# T-rating of conduit



## SparkyUT78 (May 17, 2011)

I have a few conduit riser racks that go from level 1 to level 4. On each floor these riser are accessible with doors. Instead of being in a shaft they are going through the floor and ceilings of closets. These are large racks of appx 80 1" EMT, also with some 3" & 4" thrown in there. Even though they are not in a wall cavity, are they required to be T-rated. The blockouts are fully grouted back in. These closets will only be accessible to maintenence personell. They do have the fire alarm panels mounted in some of these closets. Does anyone have code references that will state that there is no need for these to be T-rated.

Thank you.


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## Coug Dad (May 18, 2011)

Welcome to the board.  They should not require a T rating.


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## texasbo (May 18, 2011)

Yes, welcome to the board, Sparky.

I'm having a difficult time understanding why this would not be required to be in a rated shaft.


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## jhperez (May 18, 2011)

*2006 IBC*

*707.2* Shaft enclosure required.

3.   A shaft enclosure is not required for penetrations by pipe, tube, conduit, wire, cable and vents protected in accordance with Section 712.4.

*712.4.1.1* Through penetrations.

Through penetrations of fire-resistance-rated horizontal assemblies shall comply with Section 712.4.1.1.1 or 712.4.1.1.2.

Exceptions:

1.   Penetrations by steel, ferrous or copper conduits, pipes, tubes or vents or concrete or masonry items through a single fire-resistance-rated floor assembly where the annular space is protected with materials that prevent the passage of flame and hot gases sufficient to ignite cotton waste when subjected to ASTM E 119 time-temperature fire conditions under a minimum positive pressure differential of 0.01 inch (2.49 Pa) of water at the location of the penetration for the time period *equivalent to the fire-resistance rating of the construction penetrated*. Penetrating items with a maximum 6-inch (152 mm) nominal diameter shall not be limited to the penetration of a single fire-resistance-rated floor assembly, provided the aggregate area of the openings through the assembly does not exceed 144 square inches (92 900 mm2) in any 100 square feet (9.3 m2) of floor area.

2.   Penetrations in a single concrete floor by steel, ferrous or copper conduits, pipes, tubes or vents with a maximum 6-inch (152 mm) nominal diameter, provided the concrete, grout or mortar is installed the full thickness of the floor or the thickness required to maintain the fire-resistance rating. The penetrating items shall not be limited to the penetration of a single concrete floor, provided the area of the opening through each floor does not exceed 144 square inches (92 900 mm2).

3.   Penetrations by listed electrical boxes of any material, provided such boxes have been tested for use in fire-resistance-rated assemblies and installed in accordance with the instructions included in the listing.

*712.4.1.1.2 *Through-penetration firestop system.

Through penetrations shall be protected by an approved through-penetration firestop system installed and tested in accordance with ASTM E 814 or UL 1479, with a minimum positive pressure differential of 0.01 inch of water (2.49 Pa). *The system shall have an F-rating and a T-rating of not less than 1 hour but not less than the required rating of the floor penetrated.*

Exception: Floor penetrations contained and located within the cavity of a wall do not require a T- rating.

What is the fire rating of the floor?  Unless one of the exceptions apply, yes F-ratings and T-ratings are required.


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## texasbo (May 18, 2011)

The racks are penetrating more than one floor, so unless the racks are less than 144 sq. in. in area, the F and T rating requirements are moot; they must be enclosed in a shaft.


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## Examiner (May 18, 2011)

Why would not Section 712.4.2 (2006 IBC) not apply if the horizontal assebmly is not rated?  He does not tell us the occupancy use group and if there are to be rated horizontal assemblies.  I assuming that there are three stories penetrated in a four story building.


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## SparkyUT78 (May 18, 2011)

Thank you

Thanks for all your input on this situation. I was hoping there was some exception out there that I wasn't seeing. These racks do go through multiple floors and definetly is larger than 144 sq in. It will look funny, but I think I'll have a wall built inside the closet so that the penetrations will be in a wall cavity. The space is pretty limited but there should be enough room to build a wall out of 2" studs and 1 layer of 1/2" rock.


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## texasbo (May 18, 2011)

Examiner said:
			
		

> Why would not Section 712.4.2 (2006 IBC) not apply if the horizontal assebmly is not rated?  He does not tell us the occupancy use group and if there are to be rated horizontal assemblies.  I assuming that there are three stories penetrated in a four story building.


Examiner, good point, but note that 712.4.2 says "connecting not more than 3 stories", not "penetrating not more than 3 floors".  OP said it goes from level 1 to 4, so I assumed it was connecting 4 stories and therefore 712.4.2 would not be applicable. Otherwise, if nonrated assemblies, you would be exactly right.


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## Examiner (May 19, 2011)

I just assumed level one is the main ground floor (slab on grade) so level 2 would be the first penetration, level 3 the second and level 4 the third.  Thus not more than 3 stories.  The graphics in the commentary show it that way.  Then the graphics show continuing through the roof.  Four floors but only 3 stories of penetration then through the roof.


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## KZQuixote (May 19, 2011)

SparkyUT78 said:
			
		

> Thanks for all your input on this situation. I was hoping there was some exception out there that I wasn't seeing. These racks do go through multiple floors and definetly is larger than 144 sq in. It will look funny, but I think I'll have a wall built inside the closet so that the penetrations will be in a wall cavity. The space is pretty limited but there should be enough room to build a wall out of 2" studs and 1 layer of 1/2" rock.


I believe the shaft is not required if the building is sprinklered (Sec 708.2 Exception 2). If it's not sprinklered, I doubt your 2" stud with one layer of 1/2" will yield the required 1 hour rating.

Bill


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## Examiner (May 19, 2011)

Tex,

Need help explaining what you said about connection and penetrating.  712 is titled Penetrations, 712.4.2 first complete sentence starts out with Penetrations.  I assume that the penetrating items connect not more than 3 stories.  Just do not understand where you are going with this.


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## texasbo (May 19, 2011)

Examiner said:
			
		

> Tex,Need help explaining what you said about connection and penetrating.  712 is titled Penetrations, 712.4.2 first complete sentence starts out with Penetrations.  I assume that the penetrating items connect not more than 3 stories.  Just do not understand where you are going with this.


My point is that the proposed penetration is not allowed. Per 712.4.1, the maximum area is 144 sq. in. This penetration would exceed that.

Even if the horizontal assemblies are not rated, the penetrations would connect more than three stories (a hole between 1st and 2nd story, a hole between 2nd and 3rd story, and a hole between 3rd and 4th story means all 4 stories are connected by the penetrations), so 712.4.2 would not apply.


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## texasbo (May 19, 2011)

KZQuixote said:
			
		

> I believe the shaft is not required if the building is sprinklered (Sec 708.2 Exception 2). If it's not sprinklered, I doubt your 2" stud with one layer of 1/2" will yield the required 1 hour rating.Bill


Bill, 708.2, exception 2 (2009 IBC) is for escalators. 708.2 Exception 2 in the 2006 IBC is for dwelling unit separation.


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## KZQuixote (May 19, 2011)

texasbo said:
			
		

> Bill, 708.2, exception 2 (2009 IBC) is for escalators. 708.2 Exception 2 in the 2006 IBC is for dwelling unit separation.


Thanks Tex, I see it now.

Bill


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## SparkyUT78 (May 19, 2011)

More info

Here is some more info to help with the discussion.

This is a retail structure that has 4 levels of parking below grade, and 4 levels above grade. These racks start in level P1 (the first level under grade). They come out of the electrical rooms then 90 up to the upper levels. All of the pipes penetrate from P1 to L1. Some shed off on L1 to serve that area, the rest penetrate up to L2. Some shed off on L2 and the rest penetrate up to L3. Again at L3 most shed off and only a few go to L4 which is the mechanical area. Instead of being completly shafted the whole way up, they decided to have the riser going through closets. In the closet they also have the fire alarm panels so they will need access to them.

I was hoping that there would be some exception that since it would only be accessible to maintence personel, and all the walls around were fire rated wall, that it would be considered a shaft. Then there would be no need to do anything extra to T-rate these pipes.

So my solution is to build a wall to enclose the pipes within the closet, thus satifing the exception of coming up in a wall cavity. If I unerstand correctly, the wall cavity does not need to be rated.

Again thanks for all your input. I didn't expect this to be such a good discussion.

My next question is about W-rating, do you guys want to hear it?


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