By Chris Paul
A Department of Transportation report titled The State of the National
Pipeline Infrastructure: A Preliminary Report said that of the 2.5 million
miles of pipeline nationwide, only a small, unspecified percentage is
unfit for service because of the material the pipeline was made of and the
way it was joined and installed. The Pipeline and Hazardous Materials
Safety Administration (PHMSA) reported that “just because one pipeline
is older than another does not necessarily mean that it has a higher
likelihood of leaking or rupturing.” Instead, the agency said that pipelines
that are most vulnerable are those made of problematic materials using
outdated construction practices. DOT said that smaller cast iron pipes are
particularly susceptible to stresses from underground disturbances such as
ground settlement, freeze-thaw cycles, undermining due to soil erosion or
nearby excavation activities, and that copper service lines installed during
the 1970s have been found to be most vulnerable to corrosion. PHMSA
pointed out that pipes built using certain out-of-favor welding techniques
have been problematic as well.,