Facade sound insulation comfort criteria in European classification schemes for dwellings

Acoustic classification schemes for dwellings exist in 9 countries in Europe. The schemes specify class criteria concerning several acoustic aspects, the main criteria being about airborne and impact sound insulation between dwellings, airborne sound insulation of facades and noise from building services and equipment. The different classes in the classification schemes are intended to reflect different levels of acoustical comfort.
There are significant discrepancies between the European schemes, among these descriptors, number of quality classes, intervals between classes, levels of classes and the status of the classification schemes in relation to the legal requirements. In some countries the building code and the classification standard are incoherent. In other countries they are strongly "integrated", implying that the building code refers to a specific class in the classification standard rather than describing the requirements.
The paper describes the facade sound insulation descriptors applied in the European schemes. The Nordic schemes specify max indoor equivalent A-weighted levels, other countries specify the sound insulation as a function of the outdoor level, applying ISO 717 descriptors. None of the schemes apply directly the harmonized environmental noise indicators Lden and Lnight defined in Environmental Noise Directive (2002) for description of annoyance and sleep disturbance, respectively, or psychoacoustic descriptors.