Hello, my name is Simon Bradwell from ABN Pax here in Melbourne and today I'm going to talk to you about centrifugal fans, as we've had quite a lot of questions recently asking us what is a centrifugal fan? I've got a range of centrifugal fans here in front of me and each of these fans turns air through 90 degrees. I've got two forward curve fans, one without housing, this one here, and one with housing, this one here, and I've got a backward curve centrifugal fan, one of our radical fans. To explain the air, the air comes in here and gets thrown at 90 degrees by the backward curve blades. This is also shown in this short illustration here. There are five standard types of centrifugal fan, which are defined by their blade type. First of all there's a backward curve blade, secondly a backward curved inclined blade, thirdly a backward curved inclined airfoil blade, then there's a radial blade and a forward curved blade. Now these perhaps fans are available in both housed and non-housed versions as I explained earlier and there's also a product called a mixed flow, which doesn't quite turn the air through 90 degrees but it turns air through less than 90 degrees and there are definitions within the standard of what actually compromises a mixed flow fan. Now centrifugal fans are typically used for shifting air against a reasonable static pressure and are typically used from maybe 150 passcals up to 1500, 2.5,000 passcals and therefore often used in housing and building type applications where air needs to be moved down a duct or air needs to be moved through a heat exchanger or some kind of static resistance. And here's an example of a plug fan and how it's arranged typically without housing. And here's some images with respect to the use of backward curved plug fans without housing and forward curved fans in an air handling unit and you can see that the layout of the fans are fundamentally different in that the backward curved fan without housing or the plug fan is positively pressurising a planum whereas the forward curved fan is blowing air in a direction of a duct. Also the air intake onto the two fans is completely different. Now I said that the centrifugal fans were defined by that blade type but they're also defined by their efficiency and here in Australia you can go to the Fan Manufacturers website www.fmaanz.com.au and there you'll see a code of practice for minimum efficiency standards and high efficiency standards for a range of different fan types. Now to give you an example the defined minimum efficiency standards for a mixed flow has an an an or a fan minimum efficiency grade of 47. A forward curved has a efficiency grade of 37 whereas a backward curve is much more efficient and has an efficient minimum efficiency grade of 58. Now this is really useful for people who want to specify fans for their application in a hand-bending units for instance and details associated with the Fan Minimum Efficiency Grade can also be found in the Australian standards. So today I've talked about centrifugal fans. Centrifugal fans turn air through 90 degrees, they bring air in the inlet and blow it out at 90 degrees. They're fundamentally five types of centrifugal fan and they're defined by their blade type and the efficiencies of the centrifugal fans vary from 37 for forward curve fans all the way up to minimum efficiency standards of 58 for backward curve fans. I hope that's been useful. There's further information on our website www.ebmpaps.com.au and ebmpaps.co.nz if you need some more information. Thank you very much.