Pressure Control Valve : A pilot-operated pressure-reducing valve designed for the purpose of reducing the downstream water pressure to a specific value under both flowing (residual) and nonflowing (static) conditions
NFPA 14 Standard for the Installation of Standpipe, Private Hydrant, and Hose Systems, 2000 ed. http://pozhproekt.ru/nsis/nfpa/NFPA14-2003.pdf, (Std: Instll of Stdpp, Prvt Hyd and Hose Sys - Amer) {182 NFC}