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Health effects of 254nm UV-C light

ElectricPlasma

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I've been looking into germinally destructive lighting, but couldn't find much about that specific wavelength for effects on individuals. Has anybody ever used UV-C for cleansing/germ destruction? This specific wavelength I'm referring to is 254nm, which supposedly kills germs.

Wikipedia states the following:

Wikipedia said:
The skin and eyes are most sensitive to damage by UV at 265–275 nm wavelength, which is in the lower UVC band that is almost never encountered except from artificial sources like welding arcs. Most sunburn is caused by longer wavelengths, simply because those are more prevalent in sunlight at ground level.
Can anyone confirm this? Will prolonged exposure affect health in any way? I'm thinking of keeping a UV-C light source around the workshop to sterilize goggles and other wearables. Thanks!
 

Rivem

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It will still burn you and definitely not be great for your eyes and skin. Only long term effects I could see are a slightly increased risk of skin cancer and cataracts if you don't wear good glasses. Never been burnt by a sterilizer, but if welding puts off a similar wavelength, I got one of the worst "sunburns" of my life from welding in front of a reflective surface that bounced the light behind my protection.

UV sterilization products in bio labs usually involve a box that contains the light with a safety switch in the door so that it won't turn on if open. Why don't you just make a reflective enclosure that can fit all your wearables?
 

ElectricPlasma

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Thanks Rivem, just the info I needed. I would rep you, but of course... I have to spread it around first. :p
 

Rivem

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No problem. :D

One thing I should mention in clarification is that looking directly at a germicidal lamp without protection is absolutely terrible for your eyes and probably should be treated like avoiding a direct laser beam. The burns they give are likely going to be unexpectedly quick, so avoiding any direct exposure to skin would be good as well.

My earlier remarks are in regard to more diffuse light. Either way, making a UV sterilizer cabinet seems reasonable for your application.
 

Benm

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254 nm 'germicidal' lamps are quite commonly used in laboratories working with biological material (both bacterial or mammalian cells) and are pretty effective in sterilizing whatever surface they shine on.

In these conditions you normally do your work in a flow cabinet that prevents any material from coming out towards the operator. These lamps are fitted inside the cabinet, and often switched by a timer so they turn on in the middle of the night when noone is around.

You would never work in a flow cabinet when the UV sanitazion light is on though (it can be switched off if you needed to do some work at night etc). The light from these lamps is carcinogenic without a doubt, and could cause even more problems when looked at directly. Most flow cabinets have glass shields so little of the UV light actually makes it out and the risk of looking straight into the lamp are minimal.

The lights used are usually T5 size tubes, but with a clear quartz enclosure.

They are pretty nasty things as well, and even quickly deteriorate some plastics if you leave them in the cabinet over a couple if sanitazion cycles (and yes, you are supposed to remove all of your shit from these cabinets when done, but people often leave stuff like cases of pipette tips in them).
 

Rivem

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They are pretty nasty things as well, and even quickly deteriorate some plastics if you leave them in the cabinet over a couple if sanitazion cycles (and yes, you are supposed to remove all of your shit from these cabinets when done, but people often leave stuff like cases of pipette tips in them).
In one of my labs, somebody supposedly left a burner hooked up inside a hood when the UV lamps were on. It destroyed the hose prompting my instructor to repeatedly warn students not to do it for years to come.
 

Benm

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Guess they used UV-proof gas tubing in the labs i worked at since the (foot-pedal activated) burner was permantently installed in those flow cabinets. I reckon the UV could wreck the sort of standard pink natural gas hose on most bunsen burners eventually.

Gas outlets should have some external control to switch off the flow though, and i think you are supposed to turn that off when done working.

The idea would be that you can cut off anything aiding a fire or such inside with the window slammed down completely. This usually includes electrical outlets as well. Fumehoods in the chemistry department certainly had this, i remember a vessel cracking and spilling ether while above a heater/stirrer. You certainly want to be able to lower the door when that happens and turn off all electrical power and gas supply right then and there.

The windows on these things often are not bulletproof glass or even remotely impact resistant - it's laminated glass like a car windshield at best, but often 'just' tempered glass since you have to work looking through it all the time.

Flow cabinets are good for containing any gasses etc released within them when the glass door is slid down to the proper level, but not designed to contain explosions at all.
 




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