A Quieter Life First published in Building Products News, April 2004, ©Reed Business Information Australia 2004

©Reed Business Information Australia

Acoustics consultants are behind a ratings scheme that will raise the level of acoustic performance for domestic dwellings, writes Katrina Fox

Principal of PKA Acoustic Consulting Peter Knowland has witnessed grown people burst into tears when told that, even though they have been driven to distraction by the constant noise coming through their walls from their next door neighbour, the level of sound insulation in their building does in fact comply to Building Code of Australia standards. It was a desire to raise the quality of building standards from minimal requirements to best practice in terms of sound insulation that led the Association of Australian Acoustical Consultants, of which PKA is a member, to launch a star rating system measuring acoustical performance for residential homes.

The system deals with major issues, including the intrusion of external noise, noise generated by building services and appliances and noise transfer between apartments. Each room in an apartment or townhouse is rated individually, then an AAAC Rating Certificate is awarded to the residence as a whole. Ratings range from 2 star to 6 star.
The star rating system measures the actual installed performance of the wall or floor system in a building. "It actually measures what is there and that's a key issue," Knowland says. "There has been a system of measuring the performance of wall systems where academics want it all related to what it would be if it was tested in a laboratory but that's all nonsense - people don't live in laboratories, they live in their own apartments."
A 5 star rating is likely to be the most that can be achieved through what Knowland calls normal building construction. "Once you get up to 6 star and beyond, these type of buildings are going to be pretty rare and they will be beyond in most cases what you can get from normal construction - in other words, you're going to have to think differently to get those performances. When you build a normal building, there's a point you get to where you really can't get any more sound insulation because the sound is travelling in the floor of your room and comes out the floor of a neighbour's room, then into the side walls of your room and out the side walls of the neighbour. For a 6 star rating, a building would need to utilise very innovative technology and I'll probably do four or five of those in my life if I'm lucky."
One of the areas that is most challenging in terms of sound insulation is DVD surround sound systems and home theatres. In the AAAC rating scheme, even with a 5 or 6 star rating, the sound from this type of equipment will be audible. "If you take adjacent cinemas the walls that divide the two from each other are typically 500mm thick and they are providing insulation between one cinema where it may be very loud and another where it may be quiet," Knowland explains. "But even in the quiet one, on average it's still noisier than what it can be in a very quiet home. There are people, and I'm one of them, who run their surround sound system at the same level as the motion picture. If you go into a 5 star rating, you want to run things at a level you feel comfortable with without someone knocking on the wall to tell you to quieten it down.
"So to some degree what we're offering is allowing people to increase the volume so they're enjoying the benefit of their lifestyle but we're also issuing a warning saying that with a DVD with a surround system and particularly sub woofers, the energy that's coming from that is a lot to hold back. Yes it can be done, but we'd end up with unbelievably expensive buildings. We have a client at the moment who wants that and we're giving it to them but it will probably be another two or three years before we get another apartment like it."
It is not only the type of insulation products that are necessary to achieve complete sound insulation in these instances, it is the technology, Knowland points out. "With the current client, their cinema is part of the house so the whole cinema is in a separate room which is all on big rubber pads so it's not touching the rest of the building." But he stresses that with the higher the rating the less audible the sounds from DVD surround systems become. "In 2 star you may as well be there, whereas with 6 star you can hear it, but it's not blaring out."
As far as costs for a rating certificate go, Knowland says the AAAC is going through a process of how to cut both time and costs down in the testing process. "We have made significant inroads on that. For example, the technology for testing the performance of walls, if that was done to be exactly as the acoustic standards set, it's very expensive but we've looked at it and come up with a technology that provides the answer but speeds up whole process. Although it depends on the size of the project, you can pretty well rate an apartment for probably somewhere in the order of $3000. When you're looking at an apartment that is probably $600,000 that's a very small percentage and it increases the quality."
The response from developers has been positive, according to Knowland. "We are currently involved in about eight or nine star rated developments, quite a few at 5 star. We've also heard that other consulting practices have quite a few 4 and 5 star project commissions at the moment. Developers are more than interested. One we spoke to for a very large project in CBD area of Sydney said to me that all buildings will be built to the star rating system within a couple of years. In other words, the public will demand it - once they know they can get this, that's what they will want." Hopefully this will mean that Knowland will no longer need to bring out the hankies.

Building Products News magazine goes out to architects and building designers in Australia. This article is the copyright of the publisher, Reed Business Information and appears here with their permission. For more information on the magazine, visit Reed's website at http://www.reedbusiness.com.au