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U.S. infrastructure has improved over the last few years, but it hasn’t been nearly enough. The 2021 infrastructure report card by the American Society of Civil Engineers, for example, showed deficits in areas such as drinking water, wastewater, stormwater, and energy infrastructure (1). Just as significant are the issues surrounding aging infrastructure during extreme weather events such as the deep freeze that hit Texas in early 2021.
The problem with infrastructure development often comes down to upfront cost. How can lawmakers create solutions that not only solve our infrastructure problems, but also remain cost-effective in the long-term? One solution is to rethink the materials of choice for these construction projects. Innovations in thermoplastics and improved manufacturing techniques have heralded the arrival of highly durable and long-lasting products like high-density polyethylene (HDPE) pipes.
Today, these pipes are manufactured with resins like PE4710 and PE100-RC, offering a piping trifecta of durability, flexibility, and chemical stability. With these qualities, HDPE pipes offer superior performance over competing piping materials as well as enhanced protection against 100-year events such as earthquakes, floods, and deep freezes. More importantly, unlike other materials, HDPE pipes are highly recyclable and excels in most metrics of life cycle assessments, which also makes them an environmentally friendly choice.
HDPE is a highly durable and stable piping material
Durability and chemical stability are two of the most important qualities to look for in a candidate material to replace our aging piping infrastructure. A material like HDPE, which offers a unique combination of durability and flexibility in a lightweight package, allows installers to utilize cost-effective and ecologically friendly installation methods such as horizontal directional drilling (HDD). HDD allows also allows installers to install pipes under roadways and other obstacles with minimal disruption.
HDPE pipes are an all-in-one package. Unlike other materials that may require additional products to incorporate corrosion or chemical resistance, HDPE is innately stable against most common forms of corrosion or chemical attacks found in water and wastewater applications.
By using durable and stable products like HDPE pipes and fittings, installers can greatly reduce the cost of the project throughout its expected service life. While other piping materials may require frequent maintenance, HDPE pipes remain as effective years into its service life. Furthermore, HDPE pipes resist fouling and other forms of buildup within the pipe that significantly decreases the flow capacity of other piping materials years into service.
HDPE pipes have a history of high performance
Rehabilitating a piping system to improve U.S. infrastructure should address more than one long-term goal. The new piping system should be durable enough to withstand 100-year events like extreme weather or earthquakes. HDPE pipes have a rich history of performance under adverse conditions. In one post-disaster case study analyzing various piping systems and their respective materials throughout Kobe, Japan after the 1995 earthquakes, the authors found that the HDPE pipes performed very well. The failure rate was virtually 0, compared with other materials with failure rates ranging from 0.26 to 1.1 failures per mile (2).
Table 1. Performance report of different U.S. piping materials from reference 2.
|Pipe Material||Number of Failures||Total Length (in miles)||Failure (per 100 miles per year)|
* Other Materials include Reinforced Concrete and Asbestos Cement.
HDPE pipes are also highly versatile. Because they can be used in many applications, investments in HDPE as a piping material can contribute significantly across multiple sectors. For example, large diameter HDPE pipes have been used in the construction of sea-based fish farms (aquaculture).
HDPE pipes score high in life cycle assessments and are highly recyclable
Choosing the right materials and products for future infrastructure projects should also consider the environmental cost. Fortunately, HDPE pipes are a sound investment from an environmental perspective. A life cycle assessment of various piping materials showed that HDPE pipes outperform competing products when it comes to global warming, acidification, eutrophication, ozone depletion, and smog formation. Additionally, HDPE pipes produce the least amount of solid waste and use the least amount of water (3). Finally, since HDPE pipes are easier to maintain and last longer, the total amount of construction activity and maintenance in the impacted area is minimized, which helps protect habitats.
Another important factor is the recyclability of HDPE pipes, which is relatively easy compared with other materials. Pipes can be shaved down and reprocessed into pellets to be used later in other industrial applications. Although consumer plastics (single-use applications) have given the material a bad reputation, plastics in industrial settings have played an essential role in protecting the environment. From landfill liners that protect the environment from leachate to highly durable pipes that keep sewage within the system until it can be treated, HDPE and other plastics have become some of the most important materials in protecting our environment. If paired with HDPE fittings, installers can weld leak-free joints that significantly reduce water loss.
As changing climate patterns continue to trigger extreme weather events that were previously expected only once every 100 years, the need for durable and robust infrastructure becomes clear. Although infrastructure development and rehabilitation should be at the top of every city’s to-do list, choosing the right materials and products is essential for creating long-lasting and cost-effective solutions. High-density polyethylene has proven itself over the years across many applications, especially in piping systems. For this reason, cities should consider HDPE pipes and fittings for the city’s new infrastructure.
- 1. Infrastructure Report Card. https://infrastructurereportcard.org/infrastructure-categories/.
- 2. 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 28 April 2021. https://www.waterrf.org/system/files/resource/2019-07/4485_1.pdf.
- 3. Lifecycle Assessment of North American Stormwater Pipe Systems. https://plasticpipe.org/pdf/tr-53-2021.pdf.