I recently acquired this old book from 1975 called "Sisustamme valolla" (Decoration with light) which was written by Eino Lampi from Airams R&D. In that book there is a list of standart fluorescent lamp wattages and sizes. What troubles my mind is that there is listed a lamp that is 25W T12 with lenght of 970mm. I guess that modern version would be 23W T8 which has same lenght? I have never seen such lamp myself but was just wondering what kind of applications such lamps were used and is it a commond wattage in other parts of Europe?

Heres a picture of that list: http://www.whitenightcape.com/kuv/WP_20160116_10_09_48_Pro.jpg

33 inch T12 25 watt tube seemed once common tube in USA .

Not sure about this lamp. I recall seeing a 1080mm long 40w lamp specified on a Thorn EMI ballast from Britain (that came in a 38W 2D lantern)

These were the first fluorescent lamps which have been marketed here in Europe by Philips known as Philora TL100 with the lenght of 970mm, 25W and 100Deka Lumen.
These size was not that common. Mostly found in show cases and signs. The T12 25W tube was replaced later by the 23W T8 for energy savings. It has the same physical lenght as the 36/40W 1m which is rare as well.

These size was not that common. Mostly found in show cases and signs.

I think this size is used in older trams - with resistive ballasts, two in series, on 600VDC...

@funkybulb: 970mm is about 38 inches, which doesn't correspond to any North American lamp that I'm aware of.

These were the first fluorescent lamps which have been marketed here in Europe by Philips known as Philora TL100 with the lenght of 970mm, 25W and 100Deka Lumen.
These size was not that common. Mostly found in show cases and signs. The T12 25W tube was replaced later by the 23W T8 for energy savings. It has the same physical lenght as the 36/40W 1m which is rare as well.

Thanks for the info. I guess that it may have been some mistake to include that lamp for listing since it not really with common lamps.

There was also this other very interesting lamp called heijastinlamppu. It's standar shape incandescent lamp that is partially opaque. The top part of the lamp is clear. Idea seems to be that this lamp would be wide angle spotlight that also would shed some light for other directions aswell. There is crappy black and white picture of such lamp but otherwise I have never seen such lamp nor there is any mention about such lamp in Catalogs I have.

While a little bit of time passed since the last post but I have some info where such tubes are still present. 25W tubes in Central Europe can be associated with railways. When in 1950s fluorescent lighting first appeared in passenger cars and electric motor units (EMU), 25W tubes were first used, with 20W and 40W appearing later. Factories in GDR were first to produce rolling stock with such tubes and in Poland, Pafawag Wrocław soon followed. First EMU from Pafawag with such lighting system was EW55 which rolled from assembly line in 1958. It served as the basis for EN57 which was produced from 1961 to 1993. EN57 inherited technical solutions from its predecessor and during the course of production very little changes were made. The result is that in 1990s there were still made EMUs with archaic system of 25W tubes powered by a motor-alternator set while simultaneously made newer constructions were given up to date inverter technology designed to be used with 18W/20W and 36W/40W tubes. Many EN57 were since scrapped or heavily refurbished but there is still a great amount of 25W tubes to be seen around. Here are examples of such tubes: http://www.lighting-gallery.net/gallery/displayimage.php?album=230&pos=26&pid=121348
http://www.lighting-gallery.net/gallery/displayimage.php?album=230&pos=27&pid=121347
Apart from this EMU series from Poland I've seen such tubes in passenger cars from 1980s belonging to Czech Railways, made in GDR by Waggonbau Bautzen.