Services · Plant noise assessments
Planning-ready BS 4142 plant noise assessments for air conditioning, heat pumps, kitchen extract, condensers, chillers and rooftop plant beside homes.
We measure the background sound at the nearest neighbours, predict how your plant will sound at their windows, and set out clear limits and mitigation the council and your installer can work to, following BS 4142:2014+A1:2019.
MIOA acoustic consultant · Class 1 instrumentation · Fixed-fee quotes · Site visits typically within 3–5 working days
At a glance
Standard
BS 4142:2014+A1:2019
Typical survey
24 hours to several days
Deliverable
Plant noise limits and report
Used for
Planning, conditions, complaints
LA90
Background sound level measured at the nearest homes
+10 dB
Rating above background: likely significant adverse impact
+5 dB
Rating above background: likely adverse impact
≤ 0 dB
Rating at or below background: low impact
Initial estimates from BS 4142:2014+A1:2019 section 11. Context always matters, and many councils set their own plant noise limits relative to background.
When you need one
If fixed plant could be heard at a neighbour's window, most councils will want evidence that it won't cause disturbance, either before permission is granted or as a condition.
New or replacement condensers, chillers and rooftop units on shops, offices, restaurants and homes.
Air source heat pumps that fall outside permitted development, or where the council asks for more than an MCS check.
Extract fans for restaurants and takeaways, MVHR terminals and car park ventilation close to homes.
Plant noise conditions to discharge, or Environmental Health enquiries about existing equipment.
Already received a planning condition or an Environmental Health request for a noise assessment?
Send us the detailsWhat's included
BS 4142 compares the sound from your plant, adjusted for any tones, impulses or on/off character, with the background sound neighbours normally hear. The result is weighed against the context of the site.
Selecting the right unit and position at design stage is far cheaper than retrofitting after a condition has been breached.
Heat pump guide
Are Air Source Heat Pumps Noisy? 7 Proven Facts
Read the guide →
Background sound survey
Measurement of the LA90 background sound level over the hours the plant will run, including the quietest night-time periods.
Output: representative background level
Plant noise predictions
Specific sound levels predicted at each neighbour from manufacturers' data, or measured where plant already exists.
Output: specific sound levels
Character corrections
Penalties for tonality, impulsivity and intermittency, so a whine, click or cycling unit is assessed fairly.
Output: rating level
Impact and context
The rating level compared with background, then weighed against context such as existing noise and the type of neighbourhood.
Output: impact assessment
Plant noise limits
Clear limits by day and night at each neighbour, so any unit selected later can be checked against them.
Output: dB limits for procurement
Mitigation design
Screens, enclosures, silencers, quieter selections, re-siting or time controls, with the reduction each one needs to achieve.
Output: mitigation schedule
Related services
Plant noise is often one part of a wider planning picture. These services are regularly combined with a BS 4142 assessment.
Planning-ready noise impact assessments for residential, commercial and mixed-use schemes, including responses to planning conditions.
Noise impact assessments →
Day and night noise surveys that set glazing, ventilation and garden design for new homes near roads, railways and industry.
Environmental noise surveys →
Construction noise and vibration predictions, Section 61 applications and on-site noise monitoring.
Construction noise monitoring →
ProPG and BS 8233 assessments for new homes, conversions and Class MA prior approval, including overheating.
Residential noise consultants →
How it works
A clear, fixed-fee process built around your planning programme. You always know what is being assessed, why, and when your report will be ready.
01
Share the site address, drawings and any planning condition or EHO comments. We confirm the right assessment and send a fixed-fee quote.
02
We measure the existing noise climate with Class 1 instrumentation, including night-time and unattended monitoring where the assessment calls for it.
03
Results are assessed against BS 8233, ProPG, BS 4142 or BS 5228 as relevant, with clear, practical mitigation set out for your design team.
04
We respond to questions from planning officers and Environmental Health, and help you discharge noise-related planning conditions.
What we assess
Each assessment uses the actual selections and operating hours for your scheme, or worst-case assumptions where equipment hasn't been chosen yet.
Split systems, VRF condensers and rooftop units on shops, offices and restaurants.
Air source heat pumps for homes and commercial buildings, including multiple-unit installations.
Restaurant and takeaway extract fans, including late-night operation.
Condensers and chillers for supermarkets, convenience stores and cold rooms.
MVHR terminals, car park fans and plant room louvres.
Workshops, deliveries, yards and other industrial sound within the scope of BS 4142.
Policy and guidance
Reports are framed around national planning policy, the relevant Local Plan and any plant noise criteria your council publishes or sets by condition.
Planning policy
NPPF and PPG Noise
Planning Policy Wales and TAN 11
NPF4 and PAN 1/2011
Local requirements
Council plant noise criteria
Planning conditions
Agent of Change
Environmental Health guidance
Standards and guidance
BS 4142:2014+A1:2019
BS 8233:2014
ISO 9613-2
MCS 020(a)
NR curves
Where we work
We assess plant noise for developers, architects, M&E consultants, installers and business owners throughout the UK.
Across England
Planning noise work for councils from Cornwall to Cumbria, run from our Southampton base.
London · South East · South West · East of England · Midlands · North West · North East · Yorkshire
Wales, Scotland, Northern Ireland and Guernsey
Assessments framed around each nation's own planning policy and Environmental Health expectations.
Cardiff · Newport · Swansea · Glasgow · Edinburgh · Dundee · Aberdeen · Belfast · Guernsey
Frequently asked questions
Straight answers to the questions developers, installers and business owners ask us most about BS 4142 and plant noise.
BS 4142:2014+A1:2019 is the British Standard for rating and assessing industrial and commercial sound, including fixed plant. It compares the rating level of the new sound at a neighbour with the existing background sound level, then considers the context to judge the likely impact.
The background level (LA90) is the sound normally heard when nothing unusual is happening. The specific level is the sound of the plant on its own. The rating level is the specific level plus any corrections for tones, impulses or intermittent operation.
BS 4142 adds up to 6 dB for tonality, up to 9 dB for impulsivity and 3 dB for intermittency, or 3 dB for other distinctive characteristics, depending on how noticeable each feature is at the neighbour.
Simple noise assessments can start from around £750, and a planning noise survey and report for a small-to-medium project commonly costs £1,000–£2,500+. The fee depends on how long monitoring needs to run, the number of measurement positions and what the council requires. We always provide a fixed-fee quote. Our guide to noise assessment costs explains the main price factors.
Often not, if the installation qualifies as permitted development, which includes meeting the MCS 020(a) noise standard at the nearest neighbour. If it doesn't qualify, for example because of the unit's position, the property's listed status or local restrictions, planning permission may be needed and the council may ask for a noise assessment to BS 4142. Our guide to reducing air source heat pump noise covers the practical options.
Usually, yes. The background sound level has to be measured at or representative of the nearest homes, ideally over the hours the plant will run. Predictions then use the manufacturer’s noise data for the units you plan to install.
Many councils require plant to be a set number of decibels below background, sometimes 5 or 10 dB. We assess against the council’s own criterion as well as BS 4142, as on our Belsize Road case study in Camden.
Yes. We can measure the plant as it operates, identify any tonal or low-frequency content, and recommend practical changes, from maintenance and time controls to screening or replacement.
A planning noise report sets out the site and proposal, the relevant policy and standards, the survey methodology and equipment, the measured results, the assessment against the applicable criteria and any mitigation needed, such as glazing, ventilation, barriers or plant attenuation. See what a noise impact assessment report includes for a full breakdown.
Plant noise assessments
Send us the site address, drawings and any comments from the council or Environmental Health. We'll confirm exactly which assessment you need and send a fixed-fee quote, aiming to reply within 24–48 hours.
MIOA acoustic consultant · Class 1 instrumentation · Fixed fees · UK-wide
