When steel RSC, IMC or EMT raceways are used to penetrate a fire-resistance-rated assembly of concrete or masonry, the International Building Code (IBC) allows the annular space to be filled (sealed) with cement, mortar, or grout instead of having to use a listed firestop system. This is an inexpensive and readily available alternative that ensures that the fire-resistance rating of the penetrated assembly is not degraded.
In summary, because steel raceways withstand fire. Steel conduit is the ideal choice for applications in places of assembly:
◆ Galvanized steel RSC, IMC and EMT are considered non-combustible by the building codes.
◆ Steel raceways were still intact after a UL four-hour ASTM E119 test at near 2000 F.
◆ Does not add to fuel load or flame spread.