Reducing noise in a project to a level that is acceptable is variable depending on the project and the surrounding amenity, taking into consideration factors like traffic, train or planes etc. However no matter how good the window is at keeping noise out, if it is not installed and sealed properly during construction, noise will still penetrate the home.
Sound Transmission Class (STC) reflects the amount of noise that is reduced when sound passes through the window. If the noise outside is 70dB and inside is 40dB, the window is said to have an STC rating of 30. So the outside noise is reduced inside by 30dB. A 10dB decrease in sound is best described as halving of the sound – e.g. a 40dB noise seems half as loud as a 50dB noise. The average spoken conversation makes a 50dB noise, while common street traffic and neighbourhood sounds make about 70dB noise.
The options to reduce noise through glass are:
Laminated glass – The vinyl interlayer will impact on the sound waves. Laminated glass will perform only slightly better than single glazing of equal thickness.
Thicker glass – The further the sound wave has to travel through the density of the glass. Thicker glass is often the best solution to reduce low frequency sounds like common traffic and neighbourhood noise.
Insulated glass units – The key to achieving significant sound wave disruption in an IGU is to have as large an air gap as possible (less than 12mm air gap will provide an STC no better than thick glass); and to have the two panels of glass vary in thickness by at least 50% (so a 10mm panel on one side and a 5mm on the other).
Secondary window – For heavy traffic and aircraft noise a second window with an air space of at least 100mm is the only viable solution to significantly reduce the noise. The use of different thickness glass is recommended, with one of the windows glazed with 10mm glass is ideal.
Acoustic requirements are dependent upon Australian Standards taking into account the building design and the local amenity. Talk to our experienced designers to ensure the right application is made for your project.