Firestop intumescent foam used to fill the annular space created by pipes and cables penetrating through fire-rated construction. No mineral wool backing required, so 3M Fip 1-step firestop foam installation is up to three times faster. Not runny, won’t run or sag in horizontal or vertical applications – consistent expansion rate. 3M FIP 1-Step Fire Barrier Rated Foam is similar to 2-step epoxy sealants, but with only 1 step.