No drainage system can offer the guarantee of total silence and a peaceful night’s sleep

Despite the certifications presented by manufacturers obtained from accredited laboratories, the mechanical and physical properties of even the best performing drainage system cannot meet the requisites for passive noise levels set by DPCM 5/12/1997. This is because the maximum permissible noise level indicated for a drainage system (35 dB) is applicable for the installed system in a finished, habitable building. This means that as well as choosing the materials carefully, the system itself must also be painstakingly designed and installed to the highest possible standards, with a project manager who verifies that the installation is performed correctly according to the plan. 

Choosing the right cladding material: FONOdBAM or FONECOdBAM?

The choice of cladding material must consider the type of drainage system, the type of wall the pipe passes through, and the desired results in the finished installation (acoustic class in accordance with UNI 11367). Only once all these factors are known can the right material be recommended. This may be a single layer elastic material, where a physical isolation function is required to prevent direct contact between structural elements and the drainage system: in this case, the FONOdBAM liner, consisting of 5 mm thick closed cell expanded polyethylene foam. If sound insulating properties are also needed as well as physical isolation, the FONECOdBAM stratified panel should be used. This is a composite material consisting of inner and outer layers of closed cell reticulated expanded polyethylene foam with a density of 30 Kg/m³, and a 2 mm thick intermediate acoustic barrier layer in EPDM with a density of 4 Kg/m³. The special structure of the FONECOdBAM panel, which measures 7 mm thick in all, reduces noise emissions to a value of 25 decibels, certified by the Italian CSI institute.

The contribution of the wall and/or of a specific liner applied to the drainage system

Laboratory tests conducted on drainage systems also certify the noise levels measured directly from the drainage system itself with no wall acting as a barrier. It is interesting to note that, in this test scenario, there is no product on sale today that can guarantee compliance with the 35 dB limit imposed by DPCM 5/12/1997 in all possible construction situations. As a consequence, the type of wall the system is installed on and the type of lining necessary must be carefully considered and evaluated to attain compliance. 
(Table) To ensure an adequate safety margin and allow for installation error, in addition to using a soundproofed drainage system, the wall must also contribute to noise abatement by at least 20-25 dB. This degree of noise abatement is possible with a solid, soundly built wall consisting of 80 mm thick plastered brickwork, or of a double layer of plasterboard.