F.A.Q.
What are the recommended uses for PEX?
The strength and flexibility of PEX at temperatures ranging from 0° up to 200°F makes it the perfect piping material for hot/cold water plumbing applications, hydronic radiant heating systems, service lines and snow melting applications.
Is PEX a safe product for plumbing?
PEX is manufactured and tested to meet rigorous national consensus standards. Both the manufacturer and independent third party testing agencies conduct regular quality control evaluations to ensure that the product meets CSA and International standards. Compliance with these standards ensures the end user of its safety and quality. In addition, PEX is included in all of the major model plumbing codes used throughout the United States and Canada, and is HUD approved for hot and cold domestic water plumbing use.
Is PEX approved for use everywhere?
PEX is an approved material in all the current model plumbing codes. However, some jurisdictions may still be using older versions of these codes and may not have expanded the code to incorporate PEX piping. Contact your local authority (that has plumbing jurisdiction) to confirm that PEX tubing has been approved for plumbing applications in your area.
Can PEX be used under a slab?
Yes. The flexibility of PEX allows it to be supplied in coils, which means that installations under the slab can be made in a single, continuous length without the need for fittings. PEX is not affected by concrete. In fact, it is commonly encased in concrete for radiant floor heating. However, PEX must be sleeved when penetrating a slab.
Can PEX be used in underground cold-water service applications?
Yes. Although the high temperature resistance of PEX makes it particularly well suited for hot and cold interior plumbing applications, it also makes an excellent underground water service piping. The new AWWA C904 standard also applies to PEX used in this application. PEX can be installed using the same fittings suggested for SDR-9 sized copper tubing.
Can PEX be used in above ground outdoor applications?
No. PEX is currently intended for indoor and buried applications only and is not recommended for aboveground use outdoors. Short exposure to sunlight during construction is permitted, but shouldn’t exceed the manufacturer’s recommendations. Insure that the tubing is stored under cover, protected from direct sunlight if it can’t be kept in its original packaging.
How long can PEX be exposed to sunlight?
PEX tubing is not intended for outdoor applications and should be stored in a covered environment, unexposed to direct sunlight. Refer to manufacturer’s instructions to determine how long your pipe can be exposed to sunlight.
Will using PEX save me money?
Yes. PEX saves money in several ways.
For installers; PEX tubing is priced competitively and installing of flexible systems is faster because PEX pipe fewer directional fittings are required. Since most plumbing problems occur at joints, fewer fittings will reduce the likelihood for leaks, resulting in fewer callbacks.
For the homeowner; PEX tubing can significantly reduce water and energy use by using either a manifold plumbing system or a home run plumbing system. The home-run concept uses one dedicated line from the manifold to the fixture, reducing the amount of water that must be flushed from the lines to get hot water at the fixture. Direct lines can be sized to the fixture requirements, which will reduce the amount of wait time for hot water. The hot water will arrive at the fixture faster, which will not only reduce water waste, but the number of times the water heater will cycle to supply hot water.
What is the expected performance of a PEX water distribution system?
PEX is designed and tested to perform as well or better than any other material approved for hot and cold-water distribution systems. PEX is anticipated to perform as long as copper, CPVC or any other approved plumbing material.
What joining systems are available?
There are several methods for joining PEX and they all involve the use of mechanical fittings. The two approved standard specifications for PEX connections are ASTM F 1960 and ASTM F 1807. The crimp fittings specified in ASTM F1807 are the most widely used. Other fitting systems, including compression fittings, are also available. PEX cannot be joined by solvent cement or heat fusion methods.
What are the temperature limitations of PEX?
PEX tubing can be used up to 200° Fahrenheit for heating applications. For plumbing, PEX is limited to 180°F. Temperature limitations can be found on the print line of the PEX tubing. PEX is tested to, and can be used with, standard T and P relief valves that operate at 210° F and 150 psi.
How do you test PEX systems for leaks?
PEX plumbing and radiant heating systems can be pressure tested with water to check for leaks. Follow manufacturer's directions.
How soon after installation can you pressure test a PEX tubing installation?
Since there is no wait time for joints to cool or glues to dry, most PEX plumbing systems can be tested immediately after installation, but follow manufacturer’s directions, particularly in colder climates.
What sizes, lengths and packaging options are available for PEX?
PEX is available in 1/4" through 1" CTS (Copper Tube Size) and is packaged in coils or 20' straight lengths. Some tubing is color-coded, which means easily identifying the hot and cold lines. Coil lengths generally run to a maximum of 1000' and are available in a variety of shorter lengths.
What are manifold plumbing systems?
Parallel, home run or manifold systems are the plumbing equivalent of the breaker box for the homes electrical system. The manifold provides a common location from which all the plumbing fixtures are supplied. Some manifolds also provide shut-off valves for individual fixtures, which allow the consumer to shut the water off to each fixture individually, from a single location. The semi-home run manifolds, or termination manifolds, can supply the plumbing needs of a single room or a series of rooms, reducing the number of fittings required in the plumbing system. Using PEX in high performance manifold plumbing systems will take full advantage of its flexibility and cost effectiveness.
How are PEX systems sized?
PEX systems are sized just like other CTS plumbing materials such as copper or CPVC when used in a trunk-and-branch installation. PEX can be sized in manifold systems to meet the specific demands of each fixture, reducing water and energy waste in the home.
Is the thermal expansion and contraction of PEX a problem?
No. While PEX expands more than some plumbing materials, directional changes made with the tubing, and allowing some slack in the tubing during installation, will accommodate the expansion and contraction of the system if properly installed.
Is PEX resistant to freeze damage?
PEX pipe is resistant to freeze damage, typically expanding or contracting as water freezes or thaws within the pipe. However, no tubing material is freeze-break proof, and PEX should be installed using the same insulation requirements locally prescribed to prevent freezing of any plumbing system.
How do I thaw PEX lines if they do freeze?
If water freezes inside PEX pipe, it can be thawed using heat tape, a hair dryer, or warm, wet rags, taking care not to overheat the tubing beyond the maximum recommended temperature.
Can PEX be joined with solvent cement?
No. PEX is installed using either mechanical fittings or compression fittings. Unlike rigid piping materials, PEX cannot be joined using solvent cement, glues or heat.