PP-R pipes, also known as type III polypropylene pipes, are made from random copolymerized polypropylene through extrusion and injection molding. They are a new type of plastic pipe product developed and marketed in Europe in the early 1990s. PP-R was developed in the late 1980s by using a gas-phase copolymerization process to randomly and evenly polymerize approximately 5% PE within the PP molecular chains (random copolymerization). This new generation of pipe material offers excellent impact resistance and long-term creep properties.
What is PP-R pipe?
PP-R pipes, also known as type III polypropylene pipes, are made from random copolymerized polypropylene through extrusion and injection molding. They are a new type of plastic pipe product developed and marketed in Europe in the early 1990s. PP-R was developed in the late 1980s by using a gas-phase copolymerization process to randomly and evenly polymerize approximately 5% PE within the PP molecular chains (random copolymerization). This new generation of pipe material offers excellent impact resistance and long-term creep properties.
What is the relationship between PP-R and PP-C?
International standards categorize polypropylene hot and cold water pipes into three types: PP-H, PP-B, and PP-R. There's no PP-C. The PP-C pipes available on the market are PP-B pipes, made from a special material specifically for block copolymerized polypropylene pipes. PP-B pipes are a relatively inexpensive type of hot and cold water pipe, but their heat and pressure resistance differ significantly from PP-R. For example, for service condition class 2, with a design pressure of 0.6 MPa/dn and a 25mm diameter pipe, a PP-R pipe with a wall thickness of 3.5mm would require a PP-B (PP-C) wall thickness of 5.1mm. For a design pressure of 0.8 MPa/dn and a 25mm diameter pipe, a PP-R pipe with a wall thickness of 4.2mm would be unusable because the required wall thickness is too thick. PP-C pipes, which have the same structural dimensions as PP-R pipes on the market, have much lower service conditions and should not be used interchangeably with PP-R pipes. Furthermore, PP-C pipes should not be substituted for PP-R pipes after determining the service conditions. Condition 2 means the design temperature is 70℃, and it is used for hot water.
What are the characteristics of PP-R pipes?
In addition to the advantages of conventional plastic pipes, such as light weight, corrosion resistance, anti-scaling, and long service life, PP-R pipes also offer the following key features:
1. Non-toxic and hygienic.
PP-R's raw material molecules contain only carbon and hydrogen, without any harmful or toxic elements. It is used not only for hot and cold water pipes but also for purified drinking water systems.
2. Thermal insulation and energy saving.
The thermal conductivity of PP-R pipes is 0.21 W/mK, only 1/200 that of steel pipes.
3. Excellent heat resistance.
The Vicat softening point of PP-R pipes is 131.5°C. Its maximum operating temperature can reach 95°C, meeting the requirements for hot water systems in building water supply and drainage regulations.
4. Long service life.
At an operating temperature of 70°C and a working pressure (P/N) of 1.0 MPa, PP-R pipes have a service life of over 50 years; at room temperature (20°C), they can reach over 100 years.
5. Easy installation.
PP-R has excellent welding properties. Pipes and fittings can be joined by hot-melt and electric-melt welding, making installation easy. The strength of the joints is greater than the strength of the pipe itself.
6. Recyclable Materials.
PP-R waste can be cleaned, crushed, and recycled into pipe and fitting production. The amount of recycled material used should not exceed 10% of the total volume, and this does not affect product quality.
What are the main uses of PP-R pipes?
1. Building hot and cold water systems, including central heating systems;
2. Building heating systems, including floor, wall, and radiant heating systems;
3. Drinkable purified water supply systems;
4. Central (central) air conditioning systems;
5. Industrial piping systems for transporting or discharging chemical media.
How can PP-R pipes be selected safely and economically?
1. Pay attention to determining the overall service factor (C) (i.e., safety factor) of the pipe: For general applications with long-term continuous operating temperatures below 70°C, select C = 1.25; for critical applications with long-term continuous operating temperatures ≥ 70°C and the possibility of prolonged operation at higher temperatures, select C = 1.5;
2. For cold water systems (≤ 40°C), select pipes and fittings with a P/N rating of 1.0 to 1.6 MPa; for hot water systems, select pipes and fittings with a P/N rating of ≥ 2.0 MPa.
3. After considering the above three principles, the SDR of the pipe fittings should not be greater than the SDR of the pipe; that is, the wall thickness of the pipe fittings should not be less than the wall thickness of the pipe of the same specification.
What precautions should be taken during the installation and construction of PP-R pipes?
1. PP-R pipes have lower hardness and rigidity than metal pipes. They should be protected during handling and construction to prevent mechanical damage from inappropriate external forces. Mark the pipe locations after concealed installation to prevent damage during secondary renovations.
2. PP-R pipes are somewhat brittle at temperatures below 5°C. Exercise caution during winter installation and use a sharp knife to cut slowly. Installed pipes should not be subjected to heavy pressure or impact. Cover areas susceptible to external forces with protective materials if necessary.
3. PP-R pipes are susceptible to degradation due to prolonged ultraviolet radiation. When installed outdoors or in direct sunlight, they must be covered with a dark protective layer.
4. Except for mechanical connections such as threaded inserts or flanges to metal pipes or water appliances, all other PP-R pipe connections should be made using hot-melt connections to ensure a seamless, leak-free pipe.
5. PP-R pipes have a high coefficient of linear expansion (0.15 mm/m°C). Technical measures must be taken to prevent expansion and deformation when laying pipes for exposed installation or non-direct burial concealed installation. 6. After installation, pipes must be pressure tested before sealing (for direct burial) or covering with a decorative layer (for concealed installation). The test pressure for cold water pipes is 1.5 times the system operating pressure, but not less than 10 MPa; the test pressure for hot water pipes is 2 times the operating pressure, but not less than 1.5 MPa. The pressure test time and method are specified in the technical regulations.
7. When laying PP-R pipes for exposed or concealed installation, supports and hangers must be installed as specified. PPR pipes combine ergonomic aesthetics with traditional Chinese aesthetics, are manufactured using top-quality international raw materials in a single molding process, and feature four unique reinforcement ribs for safety.
PPR Pipe Production Process
Ingredients → Automatic Loading → Heating and Extrusion → Vacuum Cooling → Secondary Water Cooling → Product Coding → Pipe Drawing → Cutting to Length → Product Inspection → Packaging and Arrangement → Warehousing
Features of PPR pipes
1. Non-toxic, rust-free, and scale-resistant, meeting the GB/T 17219-1998 drinking water standard;
2. Heat-resistant (water temperatures in pipes can reach up to 95°C) and pressure-resistant (pressure test strength can exceed 5 MPa);
3. Utilizing hot-melt connection technology, requiring no additional materials, the pipe and fittings are homogeneously melted into one piece, eliminating the risk of leaks;
4. Soft colors, attractive appearance, and surface-mountable;
5. Lightweight (only one-eighth the specific gravity of metal pipes), making installation, handling, and connection easy, saving labor costs;
6. Corrosion-resistant, preventing corrosion from ions in water and chemicals on the inside and outside of the pipes at the construction site;
7. Smooth inner wall, minimizing system pressure loss and facilitating rapid water flow;
8. Thermally insulating and energy-saving (the thermal conductivity is only one-two-hundredth that of metal pipes); generally, no insulation is required. 9. Its low tensile modulus and minimal expansion force due to temperature fluctuations make it suitable for direct burial in walls and floors.
10. Its long service life: 50 years when operated continuously at a pressure of 1.25 MPa and a temperature of 60°C.
PPR Pipe Welding Steps
1. Mark the insertion point for the pipe (equal to the insertion depth of the joint).
2. Ensure the surfaces of the pipe and joint are smooth, clean, and oil-free.
3. Heat the entire insertion depth, including the pipe and joint, in the welding tool.
4. The joint position can be adjusted within a few seconds after welding.
5. After the heating period is complete, push the pipe smoothly and evenly into the joint to form a secure and perfect bond.