Forum for Illumination Research, Engineering, and Science (FIRES)

Category: Ultraviolet Radiation
By Ian Ashdown, P. Eng. (Ret.), FIES
Senior Scientist, SunTracker Technologies

Visible light disinfection is a lighting industry innovation wherein violet light is claimed to inactivate pathogens such as bacteria and viruses.
By Michael L. Grather, CTO, LightLab International Allentown, LLC We have all seen the wide range of new products claiming to be effective against pathogens of all sorts. Common claims range from the rather ambiguous “fights germs” to the more specific but questionable claim “can disinfect up to 40 square meters of the surface at a time.” Maybe it’s just the times we’re living in, but my first reaction is to take a very skeptical view of these claims. It also seems that I’m not the only one. My neighbor, who is not in the lighting field, asked me if I thought “these UV lights” are safe. Almost without taking another breath he followed it up by asking “… do they actually work?”
By Ian Ashdown, P. Eng., FIES Senior Scientist, SunTracker Technologies Ltd. A word of caution: I am going to be annoyingly pedantic here, but with good reason. The lighting industry has a century-long history of introducing unfamiliar technologies using familiar terminology. We later come to regret our choice of words when it becomes necessary to express precisely what we mean.
By Ian Ashdown, P. Eng., FIES Senior Scientist, SunTracker Technologies Ltd. Germicidal lamps emitting ultraviolet-C (UV-C) radiation have been in use since the 1930s (Wells and Wells 1936). These are most commonly low-pressure mercury-vapor discharge lamps, which are basically fluorescent lamps without a phosphor coating and fused quartz rather than borosilicate glass bulbs. They emit monochromatic radiation mostly at 254 nm, a wavelength that is very effective in disrupting the DNA of viruses, bacteria, and other pathogens.
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