While what Medved says is true, and we can't stop the effects of supply and demand, coupled with the awkward lenght of 8 foot lamps, there are still areas in which they are the best option. Very large rooms with relatively low ceilings are better lit with 8 foot tubes as HID creates too much glare. The longer tubes make fewer ends, which increases efficacy. Large rooms with tall ceilings can sport HID lighting no problem, however. Unfortunately, supply and demand combined with government regulations on efficacy, as well as the current style, make the 8 foot lamp less profitable. In our money-oriented society, the least lucrative product is abandoned, no matter what quality or what advantages one may gain with it. If you really want 8 foot lamps for a long time, the only solution is to stock up while you can, and store them where the cat won't send them crashing to the ground while chasing someting ! 

While what Medved says is true, and we can't stop the effects of supply and demand, coupled with the awkward lenght of 8 foot lamps, there are still areas in which they are the best option. Very large rooms with relatively low ceilings are better lit with 8 foot tubes as HID creates too much glare. The longer tubes make fewer ends, which increases efficacy. Large rooms with tall ceilings can sport HID lighting no problem, however. Unfortunately, supply and demand combined with government regulations on efficacy, as well as the current style, make the 8 foot lamp less profitable. In our money-oriented society, the least lucrative product is abandoned, no matter what quality or what advantages one may gain with it. If you really want 8 foot lamps for a long time, the only solution is to stock up while you can, and store them where the cat won't send them crashing to the ground while chasing someting ! 

They're £20 each, up from £6 3 years ago...

The electrode related efficacy loss is not much dependent to number of ends, but to the overall arc voltage (higher arc voltage mean less relative losses on ~15V cathode fall). So for short, low voltage lamps it indeed correlate with the number of ends, once the lamp reach the maximum, longer lamps should maintain this value (otherwise they would have troubles with series choke, while transformers would have way higher losses). So even the 8' tubes have similar arc voltage to 4', so the electrode fall losses are about the same for 1x100W as for 2x58W lamps.
Second the lamp current has to be higher, what lead either to higher discharge current density, or to larger tube diameter. Both reduce the efficiency in generating the UV, or add losses on it's path to the tube surface (where is the phosphor).
These effect cause in fact the efficacy to lower compare to lower wattage lamps.
Of course, one higher power ballast would have lower losses then two lower power ballasts, but this is only about to compensate for the above.
Bottom line the efficacy of one 8' tube system is not higher then of multiple e.g. 5' ones.
Moreover in low bay installation higher amount of lower output fixtures mean more even light distribution, what mean lower total lumen requirement (so lower wattage) for given minimum illumination spec. Again, not favor for 8' tubes.

8' popularity (my guess) was based on the fact, then each fixture did cost about the same, not much depend of the size, what make fewer fixtures cheaper. But these days the production volume difference made the 5' or 4' fixtures way cheaper, so placing multiple of them instead of single 8' lead to the same installation cost - so this advantage of 8' is gone...

Quote from: DieselNut on June 11, 2011, 12:23:33 PM

I am surprised there has not been a T8 switchstart lamp introduced to directly replace the 8 foot European T12s like they have done with the 36 watt 4 foot and 58 watt 5 foot lamps.

So was I, I use a T12 8ft switchstart to light my room (Thorn) and it has been working for many years, but the EU are not going to introduce an alternative, so all 8ft T12s will have to go, I think  

@Jack Thorpe and Dieselnut: I also surprised. In the UK the krypton energy saving retrofit for the 8 footer 125W T12, is also a T12, but of 100W, as a result, it have lower intensity.
In James Hooker's site is written that the reason why the energy saving tube for the 8 footer 125W T12, is also a T12, is because at the time it was considered impractical to make such a long tube in T8 size glass owing to its fragility.
However as soon as i recognized that the US have 8 footer T8s, and they manages with them without problem, i don't know actually why currently there are no UK krypton energy saving 8 footer T8s (I think that non US made 8 footer tubes in Europe, are used only inside the UK, as they don't appears in the catalogs on the large european companies).

We have 8 foot T8s here in the USA, they are the single end slimlines. They are quite fragile, but they are still popular as lamp and ballast retrofits at least in the Southern California area.

Sylvania is introducing a line of triphosphor T12s that meet the new standards.

Does anyone have preliminary pricing or a release date for the new T12 triphosphors? I did see the new lamps listed in Sylvania's guide to replacement lamps but I don't know anything else about them.

Does anyone have preliminary pricing or a release date for the new T12 triphosphors? I did see the new lamps listed in Sylvania's guide to replacement lamps but I don't know anything else about them.

Does this apply in Europe? I like Sylvania

Does this apply in Europe? I like Sylvania

There are two Sylvaina: Osram Sylvania which is a US company and Harvells-Sylvania (SLI), which is an european company.
I think you means the european Sylvania.
You can see here how horrible are their Luxline Plus T5s: They start out very dim.

We have 8 foot T8s here in the USA, they are the single end slimlines. They are quite fragile, but they are still popular as lamp and ballast retrofits at least in the Southern California area.

Sylvania is introducing a line of triphosphor T12s that meet the new standards.

We also have 84 watt T8 HO tubes (with the RDC endcaps), but I have not had very good success out of them.  The 8 foot slimline T8s seem excellent.  I still prefer T12 in just about every application though.
That is awesome that Sylvania has new lamps that meet the new standards!!

So, what ARE the new bulbs? I can find vague references but not what they are ! Any GOOD links?


Powell

They are not in production yet. Look at this Web page and click on "Fluorescent Lamp Replacement Guide...". This document shows what lamps are banned in 2012 and what compatible replacement lamps are available now or will become available in 2012. Basically, CWX (halophosphate) lamps will still be available. Sylvania will then introduce some triphosphor lamps with a CRI in the 90s in time for the July 2012 ban. These are the lamps we are all waiting for that aren't yet available. I just hate to think what they will cost.

-Nelson

News posted today urges people to convert and makes it sound like it's time to throw away F96T12s entirely.

Now would seem like a good time to stock up on T12s & magnetic ballasts before they start getting really scarce & pricey. When you consider good (full-mercury) fluorescents should last decades in normal household use, we should be able to keep our T12 fixtures operational for a long time to come.

This article on the NEMA web site is quite interesting. It addresses the issues faced by residential consumers (which was my big concern, seeing as homeowners will be trying to put T8's in T12 fixtures) but also some things I didn't figure on, such as the availability of rare earth phosphors.

A thing was said about allowing only electronic ballasts for several types of lamps

Will it be hard to manufacture our own magnetic ballasts from standard electronic components (isolated or autotransformers, capacitors) or rewind microwave transformers etc ? (microwave transformers also have magnetic leak shunts, may be great for CWAs etc)

Does this ban affect the first generation of T5 lamps (F4T5 thru F13T5) ? I am wondering how long these lamps and their ballasts will be available.

All of the T5 efficiency standards I have seen only applied to the modern T5s.  Classic T5s would be exempt due to their shorter length.  The reason for the T5 standards would be to prevent cheaper, less efficient lamps, such as an F54T5/CW, from ever being put on the market.  Although I can't say it will never happen, it doesn't make sense for the government to ever ban the classic T5 lamps or T5 magnetic ballasts.  On account of their low wattage and low numbers, their impact on energy usage is negligible.  I should note that there are minimum efficiency standards for certain applications where smaller fluorescent lamps may be used, such as exit signs.