Ironing Out the Facts

The United States has come face-to-face with a critical infrastructure crisis, not one that is years away, rather one that is here and now.

According to a recent report by the American Water Works Association (AWWA), the United States must invest $1 trillion in underground water infrastructure work over the next 25 years. If the country delays this work, failures will increase in frequency and the costs of repair and/or replacement will only go up. The public will have to pay a far steeper price in terms of reliability, threats to public health and safety and ultimately, in taxes and rates.

It is a monumental challenge, one that must be approached wisely, weighing both short-term and long-term costs and environmental and fiscal ramifications. It demands a commitment by our leaders to think big, to move quickly and to do what?s right in the right way.

Most older water systems in place today were made of cast iron, which has lasted far longer and done much more than ever contemplated. One reason national water infrastructure investments have been delayed for so long is precisely because iron pipe has lasted longer than anyone ever imagined. Today, utilities use modern ductile iron to build durable, reliable, efficient and environmentally ? sound water infrastructure systems ? and ductile iron is far stronger than its predecessor, cast iron. With modern metallurgy and engineering, ductile iron pipelines are designed to provide a minimum of 100 years of reliable service.

This recognition of past service and future realities is important to remember in light of alternative choices that have been introduced in the last 100 years while iron pipe has been in service.

A Commitment to Sustainability

With so many claiming to have ?green? products, it is difficult to determine which are environmentally sound and which are simply ?greenwashing? the truth. Fortunately, there are several groups and projects working to establish clear guidelines for transparency in building and infrastructure materials, including LEED certification, a rating system related to the sustainability of buildings and neighborhoods; the Pharos Project, a tool to assess the health and environmental impacts of a product throughout its life cycle; and the independent SMaRT certification, a rating system for the sustainability of a product throughout its life cycle.

The ductile iron pipe industry is committed to creating a sustainable product by managing resources, educating users and designers, being transparent and ensuring safety and health in the workplace. The member companies of Ductile Iron Pipe Research Association (DIPRA) are leading the effort, working to establish environmental, health and safety requirements for their products. Recently, ductile iron pipe received its SMaRT certification as a sustainable product, making it the clear choice for sustainable infrastructure investments. This certification results in the eligibility of ductile iron pipe for as many as three LEED credits.

In addition to its durability and reliability, ductile iron pipe?s sustainable attributes begin with the fact that ductile iron pipe is made from recycled scrap materials such as junked automobiles and is, in turn, completely recyclable.

It is also the smart choice financially because it requires few repairs and less operation and maintenance costs. Ductile iron pipe can be direct-tapped and cut to length in the field. Its joints are flexible, allowing standard fittings sizes and the ability to route pipe along smooth curves minimizing the need for fittings. Other pipe materials, such as PVC, require tapping saddles and must be bent to route without fittings, or rely more on side-fill soil support. This select backfill ? typically compacted crushed stone or sand bedding ? often has to be imported, making installation more costly and increasing transportation costs.

And let?s not forget energy costs. The EPA reports that energy costs can make up to 30 percent of a water utility?s total operation and maintenance expenses. With water bills increasing, utilities need to consider not only the initial costs of installing pipe and the long-range repair and maintenance costs, but also the long-term pumping costs.

With ductile iron pipe, the long-term savings are significant. Because of its strength, properly designed ductile iron pipe will typically have larger than nominal inside diameters. Therefore, pumping water through ductile iron pipe can offer as much as 38 percent savings in energy consumption over PVC, according to studies by DIPRA. The same is true when comparing other materials with ductile iron ? as all have typically higher pumping costs than iron pipe. Pumping water through HDPE pipe can be up to 160 percent more costly than pumping through iron. So, while plastic pipe materials may tout their smooth walls, in reality, all major pipe materials have similarly smooth flow surfaces. The predominant factor in energy used in pumping is the actual inside diameter of the pipe. Therefore, using ductile iron pipe can lower water bills, help consumers save electricity and reduce our carbon footprint all at once.

Despite all of these considerations, some competitors claim that their products are cheaper than ductile iron. However, when one thinks about systems as important as those that bring safe drinking water to our communities, value ? not initial cost ? should be the watchword, and value encompasses factors such as pipe failures and disruption of service.

Competitors also claim that iron pipe is vulnerable to corrosion, but the fact is that much of the iron pipe in service today has been in the ground for more than a century, and the majority of older cast iron pipe was installed long before corrosion control was a part of engineering design. Utility engineers have long protected ductile iron pipe with polyethylene encasement, an effective engineered system of corrosion control since 1958. First used experimentally in 1951 in the most challenging environments, it is now used successfully throughout the country to economically and effectively protect hundreds of millions of feet of modern ductile iron pipe.

Durability and Corrosion Control

Iron pipe has proven strong and reliable for nearly 200 years in water and wastewater systems across North America and for nearly 350 years in Europe. The ductile iron pipe industry continues to deliver outstanding service while constantly exploring innovative ways to improve its product, especially with regard to corrosion control.

While the PVC pipe industry claims iron pipe corrodes on the inside, problems associated with internal corrosion were alleviated decades ago with the popular (and now standard) use of cement-mortar linings.

The ductile iron pipe industry has long focused on preventing corrosion from aggressive soils. In recent years, DIPRA has partnered with Corrpro Companies, Inc. to develop the Design Decision Model, a system that balances the likelihood of corrosion along a proposed pipeline route against the consequences of a potential corrosion-related problem. Based on this evaluation, the model recommends the best method to prevent corrosion and extend the pipe?s life. These recommendations include installing the pipe in its as-manufactured condition in benign environments, encasing the pipe in polyethylene and providing cathodic protection. When protected correctly, modern ductile iron pipe has a minimum service life of 100 years.

To assess the effectiveness of corrosion control in the most corrosive soils, DIPRA routinely inspects pipe that was installed with polyethylene encasement. One such investigation recently took place in Lafourche Parish, La. ? the first known polyethylene encasement installation. When the gray cast iron pipe was excavated, it was evident that superficial oxidization had occurred. However, as the pipe was cleaned and further inspected, it was found to be sound and free of any pitting or graphitization. After 50 years of service, the polyethylene encasement continued to protect the pipe.

Several similar investigations demonstrated that properly installed polyethylene encasement can effectively and economically protect iron pipe from most corrosive soil environments. DIPRA is constantly testing new enhancements to improve the performance of an already proven system. These measures ensure many decades of service from durable and reliable ductile iron pipe. ?

The Smart Investment

All of these factors lead to only one conclusion: the economic, operational, health and environmental facts in support of ductile iron pipe are clear. Having been independently certified as a sustainable product, ductile iron pipe is leading the way on the environmental front, making it the right choice for a long-term, sustainable investment. As utility boards and other decision-makers choose one material over another, they will do so knowing that the strongest, most reliable pipe product is also the least expensive alternative.

The ductile iron pipe industry is at the forefront of modern design, metallurgy and sustainability in water and wastewater pipelines. As a result, the older cast iron pipelines that gave us a century of service without the benefit of today?s technologies can be replaced with modern ductile iron pipelines that can provide better service by design. Ductile iron pipe is the smarter, safer investment.

Gregg Horn is president of the Ductile Iron Pipe Research Association (DIPRA).

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