2 x 2 versus 600 x 600

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charlie b

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An architect is concerned that the 2 foot by 2 foot (603 mm x 603mm) light fixtures that I showed on my plans are not going to fit with the 600 mm x 600 mm ceiling grid that he is showing on his plans. This is a suspended ceiling and the fixtures are recessed troffers. I don't know how these things are actually built, so I don't know if that extra 1.5 mm on each edge is going to be a real problem. Can anyone shed some light (sorry about that) on this issue for me?
 

roger

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An architect is concerned that the 2 foot by 2 foot (603 mm x 603mm) light fixtures that I showed on my plans are not going to fit with the 600 mm x 600 mm ceiling grid that he is showing on his plans. This is a suspended ceiling and the fixtures are recessed troffers. I don't know how these things are actually built, so I don't know if that extra 1.5 mm on each edge is going to be a real problem. Can anyone shed some light (sorry about that) on this issue for me?

Charlie, we bid a Federal Building a few years ago and had to get prices on metric lay-ins, they are definitely different animals and I believe it carried over to the lamps.

BTW, I liked the pun.

Roger
 

steve66

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It shouldn't be a problem. 2x2 recessed lights are made to fit in a 2x2 ceiling grid. The openings in the grid are less than 2'x2' - they are just spaced 2' on center (i.e. 2' from center of tbar to center of tbar).

Edit: I didn't see Rogers post before I posted. I'm assuming Charlie is using an English 2'x2' grid since 600 mm is almost exactly 2'.
 

Fulthrotl

~Autocorrect is My Worst Enema.~
An architect is concerned that the 2 foot by 2 foot (603 mm x 603mm) light fixtures that I showed on my plans are not going to fit with the 600 mm x 600 mm ceiling grid that he is showing on his plans. This is a suspended ceiling and the fixtures are recessed troffers. I don't know how these things are actually built, so I don't know if that extra 1.5 mm on each edge is going to be a real problem. Can anyone shed some light (sorry about that) on this issue for me?

m'kay.... who uses metric ceiling in the US?

1MM=.03945" so you are going to gain an eighth inch or so... if you
put two fixtures end to end, i suspect a problem with fit. putting fixtures
into the correct size grid is sometimes like packing a marshmallow into a
piggy bank.....
 

iwire

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My only experience with the GSA has lead me to believe they are a worthless taxpayer expense. :D

It was like they picked a random unemployable guy, handed him a multi-meter and told him to supervise the electrical installation I was doing for code and specification compliance. I don't know what he was knowledgable in but I know it was not electrical work.
 

GoldDigger

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For anybody interested see page 31 of this document

Roger

Relevant portion, starting on page 30 as I see it,:

When a round metric 600 by 600 or 600 by 1 200 ceiling grid is installed, round metric lay-in type fixture sizes must match.
Many fixture manufacturers currently produce or can produce both modular metric sizes and still utilize currently used standard bulb sizes.
 

Smart $

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I need to clarify that my reference to page 31 was the PDF page, which is page 25 of the actual document.

Roger
Near bottom of document page 30 (pdf page 36) is what GD quoted... and perhaps just as pertinent as it goes on to list known US manufacturers.

PS: I wish document regarding metric sizing would at least get the counterpart name(s) right. English is a dated term that has been replaced by Imperial (aka British Imperial) for about 200 years now. US units of measure can simply be referred to as US customary units.
 
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steve66

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Illinois
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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?
 
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