dBx Acoustics

The Planning (Agent of Change) Bill – What It Means for Acoustics

The Planning (Agent of Change) Bill gets its second reading in Parliament on October 26th. It’s going to be a while before we see it enshrined in law but we are already seeing local authorities being more considerate of the effect that new residential development will have on existing noise sources such as clubs, pubs and industry.

(UPDATE – the second reading will now be on July 6th. There was no time for the bill to be heard on June 15th due to Parliament running out of time while an MP tried to block a bill on upskirting. This was not a good day for democracy!)

The bill is long overdue – and doesn’t introduce anything which shouldn’t be a part of good planning practice anyway. We have long advocated that it should be the responsibility of developers to protect their tenants from existing noise sources as part of their design – but unless the local authorities insist upon this and enshrine it within planning conditions, non-constant noise sources such as from events are often conveniently ignored.

The problem with entertainment noise…

The ‘problem’ with noise from venues often isn’t the overall noise level, it’s the low frequency noise which tends to disturb residents. Mitigating this can be expensive, as low frequency is harder to control than higher frequencies – it can mean thicker glazing units, and thicker partitions. The cost of providing mechanical ventilation systems where noise levels with windows open for natural ventilation are too high is also a huge issue for developers. Understandably, from the Developer’s point of view, they need to comply with planning but they also need to keep control of costs if their development is to remain viable. How can we establish an appropriate balance?

What are the acoustic requirements for new development?

The existing standard which is typically used when considering noise for new residential developments is BS 8233:2014. Unfortunately this sets noise limits as a single figure only, and doesn’t delve into the frequency content of the noise source.

Some local authorities such as Manchester have published comprehensive guidance on planning and noise which considers low frequency noise when a new residential premises is structurally connected to an entertainment venue (or vice versa) but doesn’t set criteria for the frequency content of noise transferred to residents via windows and ventilation. We’re also coming across other authorities now which are trying to implement the principles of Agent of Change but there’s no consensus on what appropriate design standards should be implemented.

The ‘burnt toast’ question!

Even ignoring, for a moment, the low frequency noise issues, there’s another thorny issue rearing its head.

If facades, glazing and ventilation are designed appropriately to control noise intrusion, what about ‘purge ventilation’, i.e. opening the window when you burn the toast? There’s a strong argument that people should have the freedom to open their windows at any time, as long as they have the option of sufficient ventilation and noise insulation with the windows closed. Arguably, if you then choose to open the windows, you are also choosing to expose your self to higher noise levels. But some planning officers are becoming nervous about this, wary that they will then still receive noise complaints about existing venues and find themselves in a very difficult position.

So. We have existing venues who want to stay in business, developers who are cost conscious, planning officers who don’t need extra work, and future residents who probably won’t understand why the noise they can hear when they open their windows isn’t actually a nuisance. What’s the solution?

At dBx Acoustics we think that there are a two key actions;

  • We need clear and consistent design guidance on control of entertainment and low frequency noise as it affects new residential development. This can be provided by acoustic consultants, perhaps led by the Institute of Acoustics,  and there’s a wealth of research and real world experience to draw on. This, in turn, should be incorporated into BS 8233:2014 and the new revision of the NPPF.
  • People will always want to open their windows. Who are we to stop them? But in order to protect venues, we think it’s important to make people aware of how this will affect the noise levels they are exposed to and to make it clear that by purchasing or renting the property they are accepting this. This should be written into sales and tenancy documents but we suggest there should also be a permanent notice affixed in building communal areas to this effect.

What Can Acoustic Consultants Do?

Developers – I’m sorry. The bill probably does mean that you’ll be paying more on ventilation and glazing. But see this as an opportunity to extract more value from your acoustic consultant!

The noise climate around a site near a venue can be complex, and it’ll change further post-development when the building itself provides some natural screening. Where there’s a venue nearby, or for any large development, a simple noise survey isn’t enough. You should expect your consultant to produce a noise model of the site, calibrated against the survey and then with the development added to see the effect.

Every site is different, but in many cases you will find that although the acoustic requirements for glazing and ventilation are indeed increased on the ‘noisy’ facades of the development, there will be opportunities to save money on the ‘quieter’ facades. If you get your consultant involved early enough (RIBA Stage 1 or Stage 2) they can even guide you on building form and internal layout to provide natural screening and reduce the number of noise sensitive rooms exposed to the highest external levels. Of course, it’s important to do this while your architect is still at the concept stage!

The Future

We’re already seeing good venues being closed due to the mere prospect of future development. As responsible developers, designers and planners, we need to be proactive in ensuring that both future residents, and existing venues, can live harmoniously with each other.

At dBx Acoustics, we’ll be watching the progress of the Bill with interest. In the meantime, we’ll continue to advocate for pragmatic acoustic design which balances the needs of all interested parties.

If you’d like us to keep you updated about Agent of Change and how the emerging proposals are likely to affect acoustic design, just click here to leave us your details.