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 […]
A rather common issue these days is decision making involving comparisons between In Line Inspection (ILI) vs Direct Assessment (DA, and, in particular, External Corrosion DA or ECDA). You may need to research these techniques, if not already familiar to you, since we will assume the reader is fairly familiar with both. Both are acceptable […]
This recommended pipeline risk assessment methodology is similar to SRA (Structural Reliability Analyses) and LSD (Limit State Design) or LRFD (Load and Resistance Factor Design). This is coincidental, since the methodology was developed independently from these techniques. However, despite the similarities, there are key differences. Similarities include: Focus on engineering principles rather than incident history Accommodates […]
Generally, a pipeline’s reliability includes consideration of all leak/rupture scenarios PLUS all other scenarios that could prevent the system from performing its intended function. With the normal ‘intended function’ being something like: deliver product to point B from point A at specified flow rates, pressures, temperatures, and product quality, a reliability failure occurs when any […]
As we continue this exploration of pipeline risk assessment, let’s tackle some terminology obstacles. Pipeline risk assessment is a challenging topic on its own, so added confusion from terminology is most unwelcome. Background In some recent regulatory initiatives, a criticism has arisen regarding some pipeline operators’ failure to properly account for ‘threat interaction’ in their […]
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, […]
As the desire for more robust pipeline risk management grows, so too does the need for superior risk assessment. A formal risk assessment provides the structure to increase understanding, reduce subjectivity, and ensure that important considerations are not overlooked. Associated decision-making is therefore more consistent and reliable when formal techniques are used. But has pipeline […]
True. You can put in non-linear equations as part of the TTF estimate. A risk assessment should represent the actual underlying science as much as possible/practical.
This is one of the more challenging aspects of modern risk assessment. One of the keys is to select the future date for which the PoF is being estimated. This is often ‘next year’ but can really be 5 years, 10 years, 20 years, etc into the future. Another key is to ensure that both likely and […]
TTF is indeed the more useful metric for many applications. However, you also need to get a PoF from each time-dependent failure mechanism in order to compare them with other threats and get an overall PoF.