Noise at Work Assessment 

SUMMARY

Impact Acoustics Ltd have been instructed by to undertake a background noise survey at the proposed premises to understand the level of impact in relation to the new external Air Source Heat Pump and calculate the resultant noise level at the nearest affected windows at the residential premises adjacent to the development and carry out assessments to BS4142: 2019 as well as working NR criterion set out by the LPA. 

The measurements have been undertaken in accordance with British Standard 4142:2019 and ISO 1996 – Part 2: 2017 to establish if the site has a demonstrable adverse effect in terms of noise that outweigh the benefits of the development. This report aims to establish the following:

- Existing background noise levels at the residential façade (LA90); 

- Noise levels from the Plant (LAeq); 

- Impact on the nearest noise sensitive property. 

Continuous background noise measurements were undertaken at Assessment Position 1. The representative Night time background noise levels (2300 - 0700) was found to be LA90,15min 34 dB This been evaluated from the recorded data. 

Working noise criterion factoring the main assessment methodologies has been set out below in accordance with the National Planning Policy Framework. Criterion has been set on the contextualization of the environment where the plant is installed. From assessment and attendance at site; the site is considered urban and whilst there is a busy road that has a constant steady state flow of traffic; that result dominant residual noise climate during this period (Average Night Time LAeq,8 hour circa 40dB(A)). It is therefore considered the below criterion applicable in order to safeguard the nearby residential amenity from noise emissions associated with the development and in accordance with local planning policy (+/- at representative measured LA90 in accordance with BS4142:2019):

The proposed air source heat pump source levels were 60dB LwA

Hours of operation are 24/7 therefore night time noise assessment has been undertaken.

Noise modelling and calculations were undertaken to assess the impact of the proposed plant using Sound PLAN noise modelling software. The resulting noise emissions form the proposed air source heat pump was 27dB(A) as specific source.

Due to the air source heat pump containing some tonal elements as well as an intermittent noise emissions a +5dB penalty was applied to the specific source level resulting in a working noise rating level of 32dB LAeq,15min in accordance with BS4142:2019.

As the background noise level as measured was 34dB LA90,15min then this resulted i a conclusion of -2dB below background and low impact in accordance with noise policy and BS4142:2019

Conclusions

The operation of the plant has been assessed to establish if the development will have a demonstrable adverse effect in terms of noise that outweigh the benefits of the development. Measurements have been undertaken in accordance with British Standard 4142:2019 and ISO 1996 – Part 2: 2017. This report has established the existing background noise levels at the closest residential facade to the plant locations and the assessment of the impact of the site operation on nearby residential properties. The resulting emissions from the plant running show ‘Low impact’ criteria during operational hours.