Technical code for building drainage hard polyvinyl chloride pipeline engineering

3.1.20 The location of the expansion joint should be close to the water confluence pipe fittings (Figure 3.1.20), and should meet the following requirements:
1 When the riser passes through the floor with a fixed support and the drainage branch pipe is connected under the floor slab, the expansion joint should be set under the 　　 of the water converging pipe (Figure 3.1.20 (a), (c)).　　　　2 When the riser passes through the floor and is fixedly supported and the drainage branch pipe is connected above the floor slab, the expansion joint should be set on the 　　 of the water converging pipe (Figure 3.1.20 (b)).　　　　3 When the riser pipe crosses the floor without a fixed support, the expansion joint should be set above or below the water converging pipe (Figure 3.1. 　 20 (e), (f)).　　　　4 When there is no drainage pipe connected to the riser, the expansion joints can be placed at any part of the floor according to the design spacing of the expansion joints ((　　 d), (g) in Figure 3.1.20).　　　　5 The expansion joint on the horizontal pipe shall be located at the upstream end of the water flow confluence pipe.　　　　6 When the riser passes through the floor for a fixed support, the expansion joint shall not be fixed; when the expansion joint is fixedly supported, the riser shall not be fixed when it passes through the floor.　　　　7 Expansion joint socket should follow the direction of water flow.　　　　 8 Pipes buried in the ground or buried in walls or concrete columns shall not be provided with expansion joints.　　 3.1.2l The cleaning or inspection opening should meet the following requirements: 　　　　1 The riser should be set at the ground floor and when turning on the floor, the inspection opening should be set, and the center of the inspection opening should be lm from the ground. In areas where the average temperature of the coldest month is 　　 below -13°C, the riser should be set up at the highest level 0.5m away from the indoor ceiling.　　　　2 The riser should be provided with an inspection port every six floors.　　　　3 An inspection port or a cleaning port should be provided on the cross-main pipe where the water flow angle is less than 135 degrees.　　　　4 In public buildings, it is advisable to install cleaning ports on the sewage horizontal pipes connecting 4 or more urinals.　　　　5 When the straight line distance between the horizontal pipe and the discharge pipe is greater than the specified value in Table 3.1.2l, an inspection port or a cleaning port shall be provided.　　 　　 The maximum distance between the inspection opening or cleaning opening of the horizontal pipe on the straight pipe section
3.1.22 When the drainage pipe is arranged in a basement, semi-basement or outdoor overhead arrangement, the bottom of the riser should be provided with buttresses or fixed measures should be taken. 3.2 Pipeline hydraulic calculation 3.2.1 The drainage flow, equivalent, and outer diameter of the drainage pipe of sanitary ware should be determined in accordance with the national standard “Code for Design of Water Supply and Drainage for Buildings” (GBJ15), but the drainage of the stool and sink The flow, equivalent, and outer diameter of the drain pipe should be determined in accordance with Table 3.2.1.　　　　 Stool and wash basin drainage flow, equivalent, drainage pipe diameter
3.2.2 The design flow rate per second of domestic drainage shall be calculated and determined in accordance with the national standard <<Code for Design of Building Water Supply and Drainage>> (GBJ15).　　 3.2.3 The maximum drainage capacity of the drainage standpipe shall be determined in accordance with Table 3.2.3.
Note: This table refers to the drainage capacity when the discharge pipe and the horizontal pipe are one diameter larger than the riser pipe connected to it. 3.2.4 Hydraulic Calculation horizontal drainage pipes should meet the following requirements: 1 calculated according to the formula: where: V – velocity (m / s); n – roughness coefficient, should adopt 0.009; R – Hydraulic Radius (m); 　　　　　　　　　I – pipe slope.　　　　2 can be determined according to the horizontal pipe hydraulic calculation diagram in Appendix A of this Regulation.　　 3.2.5 The minimum slope and maximum calculated fullness of the horizontal pipe shall be determined in accordance with Table 3.2.5.　　　　 Horizontal pipe minimum slope and maximum calculated fullness