Original argon T12 tubes weren't efficient enough to satisfy these greedy people apparently . So alternatives were made. But some are confusing, and I have some questions. Here we go:

---

1) 48T12 40W -> 34W Conversion:
Lamps fitting the typical 48T12 dimensions of a 40W lamp that only use 34W exist. I have certainly burned through a few in my life. It is my understanding that they are filled with a little bit of krypton among the normal argon to make their running voltage lower. This also has the unintended effect of making their striking voltage higher. Is this correct? I sometimes hear people have trouble running these, what ballasts are these suitable for?

2) T12 -> T8:
On Lamptech, I can't tell whether is it implied that krypton T8 lamps were meant to be retrofits for T12 lamps. In my calculations (admittedly flawed), running a 48" F32T8 lamp on a 48" F40T12 ballast would result in a little less than 400mA instead of the necessary ~217mA. And I know that different ballasts exist for both types of lamps, so they are likely not compatible. Were these ever supposed to be retrofits? Why couldn't they be made to be retrofits for T12s?

3) T12 -> T10:
I hear of these Japanese T10 retrofit lamps that are T10 diameter. How do they compare to the T12 Supersaver-style retrofits? Why didn't they catch on much over here?

4) Other technologies:
Is there anything I am missing? Did other countries or companies have other more interesting advancements in retrofit fluorescent lamps?

---

Thanks!

This is an American point. Elsewhere in the world, T8 36W is equivalent to T12 40W. Also to large PL-L 36W CFLs. And freely interchangeable except when used on rapid-start, which mostly died out at about ~1980s.

The same goes to rare T10 tubes.

@RRK
So do European F36T12s have different specs than American ones? If so, what are they, and why couldn't American ones be like that?

No such thing as F36T12 here. Typo?

Here, F36T8 = F40T12 = 36W PL-L = 40W T9 circline (1200mm, ~4ft)

And, F18T8 = F20T12 = 18W PL-L (600mm, 2ft)

And F58T8 = F65T12

I am using American nomenclature FxTy, x=power, y=diameter, but local lamps are not always marked as such.

Actually, a big screwup of traditional American fluorescent numbering is double meaning of FxTy. Where x may mean both tube wattage or tube length in inches, depending probably on some historical reasons. Lamps elsewhere follow somewhat more sane numbering, like Sylvania marks their Euro 58W T8 tube as F58W/827, and Osram marks F8T5 as L 8W-41/827

Attempts to correct that mess as by renaming F40T12 tubes known for almost a century to 40W/48T12 leads to even more confusion...

@RRK
Right, my bad, I messed up a bunch of wording lol. Take two:

So American 48" T8s are called F32T8s. These are what you see (or used to see) in practically every single commercial building ever. Probably the most popular tube in the US (if I were to guess). But in homes, (in shop/garage lighting), F40T12s or their physically identical energy saving equivalent F34T12s are what you will see. But these two popular tubes with identical basing dimensions are not interchangeable.

I am just realizing now that European 48" T8s are called F36T8s. Which is a different name/wattage. And these F36T8s are compatible with F40T12s, unlike American F32T8s which are not even close to being compatible with F40T12s.

My question is why does the European market get a nice energy saving T8 retrofit for F40T12, while we don't? Our F32T8s need completely different ballasts, while European F36T8s seem to just be a drop-in replacement. Of course here I am just referencing 48" tubes, but this also applies for other lengths.

What are the specs of these European F36T8s of other T8 drop-ins, and why couldn't the US get any of them (or make equivalents)?

And I totally get your complaint about the US fluorescent tube naming system, it is completely ridiculous. I just need to know what is being referred to, watts or inches. I will probably make another column in my datasheet for the tubes common names.

I believe the usage of the length in the model nomenclature came about in the late 1940s/early 1950s when slimline lamps were introduced. I believe during the early days of slimlines, you were able to drive a certain length lamp with different drive currents so the wattage will vary and I suspect that was the main reason why they chose using the length instead. Generally for North American lamps, FXX where XX refers to wattage is for bi-pin lamps. Lamps that use plunger based lampholders (RDC, FA8) generally have XX referring to the nominal length in inches.

I believe the F36T8 lamps aren't compatible with the more common rapid start ballasts used for F40T12 lamps here. They are however compatible with certain types of preheat ballasts. I believe lagging preheat ballasts (eg LPF single lamp F40 preheat, the lag side on a F40 Tulamp circuit) are compatible and the lamps aren't fully compatible with the leading side on the Tulamp ballasts. @WorldwideHIDCollectorUSA has done some testing on that and might be able to elaborate.

The niche compatibility for the F36T8 and the prevalence of incompatible rapid start systems probably led to the development of the rapid start only F34T12 lamp as the energy saving drop in replacement for T12. In parallel to that, a new 4ft T8 lamp with a newly designed ballast, the F32T8 was developed for applications where absolute energy savings was the goal and for new installations a sort of clean slate design were compatibility with existing equipment was dropped..

Yes, very much likely, the reason why no direct T8 substitute for F40T12 on American market may be still a significant proliferation of magnetic rapid start ballasts, obviously not very compatible with krypton filled tubes. I think Europe and neighbors mostly got rid of rapid start ballasts around early 80's migrating to preheat (for cheap) and electronic ballasts. Both won't have problems starting Kr filled T8's.

Ahh I see, a ballasting problem. Magnetic RS ballasts were/are extremely common, practically all 4ft fixtures had them at one point, and many still do today. Cause the only way we could get preheat with our longer tubes on 120V was to have an HX or CWA-style autotransformer preheat ballast, and at that point you are only a couple more coils off from RS so just go all the way.

Why are RS ballasts bad for these retrofit lamps? I am guessing it is their CWA-like characteristics? Though some of the cheaper ones (like my Advance Benchlite) were pretty much just HX.