2 x 2 versus 600 x 600

[Smart $]

So it really is a metric ceiling grid. That's crazy - that the GSA would spec that in the US?

I'm surprised its so close to our standard English (Imperial for Smart$) grid. I guess its probably because they use the same 2' and 4' nominal length lamps in other countries? Or do they use different lamps in other countries?

They use different lamps in other countries. But US manufacturers of metric sized lay ins use US lamp "innards" so we can use standard US lamps.

 

[hmspe]

I think you'll find that metric fixtures use T5 lamps, not T8. T8 is still the standard in my end of the US. A T5 lamp in the "two foot" size is 549mm while a T8 is 590mm.