# Insulated Fire Rated Assemblies



## Mech (Jun 11, 2012)

2009 IBC

This may sound like a dumb question, but does the code specifically say that fiberglass insulation can be used in fire rated assemblies?

Thanks


----------



## RLGA (Jun 11, 2012)

No, only if the tested assemblies indicate whether insulation is acceptable or not.  Table 720.1(2) does not mention the allowance of insulation in a fire-resistance walls, either.

With that said, Section 721.6 for calculated fire resistance in wood assemblies does allow fiberglass, rock wool, or slag wool batts in wood frame wall assemblies.


----------



## mtlogcabin (Jun 11, 2012)

No it does not and it can hinder the rating of some floor ceiling assemblies See GA FC5110 & GA FC5106

Some listed assemblies allow it for sound without affecting the rating

but the code only mentions mineralwool, rock wool or slag wool

TABLE 721.6.2(5)

TIME ASSIGNED FOR ADDITIONAL PROTECTION

Add to the fire-resistance rating of wood stud walls if the spaces between the studs are completely filled with glass fiber mineral wool batts weighing not less than 2 pounds per cubic foot (0.6 pound per square foot of wall surface) or rockwool or slag material wool batts weighing not less than 3.3 pounds per cubic foot (1 pound per square foot of wall surface), or cellulose insulation having a nominal density not less than 2.6 pounds per cubic foot.


----------



## mark handler (Jun 11, 2012)

What is the purpose of the insulation?

 fireblocking?



> 717.2.1.2 Unfacedl fiberglass. Unfaced fiberglass batt insulation used as fireblocking shall fill the entire cross section of the wall cavity to a minimum height of ·16 inches (406 mm) measured vertically. When piping, conduit or similar obstructions are encountered, the insulation shall be packed tightly around the obstruction.


Almost every assrnbly in the GA 600 has an insulation option



> Table 720.1 footnotes Generic fire-resistance ratings (those not designated as PROPRIETARY* in the listing) in the GA 600 shall be accepted as if herein listed.


----------



## TheCommish (Jun 11, 2012)

Fire rated assembly need to be assembly with the components and as specified in the UL or equal listing.  If the test assembly has fiberglass by corning then the real life has to have corning insulation in it.

If the  assembly does not have insulation in its listing then leave the insulation out or have the RDP specify another assembly with insulation in if they need it for  energy reason.


----------



## Mech (Jun 12, 2012)

Insulation is for energy reasons.  I have some exterior wood stud walls needing a 1 hr rating and I also have a wooden I-joist floor assembly, over an unheated basement, needing a 1 hr rating.


----------



## AegisFPE (Jun 12, 2012)

From Gypsum Association GA-600 _Fire Resistance Design Manual_, referenced in IBC Table 720.1(#) footnotes:



> Note 10. When not specified as a component of a fire tested wall or partition system, mineral fiber, glass fiber, or cellulose fiber insulation of a thickness not exceeding that of the stud depth shall be permitted to be added within the stud cavity.Note 11. In floor-ceiling or roof-ceiling systems, the addition or deletion of mineral or glass fiber insulation in ceiling joist spaces could possibly reduce the fire resistance rating...


----------



## cda (Jun 12, 2012)

Mech said:
			
		

> Insulation is for energy reasons.  I have some exterior wood stud walls needing a 1 hr rating and I also have a wooden I-joist floor assembly, over an unheated basement, needing a 1 hr rating.


as stated before possibly a horizontal assembly cannot have insulation, unless tested with it!!!!!!!!

it throws the fire off for some reason, for got why


----------



## brudgers (Jun 13, 2012)

cda said:
			
		

> as stated before possibly a horizontal assembly cannot have insulation, unless tested with it!!!!!!!!  it throws the fire off for some reason, for got why


  It prevents heat from transferring through the assembly creating a higher temperature on the fire side.


----------



## cda (Jun 13, 2012)

brudgers said:
			
		

> It prevents heat from transferring through the assembly creating a higher temperature on the fire side.


Yea that is it had slow brain day


----------



## Examiner (Jun 13, 2012)

Fire is hotter in the horizontal position and that is why you cannot take a vertical 1-hour steel stud wall system and use it for a rated corridor cap.  How many times have I seen Architects do that!


----------



## Big Mac (Jun 13, 2012)

As mentioned before, fire-rated assemblies must be installed exactly as the assembly tested to be acceptable.  That being said, it isn't all that difficult to find a one-hour tested assembly with fiberglass insulation in either the Gypsum Manual or the UL Manual.  I would accept a fire-rated tested assembly from either manual as adequate.


----------



## AegisFPE (Jun 13, 2012)

Examiner said:
			
		

> take a vertical 1-hour steel stud wall system and use it for a rated corridor cap.


This is permitted by Exception 3 of IBC Section 709.4; from the Commentary:



> This is a unique provision in the code and the fact that it permits a wall assembly to be turned into a horizontal position should not be applied to other sections of the code or other rated assemblies. In this one situation, the code will permit an assembly that has been tested as a wall to be turned and used horizontally.


----------



## Examiner (Jun 13, 2012)

Thanks AegisFPE.  Must have overlooked it or just forgot it was there.  I am still leaning something every day.  In the 2006 IBC it is in Section 708.4 Exception 3.


----------

