Sound Reduction

Sound doesn’t have to be complicated…

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Overhead Aircraft 50 Mtrs

140db - 130db

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Pain Threshold


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Rock Concert

110db - 100db

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Heavy Goods Vehicle


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With a constant value as low as 75dB there is a risk of noise deafness


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Normal Speech

60db - 50db

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Quiet Forest


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Radio Station Studio


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Rustling Leaves

10db - 0db

British Airways Boeing 777 flying over roofs

How does sound travel?
Sound travels through the air like ripples on a pond surface when a stone is dropped into it. The sound radiates outwards in all directions from the source, gradually reducing in intensity or until an object stops its progress.

Sound (dB Decibels)
Sound is described in different ways but primarily in terms of intensity and frequency. The sound intensity is described in dB. A low dB indicates a soft sound, a high dB value indicates a loud sound. Frequency describes how high or low-pitched the sound is (Hz).


Sound Reduction
A sound’s volume set at 60dB decreased by…
-3dB is just perceptible
-5dB clearly noticeable
-10dB Half the original volume

Recommended Indoor Ambient Noise Levels

Bedrooms 30-35dB
Living rooms 30-40dB

Private 35-40dB
Open plan 45-50dB

Typical noise levels
50 metres overhead aircraft 140dB
Car alarm 120dB
Passing train 90dB
20 metres from a busy carriageway 78dB
20 metres from busy main road 68dB

Sound reduction test
A three-panel horizontal sliding secondary glazing unit (1960mm x 1190mm High) was sent to the Building Research Establishment in Watford for testing

How was the test carried out?
A cavity wall was built into the aperture between two rooms of the BRE transmission suite to the following specification
Block thickness 100mm
Block density 1800 kg/m2
Cavity spacing 75 – 80mm
Finished with plasterboard on dabs.

An aperture was left in the wall to house the window. A typical Georgian window from a Builders Merchant with three openers was fitted.

opening window vents

The secondary was installed behind the window on timber liners to provide a minimum pane spacing of 100mm. The condition of the primary window will have an effect on the overall system performance.

sleeping newborn baby

Keeping sound in - 70% of people admit to feeling harassed by noise
Loud music remains the main source of noise complaints in England, Scotland & Wales. Secondary glazing is an excellent solution for Hotels, Pubs & Clubs or factory’s close to housing to keep noise in.

New Glass Technology
Acoustic laminated glass (Silence) is the latest product to come onto the market. Two sheets of glass are bonded together with a 0.76mm thick layer of special acoustic polyvinyl butyral (PVB). Solaglas estimate a 20% improvement over standard glass. Taking this increase into account when installed into our secondary glazing a reduction of 44-45dBs should be easily achievable. Silence Glass is a safety glass so can be used in safety critical areas and meets the requirements of BS6206.

Primary WindowSecondary
RWSound reduction
over test window
in %
14mm GlassNoneStandard pile26
24mm Glass4mm GlassStandard pile3965%
34mm Glass6mm GlassStandard pile3965%
44mm GlassLaminatedStandard pile4070%