Construction Noise

Sources of noise

• Impact noise – Piling– Hand-held breaker– Excavator mounted breaker– Vibration hammer.

• Engine noise– Compressors– Generators– Trucks

Sound power levels of percussive piling

Piling Method* and Pile Type Sound Power Level (dB(A))

Diesel hammer driving pre-stressed concrete pile 128

Diesel hammer driving steel pile 132

Diesel hammer driving steel sheet pile 132

Drop hammer driving concrete pile 116

Drop hammer driving steel pile 126

Drop hammer driving steel sheet pile 129

Hydraulic hammer (double acting) driving pre-stressed concrete pile

126

Hydraulic hammer (double acting) driving steel pile 129

Hydraulic hammer (double acting) driving steel sheet pile 129

Hydraulic hammer (single acting) driving pre-stressed concrete pile 122

Hydraulic hammer (single acting) driving steel pile 126

Hydraulic hammer (single acting) driving steel sheet pile 126

Internal drop hammer 113

Pneumatic or steam hammer (double acting) driving steel sheet pile

135

Pneumatic or steam hammer (single acting) driving steel pile 130

Sound power levels of powered mechanical equipment

Description Sound Power Level (dB(A))

Air compressor, air flow <= 10m3/min 100

Asphalt paver 109

Bar bender and cutter (electric) 90

Batching plant 108

Breaker, hand-held, mass <= 10kg 108

Ballast tamper, hand-held (electric) 105

Bulldozer 115

Conveyor belt 90

Concrete corer 117

Chipper, hand-held (pneumatic) 112

Concrete lorry mixer 109

Concrete mixer (electric) 96

Concrete pump, stationary/lorry mounted

109

Crane, tower (electric) 95

Compactor, vibratory 105

Derrick barge 104

Level statistics

Legislation

• Piling work: – 5 hours per day max (daytime 07:00 – 19:00)

• General construction work:– Nighttime permit after 19:00

• Product label:– Noise level specified for the product

Legislation

Noise Control Description of Control

General Construction Work Control construction noise from

(a) the use of powered mechanical equipment; and

(b) the carrying out of certain noisy works in designated areas, between 7 p.m. and 7 a.m. and on general holidays, by construction noise permits. Director of Environmental Protection issues permit in accordance with two relevant statutory Technical Memoranda.

Percussive Piling (a) Prohibit percussive piling between 7 p.m. and 7 a.m. and on general holidays; and

(b) restrict the working hours of percussive piling at other times by construction noise permits. Director of Environmental Protection issues permit in accordance with a relevant statutory Technical Memorandum.

Legislation

Legislation

07:00 – 19:00 Leq (30min)

All domestic premises 75 dB(A)

Educational Inst. 70 dB(A)

(during examination) 65 dB(A)

Assessment

• Technical Memorandum on Noise from Construction Work other than Percussive Piling

• Technical Memorandum on Noise from Percussive Piling

• Technical Memorandum on Noise from Construction Work in Designated Areas

Assessment procedures1. Location of the most affected Noise Sensitive Receiver (NSR)2. Determination of the Area Sensitivity Rating (ASR)3. Determination of the Basic Noise Level (BNL)4. Correction for the duration of the Construction Noise Permit (CNP)5. Correction of multiple Permit situations6. Determination of the Acceptable Noise Level (ANL)7. Location of items of Powered Mechanical Equipment (PME)8. Sound power levels for items of Powered Mechanical Equipment

(PME)9. Distance attenuation and summation of noise levels10. Corrections for the effective of barriers11. Corrections for acoustic reflections12. Corrected Noise Level (CNL) at the Noise Sensitive Receiver

(NSR)13. Construction Noise Permit (CNP) issuing procedure

Ref. to Technical Memorandum on Noise from Construction Work Other Than Percussive Piling, HKEPD

Control of construction noise

• concrete and rock breaking machines– control method

• Silenced equipment – pneumatic breaker fitted with mufflers and damping collars– hydraulic breakers– excavator-mounted breaker with sound-proof hammer bracket

• New alternative (quieter) techniques– Concrete crusher– thermal lance– non-explosive demolition agent– pile cracker– cardox (alternative to explosives)

Control of construction noise

• Power units for various types of plants– control techniques

• Noises are generated by internal combustion engines from stationary sources (such as compressors, generators, concrete pumps and welding sets) and earth moving plant (such as excavators m bulldozers, loaders and dump trackers).

– Exhaust noise: improve design and silencers– Cooling noise: better designed fan– Engine noise: enclosures

Control of construction noise

• Noise control practice on site- Selection of quiet equipment- Sitting of equipment- Scheduling of work- Use of acoustic barriers- Use of acoustic machinery enclosures

Control of construction noise

• Noise from pile driving– Percussive pilling (involve the use of impact devices

such as diesel, pneumatic or steam or drop hammers for driving piles into the ground)

• Ringing and impact noise• Exhaust noise

- Non-percussive piling methods (without use of impact pile driver): vibratory hammers, rotary boring etc.

- Quieter proprietary piling methods (internal drop hammers, hydraulic hammers, BSP Impulse pile driver etc.)

Quieter machines for demolition works

Local Case study 1:Widening of Fo Tan Road

Widening of Fo Tan Road

Widening of Fo Tan Road

Observations and AchievementsUnder the normal provision of the Noise Control Ordinance, a contractor is allowed to pile 3 hours a day (using drop hammer producing percussive type noise impact). In this project, the percussive pilling period was reduced to 2 hours after school hours in the afternoon per day. Impact on school was thus reduced. The contractor also took positive actions to administer other noise control measures e.g. prohibiting shouting, whistling etc., to reduce the daytime construction noise.

Local Case study 2: Light Rail Reserve at Tuen Mun

Light Rail Reserve at Tuen Mun

Local Case study 3: West Rail Tai Lam Tunnel

West Rail Tai Lam Tunnel

Local Case study 4: Decommissioning Work at the North Apron of Kai Tak Airpo

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Decommissioning Work

Local Case study 5: Road Repair Work

Road Repair Work

References

• Technical memorandum on noise from percussive piling, HKEPD

• Technical Memorandum for the Assessment of Noise from Places Other Than Domestic Premises, Public Places or Construction Sites, HKEPD

• Technical Memorandum on Noise from Construction Work Other Than Percussive Piling, HKEPD

• Technical Memorandum on Noise from Construction Work in Designated Areas, HKEPD