Dangers of HID Lamps

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tom baker

tom baker

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The 2005 NEC in section 410 (F) (5) has a new requirement for HID lamps, other than a thick glass PAR type, to have a barrier that encloses the lamp, or only allow a Type 0 lamp.

A type O lamp has a longer neck, if a non type O lamp is screwed into the socket it won't make contact.

The reason this change was submitted is if an HID lamp is left on 24x7, the HID lamp will not reach its end of life condition where is normally goes out, and the lamp will explode. Several fires have been attritubed to this.

This commerical garage had HID lighting that is on 24 x 7:

One of the HID Lamps exploded:

If you have HID lighting that is on 24x7, you can turn off the luminaires 15 minutes a week, this will allow the lamp to cool off, and when it reaches end of life it will go out and not explode.
 
I have been informed by our company that HID lighting - temp lighting in our case , must be monitered because if the outer shell is broken the lamp can still burn and has in fact given people sunburns when working beneath
 
The problem with violent end of life lamp failure only happens with metal halide lamps. This is not a new issue, the lamp package has been marked to indicate this hazard for over 15 years. Before the 2005 code rule in 410.73(F), the recommendation was to turn the lamps off for at least 15 minutes once a week. This would prevent the violent failure that occurs in a small percentage of lamps that are on 24/7. I worked on a couple of projects where 7 day time clocks and lighting contactors were used to provide 15 minutes of down time per week.
Don
 
Interesting, thanks Don. I don't do much HID work and wasn't aware it was marked on the lamp package. This lamp failure will be part of the justification to retrofit the HID with T-5. The T-5 can be switched on and off by the user with no warm up.
 
tom baker said:
Interesting, thanks Don. I don't do much HID work and wasn't aware it was marked on the lamp package. This lamp failure will be part of the justification to retrofit the HID with T-5. The T-5 can be switched on and off by the user with no warm up.
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Who's money are you spending:smile:
 
tom baker said:
Interesting, thanks Don. I don't do much HID work and wasn't aware it was marked on the lamp package. This lamp failure will be part of the justification to retrofit the HID with T-5. The T-5 can be switched on and off by the user with no warm up.
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Tom, I know that some of the companies that do the retrofits are reconsidering the use of the t5 bulbs and actually using the t8's instead. A plant I work at just did a complete retrofit along with replacement of the old MH fixtures with new fixtures using t8's with the 5000K color rendering and high output ballasts. The light output and color is really good and overall the cost was much cheaper than going the route with the t5's.
 
Any idea on the rate of these type of failures?
I have worked under these types of lights for a lot years now. I have only seen it happen twice, that I can recall.
The facility I am in now, has 200 of these lights and for the first 5 years after they were installed, they were never turned off, except for the occasional power failure, due to weather. None of these light have exploded. They get turned off now to save power during the weekends, when the plant is empty.

They have the clear lens enclosing them, so if it does happen, it is contained.

Just wondering if it is a common occurance.
 
FNCnca said:
Any idea on the rate of these type of failures?
I have worked under these types of lights for a lot years now. I have only seen it happen twice, that I can recall.
The facility I am in now, has 200 of these lights and for the first 5 years after they were installed, they were never turned off, except for the occasional power failure, due to weather. None of these light have exploded. They get turned off now to save power during the weekends, when the plant is empty.

They have the clear lens enclosing them, so if it does happen, it is contained.

Just wondering if it is a common occurance.
Click to expand...

Not sure about the frequency of these types of failures, but have you ever heard one when it blows a hole in the bulb? Sounds like a shot, a sure attention getter.
 
Bea said:
Who's money are you spending:smile:
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Our POCO has a rebate program to replace HID with T-5s. Even with out the rebate it has a good payback. With the rebate is almost no cost, assuming the HID is on 24X7
 
racerdave3 said:
Not sure about the frequency of these types of failures, but have you ever heard one when it blows a hole in the bulb? Sounds like a shot, a sure attention getter.
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Turning off on the weekend will prevent the lamp exploding
 
I was just kidding about the cost but the difference in design is the center pin on the base lamp and the socket center piont is reset so that it will not make contact with other than O lamps
 
The failure rate is only a 1% or 2. The problem is that the arc tube inside may be operating at 900?C or more and when it scatters hot fragrements around there may be injuries or fires.
Don
 
tom baker said:
Turning off on the weekend will prevent the lamp exploding
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Not always true. The plant that I was refering to for the better part of the year worked 5-6 days a week and was almost always closed on Sundays. So the fixtures had plenty of downtime. I'm sure that this schedule greatly reduced the number of failures, but lamp failures like this can occur even if the lamps have been cycled.
 
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