At ~ 7:48 PM, Westmoreland 911 dispatched Station 20 (Murrysville VFC) to assist Station 86 (Trafford VFC) for an Automatic Fire Alarm (AFA) on Commerce Circle in Trafford, PA. Station 20 responded with Truck 20 (4 firefighters including Assistant Chief 20), with 5 firefighters (including Captain 20) on station standby. Westmoreland 911 also dispatched the following additional stations to support Station 86: Station 9 (Level Green VFC) and Station 1 (Larimer VFC). Engine 86 was first on scene, with Chief 86 establishing the command, and finding no smoke or fire coming from the structure. Upon Truck 20's arrival, Command 86 positioned Truck 20 to erect its 100 foot ladder in order to access the roof of the multi-storied building. Station 20 firefighters surveyed the structure's roof, and found no evidence of fire. Interior firefighter crews from Stations 86 and 9 found a broken sprinkler head which activated the AFA System. The interior crews stopped the water flow, and Command 86 released Truck 20 for return to service and station.