View stunning SlideShares in full-screen with the new iOS app!Introducing SlideShare for AndroidExplore all your favorite topics in the SlideShare appGet the SlideShare app to Save for Later — even offline
View stunning SlideShares in full-screen with the new Android app!View stunning SlideShares in full-screen with the new iOS app!
PIPELINE INTEGRITY California Contract Cities Association First Responders. Overview of inline inspection operations
Bellingham Washington On June 10, 1999 an Olympic Pipe Line Company pipeline ruptured and spilled over 236,000 gallons of gasoline into Hanna and Whatcom Creeks. The resulting explosion consisted of a fireball which raced one and one-half miles down Whatcom Creek and created a smoke plume twenty to thirty thousand feet high. Three people were killed - two ten-year old boys and an 18-year old young man who was fishing in Whatcom Creek. Eight people were injured and extensive damage incurred over the mile and one-half length of Whatcom Creek.
Carlsbad New Mexico On August 19, 2000. A transmission pipeline ruptured and a fire killed 12 campers near Carlsbad, New Mexico. Federal investigators determined that the cause was severe internal corrosion of transmission pipeline; over 70% of the wall had been eaten away near the rupture site . Just Pig-it
HCA identifies Class locations where there are facilities with persons who are mobility-impaired, confined, or hard to evacuate, and places where people gather for recreational and other purposes (20 or more for 50 or more days per year).
The corridor of protection from the pipeline is 300 feet, 660 feet or 1000 feet depending on the pipeline's diameter and operating pressure.
Direct assessment consists of direct examinations at pre-determined locations on a pipeline where potential external corrosion might exist.
The direct examination locations are chosen on the basis of indirect inspection surveys or by modeling. Direct assessment would usually be used only if in-line inspection or hydrostatic testing are not feasible options.
Hydrostatic testing has the major disadvantage of requiring that a pipeline must be out of service for extended periods of time, and it is considered a destructive test, since location of a defect requires that the pipeline experience a leak or rupture during testing. Disposal of hydrostatic test water can also be difficult and expensive due to environmental considerations.
The “Indirect Inspection” step uses a combination of 2 or more above ground survey techniques such as close interval potential survey (CIPS), alternating current voltage gradient (ACVG), direct current voltage gradient (DCVG), AC attenuation for the identification of areas with corrosion activities or coating faults. The data is evaluated via systematic analysis and high-risk areas are identified for excavation.
Magnetic flux leakage (MFL) is a magnetic method of nondestructive testing that is used to detect corrosion and pitting in steel structures, most commonly pipelines and storage tanks. The basic principle is that a powerful magnet is used to magnetize the steel. At areas where there is corrosion or missing metal, the magnetic field "leaks" from the steel. In an MFL tool, a magnetic detector is placed between the poles of the magnet to detect the leakage field. Analysts interpret the chart recording of the leakage field to identify damaged areas and hopefully to estimate the depth of metal loss. PIPELINE INTEGRITY MFL PIGS
MFL can detect corrosion by sensing magnetic leakage. First, it initiates a magnetic field in the pipeline. If there are any flaws in the pipeline wall, some of the magnetic field will escape. Sensors onboard the pigs detect and measure that leakage. Smart pigs equipped with MFL technology can determine whether the corrosion is internal or external, and they can also measure for changes in the thickness of the walls. PIPELINE INTEGRITY MFL PIGS
A 28-foot segment of ruptured pipe shows signs that its steel had become brittle over the decades. The blast point also occurred at a dip in the landscape that left the underground pipe subject to corrosion from accumulating water and sewage. And that bend in the line meant more welds were used during construction, creating another potential vulnerability