Key points

Listen to this article

Process Engineering is a highly regulated industry with a combination of large plant items and significant process areas that can give rise to problematic noise and vibration levels. Specialist acoustics support is essential when planning a new facility, upgrading plant or complying with new regulations.

Noise can affect Process Industries in several ways, from Noise at Work affecting the health and well-being of employees, through privacy and confidentiality in offices and meeting rooms, to environmental noise emissions causing regulatory problems with Local Planning Authorities or the Environment Agency (EA). In the worst case you may find yourself on the receiving end of a public nuisance or Health and Safety Executive (HSE) investigation.

In this article, Rob Adnitt of Adnitt Acoustics and Paul Shields of AECOM – both members of the Board of the Association of Noise Consultants (ANC) – briefly outline the main points around these issues and show how advice from a recognised acoustics or noise consultant can help to avoid, reduce or resolve problems.

Noise Emissions to Neighbours

You will need to consider noise emissions to your neighbours for new or extended premises or processes, however, you may also be faced with a new housing development near a long-standing existing process or noise complaints from other neighbours.

The first thing to be aware of is that there are no fixed noise limits in law and in each case is considered on its merits. The noise limits you have to work to might be established by a planning condition or a license/permit condition from the EA (or national equivalent); and, in the event of a nuisance complaint there may be no established condition. You should also know that even if you are complying with your planning conditions, this doesn’t stop a nuisance complaint, investigation and enforcement.

Environmental Permit conditions may require periodic noise assessments of facilities to check that noise emissions have not crept up over time or to seek continuing improvement in environmental noise levels.

Assessment Method

The British Standard for assessing industrial and commercial sound affecting people inside or outside dwellings or similar is BS4142 which was most recently revised in 2014 with updates in 2019.

Noise sources in the assessment include:

industrial and manufacturing processes
fixed installations
the loading and unloading of goods; and
mobile plant and vehicles that is an intrinsic part of the overall sound emanating from premises or processes

Noise from the commercial activity is predicted or measured at the neighbour’s location and corrections are added for the acoustic features of the noise (tones, impulses, intermittency) to give a Rating Sound Level. This Rating Level is compared to the Background Sound Level at the location and an initial assessment is made based on whether and by how much the Rating Level is above the Background Level.

Most importantly, the assessment then takes account of uncertainty and the context in which the sound is made, and this may consider factors such as how regular the noise is, the characteristics of the local area, the length of time the noise source has been in existence.

Application of the BS4142 assessment method should be undertaken by a specialist with appropriate qualifications and experience and the standard is written for such an individual rather than the lay person.

The ANC represents acoustics consultancy companies and has recently produced a Technical Note for its members, with the aim of improving consistency of assessment using BS4142.

The ANC website www.theanc.co.uk has a member search facility that can be used to find acoustics consultants across the country who are experts in noise assessments.

There may be discrepancies between specific guidance for particular industrial areas, such as oil and gas, and the British Standard, 4142. A suitably qualified ANC member company should be able to help you reconcile the requirements.

Treatment

If the assessment identifies that noise from the process must be reduced, then a detailed study should be made of the available options.

There may be many sources of noise associated with any given process and the means of noise transfer or which ones are causing the complaint may not be immediately obvious.

A good acoustics consultant will analyse the sources of noise that may affect nearby residents and rank these in order of importance for treatment. Reducing noise at source is always the best approach if feasible. It may be that modifications to existing equipment or replacements are more cost effective and efficient in the long run than acoustic enclosures or barriers.

Case Study 1

A study was made at a Closures and Plastics facility to satisfy a permit condition for noise improvement. Night and day background noise measurements were made at local residential properties and a noise study made of equipment at the factory.

Several sources of noise were found including outside pumps and a pneumatic tube that transported plastic pellets to the main building, producing a high frequency ‘whooshing’ noise audible at the residences. The pumps were treated with a local enclosure and noise from the transport tubes was reduced with a wrap that improved damping and reduced noise emissions.

Case Study 2

An ANC company was employed by a food manufacturing site containing a large number of noise producing activities. A programme of noise measurements, modelling and prediction work was undertaken to provide advice regarding possible noise reduction measures, including alternative “what if” scenarios and a series of noise maps were provided to inform the options.

This noise model was used to model the effect of other proposed changes at the site for a planning application and BREEAM assessments, including:

New air handling unit
Building services plant on new amenity building
The operation of a large new plant item on the site

A trial run of noise monitoring was undertaken based on the noise modelling results. A noise monitor was installed for a month with a series of sound recordings also made to help identify the cause of high noise levels.

Noise at Work

In the UK, the Control of Noise at Work Regulations (2005) and the Control of Vibration at Work Regulations (2005) require the assessment and management of personal exposure. There is an increasing Health and Safety Executive (HSE) focus on measures controlling noise and vibration at source to avoid reliance on hearing protection.

Noise limits are applied to reduce the risk of hearing damage. In some cases, these limits may take the form of simple spot noise limits according to equipment type and area (including accommodation and office areas). Detailed exposure assessments that also consider work patterns may apply with an obligation to reduce exposure to the lowest practicable level.

Vibration surveys cover hand-arm vibration from tools as well as whole-body vibration from work platforms or vehicles.

Software tools can be used to simulate the effects of control across a workforce to determine the benefits.

It is essential to apply the appropriate standard, considering abnormal operating conditions, and assessments should follow HSE guidelines. ANC member companies will operate to the latest standards, identify obvious controllable source or transmission paths, and work with you to find control measures that maximise benefit at optimum cost.

The consultant can provide noise management support including noise and vibration assessments, audits, modelling, and training including:

initial surveys to identify noise issues and levels
analysis of typical work patterns
developing a bespoke noise exposure management tool for each site

Information from the exposure management tool can be used to target noise control and/or organisational measures to reduce noise and vibration exposure to be As Low As Reasonably Possible (ALARP).

Consultants can lead workshops and provided on-site training to staff; additional education and training can be provided to site staff who have a designated responsibility to keep the site noise and vibration assessments up to date.

Case Study 3

A study was made at a Component Coating facility to assess the noise exposure of staff to comply with the current regulations. Several noisy processes were undertaken at the plant including:

Blasting inside Blast Cabinets
Blasting using smaller blasting boxes located within the blasting area – only hands are placed inside the boxes via fixed gloves
Super Polishing

A combination of observations and discussions with staff were used to determine how long each technician would be using a specific machine or be in a specific area during the working day and noise measurements were made at a position equivalent to the technician’s ear position for each process.

Recommended noise control measures included an improvement to sound insulation to the smaller blasting boxes to reduce noise to nearby workers, time management to reduce noise exposure to individual workers and ear defenders only where necessary.

Summary

In a highly regulated industry, specialist acoustics support is essential when planning a new facility, upgrading plant or complying with new regulations.

The ANC represents acoustics consultancy companies and member companies have passed an entry process with an emphasis on quality assurance and technical competence. The ANC produces guidance and provides continuing professional development for its members who are based throughout the UK and Ireland.

The ANC website www.theanc.co.uk has a member search facility that can be used to find acoustics consultants across the country to assist with noise assessments for planning or permit applications; Noise at Work; or assistance defending nuisance complaints or investigation.

Phil Black - PII Editor 28/04/2021

288 6 minutes read

Noise in the Process Industries – What Do You Need To Know?

By Rob Adnitt of Adnitt Acoustics and Paul Shields of AECOM

Noise Emissions to Neighbours

Assessment Method