The design of the pump room includes the selection of the location of the pump room, the design of the pool (including the bottom elevation of the pool, the effective water depth, the design of the inlet and outlet pipes of the pool, etc.), the selection of the pump type, the arrangement of the pump, the drainage ditch in the pump room, and the sump Design etc.
The following are the main points in the design process of the pump room:
1. Selection of the location of the pump room
The pump room is the core part of the entire building or the entire community, plant area, water supply, and fire fighting pipe network. The location of the pump room should not only be beneficial to the laying of water supply and fire fighting pipe network, but also not have noise impact on quiet rooms. Minimize the occupation of valuable buildings (such as shops and parking spaces). The domestic water supply pump house and the fire pump house should be built together, which not only saves land, but also facilitates maintenance management.
For a residential community, the pump room is often designed in the equipment room of the underground garage, combined with the generator room and other electrical and air-conditioning rooms in the same fire compartment. And the pump room should be as close as possible to the central location of the major water users or the entire community, which can reduce the length of the main pipe and reduce the head loss of the pipe network. The outlet of the pump room should be directly connected to the outdoors or directly to a safety exit. For example, the pump room located in a civil building should not be adjacent to the residential room or on the upper or lower floor, and the pump room should be located in a well-ventilated, non-freezing room.
The size of the pump room is determined by the layout of the living pool, fire-fighting pool and water pump set.
2. The design of the inlet, outlet and overflow pipes of the pool
Article 3.2.4B of "Code for Design of Building Water Supply and Drainage" GB50015-2003 2009 edition (hereinafter referred to as "Water Regulation"): The air gap between the low point of the inlet of the drinking water pool (tank) and the overflow edge should be equal to The diameter of the water inlet pipe shall not be less than 25mm, and may not be greater than 150mm. Another 3.2.4C: The amount of water from the drinking water pipe network to other water storage pools (tanks) for fire fighting, reclaimed water and rainwater reuse, the air gap between the low point of the inlet pipe and the overflow edge should not be less than 150mm. Therefore, there are often designs that only consider the provisions of 3.2.4B, and set the water inlet pipe of the fire pool at a position that is multiple of the pipe diameter above the overflow water level. This provision takes into account that pools used for fire fighting, reclaimed water and rainwater reuse are of lower quality than domestic drinking water, and the water in the pool is often not regularly cleaned or recirculated. The water in the pool will form stagnant water and breed bacteria. Therefore, although the diameter of the water inlet pipe of the fire pool is 50~100mm, the air gap with the overflow edge is still not less than 150mm.
The outlet pipe of the pool should be arranged as far as possible from the inlet pipe, and the position of the inlet and outlet should be used to make the water in the pool reach a favorable circulation, otherwise measures should be taken to prevent short circuits.
No valve shall be installed on the overflow pipe, and an insect-proof grid shall be installed at the outlet, and indirect drainage shall be adopted.
3. The setting of the sink, vent pipe and manhole in the pool
General reinforced concrete pools are equipped with suction troughs (wells), and most of the suction troughs (wells) are buried (that is, the suction trough is 0.8~1.0m deeper than the bottom of the pool). The effective volume of the suction tank (well) should be calculated according to the 3min design flow rate of the large water pump. And the size of the suction tank (well) should meet the installation requirements of the suction pipe of the pump.
vent pipes are often overlooked in the design of living pools and fire-fighting pools. The pipe diameter of the snorkel should be obtained from the large water intake or the large water output, and the pipe diameter and number of the snorkel should be calculated according to the large ventilation (generally no less than 2). The end of the vent pipe should be provided with an insect-proof grid.
Manholes should be installed in the pool, and climbing ladders should be installed near the manholes, and the location of the manholes should be as close as possible to the position of the water inlet float valve of the pool in order to maintain the water inlet valve of the pool.
4. Selection and arrangement of water pumps in the pump room
The general life pressurization equipment mostly uses frequency conversion equipment or overlapping (no negative pressure) equipment for water supply. When using variable frequency equipment, the main pump of the life pump set is selected according to the large second flow rate of the building (or partition) and the head of the unfavorable point. Moreover, the equipment of the variable frequency pump set on the market is complete, and the frequency conversion technology is also perfect.
But when using stacked equipment for water supply, it is often unclear how to choose the head of the equipment group. Because the point of superimposed water supply is energy saving, the business will also introduce to the designer that when selecting equipment, only the pressure required for the disadvantaged point of the building minus the municipal pressure can be used. However, according to the technical analysis of non-negative pressure equipment, there are two types of non-negative pressure equipment: water tank and non-water tank. When the non-negative pressure equipment with water tank is used, the water supply safety within a certain time should still be met when the municipal water is cut off. Therefore, the water supply pressure at this time should be determined according to the pressure required by the unfavorable water supply point of the building.
In the selection of fire-fighting pumps, designers often choose the fire-fighting pump to be used according to the calculated water consumption and head of the indoor fire hydrant or spray. There is no problem with this design in the specification, but there are difficulties and excessive investment in actual use and construction investment. If the water consumption and lift of the indoor fire hydrant and sprinkler are not much different, a spare pump can be shared, and the working capacity of the large fire pump can be used. In another case, the power of the fire pump is too large (such as 110Kw or above). In the electrical distribution design, the starting current of the water pump is 5-6 times larger than the working current, which invisibly increases the capacity of the generator . In this case, the use spare should be changed to the second use spare, and two half-flow pumps with the same head should be used instead of the large-flow fire pump.
In addition to meeting the distance between the pump sets and the distance between the pump sets and the wall specified in the specification, the arrangement of the water pump should also pay attention to the arrangement of the water pump not to hinder the use of the passage in the pump room, and the installation of the valve on the suction pipe.
In order to improve the reliability of the fire water pump water intake, to ensure that water can be supplied to the fire pipe network in time in the event of a fire. The fire water pump should adopt a vertical suction pipe, and the suction pipe should minimize turning.
5. Design of drainage in the pump room
Drainage facilities should be provided in the pump room, and it should be considered as far as possible to be able to directly drain to the outdoor drainage network by gravity. If the elevation of the basement pump room or outdoor drainage pipe network is lower than the elevation of the discharge pipe of the pump room, sewage lifting equipment should be installed. The commonly used drainage facilities in the pump house are drainage ditch and collection well, which are lifted by the submersible sewage pump and discharged to the outdoor drainage pipe network.
The drainage ditch in the pump room should be located in a place that is prone to overflow, dripping and splashing, and the drainage ditch should be laid with a water-passing grid. The selection of the submersible sewage pump in the collection well should be based on the larger of the overflow flow rate, the discharge flow rate and the other drainage volume discharged into the collection well. The submersible sewage pump should be set up for use, and the signal water level for the two pumps to start at the same time should be set to prevent the overflow flow from being much larger than the designed overflow flow when the water inlet valve of the pool is damaged, so as to avoid flooding the pump house.
The effective volume of the collection well should be calculated based on the 5min water output of the large submersible sewage pump, and the number of starts of the submersible pump per hour should not exceed 6 times.
6. Other issues
There are many problems that are easily overlooked in the design of common civil buildings or common industrial buildings, the living pump house and fire pump house, such as: the valve set on the water inlet pipe of the external network pool should adopt a lever type float valve or a hydraulic type water level control There should be no less than two automatic water level control valves such as valves; the living storage pool should be set up with a vertical structure; when the suction pipe of the water pump penetrates the pool wall, a flexible waterproof casing should be used.
In the design of building water supply and drainage, in addition to strictly following the current specifications, it should also pay attention to the problems encountered in actual projects or actual use, combined with the development trend of society, and fully consider the safety, reliability, practicality, reasonableness and economy of construction equipment. , Beautiful. We should constantly improve our own knowledge structure in actual projects, we should constantly pay attention to the new developments of our profession and all levels of society and their influence on design work, and constantly improve our own designs and design ideas, so that the designed projects are practical. There is also a sense of advancement.
