Hello, I’m Abby and welcome to the AGRU America podcast. Today, we will continue to explore some of the concepts discussed in the recently published blog titled: “The economic edge of HDPE pipes for water systems.”
Abby: Thanks for joining me today, Cody. Today’s topic is HDPE pipes for water systems and the economic benefits that come with them. What did you think about the blog?
Cody: I think water conservation and framing its challenges from an economic perspective is a good strategy in motivating change in a positive direction. It was quite eye opening to see that piping is a significant aspect to this problem.
Abby: I think so. In the article, we discuss costs in terms of water that is wasted due to our aging infrastructure.
Cody: Yes, I saw some of those statistics—the costs are quite staggering. Nearly a trillion dollars to maintain and expand our existing infrastructure to meet demand over the next few decades. How exactly can HDPE pipes help in this area?
Abby: The idea is to reduce long-term costs and HDPE pipes have the potential to do exactly that. They are lighter in weight compared with traditional piping materials, which reduces transport and installation costs, and they are flexible and capable of being fusion welded to specialized fittings to create a water system with zero leaks.
Cody: Background leakage is mentioned in the article several times, what is it and why is it significant that HDPE pipes can be joined in ways that prevent background leakage?
Abby: I think it’s important to look at existing infrastructure and the impact background leakage has in contributing to waste. There have been extensive studies done by organizations such as the Water Research Foundation, Plastic Pipes Institute, and others in studying the extent of background leakage. Essentially, what they have found, is that for a city with the infrastructure to support a population of 100,000 people, about 12 million gallons of water is lost to leaks every year. And that’s pretty much the definition of background leakage; water leaking from joints.
Cody: OK, so when AWWA say that HDPE pipes form leak-free joints, do they really mean zero? How is this possible?
Abby: HDPE pipes fall under the category of thermoplastics, a polymer material that offers a high strength to weight ratio, high chemical resistance, thermal resistance, among other benefits. Another, perhaps better known, example of a thermoplastic is PVC, which is also used to create pipes. While both pipes share some properties, such as their chemical resistance, HDPE pipes differ in some ways from PVC, but one of the most significant differences is that HDPE is more flexible than PVC. This high flexibility and strength enable the pipe to be joined to fittings and connectors in ways that create leak-proof seals. One of the most reliable methods is using fusion welding with something like an electro-coupler.
Cody: How easy is it to use these fittings and joining them with welding?
Abby: It is definitely possible, through poor installation, to create a leaky joint with HDPE pipe. So, it isn’t foolproof. But with proper training and QA, it should be relatively straightforward for most installers. I’ll a link a video of the standard procedure that is outlined in the report we reference in our article: https://www.youtube.com/watch?v=RPsQhLrw-_0
Cody: It seems like we should be using HDPE across the board, why hasn’t that been the case?
Abby: There are three major factors: Costs, availability, and awareness. When it comes to costs, we have to recognize that HDPE pipes do carry higher upfront costs when compared with traditional piping materials like concrete and ductile iron.
Cody: Do the benefits of HDPE pipes offset its higher initial cost?
Abby: For the most part, they should. If the pipe is properly installed to create leak-free joints across the system, the cost-benefit picture begins to shift in favor of HDPE pipes over time. The scales further tip in the favor of HDPE when you consider the pipe’s high chemical resistance, which means fewer situations calling for maintenance and repair—a problem that plagues our existing infrastructure.
Cody: Going back to the factors that have affected HDPE pipe usage in the United States; what did you mean by availability?
Abby: Well, until now we have been discussing pipes in sizes that are typically used for water systems within a city. However, there are other use cases that require pipes of much higher diameters—wastewater treatment facilities and desalination plants are two examples. In the past, HDPE pipes were simply not available at the sizes required for core components in these constructions. That has changed recently.
Cody: So, although these XXL HDPE pipes do now exist, not everyone knows about it.
Abby: Exactly. But with more reports like the one published by the Water Research Foundation, it is only a matter of time before more cities begin to incorporate HDPE pipe into their city planning.
And with that, we come to a close with this podcast. A big thank you to Cody for joining me today for this discussion. To our listeners, thank you for tuning in. We hope you’ve enjoyed this podcast. If you have any feedback or topic requests, please do not hesitate to reach out to us on the web at AGRU America dot COM.
- Video: https://www.youtube.com/watch?v=RPsQhLrw-_0
- Najafi, A. Habibian, and V. F. Sever, “Durability and Reliability of Large Diameter HDPE Pipe for Water Main Applications.” Water Research Foundation. (2015). Accessed online 3 May 2019. http://www.waterrf.org/PublicReportLibrary/4485.pdf.
- Ambrose et al., “Life Cycle Analysis of Water Networks.” Plastic Pipe Institute. Accessed online 3 May 2019. https://plasticpipe.org/pdf/life-cycle-cost-study.pdf.
- “Leakage Calculator.” Alliance for PE Pipes. Accessed online 3 May 2019. http://www.pepipe.org/leakage-calculator.
- “Desalination Worldwide.” Accessed online 3 May 2019. https://www.hbfreshwater.com/desalination-worldwide.html.
- Hiltzik, “Desalination plants aren’t a good solution for California drought.” LA Times. (2015). Accessed online 3 May 2019. https://www.latimes.com/business/hiltzik/la-fi-hiltzik-20150426-column.html.
- S. Watson, “The Advantages of Industrial-Municipal Wastewater Treatment.” Water Poll. Contr. Fed. (1970). Accessed online 3 May 2019. https://www.jstor.org/stable/25036469?seq=1#page_scan_tab_contents.