Layout requirements for suction pipe of fire pump
Fire pump suction pipe layout (ensure no leakage, no gas accumulation, no inhalation)
1. A set of fire pump, suction pipe should not be less than two, when one of the damage or maintenance, the rest of the suction pipe should still be able to pass all the fire water supply design flow;
2. Fire pump suction pipe layout should avoid forming air bags;
3. The submersion depth of the suction port of the fire pump should meet the requirements for safe operation of the fire pump at the lowest effective water level. The submersion depth of the bell mouth of the suction pipe at the lowest effective water level of the fire tank should be determined according to the water flow velocity and hydraulic conditions of the bell mouth of the suction pipe, but should not be less than 600mm. When cyclone preventers are used, the submerged depth should not be less than 200mm;
4. The suction pipe of the fire pump should be equipped with rising stem gate valve or butterfly valve with self-locking device, but when the non-stem valve is set, it should be equipped with opening scale and mark; When the pipe diameter exceeds DN300, the electric valve should be set;
5. When the diameter of the suction pipe of the fire pump is less than DN250, the flow rate should be 1.0m/s-1.2m/s; When the diameter is greater than DN250, it should be 1.2m/s-1.6m/s;
6. The arrangement of suction well should meet the requirements of smooth water flow, uniform flow rate and no vortex in the well, and should be convenient for installation and construction;
7. When the suction pipe of the fire pump passes through the fire pool, flexible sleeve should be used; When rigid waterproof sleeve is used, flexible joints should be set on the water pump suction pipe, and the pipe diameter should not be greater than DN150.
8. The suction pipe of the fire pump can be equipped with a pipeline filter. The water passing area of the pipeline filter should be 4 times larger than the water passing area of the pipeline, and the aperture should not be less than 3mm.
9. There should be no air bag and air leakage on the horizontal pipe section of the suction pipe of the fire pump. When reducing the diameter, the eccentric reducing pipe fittings should be used and the pipe top should be connected flat.