With the development of the pipe industry, PPR pipes have become particularly popular in the market. In addition to the advantages of conventional plastic pipes, such as light weight, corrosion resistance, anti-scaling, and long service life, PPR pipes are also non-toxic, hygienic, heat-insulating, energy-saving, long-lasting, and easy to install.
PPR Pipe Connection Methods
PPR pipes are primarily connected by hot-melt welding. Without proper hot-melt welding techniques, even with high-quality pipe materials, it can be difficult to ensure a quality installation. To ensure a quality connection, it is crucial to select the hot-melt tools that match the manufacturer's specifications. The heating time and temperature of the hot-melt welding machine must be strictly followed according to the operating procedures.
PP-R pipes are connected by hot-melt welding, and the connection between the pipe and fittings is only for one-time use. Therefore, when concealing water supply branches in walls, precise cutting must be performed according to design requirements and specific construction site conditions. If the pipes are buried, care should be taken to minimize joints in the buried section.
Before welding, carefully clean the pipe and fitting surfaces to remove oil, impurities, and burrs. Ensure the pipe is inserted into the fitting to the appropriate length. A uniform flange should form at the joint after connection. If it is uneven or even has a gap on one side, it indicates a suboptimal weld and a leak-proof joint. Reconnect the pipe promptly.
1. Pipes and fittings should be connected using hot melt. Direct threading of pipes and fittings is not permitted. Flanges can be used for connections to metal pipes, and fittings with metal inserts must be used for connections to water appliances.
2. Reliable hot melt equipment must be used for hot melt connections to ensure weld quality.
3. Use specialized scissors to cut the pipe vertically. The cut should be smooth and burr-free.
4. Clean the weld area of the pipe and fitting to avoid sand, dust, and other impurities that could damage the joint. Secure the heating head corresponding to the pipe size to the hot melt unit, connect the power cord, and wait for the heating head to reach the optimal temperature.
5. Mark the weld depth on the pipe with a pencil.
6. Insert the pipe and fitting into the hot melt unit and heat for the specified time.
7. After heating, remove the pipe and fitting and connect them immediately. If the pipe and fitting are misaligned during connection, minor adjustments may be made within a certain period, but the twisting angle must not exceed 5°.
8. After completing the connection, hold the pipe and fittings firmly with both hands and allow sufficient cooling time. Only release them once they have cooled sufficiently, and proceed to the next section.
After the pipes are connected, use colored paint on the wall or floor to indicate the pipe locations to prevent damage to the pipes during secondary renovations. Concealed water supply risers should have fixed support points where they pass through the floor slab to prevent accumulated expansion and contraction of the risers, which can cause displacement stress at the topmost branch pipe connection and damage the branch pipes. Furthermore, installing pipe supports following regulatory requirements is crucial for PP-R pipe installation.
PPR Pipe Construction and Installation Precautions
1. Construction personnel must receive technical training in the installation of Type III polypropylene pipes.
2. The pipes and fittings provided must comply with design specifications and be accompanied by product specifications and quality certificates.
3. Materials showing signs of damage must not be used. If any pipe quality abnormalities are found, a technical appraisal or re-inspection must be conducted before use.
4. Openings in the piping system during installation must be promptly sealed.
5. During construction and installation, the pressure ratings and intended use of hot and cold water pipes must be verified. Pipe markings should face outward and be located.
6. During pipe installation, axial distortion must be avoided, and forced corrections should not be applied when passing through walls or floors. When laying polypropylene water supply pipes parallel to other metal pipes, a protective distance of at least 100 mm should be maintained, and the polypropylene pipe should be placed on the inside of the metal pipe.
7. Indoor exposed pipe installation should be completed after the civil engineering finishes are completed. Before installation, holes should be properly reserved or sleeves should be embedded in coordination with the civil engineering.
8. When pipes pass through floor slabs, they must be installed with steel casing, 50mm above the ground level, and waterproofed. When pipes pass through roofs, strict waterproofing measures must be implemented. Fixed supports should be installed at the front of the crossing.
9. Pipe laying below the indoor floor level should be carried out after the backfill soil has been compacted and re-excavated. Pipe laying before backfill or in uncompacted soil is strictly prohibited.
10. The trench bottom for laying pipes must be flat and free of protruding hard objects.
11. When backfilling buried pipes, the backfill soil around the pipe must not contain any hard objects that could come into direct contact with the pipe wall.
12. Where pipes exit the floor level, a protective pipe should be installed, 100mm above the floor level.
13. When pipes pass through foundation walls, a metal casing should be installed. The clearance between the casing and the reserved hole in the foundation wall should be at least 100mm, unless otherwise specified in the design.
14. When the pipeline passes through neighborhood roads and the covering soil thickness is less than 70mm, strict protection measures should be adopted.
PPR Pipe Pressure Testing Methods
1. A water pressure test must be performed before completing pipe installation to confirm the weld condition and eliminate potential hazards.
2. The water pressure test should be performed 24 hours after the hot-melt connection. Before the test, the pipes must be secured and the joints must be exposed.
3. The test pressure for cold water pipes should be 1.5 times the piping system's working pressure, but not less than 1.0 MPa; the test pressure for hot water pipes should be 2.0 times the system's working pressure, but not less than 1.5 MPa.
4. During the pressure test, the water meter should be turned off to prevent damage. Use a manual pressure test pump or an electric pump to slowly increase the pressure. The test should last for at least the specified time.