Anti-SARS drainage improvement designs for URA projects

The Urban Renewal Authority (URA) and its joint venture partners will adopt improved drainage system designs at four residential projects under construction as a hygiene precaution against SARS.

Chairman of URA's Planning, Development and Conservation Committee, Professor David Lung, told a press conference today (Tuesday) that the URA and its private sector partners, have decided to adopt two alternative improvement designs known as U-trap Refilling Design and Pipes Separation Design.

Either one of the designs will be adopted for the four residential projects which consist of about 4,300 flats in total. The additional cost for the new designs is estimated at about $2 million.

"This represents only a small fraction of the total development costs that run into billions of dollars but it goes a long way in upgrading the hygiene standard of the drainage systems, particularly for the purpose of SARS prevention," Professor Lung said.

Earlier, a Government investigation report has revealed that SARS transmission might be related to the reflux of contaminated air from the soil stack (connected to water closets) through the bathroom floor drain. It was suspected that the reflux has occurred as a result of the drying out of the water seal in the U-trap of the floor drain.

The U-trap Refilling Design is to connect the discharge pipe of the water basin to the U-trap of the floor drain so that each time the water basin is used, the water discharged automatically refills the U-trap and forms a water seal.

The Pipes Separation Design is to separate the floor drain pipework from the soil stack so that the contaminated air in the soil stack will have no chance of flowing across to the floor drain.

The reason that there are two alternative designs is that the U-trap Refilling Design, which is cheaper at about $150 each, is compatible only with a certain type of drainage system. On the other hand, the Pipes Separation Design, which costs about $500 each, is compatible with most drainage systems.

"Both designs are conceptually and technically effective. It is just a matter of drainage system compatibility when choosing between the two," Professor Lung explained.

URA's District Development Director, Mr. Stephen Lam, said the URA would adopt the new designs for all four residential projects under construction with joint venture partners. They include the Tsuen Wan Town Centre project, Kennedy Town New Praya project, Waterloo Road/Yunnam Lane project and Wan Chai Road/Tai Yuen Street project.

"We intend to adopt these or other drainage improvement designs also for all future projects to come and we will continue to watch out for new technology to further upgrade the hygiene standards and features in our new buildings," he added.