(Coronavirus) On UV Sanitization

[linux-works]

I know its not meant for uvc; that's part of why I wanted it. take the reading from an A meter, then from the same light take the C reading. the bands are overlapping a bit and the gains are not the same but it can give an idea of which 'side' the lamp under test is peaking at. it won't be both, so I'd expect a bigger than normal reading on one side or the other.

the only diff I can see between the general A meter and its more expensive C meter is the probe, and that might be hackable by using some other cheaper C probe (diy or otherwise) into that meter.

 

[linux-works]

from the hackaday article, the vendor's own test report!

its criminal to be selling these, when the sellers had the actual *data* and they either ignored it or simply were too dumb to understand it.

I know, buyer beware, but wow, is it really a world we want to live in, when any yahoo can sell things that will endanger your lives?

some occupations need testing and have qualifications. why does 'sales' always get a free pass, in that you can be the dumbest person on earth and still be a 'successful' salesman?

sorry for the rant. just that the stakes are high, on some items you buy, and maybe for some things, you *should* need a license. its why the concept of license exists; to protect people.

 

[joetomasone]

got my meter today!

here's the datalog output; the meter logs to sdcard; I then copy the .xls file to my pc, run a spreadsheet prog on it and you can see where the left data set shows uvc data (I set the datalogger, left the room, used an RF remote to trigger the bulb, let it run a while, then turned it off).

View attachment 535103

BTW, the normal recommendation for SARS-CoV (NOT CoV-2, for which there don't seem to be any recommendations yet) is that 200 mJ/cm2 is required for SAL 99; so the legit bulb you measured will take some time to work.

 

[linux-works]

wonder if a parabolic dish might work.

be right back...

ok, I'm back. worth noting: do not look at light from parabolic dish with remaining eye.

 

[linux-works]

BTW, the normal recommendation for SARS-CoV (NOT CoV-2, for which there don't seem to be any recommendations yet) is that 200 mJ/cm2 is required for SAL 99; so the legit bulb you measured will take some time to work.

so, 'turn it on until it smells like pork' is not quite scientific enough?

yeah, we can measure things; but that's still not true feedback that the whole process is 'good'.

I'll probably over-blast things just because its too hard to actually know how much is enough.

 

[joetomasone]

so, 'turn it on until it smells like pork' is not quite scientific enough?

yeah, we can measure things; but that's still not true feedback that the whole process is 'good'.

I'll probably over-blast things just because its too hard to actually know how much is enough.

By the time we get more valid info than the stuff they presented in tonight's "briefing", this will all be over, I think. However, they seem to indicate that sunlight helps invalidate -CoV-2, which would likely mean that it is less hardy than -CoV.

I generally go quite overboard with my UVC (and ozone) dosage, because it doesn't take any more effort on my part.

 

[Alan Kk]

BTW, the normal recommendation for SARS-CoV (NOT CoV-2, for which there don't seem to be any recommendations yet) is that 200 mJ/cm2 is required for SAL 99; so the legit bulb you measured will take some time to work.

What does SAL 99 mean? I have been reading that 6.4 mJ/cm2 is needed to kill 99% of ssRNA viruses. That's the type Covid is.

 

[joetomasone]

What does SAL 99 mean? I have been reading that 6.4 mJ/cm2 is needed to kill 99% of ssRNA viruses. That's the type Covid is.

Sorry - Sterility Assurance Level. Frankly, I've seen figures all over the place - the figure quoted varies depending on which virus is being quoted (all ssRNAs, MERS, SARS-CoV, etc, the medium to be disinfected (surface vs. N95 mask, etc) AND the particle medium (saliva, water, blood, protein, etc). The 200 mJ/cm2 figure was twice the SAL 95 level for SARS-CoV on a cardboard surface - which should be good for the stuff I am disinfecting - packages, mail, and the like. Masks seem to require higher fluence (1 J/cm2 is the most often cited figure, but again, not for SARS-CoV-2 - usually SARS-CoV). This was based on the curvature of the mask introducing shadowing and the fact that the test environments were exclusively direct radiation on two axis in a room - not in an enclosed reflective environment, for example.

So really, it depends on what you are disinfecting. For my needs, a reflective closed environment using a 35W 185/254 nm blub (to produce UV-C and ozone) for a minimum of 15 minutes seems to work adequately even without factoring in the half-life and humidity figures proffered yesterday. If SARS-CoV-2 is less hardy than SARS-CoV, then using figures for the latter (and thereby inducing overkill for SAL 99) seems like a reasonable approach. The ozone is just the icing on the cake - and should work well for masks.

 

[Big Earl]

So, I finally finished the build of my UV-C disinfecting box. Here's some images and details.

Parts and tools needed:

1. Igloo ice chest
2. UV-C bulb (https://www.amazon.com/gp/product/B085JPG789/ref=ask_ql_qh_dp_hza?th=1)
3. Aluminum foil
4. Hot glue gun and glue sticks
5. Closet door guides (Prime-Line Tan Bypass Closet Door Guide-N 7527 - The Home Depot or similar)

I lined the sides, bottom, and top of the ice chest with aluminum foil which was glued on with the hot glue.The closet guides were drilled into the bottom to act at standoffs for packages and mail to hold them upright and off the bottom of the box (so the bottom can be disinfected as well)I then drilled holes in the side of the cooler and filed it to make a space for the bulb to be inserted from the outside. Once the bulb was inserted, I screwed the bulb housing to the cooler side to keep it in place.Then I mounted the ballast/electronics box to the bulb and secured it in place with screws as well.


Overall view of box:

View attachment 533448


Closeup of inside with bulb (on right) and standoffs.

View attachment 533449


Showing 18 mw/cm2 with sensor on top of the bulb. I tend to get around 10 mw/cm2 on the leading edge of a package occupying about 3/5 of the volume of the box, and about .15 to ..20 on the furthest point on the shadow side of the box (via reflection).

View attachment 533450


The electronics/light mount on the outside of the box.

View attachment 533451


Closeup of the standoffs.

View attachment 533452

Nice build! The same light got delivered to me today. I have a couple of spare coolers kicking around, so I’ll rig something up this weekend.

 

[eevee-fan]

Case: ebay seller who's account got deactivated. Notified eBay that item is not as described. A few days later, seller emailed to give a discount for the scam corn LED bulb. Notified eBay that resolution is unacceptable. A few days later, seller emailed back to allow return and will send shipping label. Waiting on shipping label... Guess seller wants the bulbs back to either return to wholesaler or to scam another buyer.

 

[joetomasone]

Nice build! The same light got delivered to me today. I have a couple of spare coolers kicking around, so I’ll rig something up this weekend.

I have two 60W on the way and plan to make V2.0 out of a footlocker for more capacity.

 

[linux-works]

Case: ebay seller who's account got deactivated. Notified eBay that item is not as described. A few days later, seller emailed to give a discount for the scam corn LED bulb. Notified eBay that resolution is unacceptable. A few days later, seller emailed back to allow return and will send shipping label. Waiting on shipping label... Guess seller wants the bulbs back to either return to wholesaler or to scam another buyer.

wow, that's too bad. bet he wants to resell it and maybe cause harm to another person.

I stopped using ebay entirely. I don't love paying 'prime membership' but I have to admit, amazon always comes thru for me, as a customer. both amazon and ebay can be bad, but if you are 'prime' there is actual oversight if you call and get a real person on the phone. they would not force me to return junk that was likely to cause a person harm.

 

[linux-works]

I finally got around to removing the uv-a sensor from the adafruit board and installed the digikey uv-c sensor.

works fine. shows a good value when I put it near a real uvc bulb.

note, for a uvc 'detector' you don't need the special c sensor. the easily buyable a-sensors will still work down in the c band (or is that 'up' in the c band) and if you just want to know if the light is still on while your box is closed for the duration of the run, the uva sensors are good enough.

I plan to make a portable uvc bluetooth sensor/meter pair and try to calibrate it close to my commercially bought meter. for that, I did want to remove the original A and put the new C in.

surface mount removal and install was not hard, but it was tricky and I didn't do the best job. it works but won't win any prices for neatness

original on left, uvc-upgrade sensor on right. no, I didn't clean the flux off yet, lol.

and the black line you see on the uvc sensor - its not a crack or anything; its how it is. below, on the smd pads, its offset like that to show anode/cathode polarity and I guess that shows thru to the top thru the clear quartz (?) casing.

 

[Big Earl]

We got around to building our cooler today. The finishing touch will be a wire rack for the bottom to hold items up.

It produces a lot of ozone. Whatever the UVC radiation doesn’t kill, the ozone surely will.

Super 77 spray adhesive

Aluminum foil and metal duct tape

Ballast and controls mounted on top of the lid

Wires extended so the socket and lamp can be mounted inside the lid.

 

[linux-works]

I still think the rotating turntable idea is worth adding to your cooler.

in fact, I'm now going to try adding a top motor, as well:

https://www.amazon.com/gp/product/B07QTQ4QN9/

if I mount that to the inside top lid and hang a hook or even alligator clip from it, I can have light on the bottom and the top hanging thing will rotate around at a slow rate, hopefully with the light hitting more angles as it sweeps thru rotations.

I'm thinking my box will be modular so I can put lights on the bottom and use the top motor/hook idea; or a metal rack in the middle and lights above and below; or a 3rd config with a rotating motor base (like a microwave oven food rotater) and the lights on top and maybe on the sides.

the fact that I keep changing my mind is what is causing the box to be delayed, though

 

[SwTslaGrl]

Tangent: A startup delivering UVC box for disinfecting escalator handrails,

German start-up in global demand with anti-virus escalators

 

[linux-works]

found an article (by a vendor, so take it fwiw) on a china standard method to read/test/calibrate uvc readings from germicidal lamps:

How to Measure UV Light Intensity of Germicidal Lamps with an UV-C light intensity meter?

if you follow links, here's the doc from china:

WS/T 367-2012 PDF - Auto immediate delivery. (clicking thru gets you a pdf)

section C.6 is where UV starts

not sure this says all that much, but maybe its useful.


btw, I've been looking at what the various vendors of meters (like this) offer, for features, as I plan to add ones that make sense to my own DIY design. mine will be freely available and fully open source for anyone to use, BSD style license. my bluetooth system has been working and building mine will cost nowhere near the $500 range that this vendor is charging for theirs

 

[joetomasone]

I purchased one of the corn cob bulbs on Amazon and after reading this report I requested a refund stating did not emit UVC. The refund was immediately given without a request to return the item indicating the seller acknowledges it was a fake.

If anyone wishes to test it, let me know.

FYI, @dkemme sent me the bulb and I tested it. Here's what I reported to him - reposting it here since I think it will be enlightening to everyone:

The bulb arrived today, and - as we suspected - it's as fake as a $3 bill.

Now, to be fair, it does indeed put out UVC - but it's totally incidental to the visible light output and is at such a low dosage (.007 mW/cm2) that it would take 7.93 hours to reach the minimum 200 mJ/cm2 considered the most reasonable safe dosage to inactivate 100% of virus particles. Even to get to SAL95 would take over 4 hours - and these figures assume that you are touching the lamp to the surface as I took the measurement with the UVC probe right up to the LEDs. Factor in the inverse square law and it's putting out basically zero - so low the meter can't register it - once you get a few cm away.

For comparison, here are the figures for some other UVC products I have here:

Homedics portable phone sterilizer LEDs - two come in the product - each puts out 1.5 mW/cm2
Chinese cell phone sterilizer from Amazon - two UVC tubes - each puts out 0.4 mW/cm2
My 35W bulb that I used in my project - 18 mW/cm2

In sourcing the UVC LEDs, it appears that even in bulk they are at least $2.00 each - so your bulb, with 347 LEDs on it (I counted!) should be easily a few hundred bucks. Even if it was an $80 bulb, the LED cost would have to be around 20 cents each. And - of course - they don't look like UVC LEDs which have a distinctive casing, as seen here:

E275-60-STRIP

I'm planning on writing a blog article about UVC disinfection, and will include this bulb as an example of what NOT to buy.

Incidentally, for laughs and giggles I checked it with a UVA/UVB meter and there was zero there as well - so the bulb is emitting zero UV light at all. It's just a pale blue/white visible light bulb.

 

[joetomasone]

Fake as hell corn bulb #2 arrived today... Short story even shorter, it's UVA - a blacklight.





Just as an example for how fake these corn bulbs are in pretty much every respect, I Googled the part number from the bulb and besides the myriad sites selling it as germicidal, one actually is selling it as a normal light bulb....

VeraLED NS-ACL LED Corn Lamp E26 2500-7000K Replaces 45W-200W Incandescent Lamp

On top of that, there are obviously loose components inside - it rattles!


Refund request issued....

 

[eevee-fan]

Fake as hell corn bulb #2 arrived today... Short story even shorter, it's UVA - a blacklight.

View attachment 538790

Just as an example for how fake these corn bulbs are in pretty much every respect, I Googled the part number from the bulb and besides the myriad sites selling it as germicidal, one actually is selling it as a normal light bulb....

VeraLED NS-ACL LED Corn Lamp E26 2500-7000K Replaces 45W-200W Incandescent Lamp

On top of that, there are obviously loose components inside - it rattles!

Refund request issued....

So you can make a suntan bed out of it?