Fear and Loathing, a Rat Flu Odyssey

[jono]

Wouldn't you want intake to be high and outtake to be low? So aerosols were dropped to floor level then expelled? Like basically make the room a big fume hood but going in the opposite direction.

That argument has been made for changing airplanes around, too, but it's a double-edged sword: drawing air up from the ground goes the same way as the natural air currents around the people, but if your most contaminated surface is the floor you're drawing that air up past their faces. Probably still better, just maybe not by a lot? Seems ideally you'd evacuate from both floor and ceiling, but everyone in the room needs a source in that case so you don't flow straight around at face level. The line between better than nothing and pretty impractical comes on fast.

[Casey E]

An article on ventilation and what we know, which isn't a whole lot, but

When windows cannot be opened, classrooms could run portable HEPA filters, which are capable of trapping viruses this small, and which sell for as little as a few hundred dollars. Marr advises schools to measure airflow rates in each classroom, upgrade filters in the HVAC system to MERV 13 or higher (these are air filter grades), and aspire to meet or exceed ASHRAE (the professional society that provides HVAC guidance and standards) standards.

https://www.theatlantic.com/health/a...1CJKTEW-0dZKVw

[glademaster]

Many schools in the US are so old they don't have ducted HVAC systems.

[summit]

We've used simple HEPA filtered fans to scrub air in clinic exam rooms inbetween patients.

Many commercial building central air systems have return ducts that recirculate, including doctors offices.

[::: :::]

i have a contractor friend who just installed a UV filter in their a/c

[jono]

Incompetence, chaos, and confusion; the hits just keep coming.
How Jared Kushner’s Secret Testing Plan “Went Poof Into Thin Air”

I'm trying to find this story in a shorter/less comment-filled form for easier digestion by others. Anybody seen that anywhere? The facts alone seem more powerful than the obvious commentary.

[jono]

i have a contractor friend who just installed a UV filter in their a/c

UVC lights are pretty available if you can live with 254 nm--meaning, don't shine them on the humans. 207-222 nm seems in shorter supply, excepting the fakes on Amazon and Alibaba. But that does appear to be the best answer going forward, as mentioned here:

https://www.nature.com/articles/s41598-020-67211-2

[summit]

UVC lights are pretty available if you can live with 254 nm--meaning, don't shine them on the humans. 207-222 nm seems in shorter supply, excepting the fakes on Amazon and Alibaba. But that does appear to be the best answer going forward, as mentioned here:

https://www.nature.com/articles/s41598-020-67211-2

Mercury vapor is usually 254nm. Seems like the air duct systems it doesn't matter safety-wise, as its contained well away from human eyes.

That study is interesting and seems far UVC is more applicable to aerosol deactivation/air treatment than surface treatment or equipment disinfection?

We have these portable xenon pulse light system "robots" for room disinfection that are "broader" spectrum of 200-315nm. Still don't think you should stare... they have motion sensor safety interupts.

[jono]

Mercury vapor is usually 254nm. Seems like the air duct systems it doesn't matter safety-wise, as its contained well away from human eyes.

That study is interesting and seems far UVC is more applicable to aerosol deactivation/air treatment than surface treatment or equipment disinfection?

We have these portable xenon pulse light system "robots" for room disinfection that are "broader" spectrum of 200-315nm. Still don't think you should stare... they have motion sensor safety interupts.

Polycarbonate ("Uv-excluded) face shields seem like a good idea with the robots.

I need to dig in a little more, but I get the impression that 222 nm was quicker acting. And UVA and UVB not so much. Interesting point about penetration, though, assuming the surface being disinfected isn't just opaque.

[old goat]

The problem with individual room HEPA filters is that someone--presumably a minimum wage custodian--has to change the filters. The filters can be cleaned and reused but that seems like a bad idea, so new filter ? how often? We know that in Covid wards in a hospital the most dangerous place is where people remove their PPE, in the process sending virus into the air. The same thing would likely apply to filter changing, and protecting the custodian will be difficult. Better than doing nothing I suppose.

Anyone who's emptied and cleaned a HEPA filtered shop vac or woodworking dust collection system knows what I'm talking about.

[DBdude]

It's gonna hit Alabama!Attachment 335852

hahahahaha

a classic

[Skidog]

Dont wanna throw shit, but Sweden reports only 4 covid deaths July 31, 322 on July 29. Cases going down.

Sup with that?

[The AD]

Dont wanna throw shit, but Sweden reports only 4 covid deaths July 31, 322 on July 29. Cases going down.

Sup with that?

Keep in mind most Swedes vacation for several weeks during the summer and many of them go to relatively isolated cottages. Social distancing is a way of life for them.

[wooley12]

Nice. Coug. I just bought a doughnut for $.79.

[Core Shot]

Keep in mind most Swedes vacation for several weeks during the summer and many of them go to relatively isolated cottages. Social distancing is a way of life for them.

Swedes social distance year round.

[KQ]

[jono]

The problem with individual room HEPA filters is that someone--presumably a minimum wage custodian--has to change the filters. The filters can be cleaned and reused but that seems like a bad idea, so new filter ? how often? We know that in Covid wards in a hospital the most dangerous place is where people remove their PPE, in the process sending virus into the air. The same thing would likely apply to filter changing, and protecting the custodian will be difficult. Better than doing nothing I suppose.

Anyone who's emptied and cleaned a HEPA filtered shop vac or woodworking dust collection system knows what I'm talking about.

Portable units address most of this. Worst case you just take a unit out of service for a few days before opening it, but I'm sure there's an argument for leaving them on over the weekend and changing them first thing Monday morning. But the filters are not like shop vac filters, which are full of dry dust that never got into the filter. They're mostly capturing these smallest particles deep in the filter, which is pretty thick. Your point stands, though, they should get at least as much respect as the dirtiest hippy that's been in the room.

[TBS]

Heh - I got food poisoning from local takeout two weeks ago. Basic Hamburger with french fries at Takoda's if your Sisters friend cares...

Server staff (college-age kids) were all nose-dicking and removing their masks when at the pickup station. The one exception was the hispanic busperson - she had her mask in place and never touched it in the 10 minutes I waited.

I know this has nothing to do with gastro-intestinal distress, but I'm not going back

[LongShortLong]

they should get at least as much respect as the dirtiest hippy that's been in the room.

ouch, or oof as the kids say

[muted]

Dont wanna throw shit, but Sweden reports only 4 covid deaths July 31, 322 on July 29. Cases going down.

Sup with that?

You could make an effort and google it, read articles, and come to your own conclusion. It's been discussed earlier in this thread too.

[Skidog]

You could make an effort and google it, read articles, and come to your own conclusion. It's been discussed earlier in this thread too.

yeah I know it has and has typically been shut down quickly. this is more up to date info. I have googled...wondered if the collectives thoughts have changed.

[Rideski]

Heh - I got food poisoning from local takeout two weeks ago. Basic Hamburger with french fries at Takoda's if your Sisters friend cares...

Server staff (college-age kids) were all nose-dicking and removing their masks when at the pickup station. The one exception was the hispanic busperson - she had her mask in place and never touched it in the 10 minutes I waited.

I know this has nothing to do with gastro-intestinal distress, but I'm not going back

https://www.newsweek.com/mass-food-p...aurant-1521716

[Benny Profane]

hahahahaha

a classic

Don't laugh. He may try it again.

[summit]

I can't see why one would need to change the filter media on a weekly basis for a room based HEPA.

The industrial units we used to convert hospital rooms haven't had their filters changed since we installed them in February.

Clinic and hospital air have low PM to start with. In room filtering is not ideal, but if you turn the room over a few times it is way better than the nothing that many outpatient settings are doing. (if I have a 800cuft exam room and a 400cfm HEPA unit, and turn it on for 10 minutes, I've nominally removed over 99% of the particulate). Sequester viral particle bearing particulate in the filter media and it is most likely all dead in a few hours.

If your filters aren't clogged, then you get your expected ACH with no breakthrough. No filter changes needed.

I like it more when you blow it out the exhaust though. That's what we do in hospital.

[old goat]

yeah I know it has and has typically been shut down quickly. this is more up to date info. I have googled...wondered if the collectives thoughts have changed.

There is no collective. In the history of this forum at most 2 people have agreed with each other, never 3 or more.