Unwanted sound is considered noise when it intrudes on our daily lives. In controlling noise, whether it be traffic, aircraft or industry related, all aspects of the house/building need to be evaluated, however here we will only analyse the acoustic qualities of two glass types - laminated and double glazing.

Laminated Glass

The polyvinyl butyral interlayer (ranging in thickness from 0.38mm to 1.52mm) used in the laminating process provides a 'dampening' effect which reduces the transmission of sound through the glass. Laminated glass offers superior sound insulation in the higher frequency range where the noise from sources such as aircraft are a problem. Increasing the interlayer thickness will only have a marginal effect on improving the sound insulation qualities of laminated glass. The use of laminated glass is a cost effective solution to noise reduction when compared with double glazed units (see below).

Double Glazing

With double glazing, and more so double glazed windows, it is important to understand that unlike laminated glass, it is the air gap between the two panes of glass that 'diffuses' the transfer of sound. Put simply, the larger the gap, the more the diffusion, the less the amount of sound that travels through to the inside. It is often argued that to achieve a reasonable level of acoustic benefit from double glazing, an air gap of approx. 100mm is required. A unit of such thickness cannot be accommodated within a standard residential window or door frame and so a move up to commercial framing is necessary. Although double glazed units of around 20mm in thickness are used for noise control in homes, the additional cost of the this framing can be significant. A more cost effective solution is the use of a laminated glass product.

G.James has conducted official acoustic testing on various window and door products glazed and manufactured with different glass and seal types. Your G.James representative will be pleased to discuss the results of these tests upon request.

For further information on Sound Insulation refer to page 23 of the G.James Glass Handbook  4,667Kb.