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(Chris Lewis) wrote in
:

According to Ignoramus4324 :
Thanks. You raised a great issue and I would not want to take any eye
damage risk. Would it make any sense to enclose them into some
appropriate (rated for heat input) glass diffusers of any sort? Glass
is a UV filter, right?

It looks as though going with more regular fluorescents may be more
sensible though.

I'd recommend the fluorescents for several reasons entirely aside from
potential UV emission.

- MH bulbs are _hot_. In a smallish area (a garage would qualify),
the directed heat will occasionally be uncomfortable.

- MH systems are expensive.

- Used as overall lighting in a relatively low-ceiling space, MHs
will have intense hard-to-miss super bright spots, which will have
you stumbling around with purple spots in your eyes.

- I'd rather not have MH bulbs in a workshop, where accidentally
hitting one will let stuff out that you don't want...

- MHs are somewhat more efficient than ordinary incandescents, but
not nearly as good as fluorescents, and as such, going with a lot
of MHs to get a lot of light is going to cost a fair bit to operate.

Your best bet is to use fluorescents as overall lighting, and use
floods or spot lamps in work areas where you need it.

I've built my shop with several 8' fluorescent fixtures for
overall lighting, and used a variety of quartz halogen fixtures
mounted on the ceiling for task lighting. In order to keep costs down,
I've used a few 150W and 300W rectangular QH flood lamp fixtures (long
skinny QH bulbs) - they're quite cheap. Even cheaper are simple
flood lamp holders with PAR30 QH bulbs (45-60W), tho you can up 'em
to PAR50s (up to 300W, but I'd stay below 100W because of heating
issues) if you wish.

Note that these fixtures are not normally indoor ceiling mounted,
and you need to be aware of the fact that they do produce a lot
of heat. The ceiling of my shop is drywalled... The inspector
didn't question them either.

Note also that I have to be careful not to run into them with
large pieces of lumber. Pot fixtures would be nicer, but they're
not as flexible. In 10 years or so, I've not broken one yet....

One other note;I worked in a lab with MH lighting,and any brief power
interruption meant we went without light for the time it takes for them to
cool and then re-ignite,about 15 minutes,IIRC. A PITA.
Our lights had UV filters,and reflected off the white ceiling.
I would not want them in my home.

--
Jim Yanik
jyanik
at
kua.net