Valve, Master Pressure Reducing : A pressure reducing valve installed to regulate pressures in an entire fire protection system and/or standpipe system zone
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}