ECDA For Cased Pipelines

From Pipeline and Gas Journal article "Mears Hosts Workshop On ECDA For Cased Pipelines":

Fifty-six integrity representatives from pipeline and gas utility companies across North America attended the day-long event at Mears headquarters in Rosebush, MI. Speakers included Max Kieba, Central Engineer, Office of Pipeline Safety, who gave directions to attendees on the upcoming PHMSA cased-pipe guidelines. Demonstrations included field indirect and direct inspections of coated and uncoated cased pipe, and a demonstration of wax filling a casing by Royston.

Casings are a common historical practice to prevent overburden stresses and mechanical damage to pipelines, typically at crossings, but they cause some unique problems with cathodic protection and corrosion surveys. Uncased crossings are usually preferable to cased crossings from a corrosion point-of-view. The NACE Standard SP0200 "Steel-Cased Pipeline Practices" (PDF, 833k, free to NACE members $35 for non-members) says:

1.2 Use of cased crossings should be avoided unless required by load considerations, unstable soil conditions, or when their use is dictated by sound engineering practices.

The issue has become critical in the gas transmission industry with the requirements of the Gas IMP rule and the limitations of performing ECDA on cased crossings. There was a PHMSA public meeting in July 2008 to address all the issues of cased crossings. There is more information on the PHMSA meeting website. In particular, this presentation from a liquid operator gives an overall perspective on the issues of casings.

The author also recently participated in an article in the March 2009 Pipeline and Gas Journal titled "Protecting Pipelines At Crossings: Are Casings Obsolete?".

Also, see previous post on the Pipeline Cased Crossings Casing Quality Action Team (CASQAT) here.