Appendix 4.2  Construction Noise Impact Assessment
(D1)  Calculation of Construction Noise Levels at Representative Noise Sensitive Receivers - Mitigated (Quite Plant)
NSR: "LUT"    
    SWL Distance B.C.* CNL       Cumulative Activities      
Activity   (dB(A)) (m) (dB(A)) (dB(A)) (I) (II) (III) (I)+(II) (I)+(III)A (I)+(III)B (I) + (III)C
(I) Water Mains Construction      
A Excavation of Trench / Breaking up Pavement 108 14 80 80 - - - - - -
B Installation of Pipes and Bedding 103 14 75 75 - - - - - -
C Backfilling 108 14 80 80 - - - - - -
D Reinstating Road Surface 105 14 77 77 - - - - - -
(II) Demolishment of Pui O Raw Water Pumping Station      
A General Site Clearance / Demolition Works 114 - - - - - - - - -
(III) Construction of Pui O Raw Water Pumping Station      
A Foundation 113 - - - - - - - - -
B Superstructural Works 112 - - - - - - - - -
C Installation of E&M Equipment and Commissioning & Testing 102 -   - - - - - - - -
NSR: "BOS" (During Normal Teaching Period)    
    SWL Distance B.C.* CNL       Cumulative Activities      
Activity   (dB(A)) (m) (dB(A)) (dB(A)) (I) (II) (III) (I)+(II) (I)+(III)A (I)+(III)B (I) + (III)C
(I) Water Mains Construction      
A Excavation of Trench / Breaking up Pavement 108 24 75 75 - - - - - -
B Installation of Pipes and Bedding 103 24 70 70 - - - - - -
C Backfilling 108 24 75 75 - - - - - -
D Reinstating Road Surface 105 24 72 72 - - - - - -
(II) Demolishment of Pui O Raw Water Pumping Station      
A General Site Clearance / Demolition Works 114 - - - - - - - - -
(III) Construction of Pui O Raw Water Pumping Station   - - - - -
A Foundation 113 - - - - - - - - -
B Superstructural Works 112 - - - - - - - - -
C Installation of E&M Equipment and Commissioning & Testing 102 -   - - - - - - - -
NSR: "LWT1"    
    SWL Distance B.C.* CNL       Cumulative Activities      
Activity   (dB(A)) (m) (dB(A)) (dB(A)) (I) (II) (III) (I)+(II) (I)+(III)A (I)+(III)B (I) + (III)C
(I) Water Mains Construction      
A Excavation of Trench / Breaking up Pavement 108 13 81 81 - - - - - -
B Installation of Pipes and Bedding 103 13 76 76 - - - - - -
C Backfilling 108 13 81 81 - - - - - -
D Reinstating Road Surface 105 13 78 78 - - - - - -
(II) Demolishment of Pui O Raw Water Pumping Station      
A General Site Clearance / Demolition Works 114 - - - - - - - - -
(III) Construction of Pui O Raw Water Pumping Station   - - - - -
A Foundation 113 - - - - - - - - -
B Superstructural Works 112 - - - - - - - - -
C Installation of E&M Equipment and Commissioning & Testing 102 -   - - - - - - - -
NSR: "LWT2"    
    SWL Distance B.C.* CNL       Cumulative Activities      
Activity   (dB(A)) (m) (dB(A)) (dB(A)) (I) (II) (III) (I)+(II) (I)+(III)A (I)+(III)B (I) + (III)C
(I) Water Mains Construction      
A Excavation of Trench / Breaking up Pavement 108 34 72 72 - - 74 74 73 72
B Installation of Pipes and Bedding 103 34 67 67 - - 71 71 70 67
C Backfilling 108 34 73 73 - - 74 74 74 73
D Reinstating Road Surface 105 34 69 69 - - 72 72 71 70
(II) Demolishment of Pui O Raw Water Pumping Station      
A General Site Clearance / Demolition Works 114 99 69 - 69 - - - - -
(III) Construction of Pui O Raw Water Pumping Station      
A Foundation 113 99 68 - - 68 - - - -
B Superstructural Works 112 99 67 - - 67 - - - -
C Installation of E&M Equipment and Commissioning & Testing 102 99   57 - - 57 - - - -
NSR: "LWT3"    
    SWL Distance B.C.* CNL       Cumulative Activities      
Activity   (dB(A)) (m) (dB(A)) (dB(A)) (I) (II) (III) (I)+(II) (I)+(III)A (I)+(III)B (I) + (III)C
(I) Water Mains Construction *      
A Excavation of Trench / Breaking up Pavement 108 128 10 50 50 - - 75 74 73 63
B Installation of Pipes and Bedding 103 128 10 45 45 - - 75 74 73 63
C Backfilling 108 128 10 51 51 - - 75 74 73 63
D Reinstating Road Surface 105 128 10 48 48 - - 75 74 73 63
(II) Demolishment of Pui O Raw Water Pumping Station      
A General Site Clearance / Demolition Works 114 51 75 - 75 - - - - -
(III) Construction of Pui O Raw Water Pumping Station      
A Foundation 113 51 74 - - 74 - - - -
B Superstructural Works 112 51 73 - - 73 - - - -
C Installation of E&M Equipment and Commissioning & Testing 102 51   62 - - 62 - - - -
* As the receiver's line of sight to the water main works would be blocked by first and second layer of the other buildings and the topographic effect, noise attenuation of 10 dB(A)
 have been considered in the assessment.
NSR: "ALWT1"    
    SWL Distance B.C.* CNL       Cumulative Activities      
Activity   (dB(A)) (m) (dB(A)) (dB(A)) (I) (II) (III) (I)+(II) (I)+(III)A (I)+(III)B (I) + (III)C
(I) Water Mains Construction      
A Excavation of Trench / Breaking up Pavement 108 64 66 66 - - 71 71 70 67
B Installation of Pipes and Bedding 103 64 61 61 - - 70 69 68 63
C Backfilling 108 64 67 67 - - 71 71 70 67
D Reinstating Road Surface 105 64 64 64 - - 71 70 69 65
(II) Demolishment of Pui O Raw Water Pumping Station      
A General Site Clearance / Demolition Works 114 98 70 - 70 - - - - -
(III) Construction of Pui O Raw Water Pumping Station      
A Foundation 113 98 68 - - 68 - - - -
B Superstructural Works 112 98 67 - - 67 - - - -
C Installation of E&M Equipment and Commissioning & Testing 102 98   57 - - 57 - - - -
NSR: "ALWT2"    
    SWL Distance B.C.* CNL       Cumulative Activities      
Activity   (dB(A)) (m) (dB(A)) (dB(A)) (I) (II) (III) (I)+(II) (I)+(III)A (I)+(III)B (I) + (III)C
(I) Water Mains Construction      
A Excavation of Trench / Breaking up Pavement 108 32 72 72 - - 73 73 73 73
B Installation of Pipes and Bedding 103 32 67 67 - - 70 70 69 68
C Backfilling 108 32 73 73 - - 74 74 73 73
D Reinstating Road Surface 105 32 70 70 - - 72 71 71 70
(II) Demolishment of Pui O Raw Water Pumping Station      
A General Site Clearance / Demolition Works 114 137 67 - 67 - - - - -
(III) Construction of Pui O Raw Water Pumping Station      
A Foundation 113 137 65 - - 65 - - - -
B Superstructural Works 112 137 64 - - 64 - - - -
C Installation of E&M Equipment and Commissioning & Testing 102 137   54 - - 54 - - - -
(D2)  Calculation of Construction Noise Levels at Representative Noise Sensitive Receiver BOS (during examination period)
        - Mitigated (Quite Plant)
NSR: "BOS"      
    SWL Distance B.C.* CNL       Cumulative Activities      
Activity   (dB(A)) (m) (dB(A)) (dB(A)) (I) (II) (III) (I)+(II) (I)+(III)A (I)+(III)B (I) + (III)C
(I) Water Mains Construction      
A Excavation of Trench / Breaking up Pavement 102 24 70 70 - - - - - -
B Installation of Pipes and Bedding 100 24 67 67 - - - - - -
C Backfilling 108 24 75 75 - - - - - -
D Reinstating Road Surface 105 24 72 72 - - - - - -
(II) Demolishment of Pui O Raw Water Pumping Station      
A General Site Clearance / Demolition Works 114 - - - - - - - - -
(III) Construction of Pui O Raw Water Pumping Station   - - - - -
A Foundation 113 - - - - - - - - -
B Superstructural Works 112 - - - - - - - - -
C Installation of E&M Equipment and Commissioning & Testing 102 -   - - - - - - - -
List of Abbreviations:
SWL - Sound Power Level
CNL - Corrected Noise Level