ABSTRACT
Should the sprinkler system cover less than 5,000 sq ft, system piping may be sized per National Fire Protection Association (NFPA) standards to conform to a pipe schedule that assigns a particular pipe size based on the number of sprinklers supplied by the pipe, which will vary based on the degree of hazard of the occupancy. More often, the pipe sizes are hydraulically designed, tailored to the specific occupancy being protected. There is a maximum square-foot area that each sprinkler system may protect within a structure, so for buildings covering a large expanse, there may be more than one sprinkler riser installed within. Each riser contains a controlling valve, pressure gauge, a water flow-indicating device for alarm purposes, and a main drain valve. The systems are normally designed so that all water from the system will drain back to the main drain valve, typically through a 2-in. angle valve that will discharge drainage water to the outside.
