Noise is one of the concerns that had been raised by the public on the proposed MY Rapid Transit (MRT) project in the Klang Valley.

Measures are planned and designed by the project proponent (MRT Corporation) and the Project Delivery Partner (designers and project management team in particular) to address potential noise (and vibration) pollution.

One of the noise (and vibration) concerns from this project that could potentially affect the public is during the construction stage of the MRT.

Noise generation in any infrastructure construction project is primarily from heavy vehicles, excavation and demolition works (from tractors, jack hammers, etc), mobile generator sets and piling works.

To reduce noise generation, the construction of the MRT will be using a number of modern equipment to ensure the serenity of the neighbourhood is retained.

For instance, modern mobile generators will be used and they are all come fitted within an acoustics enclosure (sound-proofed units) which render the genset no noisier than a typical car.

This then leaves heavy vehicles, earth clearing equipment and occasional jack hammers to be the only major noise sources from MRT construction that may affect nearby houses.

There is a mandatory requirement stipulated by the Department of Environment (DOE) for the MRT project that noise (and vibration) shall be monitored during construction.

Based on the requirements, MRT is now installing noise (and vibration) measurement instruments at major construction site(s) for continuous automatic or manual monitoring of noise (and vibration) from the construction.

These works shall be undertaken by an independent test laboratory. Results of the monitoring are to be submitted to DOE forming part of the mandatory Environmental Management Plan for this project.

DOE has also stipulated in its Environmental Impact Assessment (EIA) approval for the MRT project that any construction activity which may result in noise disturbance can only be undertaken between 8am and 7pm.

And such works cannot be undertaken on Sundays and public holidays; except under exceptional circumstances (for example, works dictated by public safety such as launching of beams, or emergency works).

To comply to the DOE, the MRT Corporation has provided with the following mitigation measures during construction:

• Limiting activities that may generate high noise and vibration levels from 8am to 6pm; with no construction works on Sunday and public holidays;

• Use of low noise and vibration piling methods;

• Use of diesel generator sets housed in acoustics enclosures fitted with silencers;

• Erection of hoarding and barriers at construction sites for shielding of noise from the construction site;

• Use of portable semi-enclosures for partial screening of equipment and noisy work process; and

• Managing traffic flow and movement of heavy vehicles.

In sensitive areas, measures planned by the Project Delivery Partners include additional baseline noise and vibration monitoring prior to construction; projection and assessment of likely noise and vibration that may occur in these areas; and putting in place all feasible mitigation measures.

These measures are planned and to be implemented over and above the Detailed EIA that had been undertaken where such monitoring and assessment are sites specific.

The above ensure that there shall be minimal to no noise (and vibration) disturbance at night and on non-working days and any such noise disturbance are limited to daytime working days only.

Sources of noise and vibration generation and its propagation to the surrounding areas shall also be minimised.It is apparent that all feasible technical and administrative mitigation measurements have been planned into this project.

In the event that construction noise (and vibration) exceeds the DOE stipulated limits, or are substantially higher than the existing ambient, DOE can exercise its regulatory powers provided in the EIA Approval for compliance, which can also include a monetary fine.

In instances where there are risks to public safety, stop-work orders can also be issued by the authorities until such time the risks are addressed.

PROF IR DR SALMAN LEONG is Professor/Director of the Institute of Noise & Vibration, Universiti Teknologi Malaysia, UTM