HVAC Co-Vid19 Issue: AC/Hot Air Circulation in Restaurants, Airplanes, etc.

D107

Just saw a news item online that in at least one restaurant the AC or Heat air circulation is thought to have infected 9 customers from one customer. Everybody's talking about re-opening public places, etc. but what's your take on how to solve this problem. Even if you go back to fans only, it's probably the same issue. People can't keep their masks on when they're eating; anyway the virus could enter via their eyes as well. Seems like the vaccine is the only answer---but until then?

pecmsg

D107 said:

Just saw a notice online that in at least one restaurant the AC or Heat air circulation is thought to have infected 9 customers from one customer. Everybody's talking about re-opening public places, etc. but what's your take on how to solve this problem. Even if you go back to fans only, it's probably the same issue. People can't keep their masks on when they're eating; anyway the virus could enter via their eyes as well. Seems like the vaccine is the only answer---but until then?

the beauty of OnLine reporting is theres NO accountabilty

I call B S !

weil_fail

in theory, UV can kill viruses. however, I don't know if anyone has tested UV HVAC add-ons to see if they would make an impact. also, one of the reasons certain viruses (flu) don't spread as well in the summer is in part due to the amount of moisture in the air. apparently, viruses stay airborne longer when it's dryer. so, in theory, a hotter and more humid room would help; but, again, there isn't enough science to know whether that would actually help with COVID-19.

D107

Here's something that Ashrae released; there's plenty of other fairly reputable questioning of these issues online.

https://facilityexecutive.com/2020/02/coronavirus-and-hvac-ashrae-releases-guidance-material/

And here's the original article, which seems to be legit:

https://people.com/health/air-conditioning-coronavirus-spreader-9-people-infected-at-restaurant/

nibs

My microbiologist friend says if an infected person is coughing or 'speaking wetly' the viral droplets can indeed get sucked into a duct and spread throughout the room/building, unless there are adequate filters in the system.

Jamie Hall

Actually, I wouldn't be that surprised if the thing couldn't spread through air conditioning/forced air heating systems, at least under certain conditions. It might also spread in aircraft, although less widely due to the way they are ventilated. After all, it is a coronavirus, and most coronavirus do spread fairly easily -- which is one reason why the common cold is, well, common.

UV disinfection might work, provided there is enough exposure time. UV disinfection systems are a maintenance nightmare, but in some situations might be warranted.

But... before we start thinking about that, are we really sure we have a problem here? Before people have hysterics, first we need to have some solid information -- which we don't have anything close to -- as to what the actual mortality rate is; some information I have seen recently suggests it may be as little as one fiftieth of the reported rate. That brings it right down to many of the other ills that mankind falls prey to -- and which we accept, at least after a fashion Then we need to consider what -- even at the reported mortality rates -- is the actual effect on life expectancy. Again, some information I've seen suggests that the presence of this thing may knock as much as a few months to a year off your probable life expectancy. Is this such a big deal? We all leave by the same gate -- there are no survivors in this game of life. Something which seems to have been forgotten.

Mind you, I'm not suggesting that prudent sanitary measures be overlooked. There's much to be said, for instance, for washing one's hands. There always has been. There's much to be said for being unselfish and staying home if one has a communicable disease ('flu, cold, Covid-19, doesn't matter). Again, there always has been -- though in these modern times we seem to have an inordinate number of people who don't care.

There is nothing meritorious to be said for claiming that the sky is falling and the end is near -- and taking excessive measures based on fear.

pecmsg

nibs said:

My microbiologist friend says if an infected person is coughing or 'speaking wetly' the viral droplets can indeed get sucked into a duct and spread throughout the room/building, unless there are adequate filters in the system.

Your friend is correct, now that small water droplet has to go down the entire return without sticking to any surface, Get past a filter that again probably has a ton of dust particle's that attract moisture, thru the A/C evaporator that OK if running is dripping wet, NOW it is in a very humid environment close to 100% until deposited into the room being conditioned.

Care to pick the Pick 6 at Gulfstream Park tomorrow......……….You've got a better chance.

Zman

D107 said:

Here's something that Ashrae released; there's plenty of other fairly reputable questioning of these issues online.

https://facilityexecutive.com/2020/02/coronavirus-and-hvac-ashrae-releases-guidance-material/

And here's the original article, which seems to be legit:

https://people.com/health/air-conditioning-coronavirus-spreader-9-people-infected-at-restaurant/

A People magazine article with a 2nd, 3rd, or 4th hand story about a restaurant in China is legit?

The majority of the HVAC systems I see are not functioning correctly, particularly in regard to outside air.

I attended a webinar this morning about ionizing generators for HVAC systems. Very interesting stuff.
.

SuperTech

I was sick with the virus at the end of February. My girlfriend caught it from me, we live together. I didn't know what it was at the time because it was before it was so widespread in NY. I became concerned about the possibility of spreading it to customers whose systems I worked on.

I had an older female customer who insisted on having me eat dinner with her family after I cleaned and repaired a plugged oil furnace. I spent four hours at the house not feeling 100%. This was the last call I did before missing a week of work with the virus. I was sure I must have spread it to someone who was there. I went back there yesterday and found out that no one who was there became sick somehow.

Jamie Hall

Sounds like us, @SuperTech . One of the guys my daughter works with picked it up around the end of February, she got it and a couple of other guys in the shop (one of whom with diabetes wound up in the hospital with pneumonia, but this was before we knew what it was, so he survived OK) and she brought it home to me. Not much fun, was it? But not a whole lot worse than a bad case of 'flu.

D107

@Zman People Magazine was reporting on a study (linked in the article) to be published in a journal from the Centers for Disease Control. The same study, which is a field study and self-admittedly not definitive was reported on by the New York Times and includes quoted opinions from the Medical Director of Infection Prevention and Health System Epidemiology at the Wake Forest School of Medicine in North Carolina as well as the head of the Standing Committee on Emerging Infectious Diseases and 21st Century Health Threats at the National Academies of Sciences, Engineering and Medicine.

https://www.nytimes.com/2020/04/20/health/airflow-coronavirus-restaurants.html?searchResultPosition=1

The study itself:
https://wwwnc.cdc.gov/eid/article/26/7/20-0764_article#comment

Seems to me the point of all this is that it's worth looking into, not for the public to be unduly alarmed or final conclusions drawn. It seems likely that this virus--about which we still have so much more to learn--will result in changes and innovations to the HVAC industry. Your attachment on the ionization process was very interesting and hopeful. If all this results in improvements in ionization and filtering, then good for HVAC.

Some local HVAC companies near me are clearly advertising their new Covid protocols for maintaining safety for their workers and customers. All good.

Jamie Hall

If one is interested in a dystopian science fiction story about where we may be heading with all this, may I suggest J-Line to Nowhere, a short story by Zenna Henderson. Problem is, it's darned near impossible to find a copy. It is included in her collection "Holding Wonder", if you can find that...

Zman

@D107
Thanks for the clarification and links. Lots to learn on this one...

D107

@Jamie Hall Ha, as far as my wife and I know, we've been living in a dystopian science fiction movie since early March. Just trying to get back to earth...Of all the events I've lived through--Cuban Missile Crisis, various assassinations, 911, this seems like potentially the most game-changing. I catch myself walking to the supermarket with my mask on and shake my head in disbelief. But my generation has never had to go through a WWII, so hopefully we can all work together half as well as did my father's generation....

unclejohn

I was talking at a illegal gathering about that article to my brother in law and told him it's the start of outlawing air conditioning. He did not think so. I still do. After all it's for our on good and if it just saves one life.

Jamie Hall

At the risk of being a bit harsh: neither you nor any government can save a person's life. You may prolong their stay here on earth for a time; that would be correct. But you cannot prevent them -- or yourself -- from dying, sooner or later.

And, in my view, if you are not free, you might as well be dead.

Fred

I listened to our Governor's update today and they spoke about the risk of recirculating heating and cooling systems. One of the Scientists, a Dr. Weil said that they are finding that recirculating systems can circulate the coronavirus and that that can be mitigated with better Hepa filters, in some cases multiple filters and in some commercial systems that have the ability to change the percentages of external air, that is blended with internal air, doing so (at a clear cost) would help tremendously. he anticipates the industry will redesign some of their upper end systems, especially in commercial applications.

nibs

I do not remember where I read it, but apparently a certain type of LED emitter does a color of Ultra Violet that is very good / or bad if you are a virus, at killing the bug.
Here is a link to a scientific paper
https://www.mdpi.com/2073-4441/11/9/1894

Dave0176

Most MERV 7-8 pleated filters will probably be adequate enough especially once it starts to get dust on it. I find it very hard to see Covid infected droplets making through the entire system including the filters then through a centrifugal fan and in most large commercial establishments the duct work is insulation lined. Your gonna get sick breathing infected droplets from someone coughing or sneezing near you.

That being said I will wear a mask and gloves when changing filters, although I did have Covid19 so I’d imagine I have some sort of immunity but I’ll still wear that stuff.

unclejohn

@Jamie Hall I was being sarcastic.
https://www.youtube.com/watch?v=txQl_JditbI&list=PLZz0442X24dbdmdyqmJDxftq95GsoROEv&index=4
Like in Small Time Crooks.

SlamDunk

Jamie Hall said:

At the risk of being a bit harsh: neither you nor any government can save a person's life. You may prolong their stay here on earth for a time; that would be correct. But you cannot prevent them -- or yourself -- from dying, sooner or later.

And, in my view, if you are not free, you might as well be dead.

I prefer to die young -as late in life as possible.

Jamie Hall

Missed the joke, @unclejohn -- but then my sense of humour isn't what it might be. Sorry!

And @SlamDunk -- the whole thing is a very interesting -- and difficult -- set of tradeoffs. Each of us, individually, has to decide for themselves what amount of government control of their actions they are willing to trade for safety (although at some point the government becomes strong enough to eliminate the possibility of choice), or at least the illusion of safety. Much too complex and difficult for a web discussion! But one can find examples from almost the complete spectrum of choices somewhere in the world today -- with China and the US sort of at opposite ends, and most of Europe somewhere in between. Worth studying...

SlamDunk

@Jamie Hall

It is certainly interesting. And it is absolutely difficult for people who can't afford missing a dozen paychecks or losing their jobs altogether.

But if you think this sucks now, you're going to hate it if we have to go thru this a second time or prolong this even longer just because a handful of people misconstrued a temporary, major inconvenience for a trampling of their rights.

We will see how it goes for Florida, Georgia and South Carolina. I hope they succeed in opening up for business and not prove to be the canaries in the coal mine because I desperately need a hair cut!

Jamie Hall

Seems to me that this thread has gotten away from science -- never mind HVAC -- into a rather fundamental political discussion. I'll be happy to correspond by PM with anyone on the subject (in a civil manner!) -- but not, I think, on The Wall!

unclejohn

I vote beer summit. No mask's, pizza and wings until we figure it out. You can get as close as anyone will let ya.

motoguy128

pecmsg said:

nibs said:

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Care to pick the Pick 6 at Gulfstream Park tomorrow......……….You've got a better chance.

Just saw this. Had to laugh since it’s a reference to a Track with Greyhound Racing. Not sure if you reference horse or dogs racing. We have two retired racers in our home. One of them I think raced at Gulf for a little while.

Although if we were betting which of my dogs will chase down and catch the next squirrel in my back yard, it’s easier to predict.