Fire rated utility Room? Looking for Code Experts

[Angelfire]

Hiya Folks,
I'm getting ready to sheetrock my addition. I have a small enclosed utility room that will house the furnace and water heater. Inside the room is a platform made of OSB that essentially raises the entire floor up about 18". I'd really rather not put sheet rock on the top of this OSB for the furnace and water heater to sit on so was thinking sheet metal. I recall 26 ga carrying a 1 hour fire rating but can't find any confirmation of this. Anyone have a link to where such an assembly I'm talking about shows sheet metal being used on the "floor" to give a fire rating? I suppose if worst comes to worst, I can sheetrock the OSB then place the sheet metal over the rock.
Thanks much.

 

[BWS]

Wonder board,DUROCK comes to mind if we're talkin floors/fireproofing?

 

[Angelfire]

True. Might be a possibility as well. Was leaning towards the sheet metal just for durability sake but could certainly put the cement board under it as well. Thanks!

 

[BWS]

Cement bd is a very cost conscious material....doh.Be it wood stove surrounds,welding cells....and heck,I've used it on homeboy gunsafe liners.

 

[MoonRise]

Call the AHJ and find out what they want/require.

But just putting some thin sheetmetal on top of some OSB is not going to make a 'fire-rated' floor.

FYI, a 1-hour fire-rated structure is something like double 5/8 Type X drywall on both sides with studs (2x4 or 2x6 wood, or steel studs) with or without insulation.

Durock (1/2") on top of (nominal) 1/2" plywood (15/32 actual) on top with 2x4 framing and 5/8 Type X drywall on the 'other' side gets a 1 hr fire rating.

Call and find out what is wanted/required.

Found a reference to a fire-rated sheetmetal wall panel. 4" thick, 26 gauge G90 galvanized steel facings, and stuffed with mineral wool insulation. But I think the 4" thick rockwool isthe key there.

http://www.kingspanpanels.us/media/60580/MF Technical Data.pdf

 

[Falcon67]

Cement bd is a very cost conscious material....doh.Be it wood stove surrounds,welding cells....and heck,I've used it on homeboy gunsafe liners.

Duh-Oh! I just bought a roll of flashing to use for use over the OSB backing my welding table and I here I have a sheet of HardiPanel laying behind the building! ID-10-T error.

 

[woodrail]

Why are you fire-rating the floor? Do you have a basement? If this is just a platform over a slab, iwould tend to just rate the walls and ceiling from the slab to struccture above.

Could you provide a couple of pic's?

 

[Angelfire]

Why are you fire-rating the floor? Do you have a basement? If this is just a platform over a slab, iwould tend to just rate the walls and ceiling from the slab to struccture above.

Could you provide a couple of pic's?

The floor is concrete and the platform is about 18" off the concrete. The platform is walled in to create the plenum for the furnace. So I'm not fire rating the floor but the top of the platform which serves as the top of the plenum below. According to my HVAC guy, the top of the OSB needs to be covered in 5/8" type X to provide protection to the plenum (and hence spreading to other rooms I guess). In any case, I don't want to have equipment sitting on top of the rock so was looking to just use sheetmetal if possible but to cover me ****, I may just put sheetmetal over the rock or durock as suggested above. My inspector indicated the room had to be completely rocked with type X which I took to mean the OSB under the furnace/water heater as well.

 

[yzair]

5/8 type x rock is code in California for 1 hr. rating. If the equipment isn't installed yet put greenboard on the inside of plenum and fire tape joints.

 

[woodrail]

...and it's a mute point anyway unless you have fire dampers on the supply and return ductwork.

This is single family residential construction?

 

[ddawg16]

5/8 type x rock is code in California for 1 hr. rating. If the equipment isn't installed yet put greenboard on the inside of plenum and fire tape joints.

^^that....

I'm building a new enclosure for my water heater....5/8" Type X drywall.

Funny thing...they are not worried about the base....1/2" plywood is ok. I'm assuming that because the flame and heat go up...it will propagate away from the base.

 

[Angelfire]

...and it's a mute point anyway unless you have fire dampers on the supply and return ductwork.

This is single family residential construction?

Agreed but it's not a moot point if that's what the inspector requires. It's amazing actually to see how they all seem to interpret the codes differently