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Thread: For sale - high quality laser photos

  1. #21
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    Quote Originally Posted by Spec
    Thats 1/3 of what MPE covers. The other parts are duration and diameter.

    http://www.ehs.pitt.edu/lassafety/LSMApD.htm

    Scan safely. Its simple math so you have no excuse to do it.
    I'm not authorised to view the page, 403 error

    Jim

  2. #22
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    Fresh rip hosted at PL:

    http://photonlexicon.com/lsmapd.htm


  3. #23
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    Quote Originally Posted by Spec

    Thats 1/3 of what MPE covers. The other parts are duration and diameter.

    http://www.ehs.pitt.edu/lassafety/LSMApD.htm

    Scan safely. Its simple math so you have no excuse to do it.
    Diameter and irradiance go hand in hand though...

    And yes - duration as well, although the maths aren't what i'd call "simple"when you have to apply them to every frame in your show.

    *waiting for a box that can calculate it all realtime*
    Now proudly stocking and offering the best deals on laser-wave

    www.lasershowparts.com
    http://stores.ebay.com.au/Lasershow-Parts

  4. #24
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    Quote Originally Posted by aijii
    Diameter and irradiance go hand in hand though...

    And yes - duration as well, although the maths aren't what i'd call "simple"when you have to apply them to every frame in your show.

    *waiting for a box that can calculate it all realtime*
    Diameter of the iris and diameter of the beam are different, the MPE is classically calculated using the *generous* iris value of 7-8mm in relation to the beam size at the closest point where it can interact with the audience.

    Though now having read more information I can agree completely that it must be a nightmare to do all the calculations for every single frame in a show for the night...

    Sadly, I would prefer to do these calculations rather than big-government stepping in and saying "Nope! None at all!" like they do in the US.

    Well technically "none at all" is incorrect as there are guidelines to fallow to allow it but the CDRH documents specifically list Class I as implicitly ok, and asinine requirements that are admittedly tough(to impossible) to fallow for anything else.

    I'd have to find the doc but I remember it saying something along the lines of "It's ok if you dont exceed 4.99mW over a 8mm area, and have a way to automatically shut down scanning within 10mS of a beam stalling in the air" or something equally stupid.

    Id love a beam show right about now.

  5. #25
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    My brain is a bit fuzzy but, I recall being told that the very first "real" audience scanning variance was given out fairly recently in the US... I can't remember who got it though, as I was told this during a gig after I hadn't slept for a few days... The names of the folks we worked with just kind of blends together in a mash of sleep deprivation and who it actually was never made it into my long-term memory.

  6. #26
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    I think Bill Benner would be able to shed a bit of light on that one Yadda...

    Bill ?
    Now proudly stocking and offering the best deals on laser-wave

    www.lasershowparts.com
    http://stores.ebay.com.au/Lasershow-Parts

  7. #27
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    Indeed... Here's a snippet from Bills earlier post on the subject: (Skip to page 3, about 1/2 way down the list, to see his post where he talks about audience scanning.)
    Quote Originally Posted by Pangolin
    my own work in this area has recently earned us along with one other company a US CDRH Variance for Audience Scanning -- as far as I know, the first in history for what might be called "general audience scanning".
    Unfortunately, the post is right in the middle of a rather ugly thread where I displayed some unwarranted hostility towards Bill. ops: If you read through to the very end you'll see it all got worked out though.

    Adam

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