Plumbing Systems and the Coronavirus

Based on the latest news about high-rise buildings that have been implicated in recent cases of the COVID-19 coronavirus, it’s clear that transmission paths that would allow for the virus to spread between individual apartment units have been identified. High-rise buildings present unique challenges in plumbing design.

Here it is a simple explanation for everyone to understand:

When toilets in high-rise buildings are flushed, fecal matter and wastewater are discharged into a vertical wastewater pipe, called a “drainage stack.” As the wastewater descends in the stack, it creates pressure changes within the pipe. The wastewater flowing down a stack will push air down ahead of it and drag air behind it, creating both positive and negative pressures within the drainage system. A second vertical pipe called which is called “vent stack,” usually runs parallel to the drainage stack and introduces air into the drainage stack every fifth floor to avert excessive changes that could deplete trap seals and allow contaminated air and aerosols to enter apartments on other floors.

Let’s go back to 2003 when the SARS struck and problems with dry traps were indicated, allowing contaminated air and wastewater aerosols to enter into apartments on lower floors through floor drains.

Sadly for all of us, it seems that the history repeats itself, now with the coronavirus outbreak in Hong Kong. According to the Associated Press, a 2016 Hong Kong Housing Department policy change has allowed tenants in certain high-rise apartments to alter the pipe design in their bathrooms without requiring an inspection by a plumbing official, causing the problem that might have helped spread COVID-19. In one of the apartment units, the vent pipe was completely disconnected inside the bathroom, apparently by the occupant, which provided a pathway for contaminated air to enter the apartment, especially when the bathroom ceiling fans were activated.

Now, the question is could the COVID-19 coronavirus be spread in high-rise buildings in the United States as well? Sadly to say, the answer is yes, but it is unlikely because the U.S has certain plumbing codes, in which any modification to a building’s water, waste or vent system must be performed by a qualified professional and necessitates an inspection by a code official. Also very important to mention, that wastewater stacks and vent pipes are typically hidden behind walls in high-rise buildings, which reduces the opportunity for residents to easily cut into pipes and create unsafe conditions.

Due to the current situation and based on the past experience with SARS, we must note the importance of having any plumbing work and designed completed properly and following the required guidelines in order to keep our residents safe from the disease. Remember that, Improper deviations to building plumbing systems could result in a very significant loss of life and property.