Using pallet trucks early in the morning or late at night won’t create nuisance to the occupants of this brand new building thanks to the application of a CDM-MAT isolation layer under the floating floors.
In some multi-functional buildings, supermarkets are located under an apartment block which, if not isolated, may cause serious noise nuisance for the occupants. In particular, the rolling noise of pallet trucks is clearly audible as it is easily transmitted via the floor and as most of the loading and unloading activities are planned early in the morning or late in the evening, when background noise levels are very low, this is obviously of particular concern when designing the building. The main strategy of acousticians and architects to prevent this kind of noise nuisance is to decouple the entire floor of the supermarket and unloading areas by using a continuous mat isolation solution.
For the Delhaize project about 3000 m² of floor have been decoupled by using a resilient recycled rubber mat with a wavy surface (CDM-MAT). In critical zones like the unloading area the applied mat solution was adapted to provide extra acoustic isolation. A floating reinforced concrete floor was then installed on top of the mat. Lateral decoupling of the loadbearing walls, columns, and services running through the floor was achieved by using CDM-PERIMETER strips which were meticulously installed to avoid all possible bridging.
CDM specifically developed for rolling noise isolation applications a full range of wavy surface mats (CDM-MAT), based on DLv,rn index. This new concept is used in France and based on an extended frequency range of 50 to 500 Hz, for better evaluation of the low frequency response and performance. The CDM-MAT has a profiled underside thereby minimizing contact points across the floor and reducing the structure-borne noise transmission to the supporting structure of the building whilst still providing a low resonance frequency for the floor system. The high density of the chosen CDM-MAT means a long-term warranty of the physical and acoustic performance of the system can be provided as the effects of creep are of no importance. Low density resilient mats are known to suffer from creep leading to reductions in elasticity and noise isolation performance in the long term.