• Welcome to The Building Code Forum

    Your premier resource for building code knowledge.

    This forum remains free to the public thanks to the generous support of our Sawhorse Members and Corporate Sponsors. Their contributions help keep this community thriving and accessible.

    Want enhanced access to expert discussions and exclusive features? Learn more about the benefits here.

    Ready to upgrade? Log in and upgrade now.

UL penetration firestop system question

Sifu

Sifu

SAWHORSE
Joined
Sep 3, 2011
Messages
3,318
I have not been able to find a specific system for a through penetration of U341, a double tenant separation wall in an R2 (see below). All of the systems I find state the following:

1. Wall Assembly — The 1 or 2 hr fire-rated gypsum board/stud wall assembly shall be constructed of the materials and in the manner described in the individual U300, U400 or V400 Series Wall or Partition Design in the UL Fire Resistance Directory and shall include the following construction features:

  1. A. Studs — Wall framing may consist of either wood studs or steel channel studs. Wood studs to consist of nom 2 by 4 in. (51 by 102 mm) lumber spaced 16 in.
My question is that the above statements seem to contradict each other. It appears at first to say that any U300 series construction assembly can be penetrated by this system, then it has specific criteria that the construction assembly "shall include".

The U341 construction assembly allows wood stud spacing up to 24", but the specific for the studs shown above limits the wood stud spacing to 16". So I am confused by the fact that there seems to be a contradiction in the firestop system instructions.


U341
ul6210.jpg
 
The through-penetration system was probably tested in a wall assembly with only studs at 16 inches on center, thus the limitation. The wall assembly states "spaced 24 in. OC max.," which means the studs can be spaced closer together. If a U341 assembly has that through-penetration, then the penetration requirements are more specific, thus, superseding the wall assembly requirements.
 
I think I agree......a penetration firestop system that specifies 16" stud spacing can't be used in a wall assembly with stud spacing greater than that? So my U341 has 24" spacing, I need an assembly that allows that spacing. (Even though item #1 says any U300 series, since item A specifies 16" it couldn't be used for the 24" spacing.)
 
You must log in or register to reply here.
Back
Top