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Expert tips to prevent the spread of COVID-19 via sewage pipes


DAB Legislative Councillors Horace CHEUNG, Ben CHAN, Wilson OR and Vincent CHENG recently collaborated with experts from the drainage industry to inspect pipe maintenance problems in a number of public and private housing estates. They concluded that some pipes in private buildings are haphazardly connected, damaged and ageing while differences in pipes design and poor maintenance and management of pipes in public housing have increased the risk of virus transmission and infection. At a recent press conference today, we suggested several short, medium and long-term measures to help prevent the spread of the disease.

Experts C.K. HUNG (Chairman of the Hong Kong Plumbing and Sanitary Ware Trade Association), Raymond C.Y MARK (Vice-Chairman of the Hong Kong Plumbing and Sanitary Ware Trade Association) and Alex POON (Fellow of the British Chartered Institute of Plumbing and Heating Engineering and previous president of the Hong Kong Institute of Environmentalists) all suggest tenants to install a "de-odorising wick" which is low in cost, easy to install and effective at the de-watering point inside the house to prevent the backflow of gas into the house through the dry U-shaped air traps. They suggest installing a "siphon anti-disturbance purification system" in the exhaust ducts outside buildings to filter out viruses directly and reduce the risk of virus transmission through drains.

Wilson OR expects the Housing Department to speed up the inspection process of drainage pipes of 800,000 public housing units within 18 months as pledged. He also urges to inspect and repair at the same time any problematic indoor drainage pipes of households in housing estates. For private buildings, the Buildings Department should also submit a timetable and take the initiative to conduct inspections.

Vincent CHENG says that nearly 30% of the 21,000 buildings over 30 years old in Hong Kong are in Kowloon West. Kowloon West also accounts for half of the nearly 7,000 old buildings that are 50 years old or above. The reasons why residents in Kowloon West were often required to take enforced quarantine during the epidemic are the large number of sub-divided flats with pipes that are illegally connected with external walls, drainage pipes that are broken or loopholes in the old legislation that were used to connect drainage in an open way that is dangerous. The virus could then easily spread through windows. He requested the government to set up a task force coordinating the inspection and maintenance of pipes in private buildings across the HKSAR.

Currently many "three-nil” buildings" are at risk of virus transmission via drains, Ben CHAN hopes the authorities will conduct drains maintenance before charging the owners and provide subsidies to owners with financial difficulties.

In the long run, the government should introduce a registration system for drainage workers teaching them about safe and qualified drainage supplies and proper installation; require mandatory inspection of drains in buildings every 15 years to ensure pipe safety; review existing guidelines for the industry, and study the introduction of new technologies to improve pipe safety.

Recently, CE Carrie LAM responded to a question from Wilson OR promising to study with relevant research institutions how to best utilize technology to solve existing problems. The DAB would continue to follow up in the Legislative Council and liaise with the Transport and Housing Bureau, the Development Bureau, the Environment Bureau and the Innovation and Technology Bureau to implement various measures of preventing virus transmissions through drainage pipes. ​


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