NFPA 14 addresses standpipe systems that provide water supply to hose connections on each floor of high-rise buildings. Class I systems are for professional firefighters with large hoses (2.5-3 inches). Class II systems serve small hoses for initial firefighting attempts. Pressure must be 65-100 psi at hose connections to permit effective water discharge. Water supply is from municipal mains or rooftop tanks pressurized by pumps. Pressure relief valves prevent excessive pressure. System testing and inspection ensure reliability.