Advanced Structural
Designs ACN 097 789 87 92 Vasey Cres Telephone
61612171
Facsimile 61612170 Email mal@structuraldesigns.com.au
Is there
an argument for exceeding current BCA Sound Insulation Requirements?
From a
developers perspective this will depend on whether you intend to sell all of
the units immediately or hold a number as investment units to be sold on at a
later date but in any case there are changes ahead in the industry that you
should be abreast of.
You may be aware
that the current BCA requirements are among the least stringent in the world
and are considered by members of the Australian Association of Acoustic Consultants
to be both inadequate and poorly policed.
Part of the problem has come about because many designers interpret the
STC requirements as applying to laboratory results rather than site measured
situations. This situation has opened up
a Pandora’s box of lawsuits as people opt for the urban alternative. The complaints by occupants have become such
a problem that the Sydney City Council has increased requirements well beyond
the BCA’s current or proposed levels in order to protect itself from future litigation.
In response to
this situation a “regulation document” was release by the Australian Building
Codes Board for comment in January 2001 recommending changes to the BCA, which
will effectively lift the requirements of all future developments.
It may be a
useful sales tool in the future to be able to advertise units as compliant with
the new BCA requirements for sound insulation.
Such compliance would add between 1 and 2 percent to the cost of each
unit if designed in from the outset but would be almost impossible to achieve
once building materials have been selected.
We could
effectively be looking at an underclass of unit construction that the market
marks down if the new noise insulation ratings are not achieved.
In summary the
new recommendations are for an across the board :
Airborne Sound
Laboratory test
performance Rw 55
Site Performance DnT,w 50
Wall Impact
Sound WIC 50
Floor Impact
Sound IIC 50 generally, or 45 where a room is above
another of similar usage and the lower is not bedroom.
For structural
or other engineering advice in the ACT to Mal Wilson or download the RD from
the BCA’s website. The RD covers a large
number of deemed to comply options and makes interesting reading.