Amid the epidemic, everyone should go further to protect themselves and their family. Apart from keeping home environment clean, maintaining the “health” condition of drainage pipes is of paramount importance. During the fight against the epidemic, members of the public should pay attention to whether indoor drainage pipes are in good condition and traps are functioning properly to guard against viruses. This time, I have specially invited a colleague from the Buildings Department (BD) to brief on the importance of “healthy” traps and the ways of maintaining their normal functioning.

Preventing foul odour and viruses from entering the premises

Traps are usually connected to sanitary fitments in a residential flat and play a vital role in the drainage system. Building Surveyor of the BD, Ms WONG Shu-wan, says that all sanitary fitments discharging sewage, such as wash basins, wash-up sinks, floor drains, water closets, bathtubs, shower trays and washing machines, need to be equipped with traps. A trap serves to prevent foul odour and viruses in drainage pipes from entering the premises by means of water seal that is formed when the trap is filled with water.

Floor drains are easily overlooked

As sanitary fitments in bathrooms and kitchens are frequently used in daily life, water seal in their traps are not subject to drying up. However, floor drains, which are usually located in kitchens, toilets and bathrooms, are easily overlooked. If floor drains have not been used for a long time or occupants forget to pour water into them regularly, the water seal in their traps will evaporate gradually and lose the capability for preventing foul odour and viruses from entering the premises.

Pouring water into traps on a weekly basis

Ms WONG Shu-wan says that if an exhaust fan is turned on in a closed bathroom the negative air pressure so created may draw foul odour and viruses into the premises through floor drains in the case where their traps run dry. Therefore, occupants should have a good habit of pouring about half a litre of water into each floor drain at home once a week to ensure water seal in the trap functions properly. It is important to keep this practice up, in particular amid the epidemic.

She also suggests that members of the public should conduct regular checks on drainage pipes. If drainage pipes are found to be leaking, damaged, blocked or emitting foul odour, they should immediately arrange for qualified registered contractors to check and repair the drainage pipes. Moreover, owners should not carry out illegal alteration works to the drainage pipes, in particular the traps and anti-syphonage pipes/anti-syphonage air valves. When the water closet in the upper or lower flat is being flushed, “siphonage effect” will occur in the drainage pipe, which is possibly able to suck out the water seal in the trap, thus allowing foul odour and viruses to enter the premises. Similar to an anti-syphonage pipe, an anti-syphonage air valve serves to prevent the loss of water seal in the trap due to “siphonage effect”. If the trap of a wash basin, a wash-up sink or a washing machine needs to be replaced, a trap with an anti-syphonage air valve should be purchased.

Notifying the BD when altering main drainage pipes

Separately, it is not uncommon for households in Hong Kong to convert bathtubs into shower trays. Members of the public should bear in mind that a trap must be fitted to the drainage pipe when making such conversion. Ms WONG Shu-wan reminds members of the public not to carry out illegal alteration works to drainage pipes when altering the layout of their kitchen or bathroom. If it is necessary to alter a main drainage pipe or a branch pipe, such as in the case of erecting a new drainage pipe, a qualified Registered Contractor must be appointed to carry out the works and notify the BD as required under the Minor Works Control System.

Continuing to organise Building Safety Online Seminars

Over the past year, the BD has organised several Building Safety Online Seminars to provide information about healthy drains for members of the public, building practitioners, owners’ corporations and property management companies. Our colleagues were also invited to attend building management courses co-organised by the Home Affairs Department, with a view to providing seminars on healthy drains to participants. The BD will continue to organise Building Safety Online Seminars. Interested parties may visit the BD’s Facebook page for updates.

Last year, the BD produced the pamphlet “What you need to know about drainage pipe maintenance” and a number of announcements in public interests on healthy drains which have been translated into nine ethnic minorities (EM) languages for the EM community.

Construction of community isolation facilities in full swing

In view of the current severe epidemic situation, the Development Bureau (DEVB), with the full support of the Central Government and the all-out co-ordination by the Liaison Office of the Central People’s Government in the Hong Kong Special Administrative Region, has led its works departments to collaborate closely with the contractors, and the construction of eight community isolation and treatment facilities with the Mainland’s support is in full swing. Thanks to the efforts made by the construction team which worked round the clock braving wind and rain, coupled with the intensive co-ordination by the professional team comprising staff members from the works departments under the DEVB, the construction of the community isolation facility (CIF) in Tsing Yi, providing about 3 900 additional beds for emergency isolation, was completed in just seven days and handed over from the contractor to the HKSAR Government on 1 March for immediate operation.

The site formation works have been completed at the former site of the Boxes in San Tin and the modular homes used for isolation are being assembled. It is expected to be the next CIF to commence operation.

Pulling wisdom and efforts together

In the face of the severe epidemic situation, the DEVB and its works departments pool their wisdom and efforts together to fulfill the mission of constructing the facilities at other locations as soon as possible, so as to relieve the pressure for community isolation and treatment and stabilise the epidemic situation early.