2017 NCC Seminars: Performance Solution - FV1 Weatherproofing

Thank you. Good afternoon all.

Thanks for the opportunity to talk to everyone here. I'm sure most of us here, one way or another, understand the impact of non-performing building materials & systems. I'm talking today from the weatherproofing point of view. Just to give you an idea how important the weatherproofing issue is.

Recently, one of the Australian buildings, less than 10-year-old, had a weather impact issues at a cost of litigation of 50 million dollars. In the US, in the early 70s, about 15 to 20 percent of the litigation against the building personnel, architects, certifiers, builders, product manufacturers and so on, was about 20 percent and it's been gradually increasing. And in the early 2000s, the number has hit every one in two people. Every one in two litigation is related to weatherproofing so it is an important aspect. I'm talking today about the weatherproofing through roofing and cladding.

So the requirement is basically the buildings to resist the moisture penetration. So one in a 20 year storm, any water that comes in has to be disposed and managed so it shouldn't affect the building and any surrounding buildings as well. So the water shouldn't come through openings such as roof, the walls' cladding systems and anything else in the building. So the requirements are ....

before that I might just show you that there is a leaflet in your seat and this tells you the procedure, what needs to be done and what sequence that needs to be  followed. So basically, I will be describing what we have got to go through those processes. So essentially FV1 is the weatherproofing cloth and that directly addresses FV1.4

It's not mandatory but it's one of the alternative solutions. You go through the list in the NCC, look at what is the limitations and what is the score risks factor, and then you choose the test specimen which will comply, and it'll have all the details. For example, the parapet walls, the electrical junctions, the cornice, the terminating vertical as well as horizontal details, and other details.

Complete details of what the realistic system is. And then they choose that as a test specimen and then evaluate whether the system is a direct fixed wall or cavity wall or a unique wall and then go into testing. So, an example of the test specimen is just shown here so that kind of gives you an idea of what I just described. So at the CSIRO, we have got a facility so you can see that there is a double storey height, the chamber in which you can set up the test specimen representing all the details.

And so this particular slide shows you a cavity wall system. Also, the internal view and the external view of a direct fixed wall cladding system are shown in this slide. So they've got pressure equipment to apply the building wind pressures and we have got various data takers and instrumentation to take the required readings.

So essentially for a cavity wall, you set the cavity wall up and drill a 15-millimetre hole in the wall lining to take into account what the air penetration through, air  nfiltration through, and then you must apply 100 percent of the serviceability design loads, both positive and negative, for a minute each, and find out what the  readings would be and what the effect of the wind pressures onto the building specimen.

Following that, you apply a static version water penetration. It is specified at 300 Pascal if the weather pressure is 1000 Pascal or less, and if it is more than 1000 Pascal, it is 30 percent of the design load. Following that, you subject the wall specimen into the third stage of the water penetration specified in the 4284 building code. 4284 which is 30 to 60 percent of the pressure with three litres per minute per square meter area of the test specimen. So after these two tests are over, then you allow the building specimen... subject the building specimen for six millimetre holes at several areas and then you repeat the static and the cyclic water penetration test.

Check if any of the water has reached the interior portion, particularly the studs and the lining of the wall. And if not, then remove the internal lining and then subject the test specimen for 50 Pascal static water penetration. So this particular sequence applies for the cavity wall. And for the direct fixed wall or a unique wall, the first two steps are essentially the same, but then the static pressure and then the full sequence of the three cycles of the cyclic water penetration - 15 to 30 percent, 20 to 40 percent, and 30 to 50 percent of the design load and check through whether there is any particular water penetration.

So that kind of sequence, we are authorised to do these tests in our lab at CSIRO. So once the building specimen is subjected through this sequence, it will prove that you're compliant with the NCC requirements.

Thank you.