# Converting T12 - T8.



## MDShunk (Jan 7, 2007)

I know you're just an apprentice, but for conversations's sake, I often find it just as cheap to change the whole fixture. Especially if they have outdated prismatics, and I upgrade them to parabolics. It's a remarkable change.


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## Electric_Light (Apr 6, 2010)

The efficiency of the fixture is just as important. Yellowed lenses are usually permanent and it severely compromises fixture efficiency. 

They have retrofit "kits" that use existing chassis, but when you consider the time to do all those, yeah, its often more economical to replace the entire fixture. 

Depending on the design, fixture efficiency can vary from ~50% to over 90%. 

When you change out the fixture with better utilization factor, you can reduce the total lamp output and still maintain the same FC. If you were to go from 60% fixture to 80% fixture, you can reduce the lamp lumens to about 2/3 and luminaire output would be about the same.


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## B4T (Feb 10, 2009)

MDShunk said:


> I know you're just an apprentice, but for conversations's sake, I often find it just as cheap to change the whole fixture. Especially if they have outdated prismatics, and I upgrade them to *parabolics*. It's a remarkable change.


What does that look like.. I have seen some guys use the "egg crate" square pattern that has a chrome finish on it..


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## kevmanTA (Jul 20, 2010)

I only retrofit anything that looks too expensive or heavy to remove..
Most people won't do it unless more than half are already burnt out.


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## electricalwiz (Mar 12, 2011)

I agree the parabolic lens is way better, but a much harder sell when they have say 5 ballast out of a hundred bad. I just been changing the T12 to T8. 
It makes for alot of service calls


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## Electric_Light (Apr 6, 2010)

Recessed parabolic fixtures offer excellent utilization factor, although they do have an issue with "cave effect"

http://energycenter.org/uploads/case_suspendedID.pdf

In offices, we use computers. Back when T12 lensed troffers were installed originally in the 70s and 80s, predominantly computer environment wasn't in consideration. 

This is purely personal preference, but I like 5000K lamps for computer task. I find that going back and forth between looking around, looking at screen, paperwork, I find it visually pleasing.

When you have warm lights, paper looks yellow in 3,000K lighting after you've been looking at your monitor. When you look back at monitor, it looks blue.

Example of parabolic fixture:
http://www.lithonia.com/ES8/prodinfo.html


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## kaboler (Dec 1, 2010)

MDShunk said:


> I know you're just an apprentice, but for conversations's sake, I often find it just as cheap to change the whole fixture.


Because of what you said, I sat down with my boss and we did a quick cost caculation, and the customer saves around $40 a fixture when I retrofit it.

Mind you, costs could be different, and employees for the most part aren't allowed to see "true costs". I think I get billed out at journeyman rates.


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## kaboler (Dec 1, 2010)

Electric_Light said:


> ....I like 5000K lamps for computer task. I find that going back and forth between looking around, looking at screen, paperwork, I find it visually pleasing.


Makes sense to me!!!

On a side note:

I GOT TOTALLY OWNED BY MY SUPPLIER TODAY.

I originally asked for 5000k to match where I'm working, and when I got there, and plugged em in, they were different. So I'm like, "yo supplier, I need 5000k cool white, not 5000k daylight" and he's like "yo noob 5000k is daylight and 4100k is cool white."

Could be 100% right. My project manager didn't throw me a bone, and the journeyman that "helped" me today didn't even know there was more than just "a flourescent tube" hahahaha. 

Damn, flourescents are a mixed lots. Now I have T12s of all shapes and colours, T8s that are different colours, + specialty ones, and hi-lumen ones, and even metric T8s that I have no xp with. At all.

Metric T8s? Someone enlighten me.


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## Electric_Light (Apr 6, 2010)

kaboler said:


> Makes sense to me!!!
> I originally asked for 5000k to match where I'm working, and when I got there, and plugged em in, they were different. So I'm like, "yo supplier, I need 5000k cool white, not 5000k daylight" and he's like "yo noob 5000k is daylight and 4100k is cool white."


I think you guys are both wrong 
They come in 3000, 3500, 4100, 5000 and 6500. 

4100K = almost ALWAYS cool white.
6500K = daylight 
Everything else are called some names you can't decipher like bright white, soft white, kitchen & bath, warm white and what not, so ALWAYS specify as RE80, xx Kelvin. They likely have RE70s too, but those are lower end poor color rendering lamps. 

Ask for General Electric F32T8/SPX50, Sylvania FO32/850, or Philips F32T8/TL850. They're all USA made. 

Accept no substitution. I would steer clear of any other brands as they're usually China made junk. 

Could be 100% right. My project manager didn't throw me a bone, and the journeyman that "helped" me today didn't even know there was more than just "a flourescent tube" hahahaha. 

Damn, flourescents are a mixed lots. Now I have T12s of all shapes and colours, T8s that are different colours, + specialty ones, and hi-lumen ones, and even metric T8s that I have no xp with. At all.



> Metric T8s? Someone enlighten me.


Those are for display cases, signs and appliances that require very specific length. They're not used for general lighting, so ignore 'em. You shouldn't use anything but F32T8, F32T8/U and F54T5/HO for high-bay T5s. Those are the de-facto lamps these days.

The rest aren't produced as many and they cost more, may have to be ordered in and they typically don't last as long. F96T8 was fairly common maybe five years ago, but they're less common now.


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