*As seen in Inspectioneering Journal’s January/February 2020 issue.
Last November, Inspectioneering and Pinnacle co-hosted their 5th bi-annual ‘Meeting of the Minds’ (MOTM) roundtable discussion in Atlanta, Georgia. The meeting, in which a select group of leading mechanical integrity (MI) experts gathered over dinner, explored numerous issues affecting our industry. Something to remember is the participants come from various sectors of the industry, including Refining/Petrochemicals, Offshore Production, and Chemical Processing.
You may recall from previous MOTM Recaps that these discussions have covered topics like corrosion under insulation (CUI) programs, integrity operating windows (IOWs), corrosion control documents (CCDs), internal site assessments, risk-based inspection (RBI), and addressing the “Great Crew Change.” This meeting’s focus was on notable technologies that have been tested and/or adopted at the participants’ facilities and how they are changing the MI landscape. Below is a quick recap of some of the key takeaways.
Unmanned Aerial Vehicles
The Fall 2019 discussion kicked off with several of the participants discussing their experience with unmanned aerial vehicles, commonly referred to as drones. All participants agreed that drones and automated crawlers have demonstrated immense utility when it comes to accessing and inspecting various types of equipment at their facilities. The participants reiterated, however, that drones should not take the place of a thorough inspection or capable inspectors, but rather, can help supplement inspection activities with useful information (e.g., help identify areas requiring attention).
Some of the successful use cases included visual inspections of flare stacks, structural steel, offshore rigs, and even the inside of tanks and coke drums. As the quality of onboard cameras continues to improve, high definition images and video are providing MI departments with excellent information to supplement their inspection and maintenance programs. Plus, they are completing these inspections much quicker, without having to put personnel in higher risk environments, saving facilities both time and money.
There was also a brief discussion on some additional inspection capabilities of drones. Some participants have had success using drones outfitted with thermal scanning/infrared technology for inspecting refractory-lined equipment (e.g., furnaces) for hot spots. Several participants said they were aware of some companies outfitting drones with Ultrasonic Testing and Pulsed Eddy Current technologies, but they had not tested it at their facilities.
It was apparent though that there are still many challenges to overcome in order to see widespread drone adoption. One participant stated that he sees a lot of parallels between the early adoption of rope access and drones. Companies were initially resistant to using rope access in place of traditional scaffolding for various inspection and maintenance activities, but now it’s commonplace and rope access is widely considered one of the safest and most cost-effective methods available today.
The participants agreed that one issue is that there has yet to be any clear, standardized guidance on how drones should be used/managed to ensure that no laws are broken and the owner/operators are not exposing themselves to further risk. While some are using drones at their facilities, others said they are restricted from using them around operating units. One participant from the refining sector said that his company has created internal drone operating procedures/requirements that detail things like:
- Drone size requirements
- Mandated collision avoidance technology
- Where operators can and cannot fly
- Rules about keeping a line-of-sight at all times
- Operating Checklists
Looking ahead, the general consensus was that this technology will continue to improve and see increased adoption as owner/operators better understand the capabilities. One specific application the group was excited about was using drones to fly predetermined flight paths around a facility, similar to operator rounds. One participant said that in the near future, he expects “drones will be used to fly 360 degrees around a unit, capture high-definition images of the entire unit, and artificial intelligence will then identify changes that could present potential problems (e.g., external corrosion, a bolt loosening up, unwanted dripping, etc.).”
Laser Scanning/3D Imaging Coupled with AI
Speaking of artificial intelligence, one of the attendees from the upstream sector recently deployed a new initiative to combat external corrosion on offshore platforms. They are taking laser scans of their facilities and using machine learning to process and analyze each pixel of each hi-definition image individually. Furthermore, they’ve developed an algorithm that can determine the severity of any visible external corrosion based on the pixel color.
Along with the laser scan, they have integrated their P&IDs and pipe specs into a 3D model with an XYZ location for each pixel, so each pixel can be graded on corrosion severity and tied back to the line number. The grading system goes from severe corrosion all the way down to moderate and light corrosion. One can then generate a prioritized line list that, for example, identifies severe corrosion on 40 high-pressure gas lines that one can then go inspect or replace as necessary.
In addition, with the accuracy of the laser scan, supplemented by the P&IDs and pipe specs, once that line is identified and proofed up in the model, one can then click on the line and see a fabrication ISO with a full build of materials. One can also assign corrosion circuits for your systems and overlay that with the 3D model to easily see all inspection ISOs for a given circuit.
Moreover, with the P&ID integration, the program can call out discrepancies between what’s in the field scans and what’s in the P&IDs and provide a list with images. From a process safety perspective, this can be helpful identifying things like a missing valve where a P&ID says one should exist.
This program is still in its infancy, but based on the reactions around the room, it could prove to be an incredibly powerful tool for MI professionals across the industry.
Advanced NDE Technologies
During the course of our 2 ½ hour discussion, there were several NDE technologies brought up that are being tested and/or utilized by the participants for specific issues at their facilities.
Positive Material Identification
For positive material identification (PMI), we briefly discussed laser-induced breakdown spectroscopy, or LIBS, and its utility as a handheld tool for identifying carbon content in metal. The room was noticeably skeptical and in agreement that the outside environment makes it incredibly difficult to consistently get accurate readings.
One participant described a study he had done with disappointing results. In his example, he took field tests with a handheld LIBS device and compared it to a sample taken in for lab tests in a controlled environment. According to him, the values generated in the two tests varied by nearly 50%.
Another participant stated that he simply did not trust any portable PMI instruments. As he put it: “if you want a carbon analysis, we’re going to get a sample and take it to the lab for analysis.” He went on to add that this was not just true for carbon, but for hydrogen, oxygen, and sulfur.
Permanently Installed UT Sensors
Everyone in the room was aware of permanently installed UT sensors and had some level of experience with the technology. One participant stated they’ve successfully used these sensors in areas where they know they have variable active corrosion that they’re trying to keep track of (e.g., hot oil circuits on crude units). But, he cautioned that “you must remember that these should NOT be used in-lieu of the inspector going out and doing things. They should be used to help tell the inspector when and where he should go out and do things.”
All were in agreement that the potential of these sensors could be very beneficial to their integrity management programs from a process monitoring, risk mitigation (e.g., narrowing IOWs), and safety standpoint. The problem right now is they are just too expensive to implement across their facilities. Most of the participants only used them for special applications.
CUI Inspection Technology
When Corrosion Under Insulation (CUI) was brought up as the next talking point, it quickly became clear that everyone in the room has similar challenges with inspecting for and mitigating corrosion on insulated equipment. One participant jokingly proclaimed “insulation is evil!” and most everyone expressed frustration that CUI is considered an “inspection problem.”
As one participant put it, “the reality is, CUI is a problem caused by poor design and decades of plant neglect.” Most facilities have damaged insulation everywhere due to poor care and a lack of respect for insulation systems (e.g., walking on pipes, putting chokers on it for chain falls, etc.). And, in addition to that, most facilities don’t even have a robust QA/QC process in place for installing insulation. So the inspection department ends up fighting this issue from the back end, as opposed to preventing it from happening in the first place.
The reality is, CUI is a problem caused by poor design, poor coating installation and decades of plant neglect.
With regards to CUI inspection, one participant simply said “there is no silver bullet; sometimes you just have to get after it.” He added that they’ve been bitten by PEC and other NDT technologies in the past and are quickly coming to the realization that sometimes you just have to strip everything and put a proper coating on it. They’re now taking a criticality-type approach in order to prioritize which equipment they strip and coat in order to mitigate CUI damage. However, he did note that “the effectiveness is only as good as your surface prep, so you really have to be on your game when it comes to QA/QC.”
Several others echoed this approach, stating that “a good, well-applied coating is God-like.”
Another participant said they have taken a different strategy – they have moved away from mitigation, just because it was so time-consuming and expensive and was not really reducing their risk fast enough. Now, their strategy now is not to fix or replace insulation or go in and paint a bunch of piping. They’ve elected to reduce their CUI risk by using real-time radiography to simply look for bad pipe and, based on the degree of damage, either replace or closely monitor. He believes this alternative approach has been really successful for them.
Another participant added that “the biggest contributing factor he’s seen to CUI problems is the disparity between our work processes; we work one way for routine work, another way for turnaround work, and a different way for major projects.” This causes a lot of problems that could have been prevented with a more coordinated approach between all parties at all stages.
HTHA Inspection Technology
High-Temperature Hydrogen Attack (HTHA) is a huge concern for everyone in the industry. As one participant stated: the fact is, due to recent incidents, “there are three failures that we cannot have right now in the refining industry: HTHA, Sulfidation, and now HF Alkylation.”
For HTHA inspection, time of flight diffraction, or TOFD, seemed to be the NDE technique of choice. But when it comes to TOFD, one participant said that there has been a learning curve with it across their sites. With TOFD, they are picking up a lot more things than expected. This means that they have to dedicate the necessary time to scrutinize the data in order to really understand what it is telling them.
Right now, everyone is fine-tuning their internal HTHA procedures and being ultra-conservative with their inspections, another participant said. The TOFD technique is so hyper-sensitive that you have to understand you will see a lot of false calls. No technician wants to under-call it, because they, and the operators, are all scared of missing something, he later added.
So how are you deciding what to inspect vs. replace when it comes to HTHA mitigation?
One respondent stated that, from an inspection perspective, he’s always pushing for replacement; but the reality is that it is not always economically feasible. So in choosing what to inspect, he first looks at susceptibilities (e.g., operates with a certain number of degrees near the Nelson Curve, equipment age, operating history, etc.). Then, once you’ve identified the susceptible equipment, you’ve got to decide what portion of it to inspect. He added that “we know stress is a big contributing factor, so we look at areas under higher stress first.”
There are some other advanced analysis tools currently offered by a few engineering companies for predicting damage indexes, but the participants had mixed reviews. One participant said they were still evaluating one such tool, but it was not driving their programs yet. Another participant, however, said they have had great success with it so far and have been amazed at how accurate it is at predicting damage. BUT… he went on to recommend that before you inspect, conduct a “proactive” FFS evaluation to determine the remaining life, because a lot of this HTHA equipment is designed to a zero-corrosion allowance, Division II stress allowables, and the damage tolerance is extraordinarily low.
He went on to say that he doesn’t inspect anything that they think might fail a FFS evaluation; instead, they choose to replace. However, if they do move forward with FFS and the prediction says it may not be fit for service today, they’ve then successfully applied acoustic emission technology. The key is to apply acoustic emission at STEADY STATE, because when you do this and hear noises, it’s not embedded flaws, it’s active cracking or HTHA. And what that allows is for them to isolate the areas they’re hearing the noises and do further inspection in those specific areas. He said it’s proven extraordinarily accurate.
Inspectioneering and Pinnacle would like to thank all of the participants for joining in this discussion of these critical issues and sincerely appreciates the dedication of their time to share their thoughts and experiences with our community.