When performing a failure analysis, the first thing is to do an overall analysis in order to get a general feel for what caused the failure. Once you begin, you look for an origin and determine where the origin is. With the origin you can then figure out what the cause of the failure is, and once you have the cause of the failure then you can determine where to go from there.
Once you have the cause and have addressed the specific cause of the failure, you look at how that failure fits in to the rest of the pipeline. If the pipeline is 100 miles long, is this particular damage possible another location? Maybe there is corrosion at another location. Maybe there is construction at another location. Is there potential for damage at another location? So you can take an individual rupture or failure and determine how likely it is to have another cause. That’s when you want to perform an analysis where we can develop the integrity management program in order to address other issues.
This type of analyses can take a lot of forms. They can take the form of destructive testing to figure out what the potential for failure is, given a certain size of flaw. You can determine the factors that go in to causing that failure and then look for the same factors along the pipeline in order to do an integrity assessment. Once you have that, you can develop a program to try to minimize risk in the future by predicting places in the line where those things could happen again and eliminating those possibilities. You can also help the operator develop a repair methodology. How do they repair the pipeline? You understand why it failed, and now you can go in and develop a remediation program in order to reduce the possibility of failures in the future.
As previously mentioned, the first thing you have to understand is the origin and experience tells you how to find an origin. Once you find the origin you need to look at why the origin is so important. Experience offers you the opportunity to sort out all of those different variables in order to figure out how to determine the cause of the failure. Experience also tells you where to look for those problems along the pipeline in the future when you are doing the integrity management program or the assessment. Having experience tells you where to look for those problems again.
Vintage pipelines are essentially defined as something that’s older than about 50 years. Vintage pipelines were constructed using different construction processes, different practices, and those practices induce certain kinds of systemic problems in pipelines. So if you understand how the pipeline is manufactured, how the pipeline is constructed, then you know what to look for. The same thing is apparent when the pipe is manufactured – they manufacture the pipe using a lot of different techniques. There are different welding techniques used in the long seam weld, and some of those welding techniques are better than others. The ones that are of poor quality, if you see those in the pipeline, you know that’s a potential problem and you need to look for those problems at other locations along the pipeline. Understanding how the vintage pipeline is manufactured gives you an idea where to look for those problems and how to remediate those problems. Understanding how they are made and where the problems are gives you an understanding of what need to do to fix those problems or make them safe for the future. So understanding all of those variables is very important in doing a failure analysis and in addressing the integrity threat.