T-8's - FAQlet
> From: crom at cris_com (Crom)
> I just saw a recent posting to the APD which suggested that there was
> more that one kind of t-8 bulb (?). It said something to the effect
> that the poster wasn't talking about the bulbs often found in 30"
> lengths labeled as T-8s. Isn't a T-8 bulb just a bulb with a 1"
> diameter, whereas a T-12 has a 1-1/2" diameter?!?
Sigh. Once more, what is rapidly becoming a FAQ:
Technically, T-8 means 1" diameter bulb, and T-12 means 1.5".
Traditional Normal Output (NO) bulbs are manufactured mostly in T-12, with
T-8 sizes being used for the 20" and 36" sizes.
HOWEVER, often in the APD, when we are refering to T-8's, we are talking
about a TYPE of fluorescent light, not a size. Specifically, T-8 is used
to refer to high-efficiency Instant-Start bulbs. These units all require
a special electronic ballast, and have different wattages. 24" = 17 watts
(FO17), 48" = 32 watts (FO32). And they are all made in T-8 size, even
for 24" and 48" tubes. These bulbs are mostly used in commercial
applications such as newer office buildings, because they can cut an
electric bill in half for the same light output. They are hard to find in
the usual consumer outlets (like hardware stores), though I've seen
ballasts and tubes at Home Depot. For this reason, you have to go to a
local commercial lighting supplier or catalog, like Grainger. Once you've
found a source, you'll be pleasantly surprised at the inexpensiveness...
4-tube ballasts are $25. 5000K bulbs cost $5-10.
Other misc. tidbits picked up about T-8's:
* You can cram more of them in your hood.
* Because of their small diameter, more light reflects off the fixture,
into the tank (as opposed to being blocked by the tube).
* Their lifetime is supposed to be greater than traditional NO's.
Erik D. Olson amazingly, at home
eriko at wrq_com