Laser show safety

I recently was at a local roller skating rink and noticed they had upgraded some of their lighting. They used to have the good old classics like neon and large set of disco-balls but they recently added in some lasers.
They have 2 mounted on each end of the rink.
They are sound controlled green laser spiro graphs.
They have them setup to scan the crowed and they meet in the center of the ring.
With this they also have a 1000 watt fogger.

I wanted to know if this seems safe.
The famous "what if" the motors broke and the beam went stationary, what safety measures are in place?
The units were posted here on lpf trying to dig them up for pics.
i have a 50mw green and the beams looked just like it when i put mine into my spiro graph.
I live in the USA, Michigan to be specific and could not find any official information about laser shows and how to conduct them.
If you have any documentation would you please link it.
I do not want to shut them down or have them stop as it was very cool but to let them know they are running a risk and that the technology they are playing with is not harmless.

Where did these lasers come from?

If they got them installed, i'd assume the company installing them should be responsible for the safe operation of the show.

Practical what-if: If the motors (or galvos or whatever moves the beam) fails, there should be failsafe that closes a shutter and/or shuts down the laser quickly. I doubt any 'spiro' construction would be able to detect this, whereas a galvo driven system could be able to use the feedback signals from the galvos to assert they are still moving.

21 CFR 10.1 SUBCHAPTER I and SUBCHAPTER J


Responsible agency is the Center for Devices and Radiological Health, a division of FDA.

An Audience member cannot be subjected to radiation in excess of class I.

If you have questions contact your REGIONAL EOS

James E. Frye in Cincinnatti, Ohio 513-679-2700 ext l49 :can:

It is so highly unlikely that those units have a scanfail that I could bet 3 months pay on the subject.. (I almost typed "title to my equinox")


Steve

You mean its unlikely that their scanners will fail, or that its unlikely they have any safeguard in case it does?

I'd agree on the latter given their relatively low power level. I suspect the installation is simply not fit nor safe for audience scanning, but is misused here. Reading the story as it is, i suppose they just put up 2 cheap 'disco lasers' that are intended to be pointed at the ceilig or the wall where no audience can get in the beams way...

Right. Most likely they're Chinese toy projectors. They can be very unsafe since there is no circuitry to protect against accidental static beams, but it does depend a bit on the power output. If they're very weak and placed a good distance from the audience, the danger exists but is very minimal. As a rule, no audience contact unless you have the necessary permits (which you can't get unless your equipment is approved) and you have done the math required to guarantee safety.

Now this is where there should be an official document from a government site with this info. or is there and i am not finding it?
I would like to be able to email them some sort of document showing what they are doing is risky and not just a self made write up.

There are guidelines on the acceptable power densities and exposure times for laser shows, also where the crowd is scanned. I'm sure someone with more experience in the field can point you in the right direction for those.

I doubt the equipment used is certified for any of those parameters though, so it would technically be a no-go until it is.

This is badly outdated, it still assumes outside companies do shows in a venue:

http://www.fda.gov/downloads/Medica...onandGuidance/GuidanceDocuments/UCM119257.pdf

Laser Light Shows

Steve