COVID-19 Emergency - Using UV Lamps to sanitize Face Masks overnight

[not1xor1]

Hi all forum.
I’m Steve writing from Milan in the north of Italy where the Covid-19 emergency is by far the most significant here than in other parts of Italy.

As you may know (what happens in all Europe) we have a shortage in the supply of the non-reusable FFP3 face masks and the ones only available are used and reused for days even more than the datasheet suggests.
Here doctors are even forced to work using simple tissue dentist masks.
Having a wife that is a doctor I am wondering if using technology I could avoid in some ways the danger of reusing the same mask over and over maybe touching her face with a contaminated mask.

both ethanol and isopropanol have been proven to kill the virus in 30 seconds (use pubmed or other reliable search engine to find scientific literature)

unlike ethanol, denaturated isopropanol doesn't stink and doesn't stain and in few hours evaporates completely (I tested that on my FFP3 mask)

isopropanol is widely used in hospitals but you can still find it easily on the web
Just yesterday I ordered another 5 liters supply from http://www.antichitabelsito.it/alcool_isopropilico.htm

so put isopropanol in one of those fridge boxes with airtight lid (PP or glass - doesn't matter) and leave the mask inside for a few minutes, than take it off, close the lid to reuse the solvent other times, and let the mask dry while you sleep.

[hendorog]

Since this is an electronic forum - what about RF at a resonant frequency which destroys the virus?

I found this article where about 60GHz was effective for their sample, but its a bit old.
https://www.livescience.com/7472-kill-viruses-shake-death.html

[PartialDischarge]

I personally find the UV light idea appropiate and easily doable given the small size and certain transparency in the filter material

https://youtu.be/SqytOuYfsnA

[Buriedcode]

I'm not sure I've seen it mentioned here, but 70% isopropyl alcohol (rubbing alcohol) is more effective at disinfection than 80%+.  Although I vaguely remember this being the case for bacteria, unsure about viruses.

[Mechatrommer]

i find its funny when somebody or WHO? suggested that UV lamp should not be around bare skin. people go to beach to get sun tan. baby will get uv lamp treatment if found jaundice (or what?) darker people (which indicates more exposure to UV) are usually much resilient and stronger. and just yesterday, i fixed our front gate due to broken retainer by welding it again and now i have skin rash, tomorrow i expect some dead skin peeling off.. for countless number of time already... free sterilization in the process i guess, and new skin too.. my uv lamp (nail polish curer) that i used to cure solder mask or the uv lamp used in hospitals are nothing compared to that weld arc...

[viperidae]

I'm not sure I've seen it mentioned here, but 70% isopropyl alcohol (rubbing alcohol) is more effective at disinfection than 80%+.  Although I vaguely remember this being the case for bacteria, unsure about viruses.

I heard it has something to do with the combination of water and alcohol that helps dissolve it. I think Dave said it on his recent hand sanitizer video

[Buriedcode]

i find its funny when somebody or WHO? suggested that UV lamp should not be around bare skin. people go to beach to get sun tan. baby will get uv lamp treatment if found jaundice (or what?) darker people (which indicates more exposure to UV) are usually much resilient and stronger. and just yesterday, i fixed our front gate due to broken retainer by welding it again and now i have skin rash, tomorrow i expect some dead skin peeling off.. for countless number of time already... free sterilization in the process i guess, and new skin too.. my uv lamp (nail polish curer) that i used to cure solder mask or the uv lamp used in hospitals are nothing compared to that weld arc...

I'm not sure what your point is but chronic over exposure to UV is a definite cancer risk.  Acute UV burns have ionization damage.  Regular UV burns are not just "oh well, it just toughens me up" - you are putting yourself at necessary risk.

Also you are confusing multiple UV sources with different bands and intensities.  The sun, isn't quite the same as welding flash, isn't the same as UV sterilization lamps.  These have different spectrums, intensities, and the shorter waves don't go far in air.  The UV used to "cure" epoxy glue was likely 395-405nm at low intensity.  That is a far cry from the ~200nm germicidal lamps (that are also a couple of orders of magnitude more intense).

Theraputic UV for skin conditions is carefully controlled, and won't be the short-wave type.  You're effectively saying "this is light, and light is good right?".

[LaserSteve]

    If the bulb is germicidal, mercury filled,  with the clear fused silica envelope and not the  black light blue, it radiates 254 nm. It possibly has a modest but energetic  line near 185 nm depending on doping in the quartz,  and will create localized ozone in some small amount . I spent years working in a polymer fiber lab, making biofibers, and I assure you that all three do a nice job on surface virus and bacteria, given enough time.  We would have used the lamp to sterilize thin layers as they go down, not the finished product.

The UV won't make it through to the core of the mask, but it will help break down most of the things that cause breath odors.

UVA, not so useful, UVB and UVC, will help.

A few one hour exposures will not harm the polymers very much, after all, one of the tests for the mask design  should be degradation in sun light. 

I cant endorse reusing masks, but for most polymer and natural  fibers not a problem for a few modest  irradiations.  The afore mentioned quick splash of 66 to 70% alcohol will do far  better for you, but the UV will also break down many of the organics that cause odors.

Any other solvent is a bad idea given that some fibrous materials are made with a solution deposition process. You do not want to remove any polymer binders that hold the fiber together. 

Good filters are designed to collect pollutants not just at the surface, but to down to a certain depth of the filter material. Hence the reason I state UV helps, but it is not a cure.

My theory is anything is better then nothing, but you must have the right lamp. The lamp you want will quickly give you conjunctivitis, so you need an enclosure or polycarbonate goggles to protect your eyes. Nor do you want to breath in ozone.

If the virus is in a dried organic solution, it might  take a very, very long time to kill the virus. 
Better then nothing, but no where near 100% effective.

Remember, the surgical mask is designed to stop big droplets. Usually it is to prevent the wearer from infecting  others, not to protect the wearer from airborne materials.

Steve

[Mechatrommer]

You're effectively saying "this is light, and light is good right?".

i dont say we can keep exposed to UV all day long. i'm trying to say, its not that bad as its said. i usually find people who get rid of the said item entirely because of some warning from authority. people dont get into electronics because afraid of lead poisoning. who got mad or lost temper control due to life long soldering? people dont buy items from china or quarantine their arrived parcel for few days (after few days already in shipping) because extra fear to virus. people dont get into electronics afraid of get killed by mains elecricity. and many more examples i cant point them all now. the point is, these warning, without adequetely educate people on what kind of risk, made people extra taboo. UV probably can make skin cancer, but for how long exposure? 1 day? 10 days? or 1 year continuos exposure? most people will think 1 hour exposure (or even less like 1 minute exposure) and you'll get cancer. this people dont know we walked everyday under the sun without getting anything bad or short lived, we may get some benefit as well, sun produces all kind of spectrums. but i dont say we should lay under the sun all day long for no reason, just do what we have to do for our benefit, no need to raise extra taboo or fear.

[KaneTW]

UVC is not something you should willingly expose yourself to, ever. It causes cataracts and skin damage at the intensities required to kill germs.

There's research indicating that 210nm UVC is safe, but a) I'm skeptical and b) 210nm lamps are quite expensive.

254nm UV (main mercury line) will damage you.


I'm worried about the material compatibility of FFP3/etc masks to solvents. UV definitely won't cut it for sanitizing them.

[Bud]

So heat then appears to be the safest method both in terms of coverage and not damaging the material.

[Zero999]

You're effectively saying "this is light, and light is good right?".

i dont say we can keep exposed to UV all day long. i'm trying to say, its not that bad as its said. i usually find people who get rid of the said item entirely because of some warning from authority. people dont get into electronics because afraid of lead poisoning. who got mad or lost temper control due to life long soldering? people dont buy items from china or quarantine their arrived parcel for few days (after few days already in shipping) because extra fear to virus. people dont get into electronics afraid of get killed by mains elecricity. and many more examples i cant point them all now. the point is, these warning, without adequetely educate people on what kind of risk, made people extra taboo. UV probably can make skin cancer, but for how long exposure? 1 day? 10 days? or 1 year continuos exposure? most people will think 1 hour exposure (or even less like 1 minute exposure) and you'll get cancer. this people dont know we walked everyday under the sun without getting anything bad or short lived, we may get some benefit as well, sun produces all kind of spectrums. but i dont say we should lay under the sun all day long for no reason, just do what we have to do for our benefit, no need to raise extra taboo or fear.

You've completely missed the point. UV is a broad spectrum of electromagnetic radiation from 400nm, all the way down to 10nm. The 253.7nm radiation produced by germicidal lamps is not something any human is exposed to during their everyday life, because it is completely absorbed by the earth's atmosphere. Human skin has no defence against it, (darker skin is just as vulnerable as lighter skin) which is why one needs to be very careful not to expose themselves to radiation from a germicidal lamp.
https://en.wikipedia.org/wiki/Ultraviolet

[Mechatrommer]

weld arc covers whats absorbed by the ozone very well (200 to 400 nm)... https://www.ccohs.ca/oshanswers/safety_haz/welding/eyes.html i'm one of many living souls to tell the tale... and if its real hazard devices (germicidal lamp), you wont be able to get it off the shelf anyway... what i saw on sales are for kitchen, bathroom etc where the vulnerable SWMBO usually at...

[Zero999]

weld arc covers whats absorbed by the ozone very well (200 to 400 nm)... https://www.ccohs.ca/oshanswers/safety_haz/welding/eyes.html i'm one of many living souls to tell the tale...

A welding mask is essential and it wouldn't surprise me if a germicidal lamp emits more UVC, than a welding arc. It's certainly on for longer, so would result in a higher exposure.

and if its real hazard devices (germicidal lamp), you wont be able to get it off the shelf anyway... what i saw on sales are for kitchen, bathroom etc where the vulnerable SWMBO usually at...

What are you talking about? Hazardous items such as knives and  bottled gas are widely available, as are germicidal lamps.

[Mechatrommer]

knives and bottle gas can be controlled and contained, hazardous lamp cant, much like nuclear radiation. and its not like we are going to put our skin 1cm from radiation at any moment. the fact that it is sold means its not as hazardous as its said in the warning. its similar to when authority gives warning "dont go outside you'll get caught by covid" so what do we do? ask our nurse/doctor wife to go home? some people will take this literally.

[Zero999]

knives and bottle gas can be controlled and contained, hazardous lamp cant, much like nuclear radiation. and its not like we are going to put our skin 1cm from radiation at any moment. the fact that it is sold means its not as hazardous as its said in the warning. its similar to when authority gives warning "dont go outside you'll get caught by covid" so what do we do? ask our nurse/doctor wife to go home? some people will take this literally.

What have you been smoking?

Germicidal lamps have to have safety warnings printed on them, because they are hazardous, but not as much has nuclear radiation. The UVC emission ceases, as soon as the lamp is switched off. The radiation can cause severe skin burns and eye damage, but is easily blocked by most clothing, wood, plastics and glass.

Fortunately, it's not too difficult to mitigate the hazard from a germicidal lamp. Operate it a box or cupboard, with adequate seals to prevent the radiation from escaping and fit any doors with safety interlock switches to turn the lamp off, before the door opens enough to allow the radiation to escape.

[KaneTW]

I'm buying UVC lamps every year for my pond. Many HVAC systems have them. They're off-the-shelf unrestricted items.

[Bud]

Interesting study on survival of the virus on different type of surface materials

https://www.nejm.org/doi/full/10.1056/NEJMc2004973

Copper 4 hrs
Cardboard 24 hrs
Stainless steel 48 hrs
Plastic 72 hrs

I wonder what is the magic with copper....

[SiliconWizard]

https://en.wikipedia.org/wiki/Antimicrobial_properties_of_copper

[Stray Electron]

weld arc covers whats absorbed by the ozone very well (200 to 400 nm)... https://www.ccohs.ca/oshanswers/safety_haz/welding/eyes.html i'm one of many living souls to tell the tale... and if its real hazard devices (germicidal lamp), you wont be able to get it off the shelf anyway...

   Wrong.  The old EPROM erasers all used germicidal UV lamps. I've pulled the bulbs out of over a dozen of them and they're all marked as germicidal lamps, and have quartz tubes and contain visible amounts of mercury.

    Previous posters are correct, these are definitely not eye-safe and the erasers all have interlocks to prevent them from being operated when the drawers are open, but you can take the tubes out and use them in a standard florescent fixture. I haven't looked in some years but the catalogs from the larger lamp companies used to all list germicidal lamps.

[Gyro]

Interesting study on survival of the virus on different type of surface materials

https://www.nejm.org/doi/full/10.1056/NEJMc2004973

Copper 4 hrs
Cardboard 24 hrs
Stainless steel 48 hrs
Plastic 72 hrs

I wonder what is the magic with copper....

https://en.wikipedia.org/wiki/Antimicrobial_properties_of_copper

Yes, the antimicrobial properties of copper, and other metals like Silver have long been known. Brass door handles and door plates were very effective in public buildings and hospitals. Unfortunately these days, everything has gone over to anodized Aluminium which, I think, is pretty much inert.

The same with the traditional use of Linoleum flooring, which has natural and lasting antimicrobial properties.

[james_s]

i find its funny when somebody or WHO? suggested that UV lamp should not be around bare skin. people go to beach to get sun tan. baby will get uv lamp treatment if found jaundice (or what?) darker people (which indicates more exposure to UV) are usually much resilient and stronger. and just yesterday, i fixed our front gate due to broken retainer by welding it again and now i have skin rash, tomorrow i expect some dead skin peeling off.. for countless number of time already... free sterilization in the process i guess, and new skin too.. my uv lamp (nail polish curer) that i used to cure solder mask or the uv lamp used in hospitals are nothing compared to that weld arc...

"UV" covers a broad range of wavelengths from just below the human visual threshold down into deep UV which are high energy photons, genuine ionizing radiation. Xrays/gamma rays are just photons, even higher energy than what is typically considered light. I do think it's a bit silly the amount of fear that the word "radiation" stirs and yet people deliberately go sit out in the tropical sun to irradiate their skin. Some is tolerable of course but UV exposure absolutely causes skin cancer at some levels and like any type of ionizing radiation there is no threshold known to be absolutely safe. Just look at what it does to many plastics and other materials. Leave them out in the sun for a while and they crumble to dust, pigments fade rapidly, the high energy photons blast apart molecular bonds.

[james_s]

knives and bottle gas can be controlled and contained, hazardous lamp cant, much like nuclear radiation. and its not like we are going to put our skin 1cm from radiation at any moment. the fact that it is sold means its not as hazardous as its said in the warning. its similar to when authority gives warning "dont go outside you'll get caught by covid" so what do we do? ask our nurse/doctor wife to go home? some people will take this literally.

Maybe things are done differently where you are but I would never expect something to be safe just because it is sold to the general public. Here I can walk into Walmart and buy a jug of hydrochloric acid, a bottle of MEK, a propane soldering torch and fuel, a hunting knife, a crossbow and bolts, insect poison, a box of shotgun shells and any number of other things including a germicidal UV lamp, no restrictions at all aside from showing ID to prove that I'm at least 18 years old to buy the weapons.

The UV lamps have a warning on the box to avoid exposure to eyes and skin. Sure it won't hurt you to look at one for a few seconds but I wouldn't recommend making a habit of it, expose your skin to one for a half hour and you'll get a UV burn for sure. I've had the same thing happen arc welding where I had a patch of exposed skin somewhere and got a sunburn from the arc. The world is full of dangerous things, don't expect someone else to protect you from everything, that attitude is a cancer on society which has led to ridiculous warning labels plastered all over everything and far too many things people are not even allowed to do because someone is afraid of being sued.

[not1xor1]

Remember, the surgical mask is designed to stop big droplets. Usually it is to prevent the wearer from infecting  others, not to protect the wearer from airborne materials.

I'm Italian like the original poster, it is just a matter of misunderstanding or if you prefer a translation error. Here we usually call mask a different kind of device made with thick fabric. It completely covers mouth and nose leaving no gap and is so thick the virus can't get through... here are some pictures (sorry it is in Italian)

BTW I apologize to everybody for my rude comment of yesterday

[LaserSteve]

Don't Laugh,  My supervisor just sent a partial box and our last unopen box of N95 to the local hospital.  At the emergent  request of a  surgeon alumni.  I'm in the Midwest USA.
That was our "Stash" for our critical personnel.

Steve