"Paul M. Eldridge" <paul.eldridge@ns.sympatico.ca> wrote in message
news:iar3v2dddptohmn6gf311nk30d2pfqvp52@4ax.com...
There seems to be a genuine concern over the mercury contained within
CFLs and the potential health and environmental risks this represents.
Looking at reader feedback to various media coverage you see this come
up time and time again, and you get the impression some folks view
CFLs much like toxic nuclear waste.
So with that in mind, I wanted to get a better sense of how the major
lamp manufactures compare, but this hasn't been as easy as I had
expected.
As a starting point, the EPA tells us a typical CFL contains 4
milligrams of Hg.
Source:
http://www.nema.org/lamprecycle/epafactsheet-cfl.pdf
According to GE's website, the average is 5 milligrams (close enough).
Source:
http://www.gelighting.com/na/home_lighting/ask_us/faq_compact.htm
The data for Osram Sylvania suggests mercury content can vary
considerably (i.e., from less than 1.8 mg to just under 15 mg) but,
for the most part, it falls within the range of 3 mg to 5 mg.
Source:
http://www.sylvania.com/content/display.scfx?id=003690938
Lastly, we have Philips and in the case of their "Extreme Low Mercury"
line, these numbers are reported to all fall below 2 mg.
Source:
http://www.lighting.philips.com/gl_en/news/press/sustainability/archive_2006/reduction_in_mercury.php?main=global&parent=4390&id=gl_en_news&lang=en
But here's where things get a bit murky for me. I had initially
thought the "Extreme Low Mercury" line might be the same thing as
Alto, but that's not the case. For example, the 25-watt Marathon
Universal, which proudly wears the Alto badge, contains 2.64 mg of Hg.
So are these "Extreme Low Mercury" lamps available only in Europe and
is this designation something different from Alto? Or is it a case
that the numbers for Alto will eventually drop over time?
Philips has kindly listed the mercury content of specific Alto and
non-Alto CFLs, but not all (e.g., their popular "Twister" line). It
would be helpful if manufacturers were a little more forthcoming with
this information, so that we, as consumers and specifiers, could make
better-informed choices.
Cheers,
Paul
From a quick visual inspection, in one of the OSRAM DULUXSTAR 21W/827 lamps
which are used in my mother's kitchen, I can discern a tiny ball of Mercury
which has condensed at the bottom of the tube.
The ball has roughly a diameter of 1mm by inspection. Assuming that's that
most of the Mercury in the tube and assuming the little ball is roughly
spherical (which because of surface tension on such a tiny amount is not a
very unreasonable assumption), plugging r = 1/20 cm into the formula for the
volume of a sphere, V = 4/3 * Pi * r^3, and then multiplying that with the
density of Mercury d = 13.5 g/cm^3, I get:
0.007 g = 7 mg, which seems to be close to the values reported on your
references above, albeit on the high end.
