Performing a Condition Assessment of a 24-inch Diameter Gas Line Supplying an Important Part of a Suburban Area of a Large Midwest City

摘要

This paper discusses the inspection tools, procedures and field operations performed in 2011 for the in line condition assessment of a 30 year old, 13 mile long, 24 inch diameter gas transmission line, operating between 250 and 300 psi, that had not been inspected after being placed in operation. Since the line supplies an important part of a suburban area of a large Midwest city with natural gas for domestic, commercial and industrial consumption, the assessment was important to determine whether the line conditions were adequate for continuing operational safety. Additionally the assessment would serve as a comparative baseline for future assessments while the associated cleaning would help improve line flow. Project challenges included limited work areas, public activities adjacent to the tool launching site; load restrictions; limited access to the transmission line easement and right of way, that traversed both residential and environmentally sensitive areas; and commercial and light industry activities close to the gas venting lines at the launching and receiving site.