Durham fire companies were dispatched to the 1100 blk. of Broad St. for a reported fire in a service station at around 0815 hrs. (2/22). Upon arrival of E-2, heavy smoke was visible from the bay area. Quick size-up revealed a gas furnace, in the ceiling of the bays, on fire, extending to some stored materials. "Fast-attack" made with quick knockdown. Thorough check for extension as ladder cos. "open up" the bays. Fire extinguished with booster water. Units responding: E-2,5,10, L-2,11, Batt-2.