Some Qs about lights

[Allen_1971]

I've been thinking a bit about the efficiency, and I was wondering, what are the typical levels of lm/watt achieved by the various types of lighting?

Also, I'm a bit confused... can a T-8 tube be used in a T-12 fixture? Would the ballast required to drive it be the same or is there some difference?

[vinz]

lm = lumens?

[Allen_1971]

ah yes... lm = lumens... I was wondering how efficient our lights were at converting power to light.

[tawauboy]

some figures for you to ponder.
taken from here
t12 diameter is 2.5", t8 diameter is 1".

based on 4' tubes,
t12 (34w) is rated 2800 lumens but actual is 2370.
t8 (32w) is rated 2800 lumens but actual is 2510.

t12 needs 41watts for 34w of light, efficiency = 82%
t8 needs 31watts for 32w of light, efficiency = 103% ???

it seems that t8 cannot be used in t12 fixture due to t8 requiring eballast while t12 uses magnetic ballast.

[Allen_1971]

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On 11/27/2002 1:29:23 PM
t12 diameter is 2.5", t8 diameter is 1".

it seems that t8 cannot be used in t12 fixture due to t8 requiring eballast while t12 uses magnetic ballast.
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Interesting figures, though the T12 is 1.5" not 2.5". Also If my lighting happens to use e-ballast, then I can use T-8 right?

[tawauboy]

opps!
typo error, t12 is 1.5".
if you are using ebalast then you can use t8.