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The selection of fire pump is very important to the building fire control system. According to the fire statistics, the fire fighting of high-rise buildings failed, and the main cause of the fire was the lack of water and the low water pressure. The fire water supply system of the building mainly includes the outdoor fire water supply system and the indoor fire water supply system. The outdoor fire water supply system consists of four parts: water intake, water storage, distribution and water supply. The indoor fire water supply system is mainly composed of fire water supply source, fire fighting water supply equipment (mainly water pump), indoor fire water supply pipe network, indoor fire hydrant and other parts. Visible, whether outdoor or indoor fire water supply system, which can not be the main water supply equipment - water pump. And the water pump used for fire protection is called the fire pump.
Pay attention to the performance requirements of the type selection of fire pump
In order to meet the needs of fire protection, fire pumps should meet requirements in terms of structure, corrosion resistance, mechanical performance, vacuum sealing performance, continuous running performance and water diversion device.
(1) the characteristic curve of the fire pump should be slow to avoid the phenomenon that the pressure of the small flow and high lift and the pressure of the large flow are reduced.
(2) the pump body should have an arrow indicating the direction of rotation or a marked display of signs.
(3) the overflow surface of the pump should have corrosion resistance to the medium.
(4) the pump should be sealed test, during the test, the pump shell without leakage, sweating and other defects;
(5) the water pressure test should be carried out for the overflow parts of the pump. In the process of the test, the pump shell should not have defects such as cracks and deformation.
(6) the pump should have good vacuum sealing performance, and the vacuum landing value in 1min should not be more than 2.6kPa.
(7) the diversion device should comply with the following stipulations: the maximum vacuum degree of the water diversion device should not be less than 80kPa; the pump should carry out the test of water diversion time, and the time of water diversion shall comply with the regulation of Table L.
(8) the pumps used in the fire pump unit should be identified by the provincial and ministerial units, and in accordance with the relevant standards.
(9) the original motive of the original motive should be identified and accorded with the relevant standards, and the performance of the original motive should conform to the original requirement.
(10) the engine should have good starting performance at normal temperature. It should ensure the smooth start of the 5S, and the 20S should be able to make the pump reach the rated working condition.
(11) the flow rate of the fire pump unit should be more than 50% of the rated flow when the 6m pump unit has the rated pressure and the pressure at the rated pressure.
The above requirements should be taken into account in the selection of fire pump.
Need to pay attention to installation requirements for the selection of fire pump
In general, the selection of fire pump installation shall meet the following requirements: strong and self-locking device of fire pump shall not cause loosening due to vibration and water in the way; the fire pump, for high-rise buildings must use self filling type water to the fire water supply system to prevent overpressure measures, such as water hammer eliminator, safety valve or other pressure relief device is arranged in the pump outlet pipe; pump suction pipe, the outlet pipe should be arranged according to the following requirements:
(1) the water suction pipe of a group of fire pumps should not be less than two, in order to ensure that one of the damage, the rest of the water pipe can still pass all water use;
(2) each fire pump shall have independent suction pipe. When there are two or more than two working pumps, the standby pump can share a suction pipe with the working pump. At this time, the valve should be installed on the suction pipe, so as to control separately.
(3) the fire pump group shall have no less than two outlet pipes connected to the ring pipe network. When one of the pipes is overhauled, the remaining water output should still be able to supply all the water consumption.
(4) check valves, gate valves, test and check water release valves and pressure gauges should be installed on the outlet pipe.
The installation requirements of the fire pump selection process are also very important.
Test operation requirements for type selection of fire pump
After the installation of the fire pump, a continuous trial run test should be carried out, and the following requirements should be reached when the pump is tested.
(1) the pressure of the outlet of the pump must not be lower than the specified export pressure, and the flow must be in accordance with the required requirements.
(2) the outer surface temperature of the bearing seat shall not exceed 75 centigrade, and the temperature shall not exceed 350C;
(3) the bearing is sealed well, the leak phenomenon is wireless, and the packing seal is allowed to adjust.
(4) the vibration of the pump should be in accordance with the relevant regulations.
When the fire pump continuous operation test, also called the prime mover and the power output device should meet: normal, no Water Leakage, leakage phenomenon; the engine water temperature and oil temperature should be consistent with the requirements of the original machine; the temperature of lubricating oil power output device should be lower than the maximum allowable working temperature of lubricating oil; bearing temperature power the output device shall not exceed 1000C; working voltage, the motor current and the bearing temperature should be within the allowable scope of work.
In addition, the fire pump group with engine as prime mover should carry out 10min overload test. During the test, the pump group should work normally without excessive vibration and leakage.
Determination of water pressure for type selection of fire pump
The influence of the fire pressure on the fire effect is also very important. If the water pressure is too small, the fire water will not reach the required height, which will bring great difficulties to the fire fighting.
The water pressure of fire hydrant at the hydrant of high rise building should be pressed by the press type.
Determining the selection parameters of fire pump for high rise buildings
The high-rise building fire pump for special use, pay attention to the differences between requirements and ordinary water pump fire pump in the selection, the selection should first determine the quantity and pressure of water fire required, then according to the fire characteristics according to the characteristics of the pump performance parameters table or graph to select the appropriate pump. Usually, the fire pump in high building can be selected according to the following requirements:
(1) the water quantity of the water pump should meet the requirements of the water supply.
(2) the lift of the pump shall meet the conditions of the fire flow and ensure the most unfavorable water.
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