2-Hr Stud Wall framing w/ 2 layers 5/8" gyp 1

[CLTEng]

In reviewing a ClarkDietrich webinar it is noted that a 2 hour UL wall assembly that consist of cold-form stud framing with 2 layers of 5/8" gyp on each face of the stud must had stud framing designed only for 80% of the axial capacity. I'm trying to look for additional information with other sourced I have not really been able to find a good description of what would would cause this requirement...does any one have any insight?

Also, is anyone aware of any similar capacity reduction requirements for a 2 hour wood wall assembly with similar gyp installation? Is this reduction a possible cause of the heat transfer through the fasteners of the metal to metal connection?

Any insight or reference would be appreciated.

Thank you.

 

[dik]

I wasn't aware of the 80% capacity requirement... at fire? likely not much live load on the wall system. If dead load, then the reduced load factor should accommodate it

Dik

 

[Wallache]

Take a look at the particular UL assembly you are using, the reductions should be outlined there. If you are using IBC prescriptive fire requirements, take a look at Table 721.1(2), foot note 'm'.

 

[dik]

Thanks...

Dik

 

[CLTEng]

Thanks for the help on this Wallache.