Germicidal Ultraviolet Light

There is a great deal of interest in the use of ultraviolet light to mitigate germs and viruses. The technology of germicidal lighting is referred to as germicidal UV, or GUV. Technically, the GUV spectrum is defined as UV-C. While the UV-C part of the spectrum is an effective killer of COVID-19 and similar viruses, it must be used carefully to be both effective and safe. Information on this site is compiled to help promote the safe and effective use of GUV in residential settings.

 

 

See a quick guide to UV light, or scroll down for a deeper dive into the topic.

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Germicidal Ultraviolet Light - Technology Newsletter

April 2020
 
April 22, 2020
 
As an industry that is being significantly impacted from the ramifications of COVID-19, it is important to gauge the opportunities in front of us and how we can differentiate our businesses moving forward. Our top priority is to do everything we can to help our members and the lighting industry remain healthy, both in body and business.
 
Terry McGowan, FIES, LC
Director, Engineering & Technology
 
 
 
Newsletter Sponsor:
 
Germicidal Lighting – Is It for Homes?
 
Suddenly there is a growing interest in germicidal lighting. A quick look online or at manufacturers’ literature and websites shows a proliferation of germicidal lighting equipment from permanently installed luminaires to portables, including light wands and screw-in germicidal bulbs, all designed to decontaminate objects, materials or surfaces. The interest, of course, is driven by concerns about COVID-19.
 
Is this a technology that should be embraced by our industry? 
 
I’ll answer that quickly – Yes, it’s an opportunity, but it is also more complicated than picking a lamp or luminaire out of a display or catalog; and some design work (much like lighting design) may be required. Most important of all, there are safety concerns because germicidal lighting products can cause eye and skin damage to both humans and pets. Home furnishings, including wood, plastics and fabrics, can be damaged as well.
 
Germicidal UV or GUV refers to the technology of germicidal lighting, which utilizes ultra violet light sources. Technically, the GUV spectrum is defined as UV-C, which ranges from 200 to 280 nanometers (nm). 
 
There is another band in the UV spectrum called UV-A that is also getting attention for residential germ-killing properties. The UV-A wavelength range is from 315 to 400 nm and includes what used to be known as the blacklight region of the spectrum. Traditionally, so-called BLB (blacklight blue) lamps were (and still are) sold for insect traps, and theatrical and special-effect lighting where glow-in-the-dark effects are desired. Such lamps and lighting products have limited germ-killing power, and typically require long exposure times to be effective. According to a new report from the IES, UV-A blacklight lamps are not effective against the COVID-19 virus.
 
GUV lighting in the UV-C part of the spectrum is an effective killer of COVID-19 and similar viruses, but it has to be used carefully to be both effective and safe. The just-released IES Committee Report mentioned above includes an excellent FAQ on GUV, and is available as a free download. Go to: http://alturl.com/i8xzg and click on “Download Committee Report CR-2-20-V1”.
 
Those wishing additional information about GUV technology are invited to view a new video from the National Lighting Bureau featuring experts from the Lighting Research Center. I was pleased to be part of that video and to ask questions that apply to our residential lighting concerns. The video can be accessed at: http://alturl.com/tot2s
 
GUV lighting in the UV-C part of the spectrum is an effective killer of COVID-19 and similar viruses, but it has to be used carefully to be both effective and safe.
 
And, lastly, some cautions:
 
  • Insist upon and read carefully all GUV product safety and caution notices. If none are provided, ask the manufacturer. If you feel the information provided is incomplete or hard to understand, consider not using the product.
 
  • Germicidal lighting works only via line-of-sight. Reflected light does not kill germs because most reflecting surfaces in homes absorb the critical UV-C wavelengths.
 
  • Exposure matters. Exposure = Intensity x Time. Like sunburn, damage to skin and eyes results from being exposed for too long to the light source. GUV exposures, however, are likely to be measured in seconds and minutes, not hours.
 
GUV is a good way to help control the spread of the COVID-19 virus. Learn the facts to apply it effectively and safely. Be safe and well.
 
Sincerely,
 
Terry McGowan, FIES, LC
Dir. of Engineering & Technology
American Lighting Association

 
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