"Black toilets" have far-reaching disaster, the government must restore the sun and air

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Written by: Commentary Editing Room

2020-08-14 06:30

Since the outbreak of the new crown pneumonia, Hong Kong people have paid special attention to the spread of the virus in the toilets. In March, several residents of Changkang Village, Tsing Yi, who were sitting at their flats were infected, causing panic. Architects, surveyors, and doctors have successively reminded residents to strengthen toilet hygiene, such as filling the U-shaped water trap with water from time to time, and covering the toilet panel when flushing to maintain air circulation. Residents living in black toilets are more worried that the ventilation arrangements are more likely to spread drugs. Recently, Li Guoxing, president of the Hong Kong Institute of Architects, appealed to all walks of life to pay attention to "black toilets", emphasizing the importance of natural ventilation.

In 1997, the Buildings Department issued a practice note, accepting the use of artificial lighting and mechanical ventilation in bathrooms and toilets, residential units can build "black toilets". The picture shows the floor plan of the Johnsville Harbour House in North Point, completed in 2003. (Photo of Fax Agency)

Revised since 1997

There is no window in the black toilet, and by opening the air extraction system, negative air pressure is formed in the room and water vapor and exhaust gas are removed. However, this also draws air from the floor to the toilet. If the residents of other units become sick and the water trap dries up, viruses and bacteria may also be spread to other floors through the pipeline.

In this regard, residents can add hundreds of pages to the toilet door, or leave a gap when closing the toilet door. When the exhaust fan is activated, the air in the dining room will be drawn into the toilet through the louver or door gap to avoid drawing air into the water level. Of course, the black toilet has a strong ventilation system, and residents have to fill the pipes more frequently.

The emergence of black toilets stems from the Buildings Department’s waiver of the lighting and ventilation requirements for toilets in 1997. As long as they meet certain conditions, including the installation of mechanical ventilation facilities with five air changes per hour and the use of outdoor air for ventilation, the cross-section of the air outlet is at least One twentieth the area of ​​the bathroom.

According to the Buildings Department, this change stems from making residential design more flexible and adapting to advances in ventilation technology. In fact, the patios of ordinary residential buildings are not always clean. Oily fumes and sewage are brought into the house through pipes, walls or wind. Some residents close the bathroom windows for a long time, and the room only transmits light and does not allow air. There is no window in the toilet, or these shortcomings can be eliminated. For real estate developers, if the unit has a built-in toilet, the outdoor landscape can be reserved for the living room and bedroom, and the unit value is higher.

The Institute of Architects believes that the epidemic will allow everyone to reflect on the design of the "black toilet". (Profile picture)

Ventilation pipes may be unmaintained

The toilet has a window, even if it is not always open, it can always increase the chance of air circulation, but the black toilet cannot. In addition, the black toilet is a confined space. Residents tend to use the air extraction system for a long time. The increase in electricity bills may be small, and the fatigue of motors or components may be large. In addition, the suction pipe itself contains moisture, which will easily accumulate bacteria and viruses. It is worth noting whether the exhaust pipes are regularly cleaned and maintained? There are public and private parts of the pipeline. The private part must be managed by the residents themselves, while the central pipeline must be managed by the property management company.

Cleaning the private part of the pipe is not as easy to assemble and disassemble like an exhaust fan, or requires professional engineering personnel to maintain it, which will cause more trouble for the residents. Regarding the central duct, the Buildings Department only stated that the engineer’s work notes on the ventilation arrangements of the building only stated that "the "best" is to inspect and clean the ventilation ducts annually." The use of the word "best" is not like mandatory window inspection or building inspection, but a rigid rule. If the property management company does not arrange cleaning, it will not be responsible, but it will increase the health risks of the residents.

As a preventive measure, the Buildings Department will, through the appointment of a consulting company, take the initiative to inspect the external wall drainage pipes of more than 20,000 private residential and mixed-use target buildings in Hong Kong. (Photo of Development Bureau)

Building a building must consider the long-term

In the real estate program of the TV station, the host introduces residential units and often prefers toilets with windows. For example, it is described as "a window, not a black toilet", and "a window helps to remove moisture." Nowadays, even professionals warn that the pattern of black toilets is harmful in the long run. In addition to Li Guoxing, the president of the Institute of Architects mentioned above, He Juye, the former president of the Institute of Surveyors, also said in an earlier interview that black toilets caused more pipes to be installed indoors and damaged. It is harder to detect and maintenance is harder. More importantly, damage and aging become more obvious after a few decades. The current design "does not take into account what will happen decades later."

Weighing the pros and cons, even if a toilet with a window is not perfect, considering the difficulty of ventilation, detection of pipe problems and maintenance, window toilets are always better than black toilets. Hong Kong is densely populated and concentrated in multi-storey buildings, which can easily breed and spread viruses and bacteria. Residents and industry members are now also calling for a review of black toilets, and even a more macro-level review of the building’s sanitation. The government must respond by reviewing itself as well as telling real estate developers about the pros and cons and abandoning black toilet design. With regard to the existing black toilets, the Buildings Department must tighten controls, especially the cleaning and maintenance requirements. The life span of a building can be dozens of years, and the layout, equipment, and materials must meet the long-term needs, so that people can live in peace of mind.

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