• You must be a Supporting Member to participate in the Candle Power Forums Marketplace.

    You can become a Supporting Member.

UV TO KILL GERMS?

archimedes

Flashaholic
Joined
Nov 12, 2010
Messages
15,780
Location
CONUS, top left
That is UV-C (also called short-wave or "hard" ultraviolet light) ... very expensive emitters (for LED versions) and exposure can be quite dangerous (works by directly damaging genetic material, with dosage based on intensity x time)

Wavelength is 100-280 nm (germicidal is ~ 200-300 nm) , while most of the (LED) ultraviolet discussed on CPF is UV-A ( "blacklight" , long-wave or "soft" UV) which is considered to be 315-400 nm (although most of the common emitters are either around ~ 365 nm or ~ 395+ nm)

There are also significant exposure risks to UV-A, too, of course.
 
Last edited:

noboneshotdog

Flashlight Enthusiast
Joined
May 28, 2012
Messages
1,353
The kind that kill germs are often times used in HVAC equipment. I have one in the air supply plenum of my furnace to help with air purity.
 

noboneshotdog

Flashlight Enthusiast
Joined
May 28, 2012
Messages
1,353
There is also a ultraviolet light used to kill bacteria in well water. We put them on well water systems up here in New England from time to time. I do plumbing and heating. That's the only reason I know.
 

alpg88

Flashlight Enthusiast
Joined
Apr 19, 2005
Messages
5,282
no, your uv led flashlight will not kill any germs
 

Ken_McE

Flashlight Enthusiast
Joined
Jun 16, 2003
Messages
1,687
UV comes in different bands. We call them all "UV" because it is short and easy and for everyday speech this is close enough. The UV you find in flashlights is UV-A, around 400 nanometers and shorter which is only a little shorter wavelength than we can see. You can think of UV-A as being just a little more violet than we can observe. We use it to make things fluoresce, which is cool, and not harmful to you.

UV-C is a different animal. It is a *really* short wavelength, down around 10 nanometers, so its behavior is different. The Earths atmosphere filters out UV-C from the Sun before it gets to ground level, so nothing that lives here is really used to it, we have never had to be. When UV-C comes into contact with organic materials, like viruses, or germs, or you, it tends to penetrate into and interact with living tissues. Unfortunately this interaction is always damaging for the tissue.

With microorganisms it tends to sterilize rather than kill them. Once they can't reproduce inside you they are harmless, so we use UV-C in pipes and ducts for air and water. The air or water has to be clean though; if it is cloudy micros may survive and pass through in the shade.

If you look at the package any of those UV-C germ killing bulbs come in they are covered with dire warnings about not looking at the light. The housings that hold the bulbs are always set up so there is no line-of-sight between you and the bulb when it is on. Take those warnings seriously, and don't defeat the protective housings, The inside of your eye is built of the same stuff as microorganisms, and your eyes cannot handle UV-C any better than they do.
 
Top