2 hour rated floor assembly?

[palikona]

I’m designing a 5 unit sprinklered multi family building with parking garages on level 1 and living on levels 2 and 3. We need a 2 hour floor separation between the garage sprinklers (NPFA 13) and living (NfPA 13r). I’ve been searching USG and cannot find a 2 hour floor assembly for wood joist construction. Any advise on what to look at or a UL listing?

Thank you!

 

[TheCommish]

The supporting structure of the 2 hour rating also must meet the 2 hour rating

 

[BN4537]

You are trying to use actual 2x sawn lumber for a 2 hour horizontal assembly? I don't think there is such an animal as a listed assembly. If you find one, please post it here so I can keep it in my back pocket.

The last page of this document has one for I-joists, don't know if that can help or not. We know that solid lumber lasts longer than I-joists in a fire scenario, so maybe you can come up with something similar that an AHJ might accept for solid lumber.

This thread gets into the weeds on various topics related to floor assemblies but it is a good read: https://www.thebuildingcodeforum.co...e-to-allow-for-romex-wiring.35532/post-279778

 

[Paul Sweet]

Gypsum Association GA-600 has several 2-hour wood-framed floor/ceiling assemblies. The ones requiring proprietary gypsum board have 2 or 3 layers, the ones using generic Type X require 4 layers.

 

[BN4537]

You are trying to use actual 2x sawn lumber for a 2 hour horizontal assembly? I don't think there is such an animal as a listed assembly. If you find one, please post it here so I can keep it in my back pocket.

Never mind...

 

[palikona]

Thank you all, this is very helpful.

 

[BuildingOfficial89]

Gypsum Association GA-600 has several 2-hour wood-framed floor/ceiling assemblies. The ones requiring proprietary gypsum board have 2 or 3 layers, the ones using generic Type X require 4 layers.

I have several sticky notes in my copy. Quite useful.