ENG-1994 — Page 482

THE ENVIRONMENT

424

Construction and Demolition

The noise and vibration of the percussive pile-driver, once so characteristic of Hong Kong's massive construction programme, is now minimised by restrictions on its operations. The construction industry is no less active, however, and still generates noise, smoke and dust. It also produces vast quantities of solid waste that need safe disposal.

The Environmental Protection Department controls the operation of powered mechanical equipment in general construction work from 7 pm to 7 am on weekdays and at all times on Sundays and public holidays by means of a construction noise permit system. The permits generally specify the number and type of equipment that may be used within a certain period of time. Percussive piling is banned from 7 pm to 7 am on weekdays and at all times on Sundays and public holidays, and is controlled at other times under 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 1994, there were 610 permit applications; 600 permits issued; and four prosecutions for breaches.

Other controls operate on specific types of particularly noisy construction equipment. Hand-held percussive breakers and air compressors, the use of which affects tens of thousands of people, 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, stating the noise level produced. During 1994, there were 1 700 label applications, 1 705 labels issued and 11 prosecutions.

Whenever practicable, the department requires the use of silenced equipment and adoption of noise reduction measures.

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 will be introduced into the Legislative Council in early 1995. The amendment seeks essentially to ban such activities in populated and other particularly sensitive areas.

As existing controls over construction noise fall short of public demands for a quieter environment, legislation was proposed to extend the controls to cover manual construction activities, such as rubble disposal, hammering, and the erection and dismantling of form- work or scaffolding, in populated areas. This, together with tightened controls over certain particularly noisy, powered mechanical equipment, would have the effect of banning virtually all non-essential noisy construction activities in built-up areas during night-time and holidays. Plans have also been formulated to phase out the use of diesel hammer pile- drivers to further reduce daytime construction noise.

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, including 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 the 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.