I noticed that all of the F15T8's are claimed to have 7500 hours life at 6 (SIX!!) hours per start, and the F15T12's are 9000 hours at 6 hours per start.

I can tell you I have never had a GE made in Indonesia make 7500 hours. A friend of mine is sorta kind a getting close to 7300 hours at 8 to 12 hours per start.

Powell

I noticed that all of the F15T8's are claimed to have 7500 hours life at 6 (SIX!!) hours per start, and the F15T12's are 9000 hours at 6 hours per start.

I can tell you I have never had a GE made in Indonesia make 7500 hours. A friend of mine is sorta kind a getting close to 7300 hours at 8 to 12 hours per start.

Powell

It's a median life based on a fairly large sample size using ANSI testing conditions using ANSI reference ballast and 3hrs/cycle. I believe the off time between each cycle is five or 15 minutes, but I don't remember for sure.

We have "life expectancy" for people too, but as we all know, people don't die at that age exactly. If you set up 100 of them and run them under ANSI testing conditions, then you can expect ~50 to fail after rated hours.  All fluorescent lamps have an inverted S shaped mortality curve.  

Even outside of ANSI reference conditions(as long as it does not exceed limits, like LCCF), if the hours per cycle is similar, it should be fairly close.  What was the sample size of your friend's lamps?

My friend has been using the GE Indonesian made F15 T8 CW lamps for years. That is all he can get in his small town.
VERY little variance in life.


Powell

My friend has been using the GE Indonesian made F15 T8 CW lamps for years. That is all he can get in his small town.
VERY little variance in life.


Powell

I ask again. What is the sample size. (how many lamps total?)

Since the fixtures are a 2 lamp Art Craft and the lamp over the washing machine, I think a bit over a dozen maybe more. But not ANY have done more. A FEIT bulb that looks like it was made in the same factory did a few thousand hours before going FFFFFFFFEEEET!


Powell

I have all 5 lamps from my friend AND 2 F20 T12 lamps. I have EOLed 3 and 2 more to go. The F20 lamps won't quit. All of them did like my EOL pictures in my gallery.