Provides design criteria for conditions affecting the acoustic environment within occupied spaces. The ambient sound levels take into account the function of the area(s) and apply to the sound level measured with the space unoccupied but ready for occupancy.

This standard sets out design criteria for conditions affecting the acoustic environment within occupied spaces. The ambient sound levels recommended take into account the function of the area(s) and apply to the sound level measured with the space unoccupied but ready for occupancy (see Note 1). The standard is applicable to steady-state or quasi-steady-state sounds, such as noise from air-conditioning systems, and noise from continuous road traffic. The reverberation times recommended are for the occupied state of the enclosure.NOTES:1. The sound level during occupancy will usually be increased owing to the activities of the occupants.2. For auditoriums or studios, exclusion of sound other than that of the performance is vital for the successful operation of the space. In other areas, the level of ambient sound may affect speech communication or, in extreme conditions, the effectiveness of a public address system. Control of the ambient sound level is required to achieve good communications. On the other hand, spaces such as offices and restaurants may benefit from some continuous ambient sound, which may assist in providing privacy between adjacent groups of people or in reducing distraction where people are concentrating on some particular task.3. This standard does not exclude a current practice, where, for the purpose of acoustic masking, continuous ambient sound may be deliberately introduced at a particular level. Conditions affecting the use of acoustic masking are given in Clause 8.4. For buildings located near airports, reference should be made to AS 2021.

Under Revision see DR 99367