The water pressure and flow rate at the most unfavorable point of the indoor hydrant system do not meet the requirements of GB 50974, and effective firefighting cannot be achieved in the event of a fire.
The indoor hydrant system is a fundamental component of a building's fire protection systems and directly affects the firefighting capability in the early stages of a fire. GB 50974-2014 "Technical Code for Fire Water Supply and Hydrant Systems" is the most core standard reference, providing comprehensive provisions on fire water sources, water supply facilities, hydrant layout, pipe design and system control. GB 50016-2014 Section 8.2 specifies the scope of application for hydrant systems, and GB 55036-2022 consolidates the key mandatory clauses.
Regarding fire water sources, the capacity of the fire water tank should meet the total fire water consumption during the fire duration. For Class I high-rise public buildings, the fire duration shall be no less than 3 hours; for Class II high-rise public buildings, no less than 2 hours. Fire pumps should be provided with standby pumps, one duty and one standby, with the head and flow rate calculated and determined based on the firefighting requirements of the most unfavorable hydrant.
For hydrant layout, the spacing between two adjacent hydrants on the same floor shall not exceed 30 m for high-rise buildings or 50 m for other buildings, and the protection radius shall not exceed 25 m. The hydrant outlet pressure shall not exceed 0.50 MPa; when greater than 0.70 MPa, a pressure reducing device shall be installed. The effective water column of the fire nozzle shall be no less than 13 m for high-rise buildings and no less than 10 m for other buildings. The indoor hydrant pipe network should be arranged in a loop to ensure two-way water supply.
Regarding pipe materials, buried sections shall use ductile iron pipes or steel wire mesh skeleton plastic composite pipes, and above-ground sections shall use hot-dip galvanized steel pipes with grooved or flanged connections. The loop pipe network should be provided with sectional valves at spacing not exceeding 40 m. Pressure testing includes a strength test at 1.5 times the working pressure with a minimum of 0.60 MPa and a tightness test at the working pressure.
Monthly inspections shall check the hydrant appearance, valve flexibility, and the integrity of hoses and nozzles. Quarterly, water flow tests shall be conducted at the most unfavorable hydrant to measure pressure and flow. Every six months, lubricate the hydrant valve stems. Annually, test the fire pump flow and pressure. Every three years, conduct a comprehensive hydrostatic test of the pipe network. Common issues include obstructed hydrant cabinets, mismatched hose couplings, seized valves, non-interlocking pumps, and prolonged water absence in the pipe network.
The hydrant cabinet shall be installed with the center of the outlet 1.1 m above the floor. Firestop sealing shall be provided behind the cabinet to prevent fire spread along the pipe shaft. Fire dampers shall be installed where pipes penetrate fire compartments. The fire pump room should be provided with drainage facilities to prevent pump flooding. A test hydrant shall be installed on the roof for periodic testing. Hydrant buttons should start the pump directly and should not be routed through the alarm system. The system cost is approximately 5 to 10 RMB per square meter for residential buildings and approximately 10 to 20 RMB per square meter for public buildings.
For hotel buildings, the indoor hydrant system also requires consideration of zoned layout in guest room areas and public areas. The hydrant spacing in guest room corridors shall ensure that the effective water columns of two nozzles can simultaneously reach any point indoors. The decorative treatment of hydrant cabinets should meet aesthetic requirements, with cabinet doors using recessed concealed door design with an opening angle of no less than 160 degrees. Daily maintenance and annual inspection of the hydrant system should form complete archival records, including pump test data, pipe network pressure records, and hydrant inspection cards. It is recommended that the hotel engineering department conduct monthly inspections of the hydrant system and keep records, and annually commission a professional fire inspection agency to conduct a comprehensive inspection and issue a report. Automatic inspection records of fire pumps should be retained for no less than one year to facilitate traceability and analysis of system operation trends. After modification or repair of the hydrant system, hydrostatic testing and interlocking tests should be re-conducted to ensure system function is restored to the design state.
Hydraulic calculation of the hydrant system is the core technical aspect of system design. The static pressure at the most unfavorable hydrant shall not be less than 0.07 MPa; when the building height exceeds 100 m, it shall not be less than 0.15 MPa. The head calculation of fire pumps should consider the geometric height difference, pipe friction losses and local losses; local losses may be estimated at 20% to 30% of friction losses. Pipe diameter selection should control flow velocity below 2.5 m/s to ensure hydraulic balance. Pressure reducing valves should be calculated by zone, and the pressure before each pressure reducing valve should not exceed 1.20 MPa. The pressure fluctuation after the pressure reducing valve shall not exceed ±0.05 MPa. The construction difficulty of the hydrant system lies in the tightness test and flushing of the pipe network; the flushing velocity shall not be less than 1.5 m/s until the effluent is clear. The interlocking commissioning of the hydrant system is a key step in verifying system function, including comprehensive testing of three methods: hydrant button pump start, remote pump start from the fire control room, and local pump start at the pump room. In the maintenance management of the hydrant system, special attention should be paid to winter freeze protection; pipe insulation should be intact, and the end test valve should have insulation measures. Valves of the hydrant system should be in the normally open position with lead seals or locking devices to prevent misoperation. Through sound system design, strict construction and installation, and standardized maintenance management, ensure that the hydrant system can perform its due firefighting role in a fire.
Hydraulic calculation of the hydrant system is the core technical aspect of system design. The static pressure at the most unfavorable hydrant shall not be less than 0.07 MPa; when the building height exceeds 100 m, it shall not be less than 0.15 MPa. The head calculation of fire pumps should consider the geometric height difference, pipe friction losses and local losses; local losses may be estimated at 20% to 30% of friction losses. Pipe diameter selection should control flow velocity below 2.5 m/s to ensure hydraulic balance. Pressure reducing valves should be calculated by zone, and the pressure before each pressure reducing valve should not exceed 1.20 MPa. The pressure fluctuation after the pressure reducing valve shall not exceed ±0.05 MPa. The construction difficulty of the hydrant system lies in the tightness test and flushing of the pipe network; the flushing velocity shall not be less than 1.5 m/s until the effluent is clear. The interlocking commissioning of the hydrant system is a key step in verifying system function, including comprehensive testing of three methods: hydrant button pump start, remote pump start from the fire control room, and local pump start at the pump room. In the maintenance management of the hydrant system, special attention should be paid to winter freeze protection; pipe insulation should be intact, and the end test valve should have insulation measures. Valves of the hydrant system should be in the normally open position with lead seals or locking devices to prevent misoperation. Through sound system design, strict construction and installation, and standardized maintenance management, ensure that the hydrant system can perform its due firefighting role in a fire. When modification works of the hydrant system are carried out during hotel operation, special attention should be paid to the impact on normal operations. The modification plan should be implemented in zones and sections to minimize water supply interruption to guest rooms. A detailed temporary water supply plan should be formulated before modification construction to ensure that fire protection is not interrupted during the modification period. After repair and modification of the hydrant system, a pressure stabilization test of no less than 24 hours and interlocking tests should be conducted to ensure system function is restored to the design state. The annual inspection report of the hydrant system should include static and dynamic pressure test data of the most unfavorable hydrants in each zone, flow-head performance curve test data of fire pumps, and complete records of system interlocking tests.
Renovation work on the fire hydrant system during the hotel's operational period requires particular attention to its impact on normal operations. The renovation plan should be implemented in zones and phases to minimize water-supply interruptions to guest rooms. A detailed temporary water supply plan should be prepared before renovation construction to ensure that fire protection is not interrupted during the renovation period. After the repair and renovation of the fire hydrant system are completed, a pressure stabilization test and linkage test of no less than 24 hours should be conducted to ensure that system functions are restored to the design state. The annual inspection report of the fire hydrant system should include the static pressure and dynamic pressure test data of the fire hydrants at the most unfavorable points in each zone, the flow-head performance curve test data of the fire pumps, and complete records of the system linkage test. The annual inspection of the fire hydrant system should be entrusted to a qualified fire inspection agency, and the inspection data should be compared and analyzed with historical data to identify deterioration trends in system performance. The maintenance and management of the fire hydrant system should also focus on water level protection for fire reservoirs and tanks. The water level of the fire reservoir should be maintained above the design water level, and the makeup water device should be capable of automatic makeup. The water level of the fire tank should be maintained within the effective volume range, and the overflow pipe and drain pipe of the tank should be unobstructed. The cleaning cycle of fire reservoirs and tanks should not exceed six months, and the water quality test after cleaning should comply with fire water standards. The insulation facilities of fire reservoirs and tanks should be intact and effective in winter to prevent water freezing. Intelligent management of the fire hydrant system is also an important means of improving management efficiency. The intelligent inspection device of fire pumps can automatically perform low-frequency inspections according to preset procedures and record pump operating data. The pressure monitoring system of the fire pipeline network can monitor pressure changes in each zone of the network in real time. The electronic tag system of fire hydrant cabinets can enable information-based management of fire hydrant equipment. The intelligent maintenance platform of the fire water system can integrate equipment operating data, inspection data, and repair data, and identify patterns and problems in system operation through big data analysis.
Renovation work on the fire hydrant system during the hotel's operational period requires particular attention to its impact on normal operations. The renovation plan should be implemented in zones and phases to minimize water-supply interruptions to guest rooms. A detailed temporary water supply plan should be prepared before renovation construction to ensure that fire protection is not interrupted during the renovation period. After the repair and renovation of the fire hydrant system are completed, a pressure stabilization test and linkage test of no less than 24 hours should be conducted. The annual inspection report of the fire hydrant system should include the static pressure and dynamic pressure test data of the fire hydrants at the most unfavorable points in each zone and the flow-head performance curve test data of the fire pumps. Intelligent management of the fire hydrant system is also an important means of improving management efficiency. The intelligent inspection device of fire pumps can automatically perform low-frequency inspections according to preset procedures and record pump operating data. The pressure monitoring system of the fire pipeline network can monitor pressure changes in each zone of the network in real time and automatically issue an alarm when pressure anomalies are detected. The electronic tag system of fire hydrant cabinets can enable information-based management of fire hydrant equipment, and inspectors can record equipment status and inspection results by scanning codes. The intelligent maintenance platform of the fire water system can integrate equipment operating data, inspection data, and repair data, identify patterns and problems in system operation through big data analysis, and provide data support for optimizing maintenance strategies. Intelligent management can improve the management efficiency of the fire hydrant system and reduce manual inspection costs.