Noise Insulation Properties
Independent laboratory tests on OZ Roll® AR 400 domestic roller shutters have demonstrated that this product can reduce noise transmission through a window opening. The noise reduction benefits obtained in university tests varied significantly depending on the frequency of the noise source. For low frequencies between 100 Hz and 300 Hz this did not provide any benefits. However, for higher frequencies between 300Hz and 1250Hz the sound transmission loss was improved by 3-10 decibels. At higher frequencies (>1250Hz) the improvement in sound transmission loss with the roller shutter curtain down was typically greater than 10 decibels.
To understand how the change in sound levels (decibels) is perceived, the apparent change in loudness is shown in table 1
Table 1
Change in Sound level | Change in apparent loudness |
3 decibels | just perceptible |
5 decibels | clearly noticeable |
10 decibels | half as loud |
20 decibels | much quieter |
To understand how some common noises compare with changes in sound levels (decibels) and the predicted apparent change in loudness refer to table
Table 2
| Noise | Reduction in Decibels | Predicted subjective response |
| City traffic (10m from kerb) | 4 decibels | just perceptible – clearly noticeable |
| Urban motorway (40m from edge) | 3 decibels | just perceptible |
Jet airliner flying at 300m | 6 decibels | clearly noticeable |
| Dishes being washed (kitchen) | 10 decibels | perceived as half as loud |
| 2 stroke whipper snipper at 7m | 7 decibels | clearly noticeable |
| 2 stroke lawn mower at 7m | 4 decibels | just perceptible – clearly noticeable |
| Small dog barking at 5m | 9 decibels | clearly noticeable – perceived half as loud |
Optimum noise reduction is achieved using an installation with silicone sealant applied between the head box and guides and the wall. To be effective the rest of the home must be sealed properly to ensure there are no air gaps which will allow sound to pass. These air gaps will significantly reduce the effectiveness of the roller shutter and noise reduction benefits will not be apparent
Notes: Noise reduction tests refer to noise reductions achieved in university tests through a closed sliding aluminium framed window with dimensions 1320*820mm. Fitted with a roller shutter (AR400 curtain) mounted ON WALL with silicone sealant applied under the head box and guides for optimum sealing to the wall. The tests only show noise reduction through the roller shutter and no allowance is made for other noise transmission paths such as gaps around doors, ventilation and air conditioning holes in ceilings etc.
