Cross-Linked Polyethylene (PEX) piping is a durable and reliable solution that is often used for hot- and cold-water plumbing. It’s so dependable that PEX tubing is even used for heating and cooling, residential fire protection systems and, in some parts of the world, natural gas piping. One of PEX’s properties is its tolerance to high pressures; thus, here we will discuss PEX pressure ratings and related characteristics.
Why Is PEX Used?
Cross-linking of polyethylene molecules creates chemical bonds that improve temperature performance under load and provide resistance to cracking under environmental stress. This makes pipes abrasion-resistant as well. The three types of PEX piping are PEX A, PEX B, and PEX C. The most resistant to burst pressure is PEX A, which can hold up in pressures up to 500 pounds per square inch (psi). It’s also often used where extremely cold temperatures are likely.
PEX Pressure Rating Examples
PEX tubing has a standard hydrostatic pressure rating of 160 psi at 73℉ (this is a 630 HDB rating, which applies to all PEX tubing sold in the U.S.). At 180℉, it has a pressure rating of 100 psi. However, there are different types of PEX tubing made by various manufacturers. This makes it a challenge to develop one standard set of pressure ratings. The actual ratings are identified in the product literature and anywhere pressure ratings are listed.
The pressure rating also heavily depends on the material used and the pipe’s wall thickness. But another important factor is pressure drop. It is the difference in total pressure between two points due to friction, which creates a resistance to flow as a fluid passes through a tube. Pressure drop can have a significant impact on flow across a plumbing network.
The following table identifies pressure drop when accounting for flow rate and pipe length. The numbers represent psi values per 100 feet of tubing.1
| Flow Rate
(In Gallons per Minute (GPM) |
PEX Tubing Size | ||||
| ⅜” | ½” | ⅝” | ¾” | 1” | |
| 0.5 | 2.50 | 0.51 | 0.21 | 0.05 | 0.02 |
| 1.0 | 7.50 | 1.70 | 0.71 | 0.34 | 0.10 |
| 2.0 | 26.1 | 5.30 | 2.12 | 1.02 | 0.35 |
| 3.0 | 54.1 | 11.0 | 4.36 | 2.10 | 0.63 |
| 4.0 | 18.4 | 7.36 | 3.53 | 1.06 | |
| 5.0 | 27.4 | 11.0 | 5.26 | 1.58 | |
| 6.0 | 38.1 | 15.3 | 7.30 | 2.19 | |
| 7.0 | 20.1 | 9.63 | 2.89 | ||
| 8.0 | 25.6 | 12.3 | 3.68 | ||
| 9.0 | 31.7 | 15.1 | 4.55 | ||
| 10.0 | 18.3 | 5.50 | |||
| 11.0 | 21.7 | 6.52 | |||
| 12.0 | 25.4 | 7.63 | |||
| 13.0 | 8.81 | ||||
| 14.0 | 10.1 | ||||
| 15.0 | 11.4 | ||||
Other Important Metrics
It’s important to note PEX pipes aren’t only rated based on pressure. They’re also identified by their chlorine resistance, the highest rating for which is five. Another quality you’ll see listed is ultraviolet (UV) resistance. Class 3, the highest, means the pipe has a six-month UV resistance rating.
In addition, PEX pipe is preferred for the range of applications it can serve. It works for water service lines from ½ to 3 inches and meets residential fire protection standards. Also, it can be used under floors/walls/ceilings for radiant heating and cooling, underground as transmission piping, in geothermal ground loops, and for outdoor snow and ice melting.
Learn More with Village Plumbing
Village Plumbing provides high-quality repiping and other home plumbing services in the Houston area. While PEX tubing is easier to install than other pipe materials, a plumbing specialist should handle all installation and repair work. We work within your budget and schedule and stick to a project management plan. Flexible financing options are available. To request service or inquire about PEX pressure ratings, use our online contact form or call 713-526-1491.