Introduction and Interpretation of the New GB 6245 National Standard.One of the most pivotal changes in GB 6245-2025 is the requirement that diesel engine power must cover every point on the pump performance curve. The exemption clause for 1.5 times flow rate in the old regulation has been removed, meaning that any overload at a single operating point will create safety hazards and result in acceptance failure. The industry refers to this as “no-overload” operation. PumpMac takes you to an in-depth interpretation of the new regulation requirements.
GB 6245—2025
c) Bearings and anti-reverse mechanisms; if the drive is a diesel engine, a hollow shaft right-angle gearbox with an anti-reverse mechanism shall be used, or a solid shaft right-angle gearbox with an additional thrust bearing and anti-reverse mechanism;
d) A corrosion-resistant suction filter screen shall be installed at the suction inlet. The total area of the screen holes shall not be less than 4 times the area of the suction inlet, and the diameter of the screen holes shall not be larger than the minimum dimension of the pump’s flow passage.
6.2 Material Requirements
6.2.1 The pump body and pressure components shall be made of metal alloy materials. The shaft shall be made of at least 20Cr13 stainless steel or equivalent corrosion-resistant metal materials; or if the shaft is made of carbon steel, the shaft sleeve shall be made of corrosion-resistant metal materials.
6.2.2 Impellers, impeller seals, pump body seals, cones, wear rings, water seals, packing glands, mechanical seals, packing shafts, water bearing sleeves, retaining sleeves, intermediate sleeves, pressure reducing sleeves, seal pressing covers, cover nuts, shaft bushings, impeller nuts, and drain plugs, etc., shall be made of corrosion-resistant materials.
6.2.3 The pump’s radial balance device shall be made of corrosion-resistant materials.
6.3 Appearance Quality
6.3.1 All cast parts shall be free from obvious burrs, bubbles, sand holes, etc. Castings shall be free from shrinkage holes and looseness.
6.3.2 The pump body and various outer casings, tanks, etc., shall be painted with R03 bright red paint specified in GB/T 3181—2008 (except for stainless steel casings). The appearance of the paint layer shall be smooth and uniform in color.
6.4 Main Technical Parameters
6.4.1 Main Technical Parameters of Fixed Fire Pump Sets
6.4.1.1 The rated pressure (Pₙ) of fixed fire pump sets shall not be less than 0.2 MPa.
6.4.1.2 When the suction lift is 1 m (for deep well fire pump sets, when the minimum submergence depth is met), the rated flow (Qₙ) and rated pressure (Pₙ) requirements shall be met, and the shut-off pressure shall not exceed 1.08 times the rated pressure (Pₙ).
6.4.1.3 When the suction lift is 1 m (for deep well fire pump sets, when the minimum submergence depth is met), the flow rate is 1.5Qₙ, and the shut-off pressure shall not be less than 0.65Pₙ.
6.4.1.4 When the suction lift is 1 m (for deep well fire pump sets, when the minimum submergence depth is met), the maximum shut-off pressure shall not exceed 1.4Pₙ.
6.4.1.5 When the suction lift is 1 m (for deep well fire pump sets, when the minimum submergence depth is met), the pump’s dead-head pressure shall not be less than 98% of the maximum shut-off pressure.
6.4.1.6 When the inlet is always positive pressure, the pump’s power curve shall show an inflection point.
6.4.2 Main Technical Parameters of Fixed Pressure-Stabilized Fire Pump Sets
6.4.2.1 The rated pressure (Pₙ) of fixed pressure-stabilized fire pump sets shall not be less than 0.2 MPa.
6.4.2.2 When the suction lift is 1 m (for deep well fire pump sets, when the minimum submergence depth is met), the rated flow (Qₙ) and rated pressure (Pₙ) requirements shall be met, and the shut-off pressure shall not exceed 1.08 times the rated pressure (Pₙ).
6.4.2.3 When the suction lift is 1 m (for deep well fire pump sets, when the minimum submergence depth is met), the maximum shut-off pressure shall not exceed 1.4Pₙ.
6.4.2.4 When the suction lift is 1 m (for deep well fire pump sets, when the minimum submergence depth is met), the pump’s dead-head pressure shall not be less than 98% of the maximum shut-off pressure.
6.4.2.5 When the inlet is always positive pressure, the pump’s power curve shall show an inflection point.
6.5 Mechanical Performance
The mechanical performance of the pump shall comply with the provisions of 5.5.
GB 6245—2025
6.9.6 .6The outlet pipe diameter of the heat exchanger shall be larger than the inlet pipe diameter. The outlet shall be connected to a visible joint, and no valves shall be installed in this section of the pipeline.
6.9.6.7 The design of the heat exchanger shall ensure that when the inlet air temperature at the air cleaner is at least 49 °C, the maximum allowable operating temperature of the diesel engine is still not exceeded.
6.9.7 Diesel Engine Exhaust Port and Exhaust Pipeline
Flexible corrugated connections (welded or seamless) shall be used between the diesel engine exhaust port and the exhaust pipeline. The size of the exhaust pipeline shall not be smaller than the exhaust port size of the diesel engine. The internal part of the exhaust pipeline shall be wrapped with high-temperature-resistant thermal insulation materials.
6.9.8 Diesel Engine Power
6.9.8.1 The rated power shall be clearly marked on the diesel engine nameplate. Under standard conditions (atmospheric pressure 100 kPa, ambient temperature 25 °C, relative humidity 30%), the rated power of the diesel engine shall not be less than the maximum shaft power of the pump.
6.9.8.2 When used in non-standard environments, the diesel engine power shall be corrected, and the corrected diesel engine power shall meet the requirements of 6.9.8.1.
6.9.9 Connection between Diesel Engine and Pump
6.9.9.1 The installation of the coupling shall meet the manufacturer’s requirements, and the transmission shaft shall prevent unnecessary forces from acting on the diesel engine or gearbox.
6.9.9.2 The diesel engine shall be connected to the deep well pump through a flexible coupling and a right-angle gearbox.
6.9.10 Start-up and Shutdown
6.9.10.1 The diesel engine shall have automatic and manual start-up functions. Manual start-up shall include manual start-up on the diesel engine’s control panel and control cabinet.
6.9.10.2 The diesel engine shall have good cold start performance, ensuring smooth start-up within 5 s and reaching the rated speed within 20 s.
6.9.10.3 Except for the overspeed trip device causing the diesel engine to shut down, the diesel engine fire pump set shall not shut down automatically and can only be shut down manually.
6.9.11 Operation Procedures and Warnings
6.9.11.1 The diesel engine fire pump set shall have an operation procedure including detailed emergency operation steps.
6.9.11.2 On the diesel engine fire pump set, obvious warning and caution signs shall be provided at positions that pose a personal safety hazard or injury to operators.
6.9.12 Manual Operation Function
In case of failure of the automatic control function, the diesel engine fire pump set shall still be operable manually to ensure normal operation.
6.9.13 Monitoring Functions
The diesel engine fire pump set shall have at least the following monitoring functions:
a) Diesel engine speed;
b) Operating hours timing;
c) Diesel engine oil pressure;
d) Diesel engine coolant temperature;
e) Battery voltage.
GB 6245—2025
11.2.4 Test of Main Technical Parameters
11.2.4.1 Test Conditions
Test environmental conditions, test equipment, test devices, and measurement uncertainty shall comply with the relevant provisions of 11.1.4.1~11.1.4.4.
11.2.4.2 Test Methods
11.2.4.2.1 Performance Test
Measure the outlet gauge pressure difference and inlet gauge pressure difference (except for deep well fire pump sets). Determine the relationship between the pump’s net pressure, shaft power, efficiency, and flow through tests. The test shall be carried out sequentially from the operating condition with the minimum shaft power, and simultaneously measure the flow rate, inlet pressure (except for deep well fire pump sets), outlet pressure, speed, pump shaft power or torque. During the test, the speed shall be within ±10% of the pump’s rated speed. The test duration shall be long enough to obtain repeatable results.
11.2.4.2.2 Maximum Power Test
When the inlet is always positive pressure, start from the dead-head point, gradually open the outlet valve and observe and record the change of the pump set’s shaft power until an inflection point appears.
11.2.4.3 Test Results
Test data shall be corrected according to standard conditions and rated speed to determine whether the test results meet the provisions of 6.4.
11.2.5 Mechanical Performance Test
The test shall be carried out according to the method in 11.1.5 to determine whether the test results meet the provisions of 6.5.
11.2.6 Coupling Test
11.2.6.1 Calculate and check the coupling service factor to determine whether the inspection results meet the provisions of 6.6.1.
11.2.6.2 Start the fire pump set, adjust to the rated operating condition, run for 30 s, then stop. Repeat 20 times, 10 times before and after the performance test. Determine whether the test results meet the provisions of 6.6.2.
11.2.6.3 Visually inspect the coupling protection device to determine whether the inspection results meet the provisions of 6.6.3.
11.2.7 Continuous Operation Performance Test
The fire pump set shall operate for 4 h under rated operating condition and 0.5 h under 1.5 times the rated flow. Each continuous operation test shall not be interrupted. During the continuous operation test, measure the outer surface temperature of the pump bearing housing (except for deep well fire pump sets) every 15 min. The pump set shall also measure the diesel engine outlet water temperature, transmission mechanism lubricating oil temperature, outer surface temperature of the bearing housing, motor bearing housing outer surface temperature (if applicable); simultaneously measure the flow rate, outlet pressure, inlet pressure (except for deep well fire pump sets), and speed. Vibration measurement shall be carried out according to the test method specified in GB/T 29531. Determine whether the test results meet the provisions of 6.7.
11.2.8 Other Requirement Tests for Electric Motor Fire Pump Sets
11.2.8.1 Check the relevant inspection report of the motor to determine whether the inspection results meet the provisions of 6.8.1.
11.2.8.2 Visually check the motor nameplate rated power and compare it with the pump set’s maximum shaft power test result to determine whether the inspection results meet the provisions of 6.8.2.
11.2.8.3 The test method for the control cabinet of the electric motor fire pump set shall be in accordance with Appendix B.
About Us
PumpMac is a sub-brand of EMAC Group, focusing on water pump applications. Based on Cummins, Deuze, Caterpillar, Perkins, Weichai, CAMC and SDEC engines, PumpMac integrates a series of pump components to provide pumps with power systems, fire pumps, water pumps, intelligent fire modules, control assemblies, etc. Professional one-stop solution. Since the establishment of the PumpMac brand, it has closely cooperated with Cummins, Deuze, Caterpillar, Perkins, CAMC and other brands and represented its products. It has its own brands in the fields of pump power packs, fire pump sets, pump sets, and pump components. The products are widely used in Fire protection, petrochemical explosion-proof, construction site, mine pumping, underwater operation, factory water supply and drainage, agricultural irrigation, urban drainage, municipal emergency repair, emergency rescue and other scenarios, to provide customers with reliable and economical combined solutions.
