Earlier I mentioned how we are investigating the use of Ultraviolet lights to sterilize the holiday cottage after a guest stay in these times of Covid-19. I purchased via Ebay a 60W Corncob "UV-C" lamp based on UV-C LED technology. It was despatched from China. Little did I realise that it was a fake, and while it produces a bright blue light there is little UV-C light output by the device. This makes it useless as a biocidal lamp.
This is a picture of the lamp I purchased:
I was alerted to the possibility of the fake, by this Youtube video:
I'm in dialogue with the Ebay vendor to assess their reaction. So far all they have claimed is that the have a CE certificate, with no offer of a refund. The image they sent me was of a certificate issued in China about two weeks after the date of my purchase. On investigation the tests performed by the laboratory in China relate only to electromagnetic interference with other devices and the level of "flicker". The CE test did not measure the UV-C output from the lamp. I am arranging for my lamp to be tested against a laboratory UV-C light meter. At a cost of £850 these meters are not cheap, and finding a company to perform the test was a challenge, but I am expecting to receive the results in a couple of weeks..
Here's an expert view on using UV-C for disinfection: http://www.iuva.org/IUVA-Fact-Sheet-on-UV-Disinfection-for-COVID-19
and a different Youtube lecture https://www.youtube.com/watch?v=uqSHPKicIbs
Amazon introduce a campaign against counterfeits, unfortunately this will not guard against products that make fake claims about their capabilities such as these "LED UV-C" lamps. Their measures only relate to protecting trade marked original goods. I eventually purchased a genuine UV-C Lamp from a UK supplier, details here.
We've had the results back from the laboratory. From the fake corncob lamp the UV-C reading is 7 microwatts/Sq Cm (254 nm UV) at a measured distance of 5 cm from the bulb. From a comparative "daylight white " 5 watt LED domestic bulb the same 7 microwatts/Sq Cm. In other words the fake UV-C corncob lamp has no more disinfecting power than a normal LED bulb.
By way of comparison a 73W mercury vapour UV-C germicidal lamp gave a reading of 7.17 milliwatts/sq cm measured at the same distance from the lamp surface. It is about 1000 times more powerful.
The vendor has disappeared from Ebay; though these fakes are still on sale on both Ebay and Amazon. I've reported a few cases but Ebay and Amazon do not appear to be interested.