I remember that some people wanted clear fluorescent lamps, that don't produce UV. I found a fake lamp, that doesn't use quartz glass, so doesn't produce UV-C.

I have 2 germicidal lamps, a real philips G6T5, and a fake "philips" G6T5.


The real lamp was bought at an authorized philips distributor, and came in a thin polystyrene sleeve with warnings all over it. The fake lamp was included with a ballast for free, and came with no sleeve.


The fake lamp didn't even have crimps on the pins, so the lamp didn't work at first. I had to put some solder in the pins to even make it work.
Also, the etch of the fake lamp rubbed off easily.


Then, I noticed a color difference between the real and fake lamp, especially when I kept it on paper. I noticed that the real lamp made the paper glow blue (due to fluorescence) while the fake lamp made the paper glow cyan (just like the lamp itself).


Then I used a UV-C test card. The real lamp made the test card glow green, while the fake one didn't.


I have come to the conclusion that the fake lamp actually doesn't use quartz glass, and is just normal glass. The fake lamp is the equivalent of clearing the phosphor from a normal tube. That means no UV-C comes out of it.