Noise and Brownfield Development

A core part of our business at Dragonfly Acoustics is noise assessments in support of planning applications. In the majority of cases these devlopments are now on brownfield sites, often in built up or urban areas.

When undertaking an assessment in support of an application for a residential development in these areas, as for any noise assessment in support of a planning application, we follow the guidance in Planning Policy Guidance 24: Planning and Noise often referred to as PPG24.

Categorising a Site

As part of an assessment PPG24 requires we ‘categorise’ a site according to the daytime and night time ambient noise levels. These 4 categories ranging from A to D encompass the whole range of sites with ‘A’ indicating noise is not an issue on a site and ‘D’ indicating that “Planning permission should normally be refused”. (For the full list of PPG24 categories, please see datasheet below)

It is not unusual for the majority of town and city centre Brownfield Development sites to fall into PPG24 categories C and D, which broadly guides that development of these sites should be prohibited or at best avoided where possible. Our clients often ask us “what does this mean for our site”.

The Background to PPG24

PPG24, which was originally published in 1994, is becoming ever more out of step with government policy, in particular policy promoting the regeneration of existing Brownfield sites in our towns and cities. PPG24’s replacement PPS24 was originally due to be published by late 2007, 3 years later, after the consultation process for this document stalled we are still no closer to it being published.

For a town or city centre site that falls in category A or B the development will normally see little resistance from the planning authority with respect to noise. Category C or D sites will create some concern with the planning authority and they will want the applicant to demonstrate that a suitable noise environment can be achieved in the proposed homes.

Addressing Local Authority Concerns

In practice this concern can often be dealt with by providing the planning authority with a noise break-in analysis. By assessing the amount of noise entering a residential dwelling through the walls, windows, ventilation and roof, we can predict what the internal noise levels will be within an apartment or home when it is finished.

This ‘Noise Break-in Assessment’ as they are often referred to will allow us to demonstrate to the local planning authority on your behalf that development on your site is practical and supportable.

This calculation is normally completed for the properties closest to the sources of noise, however it can be expanded to cover a whole development, helping to ensure that glazing and ventilation is not over specified and helping to reduce build costs. With a 150 home development, that reduction in costs could be quite significant. We can also advise on the latest background acoustic ventilation in use and how it might benefit the development.

All Dragonfly Acoustics noise assessments for planning include a break-in assessment for the most exposed properties as standard; we feel it is an essential part of providing our clients with what they need to achieve their planning permission, even if they may not know they need it!