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2012 IRC: R501.3 I-joist floor protection

Papio Bldg Dept

Papio Bldg Dept

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I am starting to hear about this requirement in the 2012 IRC. Has anyone else heard of this, and can they offer any insight on whether AHJs that have adopted the 2012 are amending or enforcing this section. Thanks in advance.

R501.3 Fire protection of floors.

Floor assemblies, not required elsewhere in this code to be fire-resistance rated, shall be provided with a 1/2-inch (12.7 mm) gypsum wallboard membrane, 5/8-inch (16 mm) wood structural panel membrane, or equivalent on the underside of the floor framing member.

Exceptions:

1. Floor assemblies located directly over a space protected by an automatic sprinkler system in accordance with Section P2904, NFPA13D, or other approved equivalent sprinkler system.

2. Floor assemblies located directly over a crawl space not intended for storage or fuel-fired appliances.

3. Portions of floor assemblies can be unprotected when complying with the following:

3.1. The aggregate area of the unprotected portions shall not exceed 80 square feet per story

3.2. Fire blocking in accordance with Section R302.11.1 shall be installed along the perimeter of the unprotected portion to separate the unprotected portion from the remainder of the floor assembly.

4. Wood floor assemblies using dimension lumber or structural composite lumber equal to or greater than 2-inch by 10-inch (50.8 mm by 254 mm) nominal dimension, or other approved floor assemblies demonstrating equivalent fire performance.
 
fatboy said:
Yes, it is in the 2012 IRC. I plan on adopting the section unamended, and enforce as such.
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Thanks. How is your local building community responding to this section? Does the rational have to do with the quick failure rate of an I-Joist in a fire?
 
Papio Bldg Dept said:
Thanks. How is your local building community responding to this section? Does the rational have to do with the quick failure rate of an I-Joist in a fire?
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That is exactly what we were told.
 
Agree on the rationale, FF's were the proponents.

I have not adopted yet, looking at a 1/1/13 effective date. There will be squawking no doubt, but there are the four exceptions as on option.
 
Thank you all for your input. We will most likely jump from the 2006 to the 2012, but some neighboring jurisdictions have picked up the 2009.
 
Papio Bldg Dept said:
or equivalent on the underside of the floor framing member.
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Is this saying ONLY on each individual joist and not continuously covered from joist to joist to joist? Sounds like some screwy wording?
 
I guess we will have to wait and see if those gyp bd manufacturers start selling 2" strips of gb? I think they were hoping the previous use of the word "assembly" would imply the underlying assumption, and not be taken at their word. Semantics may not be a dying language.
 
Papio Bldg Dept said:
I guess we will have to wait and see if those gyp bd manufacturers start selling 2" strips of gb? I think they were hoping the previous use of the word "assembly" would imply the underlying assumption, and not be taken at their word. Semantics may not be a dying language.
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If they try to start selling two inch strips of me they have to go through the wife first, she has claim to any two inch strip I may have.
 
Darren Emery said:
Why limit this to I-joists? Open web, metal plate trussess can have similiar problems.
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If I had to gues, I would say it probably has more to do with who has the "more better" lobbying groups.
 
Darren Emery said:
Why limit this to I-joists? Open web, metal plate trussess can have similiar problems.
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I don't see the limitation to I-Joist. I see it applies to all floor assemblies except nominal 2x10 demension limber or structural composite. Exception 4
 
The way I read this it would apply to 2x8 sawn lumber. The question is does it apply also to 3x8 sawn lumber? While the width of a 3x is greater than for a 2x the depth is still less than the nominal depth of a 2x10.
 
Massachusetts is moving through the process to adopt an amendment to the 2009 IRC, to require anything besides sawn lumber or solid laminate lumber to be covered.

The amendment was originally proposed by the fire service based on the rapid failure of unprotected engineered floor systems and the requirement in the 2012 IRC. The Massachusetts Federation of Building Officials partnered with the fire officials to limit the requirement to engineer floor system and exempt all sawn lumber. The building community has testified against the amendments based on coast and coordination difficulties.

The Board of Building Regulations and Standards, who promulgate the building code state wide, have stated they are going to pass the 2012 ICC edition of the codes and adopt the 2015 editions of the ICC as the next base code for the state with minimal front end amendments.
 
"The way I read this it would apply to 2x8 sawn lumber. The question is does it apply also to 3x8 sawn lumber? While the width of a 3x is greater than for a 2x the depth is still less than the nominal depth of a 2x10."

Do you really see 2X8 floor joists? I haven't, not over a basement space. Could happen I suppose, but not likely.
 
Papio Bldg Dept said:
I am starting to hear about this requirement in the 2012 IRC. Has anyone else heard of this, and can they offer any insight on whether AHJs that have adopted the 2012 are amending or enforcing this section. Thanks in advance.R501.3 Fire protection of floors.

Floor assemblies, not required elsewhere in this code to be fire-resistance rated, shall be provided with a 1/2-inch (12.7 mm) gypsum wallboard membrane, 5/8-inch (16 mm) wood structural panel membrane, or equivalent on the underside of the floor framing member.

Exceptions:

1. Floor assemblies located directly over a space protected by an automatic sprinkler system in accordance with Section P2904, NFPA13D, or other approved equivalent sprinkler system.

2. Floor assemblies located directly over a crawl space not intended for storage or fuel-fired appliances.

3. Portions of floor assemblies can be unprotected when complying with the following:

3.1. The aggregate area of the unprotected portions shall not exceed 80 square feet per story

3.2. Fire blocking in accordance with Section R302.11.1 shall be installed along the perimeter of the unprotected portion to separate the unprotected portion from the remainder of the floor assembly.

4. Wood floor assemblies using dimension lumber or structural composite lumber equal to or greater than 2-inch by 10-inch (50.8 mm by 254 mm) nominal dimension, or other approved floor assemblies demonstrating equivalent fire performance.
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For those that have adopted the IRC sprinkler requirement the 1st exception is a given; be interested in the rest that have not adopted the sprinkler and if amend changes, but I would not be surprised should they skip the 2012 edition and wait until the 2015 cycle for further study.

Does the 2012 commentary provide any insight to exception 4?

"A: As one of the original proponents of this language, AWC has insight into the intent and discussions leading to development of the wording in this exception. To be considered equivalent to 2x10 sawn lumber or SCL, the framing members should support a load corresponding to 50% of the full bending design of the framing members, while being subjected to an ASTM E 119 time/temperature heating regime. All components utilized in the manufacture of the framing members (fasteners, plates, hardware, etc) should be utilized during testing. The test end criteria should be structural member failure.

AWC believes that the most straightforward and accurate means of determining the required minimum fire resistance time would be to estimate that time using the calculation methodology specified in NDS Chapter 16 for unprotected solid-sawn 2x10 floor joists assuming: a 3-sided exposure, a nominal char rate of 1.5 inches/hr, a bending strength to ASD ratio of 2.85, and supporting a load corresponding to 50% of full bending design."

http://www.awc.org/helpoutreach/faq/FAQfiles/membrane_protection.html

Francis
 
Can you expand on that 2.85 FOS... my understanding was the ASD for wood only has a 2.1 factor of safety?
 
Not sure at this time but I can see us amending it out. Sure dose seem like another interweaving code requirement atempt to "encourage" adoption for RFS?
 
Have you ever seen how lightweight joists react in a fire? The webs go away, and the only thing left is the sub-floor, and a hint of top/bottom cords. Use solid sawn lumber, no problem.
 
fatboy, there is no argument that I-joists fail very fast under fire conditions. Thats well known. It is also well known that truss plate connectors fail fast as well. Why now? I was not at the code hearings but sure wanted to be. Was anybody there to hear the testmony and also enlighten us on exactly who was driving this? Still seems a bit over the top?
 
This provision had been proposed and failed before, waiting for better data and increased awareness to manifest. Have you looked at the test data prepared by UL (posted above)? Have you not at least read about (or talked to your local FD about) the increase in near-misses, injuries, and deaths as use of these materials has become widespread?

You seem to imply that "Sure, everyone knows these things are crap, but why would we want to do anything about that now?"

I don't get it.
 
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