- Aug 8, 2023

Noise Impact Assessments for Air Source Heat Pumps and Air Conditioning (AC) Units. (BS4142)

Air source heat pumps (ASHPs) and air conditioning units (AC) have risen in popularity as energy-efficient and environmentally friendly alternatives to traditional heating and cooling systems. They harness heat from the surrounding air, providing warmth during colder months and cooling homes during the summer. Despite their benefits, there is a shared concern among local authorities regarding the noise these systems can produce.

The existing permitted development rights have limitations when it comes to altering or modifying the acoustic climate of an area. If noise sources are perceived to be causing a disturbance, local authorities are obligated to investigate, and this may lead to enforcement measures. Unfortunately, the incidence of such action has increased with the growing adoption of ASHPs. The costs associated with retrospective planning and the need to potentially remove, relocate, or mitigate noise issues are often significantly higher compared to pre-emptively conducting a suitable and comprehensive noise impact assessment before installation. We are regularly contacted to help resolve such issues.

A common misconception is that the MCS (Microgeneration Certification Scheme) installer accreditation guarantees adequate noise control. In reality, it is the local authority that establishes noise criteria and investigates for statutory nuisances. Typically, local authorities will request a Noise Impact Assessment by a suitably qualified acoustic consultant and following the methodology outlined in British Standard BS 4142:2014+A1:2019. This standard provides guidelines for evaluating and managing noise emissions from ‘industrial and commercial sources.’

The assessment process involves two key steps. First, sound monitoring equipment is set up at or near the site to measure the representative community noise levels. This step requires appropriate weather conditions and considerations for relevant time periods. Second, ambient noise levels are measured when the noise source is active, under similar conditions. The specific noise source's impact is then calculated against residual levels, accounting for any tonal, impulsive, or intermittent corrections. The resulting rating level indicates whether the new noise source poses a ‘significant’ or a ‘low adverse impact’. Local authorities often have their own acceptable impact criteria to consider, and this can vary considerably across the country. We can discuss this in detail with your local authority if need be.

For units that are not yet installed (and so cannot be measured), BS 4142 permits impact calculations based on reliable sound level data (this may come from the manufacturer or by performing additional measurements elsewhere). If required, a mitigation strategy can be outlined in the report to demonstrate ASHP noise impact levels will meet the local authority requirements. This could involve suggesting an alternative unit, relocating the ASHP to a less noise-sensitive area, or specifying sound reduction measures like noise barriers or acoustic enclosures.

JG Acoustics Ltd can provide visual ISO9613 noise models with SoundPlan software for robust outdoor sound propagation calculations, aiding in presenting these options effectively to local authorities. Additionally, compliance with BS 8233 and WHO community noise guidelines for internal noise levels are often also required and can also be demonstrated in our reports.

JG Acoustics Ltd are based in Kent and can conduct noise impact assessments throughout the UK that are tailored to your specific needs. Get in touch with us today to discuss your requirements further.

info@jgacoustics.co.uk

+447946265086

Noise Impact Assessments for Air Source Heat Pumps and Air Conditioning (AC) Units. (BS4142)

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