I need to design a partition wall in an existing type 1a building with a fire rated roof. The partitions need to be braced to the underside of the metal decking of the ceiling/roof assembly. Is it ok to penetrate the existing assembly with screws?
What about bracing to a fireproofed beam?
Thank you
Chad Miller
Dec 21, 23 10:19 am
What dose the UL listing for the existing assembly say is allowed?
I'd probably ask your AHJ what they think will be allowed. You'll need that in writing when your special inspection is done.
Hiker26
Dec 21, 23 10:31 am
Well it’s existing. I suppose I should find a similar ul. I can’t really tell what the assembly is besides being able to see the underside of deck
Chad Miller
Dec 21, 23 10:44 am
Find an assembly you think is similar to the existing floor.
Meet with the AHJ.
Explain your reasoning for why you can attach screws to the existing assembly.
See if they agree
Hiker26
Dec 21, 23 10:48 am
Thank you
Chad Miller
Dec 21, 23 11:23 am
You bet! Good luck with this. I know it's a pain to deal with.
Bench
Dec 21, 23 1:07 pm
These are the reasons why i still like going to archinect. Genuinely interesting but very non-sexy question. Thx! (Also more of this type of stuff)
JLC-1
Dec 21, 23 1:43 pm
Page 64 shows screw size and spacing for the rated assemblies, but it's for the face screws; I don't think there's a rule when you are attaching a partition if said partition will also be rated.
agreed...the tested assembly involves the required fastening. So, unless you're violating the assembly by removing required fasteners (or other materials), you should be good adding fasteners to that structure
proto
Dec 21, 23 2:36 pm
I don't think additional fasteners violate the fire rating of the existing protected roof, unless they are wood pegs (or other weird thing) or somehow create voids/interruptions in the rated roof assembly
Chad Miller
Dec 21, 23 3:05 pm
Typically that is correct. It all depends on the rated assembly and the number / size of the fasteners though. I know of several 2 hour assemblies that have requirements for penetrations of any type (including fasteners) that need to be sealed with fire caulk.
Hiker26
Dec 21, 23 2:37 pm
This wouldn’t be a rated partition..
Non Sequitur
Dec 21, 23 2:48 pm
We always include typical details for these situations. Usually for a non-rated assembly head detail at a rated assembly, we specify a slotted top track without issue about fastener spacing. It's not like it's adding new loads from underneath that could reduce the performance of the steel deck. Head details at rated gypsum membrane ceilings are another thing and far more complicated.
Hiker26
Dec 21, 23 3:05 pm
It’s not that it’s adding a load from beneath, just the fact that you are penetrating the membrane of the assembly…
Non Sequitur
Dec 21, 23 3:16 pm
are there other devices screwed to u/s of existing deck such as lights and carrying channels? How are those fasteners treated?
JLC-1
Dec 21, 23 4:27 pm
what membrane?
Almosthip
Dec 21, 23 4:32 pm
The fire protection membrane
Non Sequitur
Dec 22, 23 7:54 am
JLC, not sure how it’s down south, but membrane is what we refer to when detailing fire separations made of gypsum sheets. At least that’s how my code calls them.
and this is how the 2021 IFC confuse the terms and doesn't really define what a membrane is
Hiker26
Dec 21, 23 3:19 pm
It’s not that it’s adding a load from beneath, just the fact that you are penetrating the membrane of the assembly…
Hiker26
Dec 21, 23 3:20 pm
Yes there are other things screwed in, I didn’t notice any fire caulk
Non Sequitur
Dec 21, 23 3:30 pm
"fire caulk" is primarily for smoke sealing. Side note, seach the forum for the classic "show me your caulk" discussion.
Chad Miller
Dec 21, 23 4:09 pm
Fire caulking is only required on rare occurrences for certain types of assemblies. Hence why you need to find an assembly similar to the existing ceiling. Realistically you won't need to worry about the fasteners penetrating the membrane of the rated assembly.
Hiker26
Dec 21, 23 3:21 pm
It’s a typical steal frame metal deck system. I’m thinking ul902
proto
Dec 21, 23 5:52 pm
my guess is the steel deck itself is not adding much value to the fireproofiness of your existing condition, whether what's above it is exterior gyp or concrete. So, if you penetrate low flutes, you aren't penetrating a "membrane"...[purely speculative from this side of the internet...ymmv
]
proto
Dec 22, 23 1:03 pm
this one? yeah, fire away!
b3tadine[sutures]
Dec 21, 23 7:04 pm
A couple of things. Look at the existing building codes. Second, you can scrape of fire proofing, as long as they patch it back, I'm presuming it's cementitious. Firestopping.
I need to design a partition wall in an existing type 1a building with a fire rated roof. The partitions need to be braced to the underside of the metal decking of the ceiling/roof assembly. Is it ok to penetrate the existing assembly with screws?
What about bracing to a fireproofed beam?
Thank you
What dose the UL listing for the existing assembly say is allowed?
I'd probably ask your AHJ what they think will be allowed. You'll need that in writing when your special inspection is done.
Well it’s existing. I suppose I should find a similar ul. I can’t really tell what the assembly is besides being able to see the underside of deck
Thank you
You bet! Good luck with this. I know it's a pain to deal with.
These are the reasons why i still like going to archinect. Genuinely interesting but very non-sexy question. Thx! (Also more of this type of stuff)
Page 64 shows screw size and spacing for the rated assemblies, but it's for the face screws; I don't think there's a rule when you are attaching a partition if said partition will also be rated.
https://www.usg.com/content/da...
agreed...the tested assembly involves the required fastening. So, unless you're violating the assembly by removing required fasteners (or other materials), you should be good adding fasteners to that structure
I don't think additional fasteners violate the fire rating of the existing protected roof, unless they are wood pegs (or other weird thing) or somehow create voids/interruptions in the rated roof assembly
Typically that is correct. It all depends on the rated assembly and the number / size of the fasteners though. I know of several 2 hour assemblies that have requirements for penetrations of any type (including fasteners) that need to be sealed with fire caulk.
This wouldn’t be a rated partition..
We always include typical details for these situations. Usually for a non-rated assembly head detail at a rated assembly, we specify a slotted top track without issue about fastener spacing. It's not like it's adding new loads from underneath that could reduce the performance of the steel deck. Head details at rated gypsum membrane ceilings are another thing and far more complicated.
It’s not that it’s adding a load from beneath, just the fact that you are penetrating the membrane of the assembly…
are there other devices screwed to u/s of existing deck such as lights and carrying channels? How are those fasteners treated?
what membrane?
The fire protection membrane
JLC, not sure how it’s down south, but membrane is what we refer to when detailing fire separations made of gypsum sheets. At least that’s how my code calls them.
this is what membrane means "down south" - https://www.merriam-webster.com/dictionary/membrane
and this is how the 2021 IFC confuse the terms and doesn't really define what a membrane is
It’s not that it’s adding a load from beneath, just the fact that you are penetrating the membrane of the assembly…
Yes there are other things screwed in, I didn’t notice any fire caulk
"fire caulk" is primarily for smoke sealing. Side note, seach the forum for the classic "show me your caulk" discussion.
Fire caulking is only required on rare occurrences for certain types of assemblies. Hence why you need to find an assembly similar to the existing ceiling. Realistically you won't need to worry about the fasteners penetrating the membrane of the rated assembly.
It’s a typical steal frame metal deck system. I’m thinking ul902
my guess is the steel deck itself is not adding much value to the fireproofiness of your existing condition, whether what's above it is exterior gyp or concrete. So, if you penetrate low flutes, you aren't penetrating a "membrane"...[purely speculative from this side of the internet...ymmv ]
this one? yeah, fire away!
A couple of things. Look at the existing building codes. Second, you can scrape of fire proofing, as long as they patch it back, I'm presuming it's cementitious. Firestopping.