As guardians of the indoor air we breathe, HVAC contractors and technicians stand alongside public health workers in the fight against coronavirus (COVID-19). As with the SARS outbreak in 2003, the airborne nature of the new coronavirus (part of the same family of viruses as SARS) puts the epidemic — and its prevention and containment — front and center for HVAC professionals.
For concerned clients, the priority will be keeping their employees, their facilities, and their families safe. Contractors should be aware of what the available technologies are and represent them in an honest and transparent way while noting that disease prevention cannot be solved by HVAC alone.
“You can't guarantee that because you've installed a certain product, you've prevented infections from occurring, because there are multiple ways that they can be transmitted,” said William Bahnfleth, ASHRAE presidential member. “If I were a contractor, I’d be prepared to suggest to a homeowner other things they might do that are not necessarily HVAC-related that would reduce infection risk.”
ALL ABOUT AIRBORNE TRANSMISSION
One of the big questions about coronavirus — especially from an HVAC perspective — is how significant of a role airborne transmission plays in its spread. As professor of architectural engineering at the Pennsylvania State University and founding director of its Indoor Environment Center, Bahnfleth is well versed in what’s been published recently on that topic.
“The current consensus is that it's predominantly large droplet transfer,” he reported. This means droplets too large to remain airborne that are spread through coughing and sneezing within a fairly close range of other people. The Center for Disease Control (CDC) puts this range at about six feet.
Coronavirus
“If I were to cough or sneeze in your direction unprotected, some of the virus-containing droplets coming out of my mouth or nose might enter your mouth, eyes, or nose and cause an infection,” he said.
Another mode of transmission involves intermediate surfaces. For example, an infected person might cough or sneeze into their hand and then leave infective material on a door knob that someone else might touch and then transfer it to their own mouth or eye.
“But there's also the potential for airborne transmission,” Bahnfleth said. “And if viruses that are viable are in those droplets that you're producing, some of them will be small enough that they will stay airborne for a long time. So, it's not impossible that infectious particles in the air could stay aloft long enough to be collected, say at the return grille of an HVAC system, go through a duct, and infect someone in a different space.”
“Because there are three distinct ways of transmitting an infection,” he added, “even perfect control of airborne pathogens would not eliminate all risk.”
For concerned clients, the priority will be keeping their employees, their facilities, and their families safe. Contractors should be aware of what the available technologies are and represent them in an honest and transparent way while noting that disease prevention cannot be solved by HVAC alone.
“You can't guarantee that because you've installed a certain product, you've prevented infections from occurring, because there are multiple ways that they can be transmitted,” said William Bahnfleth, ASHRAE presidential member. “If I were a contractor, I’d be prepared to suggest to a homeowner other things they might do that are not necessarily HVAC-related that would reduce infection risk.”
ALL ABOUT AIRBORNE TRANSMISSION
One of the big questions about coronavirus — especially from an HVAC perspective — is how significant of a role airborne transmission plays in its spread. As professor of architectural engineering at the Pennsylvania State University and founding director of its Indoor Environment Center, Bahnfleth is well versed in what’s been published recently on that topic.
“The current consensus is that it's predominantly large droplet transfer,” he reported. This means droplets too large to remain airborne that are spread through coughing and sneezing within a fairly close range of other people. The Center for Disease Control (CDC) puts this range at about six feet.
Coronavirus
“If I were to cough or sneeze in your direction unprotected, some of the virus-containing droplets coming out of my mouth or nose might enter your mouth, eyes, or nose and cause an infection,” he said.
Another mode of transmission involves intermediate surfaces. For example, an infected person might cough or sneeze into their hand and then leave infective material on a door knob that someone else might touch and then transfer it to their own mouth or eye.
“But there's also the potential for airborne transmission,” Bahnfleth said. “And if viruses that are viable are in those droplets that you're producing, some of them will be small enough that they will stay airborne for a long time. So, it's not impossible that infectious particles in the air could stay aloft long enough to be collected, say at the return grille of an HVAC system, go through a duct, and infect someone in a different space.”
“Because there are three distinct ways of transmitting an infection,” he added, “even perfect control of airborne pathogens would not eliminate all risk.”
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