Apr. 19, 2022
Surveyed sewer system operators and consulting engineers from across the United States indicated that HDPE and PVC ranked first or second in most categories. Both types of pipe have their advantages and disadvantages and appeal to many contractors and project owners because of their wide range of applications. The choice of piping material usually determines the choice of fittings that will be used in a given project. However, there are some applications and situations where HDPE fittings can be better utilized.
Below, we examine the differences between polyvinyl chloride (PVC) and high-density polyethylene (HDPE) piping, describe ideal applications for HDPE fittings, and review the benefits of sourcing most HDPE pipe and fittings from the same material.
When comparing PVC to HDPE, it is first important to recognize that both materials offer many advantages over other more traditional pipe options made of concrete, iron, steel or copper. Most municipalities once relied on traditional pipeline materials to build their water infrastructure, but this has changed as alternatives have become available. Traditional pipeline materials also suffer from leaking pipe joints, corrosion damage to pipes, and general wear and tear.
On the other hand, thermoplastics such as PVC and HDPE have a much longer service life than traditional pipeline materials. They are also less dense and therefore lighter and cheaper to transport. pvc and hdpe also exhibit high tensile strength and are highly resistant to electrochemical corrosion. While there are many similarities between these two thermoplastics, there are some key differences.
HDPE Gas Pipe
PVC is described as a harder, stronger material that has both advantages and disadvantages. A key positive is that less PVC material is required than HDPE to manufacture pressure piping at target pressure levels. Because of its stiffness and strength, PVC can be directly attached to mechanical valves, non-plastic fittings and many types of connections. However, its lack of flexibility means that PVC requires a longer bend radius than HDPE pipe.
When comparing PVC to HDPE, it is first important to recognize that both materials offer many advantages over other more traditional pipe options made of concrete, iron, steel or copper.
HDPE is known for its high strength-to-density ratio, flexibility and chemical stability, making it the best choice for both pressure and non-pressure piping applications. While it does require more material to achieve the same pressure rating as PVC pipe, HDPE has the distinct advantage of multiple methods of achieving a leak-free system through hot-fusion joints and the use of specialized fittings.
One of the biggest problems with mechanically connected conventional piping is the high incidence of background leaks - water leaking out of the pipe through the pipe joints. It is estimated that approximately 14% of drinking water is lost to background leaks each day in the U.S. This represents a loss of more than 12 million gallons of water per year in a city of 100,000 people. HDPE piping and its associated fittings and connections offer distinct advantages because they can be used to create leak-free joints that prevent background leaks.
HDPE Dredge Pipe
For example, a transition fitting is a permanent, factory-made joint that connects HDPE pipe to any other pipe material. The fitting is held in place by a circumferential compression fit around or into the other piping material by an O-ring sealed HDPE pipe. Transition fittings allow HDPE pipe to be connected to steel pipe, ductile iron pipe, PVC pipe, etc. Modern options exist to utilize fusion welding as well.
Traditional methods require butt welding, which creates a fusion joint that is leak-free and as strong as the pipe. During repairs or special services that require modifications to inaccessible pipes, installers can use electrofusion joints to connect new pipes and fittings. Electrofusion is a computerized fusion process that eliminates most possibilities for human error while requiring smaller assembly access points.
HDPE piping is available in more types of fittings and connections, in part because it offers greater flexibility than PVC and traditional piping materials. While the lack of stiffness means HDPE pipe can be transported and installed more easily, it also means that special fittings are sometimes required to connect the pipe to various components. To overcome this drawback, installers should consider sourcing pipe and fittings of the same material.
One of the biggest advantages of sourcing pipe and fittings from the same material is that you can ensure optimal interoperability and minimize the risk of time-wasting modifications to accommodate any differences between products. Some manufacturers go a step further and offer training and specialized equipment to use their products.
