Living in harmony – considering the impact of entertainment noise sources for planning applications

Housing demand in the UK continues to outpace supply with ongoing population growth in the cities. People want access to amenities on their doorstep, but still need a comfortable space to work, relax and sleep.

This results in new residential dwellings appearing in areas previously used for very different uses, including music venues, cinemas, nightclubs and bars.

Planning requirements

Under the National Planning Policy Framework (NPPF), the person or business (the agent) introducing a new land use is responsible for managing the impact of that change. This is known as the ‘Agent of Change’ principal and it was introduced as part of the July 2018 revisions to the NPPF, following consultation on the original issue of the document.

For new residential or noise sensitive uses being introduced adjacent to an existing premises, the NPPF states:

‘Existing businesses and facilities should not have unreasonable restrictions placed on them as a result of development permitted after they were established. Where the operation of an existing business or community facility could have a significant adverse effect on new development (including changes of use) in its vicinity, the applicant (or ‘agent of change’) should be required to provide suitable mitigation before the development has been completed.’

For a new source of entertainment noise moving into a noise sensitive area, the NPPF states:

‘Planning policies and decisions should also ensure that new development is appropriate for its location taking into account the likely effects (including cumulative effects) of pollution on health, living conditions and the natural environment, as well as the potential sensitivity of the site or the wider area to impacts that could arise from the development. In doing so they should:

a) mitigate and reduce to a minimum potential adverse impacts resulting from noise from new development – and avoid noise giving rise to significant adverse impacts on health and the quality of life…’

Whilst the NPPF defines the responsibility of the developer, or ‘Agent’, its scope does not extend to providing specific criteria against which impacts can be assessed.

Current guidance on assessment

The assessment of entertainment noise impact is dependent on the context, with one set of criteria not being suitable for all situations. It is important that suitable criteria are agreed between the developer and Local Planning Authority early on. This is to allow mitigation strategies to be developed and incorporated into the scheme, as these can have significant design implications.

There are no British Standards relating to the assessment of music noise. British Standard BS 4142:2014 ‘Methods for rating and assessing industrial and commercial sound’ specifically excludes noise from ‘music and other entertainment’ as well as ‘people’ from its scope. BS 8233:2014 ‘Guidance on sound insulation and noise reduction for buildings’ recommends internal noise criteria for residential dwellings but states that they apply to ‘sources without a specific character’. It goes on to note that where noise is ‘distinguishable, discrete and continuous tone, is irregular enough to attract attention, or has strong low-frequency content’ lower noise limits might be more appropriate.

In the absence of guidance, many local authorities have derived their own criteria relating to entertainment and music noise, with many including subjective assessment terms such as ‘inaudible’ within their wordings.

The most widely referred to document is the Good Practice Guide on the Control of Noise from Pubs and Clubs (2003) produced by the Institute of Acoustics (IOA). Whilst not providing objective criteria, it suggests that for premises where entertainment takes place on a regular basis, music and associated sources should not be audible inside noise-sensitive properties at any time.

To promote further debate, a separate article was published in the IOA Acoustics Bulletin Nov/Dec 2003. This article does provide criteria for assessing entertainment noise, and takes into consideration the annual and weekly frequency of events:

This assessment method looks at the ‘equivalent average’ noise levels (LAeq) generated by the entertainment use, and compares to the ‘background’ sound level (LA90). The equivalent average noise level can be considered to be the typical noise level generated by the entertainment use. The background sound level can be considered the underlying noise level at the receptors in the absence of entertainment noise, representing the quietest 10% of the measurement period.

Whilst the above criteria are likely to provide reasonable control of noise, there are two limitations. Firstly, it will not ensure inaudibility within the dwellings at upper frequencies, and secondly, at lower frequencies, background noise levels have the potential to be significantly lower than the threshold of audibility, resulting in a requirement to overly attenuate music levels.

All about the bass

Whilst entertainment noise sources can vary, the impact of low frequency noise (bass) from a variety of sources is a common complaint. This arises due to the difficulty in attenuating low frequency noise, along with the relatively poor low frequency sound insulation performance of typical glazing. Age induced hearing loss can also result in a higher sensitivity to low frequency noise, as a result of reduced sensitive at upper frequencies.

Defra research undertaken by the University of Salford (NANR45) has produced criteria for assessing the impact of low frequency noise on dwellings. While developed for steady continuous noise sources, they are considered a reasonable standard for designing new developments affected by entertainment noise. These are presented below, alongside a typical threshold for audibility curve.

Whilst potentially not guaranteeing inaudibility in all cases, adopting absolute levels provides planning departments, designers and developers with clear criteria, free of the ambiguity of subjective descriptions such as ‘inaudible’.

Typical mitigation

Once suitable criteria have been established to protect residents against the impact of entertainment and music noise, consideration needs to be given to how those limits will be achieved.

Where a new venue is to be introduced within a residential area, the most effective solution is to ensure the building shell is designed to control noise breakout to suitable levels. A detailed assessment of noise breakout from all potential paths will need to be undertaken. This includes assessing all the facade elements and roof constructions (if applicable), as well as any ventilation paths.

Where new residential dwellings are proposed near to an existing entertainment noise source, providing enhancements to the existing venues may not be practicable; however, it is possible through an appropriate Section 106 agreement. This is an obligation attached to the planning permission whereby the contractor agrees to provide funds for mitigation measures, usually in the form of enhancements to the building shell of the venue.

Where this isn’t an option, mitigation to the residential premises, in the form of enhanced facades and glazing specifications may be considered. If entertainment noise levels are particularly high, it may also be necessary to alter building massing to screen noise sensitive areas, reduce window areas, and relocate noise sensitive spaces to quieter facades.

Ventilation and overheating also need to be considered. Traditionally, control of overheating would be provided by opening a window. There are obvious problems with this in noisy locations, as depending on how much a window is opened, this can reduce the overall sound insulation achieved by the facade to as little as 4 dB in some cases.

Where closed windows are needed to mitigate noise, consideration needs to be given to how the space will be ventilated and how overheating will be controlled. It is important that an overheating assessment (often a CIBSE TM59 assessment) is undertaken at an early stage. This is to determine what ventilation and overheating control systems are needed as these can have a significant impact on other elements such as building height and windows sizing, all of which typically need to be agreed at the planning stage.

If your noise source is within the same building or in an adjacent structurally attached building, in addition to noise break in via the facade, consideration also needs to be given noise transfer via the separating structure.

The importance of early assessment

It is important to realise that there is a limit to the level of separation that can be achieved by either a facade or a separating wall or floor, both in terms of structural practicability, and also cost implications that can affect the viability of a development.

Noise surveys can sometimes be considered a ‘box ticking exercise’. However, the identification of entertainment noise affecting a site can have a significant impact on not only the viability of a scheme, but also on the design of the proposed development.

Carrying out an early assessment of entertainment noise, agreeing suitable criteria between all relevant parties and implementing suitable mitigation is vital for delivering a high-quality scheme.

By Anthony Harper
BSc, MIOA