Cheap lasers not legal?

Ron Kimball

Senior
Mar 5, 2011
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16
NE CT
A band I sometimes provide for has two of them cheap banjo center RG laser effects they aim at the dance floor. So I figured I'd order a couple up from fleaBay for $15 each shipped. They are pretty similar - 100mw red and 50mw green lasers. Question is how is it possible to operate these without a variance? Even the American DJ and Chauvet manuals warn against aiming them at the audience - even though their videos show them aimed at the dance floor. One manual explains theirs is a Class IIIR device due to the beams being permanently split such that each is under 5mw. AFAIK the FDA doesn't allow these Class IIIR/IIIB devices to be downrated to Class IIIA just because the beams are permanently split and even if so requires a variance above the Class II level - and doesn't allow beams over 0.39mw to be aimed at an audience. In any case mine are stickered Class IIIB unlike the ADJ & Chauvet ones which I assume are stickered as Class IIIR.
 
Re: Cheap lasers not legal?

Interesting FAQ Sam's Laser FAQ - Laser Safety

In particular someone rang up the FDA's CDRH and ask the following question:

Question: If a laser puts out more than 5 mw, but through the use of
a beamsplitter, diffraction grating, filter, or other device the
resulting beams that exit the projector are EACH less than 5 mw, is
the show still considered "under 5 mw" and thus exempt from a
variance?

Answer: Yes. As long as the beams that exit the device (projector,
housing, etc) are each less than 5 mw, and the beams are separated far
enough apart such that it is not possible for multiple beams to enter
the same pupil, then the entire device is exempt. Thus, you can have a
20 mw laser putting out, say, 8 beams from a diffraction grating, and
as long as none of the beams are over 5 mw the entire setup is exempt.

As an aside, he went into considerable detail as to how these beams
would be measured for intensity. The basic standard is to use the
standardized pupil diameter (listed in the CDRH main document - I
forgot to write it down) and measure the power at a minimum distance
of 20 centimeters (!) from the apparent source of the laser light.
(i.e., the window on the projector housing, the aperture of the scan
head, or the output coupler of the laser if the other two do not
apply.) The pupil size used for the calculation changes if the
environment is such that it would be likely that audience members
would be using binoculars. Binoculars?!? I asked?: "Yeah, like in a
large arena - folks typically bring a set to make it easier to see the
stage." He floored me with that one, but it makes sense if you think
about it.