Environmental Noise Assessment Services

General environmental noise measurements to BS4142, BS5228 (or the old PPG24) etc are technically simple and straightforward. Longer term 24 hour monitoring is also a simple process – once the system(s) have been installed and set-up. The technical challenges start when you need to go beyond run-of-the-mill measurements into areas such as tonal analysis, mitigation to meet specific criteria or complaint investigation. The following are examples of some of our technical specialities in this field.

planning applications – planning appeals – planning conditions – BS4142 and BS5228 noise assessments, proposed residential developments near roads, railways, industry, airports – proposed new road and railway schemes – industrial premises – airports – new or extended quarries – landfill sites – extended industrial sites and facilities – construction noise and vibration reduction – demolition noise and vibration assessment and control – Section 61 templates and applications – entertainment, venue and event monitoring…

Whilst BS4142 was designed to assess noise from industrial premises, because it is “there” and is quite easy to follow, it is also very widely used (and misused) for a wide range of other applications. The principle is simple: measure the background noise (LA90); measure the noise from the source (LAeq) with corrections for time periods and for the background noise contribution; calculate the difference and add a 5dB correction if there is “character” in the sound to give you a rating. This is then compared with a very vague general table to suggest whether complaints are likely. The two main areas where it is a poor approach are where there is significant low frequency sound (particularly tonal) and in the subjective evaluation of “character”.

A consultant and an EHO stand listening in a field behind a company site: consultant “There is no tone, so no correction”. EHO: “There is a tone, so I want you to reduce your site noise by a factor of x3 (5dB)”. If the EHO assessment prevails, the cost to the company could be very high. If the consultant prevails, no cost at all. The company could be asked to spend a small fortune based on a subjective impression. We find it incredible that so few organisations carry out an objective evaluation of tonal content. No only does it remove the subjective interpretation, it also provides pin-point diagnostic data as the basis for a low cost solution.

For these reasons, in addition to the standard BS4142 measurements, we also provide an objective tonal analysis. This means that, if there is a potential problem, we are already half way along the process to define what would constitute Best Practicable Means mitigation.

The noise from this paper mill had been evaluated by the Local Authority (standard BS4142 assessment) as there were plans for changes to the site and there had also been previous complaints. Our assessment, however, included detailed narrow band tonal analyses that showed that it would not be sufficient to simply reduce the overall noise level. We identified the sources of a number of sets of tones (4 different sets of fans, vacuum pumps, gearbox drone) that were then prioritised for noise control at source – the low frequency drone from the fans being the dominant problem.

Low frequency (LF) noise is often considered to be one of the more challenging environmental noise problems. It can also be the cause of much angst and can become a truly remarkable time-waster…. We have developed a simple three stage procedure and set of diagnostic tools that have proven to be very effective to identify: first – whether there is an objective noise problem: second – if there is, what is the source: third: – what is the best solution?

This procedure typically reduces the time required to identify and resolve low frequency noise problems from weeks, months or years down to a few days. We have also developed some novel solutions, including “Psychological Psylencing” (or acoustic camouflage).

We not only provide a complete range of conventional noise services covering all aspects of environmental noise (and vibration) for the construction and demolition industries, but also a range of additional innovative management and control techniques based on our unique engineering expertise. These are not only re-defining what constitutes best practice under the regulations and standards, but are also dramatically reducing project costs and delays. Our reputation is based on the results we have achieved from introducing new procedures and techniques into a largely traditional industry.

Section 61 Templates and Noise Management Systems
We have developed both template noise prediction programmes and the associated documentation for a wide range of applications. These simplify the process and often allow a substantial proportion of noise projects to be moved in-house to reduce costs. The equivalent of “plug-and-play” for environmental noise. In addition, we have also developed project noise management software that allows you to control noise from multiple sources and processes in “real-time” to keep within tight noise specifications.
We also have a range of industry specific noise training workshops that companies can use to upgrade their in-house knowledge and expertise.

We have extensive experience of event, music  and venue noise measurements – anything from under-the-arches venues up to the NEC and outdoor music festivals, from orchestras and opera to BBC outside broadcasts. In many cases, the projects have also included prediction and mitigation, training in-house staff (up to full IOSH competency for the larger venues) and policing recalcitrant sound engineers…

In addition, we have also developed our own real-time feedback noise monitoring system to aid with the control of environmental noise levels from music events. This provides the sound engineer with a live feed of the noise levels at the key off-site monitoring point to facilitate managing the noise at the mixing desk.

In addition to conventional environmental noise monitoring systems with solar powered logging meters and modem access for remote downloads, we also have access to specialist instrumentation for particular types of application – often developed by ourselves for particular projects. These include noise nuisance recorders (we designed the first bespoke recorder) – sealed, high quality recording devices that are operated by the complainant. These are very useful where noise problems are intermittent – instead of repeatedly turning up on site (often at night) only to have “just missed” the noise, the complainant makes the calibrated recordings for you for post analysis. We have also developed a system that allows remote triggering of acoustic recordings by mobile phone or over the internet e.g. when you need to acquire off-site noise data from intermittent events on your site.