
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the current requirement shown here for BCA 2019 Volume Two, similar wording is found in Volume One.
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However we do note that this is a popular balustrade design and therefore we've included
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for both Volume One and Two this edition that is we're allowing face mounted barriers so
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long as the gap measured horizontally doesn't exceed 40 millimeters. Now please do note that
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this 40 millimeter allowance doesn't somehow stack with 125 millimeter provision that
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exists today so you can't get a larger gap from that 125 it's still the case that the
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125 sphere can't pass through any part of the barrier it's simply that we're permitting the
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barrier to be located away from the edge so long as that awayness doesn't exceed 40 millimeters.