What Happened to our UV-Box?May 27, 2020
by Dave Conklin
DayZero has dropped the UV-Box product from its price list. UV-Box is a dry light box which exposes objects inside to the same intensity of germicidal UV light used in our water boxes. We put it on our pricelist when we saw a do-it-yourself video circulating on the Internet on how to build your own UV light box. We realized then that we could provide a ready-made product for less than the cost of the parts in the DIY video.
We weren’t the only ones to recognize that, in the time of the Covid-19 pandemic, some people would want their own personal UV “sanitizer” device. Other UV devices are being offered for sale and other DIY videos are circulating. The Hammacher Schlemmer catalog featured a “Virus Destroying 10 Minute Smartphone Sanitizer” on the front cover of its recent catalog, and “The Virus Destroying UV Wand” on the back cover. I wrote about their smartphone sanitizer product in one of my May 13th blog posts.
But we were candid about the uncertainty around how much UV-C it takes to disinfect objects of the SARS-CoV-2 virus, the Coronavirus that causes Covid-19. I wrote about it in the other May 13th blog post, titled “How Much UV-C Does It take to Disinfect SARS-CoV-2?”. The short version is that while 40 mJ/cm2 is adequate for disinfecting water and air of most microbiological pathogens, the UV doses used by medical professionals to disinfect “disposable” masks are much higher, 1000 mJ/cm2 or more. In addition, there hasn’t been time yet to determine experimentally whether or not the sensitivity of SARS- CoV-2 to UV-C light is similar to the sensitivity of the original SARS virus, now called SARS-CoV-1.
Our water box products deliver a UV dose of at least 40 mJ/cm2 in one minute. It would take much longer, about a half hour, to accumulate the 1000 mJ/cm2 dose used in hospitals for disinfecting personal protective equipment. We concluded that it is not practical to use our UV-Box product, a dry UV light box version of our water box, to disinfect objects of the SARS-CoV-2 virus to the current, de-facto standards of the medical profession. Consequently we removed the product from our price list.
The International Ultraviolet Association has posted several documents on their website which give useful information about UV disinfection. Here are the links to two:
- Advice for the selection and operation of equipment for the UV disinfection of air and surfaces
- IUVA Fact Sheet on UV Disinfection for COVID-19.
For the truly nerdy like myself, there is a 1-hour IUVA webinar:
Expert Perspectives on UV as a Tool for N95 Decontamination
The first bullet in the IUVA’s “Advice…” piece is:
“Buyer beware! – there are few accepted standards for equipment designed for the UV disinfection of air and/or surfaces. As a result, there are many ads and promotions that claim amazing performance with little or no scientific backup.”
The IUVA advice is consistent with our own experience of looking at the ads for “UV sanitizers”. One of the presenters in their webinar said “It’s the wild West out there”. We agree.
The “wild West” comment doesn’t apply to UV water treatment, however. The figure-of-merit dose of 40 mJ/cm2 used in our water box specification seems to be well accepted in the water treatment industry. Use of UV for municipal water treatment was pioneered in Marseilles, France, in 1910, and has become widespread in the U.S. since 2003, when it was included in the EPA’s Long Term 2 Enhanced Surface Water Treatment Rule. The American Water Works Association published the first edition of its “Ultraviolet Disinfection Handbook” in 2008.