Does Plastic Pipes have stable performance under high temperature and high pressure environment?

The performance stability of plastic pipes under high temperature and high pressure environments is an issue that requires special attention, especially in some specific application scenarios, such as hot water supply, steam pipelines, chemical transmission and other fields. Different types of plastic pipes have different high temperature and high pressure resistance capabilities, so it is very important to choose the right pipe. The following is a detailed analysis of the performance of plastic pipes under high temperature and high pressure environments:

High temperature resistance of plastic pipes
The stability of plastic pipes under high temperature environments depends on their materials and manufacturing processes. Most common plastic pipes (such as PVC, PE, PP, etc.) will experience varying degrees of performance degradation under high temperature conditions:
Polyvinyl chloride (PVC) pipes
PVC pipes generally have good low temperature performance, but their high temperature resistance is poor. Ordinary PVC-U pipes (rigid PVC pipes) tend to soften and lose rigidity in an environment above 60°C. Long-term exposure to high temperature environments will accelerate aging, and even deformation or breakage. Therefore, PVC pipes are generally not recommended for application scenarios with temperatures exceeding 60°C.
Polyethylene (PE) pipe
Ordinary PE pipes (such as PE80 and PE100 pipes) generally have a temperature resistance range of 40℃ to 60℃. At high temperatures, their molecular structure may soften, causing the pipe to deform or rupture. However, some PE pipes that have been specially treated or modified (such as PEX pipes, i.e. cross-linked polyethylene pipes) can withstand higher temperatures, up to 90℃-95℃, and even 100℃ under certain special conditions.
Polypropylene (PP) pipe
Polypropylene pipe (PP pipe) has good heat resistance, and its temperature resistance range can reach 90℃-95℃. In particular, PP-R pipe (random copolymer polypropylene pipe) can still maintain good strength and toughness when the water temperature is higher than 80℃, so it has been widely used in some hot water supply systems.
Chlorinated polyvinyl chloride (CPVC) pipe
CPVC pipe is a chlorinated PVC pipe, and its high temperature resistance is much better than that of ordinary PVC pipe. CPVC pipes can withstand temperatures ranging from 90℃ to 100℃, and can even withstand higher temperatures in some special applications, so they are used in hot water systems and industrial pipelines.
Cross-linked polyethylene (PEX) pipes

PEX pipes have excellent high temperature resistance, and their temperature resistance range is generally between 90℃ and 95℃. They are widely used in high-temperature water systems, floor heating systems, and some high-temperature hot water pipes. The cross-linking process enhances the stability and anti-aging ability of the pipe, so the performance is relatively stable at high temperatures.
High-pressure resistance of plastic pipes
In addition to high temperature resistance, the high-pressure resistance of plastic pipes is also very critical. The pressure bearing capacity of different plastic pipes is also different, depending on the thickness, material, production process and external environmental conditions of the pipe. Generally speaking, the pressure rating of plastic pipes is defined by standard tests. Common plastic pipe pressure ratings include PN4, PN6, PN8, PN10, etc., where PN represents the pressure rating (in bar, 1 bar is approximately equal to 1 atmosphere):
PVC pipes
PVC pipes have relatively poor pressure resistance and are usually used in low-pressure environments (such as water supply pipes, drainage pipes, etc.). The working pressure of PVC pipes is generally 6 bar to 10 bar, and it is easy to break or leak under high pressure. Therefore, PVC pipes are not suitable for high-pressure pipeline systems.
PE pipes
PE pipes have good pressure resistance, especially PE100 and PE80 pipes, which are usually used for medium and low pressure water supply and gas pipelines. The working pressure level of PE100 pipes can reach 16 bar or even higher. Therefore, PE pipes are widely used in high-pressure environments such as municipal water supply and natural gas transmission.
PP pipes
Polypropylene pipes perform well under high pressure environments, especially PP-R pipes (random copolymer polypropylene pipes), which are suitable for medium and high pressure water pipe systems. The pressure resistance of PP pipes can usually reach 8 bar to 12 bar. Its strong pressure resistance makes it widely used in water supply, HVAC, industrial transmission and other fields.
CPVC pipes
Compared with ordinary PVC pipes, CPVC pipes have stronger high pressure resistance and are usually used in medium to high pressure environments. The working pressure of CPVC pipes can reach 10 bar or even higher. It not only has good high temperature resistance, but also can withstand high pressure to a certain extent, so it is used in some industrial pipelines and hot water supply systems.
PEX pipes
Cross-linked polyethylene (PEX) pipes are widely used in hot water systems, floor heating systems and industrial pipelines due to their high temperature and high pressure resistance. The working pressure of PEX pipes can reach 8 to 10 bars, and they can still maintain high stability in some high-pressure environments. The cross-linking process increases its compressive and tensile resistance.

Choosing the right pipe material and ensuring that its working environment is within the range allowed by its performance is the key to ensuring the safe and long-term stable operation of the pipeline. If plastic pipes must be used in high temperature and high pressure environments, special materials that are resistant to high temperature and high pressure should be given priority, and relevant standards and installation specifications should be followed.