Analysis of the hot technical issues of the impact of the 2019 edition of "building water supply and drainage design standards" on real estate projects
The standard for design of building water supply and drainage (GB 50015-2019) has been officially implemented in March 2020. At 10 am on June 13, Liu Wei, chief engineer of Tianyou water supply and drainage major, explained the impact of the new regulation on real estate projects in tenio online classroom.One hour live broadcast, more than 4000 people watched onlineWith many colleagues in the industry, enthusiastic interaction, hot spot issues continue to emerge.How to master the water supply pressure and zoning?How to set up drainage and ventilation pipes?How to control rainwater in sponge city design?The chief engineer of Tianyou said that the high-frequency hot technical issues of live broadcasting were selected and shared with real estate customers and peers in the industry.
TENIO Tianyou, chief engineer
Water pressure of sanitary ware
The working pressure of washing basin, shower, washing machine and other sanitary appliances is increased to 0.10 MPa, and the flushing water tank of toilet is increased to 0.05 MPa (0.05 MPa and 0.02 MPa respectively in the 09 edition specification), which brings about changes in water supply mode or water supply division.
● The impact of this：The water supply division is more sensitive to the requirements of municipal water pressure, especially for buildings whose floor height is close to the critical height of the pump house, the relatively accurate water pressure of the project location shall be confirmed with the water supply department in the scheme stage, and the economy, reliability and rationality of the water supply system shall be comprehensively considered, so as to fully utilize the municipal water pressure and avoid the water pressure on the top floor caused by the actual water pressure not conforming to the designLack of strength and so on.
✦ Related hot issues
Is it possible to increase the municipal pressure to avoid setting up pump rooms in small public buildings such as distribution buildings or kindergartens?
As a key external design parameter, municipal water supply pressure shall be submitted to the designer after communication and confirmation between the owner and the water supply department.
How to determine the municipal water supply floor?
Combined with municipal water supply pressure, floor height, pipe network along the way and local head loss, valve and instrument head loss, terminal water pressure calculation and determination.
How to set the partition when the water pressure of sanitary ware is increased?
Combined with the provisions of article 3.4.3, 3.4.4 and 3.4.5 of the water construction standard, the water supply and pressure reduction modes such as parallel water supply of water pump group, partition of bottom pressure reducing valve and branch pipe pressure reducing valve can be combined to meet the requirements that the hydrostatic pressure at the bottom of each partition is not greater than 0.45MPa, that of residential household pipe is not greater than 0.35Mpa, and that of end appliance is not more than 0.20mpa.
Drainage pipes shall not pass through the storage room
●This is a new clause in the 19th edition of the standard.
Food or valuables may be stored in the storage room at the later stage, and the leakage of drainage pipes may easily cause health risks or property losses, which may lead to disputes, claims and even personal injury.Coordination of the layout of storage room and drainage pipeline also results in the limitation of room function division. When the storage room is really needed in the position with drainage pipeline, pipeline isolation measures can be added (pipeline interlayer is set at the top of storage room, pipeline well is set for drainage riser, etc.).
✦ Related hot issues
Does the storage room refer to the in house storage room of the residence, but does not include the underground storage room?
The code does not indicate that it is only the storage room in the housing. Combined with the revision principle of the specification and the publicity and implementation of the specification, it should include all rooms with storage function that may store valuable and food, including but not limited to: "storage room", "storage room", "storage room", etc., which is also in line with the design of "drainage pipes shall not be laid in food and valuable commodity warehouse" in new standard 4.4.3-3The principles are consistent.When it is confirmed that the room function does not store the above items, the actual function of the room can be defined, such as "utility room", "tool room", etc.
Can pipes other than drainage pipes pass through the storage room?
It should be considered in combination with the types of storage items, the maintenance and management of pipelines and the ownership of the room, and the principle of safety, hygiene, easy maintenance and management should be taken into consideration.
The drainage pipe shall not pass over the main and non-staple food operation, cooking and preparation in the canteen kitchen and catering industry kitchen
When the horizontal drainage pipe is set above the kitchen, it may leak or be affected by hot and humid air, and the outer wall may be dewed or dripping, which will cause the safety and health accidents of contaminated food.Compared with the 09 edition of the specification,The new bid cancels the additional clause of the original clause: "when it is unavoidable due to the restriction of conditions, protective measures shall be taken."。
✦ Related hot issues
Can drainage risers be installed in the kitchen area of public catering?
This clause is only limited to "above the main and non-staple food operation, cooking and preparation". The drainage riser crossing the kitchen operation area does not violate this clause. From the perspective of hygiene, it is recommended to take encapsulation measures.The main and non-staple food storehouses in the kitchen area belong to "food warehouses" and should not be equipped with drainage pipes.
Drainage capacity of riser and installation of vent pipe
Due to the change of the test method of the drainage riser and the adjustment of the new standard terms, the application scope of the common extended roof ventilation riser is greatly relaxed for high-rise residential projects. The following table shows the comparison of drainage flow of DN 100 riser in high-rise residential buildings with different sanitary appliances(single toilet: toilet with single pipe; double toilet: shared riser for double toilet)：
The clauses related to the drainage capacity of the drainage riser and the installation of the vent pipe are the controversial parts since the new standard was issued.Different regions and different families have great differences in water use, and the internal state of the pipeline varies greatly after a certain period of time. In addition, the adjustment of sanitary ware configuration and even the demolition and modification of the vertical pipe increase the uncertainty of drainage.In order to improve the later use quality of the project, it is suggested that a certain safety margin should be considered in the design, and the sanitary ware with the same function should be calculated according to the larger displacement.
✦ Related hot issues
Are ventilation pipes provided in toilets above 10 floors?
There is no clear requirement in the code, which can be comprehensively considered according to the design drainage flow, the number of horizontal pipe sanitary ware, the length of horizontal branch pipe, the maximum drainage capacity of riser, construction and decoration standards and other factors.
Is the new standard applicable to special single riser drainage system?
Due to the wide variety of special single riser system and great difference in drainage capacity, the new standard cancels the relevant data of special single riser drainage system. When it is necessary to adopt, the system setting can refer to the relevant association standards, and the designed drainage capacity of the system shall be defined. The water carrying capacity of the product shall also be determined through the test conducted by an institution with test qualification approved by the government administration department (instantaneous flow method).
Is the new standard standpipe drainage capacity suitable for internal spiral drain pipe?
The standard drainage capacity data are measured. When the internal spiral drainage pipe is used, the system setting can refer to the relevant association standards, and the designed drainage capacity of the system shall be defined. The water carrying capacity of the product shall also be determined through the test conducted by an institution with test qualification approved by the government administrative department.Because the testing methods adopted by the association standard and the 19th edition standard are not unified, it is suggested to adopt the constant flow method and the instantaneous flow method respectively, and both of them should be satisfied.
Separate drainage of bottom layer
The new standard has the following requirements: no ventilation pipe at the bottom layer and separate drainageThe drainage pipes of residential buildings are discharged by households; the public built toilet is discharged separately and the number of appliances meets the requirements;The length of horizontal drainage pipe shall not be greater than 12m.
✦ Hot issues
Is this clause applicable to bottom drainage pipes with overhead floors?
It is not only the first floor, but also the lowest floor with overhead drainage system.
The length of horizontal drainage pipe should not be greater than 12m. Does it include drainage pipe (from inside the building to outdoor inspection well)?
When the horizontal drainage pipe directly leaves the house, the indoor horizontal drainage pipe and the discharge pipe are continuous, and the water flow state is also continuous. It is not reasonable to distinguish the horizontal drainage pipe and the discharge pipe with the outer wall as the boundary. It is suggested that the length of the horizontal drainage pipe should be from the drainage gas end to the inspection well (schematic diagram 1 of single row at the bottom).
Schematic diagram of single row at bottom 1
When the horizontal drainage pipe is set with vertical transition pipe section when it is out of the external wall, it can be calculated from the beginning of drainage to the pipe transition point (schematic diagram 2 of single row on the bottom floor).
Schematic diagram of bottom single row 2
Rainwater in residential area
The rainwater outfall should be set at the end of rainwater control and utilization facilities, and be discharged in the form of overflow.For areas with sponge city or rainwater control requirements, rainwater should not be directly discharged into municipal pipe network.Combined with the design scheme of sponge City, the rainwater runoff on the surface and roof of the site is planned,joinAnd guide roof androadrain,adoptIn the way of disconnection, it enters into the ecological facilities such as concave green space or is collected to the storage tank, and the overweight current rainwater is discharged to the municipal pipe network in the form of overflow.
Roof rainwater disconnection
Road rainwater disconnectionAnd overflow inlet
▲End overflow discharge
✦ Related hot issues
Can the concave green space be higher than the road surface?
According to the sponge facilities set in the site, rainwater control and utilization mode.When the concave green space is used as the roof rainwater regulation and storage facilities, and the rainwater pipe network end is equipped with a storage tank, the road rainwater can overflow and discharge through the storage tank.According to this rainwater control scheme design, the concave green space can not consider the road surface rainwater, the vertical relationship between the road surface and green space, but there should be measures to ensure that the green space rainwater does not flow to the road surface.
In recent years, the research, development and design concept of domestic and foreign water supply and drainage technology are reflected in the new standard. No matter how the specification is adjusted, the bottom line of safety and health will remain unchanged.Limited to space, this paper only analyzes some provisions related to water supply, drainage, rainwater and other hot issues related to real estate projects. We welcome your colleagues to exchange and discuss.
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