24/7 HID Lights

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scnkapc

scnkapc

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It has been brought to my attention that HID lighting manufactures are requiring that if their lights are to be install in such a way that they are required to be on for 24/7 that they need to be shut off for 15min every 24 hours. This mainly has to due with factory lighting. There have been reports of HID lamps exploding over work areas and injuring employees.

Is there a code reference to this effect or is it only a manufactures requirement?
 
Re: 24/7 HID Lights

scnkapc said:
Is there a code reference to this effect or is it only a manufactures requirement?
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There is no NEC requirement for that and I believe it is a manufacture recommendation not a requirement.
 
This mainly pertains to metal halide lamps, which will explode if they are operated beyond their rated life.

There have been reports of HID lamps exploding over work areas and injuring employees.
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See 410.73(F)(5).
 
Actually the lamps are most likely to fail violently on a cold start-up. So 15 minutes allows them to cool. This has been a situation with these lamps for more than 15years. Most of the lamp manufacturers have technical papers on this problem.
 
I know of a company that runs 24/7 that doesn't shut down lights at all. There have been a couple of light that have broken but know one knew what happen to cause the break. This company runs T-5 lights on the other side of their floor and the lighting company told them to shut down them for 15 min. each week. Haven't seen any problems yet.
Jim
 
We have 5000 MH150 med base lamps in Holophane fixtures. All are on 24/7. When these fixtures were first installed (1996) we were told by the fixture manufacturer and the lamp manufacturer that we should shut them down daily. They would not accept liability for any accidents or assaults etc that may occur during the lights out time. Nor would they be willing to pay for our electricians time to turn the lights off and on.

We of course do not turn them off. Since 1996 we have had maybe 100 lamps explode. Not many considering the tens of thousands we have installed over the years.

H.L.
"you can't fire me, I ain't doin nothin"
 
Jim,
Actually the lamps are most likely to fail violently on a cold start-up.
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I don't think so....the exploding failure is when they are left on 24/7. About 3 to 5% of these lamps will fail violently at the end of the lamp life if left on 24/7, but if you turn them off for at least 15 minutes each week, the lamp at the end of its life will just fail to start and not explode.

The internal arc tube of a metal halide lamp operates at 1600-2100?F and an internal pressure of 75 to 450PSI. When that lamp fails violently, the hot glass from the arc tube can injure people and start fires.

Don
 
LarryFine said:
peter d said:
See 410.73(F)(5).
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I did. It says:
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ooops, did I quote the wrong code section? Darned typing errors... :roll:

At any rate, there is a code section in the '05 that addresses this. It requires O rated lamps for an open fixture.

But since I don't have my book right now I can't tell you what it is. :D
 
Peter, you did good.

410.73(F)(5)

(5) Metal Halide Lamp Containment Luminaires (fixtures) that use a metal halide lamp other than a thick-glass parabolic reflector lamp (PAR) shall be provided with a containment barrier that encloses the lamp, or shall be provided with a physical means that only allows the use of a lamp that is Type O.
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Roger
 
Don,

You are correct about the failure occuring at end of life. But it is detected at start up.
My comment was really supposed to address the reason for the 15 minute period. The cool down period causes the lamp to try to restart, which it will not do at end of life.
 
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