Noiseless homes

TO COMBAT noise pollution, United Kingdom's (UK) Building Research Establishment (BRE) recently undertook some innovative research aimed at providing noise-insulated dwellings to people. The project includes persuading architects to design houses with considerable insulation against cacophony and finding out construction material that keeps out the maddening noise (Spectrum, No 246).

The preliminary survey out of a series of surveys conducted in the '90s by the BRE under Colin Grimwood reported that "traffic, ghetto- blasters, barking dogs, banging doors and chatter from neighbours blight the lives of 18 million people in the UK." Even the sound of church bells acted as an irritant to some people. Another BRE survey revealed that more than half the homes in the UK suffer daytime noise levels above the World Health Organization's recommended limits and two-thirds are exposed to noise above the stricter night-time limit.

Out of 2,373 adults interviewed from a randon-Ay selected sample, 30 per cent complained of noise from road traffic, over 22 per cent objected to noise from neighbours, 16 per cent from aircrafts; and 4 per cent from trains. "A similar survey in the '8 os showed that 11 per cent were affected by traffic and 14 per cent by noise from neighbours", says Grimwood. Apparently, this increase in the number of people objecting to noise pollution is attributed to underestimation of the problem in the past.

Though the UK has appropriate construction regulations for ensuring sound insulation between houses, a third BRE survey has reported that in majority of cases the buildings failed to comply with the regulations. Interestingly, the research has indicated that noise enters the buildings through windows that are not properly seated.

'Quiet Homes' is the title of the scheme currently being developed by BRE, in collaboration with builders and material producers for incorporating noise-insulated building techniques and materials to construct environment-friendly buildings. A new software programme has also been designed by BRE that can aid architects to assess the noise insulation measures at the design stage itsed, in association with their computer aided design drawings.

In addition, useful information based on research at BRE's echo-free and reverberant chambers on the ways to control noise pollution is provided by a BRE publication called Sound Controlfor Homes. Households are advised to minimise irritation by external noise by preventing the transmission of sound from one dwelling to another. "Washing machines are a particular problem, especially when used at night", says Grimwood. Mountings made of different materials are also being tested so that the noise is absorbed bythem and not transmitted through the floor.

The organisation is now collaborating with France and Sweden to improve the accuracy and efficiency of testing methods for impact-sound insulation of floors. As Grimwood rightly puts it, "We don't want to turn the dwellings into fortresses, but what we do need is a greater compliance with the building reaqlations."

In the UK, a large conversioii work was@ undertaken to cover the floors with thin finishes. This revealed that 11 ac@ording to the tapping machine they give insular improvement, but with the feet they don't." This is attributed to the measuring machine fitted with 5 ham- mers, that can give misleading results on car'peted or lightweight floors.