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Safety screens in Par-cans

Discussion in 'Lighting and Electrics' started by Dustincoc, May 8, 2008.

  1. Dustincoc

    Dustincoc Active Member

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    How important are they? We a couple of units that have them but the rest don't and I haven't seen any laying around either. Do Parcans all have safety screens/can they all have them? It's a mix/match of brands. They are all par64's though.
     
  2. highschooltech

    highschooltech Active Member

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    I would say that they are not all that important as long as the lamp will stay seated without them.
     
  3. thorin81

    thorin81 Active Member

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    Many older PARs do not have the screens, that tends to be a newer addition to the instrument. It is not a big deal that they don't have them. The retainer ring that holds the lamp in place in the can should be enough. As far as I know you cannot even buy a seperate screen for the PARs that do not have them... but don't quote me on that.
     
  4. derekleffew

    derekleffew Resident Curmudgeon Senior Team Premium Member

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    Quoting you even though you said not to. Sorry. Altman sells Safety Screens for its PARs.

    The screen is there not to keep the lamp in place, but to prevent large shards of glass from falling onto the stage/audience should a lamp shatter. I've never seen it happen, but someone must have, as sometime in the 1980s all manufacturers started including them. This is the same reason overhead cyc lights' colorframes have screens built into the color frame. Double-ended T-3 type lamps do explode, and the rumor is open-faced fixtures have been banned from use in some Convention Centers/Trade Show Floors.
     
  5. highschooltech

    highschooltech Active Member

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    That seems rather strange if the lamp goes pieces that are smaller than the screen holes are going to come out.
     
  6. lieperjp

    lieperjp Well-Known Member

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    Well, they wouldn't be as dangerous as a large piece, though. Larger pieces have more momentum... But I can't see any piece doing significant damage to a person unless it's A) Really Sharp, B) the whole front of the bulb, and therefore, C) really heavy or if it drops more than 150 feet. Though I haven't double checked all my physics calculations :rolleyes:

    Either way, the pieces are dangerous because of the heat, if those get stuck on a person, ouch. Also, if the base comes off the light, it would prevent a large metal/ceramic chunk from knocking on someone's head.
     
  7. DAE

    DAE Member

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    In Australia there is an Australian Standard AS/NZS 60598.1:2003 Luminaires Part 1: General requirements and tests (IEC 60598-1:2003, MOD)

    4.21.1 Luminaires incorporating tungsten halogen lamps, without an integral outer envelope,shall be fitted with a protective shield except when the lamp is:
    – a mains voltage (general lighting source) replacement lamp;* or
    – a low pressure tungsten halogen lamp as specified in 9.1 of IEC 60357.
    4.21.2 Parts of the lamp compartment shall so be designed that particles from a shattering lamp cannot impair safety.4.21.3 All openings in the luminaire shall be such that no parts of a shattered lamp can leave the luminaire by a direct path, including the rear of recessed luminaires.
    4.21.4 Compliance with 4.21.1 to 4.21.3 is checked by inspection and by the following tests:
    – the protective shield shall comply with the impact test of 4.13.1 with the impact energy of table 4.3 for fragile parts;
    – parts of the lamp compartment, if of insulating material, shall comply with the resistance to flame and ignition test of 13.3.2.
    NOTE 1 – This requirement is intended to improve safety by eliminating the hazards due to chance failure of a lamp or incorrect application. Existing open luminaires not fitted with a protective shield do not necessarily present a hazard.
    NOTE 2 – The impact test of 4.13.1, which is performed from the outside is regarded to be more severe than the impacts of glass particles. A specific test simulating the latter is therefore not necessary. In case the mounting means of the glass shield is solely designed to withstand impacts from the inside, the test of 4.13.1 should be performed in that direction.

    These standards are not mandatory but state workplace health and safety legislation makes it compulsory to provide a safe working environment and these standards are used as guidelines to measure how it may be done. These standards are usually derived from European standards IEC.

    These standards are written in a generic vague style, so you will not be able to look up Par64. In this case it says "4.21 Protective shield (tungsten halogen lamps)".
     
  8. Footer

    Footer Senior Team Senior Team Premium Member

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    Seen it happen. Was working in a space that had Par56 Lamps mounted in ceiling house light fixtures (NOT par fixtures, but took standard par lamps). No safety screens of course. Also happened that this places house light system consisted of flipping breakers backstage, no dimmers. Called a house up cue, person started flipping breakers, a lamp exploded and shards of glass rained down. Luckily no one was in that section of the theatre, but it did happen. We then installed screens on everything. I think what happens is if the inner lamp blows properly, it can raise the pressure inside the lamp and cause the lamp to burst. Ship?
     
  9. TimMiller

    TimMiller Well-Known Member

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    I have seen par lamps blow numerous times (thankfully never during a show, usually always happens during setup), big boom and glass comes falling out of the fixture, unless held in by a screen (most of ours dont have a screen in them) or the gel keeps most of the glass from falling out. When there isnt any gel it makes a mess and unfortuatly a lot of performers like to walk around on stage barefoot.
     
  10. midgetgreen11

    midgetgreen11 Active Member

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    i have the same problem... we have a dance class that dances barefoot every day during fifth period, even in the middle of fiddler on the roof when there were screws and splintered pieces of wood lying around.
     
  11. Radiant

    Radiant Active Member

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    We have American DJ short PAR 56 house lights dead hung, focused straight down, about 20 or 24 of them. About half of the original lamps, the ones included with the cans, were defective. The glass would separate from the reflector after heating up for an hour or two. Thus, all our house lights have safety screens.
     
  12. Charc

    Charc Well-Known Member

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    I've had a T3 blow during a show, and rain glass down... some of our cyc units have screens, not all. Unfortunately, some people like to think that the screen is where the gel goes...
     
  13. JD

    JD Well-Known Member

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    Seen plenty of the inner quartz envelopes blow but I have never seen a 64 outer glass shatter. That being said, there is no reason to believe the outside will not break. Glass is glass. Funny stuff and can break at any time for any reason. I think it is very wise to have screens in anything that is overhead. The same is true with leko lenses. Haven't seen any shatter (they are suppose to be heat treated but so are par bulbs, and they are glass. Before they came with screens, I used to put hardware wire (1/4 by 1/4) in the gel frames. Didn't seam to wreck the gels. Haven't seen any sold now without them.
     
  14. Les

    Les Well-Known Member

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    Yup while I we were hanging lights for Les Mis a few years ago we had some Altman Par 64's as worklights. We heard a loud POP and saw that one of the Par's right above our heads had blown and there were a few small pieces of glass on the floor. The rest had been held in by the safety screen. After we let it cool we brought it down and discovered that the lamp had cracked right in half. We're not talking lens separation, I mean a huge curvy crack right down the center of the lens and there was no longer anything holding it together.
     
  15. TimMiller

    TimMiller Well-Known Member

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    I have seen that happen, I have also seen the lamp crack into thirds.
     
  16. porkchop

    porkchop Well-Known Member

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    We had one earlier this year that split and more or less the whole outer piece of glass fell as a whole. During tech rehearsal, scary stuff, no one hurt thankfully.
     
  17. icewolf08

    icewolf08 CBMod CB Mods

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    Now to qualify what porkchop said. We had a PAR64 that decided that it no longer wanted to be a WFL, so it blew off the lens and made itself a VNSP. Made a loug bang like a stage gunshot. In fact we thought it was a gunshot because they were working with guns on stage. Then there was the falling lens which broke in 2 or 3 pieces when it hit the floor, which one of our ASMs decided should be picked up. We she learned quickly that it was very HOT. Well, we got up and replaced the lamp, and cleaned up the pieces, and went on with tech.
     
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  18. derekleffew

    derekleffew Resident Curmudgeon Senior Team Premium Member

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    I find it interesting that [user]JD[/user] and I, who have something like sixty years of experience with ParCans between us, have never seen a PAR64 lamp break without impact, yet many others have.

    [user]JD[/user], I guess we're just lucky old farts.:)
     
  19. ship

    ship Senior Team Emeritus Premium Member

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    Never seen a PAR can lamp explode but that don’t mean I won’t service a older can without requiring as a part of my work adding a safety screen. Take it or leave it just as asbestos don’t exist for fixture whips in what I get a hold of no matter if I service the gear in the end or not.

    About a month ago I was building some audience blinders for a rock tour, some sort of tentacle lights as they became referred to. Totally cool fixtures me taking some up to 8' long extensions of goose neck tubing, adding copper tubing sleeving to them than attaching some 12v/50w track light fixtures to the tips of them. Added a bit of wire rope safety cable that could pick up the slack in should they sag, and special wire that would fit within the gooseneck, plus cooling vents to the fixtures so as to make what was not designed to have a PAR 36 lamp at 650w/120v be okay with it. Very careful observation and laser temperature gauge study of how to modify the equipment.

    Anyway, at first I had to do some stainless steel window screening like filters at the front of the lamps so as to provide safety screens for them. This cut light output down by like 30%. Designer was not persay happy with this choice on my part but trusted in my necessity of adding the safety screen. Luckily or unluckily once prototype hit production the prototype fixture was not available sufficient to do the project by the time I had a go with it. I had to find another track lighting fixture similar but not as good and re-invent the wheel as it were in what I was going to do. IN part that was how to do the safety screen. In the meant time I also found out that a window screen physically touching the audience blinder lamp was perhaps a bad thing for that screen and lamp. The prototype fixture lamps physically melted around the screening in bonding to it and deforming about it with a bubble in the center. Not just one but three lamps were toasted in this way. Were it not for the screening that lamp will have gone bust in its outer form given the bubble of screen retaining heat and touching lamp.

    Anyway, overall point was be it a PAR 56 can still in our electronics repair department that I won’t touch until the client approves of the extra parts and time needed to add a safety screen to it, or a designer that based upon my requirement for a safety screen on a individual audience blinder lamp as part of the creation I’m making for him it is done. This safety screen is there no matter if it as initially accepted is a fine screen that reduces light output or as total re-design works as per a normal PAR safety screen in protecting against big shards of glass. The requirement is still there and I don’t work otherwise in walking away from a project where safety were not followed.

    A T-3 cyc light overhead as with a A-21 type cyc light with glass overhead is different than that of a PAR lamp overhead overall. Never seen a PAR lamp come down in pieces but am aware of this happening in a dangerous way before be it from PAR 38 to PAR 64 thus the safety screen. If the directions for the fixture and lamp in it recommend screening, that’s for a reason. Screen the sucker or pull it from service.

    Yep old timers etc. club before. Now we (or those old persay) lived thru stuff and want to leave the stage neater than we found it perhaps. Not a question of what you have seen before now, it's more the concept of what a 1# sheet of glass from like 20' could really do to someones head. No its not about the speed it or a particle attains, more about the momentium after it reaches that speed.
     
  20. Conner8809

    Conner8809 Member

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    When i was at a district competition watching one acts they had a lamp shatter and that was the coolest thing EVER. all you see is a big flash of light, SHATTTERR. And that is why you NEVER want to touch the lamp with your fingers. it makes them more suseptible to shatter. something about the oils...
     

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