Fire Rating UL v other

[dcarr82775]

I was recently told by an architect that if you are using a fire rated assembly other than UL rated assmeblies you need to de-rate the load capacity by 20%. I am in the US, and have not heard of this before. I found references to some things in Canada, but that is it. Anyone heard of this before?

 

[KootK]

My experience of if it is only in Canada. I never encountered it in the US. That being said, it's apparently to do with the difference between LRFD and ASD methodologies so, logically, it would affect US ratings the same way. Cross your fingers that you don't have to deal with this. It's a terrible pain.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[KootK]

And the issue we have in Canada also applies to UL assemblies. Your architect may well be thinking of something entirely different.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[dcarr82775]

That is what I gathered. Does Canada not allow ASD wood anymore? For whatever reason I do LRFD for everything except wood which I stubbornly insist on doing with ASD so the funky conversion factor doesn't enter the equation.

 

[jike]

I am in the US and have always used UL ratings. I have never heard of someone using other than UL ratings.

There are some load reductions in joist capacities for UL ratings with spray on fireproofing but the loads are listed in various UL assemblies. Could this be what he is referring to? Get a reference from him......

 

[KootK]

Yeah, we're LRFD for wood nowadays.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[XR250]

What a pain using LRFD for wood. Actually, what a pain using LRFD period. I only use it for concrete.