Melting Fluorescent Tube Covers

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sfav8r

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San Francisco Bay Area
The picture below pretty much says it all. This installation has 10 T-12s, each of which has a colored sleeve over it. I was actually there for another problem, but noticed this. As I checked the other lights, they all were starting to melt, so I removed them all.

These seem to made for this application, but the fixtures are installed into an arch that limits the air-flow compared to a free-standing fixture.

Has anyone else had problems or experience with these sleves? Do they make different temperature ratings? Are ther other options where colling is an issue?

Inquiring minds want to know.

Thanks
 
I've serviced a great many fixtures that were sleeved with gold tubes (UV filtering) for conventional prepress operations, and one's with red sleeves for photographic development operations. I have never seen the type of failure illustrated in your picture. Anecdotally, I can say that fluorescent tubes do get hotter near the ends (as compared to other spots on the lamp), so if this type of failure was to occur you'd expect it in the exact spot on your pictures.
 
I've seen many failures exactly like this. One mill I work in uses many of these tube covers, mainly on 8 foot fixtures, and I have found the ends of tube covers that are melted in a similar manner. In my humble opinion, these tubes covers are one of the worst things ever made because they hold the heat, the covers are not actually long enough for the tube meaning the end caps don't proper fit on there to totally encapsulate the tube, and in many instances, the end cap causes the single pin at the end of the tube not properly fit into the lamp socket causing arcing and socket failures. It is more expensive, but I have used the tubes that actually have a plastic covering factory applied (gold tubes) and so far have not seen any problems with them.
 
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Before ever seeing your picture, my guess is that they were melting on the ends. I have seen it and I do know that the tubes will get hotter on the ends, but if these covers are made for this they shouldn't be melting.
 
I have had the exact thing happen to a number of H.O. fixtures we installed in one of our warehouses. We ended up just not using the covers after relamping the fixtures.

As a side note, unless there was some kind of error in the pdf translation, I am really shocked at the spelling / spacing errors on Rosco's spec sheet for the tube covers. It looks very unprofessional for a company's literature, and just kind of grabs you as you are reading it.
 
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