Introduction

This guidance has been developed in response to Planning Advice Note (PAN) 1/2011 and should be read in conjunction with this document and the accompanying Technical Advice Note (TAN). It takes into account current policy in relation to planning and noise and provides guidance on undertaking noise assessments which may be required for any potential development in determining planning applications.

Where noise is a consideration in a planning application, planning officers consult with the area Environmental Health Officer (EHO). The EHO will advise whether a noise impact assessment (NIA) is required and review any noise information submitted by the applicant. The EHO will need to consider whether the information provided is sufficient to accurately assess the noise impact of the proposed development.

Pre-planning discussions with the EHO are very useful for determining the risk of noise being a significant consideration and identifying the supporting information and detail on noise likely to be required. This can save delays in the planning process.

When noise should be considered in the planning process

There are two types of development for which noise impact assessments will be required:

• Proposed Noise Generating Development (NGD) where noise is brought to people
• Proposed Noise Sensitive Development (NSD) where people are brought to existing noise.

Where it is not possible to separate noisy and noise-sensitive land uses, developers will have to incorporate good acoustic design and a sensitive approach to any new development proposals.

Where areas already have an unacceptable noise level it may not be possible to mitigate the adverse effects of noise. In such circumstances, noise-sensitive development may not be appropriate. In some cases, there is a need to protect existing commerce and industry from complaints from residents of new housing developments.

Noise Policy

Scottish Government policy on noise

The Environmental Noise (Scotland) Regulations 2006 required the production of strategic noise maps for large urban areas, transport corridors, and large airports within Scotland. From these strategic maps, action plans were drawn up which identified areas where residents were likely to be exposed to the highest noise levels.

These areas are known as Noise Management Areas (NMAs). These action plans also identified areas where individuals were likely to experience relatively low levels of noise, known as Quiet Areas (QAs).

The Scottish Government Action Plans aim to identify noise abatement measures designed to manage avoid, prevent, or reduce the harmful effects of noise exposure in NMAs and to maintain and protect environmental noise quality in QAs. 

Council policy and guidelines

Under planning legislation councils must produce a local plan, setting out their detailed policies and proposals for the use, development, protection, and improvement of land.

Like the Scottish Government's responsibilities, councils should ensure through the planning process that new development does not result in increasing numbers of people exposed to adverse noise impacts in both NMAs and QAs.

Noise Assessment and Methodology

Before undertaking an assessment, an agreement is required to be reached between developers and the council on all relevant noise-generating sources and noise-sensitive receptors (NSRs), methodology of assessment, and noise targets. These details should be confirmed in writing.

Where a NIA is required it must be undertaken by a suitably qualified and competent person. Noise reports need to be comprehensive and include enough information for the council to assess the likely noise impact of the proposed development. If enough detail is not provided in terms of the methodology and calculations then there could be a delay in the planning process. Usually, noise measurements will need to be taken to establish the noise environment at the site of the proposed development. Noise monitoring should be carried out in accordance with British Standard BS 7445-1:2003

Any assumptions used in the prediction of noise levels must be clearly stated in the noise report. The submitted report must also provide a sample calculation to demonstrate how the noise figures have been obtained. Detailed raw data must be made available on request.

Wind turbine noise is covered in separate guidance.

The following table outlines the relevant assessment methodology and target noise levels for the most common noise sources.

Notes:

1. Noise monitoring should be carried out in accordance with BS 7445-1:2003
2. New commercial developments where amplified music or any broadcasting is a likely activity should be designed to ensure that this noise is contained within the development boundary.

Where NSD is being brought to an existing noise source developers will need to demonstrate that all mitigation methods have been considered to achieve satisfactory internal noise levels within any noise sensitive property and protect external amenity areas.

Only in exceptional circumstances should satisfactory internal noise levels only be achievable with windows closed and other means of ventilation provided. Predictions of internal noise levels within noise-sensitive premises must be calculated based on an open window scenario. The degree of sound reduction afforded by a partially open window should be taken as 13dB (as calculated from the façade level).

For the purposes of this guidance exceptional circumstances are considered to be proposals which aim to promote sustainable development and transport within the council area and which would provide benefits such as

• reducing urban sprawl
• reducing uptake of greenfield sites
• promoting higher levels of density near transport hubsm town and local centres
• meeting specific needs identified in teh local development plan

Exceptional circumstances will, therefore, generally only apply to sites which are small to medium in scale, within urban area. This may include sites in established residential areas, brownfield sites, town and village centres and sites near public transport hubs.

It should be noted that the Scottish Environment Protection Agency (SEPA) regulate noise from certain industrial processes. Despite this regulatory role by SEPA, the council will decide whether any noise impact on residential development from such industrial processes is significant. Liaison between SEPA and the council must be undertaken in these cases.

Determining the magnitude of noise impact

For steady continuous noise the World Health Organisation document "Guidelines for Community Noise" (1999) recommends an indoor guideline value for bedrooms of 30dB LAQ (8h), to prevent sleep disturbance and 45 dB LAmax for single sound event. However, the document WHO NNGE 2009, which is an extension of the previous guidance recommends that the single event noise level (the noise level below which there are no observed effects) is reduced to 42 dB LAmax to protect occupants from sleep disturbance. WHO Guidelines for Community Noise further recommends a daytime level below 50 dB LAeq(16h) on balconies, terraces and outdoor living areas to protect receptors from moderate annoyance. WHO also indicates that at an outdoor, daytime level below 55 dB LAeq(16h) will protect the majority of people from being seriously annoyed. Therefore levels predicted to be above 55 dB LAeq(16h) are likely to have a major impact.

Qualitative Assessment

After the quantitative determination of the magnitude of noise impact, a qualitative assessment should be undertaken to assess the effect on the amenity value of the existing or proposed noise sensitive receptor. The qualitative assessment will either confirm the quantitative assessment is satisfactory or will indicate that additional factors need to be taken into account when describing the magnitude of impact. The additional factors to be taken into account will depend on the type of noise sensitive receptor eg. the potential for sleep disturbance, effects on ability to relax concentrate or converse or use of outdoor space. Examples of descriptors for qualitative impact of noise are given in the document Technical Advice Note : Assessment of Noise (TAN).

Once the magnitude of noise impact has been appropriately described, the level of significance f the impact can be determined. The significance of the impact will depend on the sensitivity of the existing or proposed noise receptor(s). TAN advises that noise assessments should include a Summary Table of Significance to show the number of NSRs likely to be subjected to significant noise impacts. Although the overall number of NSRs  which will be affected is obviously important, the EHO reviewing the NIA will also pay heed to the effect on individuals. A large negative noise impact on any one individual NSR will be of concern to the EHO and this will be reflected in the advice the EHO gives back to the planning officer.

Sometimes it may also be appropriate to consider the cumulative impact of the proposed development. This could be when other developments in the surrounding area have already received planning consent but have not yet been completed. The developer and their noise consultant should discuss this with the EHO and planning officer during the pre-planning discussions.

The NIA should give details of any mitigation measures that would be necessary to achieve satisfactory target noise levels.