FREQUENTLY ASKED QUESTION

 How long has PEX been used?

What is PEX?

PEX is cross-linked Polyethylene. Through one of several processes, links between polyethylene macromolecules are formed to create bridges between PE molecules (thus the term "cross-linked). This resulting molecule is more durable under temperature extremes, chemical attack, and resists creep deformation, making PEX an excellent material for hot water applications (up to 200° F).

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 How long has PEX been used?

PEX was developed in the 1960s. PEX tubing has been in use in many European countries for plumbing, radiant heating and snow melt applications since that time. PEX was introduced in the United States in the 1980s, and has seen significant growth in market demand and production.

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What are recommended uses for PEX?

PEX 's flexibility and strength at temperatures ranging from below freezing up to 200 degrees Fahrenheit makes it an ideal piping material for hot and cold water plumbing systems, hydronic radiant heating systems, snow melting applications, and, even ice rinks and refrigeration warehouses.

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Can PEX be used under the slab?

Yes. The flexibility of PEX allows it to be supplied in coils meaning installations under the slab can be made with a single, continuous length without the need for fittings under the slab. PEX is not affected by concrete, or chemicals in concrete (it is commonly encased in concrete for radiant floor heating). PEX, however, must be sleeved when penetrating a concrete slab.

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Will PEX systems help save on utility bills?

Yes. Home run or manifold plumbing systems utilizing PEX tubing can substantially reduce water and energy consumption in a home. The home-run concept provides dedicated direct lines from the manifold to the fixtures, reducing the amount of water that must be purged from the lines to get hot water at the fixture. Direct lines can be sized to the fixture requirements, further reducing the amount of time to wait for hot water. Faster hot water delivery reduces water waste and the amount of times the water heater must cycle to supply hot water.

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What joining systems are available?

There are several methods of connecting PEX, all of which involve mechanical fittings. There are two approved standard specifications for PEX connections: ASTM F 1807 and ASTM F 1960. Both reference mechanical insert fittings. The crimp fittings specified in ASTM F1807 are the most widely used. Other fitting systems, including insert and outside diameter compression fittings, are also available. PEX cannot be joined by solvent cement or heat fusion methods.

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How long can PEX be exposed to sunlight?

PEX tubing is not intended for outdoor applications and must be stored in a covered environment not exposed to direct sunlight. Maximum UV exposure is no more than 60 days.

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What are temperature limitations for PEX?

PEX tubing can be used up to 200° Fahrenheit for heating applications. For plumbing, PEX is limited to 180° F. Temperature limitations are always noted on the print line of the PEX tubing. Recommended 140 max for safety and conservation

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How are PEX systems tested for leaks?

PEX plumbing and radiant heating systems can be pressure tested using either water or air to check for leaks. Follow manufacturer's instructions.

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How soon after installation can you pressure test a PEX tubing installation?

PEX  systems can generally be tested immediately after the installation is complete. There is no wait time for glue to dry or joint to cool off. Weather should be considered and manufacturer's instructions followed in cold weather.

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Is PEX freeze-break resistant?

PEX piping is freeze damage resistant and can expand and contract as water freezes and thaws within the tubing. No tubing material is freeze-break proof, however, and PEX should be installed using the same locally-prescribed insulation requirements to prevent freezing of any plumbing system.

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How do I thaw PEX lines?

When water freezes inside PEX tubing, it can be thawed using a hair dryer, warm wet rags or heat tape, taking care not to overheat the tubing beyond it's maximum recommended temperature.

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Can PEX be joined with solvent cement?

No. PEX cannot be joined with solvent cement, or heat fusion. PEX is installed using only mechanical fittings either inserted in or around the tubing or by compression fittings 

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