Difference Between Classes of PEX Piping

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Understand Differences Between Classes Of PEX Piping And Systems

Installing pipes requires being updated with the latest development and changes in the industry to prevent future problems. One of the changes that have taken place in the plumbing world is the successful poly B replacement and discontinuation in the use of copper pipes. Classes of PEX piping is the accepted piping for installation because of its resistance to corrosion and high flexibility features.

The two types of plastic types include the PEX (Cross-linked Polyethylene) and PB (Polybutylene or Poly B™). Meanwhile, these pipes are different in certain ways. Poly B™, for instance, is made of a plastic resin and it is commonly used for plumbing pipes because of its cost-effectiveness, flexibility, resistance to freezing, etc. However, people have stopped the use of poly B due to its delicate features and the issues it causes. Know the Facts on Poly B™ Piping.

Read: What is Poly B™ Piping?

The Difference between Classes of PEX Piping and Others

PEX is considered to be highly reliable because it is made from High-Density Polyethylene (HDPE). For several uses all over the world, PEX has been used for poly B replacement. It is the preferred plumbing solution for domestic purposes.

The main difference between Poly B™ (PB) and PEX is their manufacturing. During the production of PEX, there is a connection between the polymer chains to one another, and this is called “Cross-Linking,” but it does not happen in Poly B™ pipes.

Because of the Cross-Linking of polymer chains, PEX is considered to be more favorable and the perfect poly B replacement option. The most significant benefit of PEX over Poly B™ is its pressure tolerance. Irrespective of the efforts of manufacturers to enhance the quality of PB, PEX continues to have a higher tolerance to pressure than Poly B™.

Furthermore, chlorine that is popularly used to purify water subtly causes the Poly B™ pipes’ bonds to rupture and leak. Over time, Poly B™ can become weakened and break due to water pressure. Meanwhile, PEX can withstand water pressure more than PB regardless of the amount of chlorine.

Read: Color Coding Water Lines

Classes of PEX Piping – REHAU Class is the Superior Piping

People ask several questions why a poly B plumber considers REHAU PEX to be the perfect poly B replacement piping. First REHAU is a manufacturer of pipes such as PE, PP, OVC, and PEX. The company has in-depth, unmatched knowledge and experience of extrusion techniques. REHAU performs its compounding and blending of diverse ingredients under strict controls in the extrusion facility for the transformation of raw materials into high-quality finished product. The quality of REHAU PEXa pipes is higher than the international standards for performance.

What Is Crosslinked Polyethylene (PEX)?

PEX is the polyethylene (PE) that has gone through a transformation in the molecular structure while all the polymer chains are linked chemically, crosslinked (X) with one another to form a three-dimensional network. This, however, results in a flexible thermoset polymer with enhanced thermal, mechanical, and chemical properties.

Why REHAU Class Is Superior

In 1968, REHAU started the commercial crosslinking with the use of high-pressure peroxide method also referred to as PEXa. This process requires the addition of a small amount of liquid peroxide to the base high-density polyethylene (HDPE) pellets in a controlled facility at moderate temperature.

Next, crosslinking takes place from the melting and extrusion of the resulting compound from the combination of pressure developed within the extrusion machine and high temperature. The consumption of peroxide occurs in the resultant reaction. This process makes a higher degree of crosslinking possible. Consequently, REHAU PEXa pipes are crosslinked up to 85% level.

One unique feature of REHAU class in the classes of PEX piping is its ability to expand under high pressure and return to its normal shape after the removal of the pressure. This is a high level of flexibility that will allow the expansion of water that freezes within it. The non-crosslinked pipe is rigid and has a high resistance to pressure before initial expansion- the reason for its deformity and forceful expansion that leave it forever weakened and changed.

Here are some of the reasons REHAU class is considered superior:

Exceptional Flexibility

PEX is the best Poly B™ replacement because of its ability to withstand impacts and freezing. And when there is surge pressure, it withstands it better than CPVC, steel, or copper without resulting in water hammer.

Excellent Strength

It has superior strength and top-of-the-range pressure ratings.

Resistance to Chemical

REHAU PEX has a high resistance to chemicals such as urethane foam, silicone, latex paints, glycols, and most acids and bases.

Resistance to Corrosion

It is not vulnerable to corrosion from water or soil, and it does not leak no matter how little.

Ease of Installation

Most Poly B™ plumbers confirm that REHAU PEX pipes are easy to install due to their flexibility and superior joining technique. Moreover, they require no glue or soldering, and they do not produce a flame.

Read: Poly B™ Drywall Repair – Best Practices


REHAU PEX pipes have been in existence for more than 40 years, and they are the perfect poly B replacement solution.

Environmental Friendliness

PEX is highly environmentally friendly compared to other materials. Here are the reasons:

  1. No use of chlorine in its production
  2. Requires no mining of ore as with copper due to the abundance of PE
  3. Energy efficient and faster delivery of hot water
  4. Reduction of heat loss and condensation as with copper pipes
  5. Lightweight and cheaper cost of transportation
  6. Proven durability and longevity

PEX is acceptable for piping projects while Poly B™ is not accepted any longer. As a result, PEX triumphs as the most suitable Poly B™ replacement and it is hard to find any Poly B™ plumber who completely understand all the classes of PEX piping like Urban Piping Ltd.

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