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Old 16th Jan 2019, 12:15 am   #56
1100 man
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Join Date: Apr 2016
Location: Ventnor, Isle of Wight, & Great Dunmow, Essex, UK.
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Default Re: The demise of the fluorescent tube

Well, this thread has certainly generated some interesting comments, especially about the negative aspects of fluorescent tubes!
I've certainly never considered flicker but it seems to be a real problem for quite a few people. I certainly can't perceive flicker:- my brain processes information far too slowly for that! Anything that turns on and off 50 times a second, it just considers as 'on'!

The question of colour temperature is also interesting. For me, 4000K is as cool as I feel comfortable with. I find being in a room lit with 6000k light really horrible. I've read that sufferers of SAD need 6000K+ light, but to me it's just chill and depressing.
It's interesting that when LED lights first appeared, they were very cool white. Most people hated them and manufacturers rapidly developed warm white ones. Currently, for domestic lighting, warm white versions seem easier to obtain that cool white.

'Daylight' fluorescent tubes have always been available but were never popular for general use- people just didn't like them which is why 3500K became the standard white for years!

I agree that the whole CFL thing was utterly horrible. We were forced into them on the basis of energy efficiency, but I'm sure if you take the manufacturing costs, toxic materials, almost universal disposal into landfill and often very short lifespan into account, then we would have been much better sticking to incandescent until LED's came along!

When I started this thread, I was really considering commercial rather than domestic installations. Fluorescent has probably never been ideal for domestic environments and LED's can offer much better alternatives.

However, I still maintain that the twin 6 foot fitting running with a high frequency (electronic) ballast fitted with the latest generation of tri-phosphor tubes is a very fine thing!

There are very low losses from electronic ballasts:- they run pretty cool as opposed to iron ones. 50Hz flicker should be eliminated. A 70W tube is rated at 6300 lumen when new, which will stabilise at 6000 lumens once it has run for 1000 hours or so. So a twin fitting is 12,000 lumens. LED's appear to be more efficient, but only because they are directional. However, the multi- directional aspect of fluorescent, means the light is reflected from other surfaces and so tends to reduce shadows. By comparison, a 6000 lumen LED fitting is rated at 60W, so hardly a step change in efficiency!

In 2003, I installed about 30 6' twin high frequency fittings in a factory. They were actually made by 'Fitzgerald' and were nice units and well made. They had proper end caps rather than the 'twist the whole tube' type. They have been great and lamp life has been very good. They are now starting to have ballast failures. They have 'Philips' ballasts which suffer from dry joints (shades of the G11) on the input choke which causes a PCB burn up. However, I calculate that in that time they have done 32,000 hours of use!!
As electronic ballasts are readily available and a 'standard' item, I can just change them for new ones. That certainly won't be the case with LED fittings- the whole thing will need to be changed.
Interestingly, I've just changed the tubes in one of these fittings that was in an inaccessible location. They were the original 'Fitzgerald' branded tubes and were still working, although rather dim after 32,000 hours!!

The 8' tube was really good when it was in it's original 125W format. After it was down rated to 100W, it was always dull and gloomy. I've still got a couple of 125W twin units in my workshop and they give very good light.

I'm certainly not saying LED is a bad thing and obviously it will be the future, but I've spent my whole life loving fluorescent so you can hardly expect me to transfer my allegiance overnight!

All the best
Nick
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