Companies arrived o/s with heavy smoke pushing from a 2-1/2 story twin dwelling. Crews led off with 1-3/4 to the front. Search & Rescue crews entered the bldg and were forced to eveacuate through 2nd floor rear windows. 3 F/F's were transported with non life threatening injuries. Fire had flashed over in the 1st floor and was running up the stairs to the 2nd floor. All crews were evacuated from the bldg, and the 2nd alarm was requested. An exterior attack was ensued until all visible fire was knocked and it was safe for f/f's to return to an interior attack to open up and hit hot spots. umerous handlines were in svc.