September 11, 2024

Understanding the Print String on Uponor PEX-a Pipe 

By David Nickelson

While the print string on Uponor PEX-a pipe may look like a confusing thread of letters, numbers, and codes with no meaning, this is not the case. Understanding the information on PEX pipe print string can help installers ensure consistent, quality, and efficient pipe installation in the appropriate application. 

 

Looking at the pipe in the image above from left to right, we see that the name of the product is listed first. In this case, the product name in the photo is Uponor AquaPEX®. 

After the product name is the material family. The image above shows “PEX” as the material family, followed by four numbers. The first number is the pipe’s chlorine-resistance rating for either continuous or intermittent recirculation of water at specific operating temperatures. 

For PEX pipe, there are four different ratings. 

• 0 means no rating 
• ​1 means the pipe can be exposed to chlorinated water 25% of the time at 140°F (60°C) and 75% of the time at 73.4°F (23°C)  
• 3 means the pipe can be exposed to chlorinated water 50% of the time at 140°F (60°C) and 50% of the time at 73.4°F (23°C)  
• 5 means the pipe can be exposed to chlorinated water 100% of the time at 140°F (60°C) with 4 parts per million (ppm) chlorine 

In the image above, the pipe has a chlorine rating of “5”. This means it is approved for use in continuous recirculation of 4 ppm chlorinated water at 140°F (60°C) operating temperatures.    

The second number in the string of four numbers is the rating for exposure to ultraviolet (UV) light. In total, there are four different UV-resistance ratings.  

• 0 means no rating 
• 1 means a one-month rating 
• 2 means a three-month rating 
• 3 means a six-month rating 

The pipe pictured above has a UV-resistance rating of one month (maximum exposure to UV light of one month). This is an important point for installers to know so they can plan proper storage in a timely manner. Extending beyond this time will have an impact on pipe quality, reliability, and warranty coverage. 

The last two numbers on the string are the Hydrostatic Design Stress (HDS) rating, which determines the allowable stress a pipe can tolerate. In total, there are three different HDS ratings.   

• 06 means a rating of 630 psi 
• 08 means a rating of 800 psi 
• 10 means a rating of 1,000 psi 

The pipe above has a 06 rating, so it is designed and manufactured to withstand 630 pounds of pressure per square inch of the pipe at a temperature of 73.4°F (23°C).   

Next in the print string sequence is the pipe size. On the AquaPEX sample image above, the pipe has “1/2 IN”. This makes it easy for installers to ensure they have the right size pipe for their job. Pipe size is an important determinate of water flow and friction. Smaller pipes have a higher rate of friction and a lower flow rate, while larger pipes have decreased friction and a higher flow rate. 

After pipe size is the Standard Dimensional Ratio (SDR). This defines the ratio of the pipe’s outer diameter to its wall thickness. For example, the pipe listed in the image has an SDR of 9, signifying the pipe’s outer diameter is nine times its wall thickness.  

Why is this important? Typically, a pipe with a lower SDR number has a higher allowable rate of pressure, a thicker wall, and will be heavier. A higher SDR rating would have a lower pressure rating, less material, a thinner wall, and less weight per foot. In general, a pipe with an SDR of 9 is suitable for many residential and commercial plumbing and hydronic piping applications, because it offers a balance of strength and flexibility. It is also a common specification for plastic pipes. 

Following the SDR is the UB number, which provides information about the pipe’s manufacturing process. The next section states “POTABLE”, which means the pipe is intended for water approved for human consumption and use (drinking, washing, etc.). After that section comes the applicable codes, standards, and listings. 

Uponor PEX-a pipe includes ASTM F876 (U.S.) and CSA B137.5 (Canada), which qualifies the design and manufacturing requirements for PEX pipe. The print string then features other standards and listings, including fitting system information (ASTM F1960, F1807, F2098, and ASSE 1061). 

For Uponor AquaPEX, specifically, the pipe is designed, tested, and manufactured to following codes, standards, and listings: 

• NSF 14: Plastic pipe system components and related material 
• ​NSF 61: Drinking water system components and health effects 
• ASTM F876: Drinking water standard for PEX tubing 
• ASTM F877: Standard PEX hot and cold-water distribution
• ASTM F1960: Standard for cold expansion fittings 
• ASTM 2023: Standard for PEX oxidative resistance and system to hot chlorinated water 
• ASTM E84: Standard for surface burning of building materials 
• CAN/ULC S102.2: Surface burning characteristics of flooring, floor covering, and miscellaneous materials and assets 
• ASTM E119/UL 263: Fire tests of building construction and materials 
• ASTM E814/ULC S115: Standard test method for fire tests of penetration firestop systems 
• CSA B137.5: Crosslinked polyethylene (PEX) tubing systems for pressure applications 
• CSA B214: Installation code for hydronic heating systems 
• UL 1821: Thermoplastic sprinkler pipe and fittings for fire protection service 
• U.P. Code: Compliance to the Uniform Plumbing Code 

This comprehensive list of regulatory requirements helps to ensure confidence in a product that is designed and manufactured to provide consistent reliability and long-lasting service. 

Be sure to review the print string on pipe. It is a resource that provides valuable information for product application and use. Understanding the letters, numbers, and codes will help to ensure consistency, quality, and efficiency in the appropriate applications.