December 2020, Vol. 247, No. 12


Plastic Pipe Remains a Key to Quality Infrastructure

Infrastructure, and the need to improve it, has been a hot political topic for some time, regardless of your party affiliation. When people think about infrastructure, they often think about roads and bridges.

Many times, they may not think about our important hidden infrastructure, namely, piping systems that carry anything from the water we drink, to storm runoff, to communications, to the natural gas we use to cook our meals and heat our homes. 

According to a recent Green Building Solutions blog post, civil engineers estimate 60% of infrastructure repair costs consists of underground piping. We rely on this vast critical “hidden” infrastructure for almost all facets of our lives, and we expect it to work every time. 

What is a quality infrastructure? It’s one that creates a coordinated system of standards, federal and state codes, installation practices, inspection, and advanced products with a focus on safety and long-term performance. 

That dedication to quality has resulted in nearly three million miles (5 million km) of pipelines that deliver nearly 28 Tcf of natural gas per year, according to the U.S Energy Information Administration (EIA). The vast majority of these have performed without incident.

Much of today’s piping infrastructure is made of polyethylene [medium-density polyethylene (MDPE) and high-density polyethylene (HDPE)], polyamide-12 (PA12) and spoolable composite piping. PE pipe has served our infrastructure needs for decades. More and more upgraded or new piping systems are made from plastic pipe, but there is a lot of work to be done. 

As recently as 2017, the Federal Department of Transportation (DOT) estimated 30,000 miles (48,000 km) of cast-iron pipe still carried gas in the United States, with the highest percentage of these mains located in older eastern cities such as New York City, Philadelphia, Boston, Baltimore and Washington, D.C.

Safe, effective, high-quality piping systems are needed for a durable infrastructure. Most polyethylene, polyamide and spoolable composite piping sold for oil and gas applications is manufactured to the highest industry standards, but how can you be sure? 

Not all manufacturers that produce piping systems sold into the United States have the quality systems in place to ensure they meet our industry’s high standards. To ensure a safe system, it is important to look for pipe and components produced to the highest North American standards and specifications and, just as importantly, produced by reputable manufacturers.

In the energy sector, plastic piping is used to bring fresh water to the drilling site, remove produced water from the operation, transport oil and gas, and treat and dispose of wastewater. Highly durable, noncorrosive and leak-free plastic pipe systems used in this state-of-the art process prove to be an invaluable component in protecting the environment. 

In gas distribution, where more than 57% of all piping is PE and more than 98% of the newly installed piping is PE, natural gas is delivered to homes and businesses in a large underground network. 

PE piping has established itself as the “go to” material during many, many years of safe, efficient operation. In fact, PE is such a trusted material that DOT/PHMSA (Pipeline and Hazardous Materials Safety Administration) proposed in its recent Gas Pipeline Regulatory Reform Notice of Proposed Rulemaking (NPRM) that the allowable size of PE be extended to 24 inches (610 mm) from a maximum of 12 inches (305 mm). In addition, DOT/PHMSA recently added PA12 to the list of suitable materials for gas distribution, transmission and gathering for applications all the way up to 250 psig (17 bar). 

It is critical that pipe used in energy infrastructure is properly marked or certified to provide assurance of product quality. A properly marked pipe includes relevant standards on the pipe’s printline to identify piping materials that meet specific standards, and to help confirm that the pipe is suitable for its intended purpose. But this marking alone cannot be relied upon because a printline is no guarantee of the quality of the pipe. 

Pipe manufacturers should participate in the quality systems established in the industry to ensure the pipe performs as expected. This starts with a TR-4 listing in the Plastics Pipe Institute Hydrostatic Stress Board (HSB) Program, which includes the pipe’s recommended Hydrostatic Design Basis (HDB), Strength Design Basis (SDB), Pressure Design Basis (PDB) or Minimum Required Strength (MRS) rating. 

Tests, protocols and methodologies developed by HSB provide the user with confidence that the pipe has the integrity necessary for energy applications. Piping should also meet rigorous standards developed through a consensus process. 

Some of the standards include PE pipe produced and tested to the latest editions of ASTM D2513 for gas distribution, ASTM F2619 and/or API 15LE for oil and gas gathering applications, PA12 pipe produced to ASTM F2785 and spoolable composite piping produced to API 15S. 

Additionally, these standards require that the relevant standard be referenced on the pipe’s printline, so users can readily identify the pipe is suitable for its intended purpose. 

To help educate the industry, Plastics Pipe Institute (PPI) members are developing a model specification (MS) for oil and gas that will aid in the selection of quality HDPE pipe and fittings for oil and gas applications. This new MS includes guidance on qualifying manufacturers, relevant material and joining standards, marking requirements, proper inspection, handling and installation practices, and testing. 

The association also recommends that purchasers review the pipe manufacturer’s certification reports along with physical plant inspections or independent third-party validation. As with all piping materials, not all plastic pipe is created equally. 

Know what resin is being used in the manufacture of the pipe. Know what company is making the pipe. Know what company is selling the pipe. There is a considerable investment for the resin manufacturer and the pipe manufacturer to produce high-performance products. You can rest easier knowing that your manufacturer is a PPI member. 

PPI recommends the following considerations when qualifying a supplier:

     • Demonstrated commitment to the market evidenced by facilities investment and products offered

     • A good reputation for product quality and service based on other user comments; support of the industry through involvement in standards organizations such as ASTM, API and ISO; membership in recognized industry trade associations such as PPI

     •  Adequate in-plant inspection and quality control/quality assurance testing either in the supplier’s own facilities or in a qualified independent laboratory; registration of their quality management systems (QMS) under a recognized quality assurance program such as ISO9001, to ensure proper quality control and quality assurance procedures are in place

     •  Ability to provide sound technical support for its products with on-staff engineering who are knowledgeable on the use and design of selected plastic pipe

We encourage operators to inspect the piping products upon delivery to ensure it meets not only the appropriate product standards but also those within the operator’s specifications. This is especially critical for projects in demanding oil and gas field operations and is important for pipe used in other pressure applications such as water, sewer, industrial and mining.

Unfortunately, due to reduced demand and pricing pressure on energy systems, we are seeing an influx of imported and even some domestic products from unqualified suppliers that do not meet our tough industry standards. 

There is a cost for quality because of the steps required from the manufacturing of the plastic resin to the extrusion of the pipe to produce a product that meets industry standards and regulations. But, the benefits largely outweigh the extra cost. No one wants a pipeline failure caused by substandard pipe, especially in demanding energy applications. 

With fresh and recycled water streaming in at the rate of millions of gallons a day and leaving the area as highly brackish produced water or flowback, the integrity of the pipe and its joints is critical. Most leaks are from corrosion, gaskets and seals within a system.

PE’s and PA12’s monolithic structures basically eliminate the potential for leaks. High-quality piping manufactured to rigorous standards serves the oil and gas industry and will continue to serve the energy industry with biogas, renewables and hydrogen.

 PPI membership is a great way to help identify a high-quality pipe manufacturer. Manufacturers involved in this leading trade association continually strive to raise the bar for the industry. 

These goals are exemplified in two new technical documents recently published by PPI that increase the safety of gas systems by providing standardized industry procedures and best practices for electrofusion of PE piping (PPI TR-49) and butt fusion of PA12 piping (PPI TR-50). PPI continues to lead the industry by providing guidance on the proper manufacturing, application and use of plastic pipes in infrastructure.

PPI and its member companies are ready to assist operators with questions regarding the proper specification and use of HDPE pipe intended for the oil and gas gathering applications. 

Author: David Fink is president of the Plastics Pipe Institute, Inc., the major North American trade association representing the plastic pipe industry. 


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