In James Reaper writes:


Odd. I still have an outdoor mercury lamp on my property, a 250 W
lamp. I just replaced it last year and the UV warnings were still
present concerning breaking the outer envelope. So they would
definitely still emit UVC if the envelope was broken.

Amusingly the ones I purchased didn't have thos waarning.

I think... they were 185 watt replacements I picked
up at Home Depot. (No one else had them).

Ways of getting around the UVC hazard included shutdown mechanisms so
that the lamp extinguished when the envelope was broken, providing a
lamp housing that has a glass cover (like street lights have), or
switching out to something different altogether where the UVC hazard
doesn't exist such as LED. There's been an ongoing effort to outlaw the
mv lamps.

New fixtures/ballasts have been a no no for a decade or
so by now, and replacement lamps have been attriting down.

About ten years ago I found a drop-in flourescent replacement
for the aforementioned 185 watter. The power factors/wave forms/
how it worked... made my head hurt, but somehow it did.

(We've since swapped the whole fixture for an LED unit).

Oh, here we go:

[Duromex, the successor to Duro Test, website]

"1975: Securilux (Safe-T-Vapor)

"This was the first mercury lamp with a safety mechanism that
extinguished the arc tube in case of an exterior light bulb smash. "

http://duromex.com/about

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