When do recessed lights need to be firebox?

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Waterboy

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My understanding has been that they need to be boxed to match the fire rating of the ceiling assembly rating. The other day, on a two-story single-family home with zero lot line the contractor was fire boxing the recessed lighting with 5/8" drywall within 5 feet of the property line is this necessary or would 1/2" drywall been ok seeing that the ceiling is only half inch?

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Waterboy said:
My understanding has been that they need to be boxed to match the fire rating of the ceiling assembly rating. The other day, on a two-story single-family home with zero lot line the contractor was fire boxing the recessed lighting with 5/8" drywall within 5 feet of the property line is this necessary or would 1/2" drywall been ok seeing that the ceiling is only half inch?

Thanks
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Recessed lighting-property line? You've got me confused!:huh:
 
Waterboy said:
My understanding has been that they need to be boxed to match the fire rating of the ceiling assembly rating. The other day, on a two-story single-family home with zero lot line the contractor was fire boxing the recessed lighting with 5/8" drywall within 5 feet of the property line is this necessary or would 1/2" drywall been ok seeing that the ceiling is only half inch?

Thanks
Click to expand...

Recessed luminaires not rated for direct contact with thermal insulation are required to keep thermal insulation at least 3 inches away from the luminaire. I have seen people box these in in the past thinking that makes them suitable for the application. My opinion has always been that you are still entrapping heat around the luminaire which was the point of keeping insulation away in the first place.

I could see building inspectors requiring boxing them in with 5/8 drywall if ceiling finish rating required 5/8 drywall (notice you said it was 1/2") and the luminaire is not an airtight style - but then you may end up with performance issues - open style usually need air to flow through them to keep them cooled. Seen this first hand when a fire marshal decided to disapprove an open style luminaire well after the original install. He decided that it would be acceptable to put a lens in the trims to reduce possible smoke and air leaks through the luminaire, they almost immediately started having lamp and ballast failures because there was restricted air flow for cooling these items.
 
Well I see your in San Fransisco, that may have a lot more to do with it then anything eles. That being said, since it is a zero clearance lot line (one house's wall is touching, or within inches of the neigbors wall) you need a fire rating in that wall and a parapit wall on the roof to maintain the common fire wall. If there is no parapit wall on the roof, you need a "Horizontal fire separation" this would be the roof or ceiling. That is why five feet. It is in the building code not the NEC and has nothing to do with the IC or Air tight rating of the light.
 
I just roughed a resturaunt where it was a drywalled 2 hour fire rated ceiling. Twenty-five cans went in the ceiling and we needed to install those Tenmat domes. At $60 a dome, our cost, that was an expensive extra. (The print we did our quote off of speced a suspended 2x4 tile ceiling.)
 
K_Buz said:
I just roughed a resturaunt where it was a drywalled 2 hour fire rated ceiling. Twenty-five cans went in the ceiling and we needed to install those Tenmat domes. At $60 a dome, our cost, that was an expensive extra. (The print we did our quote off of speced a suspended 2x4 tile ceiling.)
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Sounds like a good reason to me to adjust the contract, you were not installing to the specifications that were given to you when you gave them a cost.
 
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