ENG-1993 — Page 455

THE ENVIRONMENT

construction work during weekdays from 7 pm to 7 am and on Sundays and public holidays by means of a construction noise permit system. The department assesses permit applications in accordance with noise criteria and procedures contained in the technical memoranda. The permits generally specify the number and type of equipment that may be used within a certain period of time. The ordinance also bans percussive piling from 7 pm to 7 am on weekdays and at all times on Sundays and public holidays. Percussive piling at other times is controlled by the permit system, which confines operations to specific hours. This system employs a time restriction mechanism so that those piling operations which most affect noise sensitive receivers will work fewer hours. This encourages contractors to use quieter piling methods. During 1993, there were 520 permit applications; 504 permits issued; and five prosecutions.

The department has also started to control specific types of particularly noisy construction equipment. Hand-held percussive breakers and air-compressors, which affect tens of thousands of people when used in building demolition and road works, were the first batch to be controlled. The import, manufacture, supply or use of such equipment for construction purposes must comply with relevant stringent noise emission standards. The equipment must also be fitted with 'green' noise emission labels when being operated. During 1993, there were 2 650 label applications, 2 631 labels issued and 27 prosecutions.

Whenever practicable, the department requires the use of silenced equipment and the adoption of noise reduction measures. The department and the police respond to com- plaints relating to night-time construction work, and carry out inspections. During 1993, there were 1 790 permit applications; 1 482 permits issued; and 34 prosecutions.

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A bill to amend the Noise Control Ordinance to further limit the noise effects of construction work carried out at night and on general holidays was introduced into the Legislative Council. The amendment seeks to essentially ban such activities in populated and other particularly sensitive areas.

Construction under the airport core programme continued and, in 1993, the department issued 170 permits for such work in the restricted hours, with stringent noise mitigation measures. A monitoring programme ensured that construction noise levels were within acceptable limits.

A significant air pollution concern in construction and demolition is the control of asbestos. The Air Pollution Control (Amendment) Ordinance 1993 introduced a full range of measures for the control of materials containing asbestos in buildings and ships; the registration of asbestos consultants, contractors, supervisors and laboratories; and a ban on the import and sale of asbestos (amosite and crocidolite). To pave the way for effective enforcement of the new regulations, the department had installed a transmission electron microscope in 1991. This provides analytical support for the definitive identification of asbestos fibres.

During 1993, the department made 780 inspections, mainly on building demolition and renovation sites, temporary housing areas, housing estates and private buildings, to ensure any asbestos materials involved were handled and disposed of properly in accordance with the requirements of the Waste Disposal (Chemical Waste) Regulation. Its asbestos laboratory, which is covered by the Hong Kong Laboratory Accreditation Scheme, analysed 347 bulk samples and 155 air samples.

Construction and demolition waste, including dredged material, that meet a tight quality specification, may be dumped at sea, subject to licensing controls under the Dumping at

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