2.1 general provisions
2.1.1 the selection of ABS plastic steel pipes for building water supply shall be determined according to the continuous working water temperature and working pressure. Pipes with working pressure of 1.0MPa can be selected for low-rise buildings, and pipes with working pressure of 1.6Mpa should be selected for high-rise buildings.
2.1.2 ABS plastic steel pipes can generally be exposed and concealed. Concealed laying methods include direct burial and non direct burial. Directly buried form: Non directly buried form: —— Embedded wall laying —— Pipeline well, in ceiling and behind decorative plate —— Laying in floor surface layer ——
2.1.3 technical measures for pipeline temperature deformation shall be taken into account when the pipeline is laid in the overhead layer of the floor; In case of direct burial and concealed laying, it shall coordinate with the construction and structure discipline and take corresponding protective measures.
2.2 pipeline layout and laying. 2.2.1 the main water supply pipe set in public places should be laid in the pipeline well.
2.2.2 the exposed water supply pipe should be arranged near the corner, wall or column of the sanitary ware with large water consumption.
2.2.3 the exposed water supply pipe shall not pass through the bedroom, storage room, flue and air duct. The water supply pipeline shall be far away from the heat source, and the clear distance from the main pipe to the water heater or stove edge shall not be less than 400mm. When the conditions are not met, thermal insulation protection measures shall be taken. However, the minimum clear distance shall not be less than 200mm.
2.2.4 supports and hangers shall be set for exposed and non directly buried pipelines. For pipeline laying, angle free arms, expansion joints or various compensators shall be used to compensate for pipeline deformation. When they cannot be used, pipeline supports and hangers shall be fixed supports. The spacing between fixed support and sliding support shall be determined according to table
2.5.3. 2.2.5 for pipes directly laid on the wall or floor surface, longitudinal expansion compensation may not be considered. For pipes directly laid on the wall, the outer diameter shall not exceed 25mm.
2.2.6 metal waterproof flexible casing shall be set at the place where the pipeline passes through the outer wall of the basement, and effective waterproof measures shall be taken at the place where the pipeline passes through the roof. Reinforcement measures shall be taken at the connection between exposed pipeline and water hydrant.
2.2.7 when the water supply pipeline is laid in parallel with other pipelines in the same trench (frame), it should be arranged along the edge of the trench (frame). When laying up and down in parallel, it should not be laid on the top of hot water or steam pipes, and the plane position should be staggered. When laying cross with other pipelines, protective measures or metal casing should be taken.
2.2.8 ABS plastic steel pipe shall not be directly used for contacting the heat source pipe. The ABS inlet and outlet pipe connected with the hot water appliance shall have a metal transition pipe more than 400 mm away from the hot water appliance .
3 Calculation of pipe deformation
2.3.1 the axial deformation of free pipe caused by temperature difference can be determined according to the following formula:
△L=△TxLxa (1) △T=0.65△ ts+0.10△ tg (2) △ l pipeline expansion length (mm) △ t calculated temperature difference (℃) △ TS maximum temperature change of fluid in pipeline (℃) △ TG maximum temperature change of air outside the pipeline (℃) L length of free pipe section (m) Linear expansion coefficient (mm / m · 0C) a = 0.101 2.3.2 the pipe system shall make full use of pipe turning and compensate with cantilever end.
The minimum free arm length is determined as follows: Where: LZ minimum length of free arm △ l the expansion length of the pipeline from the fixed fulcrum (mm), and the de nominal outer diameter (mm) can be calculated and determined according to formula (1) in this regulation; K material proportion coefficient, ABS resin is 332.4 pipeline hydraulic calculation
2.4.1 the hydraulic loss along the water supply pipeline can be calculated according to the following formula, and the local head loss is calculated as 25% of the head loss along the pipeline. Hf = λ LV2/2djg (3) Where HF: head loss along the pipeline (m); λ : Hydraulic friction coefficient; L: pipe length (m); DJ: calculated inner diameter of pipeline (m); V: average water flow velocity in the pipeline (M / s); G: gravitational acceleration, 9.81 (kg. M / S2). 1502.5 design of pipe clamp and pipe support spacing
2.5.1 the basic principle of correct pipe clamp and pipe support is to allow the pipe to move freely axially, and provide lateral suppression and appropriate support for the pipe.
2.5.2 selection requirements of pipe clamp and pipe support: a allow the pipe to move freely axially; B avoid sharp burrs or edges to avoid cutting or damaging the pipe wall. C provide appropriate lateral stress. D do not restrict the axial movement of the pipe.
2.5.3 maximum support spacing of ABS plastic pipe (maximum spacing of pipe clamp and pipe support)