Noise Monitoring is needed to control the noise level coming from factories, roads and construction sites, which is one of the largest causes of complaints to regulators. The Environment Agency (UK), EPA (Ireland) and local authorities have the power to impose noise limits.
Noise Monitoring & Measurement
Measuring noise is not straightforward. A sophisticated noise meter is required along with a high level of competency. The noise measurement is taken over a period of 30 minutes. The measured noise level may need to be corrected for traffic noise monitoring.
Where noise limits are set these are either along the site boundary or at the nearest noise sensitive locations such as houses, schools, churches and playing fields.
Limits are set for daytime (typically 55 dBA), evening (typically 50 dBA) and night-time (typically 45 dBA) with a complete ban on tonal noise at night.
Tonal noise, such as produced by fans and other rotating equipment, can be particularly disturbing for neighbours. Most regulators impose a complete ban on tonal noise at night. During the day tonal noise is allowed but a penalty is added to the noise measurement.
Often sites will receive complaints about noise but in some cases the noise may be from another source. Noise monitoring through a survey will help identify the source of the noise. We have found that in many cases the complainant has wrongly identified the source of the noise.
Noise prediction models
Where noise is causing complaints a noise prediction model will help identify the most cost effective solution. Often sites will attempt to reduce the noise level with trees, bushes or wooden fencing at the boundary. These are usually ineffective. To adequately deal with noise, barriers are best located at the noise source. Noise monitoring through a prediction model will identify the correct placement and height of noise barriers and allow a range of possible solutions to be evaluated quickly and cheaply.
Environmental noise proposed developments
When planning new developments for example for factories, water treatment works or similar infrastructure, it is normal to support the planning application with a noise prediction model. Environmental Efficiency is able to do this work and write the appropriate chapters for Environmental Impact noise Assessments.
A distillery was receiving noise complaints from neighbours regarding noise at night. The distillery had installed barriers and lagged external pipework but with no significant effect on noise. Environmental Efficiency were called in to undertake noise monitoring through a noise prediction model. The model took account of all external plant such as compressors, cooling towers and evaporators plus the existing noise barriers. The effect of new barriers at various locations were explored plus the effect of relocating equipment.
The model identified that by turning a cooling tower around by 180 degrees this would solve the noise problem. The cost of turning the cooling tower was a fraction of what had been spent to date to resolve the problem. Post noise monitoring showed that the proposed solution worked.
What guidance is available?
In Ireland the EPA have published guidelines known as NG4. The previous two documents NG1 and NG2 are withdrawn. In the UK the equivalent document is the IPPC Horizontal Guidance Note for Noise Assessment and Control.
Environmental Efficiency has significant experience in environmental noise monitoring and in resolving these issues for clients. Where appropriate we can provide Expert Witnesses to challenge allegations of noise coming from your site and perform noise assessments.