Background
Anderson Acoustics was commissioned by Barry Davis and Sophie Moon to undertake a noise assessment in support of a planning application for the redevelopment of “Gilridge”, Brighton Road, Handcross, RH17 6BZ to provide 4 new dwellings across 2 adjacent plots.
The site is in close vicinity to the A23, a major road between London and Brighton, and as such the Environmental Protection team in the Mid Sussex District Council placed extra scrutiny on the principles of good acoustic design including the ventilation strategy options for this development.
What we did
BS 8233:2014 Guidance on sound insulation and noise reduction for buildings is the most relevant Standard in terms of noise and the scope of our assessment.
External amenity spaces are an intrinsic part of the overall design, so consideration of the need to provide access to a quiet or relatively quiet external amenity space forms part of a good acoustic design process as is the case for this development.
Environmental noise survey
We undertook a detailed environmental noise survey on site to assist in the assessment of the sound reduction performance specifications for glazing, ventilation, and external wall constructions; as well as to predict noise levels in the external amenity areas of the scheme.
Computer Modelling
The Council required computer modelling to be produced which shows the impact of the recommended design measures. To predict the impact of road noise across the development site, we used the baseline noise measurement results to produce a detailed 3D environmental noise model. The predictions were carried out using the noise-modelling suite Cadna/A 2023, which allow consideration of the effects of the acoustic screening provided by both existing buildings surrounding the site and buildings of the development itself.
The results of the noise modelling were used to determine the likely noise levels incident on each building across the completed site. These predictions have formed the basis of the mitigation proposals. In addition to the road source noise levels used in the predictions, the model considers the effects of the topographical conditions throughout the area, ground absorption, atmospheric absorption, acoustic reflections, and acoustic screening.
Good acoustic design measures
We proposed additional design measures including:-
- the introduction of a 2.7m high solid acoustic barrier to reduce the noise impact on private amenity areas, impact to be partially offset with the provision of quieter publicly accessible parks in the immediate vicinity of the site including the Nymans National Trust site.
- external pergola structures to provide solar shading and alternative cooling strategies.
Project Progress
We recommended that, with regard to noise, planning consent should be granted subject to the inclusion of suitable noise conditions.
Planning was granted permission by Mid Sussex District Council in August 2024.
Input from other disciplines (e.g., M&E, energy/thermal consultants) will now be required to provide detailed construction specifications during the detailed design stages.
