Measuring the Effectiveness of the U.S. IMP Program

Abstract

The requirement to perform Integrity Management Programs (IMP) in the U.S. was mandated by Congress at the end of 2002. Actual inspections began in 2004. The Interstate Natural Gas Association of America, (INGAA), began a program to measure the effectiveness of the IMP (Integrity Management Program) with some of its member companies, representing approximately 120,000 miles of transmission pipeline. The U.S. has 295,000miles of on shore gas transmission piping. This paper provides 6 years of gathered data on IMP activities and compares them to PHMSA data. The INGAA participating companies have inspected more than 80% of their High Consequence Areas (HCAs) while the total for all PHMSA miles is more than 90% by the end of 2009. The number of PHMSA reported immediate and scheduled repairs being made in HCAs is 0.17 repairs/mile of assessed HCA averaged over the 6 year period. The total number of all repairs reported for the INGAA companies is an average of 0.11 repairs per mile of HCA inspected. There were 6 reportable incidents in HCAs in 2009 for all onshore gas transmission piping, 5 of which were due to third party caused damage. Reassessments, re-inspection of pipe that already had a baseline inspection, are reported for the INGAA program. For calendar years 2007 through 2009, a total of 641 HCA miles of pipeline have been reassessed. There were 19 repairs made in the reassessed pipe, equating to 0.03 repairs/mile, a 73% reduction in the number of repairs in reassessed pipeline.