RESIDENTIAL NOISE ASSESSMENT BS8233

Planning applications for new residential developments, whether they be new builds or change of use conversions, may require a noise impact assessment be carried out to show that habitable rooms can achieve the BS8233 noise assessment and World Health Organisation recommended indoor ambient noise levels. For these assessments, planning and design work begins with a noise survey to determine the existing noise climate at the site. The measured noise levels are then used to determine the required sound insulation performance of the building envelope, including glazing.

 

Specifications and ventilation strategy options. With the introduction of building regulation Approved Document O in 2022, it is now also important to consider the overheating strategy for new build residential developments and what affect it might have on internal noise levels within bedrooms during the night-time period, as criteria for noise levels in bedrooms at night are included within the new building regulations. This is particularly important for proposed developments in London, where the overheating requirements can be more onerous in conjunction with higher external noise levels being more widespread across the city. It is therefore important to seek advice from an acoustic consultant based in London, that has experience with residential noise impact assessments and who’s input can be aligned with the ventilation and cooling strategy regarding the noise level requirements of Approved Document O.

​

The local authority may require a noise impact assessment if the proposed residential site is exposed to transportation noise such as noise from road traffic, rail or aircraft noise, or noise from existing noise producing commercial or industrial uses close to the site. These types of planning conditions often refer to BS8233 noise assessment for transportation noise sources, or BS4142 for commercial and industrial noise sources, when setting out the requirements which the BS8233 noise assessment should aim to address. In some cases, a planning condition may also specifically state that the indoor noise levels must be considered during times that windows are open to mitigate overheating. If a proposed residential dwelling is located next to an adjoining commercial premises via a separating wall or floor, then a planning condition may also be set regarding the sound insulation performance of the separating construction, where criteria of 5dB or 10dB above the standard Approved Document E performance standards may be set, or for commercial noise ingress to be 5dB or 10dB below the BS8233 noise assessment recommended internal noise levels for dwellings. With different types of noise assessment planning conditions varying significantly between different local councils, it is important to use an acoustic consultant with a good understanding of the various acoustic standards and guidance, so that the planning authority’s requirements are addressed in the right way.

​

The process of a residential noise assessment typically involves both a noise survey and a noise assessment to inform the necessary design approach. Once the planning requirements have been reviewed, a noise survey is typically carried out at the site to determine the existing environmental noise levels. Microphones are usually positioned at the proposed residential façade locations and left on site to survey noise levels over a period of a few days. Once the noise survey is completed, the data is then processed to be used as part of the noise impact assessment. Where the proposed residential development is located next to an adjoining commercial premises, a sound insulation test may be carried out on the separating wall or floor to determine the existing performance. The noise survey data is then used as part of the BS8233 noise assessment to determine the required specification of the façade constructions and details, as well as the ventilation strategy and design, in on order to achieve the planning condition requirements. Where the proposed residential development is located next to an adjoining commercial premises, an assessment may be carried out

to determine the sound insulation performance of the separating constructions, and or, commercial noise ingress to the proposed dwellings, with the necessary acoustic upgrades recommended where necessary.

​

Once all the above stages have been completed, a noise impact assessment report will be produced. The noise impact assessment report would include details of the proposed site, planning condition requirements and relevant acoustic standards and guidance, methodology and result of the noise survey and acoustic testing, and proposed noise control and acoustic design measures necessary to meet the local authority requirements. Our goal is always to produce clearly written and structured reports, which can be understood by our clients whilst also being technically robust and suitable for submission to local planning authority, with the aim of discharging noise and acoustic related planning conditions as quickly and sufficiently as possible.