Quieter Pipe Lining for Less Night-time Disturbance

Due to land scarcity and the compact nature of the townscape in Hong Kong, there are many public utilities being laid underground to provide the essential infrastructure for public services such as electricity, gas, communication, water supply, drainage and sewerage. In particular, there are over 4,000 km of pipelines being managed by the Drainage Services Department (DSD) over the territory, many of which have served for more than 30 years. A preventive pipe rehabilitation programme has already been in place to tackle the pipe aging problem. However, most pipes are embedded under heavily trafficked roads and populated pedestrian walkways which are very close to residential buildings. Therefore, it is unavoidable that some of the rehabilitation works have to be conducted during the sensitive night hours or on public holidays when there is relatively less traffic. On the other hand, rehabilitation of some pipelines, especially sewers, is only possible during night hours when the sewage flow slows down. As a consequence, more noise intrusions are caused during the rest or sleeping periods of the nearby residents. There is indeed a stringent noise control mechanism by means of the Construction Noise Permit system managed by the Environmental Protection Department (EPD) for protecting people from severe noise disturbance from construction activities. In order to minimize the noise caused by those essential pipe rehabilitation works, the DSD and EPD have jointly evaluated some quiet pipe rehabilitation technologies. The paper will describe the evolution of various pipe rehabilitation technologies, including conventional steam-cured cast-in-place-pipe (CIPP) lining, sleeve lining, geo-polymer lining, Ribline spiral winding etc., and the respective noise characteristics. It will also discuss how noise from the unavoidable construction works is controlled.