Hi WTHall!

I went thru this same situation about 10 years ago.  Although the insurance inspectors were willing to let me get by with fireproofing and sheetrock (making the equivalent of a 2-hour enclosure around the conduit), the fellows from construction code enforcement were only willing to accept 4-hour construction as "equivalent protection" (i.e., still didn't meet code).  We had to put 4" of concrete around it.

Good luck with your situation!

Old Dave

Thanks for the response.

I forgot to mention that this conduit is running through the ceiling joists, about 10' above grade. Concrete doesn't seem like an option.  

wthall,

If the cable length is short it may be easier to replace it by a fire resistance/MI cable, otherwise you may use Endothermic Ceramic Fiber Blanket (manufactured by 3M), they claim that they have a standard design for 3-hour rated electrical system protection.
http://www.mmm.com/us/arch_construct/firestop/product/p_14.html

Concrete and MI cable are the only two solutions I'm aware of.  The MI cable does sound cheaper, but I wouldn't overlook the concrete option until you get pricing.

I have previously bought cable tray protection from a company in Houston (http://www.e-cats.com/procon/index.htm) that is capable of withstanding severe fire (including hydrocarbon fires).  You will need to watch out as wrapping power cables in any system may require uo to de-rate the cable to prevent it overheating.