Recent introduction of PP into the sanitary sewer market should be cause for concern to wastewater utilities. Unsupported claims about performance, lack of rigorous studies and testing, questions regarding joint integrity, reduced safety factor, limited options for fittings and lateral connections, all point to the need for caution when considering PP alternatives over PVC pipe.

Thermoplastic materials have different engineering properties and standards, and it's important for engineers, contractors and sewer departments to recognize them. Otherwise they risk compromising long-term performance.

Uni-Bell's PVC vs. PP comparison sheet (click here) summarizes these differences, ranging from why bell stiffeners are required for PP, to allowable deflection limits and the corresponding safety factor – confirming PVC pipe's superior performance.  

Supported by over 40 years of standards and testing, PVC pipe offers exceptional joint integrity, low maintenance and a high safety factor, backed by stringent mandrel and low-pressure air tests. With a broad assortment of fittings for connections, which help avoid compromising system integrity through use of cut-in fittings, PVC pipe is available in a wide array of options suitable for the most difficult applications.

With more than one million miles in service,  and manufactured in sizes ranging for 4-60 inches, PVC is the most widely used material for gravity sewer pipe with an estimated market share in excess of 80%.

The quality and performance of PVC have been validated by countless universities, government agencies, engineers, installers and utilities.  As well,  it was ranked highest in a 2010 buried pipe market survey by Trenchless Technology  Magazine  and rated as the most commonly specified, easiest to maintain and longest-lasting pipe material.  See pages 8-11 of the study by clicking on the following link:

http://www.trenchlessonline.com/pdfs/2010_Pipe_Materials_Guide.pdf

When compared to PVC, PP just doesn't measure up. For proven performance, sustainability and cost effectiveness, PVC is the material of choice for water and wastewater systems.

If you have any questions about the comparison sheet, please feel free to contact us.

Industry expert and PVC Pipe Association Regional Engineer Steve Cooper addresses use of PVC in deep excavations.

Welcome to my blog.

Having been involved with utility operations for over 20 years and six years as a regional engineer, I know from experience how utilities make decisions regarding materials used for underground water and sewer pipe systems.

And from my experience, I can say the reluctance some utility managers have to using PVC as a piping material stems from misinformation or a lack of information about the product.

The reluctance to use flexible pipes in deep bury applications is a case in point. Some engineers will insist on using iron over a certain depth, although the rest of the sewer main is PVC, because they fear PVC won’t hold up under large dead loads.

Unfortunately, such practices rest more on myth than engineering principles. In fact, many cities across the U.S. have reviewed the engineering of flexible pipe design and properly concluded that PVC pipe’s stiffness and deflection limits are more than adequate for deep bury projects. Numerous case studies confirm PVC can be buried at depths in excess of 40 feet.

The attached article and bury depth graphs provide a background and understanding of why PVC is well suited for such applications (click here).

I invite you to explore our web site and visit my blog often to learn about the tremendous value, environmental attributes, and exceptional performance of PVC pipe.

To connect to my blog, bookmark this page or link our Pipe Issues Blog to your RSS feed program.

Steve