Originally Posted by
WillBrink
For as long as the virus can survive on the surfaces of the duct system, yes:
"According to a recent study published in the New England Journal of Medicine, SARS-CoV-2, the virus that causes COVID-19, can live in the air and on surfaces between several hours and several days. The study found that the virus is viable for up to 72 hours on plastics, 48 hours on stainless steel, 24 hours on cardboard, and 4 hours on copper. It is also detectable in the air for three hours."
I'd think the real concern is a duct system blowing covid around a building it pulled in from some location someone had covid, but I don't know how big a concern that is realistically speaking.
Contaminated duct work (especially return air ducting) is the highest risk area as it's pulling air from occupied spaces.
HVAC filter can't stop the virus. It's too small. A MERV 16 HVAC filter (the highest before HEPA) only captures 95% of particulate 0.3 micron and above. The virus itself is down in the 0.1~0.2 micron size. HVAC filters CAN capture the particulate the virus is riding and we suggest MERV 13 and MERV 14 in more critical areas. MERV 13 is the lowest rated filter that will capture particles down to 0.3 micron.
Unfortunately, most homes use 1", 2" and 4" pleats and despite what the filter says, none are actually above MERV 9 in real efficiency (which capture 50% of particles 1.0 micro and above .
Even HEPA filters are not 100% vs small virus particles, but they capture much more particulate.
In theory, the virus captured on the filter will be dead in a few days. We're recommending that buildings go to 100% outside air where ever possible to avoid recirculating air from inside the building. By and large, people are the biggest contributor to inside air quality problems. We're also recommending that buildings change filters much more frequently to keep static pressure inside the system as low as possible to maximize the amount of air we can circulate through a room.
Hospitals and health care centers are scrambling to upgrade their systems now.
- Jeff
“Every record has been destroyed or falsified, every book rewritten, every picture has been repainted, every statue and street building has been renamed, every date has been altered. And the process is continuing day by day and minute by minute. History has stopped. Nothing exists except an endless present in which the Party is always right.” ― George Orwell, 1984
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