PPIM
Tools for a Modern IM Program
Abstract:
Just doing the bare minimum necessary for compliance is no longer an acceptable strategy for an integrity management program today. With the additional requirements added by the rules published in 2019, it is imperative to develop and maintain appropriate processes and methodologies. Doing the minimum will always put the operator in the situation of being reactive and never getting ahead of the work. The intent of an integrity management program is not to simply find and fix issues.
This paper will outline several techniques to help move an integrity program from reactive to predictive and allow for better planning for threat mitigation.
Pipeline owner operators sometimes forget that regulations are minimum requirements. They often do not prompt the actions that rise to the level of prudent asset stewardship in some instances.
There is also the issue of compliance with these minimum regulatory requirements. Sometimes an operator takes confidence in the fact that they have ” survived” an audit. Most audits are spot checks. They are not intended to do the kind of rigorous confirmation all minimum requirements are being met. Contrast that with a pipeline accident or incident where many parties will be examining in great detail every action the owner operator has taken.
So, we have two issues here. One is that actions beyond minimum regulations are often required and two, it’s not always certain if even the minimum requirements are being met. Let’s look at integrity management regulations in particular with regard to these two aspects.
Integrity management IMP is an example of more detailed, advanced regulations. The intent of an IMP is not to simply find and fix issues. PHMSA has voiced an expectation That a compliant IMP program is a robust and comprehensive way to manage pipeline integrity.
Some of the required elements of IMP that are often underperforming include
- QRA
- PMM decision-basis
- Leak detection capability analyses, with decision-bases
- EFRD
- Threat dismissal (many think they can use ECDA as only assessment without justifying it)
- TTF based on largest remaining defect and mpy estimates
- Fatigue as a threat
- ECA (Engineering Critical Analysis)
The reason that these are often underperforming is because they can be very technically challenging. The good news however is that there are approximate and screening- type solutions that can give credible and conservative answers to these issues without a lot of technical rigor. Even better news is the fact that when even an approximate solution is employed the need for actions beyond minimum regulatory compliance are often revealed.
Let’s demystify these common gaps. The intent here is to examine options in level of rigor that can both address these gaps in minimum compliance and also point to where actions beyond regulatory minimums are warranted.
Quantitative risk assessment QRA is the recommended way to measure risks–recommended by regulators and the scientific community. It has many advantages over any competing technique, including (surprisingly to some) the fact that its actually cheaper to implement and maintain. QRA can be performed without an extraordinary amount of data and without advanced statistical analysis. The myth that QRA requires reams of data has been dispelled. Armed with good risk measurements the operator is now in a position to decide when and where additional measures (beyond regulatory minimums) is appropriate. He is also now in a position to set corporate risk strategies.
P&M decision making can be defensibly and efficiently conducted using cost benefit analysis– the most widely accepted risk management strategy worldwide. While cost benefit may seem cold and calculating to some, it is actually the most fair, consistent, and defensible way to make decisions even when public safety is one of the issues. QRA results drive the cost-benefit analyses.
Fatigue cracking is not a dominant threat for most pipelines. However, it should be examined as a potential threat for every pipeline. But rather than doing finite element analysis on thousands of components and analyzing gigabytes of SCADA pressure data every year, a simple screening analysis may make this threat immediately dismissible for some pipeline systems. If the most vulnerable specification is exposed to the most rigorous cycling regime and there is still no threat of fatigue, then it can be safely concluded that no other portion of the system is vulnerable.
EFRD and leak detection capability analysis are simply examinations of mitigation measures. As such they can be dealt with efficiently just as any other P&M decision making. A cost benefit screening analysis can determine if and where additional valves or additional leak detection capabilities are warranted. Again, the risk assessment leads the way here.
As with other potential mitigation measures, when a cost benefit analysis is properly done, it points to the most efficient use of resources. This efficiency benefits the public as well as the operator. It is to no one’s advantage to spend our limited resources inefficiently.
When an operator chooses to use a direct assessment type (ECDA, ICDA, SCCDA) technique as the sole method of integrity assessment he must make sure that other threats are not plausible. This does not necessarily have to be a detailed technical evaluation. A structured and logical examination of the characteristics of the operation can often, with a reasonable degree of certainty, dismiss the potential for, for example AC induced corrosion, internal corrosion, fatigue cracking , and others. But without at least a high-level screening type basis for dismissing these threats, a single DA cannot be the sole determinant of integrity.
A time to failure estimate (TTF) is required as part of the determination of integrity reassessment intervals. An estimate of TTF is required even when the operator is using the maximum allowable intervals. The estimation of TTF requires 2 ingredients. 1st what is the largest remaining defect after the most recent integrity assessment. Each integrity assessment technique has advantages and disadvantages and each has a chance of missing certain types of defects. The 2nd ingredient required is the possible future degradation rate of that defect. Both of these values should be clearly stated in an operators IMP. Levels of conservatism and assumptions employed should be included in these documented values. Again, this issue can be addressed with varying levels of rigor. Conservative defaults are available when needed. But at a minimum, an operator should choose conservative and defensible values and document those.
While the approximate yet conservative solutions can play a role in IMP, let’s not lose sight of the fact that oftentimes a more rigorous, robust analysis will still be required. That is not necessarily a bad thing. A rigorous analysis often pays for itself when the alternatives, based on approximate analyses, are unnecessarily expensive.
When additional rigor is warranted, we can bring in tools such as inferential statistical analysis, pattern recognition, quantification of uncertainty, advanced fracture mechanics, and others.