Information Response - Email 1 of 2 MCU16/0153 & REC16/0041

3.          Response to Items 14 to 16 – IGA Mechanical Plant Noise
            Emissions
Noise calculations were initially undertaken within a spreadsheet format and incorporated distance
attenuation and Fresnel barrier effect algorithms. The noise modelling of the IGA rooftop plant has been
undertaken within Soundplan (Version 7.4). The source noise level data has been reviewed and a tonality
penalty of +2dB has been applied for a potential tonal component in the 200Hz one-third octave band.
The noise levels have been predicted at the nearby sensitive locations with and without the proposed noise
screen. The calculations undertaken with Soundplan indicate that with a 1.0m high screen above the top of
the A/C plant located around the root-top platform the 37dBA Leq,adj,1hour external noise goal is still
exceeded. However, the internal noise goal 30dBA Leq,adj,1hour can be achieved with the windows closed, the
internal noise level calculations are presented in Attachment B. As the windows can be closed to mitigate
the potential noise intrusion, ventilation requirements may need to be considered.

Table 3.1   Predicted Mechanical Plant Noise Levels
 Day              Level/Floor         Predicted Noise       Predicted Noise Levels with an Acoustic Screen
                                      Levels without        1.0m Higher than the top of the A/C Plant
                                      Acoustic Screen
                                      LAeq,1hour dBA        LAeq,1hour dBA   Tonality        LAeq,adj,1hour dBA
                                                                             Penalty dB
 House 1          Upper               44                    33               2               35
 House 2          Upper               46                    35               2               37
 House 3          Upper               48                    36               2               38
 House 4          Upper               48                    37               2               39
 Linea House 25   Upper               47                    37               2               39
 Linea House 26   Upper               48                    38               2               40
 Unit 06          1st floor           46                    36               2               38
 Unit 07          1st floor           46                    36               2               38
 Unit 08          1st floor           47                    36               2               38
 Unit 09          1st floor           47                    36               2               38
 Unit 10          1st floor           48                    36               2               38
 Unit 14          1st floor           45                    32               2               34
 Unit 15          1st floor           46                    37               2               39
 Unit 16          1st floor           46                    37               2               39
 Unit 22          2nd floor           46                    36               2               38
 Unit 23          2nd floor           46                    37               2               39
 Unit 24          2nd floor           47                    37               2               39
 Unit 25          2nd floor           48                    37               2               39
 Unit 26          2nd floor           49                    37               2               39
 Unit 30          2nd floor           51                    39               2               41
 Unit 31          2nd floor           50                    38               2               40
 Unit 32          2nd floor           50                    38               2               40

The recommended noise barrier is required to have a minimum surface density of 12.5kg/m2 and an
absorptive lining on the plant side of the barrier.
Referring to Item 16 of the Information Request, the existing IGA shopping centre building provides a
significant barrier for emissions from the loading dock area to the nearest proposed houses (Houses 1-4)


8816R02V01.docx                                                                                               7