HDPE and HDPE Pipes: A User’s Guide

As a construction professional, you are likely to find yourself requesting a quote or more information from plastic manufacturing companies in your quest to find a reliable supplier of HDPE pipes.

One way to ensure you will find the best supplier is to learn as much as you can about HDPE. Below is a crash course on HDPE and HDPE piping applications.

What Is HDPE
What Is HDPE

What Is HDPE?

HDPE stands for high-density polyethylene. It is a manufactured thermoplastic made by polymerizing the petroleum-derived organic chemical ethylene.

HDPE has various uses across a wide range of industries. HDPE is most commonly used in piping systems for both indoor and outdoor applications in building and construction. HDPE is also used in making food-grade bottles, jugs, and cutting boards.

Likewise, HDPE can be found in toys, playground systems, marine environment anti-skid surfaces, furniture, flower pots, cereal box liners, shampoo bottles, bleach bottles, trash bins, and chemical tanks.

Characteristics of HDPE

What makes HDPE a highly preferred plastic for various applications?

The following are some of the desirable characteristics of HDPE.

1. High Tensile Strength

HDPE is a high-density, flexible plastic with a tensile strength ranging from 23 to 29.5 megapascals at a 23°C reference temperature. Tensile strength is the measure of stress a material can tolerate without breaking.

Therefore, HDPE can stretch, bend, yield, and, overall, withstand a significant amount of stress before it breaks. This is why HDPE bottles, which are quite lightweight, can carry materials many times their weight without breaking. Case in point: HDPE milk jugs.

2. Chemical Resistance

HDPE has a high excellent compatibility rating with most chemicals and shows particularly robust chemical resistance to strong acids and bases. Chemical resistance is a material’s ability to maintain its integrity in the face of a chemical attack.

In other words, HDPE does not react with or soften even when exposed to a wide range of chemicals. HDPE’s excellent resistance to most chemicals makes it popular in applications that require corrosion-proof materials. Thus, HDPE often requires no special protective coating, even when used in slurry pipelines or mining treatment facilities.

3. Durability and Weather Resistance

An HDPE pipe has a life expectancy of 50 years or more. Of course, the greater the stress it is subject to and the greater its load, the shorter its life expectancy would be. Likewise, a pipe exposed to extremely fluctuating weather conditions may have a shorter lifespan.

That being said, HDPE has superior material durability and is a good choice when one requires durable, all-weather materials.

4. Scratch and Impact Resistance

HDPE has excellent impact and scratch resistance. A study found that it takes 50 J of energy to penetrate injection molded HDPE samples.

5. Minimal Water Absorption

HDPE has a water absorption rate of 0.005 to 0.01%. That is a significantly low moisture absorption rate. This is important because water can soften plastic. Water absorption can cause changes in plastic elasticity as well as its tensile and impact strength.

6. Mildew, Mold and Rot Resistance

HDPE has also been shown to have exceptional resistance to biological growth. A study conducted to determine the degradation rates of plastics indicates that HDPE in the marine environment has a half-life that ranges between 58 years for bottles and 1,200 years for pipes.

Resistance to microorganisms like mold and mildew is essential, especially in HDPEs used in food applications or in pipes that carry materials that must not be contaminated. Resistance to rot, meanwhile, helps ensure HDPE’s durability.

7. Malleability

HDPE can be worked into almost any shape or dimension required because of its outstanding malleability. It can be molded practically into anything.

8. Weldability

Even if you don’t have the exact HDPE pipe you need — for instance, you need a longer pipe or one with an irregular shape — you can weld HDPE pipes according to your requirements. Not only can it be cut and altered as needed; HDPE is also weldable.

HDPE Pipes: Applications and Standards

Piping is the most common use of HDPE in building and construction. The following are some of the ways by which HDPE pipes are being utilized.

Fluid Transport and Irrigation

HDPE pipes can be used in irrigation and to transport potable water and wastewater. In the energy and mining industry, HDPE pipes transport slurries, chemicals, toxic byproducts, and compressed gasses. In recreation, HDPE pipes are used to supply water to wave pools and water slides.

When using HDPE pipes to transport drinking water, raw or pre-treatment water, wastewater, runoff water, and water for other purposes, you want pipes that comply with International Organization for Standardization or ISO 4427 and European Standards or EN 13244. These define the standards for plastic piping systems for water, drainage, sewerage, and other general purposes.

Firefighting Applications

Engineering professionals often have to integrate firefighting systems into the structures they’re building. Firefighting equipment is an integral part of builds in chemical and energy companies and other industries.

HDPE pipes can be used in firefighting systems. An HDPE pipeline can be buried underground to serve as the mains with readily accessible fire hydrants. The pipeline then extends above-ground to feed sprinklers and other such automated fire-fighting equipment.

You want HDPE pipes that conform to ISO 4407 and American Water Works Association or AWWA 906 standard specifications for firefighting applications.

Drainage Applications

HDPE pipes can be used for drainage applications. The pipes are buried below-ground or above-ground and used for drainage applications involving water, soil, general waste, and chemical waste.

When looking for pipes to use for drainage applications, look for HDPE pipes that have been manufactured according to EN 1519 specifications.

Ducting Applications

You can also use HDPE pipes to create ducting systems, such as electrical ducting.

Pipes for this type of application can range from 50 mm to 315 mm in size, with a pressure grade or pressure rating of PN 6 (max pressure of 6 bar) or PN 10 (maximum pressure of 10 bar). The standard dimension ratio, or the diameter to wall thickness ratio, can be 26 or 17.

To ensure quality, look for pipes that have been manufactured according to ISO 4427 specifications.

Building With HDPE

HDPE is a chemically resistant, corrosion-proof, durable, and strong material with many applications. Piping is one of its most common uses.

If you need piping for water or substance transport, irrigation, drainage, firefighting, and ducting applications, consider using HDPE.