UVC safety demo for my colleagues

A demo of what a UVC tube looks like when lit. They are a very pleasing ghostly blue, which unfortunately means that people have accidentally used them as a decorative item with painful results.

Everyone in the room had glasses on that blocked UVC. Most ordinary glasses and plastics will block it. It's actually harder to find materials that allow it to pass through.
We left the room for a while to allow the tube to come up to full power.

Note that defeating the safety shutter in a socket by shoving a metal key in the earth hole and then ramming bare wires into the live and neutral holes is not a recommended connection method, and poses a high shock risk.

UVC tubes are used for germicidal purposes in food processing equipment and in medical applications. There are two common types with different glass filtering properties. The classic germicidal tube only passes the 254nm wavelength from a mercury vapour discharge, but there are versions like this one that also pass the 184nm peak that breaks down oxygen bonds in air and allows temporary formation of short-lived active air molecules like ozone.

If humans or animals stare at a UVC tube it causes a temporary effect called photokeratitis which is the same painful effect experienced by being exposed to arc-welding flash (also strong UVC). There is a delay before the symptoms set in and it feels like sand in your eyes. But the discomfort will soon pass. If needed, medical intervention will offer a mild anaesthetic for the eyes to suppress the discomfort. A classic welders trick is to slice raw potato and apply the juice to the eyes - but I can't offer that as official medical advice.

High exposure can also cause surface damage to the skin, but contrary to a previous belief that it posed a risk of causing skin cancer, the UVC wavelength is so short that it can't pass deep enough into the skin to reach the critical areas. UVA and UVB pose a much higher risk in that area.

Two notable events where the organisers used high power UVC tubes as decoration were Hype-Beast and a "Bored Ape Yacht Club" event. Both resulted in high admissions to hospitals for skin and eye issues.

Other common accidental exposures are in the HVAC industry when workers open duct inspection panels where there are UVC tubes present, and when maintenance operatives accidentally use UVC tubes in place of the similar colour UVA ones in insect traps.

Most UVC tubes are identifiable by being clear glass instead of the white phosphor coated glass of traditional fluorescent tubes.

If you have a need for a small UVC germicidal tube then this one came from AliExpress, complete with an ungrounded fitting and internal ballast. Here's an affiliate link if you want one:-
https://s.click.aliexpress.com/e/_c2vyTqmB
If you do get one, make sure you store it in a box clearly marked with hazard warnings about UVC light.