We’ve recently dealt with the acoustic impacts of development on a variety of different applications in Bristol, including air source heat pumps on a residential site, kitchen extracts for takeaways and noise from music and events spaces. It’s reminded us of how frequently we’re now confronting the issue of noise with development, and how fundamental it can be to securing planning consent. You might have dismissed it as an environmental health responsibility, or a regulatory matter that simply requires compliance with a planning condition. But it’s much more than that.  If you can’t demonstrate that you can adequately manage noise within your development from the outset, your proposals might just be unacceptable in principle. 

So, should you be embarking on a potentially rowdy scheme (or even one with a slight murmur), here’s a few pointers that you might find useful (we fact-checked with ION Acoustics in Bristol, check them out for ‘sound’ advice, www.ionacoustics.co.uk):

  • What Development Matters? – it’s not just your obvious heavy industrial factories which can be loud – almost any form of development can generate noise which is unacceptable to others. We’ve come across cricket training facilities and axe throwing clubs that have demanded acoustic attenuation before LPA’s have been prepared to lend them their support. In urban areas in particular, the drive for mixed-uses can leave us with micro-breweries sitting alongside family apartments, events venues crammed cheek by jowl with office space – all potentially appropriate uses, but requiring some careful reconciliation. The key point here is don’t underestimate the potential impact of your development – if your proposals unreasonably affect your neighbours health and wellbeing, you will need to address it otherwise you’re looking at a refusal. And almost any new outdoor mechanical plant, even an air source heat pump, will likely need a noise assessment for planning. 

Also don’t overlook existing noise sources – if you’re intending to build flats up against a long-standing city centre music venue, a pub garden or even a vehicle repair workshop, it is incumbent on you (as the ‘agent of change’) to provide measures to protect your new tenants, not on the establishment to retrofit soundproofing. 

  • The Planning Remit – Under the planning system, noise is a consideration in the determination of full applications (assessed against pollution and amenity policies in the development plan and the NPPF). It is also a matter for prior approval for certain changes of use, or could justify a whole chapter of an Environmental Statement for an EIA development.

    Whether your project is large or small, development-related noise will be assessed under the TCPA and EIA regulatory framework. The NPPG (updated 2019) provides advice on how planning can manage potential noise impacts in new development. It confirms that planning decisions need to take account of the acoustic environment and consider: 
  • whether or not a significant adverse effect is likely to occur;
  • whether or not an adverse effect is occurring or likely to occur; and, 
  • whether or not a good standard of amenity can be achieved

This approach involves identifying whether the overall effect of any noise created (which can include construction noise) would be above or below the significant observed adverse effect level, as well as  establishing the lowest observed adverse effect level. The relevance of these being that the significant level is the level above which significant adverse effects on health and quality of life occur, and the lowest is that at which adverse effects can be detected (the aims being to avoid significant adverse effects, to mitigate and minimise adverse effects, and to contribute to the improvement of health and quality of life, where possible). 

  • Effects – Adverse or  not? – Adverse effects can result from a combination of factors and can impact on people differently – it really depends on how various factors come together in any particular situation. So the source, level, timing (day or night), frequency, pattern, spectral content (whether the noise contains particular high or low frequency content) and the general character of the noise (whether it contains particular tonal characteristics or other features) will all come into play, as will the local arrangement of buildings and green infrastructure (whether it reflects or absorbs sound). Other factors to consider include whether the noise is cumulative from more than one source, whether any adverse internal effects can be completely removed (by closing windows or installing fixed windows in new developments), whether a small noise increase in an existing noise sensitive location could result in a significant adverse effect, the effects of noise on wildlife and ecosystems (although this is relatively rare and would likely be dealt with by a specialist ecologist), the acoustic environments of new external amenity spaces, and the multiple impacts from commercial developments such as restaurants and bars (so not just noise from the venue, but from customers in the vicinity). All will have a bearing on the effects of noise from your development – and the extent of their adversity. 
  • How to Assess? – Development Plans may include specific standards against which the effects of different forms of development might be assessed in their area. However, these should not be applied as rigid thresholds, as specific circumstances will inevitably vary and the ‘context’ of the sound is an important factor. It’s more pragmatic for the limits of each effect level to be defined for each situation and location. On this basis, LPA’s tend to defer to various British Standards and other recognised methods of rating for guidance rather than Development Plan policies. BS 8233:2014 together with the WHO ‘Guideline for Community Noise’ is commonly used in the assessment of noise affecting dwellings, whilst BS 4142:2014 contains the method for assessing industrial and commercial sound (used for considering plant noise affecting housing). 
  • Mitigation, what can you offer? – Depending on how your effects measure up against the various standards, you may need to put some mitigation in place. This will depend on the type of development being considered, the type of noise involved, and the nature of the proposed location. In general, there are 4 broad types of mitigation:
  • Engineering: reducing the noise generated at source and/or containing it, which could include incorporating insulation, installing a suspended ceiling or floating floor, the use of monitoring devices or sound limiters (within bars and event spaces), noise silencers and bafflers (for extraction vents and flues), and various types of screening (sound insulation casing or acoustically rated louvred screens for plant enclosures, enclosing noisy activities such as waste recycling within a building to reduce emissions)
  • Layout: optimising the distance between the source and noise-sensitive receptors and/or incorporating good design to minimise transmission (such as in housing estates where the use of access roads and garages can be oriented to protect more sensitive rooms, or the use of a barrier block (for example at Byker Grove, where a continuous line with relatively good sound insulation protects the wider estate)
  • Using planning conditions/obligations: restricting the times of activities and specifying permissible noise levels at  different times of the day, use of noise management plans with hospitality venues 
  • Remote mitigation: mitigating the impact on areas likely to be affected by the noise, such as insulation where the impact is on a building, for example in the design of windows and ventilation of the housing affected by the noise

So your mitigation might take various forms, and some schemes might demand more than one form of mitigation (e.g. you might need to control the music levels from an events venue, but also the hum of the ventilation/extraction equipment from the kitchen). The impacts on residential developments may also be partially off-set if residents have access to a relatively quiet external facade within their dwelling or relatively quiet external amenity spaces. So there is potentially some flexibility of mitigation to  be explored.  

  • When to act? – if you are aware that your development proposals are likely to involve acoustic impacts, it’s prudent to identify these and pursue good acoustic design from the outset. For major developments a noise impact/acoustic assessment might be a standard validation requirement, and for EIA developments this would be picked up by the scoping process, but with smaller projects it might not be so obvious. We are finding it more important than ever to get an acoustic consultant on board as early as possible. If they have the ear of the local EHO officer, get the scope and methodology of any assessment agreed up-front, including identifying the nearest receptors and confirming the relevant noise criteria which your development should satisfy.

Your acoustic assessment might be desk-based (considering the spec of some plant against typical background levels for instance), or will more likely involve a baseline survey of existing noise levels, with the effects of your proposals modelled against these. Depending on the situation, the survey might cover both external and internal noise, measured at different receptors, in different climatic conditions and at different times of the day or night. The assessment might be desk-based (using the spec of proposed ventilation kit for instance) or could involve the actual modelling of a noise source (such as amplified music), taking account of any existing building fabric and mitigating factors. Sometimes you may have to measure examples of your noise elsewhere to use as source data for the assessment. 

In short, it will save you time and costs in the long run, and make for a more informed planning application, if you present your assessment work and include details of any mitigation up-front. An early assessment may even lead to significant design revisions before you submit an application.

  • Conditions – finally, depending on what information you’ve included with your submission and depending on the adversity of the impacts, expect any planning consent to feature conditions requiring an acoustic assessment, approval of any consequent mitigation, compliance with a fixed noise limit, or tolerance above any established baseline levels. Be mindful that you are liable to enforcement action if you persistently breach any specified limits. Hours of operation of any hospitality venue will also likely be conditioned, and these will be covered in parallel in any premises licence (some clients prefer to obtain their License before their Planning (or vv) but you could run applications in tandem as it’s often the same Local Authority officers commenting).

So, alot to think about and a very technical area, but one that’s potentially underestimated within some developments (particularly smaller projects) and really shouldn’t be. We can’t strive for well-functioning, mixed-use urban (and rural) areas without properly considering the effects of noise – whether they be adverse or not and whoever they impact upon. There may well be some negotiation to be had and mitigation to be offered, but always a balance to be sought. Check out the NPPF and NPPG as your first points of reference, https://www.gov.uk/guidance/noise–2, then get your acoustic consultant on board ASAP!