Knowledge

Home > Knowledge > Content
Fire Pump Selection Guide!
Feb 10, 2018

Most fire water supply fire water, all need fire pump to pressure, to meet the fire in the water pressure and quantity requirements. The failure of the pump due to improper setting and maintenance will inevitably affect the fire fighting and rescue, causing unnecessary loss.

Fire pump and Living water pump and production water pump compared to the performance of higher requirements, but the current norms in China's fire pump performance and testing requirements do not make more detailed special provisions, resulting in the selection of fire pump is not available to investigate, there are a variety of problems. The United States NFPA20 "life safety norms" on fire pump performance requirements are: the maximum flow of fire pump should be the design value of 150%, the head is not less than the selected work point head of 65%, close the pump when the head is not more than the selected work point head of 140%, the pressure-regulating pump flow for 1-2l/s The head is 1.1-1.2 times times the lift of the fire pump.

At the same time, the provisions of the fire pump outlet pipe should be set to measure flowmeter, flowmeter should be able to test the selected flow of water pump 175%, fire pump in the outlet pipe should be set in diameter greater than 89mm pressure gauge. It is suggested that the Customs Department should refer to the United States standard for the design and selection of fire pumps in China, so as to provide a more specific and specific requirement for the selection and detection of fire pumps.

NFPA20 the performance of the fire pump is as follows: Pump out flow for the selected work point of 150% of the flow, its head is not less than the selected work point of the head of 65%, close the pump when the head is not more than the selected work point head of 140%. It is actually stipulated that the pump performance curve is a smooth curve. Our country standard has no detailed stipulation to the fire-fighting water pump, causes the fire-fighting water pump's selection to have many exits. It is recommended that designers refer to the NFPA20 in the design.

"Gao" and "regulations" on the performance of Fire pumps no test requirements, NFPA20 specified fire pump in the outlet pipe to set the measurement flowmeter. Flowmeter should be able to test the selected flow of water pump 175%, fire pump in the outlet pipe should be set in diameter greater than 89mm pressure gauge, so that after the installation of water pump can be fully tested the performance of the pump in order to know whether the design requirements can be met. It is recommended that designers consider this problem in their design.

Fire-fighting water supply system is the pressure of the system at ordinary times to maintain the pump, the system plays a monitoring role and the system has automatic control function. Pressure regulator pump can be determined according to the pressure of the system, the general pressure regulator pump can be determined according to the system pressure, general pressure regulator pump than the main pump high 0.1mpa-0.2mpa, or pressure-stabilized pump 1.1 times times-1.2 times times. But for the steady flow of the pump to determine the different argument. "Gao" 7th. 4.8 pressurization facilities should comply with the following provisions: Fire hydrant water supply system should not be greater than 5l/s, the automatic sprinkler system should not be greater than 1l/s. United States NFPA20 "Standand for the installation of Centrifug Al Fire Pumps" (1996 Edition) regulated pump (pressure Maintenan pumps/jocey Pumps The flow of/make-up pumps is not less than the amount of leakage under normal system conditions, and the pressure should be sufficient to maintain the pressure required by the system. It is clear that China stipulates the limit of the flow of the regulator pump, while the United States stipulates the lower limit of the pump. Our country's pressure regulator pump flow set requirements are able to meet 1 fire units of water consumption, the United States is the system leakage.

Water leakage of automatic sprinkler system according to the national "Heating and sanitary engineering construction and Acceptance Code", article 3.15 stipulates: Hydraulic test, 10min pressure drop is not greater than 0.05MPA. The test pressure is then lowered to the working pressure for appearance inspection, so as not to be missed. Code for construction and acceptance of automatic sprinkler system 6th. 2.3 The test point of the water pressure test should be set at the lowest level of the system pipe NET, when the pipe net is injected, the air of the pipe net should be discharged, and the pressure should be slowly boosted to reach the test pressures, the voltage regulator 30min, the visual pipe network without leakage, no deformation, And the pressure drop is not greater than 0.05MPA. "Code for construction and acceptance of water supply and sewerage pipelines" gb50268-97 10th 2.13 stipulates that the allowable seepage quantity of DN100 pipe is 0.28L (min km), and the allowable seepage quantity of DN150 pipe is 0.3L (min km). Obviously, if the pipeline construction reaches the national standard, the leakage water of the system pipe network is very small. The author himself has observed two completed works, the leakage of water from the indoor piping mainly at the interface of the pipeline, and the leakage of water from the test drainage valve and the water pump outlet check valve which is in contact with the atmosphere. The capillary action at the interface of the pipeline is generally not a water droplet, and much evaporation in the air. One end of the contact with the atmosphere valve leakage is very easy to observe, the timely closure or replacement of the valve is not a problem. Pump export check valve due to shut down and into the pool backwater, this phenomenon is not easy to observe, is the system leakage of water leak a major hidden danger. For example, a project to select the pressure regulator pump flow for 1.33l/s, the regulator pump for a long period of time to run also does not reach the set pressures, the inspection is the pump export check valve is not strictly closed to the pool leakage, replace the check valve, the regulator pump normal work, and a few days to start. This indicates that the system is rarely leaking, and is almost negligible.

According to the investigation of domestic and foreign regulator pump flow of more than 0.5l/s-2.0l/s, when the system without pressure can stop pump has water hammer phenomenon. In view of the pressure regulator pump on the system has the monitoring and automatic control function requirements. We recommend that the flow of pressure-stabilizing pumps for 1.0l/s-2.0l/s, the main pump is higher than the 0.1MPA-2.0MPA or 1.1 times-fold-1.2 times times the main pump. The best pressure regulator pump with a gas tank, if not set pressure tank, should be in the regulator pump controller for the article, so that in the stop pump is not due to the role of water hammer and frequently start.








Copyright © Nanjing Beite AC Equipment Co.,Ltd All Rights Reserved.Tel: +86-25-58866256