3. Performance of underlays based on acoustics
As a rule, underlays have an impact on the acoustic properties of floor covering modules.
Performance characteristic:
IS: impact sound reduction
Impact sound is defined as the noise which is perceived in the room below or next to the floor covering system. The noise can be generated by footsteps, falling objects etc.
The IS value is the reduction of noise generated on the same subfloor with and without the floor covering.
The underlay must be tested in combination with the floor covering as simple extrapolation of underlay and floor covering is impossible.
The higher the IS value, the better the underlay – in combination with the floor covering –will reduce the transmission noise.
The floor covering has a significant influence on the IS value of the flooring system. It has to be declared if testing the system was done with reference to a group 1 floor, based on a HDF core, and/or if it was done with reference to a group 2 floor, using an LVT core. Therefore ISHDF for underlay group 1 (as described in EN 16354) and/or ISLVT for underlay group 2 (as described in EN 16354) have to be declared.
RWS: radiated walking sound reduction
Walking sound is understood as the noise that is heard when the floor covering inside the room itself is used (e.g. when walking over it, playing on it, etc.). On the basis of EN 16205 especially for laminate floor coverings a test method was developed that can evaluate the “perceived loudness” of a floor covering with the RWS-value.
Hints: The value of Ln, walk, A described in the current state of EN 16205 is only partially correlating with the perceived loudness. – Reference-value under development
The lower the RWS value, the better the underlayment will reduce the emission of walking noise.
The floor covering has a significant influence on the RWS value of the flooring system. It has to be declared if testing the system was done with reference to a group 1 floor, based on a HDF core, and/or if it was done with reference to a group 2 floor, using an LVT core. Therefore RWSHDF (see A1.7.1) and/or RWSLVT (see A.1.7.2) have to be declared.
