NOISE REDUCTION PROPERTIES
Unwanted sound or ‘noise’ is everywhere. Whether it originates from road traffic, aircraft, factories, discos or merely from neighbours, noise is a nuisance which can, in the extreme, cause physical and psychological illness, a fact recognised and campaigned against by the World Health Organisation.
Typical 4mm toughened glass will provide a mean noise reduction of Rm = 27dBA while double glazing with a 12mm hermetically sealed air-filled cavity, again using 4mm toughened glass, gives Rm = 29dBA. This 2dBA difference in sound intensity between single and double glazing would barely noticeable for the average person, thus demonstrating that standard double-glazing is not always a suitable and cost effective solution for noise insulation.
Approximate typical actual noise levels:
- Motorway 80dBA
- City centre 75dBA
- Major road 70dBA
- Minor road/Residential 60dBA
Recommended maximum noise levels
- Bedroom 30-35dBA
- Living room 30-40dBA
- Office (Open plan) 45-50dBA
In a carefully controlled test, Storm Windows, using only a 40mm air cap and 4mm toughened glass reduced noise to 40dBA (please ask for a copy of the independent record). Noise is measured on a logarithmic scale. In real terms the result is a noise reduction of more that twice that of double-glazing, (Fig 1). The larger air space decouples the acoustic vibration usually present with single or standard double-glazing. The additional mass of glass improves the sound absorption of the total assembly. Space allowing, increasing the air cap up to a maximum of 200mm can also provide enhanced sound insulation.
Therefore, even with buildings close to a motorway, Storm Windows will help you to comply with maximum recommended noise levels in most domestic and commercial buildings, depending on the properties of the existing primary window and frame.
The addition of a secondary panel constructed from 4mm toughened glass will result in very little reduction in light transmittance.
Reduced air flow and particulate ingress
Due to the unique ‘thermo-magnetic’ Storm Windows sealing system, very good air tightness is achieved. This is important not only for excluding unwanted draughts, dust and other airbourne contamination, but also for maintaining high levels of sound insulation. Air gaps of only 1% of the total window area can increase the sound transmission by 10dBA. Therefore it is important that secondary windows should be purpose built in order to suit a particular opening.
Mrs March, Derbyshire
"The heating bills are considerably reduced and we noticed how much warmer the house was immediately.”
Mrs March, Old Chapel
“Even the early morning mail plane is barely noticeable and it is so quiet in the evenings you can hear a pin drop. The heating bills are considerably reduced and we noticed how much warmer the house was immediately. Another benefit is that, although we live in a lovely quiet area with little crime, having secondary glazing gives me more confidence that a thief could not just smash through one of our lovely windows and break in as easily.”
Mr Butler, Mere Hall
“These very old leaded lights can get really out of shape without breaking so the secondary glazing unit required to protect this area had to be carefully configured. Storm Windows surveyed the whole area to within 1mm tolerance and produced a unit that would do the job without a heavy timber frame. Now it is fitted it is virtually invisible, in fact, until I got used to the windows I kept hitting my head on them when I went to look out as I forgot that it was there.”