(Coronavirus) On UV Sanitization

[joetomasone]

So you can make a suntan bed out of it?

For a small animal, perhaps.



Refund received within 6 hours... Guess they knew the request was coming? The item is also no longer for sale by that seller. #SmallVictory



You have received a message from the Amazon Seller - Hawks Lighting
Order ID: 112-2443773-8673821

Count Product Name and ASIN
1 2020 Newest 500W Equivalent UV Germicidal Lamp Led UVC Light Bulb E26, Suitable for Home, Warehouse, Supermarket
ASIN: B086GF68Q7
Please keep the item and get the refund


Amazon.com <[email protected]>
6:35 AM (4 hours ago)

to me

Hello,

We're writing to let you know we processed your refund of $52.99 for your Order 112-2443773-8673821 from Hawks Lighting.

This refund is for the following item(s):

Item: 2020 Newest 500W Equivalent UV Germicidal Lamp Led UVC Light Bulb E26, Suitable for Home, Warehouse, Supermarket
Quantity: 1
ASIN: B086GF68Q7
Reason for refund: Customer return

Here's the breakdown of your refund for this item:

Item Refund: $52.99

 

[linux-works]

For a small animal, perhaps.

... "pop!" goes the weasel!

 

[joetomasone]

My two 60w UVC lights arrived today.. So powerful my meter can't measure it! (Tops out at 20 mW/cm2). Some back of the napkin math tells me that it should work out to around 28 mW/cm2. "Big Box" gets under construction tomorrow!

 

[Big Earl]

My two 60w UVC lights arrived today.. So powerful my meter can't measure it! (Tops out at 20 mW/cm2). Some back of the napkin math tells me that it should work out to around 28 mW/cm2. "Big Box" gets under construction tomorrow!

How long is your required dwell time at that output for effective sterilization? Are your UVC lamps also ozone-generating?

 

[joetomasone]

How long is your required dwell time at that output for effective sterilization? Are your UVC lamps also ozone-generating?

Have to test the fluence at various points in the box once both lights are installed. I aim for 200 mJ/cn2 - which is overkill, but I like overkill where this is concerned, especially since I have seen figures all over the map. 100 mJ/cm2 seems to be the figure most often cited to take care of all pathogens, so I figure a double dose eliminates any ambiguity.

That being said, I expect that the default 15 minute timer will be more than sufficient. I'll post more once I've gotten it built and tested.

 

[DavidB]

… I like overkill where this is concerned, especially since I have seen figures all over the map.…

The two drawbacks with overkill are (1) energy wasted (a minor issue), and (2) degradation of the objects being sterilized. Since masks are in short supply, I wouldn't want to unnecessarily shorten their usable life.

 

[Big Earl]

Have to test the fluence at various points in the box once both lights are installed. I aim for 200 mJ/cn2 - which is overkill, but I like overkill where this is concerned, especially since I have seen figures all over the map. 100 mJ/cm2 seems to be the figure most often cited to take care of all pathogens, so I figure a double dose eliminates any ambiguity.

That being said, I expect that the default 15 minute timer will be more than sufficient. I'll post more once I've gotten it built and tested.

I suspect 15 minutes will be well in excess of what's necessary. My goal is short cycles so that I can rapidly process/disinfect groceries. A typical bi-weekly grocery run requires about 10 rounds of sanitizing in my UVC cooler to cover everything, so 15 minute cycles would take quite a while.

 

[linux-works]

took a lot of time but my shipment came in today, too 6 weeks or so.

crappy image. who cares

I bought these from amazon, but slowboat from china (around $20 ea instead of 2x or 3x that). I did buy some at the local amazon price and they came with yellow warning stickers on them, branded/labeled uvc bulbs and end-caps installed. these have no name on the bulb at all, no warnings (except on the bottom, where they get mounted, lol). you have to install the end cap from the baggie. oh, and these seem to be daisychainable, and there is a male-male extender that lets you plug these into each other, end to end. I might have 2 in a box and on different sides, so I'll need to wire up a jumper or extender of some kind. they give you lots of cheap cords with switches but those are going into the trash; I bought UL rated white cords separately (my experience is that 'copper' cords from china are less and less copper and more and more 'copper clad aluminum' and I just don't believe in that crap. not at all.)

hope these don't do bad things. well, badder than they are supposed to.

 

[linux-works]

I'm wondering if we can get hospitals to help us 'certify' our builds.

think about that. if we could know that, when we placed that baddie inside, pressed the button for X time and had their lab test the result, we'd know. its crazy to guess. we have to right now, but we should not have to, long term.

I wonder how best to approach a place that would have the ability to help get some kind of baseline established, even if its for a common standardized design (box size, lamp output, etc). we just need to be in the ballpark and with a padding factor.

right now, its total guesswork.

 

[joetomasone]

I'm wondering if we can get hospitals to help us 'certify' our builds.

think about that. if we could know that, when we placed that baddie inside, pressed the button for X time and had their lab test the result, we'd know. its crazy to guess. we have to right now, but we should not have to, long term.

I wonder how best to approach a place that would have the ability to help get some kind of baseline established, even if its for a common standardized design (box size, lamp output, etc). we just need to be in the ballpark and with a padding factor.

right now, its total guesswork.

You'd need a lab, not a hospital.

You *can* do a basic test at home - get a kit with petri dishes and agar, swab under your toilet bowl rim and contaminate two agar-lined dishes. Put one in your box, leave the other one as a control. Check them in 48h.


On a separate topic, the larger ice chest I was going to use for Big Box is unsuitable. Anyone have any ideas besides ice chests for a big box that isn't flimsy like cardboard and not as heavy as building it from wood?

 

[linux-works]

https://www.amazon.com/gp/product/B06ZZNLLP5

$35 for 2 of them. black, so no light gets thru, cheap enough and you get 2 tries if you screw it up

 

[deonb]

Have to test the fluence at various points in the box once both lights are installed. I aim for 200 mJ/cn2 - which is overkill, but I like overkill where this is concerned, especially since I have seen figures all over the map. 100 mJ/cm2 seems to be the figure most often cited to take care of all pathogens, so I figure a double dose eliminates any ambiguity.

That being said, I expect that the default 15 minute timer will be more than sufficient. I'll post more once I've gotten it built and tested.

How do you calculate mJ/cm2 from mW/cm2? Just multiply by number of seconds?

 

[linux-works]

I suspect 15 minutes will be well in excess of what's necessary. My goal is short cycles so that I can rapidly process/disinfect groceries. A typical bi-weekly grocery run requires about 10 rounds of sanitizing in my UVC cooler to cover everything, so 15 minute cycles would take quite a while.

when we have a lot to put thru these boxes, yes, wasting time just to overkill is kind of sloppy and inefficient.

the suggestion to get a 'petri dish sample' and try various light durations against it - that can tell you how effective it is for killing life type X. but does that apply, as well, to this virus? are things that 'generic'? (I'm no bio guy, I know software/hardware)

 

[deonb]

Is there some of a UVC permeable stable surface that can be used to create shelves?

I've read things about FEP sheets. Has anybody tried it yet?

 

[linux-works]

you could apply a layer of alum foil or like that.

I'm trying to figure out how to protect the wiring, the circuit, anything inside the box. I was not thinking about that too much before, but my design is slowly coming along and now I'm thinking about running wire conduits and just making it as uv-proof as possible (junction boxes for the arduino circuits, etc).

 

[deonb]

you could apply a layer of alum foil or like that.

Opposite problem - I want the UV to go through the surface, not be blocked by it.

 

[linux-works]

Opposite problem - I want the UV to go through the surface, not be blocked by it.

doh! didn't catch that, sorry

how about fishing line, in a row,column layout?

 

[deonb]

doh! didn't catch that, sorry

how about fishing line, in a row,column layout?

What material is that? Would UVC pass through it?

 

[linux-works]

like, thin nylon threads.

I was thinking of making this, myself. take a frame, maybe wood or picture frame - same size as the box, if you can (so it fits inside) and then use perf-board (since it has nicely spaced drilled holes) and run that along 2 parallel edges of the frame, string the nylon thread thru, with maybe 1cm square holes between them. I want to put masks or letters or whatever on such a thing and that would sit in the middle of my box. if it wears out, its not -part- of the box, it just is a removable shelf, like you said.

don't even need perf-board, but anything that helps get the spacing even would be nice. I suppose even hooks that are wood screw-ends, into a wooden frame, then nylon strung in and out, back and forth.

is that along the lines (heh) of what you had in mind?

 

[deonb]

like, thin nylon threads.

I was thinking of making this, myself. take a frame, maybe wood or picture frame - same size as the box, if you can (so it fits inside) and then use perf-board (since it has nicely spaced drilled holes) and run that along 2 parallel edges of the frame, string the nylon thread thru, with maybe 1cm square holes between them. I want to put masks or letters or whatever on such a thing and that would sit in the middle of my box. if it wears out, its not -part- of the box, it just is a removable shelf, like you said.

don't even need perf-board, but anything that helps get the spacing even would be nice. I suppose even hooks that are wood screw-ends, into a wooden frame, then nylon strung in and out, back and forth.

is that along the lines (heh) of what you had in mind?

Heh, no I want to upgrade to the next level. I have a box already with inserts. It can be better but what I’m now going for is to convert a closet to a UVC disinfecting cabinet with UVC lights on all 6 sides.

But I would want to change my 3’ x 3’ shelves to some UVC transparent material. So far the best I could come up with is quartz glass sheets, which seems like it would be a struggle to find in 3’ x 3’ in any kind of width that can withstand weight.