A system that provides 1½ in. (40 mm) hose stations to supply water for use by trained personnel and 2½ in. (65 mm) hose connections to supply a larger volume of water for use by fire departments and those trained in handling heavy fire streams
NFPA 25 Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems, 2008 ed. https://law.resource.org/pub/us/cfr/ibr/004/nfpa.2 5.2002.pdf, (Std: Insp, Testing, and Maint of Wtr-Based Fr Prac Sys - Amer) {191 NFC}