Risk assessment on any facility is most efficiently done by first dividing the facility into components with unchanging risk characteristics. For a cross-country pipeline, this involves collecting data on all portions of the pipeline and its surroundings and then using this data to ‘dynamically segment’ the pipeline into segments of varying length. Risk algorithms are […]
Topic: Risk Assessment
The Test of Time Estimation of Exposure
In the absence of more compelling evidence, an appropriate starting point for the exposure estimation may be the fact that a component or collection of components has not failed after x years in service. This involves the notion of having ‘withstood the test of time’. A component having survived a threat, especially for many years, […]
Damage vs failure: a risk assessment needs to know the difference
To measure resistance in a way most useful to a risk assessment, we must estimate the possible presence of weaknesses, the rate of emergence of future weaknesses, and the role of each weakness in strength reduction. By W. Kent Muhlbauer, WKM Consulting, Austin, TX, USA Since several of our recent columns have dealt with management-of-risk […]
Measuring Failure Potential—What is Attacking?
How Effective are Defenses? Can it Survive? In several previous columns, we have noted the need for a very specific approach to measuring failure probability (PoF). Three factors must be independently measured/estimated in order to fully understand PoF. Let’s explore those factors a bit deeper here. Regardless of the definition of ‘failure’ being used, failure […]
Myth Busting—I don’t have enough data (Part 2)
In the first part of this discussion, we hopefully dispelled some myths about low data availability. We discussed how reasoning is used to generate data and how many useful pieces of risk insight emerge from even simple pieces of knowledge. We also contrasted a statistical approach to risk assessment with a physics based approach. The […]
Pipeline Risk Assessment—A Measurement Tool
Last time, we introduced the concept of essential elements for pipeline risk assessment. These are the “let’s all get on the same page” aspects that every risk assessment should have in common. An important Essential Element calls for the use of measurements instead of any other kind of rating scheme (eg, indexes, points, scores, descriptors, […]
The PHMSA has recently criticised how Integrity Management Plan (IMP) risk assessments (RAs) for pipelines are being conducted. Do you also see problems?
There is a wide range of practice among pipeline operators right now. Some RA is admittedly in need of improvement, not yet meeting the intent of the IMP regulation. However, I believe that is not due to lack of good intention, but rather incomplete understanding of risk. Risk is a relatively new concept, and is […]
Calibration of Risk Estimates
Resources to help validate, verify, and calibrate risk assessment results: Book chapter 3.7 phmsa pipeline failure investigation reports USA pipeline incident stats European pipeline accident stats Canadian Australian UK pipeline regulation, guidance, data
Consequence of Failure Estimations
Resources to assist in understanding and assessing potential hazard zones and associated damages from pipeline failures: PHMSA leak study (pdf file) PHMSA valve study PIR natural gas (pdf file) PIR other products Potential Impact Radius Final Report June 2005 (pdf file) Study of pipelines that ruptured at stress below 30pct SMYS PPIM 2013 (pdf file) […]
Resistance Estimations
Resources to help identify how much resistance each pipeline component has to each force that threatens its integrity: possible weaknesses (pdf file) vintage pipe possible weaknesses (pdf file) dent study (pdf file) wrinkle study (pdf file) pressure testing Spike Hydrostatic Test Evaluation Final Report July2004 (pdf file) Kiefner Publications ILI