Appendix 4.3 - Operation Noise Impact Assessment | |||||||||||||
Cumulative Noise Impacts from Pui O RWPS and Pui O No. 2 RWPS - Mitigated | |||||||||||||
3 Main Pumps with 1 Main Pump standby in Pui O RWPS and 4 Mains Pumps in Pui O No. 2 RWPS | |||||||||||||
NSR "LWT2" | |||||||||||||
Potential Noise Sources | Sound Power Level for Each Equipment |
No. | Total Sound Power Level |
Distance to Sources |
Distance Corrections | Façade Effect |
Screening Effect/ Slight Line Effect |
Acoustic Panel/ Enclosure/ Silencer |
Screening Effect/ Slight Line Effect/ Acoustic Louvers/ Enclosure | Predicted Noise Level |
SPL,dB(A) | ||
Pui O RWPS | 1 | Four Main Pumps (3 duty + 1
standby) @ 950kW at the "Inlet Work" (Basement) * |
96 | 3 | 100.8 | 97 | -47.7 | 3 | -10 | -10 | -20 | 36.1 | |
2 | Blower inside Blower Room | 104 | 1 | 104.0 | 102 | -48.2 | 3 | -30 | -30 | 28.8 | |||
3 | Ventilation Fans - North (with Acoustic Louvers) | 79 | 6 | 86.8 | 108 | -48.6 | 3 | -10 | -10 | -20 | 21.2 | ||
Ventilation Fans - North (with Acoustic Louvers) | 79 | 2 | 82.0 | 107 | -48.5 | 3 | -10 | -10 | -20 | 16.5 | 37.0 | ||
Pui O No. 2 RWPS | 1 | Four Main Pumps (4 duty) @ 950kW at the "Inlet Work" (Basement) * |
96 | 4 | 102.0 | 114 | -49.1 | 3 | -10 | -10 | -20 | 35.9 | |
2 | Blower inside Blower Room | 104 | 1 | 104.0 | 118 | -49.4 | 3 | -30 | -30 | 27.6 | |||
3 | Transformers (Enclosed) | 85 | 2 | 88.0 | 122 | -49.7 | 3 | -10 | -10 | 31.3 | |||
4 | Ventilation Fans - West | 79 | 4 | 85.0 | 110 | -48.8 | 3 | 39.2 | |||||
Ventilation Fans - North (with Acoustic Louvers) | 79 | 2 | 82.0 | 136 | -50.7 | 3 | -10 | -10 | -20 | 14.3 | |||
5 | Roof Extractor | 79 | 4 | 85.0 | 112 | -48.9 | 3 | 39.1 | 43.5 | ||||
Total SPL = | 44.4 | ||||||||||||
NSR "LWT3" | |||||||||||||
Potential Noise Sources | Sound Power Level for Each Equipment |
No. | Total Sound Power Level |
Distance to Sources |
Distance Corrections | Façade Effect |
Screening Effect/ Slight Line Effect |
Acoustic Panel/ Enclosure/ Silencer |
Screening Effect/ Slight Line Effect/ Acoustic Louvers/ Enclosure | Predicted Noise Level |
SPL,dB(A) | ||
Pui O RWPS | 1 | Four Main Pumps (3 duty + 1
standby) @ 950kW at the "Inlet Work" (Basement) * |
96 | 3 | 100.8 | 59 | -43.4 | 3 | -10 | -10 | -20 | 40.4 | |
2 | Blower inside Blower Room | 104 | 1 | 104.0 | 47 | -41.3 | 3 | -30 | -30 | 35.7 | |||
3 | Ventilation Fans - North (with Acoustic Louvers) | 79 | 6 | 86.8 | 59 | -43.4 | 3 | -10 | -10 | -20 | 26.4 | ||
Ventilation Fans - North (with Acoustic Louvers) | 79 | 2 | 82.0 | 75 | -45.4 | 3 | -10 | -10 | -20 | 19.6 | 41.8 | ||
Pui O No. 2 RWPS | 1 | Four Main Pumps (4 duty) @ 950kW at the "Inlet Work" (Basement) * |
96 | 4 | 102.0 | 133 | -50.5 | 3 | -10 | -10 | -20 | 34.5 | |
2 | Blower inside Blower Room | 104 | 1 | 104.0 | 128 | -50.1 | 3 | -30 | -30 | 26.9 | |||
3 | Transformers (Enclosed) | 85 | 2 | 88.0 | 130 | -50.3 | 3 | -10 | -10 | 30.7 | |||
4 | Ventilation Fans - West | 79 | 4 | 85.0 | 123 | -49.8 | 3 | 38.3 | |||||
Ventilation Fans - North (with Acoustic Louvers) | 79 | 2 | 82.0 | 140 | -50.9 | 3 | -10 | -10 | -20 | 14.1 | |||
5 | Roof Extractor | 79 | 4 | 85.0 | 131 | -50.3 | 3 | 37.7 | 42.3 | ||||
Total SPL = | 45.1 | ||||||||||||
NSR "ALWT1" | |||||||||||||
Potential Noise Sources | Sound Power Level for Each Equipment |
No. | Total Sound Power Level |
Distance to Sources |
Distance Corrections | Façade Effect |
Screening Effect/ Slight Line Effect |
Acoustic Panel/ Enclosure/ Silencer |
Screening Effect/ Slight Line Effect/ Acoustic Louvers/ Enclosure | Predicted Noise Level |
SPL,dB(A) | ||
Pui O RWPS | 1 | Four Main Pumps (3 duty + 1
standby) @ 950kW at the "Inlet Work" (Basement) * |
96 | 3 | 100.8 | 108 | -48.6 | 3 | -10 | -10 | -20 | 35.1 | |
2 | Blower inside Blower Room | 104 | 1 | 104.0 | 109 | -48.7 | 3 | -30 | -30 | 28.3 | |||
3 | Ventilation Fans - North (with Acoustic Louvers) | 79 | 6 | 86.8 | 99 | -47.9 | 3 | -10 | -20 | 21.9 | |||
Ventilation Fans - North (with Acoustic Louvers) | 79 | 2 | 82.0 | 95 | -47.6 | 3 | -10 | -20 | 17.5 | 36.2 | |||
Pui O No. 2 RWPS | 1 | Four Main Pumps (4 duty) @ 950kW at the "Inlet Work" (Basement) * |
96 | 4 | 102.0 | 125 | -49.9 | 3 | -10 | -10 | -20 | 35.1 | |
2 | Blower inside Blower Room | 104 | 1 | 104.0 | 112 | -49.0 | 3 | -30 | -30 | 28.0 | |||
3 | Transformers (Enclosed) | 85 | 2 | 88.0 | 109 | -48.7 | 3 | -10 | -10 | 32.3 | |||
4 | Ventilation Fans - West | 79 | 4 | 85.0 | 117 | -49.4 | 3 | 38.7 | |||||
Ventilation Fans - North (with Acoustic Louvers) | 79 | 2 | 82.0 | 101 | -48.1 | 3 | -10 | -20 | 16.9 | ||||
5 | Roof Extractor | 79 | 4 | 85.0 | 125 | -49.9 | 3 | 38.1 | 42.9 | ||||
Total SPL = | 43.7 | ||||||||||||
NSR "ALWT2" | |||||||||||||
Potential Noise Sources | Sound Power Level for Each Equipment |
No. | Total Sound Power Level |
Distance to Sources |
Distance Corrections | Façade Effect |
Screening Effect/ Slight Line Effect |
Acoustic Panel/ Enclosure/ Silencer |
Screening Effect/ Slight Line Effect/ Acoustic Louvers/ Enclosure | Predicted Noise Level |
SPL,dB(A) | ||
Pui O RWPS | 1 | Four Main Pumps (3 duty + 1
standby) @ 950kW at the "Inlet Work" (Basement) * |
96 | 3 | 100.8 | 147 | -51.3 | 3 | -10 | -10 | -20 | 32.4 | |
2 | Blower inside Blower Room | 104 | 1 | 104.0 | 153 | -51.7 | 3 | -30 | -30 | 25.3 | |||
3 | Ventilation Fans - North (with Acoustic Louvers) | 79 | 6 | 86.8 | 141 | -51.0 | 3 | -10 | -20 | 18.8 | |||
Ventilation Fans - North (with Acoustic Louvers) | 79 | 2 | 82.0 | 132 | -50.4 | 3 | -10 | -20 | 14.6 | 33.4 | |||
Pui O No. 2 RWPS | 1 | Four Main Pumps (4 duty) @ 950kW at the "Inlet Work" (Basement) * |
96 | 4 | 102.0 | 139 | -50.8 | 3 | -10 | -10 | -20 | 34.2 | |
2 | Blower inside Blower Room | 104 | 1 | 104.0 | 128 | -50.1 | 3 | -30 | -30 | 26.9 | |||
3 | Transformers (Enclosed) | 85 | 2 | 88.0 | 124 | -49.8 | 3 | -10 | -10 | 31.2 | |||
4 | Ventilation Fans - West | 79 | 4 | 85.0 | 135 | -50.6 | 3 | 37.4 | |||||
Ventilation Fans - North (with Acoustic Louvers) | 79 | 2 | 82.0 | 111 | -48.9 | 3 | -10 | -20 | 16.1 | ||||
5 | Roof Extractor | 79 | 4 | 85.0 | 139 | -50.9 | 3 | 37.2 | 41.8 | ||||
Total SPL = | 42.4 | ||||||||||||
Remark: | |||||||||||||
SPL for Main Pump at 1m = 88 dB(A), provided by WSD | |||||||||||||
SWL for Blowers inside blower room = 104 dB(A), refer to "Outlying Islands Sewerage Stage Phase 1 - Ngong Ping Sewage Treatment Works and Sewerage Investigation" | |||||||||||||
SWL for Transformer = 85 dB(A), refer to "San Wai STW and Ha Tsuen PS -EIA" | |||||||||||||
* Acoustic Louvres provided for ventilation openings of pump hall |