A.T.Cowen & Son Ltd

(i)-Sound Control
Introduction

We are all exposed to various types of noise during our daily lives. These noises can be a mixture of traffic, conversation, music, barking dogs and aircrafts etc. Sometimes these noises can become annoying and can often have a serious effect on our health and well being. Excessive noises can cause sleep loss, fatigue, annoyance and stress, heart problems and loss of concentration.

When these noises can't be stopped at source the only remedy is to reduce the level of noise entering the home.
This can be done by using Acoustic Laminated Glass (Sound Control Glass). By using acoustic laminated glass there are also other benefits such as improved safety, security and a reduction in UV light (which can fade furniture and carpets).
Sometimes a homeowner only needs to use acoustic glass on a limited number of windows such as those facing a road, bus stop or playground area.
We stock 3 thicknesses of acoustic laminated glass, 6.8mm, 8.8mm and 10.8mm. When incorporated into a typical Insulated Glass Unit with 4mm glass, the reduction in sound is 37, 39 and 41 dB respectively. This means that the glazing reduces the sound level by those figures compared to 30dB from a standard IGU.

(ii)-Performance
Guidance Notes

According to BS 8233, typical indoor noise levels for a bedroom are 30~35 dB(A) and 30~40 dB (A) for a living room. The table below gives some examples of external traffic noises, target noise levels for bedrooms & living rooms and required window performance.


Figures below show specification for Traffic Noise.
External Traffic Noise	Target indoor noise level in dB (A).	Required Window Performance.
20 meters from a motorway. Average speed of 62mph. Typical noise level = 78 dB (A) Ra tr.	Bedroom 30~35 Living room 30~40	43~48 dB (A) Ra tr 38~48 dB (A) Ra tr
20 meters from a busy main road. Average speed of 31mph. Typical noise level = 68 dB (A) Ra tr.	Bedroom 30~35 Living room 30~40	33~38 dB (A) Ra tr 38~38 dB (A) Ra tr
Residential road (screened by houses) Typical noise level = 58 dB (A) Ra tr.	Bedroom 30~35 Living room 30~40	33~28 dB (A) Ra tr 18~28 dB (A) Ra tr

As you can see from the table above, when your home is close to a residential road the required window performance is met using typical 4-16-4 glazing. Properties close to a busy main road or motorway require up to 38dB / 48dB window performance which is not met by typical glazing and therefore acoustic IGU's would be recommended. Please note that house locations near bus stops and pubs etc would also benefit from acoustic IGU's in a similar way.

(iii)-Questions & Answers

What is "Acoustic Glass"?
- Acoustic glass is a laminated glass that has a PVB interlayer (Polyvinyl Butyral) that reduces the transfer of noise.

Does Acoustic glass eliminate all noise? - No, but the effects of noise will be greatly reduced. Noise is measured in Decibels (dB) and the noise will be reduced by the Db rating of the Glass/IGU. The higher the rating the less noise will pass through the glass.

Does the type of window frame affect the performance of the glass? - Yes, It is the glass and frame that help to reduce the noise. Poor quality frames and badly fitting sashes can still allow sound to penetrate through.

What types of noises will acoustic glass reduce? - Acoustic glass will help to reduce noise levels from all types of sources such as traffic, road works, schools, noisy neighbours, people at bus stops and pubs & nightclubs etc.

Does Acoustic glass offer any other benefits? - Yes, the fact that acoustic glass is a laminated glass also gives the advantage of safety & security to your home. The interlayer also filters 99% of the UV light which can be the cause of faded curtains, carpets and furniture.

How effective is Acoustic glass? - The performance of acoustic glass will vary according to the glass configuration used and the noise source. However, by changing your glazing from typical 4-16-4 to 4-16-6.8. You can reduce the noise by as much as 25%. Further gains can be obtained by incorporating the 8.8mm or 10.8mm versions.

How does Acoustic glass work? - Acoustic glass absorbs and weakens sound, helping to act as a barrier to airborne and impact noise, making your home a quieter place.