I've had a germicidal lamp more or less in storage for a number of years, but recently brought it out to sterilize a room where a person had been sick. However, I don't know if it still emits the germ killing UVC spectrum. What's a quick way I could tell for sure? Thanks.
illing
nks.
Inverse square law makes your idea not so practical, aside from the inherent dangers of exposure to raw UV light!
Better to wash the room down with a disinfectant, or simply air it out for a while...
If the person was very contagious then look up the procedures for dealing with that rather than making up your own potentially dangerous ones.
John :-#(#
? Thanks.
I'm well aware of this after having used such lamps in the past.
The problem is that there are dogs and cats present and the room I want to sterilize is in a relative's house. They own the pets, but I haven't
had a pet in over 40 years. If I were disinfecting my own room, I might
use 70% iso rubbing alcohol in sprayer format or even a weak bleach solution, but animals pretty much rule out either chemical. At least with the lamp, there are no residuals other than perhaps weak ozone that
can be aired out quickly.
Trying not to make this complicated. All I wanted to do was see if the lamp was in fact still producing the necessary UVC spectrum. Surely, there should be something on the market that perhaps fluoresces only when UVC illuminates it. Or something similar and relatively simple.
a) Neither cats nor dogs are threatened by a low concentration of either bleach or isopropyl alcohol. b) Anything over 10% alcohol or 0.5% sodium hypochlorite is an effective germicide & viricide. c) Common 80-proof Vodka cut 4:1 is also very effective, and leaves no residue.
With that in mind, and the exposure requirements for UV to be effective, you would be far better served to use an alcohol solution. Which has the additional virtue of being able to get behind and into cracks and corners where light will not.
Do also research the viability of the infections involved over time, tolerance of temperature extremes, tolerance of humidity extremes and so forth. And, just for giggles, look up Hospital patient room discharge requirements.
Peter Wieck Melrose Park, PA
I see UVC covers 200nm to 280nm. I don't know anything about UVC bulbs so I need to ask is does yours have a specific wavelength output? Like
270nm? My limited search finds bulbs of 254nm to 270 nm. I did a little searching and didn't find anything in the way of UVC sensors. But maybe a way to back into it? Adafruit has a UV sensor that works from 240nm to 370nm for $6.50. Maybe buy a filter for UVA and UVB, to cover that sensor and see if it senses any UVC. OR buy a UVC sensor and flip flop covering and uncovering the sensor and see if you get a square wave output.Mikek
I should have posted the sensor.
and the adafruit pcb.
Lots of cloth material made out of polyester that is white will have a chemical in it that glows under the UV light.
Try taking several pieces of white clothing and even the white thread that some buttons are sewen on with will work.
Where I worked making polyester sandoze was added to the material to make the whites even whiter. That glows under UV light.
Cat piss. Cat piss shows up quite bright under UV light.
Glad to help, Jonesy
--
Marvin L Jones | Marvin | W3DHJ.net | linux
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Ummm... perhaps a UV-C light meter? Something like this: Response is 246-262 nm with a UV-C pass filter.
More of the same: Typically $350 to $1,100. You might want to look into borrowing or renting such a meter.
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
You would think that China would have some for way under $50 . While they may not work the best, China seems to have almost every thing else very inexpensive.
Bad to pay $ 300 + to check out a $ 20 or so light.
I couldn't find anything from China that is substantially cheaper:
The bulk of the cost seems to be in the sensor and the UV-C filter.
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
It'll embrittle plastic quick if it's really UV-C; a disposable bag turning to dust would convince me it was shining. Or, you could imagine something with a slit, telescope mirror, thermopile, and grating, if intensity measurement was important.
I'd think of something quick-and-dirty before shelling out bucks.
Not so long ago, someone here stated that this group exists to teach gullib le individuals how to do things the hard way (as opposed to the correct way , or the effective way. Emphatically not the 'easy way').
This thread is a very nearly perfect example of that process.
a) Whereas light on the correct UV spectrum *will* kill many (not all) micr obes and such, it is not designed against the stated purpose. As an Ozonato r in a water sterilization device, fine. Or in a fume-hood.
NOTE FROM SECONDARY SOURCE: Germicidal lamps emit radiation in the UV-C po rtion of the ultraviolet (UV) spectrum, which includes wavelengths between
100 and 280 nanometers (nm). The lamps are used in a variety of application s where disinfection is the primary concern, including air and water purifi cation, food and beverage protection, and sterilization of sensitive tools such as medical instruments. Germicidal light destroys the ability of bacte ria, viruses, and other pathogens to multiply by deactivating their reprodu ctive capabilities. The average bacteria may be killed in 10 seconds at a d istance of 6 inches from the lamp.b) That form of UVR that is effective in killing pathogens will also damage humans.
NOTE FROM SECONDARY SOURCE: UVR is not felt immediately; in fact, the user may not realize the danger until after the exposure has caused damage. Sym ptoms typically occur 4 to 24 hours after exposure. The effects on skin are of two types: acute and chronic. Acute effects appear within a few hours o f exposure, while chronic effects are long-lasting and cumulative and may n ot appear for years. An acute effect of UVR is redness of the skin called e rythema (similar to sunburn). Chronic effects include accelerated skin agin g and skin cancer. UVR is absorbed in the outer layers of the eye ? the cornea and conjunctiva. Acute overexposure leads to a painful temporar y inflammation, mainly of the cornea, known as photokeratitis. Subsequent o verexposure to the UV is unlikely because of the pain involved. Chronic exp osure leads to an increased risk of certain types of ocular cataracts. Working unprotected for even a few minutes can cause injury. It is possible to calculate the threshold for acute effects and to set exposure limits. I t is not possible, however, to calculate threshold for chronic effects; the refore, because no exposure level is safe, exposure should be reduced as much as possible.
c) If one takes the 30 seconds or so to research how UV light is used in la boratory settings to sterilize equipment, surfaces and instruments, one wil l see that, again, it is not indicated for the purpose stated hear.
Bottom line: UV light is not indicated. UV light is dangerous. UV light is not 'quick' either. To do what is required per the OP is good old 'asses an d elbows' work, not the waving of a magic wand or, pun intended, light sabe r.
Put another way: There are two issues here: #1 is the sterilizing of a sick
-room after the fact. For which UV light is neither safe nor effective. #2 is to determine if any given UV lamp is still emitting over the target freq uency(ies). And that may be had right off the shelf, cheap:
And thousands (yes, thousands) of other sources.
Peter Wieck Melrose Park, PA
No one has responded to my post. Is there anything fundamentally wrong other than the cost of filters is high and the sensor has it weakest response in the UVC wavelength. I don't mind the idea getting shot down, I'd learn something.
Mikek
the
way of UVC
or $6.50.
wrong
Hi Mikek,
While your information may be valid, it is of little use to the OP to try to use a UV bulb to sterilize the room. It would be dangerous to his
eyes and or skin, and it would be ineffective as the UV only would effect microbes that are on a surface the UV light would strike, plus the UV light has to be near (under 1 foot typically) to have a high enough concentration and it needs to light up the organisms for up to five minutes to be sure of killing them. Thus you have to hold the UV lamp for five minutes over every square inch of the room and you won't get any of the crevasses at all!
So totally impractical.
On the other hand if you made a separate posting under the topic of tools to measure UV bandwidth (or similar) you might get more bites!
John :-#)#
the
way of UVC
or $6.50.
wrong
On some work sites, you see the plumbers or steamfitters welding (tig) blac k iron pipe, creating light that could hurt the cornea of un-protected eyes . How would germs stand up to that spectrum? You have to wonder.
s the
or
m.
he way of UVC
m for $6.50.
lly wrong
is
black iron pipe, creating light that could hurt the cornea of un-protecte d eyes.. How would germs stand up to that spectrum? You have to wonder.
Welding light is very dangerous, but the OP was talking about a fluorescent UV sterilizing lamp. Completely different levels of intensity .
One could as easily say a nuclear bomb (or the surface of the Sun) is hard on bacteria...
John :-#)#
It's a good question (if not a good use.) Amazon is full of air purifiers that include UV light inside the enclosure. That light must degrade over time, if it even works at all.
A quick google says change the bulb every 12 months. I bet it isn't cheap, either.
So, A your lamp probably kills germs for about 6 inches, and B it's probably worn out by now anyway.
g
s that include UV light inside the enclosure. That light must degrade over time, if it even works at all.
p, either.
bly worn out by now anyway.
Snip from a UV website:
******** What distance and how long would I have to expose an article to germicidal ultraviolet to sanitize it? The exposure necessary to inactivate microorganisms is a product of time an d ultraviolet intensity. High intensities for a short period of time, or lo w intensities for a long period of time are fundamentally equal in lethal a ction on infectious microorganisms. As a rule of thumb, at two inches awaya and virus are inactivated within five seconds of exposure. For specific r ecommendations, please call our staff with the details of your application (including area available for the fixture, how far the fixture will be from the article, etc.) The more information you can provide, the better.
The second best way [a] to clear out microbial nasties is via hydrgen perxide misting. The equipment is still quite expensive and rare, but gaining traction in hospitals and other high risk areas.
Here's a technical/medical professional article about it:
And a markting quasi advert:
You might, emphasize might, be able to find a local source of this type of equipment for rent.
(Probably not at any reasonable price).
[a] the first is via high intensity radiation. I doubt you'd find that a plausable option.-- _____________________________________________________ Knowledge may be power, but communications is the key dannyb@panix.com [to foil spammers, my address has been double rot-13 encoded]
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