BS 8233:1999 Sound insulation and noise reduction for buildings

BS 8233 deals with the control of noise from outside the building, noise from plant and services within it, and room acoustics for non-critical situations. It is a code of practice that is intended for use by non-specialist designers and constructors of buildings and those concerned with building control, planning and environmental health. The code suggests appropriate criteria and limits for different situations. These criteria and limits are primarily intended to guide the design of new or refurbished buildings undergoing a change of use.

Ambient noise levels

Table 5 of BS8233 presents recommended indoor ambient noise levels for different situations. Table 8 is an extract of the guidance relating to offices from Table 5 of BS8233.

Table 8:Indoor ambient noise levels in spaces when they are unoccupied(From BS8233)

Privacy in offices

Privacy between offices and between an office and an occupied space requires good sound insulation and moderate background noise to mask intruding speech.

The guidance given in BS 8233 is:

The minimum acceptable sound insulation between two cellular offices is as about D_w = 38 dB. Where privacy is important the minimum sound insulation should be D_w = 48 dB although even then it is possible that voices will be heard, but the conversation will not usually be understood. Where the indoor ambient noise level is low it may be necessary to design for higher insulation values. As a rough guide, speech will be audible but not intelligible if D_w + L_A > 75, where D_w is the weighted level difference between rooms, and L_A is the indoor ambient noise level in the room. If demountable partitions are used to form cellular offices, it is likely that the sound insulation will be lower than is desirable for good privacy.