Pressure-Restricting Device : A valve or device designed for the purpose of reducing the downstream water pressure under flowing (residual) conditions only
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}