These requirements cover metallic pipe intended for use in water based fire protection systems for water distribution or valve trim applications. These pipes may be used in fire protection systems when installed in accordance with the following Standards: a) Standard for Installation of Sprinkler Systems, NFPA 13; b) Standard for Installation of Sprinkler Systems in Residential Occupancies up to Four Stories in Height, NFPA 13R; c) Standard for Installation of Sprinkler Systems in One- and Two- Family Dwellings and Manufactured Homes, NFPA 13D; d) Standard for Installation of Standpipe, Private Hydrants, and Hose Systems, NFPA 14; e) Standard for Water Spray Fixed Systems, NFPA 15; f) Standard for Installation of Foam-Water Spray Systems, NFPA 16; and g) Standard on Water Mist Fire Protection Systems, NFPA 750. Pipe is categorized by size, pressure rating, end configuration, (threaded or unthreaded) and wall thickness designation. Steel pipe is also categorized by the Corrosion Resistance Ratio (CRR).