IMC Riser in Stairwell

[Coreyd1@optonline.net]

Does anybody know if you can run an exposed IMC run in a stairwell. I was told the NFPA says it will have to be covered with a 2 hr fire rated wall where ever exposed in the stairwell. Trying to avoid having to install fire rated enclosures around the conduit.

 

[JoeStillman]

I don't think you'll find anything in the NEC about this. It is a building code issue. If you are following IBC, that is where the 2 hr enclosure is required (I think its in the Egress Systems chapter.) Also, it doesn't matter if its EMT, IMC or RGS. You can use any wiring method that's legal for your occupancy, as long as it has 2hr separation.

You could wind up blocking the required width of the egress path by building a chase. That's why I always try to avoid running things in stairways when any other path is available.

By the way, the 2 hr separation is not required if the raceway is dedicated to equipment within the stairwell.

 

[eprice]

Does anybody know if you can run an exposed IMC run in a stairwell. I was told the NFPA says it will have to be covered with a 2 hr fire rated wall where ever exposed in the stairwell. Trying to avoid having to install fire rated enclosures around the conduit.

Is this a rated stairwell? What is the IMC run for? The IBC prohibits any penetrations into a rated stairwell that is not there to serve the stairwell. You could have penetrations into the stairwell for lighting in the stairwell for example, but a feeder to a panel or circuits serving other areas in the building shouldn't even be in the stairwell. If you enclose it with a 2 hr rated wall, the building inspector may be willing to consider it to be outside of the stairwell.

 

[jumper]

Here is the code section the others are referring to.

2012 IBC

1022.5 Penetrations.
Penetrations into and openings through interior exit stairways and ramps are prohibited except for required exit doors, equipment and ductwork necessary for independent ventilation or pressurization, sprinkler piping, standpipes, electrical raceway for fire department communication systems and electrical raceway serving the interior exit stairway and ramp and terminating at a steel box not exceeding 16 square inches (0.010 m2). Such penetrations shall be protected in accordance with Section 714. There shall be no penetrations or communicating openings, whether protected or not, between adjacent interior exit stairways and ramps.