What do you do when the world sounds different?

Lewis Stonehouse \ 26th Mar 2020

Empty and quiet city roads during coronavirus outbreak

At Hydrock, we’re doing everything we can to adopt a ‘business as usual’ approach whilst prioritising the health and safety of our colleagues and clients during the outbreak of COVID-19. However, with huge swathes of the population working remotely, how do we conduct noise surveys, and what’s the impact from the data gathered from receptors in recent days? Lewis Stonehouse offers an alternative approach.

It’s quiet out there

Noise surveys form a key part of a planning submission and are a core part of an acoustician’s work. During events that cause disruption to the usual flow of things, notably reduced road travel, it is generally accepted that results from noise surveys may not be valid. We commonly experience this on sites near schools during holiday periods. Usually the approach is to delay surveys until schools go back.

With the Covid-19 situation developing daily and increasingly strict measures in place, it’s obvious to see that current road traffic conditions are far from typical. In addition to this, businesses are operating differently meaning commercial and industrial noise is atypical. Aviation noise is significantly different to usual, and even rail noise is reduced with far fewer trains running. In essence, our world both looks and sounds different.

The challenge presented by the current situation is that being unable to undertake surveys could delay validating planning applications. The usual approach of pushing surveys back until an event has concluded does not apply in this case, as we do not know when things will return to ‘normal’, or indeed whether we will have a new normal.

Establishing the preliminary picture

Keen to support our clients and keep their projects moving forward, Hydrock’s acoustics team have drawn up ideas on alternative approaches to quantify the noise climates around site projects. Some of the options available include:

- Drawing on recent surveys (both by Hydrock and others via publicly available information) undertaken in the vicinity of a site;

- Referencing DEFRA road and rail noise maps;

- Noise modelling based on traffic forecasting and publicly available traffic data;

- Noise modelling based on train schedules;

- Referencing noise contours published by airports;

- Calling on historic data for industrial/commercial uses.

It is important to remember that any combination of the above can be used, both to validate one source of information against another and to develop a reasonably detailed ‘preliminary’ picture of the noise climate around a given site.

Clearly, using any such approach presents a risk to the environmental health departments within local authorities, and they may not accept these alternatives. However, we believe that by taking care to consult and by working closely with local authorities, it is possible to gain their understanding and cooperation during these challenging times.

It’s important to remember, whilst these ideas could be suitable for noise assessments, it will be necessary to complete a noise survey at some point in the project’s lifecycle. We anticipate that local authorities will seek to secure this via a suitably worded planning condition. Ultimately, it is also important to have accurate data when acoustically designing a building, so any new surveys that are required will need to be addressed as soon as possible.

Proactivity and creativity are the watchwords to help our industry in these unique and challenging times.