Planning Policy Guidance 24 was first published in 1994 and has now been replaced by the National Policy Planning Framework. Previously it offered outline advice for councils.

PPG 24 introduced the concept of Noise Exposure Categories (NEC’s) which are still referred to my some councils as part of local planning.

Noise Exposure Categories A-D

A – Noise need not be taken as a determining factor in granting planning permission, although the noise level at the high end of the category should not be regarded as a desirable level.

B – Noise should be taken into account when determining planning applications and, where appropriate, conditions imposed to ensure an adequate level of protection against noise.

C – Planning permission should not normally be granted. Where it is considered that permission should be given, for example because there are no alternative sites available, conditions should be imposed to ensure a commensurate level of protection against noise.

D – Planning Permission should normally be refused.