September 7, 2006 | Ken Reed


More data has been released concerning the Alaskan oil pipeline leak that shut down a major portion of the Prudhoe Bay oil field on the Alaskan North Slope. It appears that BP changed their pipeline PM requirements based on the history of failures, then did not check to see if this new schedule was working correctly. After years of running a pig through the pipeline at fairly close intervals to clean the pipes, they decided to stop the cleaning and only conduct spot ultrasonic testing of the piping instead. Another pig inspection and cleaning was slated for next year (9 year interval), but leaks were found last month that required the shutdown. The company now plans to replace 16 miles of deficient piping.

Anytime a major change is made to a PM schedule, many risks must be considered. In hindsight, it may be easy to say that BP poorly anticipated the consequences of their change in maintenance strategy, but how do you mitigate these possible consequences?

It would be nice to know what the possible modes of failure are when changing (or initially developing) a maintenance plan. Once these failure modes are known, you can tailor your preventive maintenance to target the most likely (or catestrophic) failures.

Equifactor® to the rescue! When you initially install a new piece of gear, why not take a look at Equifactor® to determine how your machine might fail? Set up your PM schedules to target these failure modes, and get rid of those PM’s that are not relevant to your piece of gear. This will allow you to funnel your maintenance dollars toward the areas actually needing the maintenance. Consider Equifactor® to be an important tool in your RCM toolbox.

Another consideration for developing (or changing) your maintenance strategy is the possible consequences of a failure. Drastic changes in a critical system may not be advisable. Smaller changes, or additional checks, might need to be instituted to catch costly failures resulting from changes to the maintenance plan.

Root Cause Analysis
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