This section deals with current UK assessment criteria for planning. It has little international relevance. The main document, PPG24 [click here to download] considers two separate circumstances:
Naturally it is important for industrial and commercial concerns to understand how the noise impact of their proposals will be assessed; it is also important for these same concerns to understand some of the processes involved when assessing the impact of their noise, on proposed housing etc. It may be thought that "if the Council is daft enough to grant consent for the housing, then any noise problems are either the Council's or the people who bought the houses next to the noise". However, the law takes the view that in any nuisance action it is no defence to say that the residents moved next to the noise; equally it may be that the Council could be enjoined in an action to pay for resolving the noise problem, but this is by no means certain. In general it is far better for potential problems to be identified as early as possible.
The main planning document is Planning Policy Guidance Note 24 "Planning and Noise".
"New" Noise in Existing Areas
PPG24 - "New" Housing in Existing Areas
Transportation Noise Affected Proposed Housing
A - Noise need not be considered a determining factor in granting consent.
B - Planning Authorities should increasingly take noise into account and require noise control measures, i.e. noise is an important factor but not of over-riding importance.
C - There should be a strong presumption against permitting the development, unless there are other important factors, such as a lack of better alternative sites.
D - Planning permission should normally be refused.
These Noise Exposure Categories are defined in terms of the LAeq averaged separately over the night-time [23.00-07.00] and daytime periods [07.00-23.00]. The daytime and night-time categories can differ, and the "worst" NEC is selected.
The NECs vary depending on the source of the noise. The table of all the
various noise exposure categories is shown below:
It should be noted that paragraph 9 of PPG24 enables the
boundaries of NECs to be altered by up to 3 dB “For example,
where there is a clear need for new residential development in
an already noisy area some or all NECs might be increased by up
to 3 dB(A) above the recommended levels. In other cases, a
reduction of up to 3 dB(A) may be justified”.
Finally PPG24 makes recommendations regarding suitable external noise levels on the basis that a house built in that location would have acceptable internal noise levels.
If, having read the above and the standards, you don't feel competent you can consult the Directory for a list of consultants.