what is pex pipe?

PEX pipe, also known as cross-linked polyethylene pipe, is made from polyethylene. The linear molecular structure of polyethylene is transformed into a three-dimensional network through physical and chemical methods, thereby improving its performance.

The main raw materials for PEX pipe are HDPE, along with additives such as initiators, cross-linkers, and catalysts. Other modifiers may also be added if required.

PEX pipe, also known as cross-linked polyethylene pipe, has the full English name: cross-linking polyethylene, abbreviated as CLPE, and is commonly referred to as PE-X. It is formed by polyethylene through a cross-linking reaction, which changes the polyethylene molecules from a two-dimensional structure to a three-dimensional network structure. The chemical and physical properties of the material are correspondingly enhanced, and the temperature and pressure resistance are improved.

When polyethylene changes from a linear structure to a network structure, its performance will undergo a complete and thorough change, and it will have outstanding wear resistance, explosion resistance, solvent resistance, dimensional stability, stress cracking resistance, weather resistance, radiation resistance and excellent electrical insulation. It has good low-temperature flexibility and excellent heat resistance. The softening point can reach 200°C and it can be used for a long time at 140°C. Its impact strength, tensile strength, creep resistance and rigidity are all better than HDPE.

After undergoing a cross-linking treatment, PEX pipes can withstand temperatures up to 95°C (95°C) for extended periods and 110°C (110°C) for short periods, making them ideal for hot water systems and floor heating.

Even at high temperatures, they maintain excellent mechanical strength and pressure resistance, resisting deformation or cracking.

PEX tubing is very flexible and comes in coils, making it easy to transport and handle.

During installation, it can be bent as needed (with a minimum bend radius of approximately eight times the pipe diameter), allowing it to bypass obstructions and reducing the number of joints, significantly reducing the risk of leaks. This makes it particularly suitable for complex piping layouts, such as those for underfloor heating installations.

It’s highly resistant to common chemicals like acids, alkalis, and salts, and won’t rust like metal pipes.

The exceptionally smooth interior reduces water flow resistance and is less prone to bacterial growth and scale buildup, ensuring long-term clean water flow.

It remains flexible in low-temperature environments. When water freezes inside the pipe, PEX pipes can accommodate the increase in ice volume by expanding (the expansion rate can be up to 9 times the pipe volume), and generally do not freeze and crack directly like rigid pipes (although repeated freezing and thawing should still be avoided).

Made of a soft, flexible material, PEX is more resistant to cracking caused by freezing than PVC pipe. Its flexibility also makes PEX easier to install. PEX piping can bend and curve around structural framing and other obstructions, reducing the need for holes and slots to accommodate the pipe. Bends in the pipe also eliminate the need for numerous elbow transition fittings, saving cost and installation time.

PEX piping can be used for:

Water supply lines or portable distribution systems

Radiant floor heating applications

Heat transfer applications such as floor cooling and snow and ice melting

Water distribution for hot water applications (including radiators)

Residential fire/sprinkler systems

PEX pipe, with its high-temperature resistance, corrosion resistance, flexibility, and ease of installation, has become the preferred piping material in modern construction and municipal engineering. Its differentiated cross-linking process (A/B/C) adapts to diverse applications, including heating, water supply, and industrial fluid flow. It significantly outperforms traditional metal pipes in terms of environmental friendliness and longevity.