**Document:** Plant Noise Breakout Assessment **Application:** 13/00726/REM — Reserved Matters Application for conversion and extension of existing stores/maintenance building to create a web hosting centre (phases1&2 only) **Decision:** Permitted **Decision Date:** 2013-07-31 **Parish:** Braddan **Document Type:** report / planning_statement **Source:** https://planningportal.im/a/18288-braddan-greenhill-conversion-extension/documents/1314840 --- # Plant Noise Breakout Assessment Subject: Plant noise breakout assessment Date: 15 August 2013 Job No: Ref AAc\230750-00\TN01 ## 1 Introduction Arup has been requested to undertake an assessment of noise breakout from building services plant associated with the proposed conversion of part of the existing Manx Telecom Data Centre in the Isle of Man. This assessment demonstrates that noise breakout to the nearest noise sensitive receivers complies with the planning criteria, as set out below. ## 2 Planning criteria Approval of the Reserved Matters planning application Ref 13/00726/REM for conversion and extension of the existing Manx Telecom Data Centre has been granted with the following acoustic condition. 1. Noise levels resulting from the proposed development, once operational, at the surrounding school, office and meeting room shall not exceed $35\mathrm{dBL}_{\mathrm{Aeq,1hr}}$ internally and $45\mathrm{dBL}_{\mathrm{Aeq,1hr}}$ externally and at the nearest residential premises shall not exceed $30\mathrm{dBL}_{\mathrm{Aeq,1hr}}$. 2. Prior to commencement of the works on site in accordance with the approved document, further details of the acoustic surrounding must be approved by the Planning Authority and thereafter the surrounds erected in accordance with these details. Figure 1 shows the location of the proposed site with the noise receivers mentioned in the planning condition identified. Figure 1: Data centre site and nearest noise sensitive receivers ![A site plan illustrating the proposed data centre extension and plant enclosure at the Greenhill Communications Centre, showing the site boundary and surrounding properties like a primary school.](https://images.planningportal.im/2013/06/160822.jpg) ## 3 Plant noise assessment [Table omitted in markdown export] ![Site layout plan illustrating the proposed arrangement of a data centre, dry air coolers, emergency generators, transformers, and acoustic screens.](https://images.planningportal.im/2013/06/160823.jpg) Figure 2 below shows the plant associated with the data centre. Sound power noise levels of each noise source are given in Table 1. Figure 2: Data centre plant locations Table 1: Plant item noise levels, dB Two modes of plant operation have been assessed as detailed below; **Normal operation plant** - 2 Pop Room DX Condensers - Office DX Condenser - 1 CRAC unit DX Condenser - 1 Dry Air Cooler - Circulating Pump P1 - Circulating Pump P3 - 1 Transformer **Emergency operation plant** - As normal operation plus - 1 Packaged emergency generator Emergency operation of plant will only occur during instances of total power failure to the site and it is anticipated that this will be a very infrequent occurrence. The emergency generation plant will be tested for 10 minutes each month and this will be scheduled to occur at times of day when the background noise is at its highest thus lessening the effect on nearby noise sensitive receivers. Local screening has been provided to the noisiest piece of plant equipment that being the dry air coolers as shown in Figure 2. A solid screen 3m high having a surface mass of 12kg/m² will be erected in the location shown providing screening to the school and residential receivers. The Planning Condition stipulates criteria for both commercial and residential premises and a worst case assessment of noise from the plant at the closest noise sensitive receivers falling into these categories has been undertaken. The closest receivers have been identified as Ballacottier Primary School and Farmhill Meadows. Noise levels at the Restart Unit will be lower than those at the School due to screening afforded by the existing buildings and it is also further distant than the school. The assessment allows for all plant operating at full duty simultaneously for normal operation. A summary of the assessment results is shown in Table 2. Spreadsheets for each assessment are shown in Figure 3 to 6 at the end of this assessment. [Table omitted in markdown export] Table 2: Calculated worst case plant noise to nearby receivers ### 4 Conclusions An assessment of noise breakout from plant associated with the external plant compound for the converted data centre has been undertaken. The assessment has been undertaken for the worst case scenario where all plant operates at full duty simultaneously. The assessment shows that the existing plant selections together with local screening do not exceed the limiting level at the nearest noise sensitive receivers for normal operation plant. Noise levels during emergency operation of generators have been calculated and presented for consideration but as this occurs very infrequently the anticipated effect to the nearby receivers is deemed to be insignificant. Figure 3: Assessment of breakout noise to Ballacottier Primary School during normal operation of plant ![drawing from page 4](https://images.planningportal.im/2013/06/160824.jpg) ARUP Consultants in Acoustics • Vibration • Venues • AudioVisual [Table omitted in markdown export] Figure 4: Assessment of breakout noise to Ballacottier Primary School during emergency operation of plant [Table omitted in markdown export] Plant noise breakout assessment 15 August 2013 AAc\230750-00\TN01 Figure 5: Assessment of breakout noise to Farmhill Meadows during normal operation of plant [Table omitted in markdown export] Figure 6: Assessment of breakout noise to Farmhill Meadows during emergency operation of plant [Table omitted in markdown export] --- *Data sourced from the Isle of Man public planning register under the [Isle of Man Open Government Licence](https://www.gov.im/about-this-site/open-government-licence/).* *Canonical page: https://planningportal.im/a/18288-braddan-greenhill-conversion-extension/documents/1314840*