A fire-protective system of overhead pipes and outlet heads on a single main connection. There are two basic systems: a Wet System, in which the pipes are always filled with water so that a head can be immediately discharged, and a Dry System, in which the pipes are filled with air under pressure, with water flowing into the pipes with a drop in air pressure when the head is opened. The Dry System can have a separate early alarm to counteract the time delay with closed heads.