How MEP could safeguard offices against coronavirus
The standard American office building has probably never felt more like a mystery.
Throughout the design, engineering and construction industries and the business community generally, people are trying to decipher how we can safely return to office buildings while risks from COVID-19 persist. Questions around how to effectively alter offices run a wide gamut: How do you rearrange work spaces and reconfigure interior walkways to properly distance workers? How can you efficiently and safely move workers up through a 28-story office tower? And is it safe to use communal toilet tissue?
Since the coronavirus is spread through respiratory droplets and aerosolized particles, a cluster of questions involve how to adjust HVAC systems. In April, Bala|SVA Consulting Engineers’ COVID-19 Task Force released a white paper about impacts of the virus on the workplace and options to mitigate them.
The paper lays out multiple options for adjusting HVAC systems to lessen virus spread.
“The virus could be constantly reintroduced into the space by people who are asymptomatic so things will have to be done from an operations standpoint right off the bat,” said Charles ‘Chuck’ Kensky, Executive Vice President.
While those options include installing antimicrobial or HEPA filters, better filters alone won’t stop the virus.
“The size of the coronavirus (as well as all viruses) is very small and will pass through almost all filters if independently suspended in the airstream,” the white paper states. “It is understood that the virus will attach to airborne particulate such as dust, which are captured by high efficiency filters.”
Consequently, installing bi-polar ionization technology in a building would charge indoor air, including aerosolized virus, to form ions. The ions would be attracted to dust, smoke, VOCs and other airborne particles, which could be captured by enhanced filtration systems.
Placing UVC lamps at strategic locations within the duct system could destroy microorganisms in the airstream, the white paper states. “However, placement is important since the coronavirus must be exposed for a period of time which requires multiple UVC lamps within the airstream. Manufacturers are recommending exposure for 10 seconds within proximity of the UVC bulb, with some suggesting lamps every six inches.”
Increasing the flow of outside air through a building, including following the standard for infectious-disease rooms that requires two air changes per hour, could further increase the effectiveness of filtration systems. Deactivating demand-control systems that can limit the concentration of outside air, running ventilation systems for longer periods of the day and operating those systems in common spaces, such as shared toilet rooms, continuously could also help lower the risk of contamination, the task force said.
“Toilet rooms will be particularly tricky,” said Bruce Votta, Senior Vice President.
Since coronavirus can be transmitted through respiration, touch and fecal-oral transmission, shared restrooms can present multiple risks. In addition to maintaining distancing and cleaning surfaces after each use, building operators could lower transmission risks in washrooms by installing Far UVC or UVC lamps, the paper states. Such lights, however, would probably only be practical on toilet rooms with individual ceilings. Building owners could consider extending stall walls up to the ceiling but that would likely impact sprinklers, lights and exhaust in the washrooms, Kensky said.
Owners will likely also have to consider revising other building systems in current or future facilities, said Robert Voth, Executive Vice President. “A lot of buildings that we engineer have heat recovery systems where we use exhaust to preheat or precool outside air in order to save energy. There are heat recovery units that are pharmaceutical grade. I think those will become standard in commercial construction to make sure there is no possibility of contamination between the air streams.”