Working on a concrete/steel project. Owner doesn't want to see fireproofing, but project needs a fire rating of the floor and supporting structure. (1 hour rating req'd). The strux engineer believes that he can come up with a fire rating for exposed (un protected) steel. I think what he thinks he can do is to determine at what point the steel will lose strength, and if it's more than 1 hour, then we don't need to fire rate the steel.
I'm very uncomfortable w/this, but honestly, that's the same thing that spray fireproofing is doing - eventually the steel will lose strength in the fire, we are just delaying it until after 1 hour.
This might end up being a non-issue - he might not be able to make his calcs work.
Have you ever done something like this, or even heard of it? It's a new one for me.
The project is a large garage (Storage use group) with a tiny apartment (residential use group). 1 hour rating required. The garage is 2 level, apartment on the upper level. We get a 1 hour rating out of the concrete/steel deck floor, so it's just the beams I'm worried about. I've offered intumescent paint as an option, but the owner wants nothing on the beams.
I'm also concerned because I'd imagine that anything that's stored in the garage (IE: gasoline in the tanks of cars) can potentially burn hotter and faster than typical fire loads. Although I haven't researched it yet, I know they make "high temp rise" spray applied fire proofing. Not sure this is the correct application or no.
------------------------------
David Sisson AIA
Architect
David Sisson
Providence RI
------------------------------