Troffers in one hour grid

[ryan_618]

I did an inspection yesterday for a school. The building is not fire sprinklered and therefore the corridors are required to be fire rated. The way the contractor decided to create this rated corridor is by building 1 hour walls to make up the walls of the corridor, but instead of using ceiling joists with 5/8X gypsum board on each side for the ceiling, he decided to use a hour grid ceiling.

The problem is the penetrations. Not only does the grid T-bar itself have to be rated (listed) one hour, but so do the ceiling tiles. Everything is fine, except for the lights.

Question: Have you ever had to come up with a listed one hour protection method for 2X4 lay-in fixtures in a one hour ceiling grid assembly?

I have had people install can lights in one hour sheetrock ceilings that box around the cans with sheetrock and eliminate a membrane penetration, but these lights are a through penetration, and therefore simply wrapping them in 5/8" gyp board isn't going to do it.

Anyone dealt with this???

 

[sandsnow]

Re: Troffers in one hour grid

Ryan
We have entire buildings that had one hour ceiling grid.
One important point is that tbar alone does not make a one hour assembly. Tbar is only one of two membranes that make up a one hour floor ceiling OR roof ceiling assembly. The contractor needs to show you the UL assembly. The UL assembly diagrams will show the protection to be used with the fixtures. The ceiling system manufacturer should be able to provide the system numbers that his product is covered under. if there is a Tbar system that is one hour by itself, it is fairly new or I'm a lot more behind than I thought
Is he making a tunnel corridor? If so the exception in the UBC only allows for tunnel "top" to be made out of sheet rock. Don't know which bldg code you are on.

 

[curt swartz]

Re: Troffers in one hour grid

I know the fixture manufactures can supply troffers labeled for use in a listed fire rated ceiling assemblies. I don?t have much experience with this so don?t know what else is required. I will look to see if I can find any other information but probably will not be able to do any research this until the weekend. I will post anything I find.

 

[gene]

Re: Troffers in one hour grid

Columbia lighting offers troffer fixtures with a fire rated label as an option. I would assume that if so labeled it must be fire rated. The label option is FRL.

 

[ryan_618]

Re: Troffers in one hour grid

The problem is that the grid itself is a full one hour. Any penetrations of it are therefore a penetration through the entire assembly, not just half of it. I actually talked with the electricians a few minutes ago and they are going to rip out the lights and install wall sconces I have asked for listing on everything, tile, grid, fire and smoke dampers, the whole ball of wax. The electrician (wisely) decided to just get out of the ceiling.

 

[roger]

Re: Troffers in one hour grid

Ryan, go Fire Resistive Design and punch in d205, d209, and d215, for a few assemblies.

Roger

[ August 27, 2004, 09:25 AM: Message edited by: roger ]

 

[sandsnow]

Re: Troffers in one hour grid

Roger
The assemblies you said to search for are exactly what I was talking about. You have to have the upper assembly(the deck) to get an hourly rating. They also show how to protect the fixtures

 

[gene]

Re: Troffers in one hour grid

Check this web page for fire rated ceilings and troffers http://www.columbia-ltg.com/techdata/fr-info.html

 

[ryan_618]

Re: Troffers in one hour grid

Thanks for all the input guys. As it turns out, they could not find a listing for a grid ceiling that, in and of itself, creates a one hour asembly. All of the listings require some sort of a second membrane above the ceiling grid, which they do not have. Now they decided to rip out the grid (for the second time) and install a hard lid.