What is ProPG?
Professional Practice Guidance: Planning & Noise (ProPG) is a document which was published in 2017 by the Association of Noise Consultants (ANC), Institute of Acoustics (IOA) and the Chartered Institute of Environmental Health (CIEH).
The current Government planning, noise policy and guidance provides clear objectives, however it does not define a prescriptive method to assess the suitability of new residential dwellings in England.
ProPG aims to provide guidance on noise during the planning stage for new residential dwellings and provides a standardised approach to assess the suitability. It also outlines good acoustic design principles for residential developments and promotes the inclusion of these principles where possible.
Who is it for?
The document is intended to be used by acoustic consultants when assessing a site’s suitability for residential development. It could also be used for reference by local authorities, who may request that assessments be undertaken in accordance with ProPG, in order to determine whether a scheme is suitable for residential development. At the time of writing, the guidance appears to have been adopted by several local authorities across the country.
What has it replaced?
Since 2012, the only guidance provided to Local Authorities was included in the National Planning Policy Framework (NPPF). Although ProPG does not replace guidance within NPPF, it does significantly expand on the noise policies in NPPF.
Prior to 2012, Planning Policy Guidance 24: Planning and Noise (PPG24) guided local authorities in England on assessing the suitability of new residential sites. This document gave a prescriptive method for assessing the site’s suitability, however it did not account for the inclusion of good acoustic design, which could mean that a residential scheme is suitable for development. One of the strengths of ProPG is that it allows the acoustic consultant and local authority flexibility to take a holistic approach to consider the site’s suitability, taking into consideration various design factors which previously may not have been considered.
A new key concept here is that good acoustic design should still be followed if necessary even if the site is quiet, and conversely, through good acoustic design it may be possible to design suitable residential dwellings in areas which experience high noise levels.
The basic principles
The first step in a ProPG assessment is to measure noise levels around the site and to understand the noise climate.
Once a noise survey has been completed, ProPG sets out various assessment ‘routes’ which are dependent on how high noise levels are around the site. It’s important to note that the advice provided in ProPG is generally applicable to transport noise, and should not be used to assess industrial noise. In such cases, BS4142:2014 should be referred to.
Negligible Risk Sites
Generally if the measured noise levels are below 50dB LAeq,16hours during the day and 40dB LAeq,8hours at night then it is unlikely that any further detailed assessment would be necessary, as the site likely to be suitable.
Low Risk Sites
Where noise levels are below 60dB LAeq,16hours during the day and 50dB LAeq,8hours at night, then the site is likely to be classed as ‘low risk’. In such situations, it may be necessary to prepare an Acoustic Design Statement (ADS) to demonstrate that good acoustic design of the scheme will allow the site to be suitable for development.
Medium & High Risk Sites
If noise levels are above 60dB LAeq,16hours during the day and 50dB LAeq,8hours at night, then the site could be classed as ‘medium risk’ or ‘high risk’. If this is the case then it likely that a detailed ADS will be required, which will review various design elements and potentially fundamentally affect the building’s orientation, layout and other design features. The impact of altering the scheme for acoustic purposes would then need to be reviewed by the design team to see if such changes could be made, while still resulting in a feasible design overall.
One of the most critical aspects of implementing good acoustic design is to ensure that an acoustic consultant is engaged as early in the design as possible, and ideally at the concept stage. If engaged too late, it may not be possible to alter the building’s design sufficiently to demonstrate that good acoustic conditions can be achieved throughout the development, which could ultimately result in planning permission for the development being conditioned or refused on the grounds of noise.
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