Kiefner and Associates, Inc., an Applus+ Company, in collaboration with the Illinois Commerce Commission, recently completed a complex project to evaluate the replacement speed and remaining life of the complete cast iron and ductile iron pipeline system supplying much of the City of Chicago. This project represented the first known empirical evaluation of a system of this kind.
Cast Iron and Ductile Iron materials were used to fabricate pipeline systems during the latter half of the 19th century and in the first half of the 20th century. Many of the pipes evaluated by Kiefner over the course of this project predated the Great Chicago fire. Unfortunately, cast iron and ductile iron are brittle materials. Because of this, the methods used to manufacture the pipes resulted in varying wall thicknesses. Cast Iron is also subject to graphitic corrosion, among other issues. As a result of these shortcomings, the Pipeline and Hazardous Materials Safety Administration (PHMSA) recognizes that cast iron and ductile iron pipes are among the highest risk pipes in the ground. A “Call to Action” was issued to federal, state, and local regulators to consider utility programs for the accelerated replacement of these materials.
Remaining life estimation of cast iron pipes is a complex problem with little prior literature available. This project afforded Kiefner the opportunity to apply the latest advancements in data analytics, structural analysis, and risk management to evaluate the remaining life of the iron pipes. The engineering-based study consisted of three parallel assessments: Corrosion, Structural Analysis, and Risk. The final report demonstrating Kiefner’s capabilities can be downloaded from the Illinois Commerce Commission’s website.
The successful completion of this project resulted in Kiefner’s development of a method for creating risk models for cast and ductile iron pipe systems. Kiefner’s models and methodologies can now be applied to other willing utility companies facing similar challenges. This work contributes to Kiefner’s overarching objective of ensuring public safety and welfare through shared knowledge and non-confidential information.