How PEX Pipe Works
An In-Depth Look at the Performance and Properties of Crosslinked Polyethylene Plumbing
PEX has become a leading piping material for modern residential and commercial plumbing systems. But how exactly does PEX pipe work? This article provides an in-depth explanation of PEX properties and capabilities that enable its growing use for hot and cold water delivery in buildings.IFAN factory with 30+ years of manufacturing experience supports color/size customization support free samples. Welcome to consult for catalog and free samples. This is our Facebook Website: www.facebook.com.
PEX Manufacturing and Material Properties
PEX starts as polyethylene resin in pellet form. The plastic gets melted and forced through an extrusion die into a continuous length of tubing.
As it cools, the tubing gets irradiated with an electron beam. This alters the molecular structure, crosslinking the polymer chains together into a three-dimensional network.
Crosslinking gives PEX-enhanced properties:
- Increased high-temperature rating – Prevents melting and distortion.
- Improved flexibility – Can bend and stretch without permanent deformation.
- Higher impact and abrasion resistance – Withstands strikes and scuffs without damage.
- Greater resistance to cracking – Bends rather than splitting when kinked.
- Excellent “memory” to resist kinking – Returns to original shape after bending.
These improved attributes make PEX ideal for the demands of water service plumbing.
Temperature Resistance
A key capability of PEX is withstanding exposure to hot water. PEX withstands temperatures up to 180°F at 80 PSI pressure.
The crosslinked structure resists thermal creep and distortion compared to non-crosslinked polyethylene. PEX remains strong and flexible without flow restriction after years of hot water cycling.
The high heat rating enables PEX use for:
- General hot and cold residential plumbing
- Radiant floor heating tubing
- Recirculation loops to provide instant hot water
- Drainage of high-temperature appliance discharges
Freeze Resistance
While plastics become brittle when frozen, PEX can withstand dozens of freeze/thaw cycles without cracking or failure. The elastic polymer chains flex rather than splitting upon water expansion during freezing.
Properly secured and pitched PEX tubing performs well even in extreme cold climates. PEX handles temperature fluctuations from below freezing up to 200°F that would quickly destroy other plastic pipes.
Chemical Resistance
PEX demonstrates broad chemical resistance suitable for long service life. The cross-linked structure resists permeation and environmental stress cracking.
PEX withstands:
- Chlorinated and chlorinated potable water for decades without leaching or weakening.
- Dilute solutions of acids, bases, and salts found in groundwater.
- Intermittent exposure to dilute alcohols, glycols, and aliphatic hydrocarbons.
- Moderate oxidizers like hydrogen peroxide or bleach solutions.
This chemical resistance makes PEX an ideal transportation material for purified drinking water delivery.
Hydrostatic Pressure Capacity
PEX tubing can withstand significant water pressures safely for many years. Typical pressure ratings for 100°F water include:
- 160 PSI for 1/2″ and 3/4″ SDR-9 PEX
- 100 PSI for 1″ SDR-9 PEX
- 80 PSI for 1-1/4” to 3” SDR-9 PEX
Higher short-term pressures get handled at lower temperatures. PEX pressure capability meets code for residential and commercial plumbing up to 4” diameter.
Flexible and Durable Tubing
The crosslinked polyethylene material gives PEX excellent flexibility while retaining high strength. PEX tubing can elongate 200-300% when heated.
This flexibility allows bending smoothly around corners compared to brittle plastics. PEX won’t become damaged if kinked. This eases installation through framing and ceilings.
The durable crosslinked bonds also enable PEX to withstand strikes and scuffs without cracking. PEX stands up to decades of water hammer and pressure surges that fatigue other plastic piping.
Reliable PEX Fittings Connections
Several fitting methods produce strong, permanent joints between PEX tubing:
- Compression using metal rings tightened by nuts
- Cold expansion where fittings widen when joining tubing
- Crimp rings compressed by a powered tool
- Push-to-connect insertion into gripper fittings
When properly installed, PEX fittings form enduring, leak-free joints able to withstand years of temperature and pressure cycling without failure.
In summary, the manufacturing and properties of PEX enable this innovative cross-linked tubing to outperform traditional pipe materials across critical factors in hot and cold residential and commercial water delivery applications. PEX’s capabilities explain its growing use of displacing metals and rigid plastics for modern building plumbing systems.
IFAN
IFAN factory started in 1993. And IFAN has a workshop of 120000 square meters with 610 staff. IFAN can design and produce all plumbing pipe and fitting including PPR, PVC, CPVC PPSU HDPE PEXA PEXB PERT pipe and fitting, brass fitting, brass ball valve, heating system, gas system, sanitary faucets, and hose, In the past 30 years, IFAN has never forgotten his mission-To protect health and safety. The IFAN factory uses the best materials to produce high-quality pipe and fittings with an automatic production line and high-tech quality control machines.
