# Fire/Rad dampers in 1/2 hr rated floor over crawl space?



## bmcdaniel (Sep 1, 2015)

So we're renovating an old house, and based on the use it requires the floor over the crawl space to be 1/2hr rated per the architect. The building is sprinkled. I've read over the IBC several times, and I found where if the rating is 1hr or less in a sprinkled building, fire dampers are not needed in a "wall". It doesn't say floor or fire barrier or rated assembly or any of that. It specifically says "wall", which frankly doesn't make much sense to me. I don't have the commentary available to check the interpretation so I'm kinda stuck. Do I really need radiation dampers or fire dampers at my residential style floor registers? I can't for the life of me find a manufacturer that make residential style floor registers with rad dampers either.

Thanks in advance!


----------



## cda (Sep 1, 2015)

Welcome welcome and


----------



## cda (Sep 1, 2015)

Is the building going to be used for residential or commercial??

As in should you be looking at IRC or IBC?


----------



## bmcdaniel (Sep 2, 2015)

It's classified as commercial, so it falls under the IBC.


----------



## mtlogcabin (Sep 2, 2015)

717.6 Horizontal assemblies.

Penetrations by ducts and air transfer openings of a floor, floor/ceiling assembly or the ceiling membrane of a roof/ceiling assembly shall be protected by a shaft enclosure that complies with Section 713 or shall comply with Sections 717.6.1 through 717.6.3.

717.6.1 Through penetrations.

In occupancies other than Groups I-2 and I-3, a duct constructed of approved materials in accordance with the International Mechanical Code that penetrates a fire-resistance-rated floor/ceiling assembly that connects not more than two stories is permitted without shaft enclosure protection, provided a listed fire damper is installed at the floor line or the duct is protected in accordance with Section 714.4. For air transfer openings, see Section 712.1.8.

Exception: A duct is permitted to penetrate three floors or less without a fire damper at each floor, provided such duct meets all of the following requirements:

1.	The duct shall be contained and located within the cavity of a wall and shall be constructed of steel having a minimum wall thickness of 0.0187 inches (0.4712 mm) (No. 26 gage).

2.	The duct shall open into only one dwelling or sleeping unit and the duct system shall be continuous from the unit to the exterior of the building.

3.	The duct shall not exceed 4-inch (102 mm) nominal diameter and the total area of such ducts shall not exceed 100 square inches (0.065 m2) in any 100 square feet (9.3 m2) of floor area.

4.	The annular space around the duct is protected with materials that prevent the passage of flame and hot gases sufficient to ignite cotton waste where subjected to ASTM E 119 or UL 263 time-temperature 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.


----------



## bmcdaniel (Sep 2, 2015)

The exception states that the duct has to meet all of the requirements to take the exception. My situation is more in line with 717.6.2, Membrane penetrations, yet that only covers floor/ceiling and roof/ceiling assemblies, and not floor/crawl space assemblies which is what I have here.


----------



## cda (Sep 2, 2015)

can you site the section that requires the floor to be rated???

Just wonder why a ground floor, floor hs to be rated, unless you have basement below it.


----------



## mtlogcabin (Sep 2, 2015)

bmcdaniel said:
			
		

> The exception states that the duct has to meet all of the requirements to take the exception. My situation is more in line with 717.6.2, Membrane penetrations, yet that only covers floor/ceiling and roof/ceiling assemblies, and not floor/crawl space assemblies which is what I have here.


711.3.3 Unusable space.

In 1-hour fire-resistance-rated floor assemblies, the ceiling membrane is not required to be installed over unusable crawl spaces. In 1-hour fire-resistance-rated roof assemblies, the floor membrane is not required to be installed where unusable attic space occurs above.

In a floor ceiling assembly the fire side is the ceiling side and if it is not required then a damper is not needed


----------



## bmcdaniel (Sep 2, 2015)

That's fantastic, thought where does it state that the ceiling is the fire side and if it's not required, no damper is needed? We typically do health care and schools and such, so haven't had the need to delve into this area at all until now.

I appreciate your help with this!


----------



## cda (Sep 2, 2015)

bmcdaniel said:
			
		

> That's fantastic, thought where does it state that the ceiling is the fire side and if it's not required, no damper is needed? We typically do health care and schools and such, so haven't had the need to delve into this area at all until now. I appreciate your help with this!


OK where did a ceiling come into play?

What code section requires this  """"it requires the floor over the crawl space to be 1/2hr rated per the architect""""  ???

And once again is this over a basement? of ground level crawl space???


----------



## bmcdaniel (Sep 2, 2015)

It's an old house on a crawl space that's been converted into a shelter. The architect did the research to determine the ratings, so I'm not sure where in the code that is. We are using floor registers on the ground floor, with the ductwork in the crawl space fed from a gas pack on grade. Since the floor over the crawl space needs a 1/2 hr fire rating (not more because the house is sprinkled), I needed to determine whether or not fire protection was needed at the floor since this is a membrane penetration. This is a horizontal assembly, and as mtlogcabin pointed out, it's over an unusable space, thus the "ceiling" side of the horizontal assembly (the underside of the floor joists) need not be rated. I am inclined to believe mtlogcabins statement after that, but I want to make sure we have a solid case if the code officials question not having dampers.


----------



## cda (Sep 2, 2015)

"""crawl space that's been converted into a shelter."""

so the shelter will not be used?

There is no access to the shelter"

How tall, and length/width is the shelter?

I am thinking no rating is required?


----------



## bmcdaniel (Sep 2, 2015)

"""It's an old house on a crawl space""" Don't forget the first part of that sentence.    Sorry if I'm not being more clear, I thought I was. It's a residential house that has been repurposed for commercial use.

 i.e. A shelter to house people who need housing. It's run by DHEC. Commercial codes, not residential apply.


----------



## cda (Sep 2, 2015)

Ohhhhh

still do not think the floor needs to be rated, but anyway, that is not your problem

Your problem is going through the floor


----------



## mtlogcabin (Sep 2, 2015)

bmcdaniel said:
			
		

> That's fantastic, thought where does it state that the ceiling is the fire side and if it's not required, no damper is needed? We typically do health care and schools and such, so haven't had the need to delve into this area at all until now. I appreciate your help with this!


722.6.2.4 Floors and roofs.

In the case of a floor or roof, the standard test provides only for testing for fire exposure from below.


----------



## mtlogcabin (Sep 2, 2015)

Unless you have combustible storage in the crawlspace I do not recall a requirement to rate the floor

What is the occupancy classification?

Is the crawl space sprinkled?


----------



## Builder Bob (Sep 3, 2015)

IBC

SECTION 413 COMBUSTIBLE STORAGE

413.1 General.

High-piled stock or rack storage in any occupancy group shall comply with the International Fire Code.

413.2 Attic, under-floor and concealed spaces.

Attic, under-floor and concealed spaces used for storage of combustible materials shall be protected on the storage side as required for 1-hour fire-resistance-rated construction. Openings shall be protected by assemblies that are self-closing and are of noncombustible construction or solid wood core not less than 13/4 inch (45 mm) in thickness.

Exception: Neither fire resistant construction nor open protectives are required in any of the following locations:

1. Areas protected by approved automatic sprinkler systems.

2. Group R-3 and U occupancies.

Install fire sprinklers in the crawl space and do away with the rating and opening protective.......


----------



## cda (Sep 3, 2015)

Builder Bob said:
			
		

> IBC SECTION 413 COMBUSTIBLE STORAGE
> 
> 413.1 General.
> 
> ...


413 ibc does not apply to a house

Unless it is very big and storing a lot of stuff high

Also,,,, the op is hvac, so he is not installing the Sheetrock

Just cutting big hole in it


----------

