Pennsylvania regulators Thursday approved Columbia Gas of Pennsylvania’s plan to repair and replace its existing gas distribution system, portions of which are 100 to 200 years old and vulnerable to cracking and leaking.

The local distribution company (LDC) determined that there are an increasing number of leaks in areas on its system with a high concentration of aging pipe. Some portions of its system date back to the 1800s, when cast iron was considered to be relatively strong and easy to install.

However, it was later learned that cast iron was vulnerable to breakage from ground movement. The industry transitioned to bare steel and wrought iron piping by the early 1900s, which was popular until the 1960s, when it was determined that bare steel was subject to corrosion. Next, the industry moved to plastic piping in the 1970s, but it was found to be vulnerable to stress propagation cracking.

Over the next five years, Columbia Gas of Pennsylvania said it expects to replace approximately 2.8 million feet of cast iron and bare steel main on its system. In addition to the mains, the utility anticipates that it will replace 7,000 to 9,000 service lines per year over the next five years for 36,000 service lines by the end of 2017. The utility is planning to replace its distribution lines with cathodically protected steel, which has all the advantages of steel, is highly corrosion-resistant and can handle higher distribution pressures, said Denis McCracken, a spokeswoman for the Pennsylvania Public Utility Commission.

The gas utility said the replacement of all the cast iron and bare steel main on its system will be completed in about 17 years, or by the end of 2029.

Columbia’s accelerated pipe replacement is in response to a new drive by the federal Pipeline and Hazardous Safety Administration to work with state safety programs and pipeline operators to speed up identification, repair, rehabilitation, requalification or replacement of the highest-risk pipelines. Following several pipeline accidents in the last few years, the agency said it would extend the pipeline integrity management program to gas distribution pipeline systems, where 80% of the most serious safety incidents occur; and investigate new technologies to improve the assessment, detection and control of pipeline risks (see Daily GPI, Sept. 14, 2012).

In addition, the LDC said it plans to install or replace excess flow valves, regulators and risers and meter bars along with the service line replacements. It estimates it will spend an annual amount of $131.48 million on infrastructure replacement between 2013 and 2017, up significantly from the $78.3 million that it spent during the previous five years.

Columbia said it has been identifying and repairing or replacing its distribution infrastructure on an accelerated basis since 2007. The utility said corrosion on first generation mains and services represents more than 85% of all the leakage that occurs on mains on its system. Bare steel and cast iron mains are at least 16 times more likely to experience leakage than plastic or cathodically protected facilities, according to the LDC.

It estimated it invested more than $400 million in 2007 to replace approximately 2.59 million feet of pipe. Since 2006 the utility said it has replaced or retired 17.3% of the total amount of cast iron and unprotected bare steel that existed on its system five years ago. In 2011 alone, Columbia estimated it spend approximately $92 million and replaced 533,765 feet of bare steel and cast iron pipe. Another 510,000 feet was replaced last year. As a result, the company said it has reduced Class 2 leaks on its system by nearly 50% since 2007.

Columbia will be able to recover the upgrade costs as “reasonable and prudent costs” to repair, improve or replace certain eligible distribution property. Columbia Gas of Pennsylvania provides gas service to approximately 415,000 customers in 26 counties in western and south central Pennsylvania.

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