The difference between PPR and PP

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The difference between PPR and PP: PP-R is better; the main drawback of PP pipes is their poor low-temperature resistance – they are difficult to use at temperatures below 5 degrees. PP-R is a maintenance-free type of pipe, but there is one issue: pipes produced by ordinary manufacturers are of inferior quality; a wall thickness of over 2 MM is required, while most such pipes have a thickness of less than 2 MM. PPR pipes are officially known as random copolymer polypropylene pipes, and they are currently the most commonly used type of water supply pipe in home renovation projects. 　　The joints of PPR pipes are created using heat fusion technology, which ensures that the pipes are fully integrated with each other. As a result, once the installation is complete and the pressure test is passed, there will be no more leaks, offering extremely high reliability. But this doesn’t mean that PPR pipes are defect-free; their heat resistance and pressure resistance are slightly lower, and the maximum operating temperature should not exceed 70 degrees℃ ； Each section has a limited length, and it cannot be laid in a curved manner; if the pipeline needs to be laid over long distances or through many corners, a large number of joints will be required during installation ； Pipes are cheap, but the prices of accessories are relatively high. In terms of overall performance, PPR pipes are currently the most cost-effective type of pipe, which is why they are the preferred material for home plumbing renovations. 　　The PPR pipes available on the market come in two main colors: white and gray. The reason for this difference, according to distributors, is due to variations in the PPR particles used as raw materials. 　　In general, during water and electricity renovation, the existing water pipes are replaced. When recommending PPR pipes to homeowners, decoration companies and suppliers always choose hot water pipes, even for areas where cold water flows. They claim that since the technical specifications of hot water pipes are higher than those of cold water pipes, and the price difference is not significant, hot water pipes are used for all water pipeline renovations. Another fact is that even if you want to buy cold water pipes, it’s difficult to find them on the market, as they are only available for industrial use and not for home use. 　　The diameter of PPR pipes can range from 16mm to 160mm. In home applications, the most commonly used diameters are 20mm and 25mm (commonly referred to as 4-inch pipes and 6-inch pipes respectively), with 4-inch pipes being more frequently used. 　　I. What is a PP-R pipe? A PP-R pipe, also known as type III polypropylene pipe, is made by extruding random copolymerized polypropylene to form pipes, and by injection molding to create fittings. It is a new type of plastic piping product developed and applied in Europe in the early 1990s. PP-R is a new generation of piping material that emerged in the late 1980s, created through a gas-phase copolymerization process in which about 5% of PE is randomly and uniformly polymerized within the PP molecular chains (random copolymerization). It possesses good impact resistance and long-term creep resistance. 　　II. What is the relationship between PP-R and PP-C? In the past, PP-C pipes and fittings appeared on the domestic market, and their installation method was the same as that of PP-R pipes. Many people are confused about the differences between PP-R and PP-C, which has led to numerous misunderstandings and confusion. According to international standards, polypropylene hot and cold water pipes are classified into PP-H, PP-B, and PP-R types; there is no PP-C type. The PP-C pipes available on the market are actually PP-B pipes, whose raw material is a special material designed for block copolymerized polypropylene pipes. PP-B pipes are a type of hot and cold water pipe; they are relatively inexpensive, but their heat resistance and pressure resistance are significantly inferior to those of PP-R pipes. For example: Using condition classification 2, with a design pressure of 0.6 MPa; for dn25 pipes, the wall thickness of PP-R pipes is 3.5 mm, while that of PP-B (PP-C) pipes is 5.1 mm ； The design pressure is 0.8 MPa at a diameter of 25 mm; the wall thickness of PP-R pipes is 4.2 mm, while PP-B (PP-C) cannot be used for this purpose. Because the required wall thickness is too thick. PP-C pipes available on the market that have the same structural dimensions as PP-R pipes are designed for much lower operating conditions; they cannot be used interchangeably with PP-R pipes, and PP-C pipes cannot replace PP-R pipes once the appropriate operating conditions have been determined. Condition 2 indicates a design temperature of 70°C for hot water supply. 　　III. What are the characteristics of PP-R pipes? In addition to the common advantages of plastic pipes such as light weight, corrosion resistance, no scaling, and long service life, PP-R pipes also have the following key features: 1. Non-toxic and hygienic. The raw material molecules of PP-R consist only of carbon and hydrogen; there are no harmful or toxic elements present, making it hygienic. It can be used not only for hot and cold water pipelines but also in systems for pure drinking water. 　　2. Heat preservation and energy saving. The thermal conductivity of PP-R pipes is 0.21 W/m·K, which is only 1/200 that of steel pipes. 　　3. Good heat resistance. The Vicat softening point of PP-R pipes is 131.5°C. The maximum operating temperature can reach 95°C, meeting the requirements for hot water systems as specified in building plumbing codes. 　　4. Long service life. Under operating temperatures of 70°C and an operating pressure (P.N) of 1.0 MPa, PP-R pipes can have a service life of over 50 years ； At room temperature (20°C), its service life can exceed 100 years. 　　5. Easy to install, with reliable connections. PP-R has good welding properties; pipes and fittings can be connected by heat fusion or electrofusion. It is easy to install, and the joints are reliable, with the strength of the connection areas being greater than that of the pipes themselves. 　　6. Materials can be recycled. PP-R waste is cleaned and crushed before being recycled for the production of pipes and fittings. The amount of recycled material used should not exceed 10% of the total amount, as this does not affect product quality. 　　IV. What are the main uses of PP-R pipes? 1. Hot and cold water systems in buildings, including central heating systems ； 　　2. Heating systems in buildings, including floor, wall panel, and radiant heating systems ； 　　3. Purified water supply system for direct drinking ； 　　4. Central (centralized) air conditioning system ； 　　5. Industrial pipeline systems for transporting or discharging chemical media, etc. 　　V. What are the differences between PP-R pipes and several types of plastic hot and cold water pipes? See the table for details.
VI. How to choose PP-R pipes in a way that is both safe and economical?
1. Pay attention to determining the overall utilization factor C (i.e., the safety factor) of the pipes: In general situations, where the temperature remains below 70°C on a continuous basis, a value of C=1.25 can be used ； For important applications where continuous use at temperatures of ≥70°C is required, and where operation at even higher temperatures for extended periods is possible, C=1.5 can be selected ； 　　2. For cold water (≤40°C) systems, use piping and fittings with a pressure rating of P.N1.0～1.6MPa ； 　　For hot water systems, pipes and fittings with ≥PN2.0MPa should be used. 　　3. After considering the above three principles, the SDR of the fittings should not be greater than that of the pipe; in other words, the wall thickness of the fittings should not be less than that of pipes of the same specification. 　　VII. What issues should be considered during the installation of PP-R pipes? 1. PP-R pipes are less hard and have poorer rigidity compared to metal pipes; therefore, they need to be protected during handling and installation to avoid mechanical damage caused by excessive external forces. After concealed installation, the location of the pipes should be marked to prevent damage to them during subsequent renovations. 　　2. PP-R pipes exhibit a certain degree of low-temperature brittleness at temperatures below 5°C; care should be taken when working in winter, and sharp tools should be used to cut the pipes slowly. The installed pipes must not be pressed or struck; if necessary, protective covers should be placed over areas that are susceptible to external forces. 　　3. PP-R pipes are prone to aging and degradation when exposed to ultraviolet light for extended periods; they must be covered with a dark protective layer when installed outdoors or in areas exposed to direct sunlight. 　　4. Except when connecting PP-R pipes to metal pipes or water fixtures using mechanical connection methods such as threaded inserts or flanges, heat fusion welding should be employed for all other connections in order to integrate the pipes together and eliminate any leakage points. 　　5. PP-R pipes have a relatively high linear expansion coefficient (0.15 mm/m°C); therefore, technical measures must be taken to prevent the pipes from expanding and deforming when they are installed in exposed locations or not buried directly underground. 　　6. After pipeline installation, pressure testing must be carried out before sealing the pipeline (for direct burial) or applying a decorative layer (for non-direct burial). The pressure used for testing cold water pipes is 1.5 times the system’s operating pressure, but it must not be less than 1 MPa ； The test pressure for hot water pipes shall be twice the operating pressure, but shall not be less than 1.5 MPa. The pressure testing time and methods are specified in the technical regulations. 　　7. When PP-R pipes are installed in exposed fashion or buried non-directly, supports and hangers must be installed in accordance with the regulations. 　　Production standard: GB/T18742-2002 – Quality identification of PPR pipes. Genuine PPR pipes should comply with the standard GB/T18742-2002, and pipe fittings should also meet this standard ； The performance of pseudo-PP-R pipes and fittings cannot meet the aforementioned standards. It should be noted that the service life of fake PP-R pipes is only 1–5 years, whereas the service life of genuine PP-R pipes is over 50 years. 　　PPR Pipes – How to Choose Them PPR pipes are widely used in industrial and residential buildings for domestic water supply, potable water supply, and hot water heating. PPR pipes are divided into two types: hot water pipes and cold water pipes. Cold water pipes have thin walls, while hot water pipes have thick walls; therefore, hot water pipes perform much better in terms of resistance to fracture. Additionally, hot water pipes are more expensive than cold water pipes. To be on the safe side, many manufacturers do not distinguish between hot and cold water pipes during installation, in order to increase the safety factor. 　　1. High-quality, flexible PPR pipes and fittings are not prone to deformation under pressure; even if deformed, they do not break, and this **reduces the need for connectors. 　　2. Corrosion-resistant and water-proof: PPR pipes and fittings have chemical properties that enable them to resist erosion by chemical elements in water; their smooth inner surfaces also prevent the formation of deposits.
3. Heat and pressure resistant: PPR pipes and fittings can withstand a water pressure of 45 kilograms per square centimeter at normal temperatures, with the pipe remaining unchanged up to a temperature of 112 degrees Celsius.
4. Long service life: PPR pipes and fittings have strong resistance to aging, allowing them to serve for over 50 years under normal conditions. 　　5. Easy and fast installation: The flexibility of PPR pipes and fittings makes installation very quick, and they are easy to connect (using a heat fusion machine for socketing connection), ensuring safety and reliability. 　　6. Cost-effective: Due to its simple construction, it avoids conflicts and interference with other projects, reduces the construction time, and its installation costs are 60% lower than those of copper pipes, offering excellent economic advantages. 　　Therefore, consumers should be cautious when making their purchases; they must choose pipes that are suitable, produced by reputable manufacturers, and come with a quality guarantee. Additionally, there are some things to keep in mind during installation, so it’s a good idea to listen to the advice of experts. 　　Experts recommend: Have professionally trained technicians carry out the operation. At the same time, the process flow is also very important. Following the principle of horizontal and vertical alignment, deep grooves larger than the diameter of the water pipes should be cut into the floor of the room’s foundation, after which PPR pipes are laid and then thermally fused together one by one in sequence. After all PPR connections are fused together using heat melting technology, a pressure test lasting more than 24 hours must be carried out; if the site conditions permit, this testing period can be extended. Fill it in only after ensuring that there is no seepage or leakage.