Fire Rated Assemblies

[nickedemus]

I have an exterior 2x6 wall under an exterior that needs to have 1-hour construction. I'm familiar with the USG site and have looked through it, however all of the exterior walls shown with 2x6s are for 2 hour construction. I'd prefer not to over-design. Is there a section of the code that I can reference, which states that 5/8" type x gyp board has a 1 hour rating?

 

[RLGA]

I am assuming stud spacing is 16 inches o.c.

There are plenty. See UL Design No. U305 for one such example (https://iq.ulprospector.com/en/profile?e=14888).

If you have a copy of GA-600, look at GA File No. WP 3605.

 

[cda]

You do not say which edition of IBC

You can also look at 721/ 722



TABLE 722.6.2(1)

 

[Paul Sweet]

I know that using a deeper or heavier gauge steel stud will not reduce the fire rating of a rated assembly. I don't see how using 2x6 studs would reduce the fire rating of assemblies tested with 2x4 studs.

 

[RLGA]

I know that using a deeper or heavier gauge steel stud will not reduce the fire rating of a rated assembly. I don't see how using 2x6 studs would reduce the fire rating of assemblies tested with 2x4 studs.

You're right, it doesn't. Both GA-600 and UL state in their respective guidelines that the stud sizes indicated are minimums. Stud spacing, per the guidelines, is the maximum; thus, a system with studs at 24" o.c. could be constructed with studs at 16" o.c., but a system with studs at 16" o.c. could not be constructed with studs at 24" o.c.

 

[nickedemus]

There are plenty. See UL Design No. U305 for one such example

Thanks, but I've seen this one. It is an interior partition utilizing 2x4s. I'm looking for an exterior partition that utilizes 2x6s that is specifically 1 hour.

 

[nickedemus]

You do not say which edition of IBC

You can also look at 721/ 722

This is what I'm looking for. Thanks!

 

[RLGA]

Thanks, but I've seen this one. It is an interior partition utilizing 2x4s. I'm looking for an exterior partition that utilizes 2x6s that is specifically 1 hour.

These can be used for either interior or exterior. If you look at the details of the assembly (the products specifically), many of the gypsum board products are for exterior heating. You can add an exterior wall covering to the base wall system, just like you can add finishes to an interior fire-rated wall, except that the exterior wall cladding will need to comply with Chapter 14.