About PPG24 Noise Assessments & Noise Surveys
(Planning Policy Guidance 24)
Planning policy guidance (PPG24) notes set out the Government policies on different aspects of planning. It is regularly used by Local Authorities in order to place noise based planning conditions on potentially noisy residential sites. If required, property developers have noise surveys carried out in order to show that on-site noise levels are compliant with this document for the planning application to be accepted.
PPG24 Noise Assessments and PPG24 Noise surveys are for planning applications of both small and large developments. Normally requested by a Planning Officer/Local Authority due to concerns relating to construction of new residential dwellings (or change of use) in a high noise exposure area. More often than not it’s in relation to new build apartments, houses, or hotels.
New dwellings can be exposed to road traffic, rail, air or mechanical/commercial noise that is unacceptable. A 24 hour (longer may be required) noise test is usually conducted in order to determine the Noise Exposure Category (NEC) that the proposed property would fall into (A, B, C or D).
PPG24 requires a noise survey to be conducted at the planning stage to assess the overall suitability of the site's noise climate for residential development. With it comes the possibility of noise control measures being necessary as part of the planning conditions.
Advice is given on how the planning system can be used to minimise the adverse impact of noise without placing unreasonable restrictions on development. This particularly relates to people when they are in buildings such as the home, educational establishments and hospitals.
Development Control and Planning Conditions
The PPG24 document sets out general guidelines, for example:
- Not to place unjustifiable obstacles in the way of development
- Consider the existing noise levels and any increase that may reasonably be expected in the foreseeable future
- Some sites will be significantly quieter at night, whereas at other sites background noise may not reduce very much because of heavy traffic flow
Conditions should satisfy the usual general planning requirements. They can be used to limit noise levels or specify noise mitigation measures and/or sound insulation measures for buildings etc.
Measurement Positions
To carry out measurements the Sound Level Meter is placed at least 3.5m from any reflecting surface (buildings) etc, and between 1.2m and 1.5m above ground.
Noise Assessment Process
A class 1 (or Type 1) Sound Level Meter and environmental kit is positioned on site.
Broadband and single octave analysis occurs during the monitoring period.
Broadband measurements logarithmically formulate daytime 0700 - 2300 hours (LAeq, 16h) and night time 2300 - 0700 hours (LAeq, 8h).
The broadband dB LAeq levels are classified within a Noise Exposure Category (NEC) A, B, C or D