By Shell Polymers on Feb 25, 2021
Did you know that 20% of all plastic produced is used in construction due to its extended lifespan and durability?1 When HDPE was first introduced more than 70 years ago, it had a low crack resistance and was seen as an undesirable material to use for gas applications. Over time, the slow crack growth resistance of HDPE has increased and it is now seen as a highly-desirable alternative to materials that rust or crack easily.
Materials like copper, ductile or cast iron, concrete, and clay are still used in water and drainage applications. These materials have their share of benefits but let’s take a closer look at the advantages HDPE plastic offers over these alternate materials.
Benefits of HDPE for Water, Gas, and Oil Pipe Systems
HDPE is commonly known for being an affordable material and highly resistant to chemicals, solvents, and other environmental stresses. It’s a lightweight plastic that has a 100-year life expectancy, which is nearly double the life expectancy of many alternative pipe materials like copper2 and clay3. Plus, HDPE is corrosion-resistant and highly resistant to bacteria and solids buildup known as tuberculation. Because of this, HDPE pipe should retain its full flow capacity for its entire life.
Higher Strength and Durability
HDPE is lauded for its strength ratings, but its true differentiators show up in events where outside stressors like rain, wind, seismic activity, heat, and cold cause the pipe’s material to flex.
HDPE’s failure rate in these events is 0.00001%, making the material great for stressful environments like oil applications. It also provides the benefits of not rusting, mineral tuberculation resistance, and abrasion resistance which would help reduce the chances of these breaks.4 With regards to durability, HDPE can also withstand and dampen shock waves more than other pipe materials, making it highly resistant to water hammer and useful for rugged environments.5
More Sustainable Production
Sustainability is a growing concern for pipe extruders when it comes to the materials they use. HDPE has a small carbon footprint beyond the creation of the material.6 Since HDPE is lighter than heavy materials like copper, concrete, and ductile or cast iron, it is less expensive to transport, saving on gas, and energy usage. Once it reaches end-of-life, HDPE is also 100% recyclable, while the disposal of other pipe materials could pose substantial environmental and human health hazards.
Learn more about how a sustainable future takes innovation and drive
Evaluate HDPE Against Other Commonly-Used Pipe Materials
HDPE vs. Copper Pipes
There is little argument around the tried-and-tested uses of copper pipes. Copper has been used for hundreds of years and it's great for discouraging microbial growth. However, copper is not corrosion-resistant as HDPE is, meaning that it can corrode over time. Once copper pipes start to corrode, it can leach into the water supply and contaminate it.7
While it has been a popular choice for piping applications, it is naturally heavier than HDPE and therefore more costly to transport as well. Copper pipes are also more expensive and less flexible than HDPE pipes. They are also susceptible to sweating that can lead to mold or mildew issues and they may burst if water freezes inside the pipes.8 Copper pipes are also not as eco-friendly due to the toll copper mining and manufacturing takes on the environment, something environmentally-conscious buyers will need to take into account.9
HDPE vs. Clay Pipes
Even as recently as the 1990s, clay was a popular pipe material for municipal plumbing systems. Over the last few decades, plastic has replaced clay as the main sewer pipe material. However, clay pipes are still being used as sewer drain lines for many homes. Its popularity comes from the fact that it’s made from organic materials and clay is unaffected by the acids found in wastewater.10
When compared to HDPE, the cons of clay heavily outweigh the pros. If you’ve ever taken a pottery class, you’ll know that clay is a brittle material. For a material being used as a sewer pipe, most companies want a material that won’t break when pressure is applied or if the ground shifts.
Clay pipes have also been susceptible to roots growing into them, leading to blockage or leaks of wastewater, something other pipe materials don’t experience.11 It is also an expensive material to use in piping applications and transporting it is difficult due to its heavy weight and fragility. Repairs and installation are also more expensive compared to working with HDPE as workers must be immensely careful while handling the pipes.12
HDPE vs. Concrete Pipes
Concrete pipes have been popular choices for contractors due to its lifespan and durability. Like HDPE, concrete can withstand high-pressure conditions without losing integrity. Unlike HDPE, concrete must be maintained on a regular basis. Buildup does occur from sewage materials when using concrete pipes and that must be dealt with in order to ensure optimal usage. It’s common to have regular inspections and assessments of concrete pipes, leading to an additional cost when using the material. It is also susceptible to breaking when being handled, much like clay, so installation requires the proper equipment and expertise, which results in additional costs as well.13
HDPE vs. Iron Pipes
In the first half of the 20th century, ductile or cast iron pipes were extremely popular. They are strong and durable, offering a long-lasting choice for underground applications. Iron is also sound and heat-resistant, ensuring less noise from liquids moving within pipes. However, all iron pipes are susceptible to rust. If these pipes rust completely, they can be replaced with plastic pipes that do not rust at all. So while they used to be a leading pipe material for their durability and affordability, their weight and low rust-resistance have iron pipes being phased out in most modern applications.14
There are a variety of materials used for underground piping applications. Every material has its benefits and setbacks but as plastic piping becomes more popular and additional data is collected on its usage, the comparisons become more clear. HDPE is a great choice for pipe applications and will continue to give traditional materials a run for their money in the coming years.