To meet the increasing demand for noise reduction in factories and public buildings, the 32/1000LS and 32/1000LN Sheets can be supplied for specialised acoustic applications with perforations in the large pan only or fully perforated across the full cover width. Perforated lining panels achieve a high degree of acoustic absorbency in comparison with the reflective surface of the unperforated sheeting. However, the performance of our cladding systems in relation to sound, or noise, may be considered in respect of three distinct requirements:
– to provide sound insulation (i.e. reduce the level of noise entering or escaping from a building).
– to absorb sound so as to reduce resonance or reverberation.
– to reduce the noise of impact from hail or rain.
The ability of a cladding system to resist the passage of sound is largely dependent on its mass. However, insulation levels are not constant for all frequencies, low frequency sound being more difficult to exclude than that of high frequency. Sound insulation can also be affected by detail design and site workmanship. Badly fitting flashings can allow transmission of disproportionate volumes of noise. Care must therfore be taken at the design stage if acoustic insulation is of prime importnace.
Whenever resonance or reverberation can be identified as a potential problem an expert assessment should be made at the design stage, as modifying an existing building can be both difficult and expensive. Liner sheets can be supplied with various patterns of perforations. This allows sound to escape and be absorbed in the thermal insulation. As less sound is reflected, the acoustic performance is improved.
The impact of rain, or hail, on a roof will always produce a sound. Noise from this source can never be totally eliminated, but it is well established that any flexible insulation layer, directly below the external skin, will have a muffling effect. Insulated Systems, incorporating sandwich construction, thermal insulation and thermal breaks will help to reduce the effects of rain drumming.
Cladding systems may give good performance in all of the above three areas, but good performance in one respect is no guarantee of good performance in the other two. Acoustics is a highly technical subject and where it is of vital importance, expert advice should be sought.