In a moment of interesting technical exploration and spirit of “How does that work then?”, we decided to have a quick look at some UVC germicidal lamps being sold on Amazon.
You’ve probably seen the sort of ad, which look something like this below, with lots of nasty bugs and viruses crossed out…
Not particularly cheap at £20.64 + £8 delivery, must do something good then for that money, eh?
So we gathered some examples of things from Amazon that claim to be UVC germicidal lamps, and one from a UK specialist…
The two LED lamps and the large 55W compact fluorescent (CFL) are from Amazon, the smaller 9W CFL from the UK specialist
We tested the lamps from Amazon with a meter that measures UVC in the ~250nm wavelength range, as used for germicide. So what did we find?
Here is the first small LED lamp (actually the one in the ad screenshot above)…
De nada! Really wimpy, it’s just an ordinary slightly blue LED lamp. So it’s fake.
This is the big beast LED – claims to be a 75W UVC lamp…
Ouch, it’s really bright – but no UVC! Another fake.
And here is the large 55W CFL…
Yesssss, it produces UVC, that’s 3.27 mW/cm2 – quite nasty, and the tell-tale smell of ozone from oxygen broken down by the emissions.
So we did the test again, to see the intensity right at the device itself
That’s an even nastier 13.07 mW/cm2.
The EU recommended exposure limit for UV (inc. UVC) is 30J/m2 over an 8 hour period, so up close you would exceed that in just 0.2 seconds! Even at 2m, it would only take only 1.5 minutes to exceed the limit, and the ozone produced is unhealthy too.
So don’t look at them and probably don’t use them at all! If you do have to work with this sort of lamp use UVC opaque safety equipment, and certainly don’t use them as party lights like they did at this pop-up club here!!!
So the upshot from this brief investigation is:
- if the claimed UVC lamp has LEDs and the price looks good, then it is not a UVC lamp. Since real UVC LEDs are still expensive, you ar eunlikely to find them on Amazon
- If it is a CFL, then it may be the real thing. However, we can’t recommend them as UVC can damage the eyes, and their use can be hazardous, unless handled properly
So there you go…