The value of the acoustic targets must of course comply with the regulations in force. Those will typically cover the following items:
• Sound insulation with regards to the outside environment; the fagade sound insulation value is typically set to limit the background noise level inside the living spaces (bedroom, living room) to the 30 to 35 dB(A) range.
• Sound insulation with regards to other spaces within the building (i.e., other dwellings, activity room, parking, etc.); the sound insulation value in terms of DnTw is typically in the range 50 to 60 dB.
• Sound insulation within a flat or house usually is not a legal requirement, though it may be recommended by some high-quality standards (e.g., ).
• Impact sound transmitted from other spaces; the impact noise in terms of L’nTw is typically in the range 50 to 60 dB.
• Reverberation control usually is not required within the dwelling proper. But several regulations require it for noise control inside common spaces, on the one hand, and for the comfort of hearing-impaired people, on the other hand (e.g., ); typically an equivalent absorptive area amounting to 25% of the floor area is required for corridors or waiting areas.
• Noise from mechanical equipment of the building; first, there is a distinction made between the common equipment of the building (e.g., boiler, lift) and the individual equipment of the dwelling (e.g., air conditioner). The former must not generate in the l iving spaces a sound level value greater than, typically, 30 dB(A), while the latter typically is allowed a higher value inside the dwelling where it is located. Next, there usually is a distinction made between permanently operating equipment (e.g., used air extraction) and random used equipment, which typically is permitted a 3 to 5 dB higher noise level.
• It is not unusual for some high standard dwellings to feature some unusual (as far as regulations are concerned) spaces and pieces of equipment. While home cinema facilities now appear, there also are music rooms, sport rooms, Jacuzzis, and even swimming pools (cf. Section 8.5.11) to contend with. Such spaces must be studied on a case-by-case basis, with required data to be provided by the client or the manufacturer (e.g., noise levels likely to be produced, periods of use, sound power level of the equipment of interest, velocity levels likely to be produced in a concrete slab similar to the floors of the project, etc.). Only then will the sound insulation, impact insulation, and sound power level targets be defined in order to comply with the applicable regulations (and possibly with the condominium rules in force too).