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REFURBISHMENT OF ..... - SECTION 61 AGREEMENT

Scope of Report

To provide information pertaining to noise and vibration for inclusion in a Section 61 Agreement.

1. INTRODUCTION

1.1 .... operate from .....

1.2 The existing wooden dolphins need to be replaced with metal piled dolphins.

1.3 This report predicts levels of noise and vibration expected from the piling works and contains comments for inclusion in the Section 61 Agreement.

2. SECTION 61 AGREEMENT

2.1 Noise and Vibration Control Limits

2.1.1 Environmental Health propose the following noise and vibration limits/restrictions:

  • Maximum of 75 dB(A) LAeq,10 hours measured 1 m from the façade of any occupied building.
  • Maximum of 1 mm/s Peak Particle Velocity (measured in any one direction) at the foundations of an occupied residential building.
  • Maximum of 3 mm/s Peak Particle Velocity (measured in any one direction) at the foundations of an occupied commercial building.

2.1.2 It was agreed that and be designated commercial buildings, and that the be designated a residential building, as the landlord occupies a flat on the premises.

2.2 Prediction of Noise and Vibration Levels

2.2.1 A plan of the site is shown in Figure 1.

2.2.2 Noise and vibration levels are predicted for three locations (A - C) along the river wall. Noise levels are calculated as a 10-hour LAeq based on the following operation duration's, as requested by the Contractor:

  • Impact piling - dependant upon the noise level
  • Vibration piling - 0.5 hours
  • Crane hoisting/lowering - 3 hours
  • Crane idling - 7 hours
  • Welding Machine - 4 hours

2.2.3 It is important to note that these piling operations are dependent on tidal movements of the river, and therefore these duration's are maximums desired by the Contractor.

2.2.4 Vibration is predicted using the manufacturer's data for the hammer energy, and the following conservative relationship from Attewell et al. (1991):

    Where: v = simulated resultant PPV at base of foundation of a structure (mm/s)

    E = pile energy input/cycle (J)

    r = surface distance (m)

2.2.5 The predictions use the maximum energy per cycle (as quoted by the manufacturer) and therefore represent a higher level of vibration than would normally be expected.

2.2.6 It is acknowledged that the Attewell formula does not predict the vibration magnitude in any one direction separately, as the local authority limits are expressed. However, we are unaware of any more suitable expressions. It could be assumed that the simulated resultant PPV is acting all in one direction, but this is likely to be an over-estimation. PPV in any one direction can be determined following monitoring.

2.2.7 Noise levels are predicted using the manufacturer's data for the source level, and the procedure described in BS 5228 Part 1. Where no manufacturer's data exists for a source level, values for generic plant are used, or that provided by the Contractor.

2.2.8 It is important to note that the predictions are based on data provided by the manufacturer's of the piling hammers. Noise and vibration are particularly site specific, and therefore these predictions can only serve as a guide.

Table 1: Vibration Predictions

Pile Energy Input / cycle (J)
Source of data
Piling Location
A
B
C
Surface Distance (m)
PPV (mm/s)
Surface Distance (m)
PPV (mm/s)
Surface Distance (m)
PPV (mm/s)
Impact hammer
23544
Manufacturer
West Dolphin
72
0.6
50
1.1
55
1.0
East Dolphin
52
1.1
45
1.3
80
0.5
Vibro-hammer
5700
Manufacturer
West Dolphin
72
0.2
50
0.4
55
0.3
East Dolphin
52
0.4
45
0.4
80
0.2

NOTES: PPV is simulated resultant. This is a different parameter from the PPV in any one direction, as used by the local authority limits. PPV in any one direction can be determined following monitoring.

Impact Hammer is a Dawson HPH 2400.

Vibro-hammer is a PVE 2316 VM.

Pile energies are maximum possible.

Table 2: Noise Predictions

RECEIVER LOCATION A - Plant at Western Dolphin
Plant
Activity LAeq at 10m (dBA)
Source of data
Distance to Receiver (m)
Distance Correction (dB)
Façade Correction (dB)
Corrected Activity LAeq at Receiver (dBA)
Maximum Operational Time in 1 Working Day (hours)
LAeq,10 hour at Receiver (dBA)
Impact Hammer
93.8
Manufacturer
72
-17.1
+3
79.7
1
72
Vibro-hammer
88
73.9
0.5
Welding Machine
82
67.9
4
Crane Hoisting / Lowering
82
67.9
3
Crane Idling
62
47.9
7
RECEIVER LOCATION B - Plant at Western Dolphin
Plant
Activity LAeq at 10m (dBA)
Source of data
Distance to Receiver (m)
Distance Correction (dB)
Façade Correction (dB)
Corrected Activity LAeq at Receiver (dBA)
Maximum Operational Time in 1 Working Day (hours)
LAeq,10 hour at Receiver (dBA)
Impact Hammer
93.8
Manufacturer
50
-14.0
+3
82.8
1
75
Vibro-hammer
88
77.0
0.5
Welding Machine
82
71.0
4
Crane Hoisting / Lowering
82
71.0
3
Crane Idling
62
51.0
7
RECEIVER LOCATION C - Plant at Western Dolphin
Plant
Activity LAeq at 10m (dBA)
Source of data
Distance to Receiver (m)
Distance Correction (dB)
Façade Correction (dB)
Corrected Activity LAeq at Receiver (dBA)
Maximum Operational Time in 1 Working Day (hours)
LAeq,10 hour at Receiver (dBA)
Impact Hammer
93.8
Manufacturer
55
-14.8
0
79.0
1
71
Vibro-hammer
88
73.2
0.5
Welding Machine
82
67.2
4
Crane Hoisting / Lowering
82
67.2
3
Crane Idling
62
47.2
7

RECEIVER LOCATION A - Plant at Eastern Dolphin
Plant
Activity LAeq at 10m (dBA)
Source of data
Distance to Receiver (m)
Distance Correction (dB)
Façade Correction (dB)
Corrected Activity LAeq at Receiver (dBA)
Maximum Operational Time in 1 Working Day (hours)
LAeq,10 hour at Receiver (dBA)
Impact Hammer
93.8
Manufacturer
52
-14.3
+3
82.5
0.6
73
Vibro-hammer
88
76.7
0.5
Welding Machine
82
70.7
4
Crane Hoisting / Lowering
82
70.7
3
Crane Idling
62
50.7
7
RECEIVER LOCATION B - Plant at Eastern Dolphin
Plant
Activity LAeq at 10m (dBA)
Source of data
Distance to Receiver (m)
Distance Correction (dB)
Façade Correction (dB)
Corrected Activity LAeq at Receiver (dBA)
Maximum Operational Time in 1 Working Day (hours)
LAeq,10 hour at Receiver (dBA)
Impact Hammer
93.8
Manufacturer
42
-12.5
+3
84.3
0.6
75
Vibro-hammer
88
78.5
0.5
Welding Machine
82
72.5
4
Crane Hoisting / Lowering
82
72.5
3
Crane Idling
62
52.5
7
RECEIVER LOCATION C - Plant at Eastern Dolphin
Plant
Activity LAeq at 10m (dBA)
Source of data
Distance to Receiver (m)
Distance Correction (dB)
Façade Correction (dB)
Corrected Activity LAeq at Receiver (dBA)
Maximum Operational Time in 1 Working Day (hours)
LAeq,10 hour at Receiver (dBA)
Impact Hammer
93.8
Manufacturer
80
-18.1
0
75.7
0.6
66
Vibro-hammer
88
69.9
0.5
Welding Machine
82
63.9
4
Crane Hoisting / Lowering
82
63.9
3
Crane Idling
62
43.9
7

2.3 Mitigation and Control Measures

2.3.1 It is understood that the Contractor will adopt the following mitigation and control measures:

2.3.2 All plant will be located on a barge adjacent to the dolphin being piled. This is some 40 m from the river bank, and will therefore minimise the impact of noise from the plant to the local residents.

2.3.4 Plant and piles will be transported to and from the site by river, therefore minimising the impact to the local residents.

2.3.5 The impact piling hammer will only be used in 'noise reduced mode'.

2.3.6 The Contractor will comply with the requirements of the Control of Pollution Act 1974, the Environmental Protection Act 1990, the Noise at Work Regulations 1989 and the Health and Safety at Work Act 1974.

2.4 Noise and Vibration Monitoring

2.4.1 At a meeting with a representative of ... Environmental Health (Mr ....11/08/00), the following noise and vibration monitoring locations were agreed:

  • Vibration V1: On the paving slabs of the garden to the PH. (Although a basement location is preferred, this is not possible as the pub will be closed for refurbishment during the piling works).
  • Noise N1: In the garden on the PH.
  • Vibration V2: At the base of beside entrance gate.

2.4.2 Vibration monitoring will be undertaken using two NOMIS 5000 Series seismographs. These will be set to print the highest PPV occurring in any one direction every 30 minutes throughout the working day.

2.4.3 Noise monitoring will be undertaken using one Bruel & Kjaer 2236E sound level meter. This will be set to measure the LAeq for the working day. The unit will also log the hourly LAeq. Printouts will be made of these results at the end of each day.

2.4.3 Copies of measurement reports will be sent to EH within two working days of the measurements being taken.

2.4.4 Specifications for the monitoring equipment is included in Appendix A.