PVC Pipe Building Water Supply System

1. Pipeline pressure selection

1.1 The maximum allowable working pressure of the pipe should be selected and the rigidity of the pipe should be considered. When the nominal outer diameter dn≤40mm, the PVC pipe with a nominal pressure of not less than 1.6MPa should be selected; when the nominal outer diameter dn≥50mm, the pipe with a nominal pressure of not less than 1.0MPa should be selected.

1.2 The maximum working pressure of the pipeline at different operating temperatures should be corrected according to the pressure drop coefficient.

2. Pipeline layout

2.1 The hard polyvinyl chloride pipe for building water supply should be concealed. The main pipe and riser should be laid in the ceiling, pipe well, and pipe groove; the branch pipe should be laid in the leveling layer of the floor (ground), in the building decoration interlayer, or in the pipe groove excavated along the wall. The pipeline shall not be directly buried in the prestressed concrete structure layer. When the pipeline is laid in the pipe trench, its nominal outer diameter should not be greater than 25mm. When the length of the horizontal trench is greater than 1.5m, the consent of the structural professional designer should be obtained; when the pipeline is laid openly, effective anti-freezing measures should be taken in places where it may be hit. When the pipeline is laid outdoors, light-proof measures should be taken to avoid direct sunlight; when it is laid in cold areas, insulation and anti-freezing measures should be taken; when the pipeline is likely to condense, anti-condensation measures should be taken.

2.2 Branch pipes should be arranged near sanitary appliances or equipment with large water consumption.

2.3 The laying of water supply pipes should be convenient for maintenance and should not affect the special needs of the separate use functions of each building. Water supply pipes shall not pass through the transformer and distribution room. They shall not be laid in the flue, air duct, elevator shaft, elevator machine room, nor through the window or wall cabinet. They shall not pass through the toilet trough or urinal, and the vertical pipe shall not be <0.5m away from the end of the toilet trough.

2.4 Pipes should not pass through settlement joints, expansion joints, and deformation joints. When it is necessary to cross, a device to compensate for the expansion and shear deformation of the pipeline should be installed.

2.5 The pipeline should be at a sufficient distance from the heat source, and the temperature of the outer wall of the PVC pipe should not exceed 45℃ due to heat radiation. The net distance between the vertical pipe and the edge of the stove should not be less than 400mm, and the net distance from the heating pipe and the domestic gas water heater should not be less than 200mm.

2.6 The pipeline should not be arranged above the raw materials and products that may cause combustion, explosion or damage when in contact with water, and should avoid passing above the production equipment, and should not pass through the foundation of the production equipment.

2.7 When the pipeline is laid in parallel with other pipelines in the same trench, it should be arranged along the edge of the trench; when laid up and down, it should not be laid above the hot water or steam pipe or below the sewage pipe, and the plane position should be staggered; when crossing with other pipelines, protective measures should be taken.

2.8 When the pipeline passes through walls, slabs, beams, and columns, a steel casing should be added; when passing through the outer wall of the basement, a waterproof casing should be added; when passing through the floor slab and roof, waterproof measures should be taken.

2.9 PVC-U water supply pipes should not be used in the booster pump room of high-rise buildings; when the pipes connected to the pump room outlet pipes should use PVC-U water supply pipes, anti-water hammer and vibration reduction measures should be taken.

2.10 The horizontal pipe installation should have a slope of 2‰ to 5‰ towards the water discharge point.

Construction

1. General regulations

1.1 Pipeline on-site construction technicians should be trained before taking up their posts, and should understand the general properties of hard polyvinyl chloride materials for building water supply, master the key points of operation and safety measures, and should not blindly carry out construction.

1.2 When the temperature difference between the site where pipes and pipe fittings are stacked or stored and the construction site is large, the materials should be stacked on site for a certain period of time, and the installation and construction can only be carried out after the material temperature is close to the on-site conditions. Pipes and pipe fittings should not be contaminated by organic matter such as asphalt during stacking and transportation.

1.3 Fine-toothed saws, cutting knives or special tools should be used to cut pipes. The incision should be flat, smooth, and burr-free, and the cross section should be perpendicular to the center line.

1.4 When the pipeline is installed or the construction is interrupted, the open part of the pipeline should be sealed in time.

2. Installation of pipeline supports and hangers

2.1 The spacing of the pipeline supports should not exceed the requirements of the following table:

2.2 A fixed support should be installed on each layer of the riser. Fixed supports should be installed at the pipeline installation valve and other pipeline accessories, between two expansion joints, and at the pipeline branch pipe and water connection accessories.

2.3 Plastic finished pipe clamps can be used for the installation of pipelines with a nominal outer diameter of dn≤32mm; metal pipe brackets can be used for the installation of pipelines with a nominal outer diameter of dn≥40. When using metal pipe brackets, their tightening must not damage the pipe wall, and rubber pads or plastic soft pads should be added to the contact parts between the metal pipe clamps and the pipeline.

2.4 For pipelines with flexible connections sealed by elastic rubber rings, fixed brackets must be installed at the socket. Fixed brackets should also be installed at the location where the water flow of the main pipe changes direction.

2.5 See the figure below for the pipeline suspension method