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Wood Floor Floor Fire Rating

D

Dominic

SAWHORSE
Joined
Jun 20, 2017
Messages
49
Location
Albany
I am designing a 2 story double loaded 12-plex apartment building (6 down and 6 up). The building is wood framed with open web floor trusses. I want to run the duct in the open web in the first floor with diffusers with fire dampers penetrating ceiling membrane for the first floor and diffusers with fire dampers penetrating the floor membrane for the second floor. The floor assembly is UL L521.

The mechanical engineer said he cannot find dampers that are approved to penetrate the floor so we need to design fire rated shafts to service the seond floor. Not sure I agree.

What are thoughts out there?
 
Not into dampers

Maybe the reason for no floor dampers,,,,

No way to gather heat, for the link to fuse???
 
Only ceiling penetrations are required to have dampers per Section 717.6.2 (2018 IBC).

Horizontal assemblies are only tested for fire resistance from below, so the exposure of opening on the topside will not be detrimental to the assembly.

However, if the duct turns up and down at the same location, then it would likely be considered a through penetration and would need to comply with Section 717.6.1 (2018 IBC).
 
I responded to the incorrect person.

It would be 2 different furnaces. One furnace servicnig the first floor with a ducted system and another furnace furnace servicing the second floor with its own duct. Two different duct systems.

Is there any documents regarding the first statement on floor penetrations?
 
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RLGA said:
Only ceiling penetrations are required to have dampers per Section 717.6.2 (2018 IBC).

Horizontal assemblies are only tested for fire resistance from below, so the exposure of opening on the topside will not be detrimental to the assembly.

However, if the duct turns up and down at the same location, then it would likely be considered a through penetration and would need to comply with Section 717.6.1 (2018 IBC).
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RLGA see comment below.
 
cda said:
What he said.

Normally fire burns up. Keep forgetting those things
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Agreed. Some times trying to explain the laws of physics to a Building Inspector is tough. I was hoping to have documentation or code interpertation.

Anything?
 
Dominic said:
Agreed. Some times trying to explain the laws of physics to a Building Inspector is tough. I was hoping to have documentation or code interpertation.

Anything?
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As some code wizards say,,,, If it ain’t in the code,,,, it ain’t required.
 
Dominic said:
Agreed. Some times trying to explain the laws of physics to a Building Inspector is tough. I was hoping to have documentation or code interpertation.

Anything?
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The code citation I gave specifically says "Ducts and air transfer openings constructed of approved materials in accordance with the International Mechanical Code that penetrates the ceiling membrane of a fire-resistance-rated floor/ceiling or roof/ceiling assembly shall be protected with one of the following:" There is no mention of a duct or air transfer opening that penetrates the floor membrane; thus, no requirement to protect openings through the floor surface.
 
RLGA said:
The code citation I gave specifically says "Ducts and air transfer openings constructed of approved materials in accordance with the International Mechanical Code that penetrates the ceiling membrane of a fire-resistance-rated floor/ceiling or roof/ceiling assembly shall be protected with one of the following:" There is no mention of a duct or air transfer opening that penetrates the floor membrane; thus, no requirement to protect openings through the floor surface.
Click to expand...
Thank you!
 
Dominic, back to your original post. Your mechanical engineer is correct, a fire damper is not tested and listed for installation in a combustible floor, or if one has recently been tested for such use, I am not aware. 2015 IMC Section 607.6.3, number 3 added language to address this in nonfire-resistance-rated floor assemblies but apparently overlooked this in 607.6.1, or thought that fire-resistance-rated floor/ceiling assemblies couldn't be constructed of combustible materials. Its the listing that is being violated here, regardless of the floor rating (see IMC 304.2, Conflicts). IBC references are 717.6.3 and 717.6.1
 
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