I’ve been using CFL bulbs in the ceiling light fixtures of my own home for a few years now and I’m noticing some discoloration and degradation of the fixture wire insulation, white paint on the canopies and the plastic lamp sockets. I’m guessing this is due to the heat and UV light from the fluorescent bulbs.
Years back, I remember a similar type of yellowing and degradation of the white plastic housings, wire insulation and internal components of incandescent exit lighting that were retrofitted with fluorescent lamp kits.
Have you seen this type of thing occurring in incandescent fixtures using CFL bulbs or that have been retrofitted with fluorescent lamp kits?
I’m wondering how this will play out if and when the proposed incandescent bulb ban takes place. It seems you would have no option but to use CFL bulbs in fixtures that were never designed, tested or listed for their use, which could result in various forms of deterioration on a large scale that I’ve been noticing.
I find it interesting that as electricians, we have to go to great lengths to follow UL listings and manufacturer’s instructions, for fear of liability, but Congress seems poised to pass a law which mandates the complete dismissal of these.
Where is the heat? That is where the problems will be, The heat in flourescent luminaires moves from the lamps to the sockets and the ballast.
I am seeing more and more problems with ballasts causing heating problems including the complete decomposition of plastic fixture boxes.
An incandescent bulb is hot above the base. IE you unscrew a hot bulb and you can often hold the base but the glass burns your fingers. CFL are the oposite as are PL lamps which also have a heat producing ballast which transmits its heat into the outlet box. Lots of the new energy efficient luminaires are reworked incandescent luminaires.
I'll disagree a wee bit.
It's not heat at all ... after all, there is no part of a CFL that gets anywhere near as hot as an incandescent.
UV from the bulb is another issue. Ever wonder why troffer lenses get so brittle? Or why the nice ones are so 'rubbery' and cost so much more than the box-store specials? It's all about the UV.
The UV component of fluorescent lighting plays pure hell with plastics - and is likely part of the reason some folks just don't like fluorescents.
Reno, I'll disagree with you.
The UV created by the flourescent bulb is used to excite the phosphor inside the bulb. I would expect that little to no UV escapes the tube under normal operation. Plus glass is not transparent to UV. However, quartz is transparent to UV. That is why quartz halogen bulbs have to have a glass filter to block the UV. That is also why metal vapor lamps have a separate glass bulb around the arc bulb, to block UV.
I expecxt the reason why box store fixtures have such crappy diffusers are because it is cheaper.
Larry, I agree with you to a point ... yet ....
Even quality fixtures used in commercial applications have their diffusers yellow and become brittle with time.
Drapes and upholstery still fade in the sun, even when there's a double-pane window in the path.
Isuppose we can compare lighting to sex: both intensity and frequency matter!
Reno
I agree the ballast isn't likely as hot as a bulb but the ballast is sinked to the base of a luminaire and if the luminaire is surface mounted right on the box then the box becomes part of that heat sink. Some of the luminaires i am thinking of have glass lenses and the ballasts are not visible to the radiated light.
CFL have the ballast built into the base and scerw into normal 660 watt lamb bases. If a 100 wat bulb was installed the heat is produced above the base in the filament and yes it is damn hot. The bulb base is relatively cool and depending on how long the luminaire has bee on will get close to the internal ambient or the luminaire.
Replace that 100 watt bulb with a 27 watt CFL and the interior of the luminaire won't get anywhere near as hot except that the base gets hottest and it gets hot much sooner than the base of the incandescent bulb. Like I said it is pretty easy to hold a CFL by the glass even when it has been on for a long time. The base is hot to the touch and very hard to hold if it has been on for a while.
Refering to the 'screw-in' CFL bulbs, nobody has mentioned the orientation of the base within the luminaire.
Years back, Phillips came out with the 'Earth Light' CFL, and the directions on that box read....burn base DOWN only. The recent 13 watt that was a give-away at the mall, does not seem to have any direct guidance (directions) on compatability.
The real fine print, on the inside of the box, in three languages mentions 'use in recessed fixtures will result in shorter bulb life'. Further down, 'base of unit is hot after operation'.
I saw quite a few of the early Earth lights' that suffered from discoloration of the base containing the ballast, and some with what appeared to be ballast failure and very dark brown plastic bases.
A side note on this subject was a discussion with an Architect relating to CFL fixtures. He spec'd CFL recess, but no brand name or model. The Ec installed regular H-7 cans with screw in CFL bulbs! I'm still waiting for a response from the H-7 mfg if this could be a listing issue. BTW, open trims I assume. This could just be an Arch/EC issue depending on the mfg info.
As KJay was alluding to, there may be an awful lot of degraded sockets from the CFLs in the future.
It's not a listing issue.
UL has issued a blanket statement, published in IAEI news, that pretty much says 'if it fits, it's fine.' The only qualifiers relate to markings on the bulb - not the fixture.
The UV created by the flourescent bulb is used to excite the phosphor inside the bulb. I would expect that little to no UV escapes the tube under normal operation. Plus glass is not transparent to UV. However, quartz is transparent to UV. That is why quartz halogen bulbs have to have a glass filter to block the UV. That is also why metal vapor lamps have a separate glass bulb around the arc bulb, to block UV.
Regular glass is partially transparent to UV, and I wouldn't count on a 100% efficient phosphor and completely uniform coating along the inside of the envelope. Difference in heat can easily be measured with an IR thermometer, and the inherent increased efficiency of the fluorescent system (lower wattage, more energy converted into light) logically suggests a lower heat output. What other factor, besides UV, would break down the plastic so much? If you have a look at some exit signs, the fluorescent ones fall apart much quicker than incandescent or UV... I've broken a couple of covers on fluorescent ones because the plastic became so brittle from burning 24/7.
I'd like to see your source for claiming that quartz-halogen bulbs MUST have a glass filter. Other than PAR and sealed MR-type lamps, a lot of QH lamps have no such filter. Especially with MR16s and PARs, I think the reason for having a sealed unit is more for protection of the fragile envelope from moisture and debris, and to contain the fragments if/when the lamp blows.
Depending on the type of enclosed fixture we're taking about, have a look at LED PAR/MR lamps. While LEDs probably won't replace our general workhorse bulb, they are great for directional lighting--and the latest batch have color temperatures in the range of halogen.
Noderaser, I do not have a chapter and verse citation for the need for glass.
A quick search found this document from NEMA.
Quartz halogen bulb safety
We did change the design of MH fixtures over this issue. Either the fixture is enclosed - or the bulb needs additional protection built-in. This is 'enforced' by having slightly different bases on the bulbs. A 'protected' bulb will fit in any mogul socket, but the sockets in open fixtures will not allow the unprotected bulbs to fully seat.
This all came about because a bunch of teachers at a conference got severe sunburn- caused by the bulb in the fixture over them having lost part of the glass envelope.
HID bulbs - unlike ordinary incandescents - do not require a vacuum to operate. I replaced one perfectly operating mercury vapor fixture that had been lighting up just fine for at least two years- even though the outer bulb was completely absent.
The finer points of HID design aside .... and getting back to CFL's ... I admit that the yellowing and brittleness I ascribe to UV is only a theory of mine. I am not able to actually go out and make measurements.
What also seems clear is that there is no point on any CFL that gets nearly as hot as incandescent it is intended to replace. That, I suspect, is why UL is so comfortable in telling you it's OK to use these bulbe- even though the fixtures were never evaluated for use with CFL's.
Doesn't really specify strongly either way; some excerpts are that UV is less than 1% of transmission, and that shielding is not required/recommended for all QH products. The ones that immediately came to mind are MR16s, although they are available in both sealed and unsealed (exposed envelope) versions.
Having witnessed what happens when a QH lamp explodes, I'd prefer there be at least something there for protection. Some fixtures use a screen instead of glass to prevent shards of 1200F glass from flying all over. Of course, aside from the MR16s in my kitchen most of the QH lamps I use are minimum 500W, up to 2kW. A 25W MR16 may not be as susceptible to a violent explosion like the big boys.
Also, the sealed ones are much easier to replace up high with the suction-cup re-lamping pole :P
It's not a listing issue.
UL has issued a blanket statement, published in IAEI news, that pretty much says 'if it fits, it's fine.' The only qualifiers relate to markings on the bulb - not the fixture.
Reno, I read that article, but I'm wondering if that actually qualifies as an offical statement from UL, since it's not on an offical letterhead or other type of offical UL document. Do you know if there is any other documentation available from UL on this subject?
Thanks.
No, a press release is not an official document. If you want / need one of those, your area is sure to have a local UL rep who can get you one!
Let's get real, though. The PIO at UL isn't going to say 'good morning' without official sanction.
It's not a listing issue.
UL has issued a blanket statement, published in IAEI news, that pretty much says 'if it fits, it's fine.' The only qualifiers relate to markings on the bulb - not the fixture.
Reno,
i was wondering if there's any access to this UL statement ?
~S~
That article does not address the "reflector" issue.
These CFLs, even most of the ones that look like "R" bulbs, still have the ballast above the reflector so the heat is not radiated out of the can.
I know a CFL 65w equivalent R bulb died an early death in an H-101 in my yard. The ballast was chocolate colored.
Just a reminder that the presence of a UL lable, and use as intended, does not suggest that the product is not a complete piece of junk.
I also suspect that the UL response will be applicable with LED's, or whatever the next gee-whiz replacement for the ordinary light bulb is created.
Reno:
I just read the article thru your link. Interesting that they say a fluor. lamp emits less heat than an incandescent. NO mention of that pesky self-contained ballast.
There also is no mention of the luminaire (fixture) being 'approved/listed' for CFL self contained devices.
Alas, reading kinda between the lines the jist of reading the CFL 'instructions' is mentioned.
I think one thing to consider about CFLs is the quality of manufacturing; they're not just a filament in a glass bulb--they contain electronic ballasts with capacitors, PCBs and the like. Pick your type of comparison; Harbor Freight vs. DeWalt, whatever. Pressure to keep these cheap as a reasonable replacement for $0.25 A19 incandescents can't mean there is a lot of time spent on high grade engineering and quality assurance. Aside from the manufacturing quality issue, there are also simply many more parts that can fail. I've had some CFLs that don't last as long as a 2000-hour incandescent. I also have a pair of "Designer's Edge" CFLs that I bought around 2000 that are still going strong.
Consumer Reports did an article about CFLs a couple of months ago (October 2010, p26-28) and included some reliability tests. Surprisingly, the "EcoSmart" brand sold at Home Depot had the best ratings for indoor lights; GE and Philips did okay-ish. Their test list wasn't very long, but it gives you a good idea of the range of quality.
Re: fluorescents and UV: one particular range of 1980s Siemens light swtiches is extremely prone to yellowing if exposed to any direct sunlight (sold in Austria and Germany in the mid- to late 80s and early 90s I think). I know some in an English basement that never get any sun and those still look like new. Now there is one university restroom that doesn't have a window, not even the hallway in front of the door. So the only light in there is a CFL in a recessed fixture. The light switches in the stalls (pretty solid, there are tiled drywall stalls floor to ceiling) are as yellow as they ever get. So yes, apparently fluorescents do emit a considerable amount of UV.
Evidently I am wrong. Not a problem.
I have been wrong before and I expect to continue my imperfect record.
I sit corrected. Thank you to all who brought this to my attention.
Larry C
as an aside here, there seems to be a great concern about UV and electrical equipment.....
errrrumhhh.....
what about us?
~S~
If you go outside or live in a house with windows, the big light source in the sky will give you more UV than any man-made source... At least, not any that aren't made specifically to produce UV.
Re: The light switches in the stalls (pretty solid, there are tiled drywall stalls floor to ceiling) are as yellow as they ever get. So yes, apparently fluorescents do emit a considerable amount of UV.
Let's hope they kill all the bacteria in there too then!
Joe