In this episode of the Pipeliners Podcast, Russel Treat welcomes Mike Cloward of ExxonMobil, co-chair of the committee behind API RP 1192, the new recommended practice for the transportation of carbon dioxide by pipeline. The conversation covers why the industry developed the standard, what makes CO2 unique as a pipeline fluid, and how the recommended practice addresses integrity, fracture control, and emergency response. Mike also shares where the standard may go from here and advice for operators new to CO2 service.

Views expressed are those of the speakers and do not necessarily reflect the views of their employers, affiliated organizations, or any regulatory agency. Discussion of regulatory developments and industry standards reflects the speakers’ understanding at the time of recording and may change. For authoritative information on the incidents, standards, and regulatory actions discussed, please refer to the source documents linked below.

API RP 1192 Transportation of CO2 by Pipeline Show Notes, Links, and Insider Terms

• API RP 1192 (Transportation of Carbon Dioxide by Pipeline) is the new API recommended practice, released in December 2025, covering the design, construction, operation, and management of CO2 pipelines in gas, liquid, and supercritical phases.
• ExxonMobil Low Carbon Solutions is the ExxonMobil business line focused on carbon capture and storage and other lower-emission solutions, which Mike supports in his CO2 pipeline work.
• Denbury is a longtime CO2 pipeline and enhanced oil recovery operator acquired by ExxonMobil. Denbury operated the pipeline involved in the 2020 Satartia incident.
• LaBarge, Wyoming is the site of ExxonMobil’s long-running CO2 capture operations, where geologic CO2 is separated from produced gas and has historically been sold for enhanced oil recovery.
• Enhanced Oil Recovery (EOR) is the injection of CO2 into an oil reservoir to increase production. Russel refers to this as tertiary recovery.
• Geologic vs. Anthropogenic CO2: Geologic CO2 is naturally occurring and produced from underground formations, typically at high purity. Anthropogenic CO2 results from human activities, such as fertilizer, ammonia, and hydrogen plants, and often carries a different mix of impurities.
• Carbon Capture and Sequestration (CCS) is the process of capturing CO2 emissions at the source, transporting them by pipeline, and storing them underground. Mike advocates for “CCTS” to recognize the transportation piece.
• Satartia Incident refers to the February 2020 rupture of a Denbury CO2 pipeline near Satartia, Mississippi, caused by a landslide. The CO2 plume reached the town and led to evacuations and hospitalizations, and it raised major questions about CO2 dispersion and emergency response.
• Episode 346: Pipelining from a First Responders Perspective with Jack Willingham is the earlier Pipeliners Podcast episode with the county emergency manager who responded to the Satartia incident.
• Geohazard is a natural geological hazard, such as a landslide, that threatens pipeline integrity. A landslide was the root cause of the Satartia rupture.
• Dispersion Modeling is the analysis used to predict how a released fluid travels through the atmosphere. For CO2, it must account for the gas being heavier than air and for topographical effects.
• Simple Asphyxiant vs. Chemical Asphyxiant: A simple asphyxiant displaces oxygen in the air. RP 1192 uses the term chemical asphyxiant for CO2 to reflect that it can also interfere with the body’s ability to take up oxygen.
• PHMSA (Pipeline and Hazardous Materials Safety Administration) is the U.S. DOT agency that regulates pipeline safety and participated in the RP 1192 working group meetings.
• PHMSA CO2 Notice of Proposed Rulemaking (NPRM) was a proposed rule to strengthen CO2 pipeline safety requirements that was announced in January 2025 and later withdrawn following the change in administration.
• OMB (Office of Management and Budget) is the federal office that reviews proposed rules before they are published in the Federal Register.
• 49 CFR Part 195 is the federal regulation governing the transportation of hazardous liquids by pipeline, which explicitly covers CO2 pipelines.
• Incorporation by Reference (IBR) is the process of adopting all or part of an industry standard into federal regulation, giving it regulatory weight. A work group is currently developing recommendations to PHMSA on incorporating portions of RP 1192.
• Supercritical / Dense Phase: CO2 above its critical temperature and pressure behaves with the density of a liquid and the viscosity of a gas, which allows efficient transport of large mass flows with limited pressure drop.
• HVLs (Highly Volatile Liquids) are fluids such as ethylene that behave similarly to dense phase CO2 inside a pipe but, unlike CO2, are flammable.
• Dry Ice is solid CO2 that can form when pipeline CO2 is released to the atmosphere, creating extremely cold conditions near a release.
• Other Constituents is the term RP 1192 uses for impurities in a CO2 stream, such as water, oxygen, H2S, NOx, and SOx.
• Carbonic Acid Corrosion is internal corrosion that occurs when free water is present with CO2. It is managed primarily through dehydration and moisture monitoring.
• Strong Acid Formation is a degradation mechanism in which water, oxygen, H2S, NOx, and SOx interact to form acids such as sulfuric acid, even when water is below its solubility limit.
• Institute for Energy Technology (IFE) is a Norwegian research institute studying impurity interactions and safe limits in CO2 transport.
• Ohio University Institute for Corrosion and Multiphase Technology (ICMT) is a U.S. research center conducting testing on corrosion in CO2 systems with multiple impurities.
• Custody Transfer Point is the location where a product changes ownership, and where CO2 composition must be monitored and enforced.
• Fracture Control covers fracture initiation, propagation, and arrest. CO2 decompression behavior makes running ductile fractures a unique concern that RP 1192 addresses in detail.
• Ductile-to-Brittle Transition Temperature is the temperature below which steel shifts from ductile to brittle behavior, a key design parameter for avoiding brittle fracture initiation.
• Battelle Two-Curve Method is a model that compares the decompression wave speed of the fluid with the fracture propagation speed of the pipe to assess the risk of a running ductile fracture.
• Crack Arrestors are steel or composite external sleeves installed around a pipe to stop a propagating fracture, with an emphasis on protecting populated areas.
• Environmental Defense Fund (EDF) is an environmental advocacy organization that had a representative in the RP 1192 development process.
• Pipeline Safety Trust (PST) is a nonprofit pipeline safety advocacy organization that commented on the draft RP and hosted a March 2026 webinar on RP 1192 featuring API’s Mark Piazza.
• ANSI (American National Standards Institute) accredits the API standards development process, which requires every ballot comment to be reviewed and addressed.
• API CO2 Fact Sheet
• NASFM Pipeline Emergencies Training is the National Association of State Fire Marshals training portal, which hosts the CO2 pipeline emergency response training developed with API.
• CO2 Emergency Response Tactical Guidance Document is a guide published by API and LEPA (Liquid Energy Pipeline Association) with operator input, including lessons learned from Satartia, to help first responders prepare for and respond to CO2 pipeline incidents.
• PRCI Emerging Fuels Institute is the Pipeline Research Council International program focused on research for next-generation fuels such as hydrogen and CO2. Mike chairs its CO2 committee.
• ASME B31.8S Nine Threats is the integrity threat categorization framework (including external corrosion, excavation damage, and geohazards) that Mike references to distinguish what is managed the same way for CO2 pipelines and what is different.

API RP 1192 Transportation of CO2 by Pipeline Full Episode Transcript

Announcer: Welcome to the Pipeliners Podcast, episode 461, sponsored by Flowstate, providers of pipeline leak detection software built to remove barriers and empower operators. Flowstate helps teams detect anomalies, reduce false alarms, and improve response with practical tools designed for diverse pipeline operations. Learn more at FlowstateSolutions.ai.

The Pipeliners Podcast, where professionals, Bubbas, geeks, and industry insiders share their knowledge and experience about technology, projects, and pipeline operations. And now, your host, Russel Treat.

Russel Treat: Thanks for listening to the Pipeliners Podcast. I appreciate you taking the time, and to show that appreciation, we give away a customized YETI tumbler to one listener every episode. This week, our winner is Luis de Leon with TransMontaigne. Congratulations, Luis, your YETI is on its way. To learn how you can win this prize, stick around till the end of the episode.

This week, we speak with Mike Cloward of ExxonMobil about the new API 1192 standard on transportation of CO2 by pipeline. Hey, Mike, welcome to the Pipeliners Podcast.

Mike Cloward: Hey, Russel, good to be here. Thanks for having me.

Russel Treat: So we have asked you to come on board to talk about API 1192, which is the new standard for transport of CO2 by pipeline. Before we dive into that, would you tell me a little bit about yourself and about your background and how you came to chair that standard?

Mike Cloward: Yeah, absolutely. So I work for ExxonMobil. Most of my background is in pipeline integrity, so pigging, digging, hydrotesting, all those issues that your viewers are going to be familiar with. I have been working on CO2 pipelines for the last three to four years now, supporting ExxonMobil’s new Low Carbon Solutions business line.

So when Mark Piazza reached out to me with the opportunity to be the co-chair for this RP 1192 standard, serving with Khalifa from Oxy, I thought it would be a great opportunity to bring all those learnings to bear and share with the industry all the great work that’s been going on at ExxonMobil and other operators over the last few years.

Russel Treat: So Exxon acquired Devon a number of years ago, and Devon, not Devon, sorry, Denbury. But Denbury was a big player in CO2. They do a lot of CO2 for enhanced oil recovery and had a big system. So is Exxon, other than that acquisition, do they have other CO2 operations? Are they doing CO2 as well? Or what’s the nature of the other things that Exxon’s up to in the CO2 space?

Mike Cloward: Yeah. So even prior to the Denbury acquisition, ExxonMobil was involved in some CO2 operations. I think our primary asset is in LaBarge, Wyoming, where they are producing some geologic CO2 and venting it off to air. And actually, you know, the historic business model was some of that CO2 was sold to Denbury in some of the assets they have in the area there.

Russel Treat: Right. Yeah, yeah. Okay, great. So why the need for a standard for CO2 transportation? Because CO2 transportation has been around since the seventies, or earlier even, I think.

Mike Cloward: Yeah, that’s a great point. I think there’s a public perception that CO2 pipelines are new. And when you really look into the history and the mileage that’s out there, people have been doing it for decades. Like you said, you know, ExxonMobil’s been doing it since the eighties in Wyoming. Denbury’s been doing it for a long time as well.

I think what is new is not so much the CO2 itself, but the sources of CO2 and the end use of the CO2. So when you look at it historically, typically you had geologic CO2, which is pretty high purity, and it’s being used for things like enhanced oil recovery, like you mentioned.

But the new business model, as we start being focused more on, you know, reducing carbon emissions and a green economy in the United States and globally, we’re now talking about anthropogenic CO2, which means CO2 resulting from human activities. So we’re talking about things like fertilizer plants, ammonia plants, hydrogen plants. And a lot of these processes are producing very high purity CO2 streams just as part of their normal operation. And so they are pretty hard-to-abate emissions.

So what carbon capture and sequestration can do for us is take those CO2 emissions that are just going into the atmosphere today, capture them, transport them by pipeline, and then store them in the ground for either enhanced oil recovery or permanent storage.

Russel Treat: So I guess another way to frame that is because of green energy policy and the need to do carbon capture and sequestration. Again, we’re using big words. And so capture is grab it off of the producer, like the hydrogen plant or the, you know, the ethane cracker or whatever. And then sequestration is put it in the ground, right? Basically.

So what’s new is not really capturing the CO2, moving it by pipeline, and putting it in the ground. What’s new is we were capturing it from a geologic formation, moving it by pipeline, and putting it in the ground in an oil field in order to improve oil production. And now what we’re doing is we’re capturing it off of waste streams from facilities, moving it by pipeline, and putting it in the ground to keep it from going into the atmosphere.

Mike Cloward: Yeah, that’s exactly right. So as you said, CCS has been around for a while, but the particulars of how it’s done are evolving. And I’m actually on a personal mission, Russel, to get another letter in that acronym. So instead of CCS, I’d love to call it CCTS, to recognize the transportation piece as a pipeliner. We’ll see if there’s any update on that.

Russel Treat: That’s awesome. That’s awesome. As you say that, I immediately have two reactions. One is, that’s brilliant, I think we should do that. And the other is, yes, but do we want them to know? Should we operate quietly, and that way nobody knows about us? That way, if we’re doing our jobs right, then people aren’t thinking about it, right?

Mike Cloward: Being a pipeliner is like being an offensive lineman in football. You only get your name on the PA when you mess up.

Russel Treat: Fair enough. Okay, so we probably ought to talk about, you know, again, I asked the question about why the need. So one context is just the public interest and the public concern about CO2. The other thing I think that’s also true is we had an incident in Satartia. In fact, one of the people that I have met and have had on the podcast is a guy named Jack Willingham, who was the county emergency manager during that incident. And if you want to hear about that, that’s podcast episode 346 with Jack Willingham. We talked about the incident.

But that incident was significant because it was a CO2 pipeline rupture, and there were a lot of challenges with the incident response because it was CO2 and it was being responded to like it was a hydrocarbon pipeline. And the risks and the issues are materially different. So anything to add to that about Satartia? Did that influence what you guys did on 1192 and how you went about determining what needed to be in the standard?

Mike Cloward: Yeah, absolutely. I think Satartia was a major event for the CO2 industry, and it really brought CO2 pipeline safety to the forefront. When you really dig into that incident, you know, recognizing that the core, the root cause, was essentially a landslide, a geohazard. And the interesting thing about that is it didn’t really matter what was in the pipeline in terms of the root cause of the event. Like, if that had been a hydrocarbon pipeline, the same thing could have happened, right?

But as you mentioned, what mattered was the way it was responded to and the way that the CO2 itself traveled, right? We know CO2 is heavier than air. It ended up going farther than had been anticipated, despite doing some industry-standard dispersion modeling beforehand. That is essentially the perfect storm of factors: environmental conditions, low wind speeds, all that, that ended up taking the CO2 all the way to the town of Satartia.

So there are definitely some learnings there related to improving our dispersion modeling, capturing topographical effects, and really working with the local communities and first responders to let them know that there are CO2 pipelines in the area, helping folks understand how to appropriately respond to those CO2 releases and what the threats are to the members of the public.

Russel Treat: Yeah. So I want to unpack that a little bit for the listeners. And I know a lot of listeners will know exactly what you’re talking about, but for those that don’t, I want to unpack it a little bit. So when you think about consequence modeling, think about the difference between natural gas and crude oil.

So with natural gas, when you have a rupture, that natural gas goes into the atmosphere, and the risk is it finding a source of ignition and creating a flame. And then it’s the flame that does most of the damage if there’s a natural gas incident.

And crude oil is completely different. If I have a rupture in crude oil, what happens there is that crude oil, like water, flows to the lowest point that it can reach. And the risk there is it finds a watershed, and that watershed impacts wildlife and human life and that sort of thing. So two identical incidents, very different consequences.

And what you have with CO2 is a third kind of consequence that manifests in a completely different way. And the risks are different because CO2 displaces oxygen and it’s heavier than air, so it finds a low spot and stays there. You also get, when CO2 in a pipeline hits the atmosphere, it flashes to gas and to dry ice. Dry ice is minus one hundred and twenty-seven centigrade, I think, Fahrenheit, I don’t remember. It’s been too long. Very cold. And you end up with a dry ice snow that impacts things as well. So it’s just a very different kind of fluid and consequently has very different kinds of risks.

Mike Cloward: Yeah, absolutely. There’s been an ongoing discussion about how do you actually classify CO2. Some standards and bodies would refer to it as a simple asphyxiant, which means it’s just displacing the air and removing the oxygen from the environment.

In RP 1192, we actually get into a little bit more discussion on that, on the physiological effects of CO2. And we use the term chemical asphyxiant, which means that in addition to just displacing the oxygen around a population, you could potentially have some interference with the body’s ability to uptake oxygen. But for all intents and purposes, it’s quite similar to a simple asphyxiant, and it should be responded to as such.

Russel Treat: Yeah. Well, the other thing to state about CO2 is it’s all about concentration, right? Because every day we’re all breathing CO2. It’s a major part of what’s in the atmosphere, just naturally. But when you get into very high concentrations, depending on the concentration, it could be just an asphyxiant, or at an extremely high concentration, it could be something even more serious, because when you do get back to oxygen, your body has to purge itself of all that CO2.

Mike Cloward: Yeah, exactly. It’s, as you mentioned, a third type of consequence that we need to be prepared to respond to. And again, that’s why working with local communities and first responders is so important.

Russel Treat: Right. So let’s talk a little bit also, and I know that there’s some stuff going on at PHMSA around rulemaking for CO2. Can you talk about that? And did that have influence on what you were putting in the standard?

Mike Cloward: Yeah, absolutely. And I think, going back to the initial question of what was the driver for this standard, everything that was going on with the proposed rulemaking at the same time was another driver for us.

So the history, as I understand it, is around the first quarter of 2024, we heard that PHMSA had sent a notice of proposed rulemaking over to the OMB, and it spent a good amount of time there. And I want to say mid-January 2025, it was sent over to the Federal Register, but not published in the Federal Register, this notice of proposed rulemaking that was going to strengthen regulations around CO2 pipelines. And then with the change of administration in January of 2025, that rulemaking was paused, or terminated, you could say.

And so we did have an opportunity through API and other bodies to review what PHMSA posted to their website with that notice of proposed rulemaking. We could really understand the rationale behind a lot of the things PHMSA was asking for. We didn’t necessarily agree with everything they were asking for, where some things could be considered on the onerous side without much risk reduction benefit. But we could see the spirit of what was behind it.

And so when that rulemaking didn’t move forward, we knew that there was a lot of concern from the public still thinking that CO2 pipeline regulations should be strengthened. And so in my mind, what RP 1192 really represents is a good faith effort by industry to try to close some of those gaps that were left out there when that notice of proposed rulemaking did not move forward.

But another point I want to make as well on CO2 regulations, Russel, is that there’s also some level of perception out there that CO2 pipelines are not regulated. And that’s not true. CO2 pipelines, at least those that are in the supercritical phase, or what we might call dense phase in the industry, are explicitly regulated by CFR 195. So there are hundreds of provisions in CFR 195 that do apply to CO2 pipelines. There are some specific factors and threats relevant to CO2 that could be strengthened and more explicitly captured in regulations and industry standards, and that’s where RP 1192 comes in.

Russel Treat: Yeah. No, that’s a really excellent point, Mike. You know, what you’re saying is CO2 pipelines have been covered for as long as there has been a Pipeline Safety Act in play in the United States, right? And they have been covered under 195, as are all other liquid pipelines, you know, all petrochemical pipelines, crude oil pipelines, et cetera, et cetera.

But I think what’s important to understand is PHMSA, the public, and in fact the industry have recognized that there are some things about CO2 that are unique and have not been adequately addressed.

Mike Cloward: Absolutely.

Russel Treat: And that’s the purpose of 1192, is to close that gap. Okay, do all the things you need to do for a liquid pipeline, plus, if you’re CO2, implement this standard.

Mike Cloward: That’s exactly right. And I’ll also add, the RP does explicitly address both phases, or you could say all phases of CO2, depending on how you count.

Russel Treat: Right, right, right. Gas, liquid, supercritical, et cetera. And we ought to talk a little bit about that too, because that’s one of the things that makes CO2 unique. We’ve talked about the nature of, you know, an incident response and how CO2 is unique. We should also talk about just the fluid itself and how it’s unique.

So I’ll give, I don’t think we talked about this when we were teeing this episode up, but my first job out of the Air Force was as a CO2 applications engineer for Airco Industrial Gases. And I did a lot of work for about five years with CO2. Later, in the history of our company, we put together a CO2 flow computer, and we actually implemented it on all of the custody transfer points along the Denbury pipeline. So we actually built a CO2 flow computer.

So the thing about CO2 that makes it unique is that in a pipeline, it exists as a liquid, as a fluid, as a gas, and as something that is a combination of both. That’s called supercritical, which is basically a weird-behaving semi-fluid.

Mike Cloward: Exactly.

Russel Treat: Yeah. It’s similar to things like ethylene and other kind of spongy liquids.

Mike Cloward: Yeah. It’s a fascinating molecule and fluid. And when you talk about supercritical, when you’re above the critical temperature, above the critical pressure, I’ve heard that it has the density of a liquid but the viscosity of a gas. You can obviously see the benefits there in terms of trying to move a lot of mass flow, but without too much pressure drop. So I think the comparison to ethylene is fitting. HVLs are probably the best comparison in terms of behavior inside the pipe. And we already discussed how it’s different, you know, there’s no ignition risk once it’s outside of the pipe, if it ever gets outside the pipe.

Russel Treat: Yeah. And that unique behavior, and the fact that it’s not a volatile liquid, meaning it’s not flammable, is one of the reasons it makes sense for enhanced oil recovery, because that behavior causes it to do some very helpful things in a formation. You know, what they call tertiary recovery. But anyways, we’re getting down a rabbit hole a little bit.

So tell us a little bit about what’s in the standard. What did the committee do? Because, you know, you’re not writing, you know, 195. You’re just trying to plug gaps. So tell us a little bit about what’s in the standard.

Mike Cloward: Yeah. So at a very high level, it is a recommended practice. So what that means is the RP contains a mixture of just background informational, educational material for the readers, but then it also contains a good number of “should” and “shall” statements, so actual standards and guidance for operators to follow.

So just a quick overview of what’s in the table of contents. It’s a very broad-reaching RP. It’s going to include everything from siting a pipeline to design, material selection, including non-metallic, unique considerations and integrity threats like internal corrosion, carbonic acid, fracture control, and how that’s different for CO2 pipelines. It gets into repurposing considerations, if you’re ever looking at changing service from a hydrocarbon to CO2, what things you need to think about and look at in your risk assessment. It covers how to monitor and enforce the composition of your CO2 stream. That’s very important for integrity management. There’s also…

Russel Treat: Okay, I want to pause you right there, because the other ones I kind of understood. So what are the issues related to CO2 purity, and how does that relate to integrity management? That’s interesting.

Mike Cloward: Yeah, that’s a great question. So if we were just transporting pure CO2, it would make all of our jobs a lot easier, because CO2 by itself would not be corrosive to carbon steel, and we would avoid a lot of the potential issues that we do deal with.

So the fact of the matter is we’re not transporting 100 percent pure CO2. We have impurities. We actually use the words “other constituents” in the RP. So things like water, oxygen, H2S, NOx, SOx, et cetera. So there are a lot of degradation mechanisms that can potentially come into play. But what it all really boils down to is controlling the water, right? So if we can keep the water to a manageable level, that helps avoid almost every other integrity impact that we’re concerned about.

And the most basic mechanism to think about in a CO2 pipeline is going to be carbonic acid corrosion. But for that to happen, you actually need to have a free liquid water phase in the pipeline. And for that to occur, you’re talking pretty high levels of water, like upwards of 2,000 to 3,000 parts per million. And with standard dehydration technologies on the market, you can easily get it well below that number. So 100 to 300 ppm is very achievable. If your dehydration system is operating properly and you’re monitoring your moisture levels, which is very, very easy to do, then you will not have to worry about carbonic acid corrosion.

There are other mechanisms, though, that can occur even when the water is below its solubility threshold. One of those is referred to as strong acid formation. So that’s a pretty complex interaction between five different impurities. You’ve got water, oxygen, H2S, and then post-combustion impurities like NOx and SOx. So those can all interact together and potentially form sulfuric acid, even when the water is below its solubility point.

So there’s a lot of really great work going on in that area. I’ll give a shout-out to the Institute for Energy Technology in Norway, as well as Ohio University in the United States, where they’re testing a bunch of different combinations of those five impurities and really helping operators understand what are the safe limits when you have all five of those things in combination.

So once you understand those limits, it’s now incumbent on the operator to have appropriate monitoring and analyzer equipment at custody transfer points, understand how things are mixing from different sources, and then take enforcement action, such as shutting in an emitter if they are exceeding their allowable limits.

Russel Treat: Yeah, that’s interesting, because the work I was doing in CO2 was all geologic CO2, and that CO2 had a pretty consistent composition. And the issues were more, you know, what were the hydrocarbon components and how was that affecting measurement? And of course, the water and the water concerns were kind of standard, because, you know, you’re talking about a very high concentration of CO2.

But when you start talking about waste stream capture, we have a bunch of other things in that waste stream that can impact other behaviors and other chemical reactions in the fluid that could impact the integrity of the system. So I never thought about that, but that makes a lot of sense.

Mike Cloward: Absolutely. And when it comes to composition in the RP, we’re pretty clear that there’s really no one right answer in terms of a universal CO2 spec, like you might see in the natural gas industry. And that’s because when it comes to setting the CO2 spec for a specific project, it’s very much an “it depends” kind of problem. You know, how much H2S or oxygen can I allow? Well, that depends on how much you have of other impurities that may be in the stream. It depends on the operating temperature and pressure, as well as what phase the CO2 is being transported in.

So for that reason, we didn’t prescribe a single CO2 purity limit, or impurity limit, you could say, for all the potential constituents that may be present. But what we do instead is try to educate the operators on what are the various degradation mechanisms associated with each impurity, and what are some safe limits that are available in the literature, based on modeling or test data or operational experience. And then it’s really incumbent upon the operator to understand those mechanisms and know what they have in their system.

Russel Treat: Yeah. No, that’s really interesting. I wouldn’t have anticipated that, but it makes a lot of sense. So anything else in the standard that we ought to talk about and dig into a little bit that maybe would be unique for people that are not familiar with CO2 to kind of understand?

Mike Cloward: Sure. Yeah. I think another really interesting topic that’s unique to CO2 is going to be fracture control. So there’s a whole section in the RP that discusses how to deal with fracture initiation, fracture propagation, and fracture arrest.

So in terms of fracture initiation, that’s probably pretty standard for anyone who’s familiar with fracture control. You need to design your pipelines to avoid ductile and brittle fracture initiation. So that means you need to specify the right ductile-to-brittle transition temperature and have the right wall thickness, strength, and toughness in your pipe steel.

But then when you start talking about propagation, that’s where it gets a little interesting for CO2. So the RP does give a lot of background educational information there about the underlying principles behind fracture control and what makes CO2 different. And it gives an overview of different models that could be used for assessing the susceptibility of fracture propagation in your pipeline.

And one of those is the Battelle two-curve method. So what that’s going to do is look at the decompression speed in the event of an unlikely release, so how quickly a decompression wave travels through the line, as well as the fracture propagation speed. So Battelle two-curve is going to compare those two things to each other.

When you look at CO2 compared to, say, natural gas, the decompression behavior of CO2 is unique, and it goes back to the phase behavior we talked about at the beginning. So we’re operating the CO2 in dense phase. As decompression occurs, obviously the pressure’s going to drop, but then as you reach the two-phase region, that can sustain the driving force for propagation at a higher pressure than what you might see in natural gas.

Russel Treat: And for a long… because you’re actually, with natural gas, the amount of gas you have in the pipeline is the amount of gas you have in the pipeline. With CO2, the amount of gas that’s in the pipeline is going to be expanding, because as you drop that pressure, that dense phase is going to flash to liquid and solid, most likely, depending on, you know, where you are in the phase. But basically, you’re going to be flashing, you’re going to be creating a greater volume of gas.

Mike Cloward: Exactly.

Russel Treat: So then that’s going to, again, it’s really, you know, I understand the hydraulics of that, but I’ve never really thought about the impact that would have on the steel itself.

Mike Cloward: Yeah, absolutely. Hopefully this is giving everyone a good teaser to go check out the RP and dig into these issues. So yeah, that topic is really interesting, and again, there’s some unique CO2 behavior going on there. But the important takeaway is all of these unique threats can be managed and can be done safely, which the industry has demonstrated for decades. And the RP, again, is trying to inform and educate the operators on what these threats are and then give them tools in their toolbox to be able to address these concerns.

So going back to the fracture control example, the RP is going to walk people through how you assess the line for fracture propagation, and what considerations you need to design to mitigate the risk of ductile fracture propagation. And then there’s also a pretty robust discussion on the use of crack arrestors. So those are external sleeves, which can be steel or can be composite, that you can put around the pipe, in the event that there is a fracture propagation, to prevent it from spreading. And really the emphasis is on protecting populated areas.

Russel Treat: Right. Yeah. No, it’s interesting. Very interesting. So was PHMSA involved in the standard writing?

Mike Cloward: Yeah. The standard development process is very open and collaborative. So there was essentially an open call from API to any interested parties or stakeholders. We had a lot of operators involved, service providers. There were folks from PHMSA involved in the working group meetings. They were able to listen in and provide occasional input. And then we also had a representative from EDF. We also had…

Russel Treat: I’m sorry, EDF, can you unpack that for me?

Mike Cloward: Oh, sure. That’s the Environmental Defense Fund.

Russel Treat: Oh, right. Right.

Mike Cloward: And then after the working group meetings had concluded, we had a draft of the RP. It was sent out for the balloting process, where people are given an opportunity to review and provide comments. We actually received over one thousand comments on this document. So it was, yeah, it was a lot of work to get through all that.

Russel Treat: I’ve served on some committees, and I’m used to maybe a few hundred comments, but over a thousand? I mean, wow.

Mike Cloward: Yeah. As we mentioned, this shows you the level of interest.

Russel Treat: Exactly.

Mike Cloward: And that’s what we want. We want to bring everyone to the table to talk through everyone’s concerns. And, you know, the API standard development process is ANSI accredited, and it requires us to review and address every comment. So we went through that process. During that commenting process, I believe we also received a good number of comments from the Pipeline Safety Trust, getting their perspective. And we really appreciated all the feedback that we received and, again, made a good faith effort to address everything to the extent possible in the RP.

Russel Treat: Yeah, I’ve had the guys from the Pipeline Safety Trust on the podcast a number of times. I really like the work they do. I don’t always agree with the positions they take, but I really like the work they do. It’s what used to be called the loyal opposition, right? They’re very good at bringing a public perspective into the process around pipelines. They do an excellent job of that.

Mike Cloward: Absolutely. I was glad to have their input. And then they actually invited API to attend a webinar. I think it was back in March of this year, and Mark Piazza of API came and gave a presentation on RP 1192. I don’t want to put words in anyone’s mouth, but I was able to listen to the webinar, and my perception is that it was very well received by PST, that they could see the effort that industry was making to develop this standard and, again, try to close some of the potential gaps that may be out there on the regulatory side.

And one of the questions that we got in the Q&A part of that webinar was, is there any interest from PHMSA in trying to IBR, incorporate by reference, portions or the entirety of RP 1192 into the CFR? So it was really nice to see that folks have looked at the RP and think we have a high quality work product and want to see it codified into the law.

And so, following that thread for a second, we’ve been in conversations with PHMSA about the potential to incorporate by reference portions of the RP. We have a work group of people that helped develop the RP getting back together right now to make recommendations back to PHMSA, going through some of the specific things we talked about: composition control, fracture control, dispersion modeling, emergency response, all of those items, and try to flange those back up into the CFR so that we can have some regulatory weight behind the recommendations that are in the RP.

Russel Treat: Excellent. So what is API up to beyond that? I know a lot of times when there’s an issue like CO2 that has a lot of public interest, API will do other things beyond just the standard. So what else is API up to?

Mike Cloward: Yeah, absolutely. So in addition to the RP, they’ve developed some fact sheets. Those are just one-pagers on some specific topics. My understanding is those are free to the public and can be accessed on API’s website. So those are going to be more bite-sized educational material that will cover one topic at a time. You know, there’s one on equations of state that describes the thermodynamic behavior of CO2. There’s stuff on dispersion modeling, emergency response, et cetera.

In addition to that, there’s also a training that’s been developed in conjunction with NASFM, the National Association of State Fire Marshals. The training can be accessed on the NASFM portal. Again, my understanding is that training is free of charge. And so really trying to get this information out in front of the public, in front of the first responders, and disseminate everything, because there’s a lot of good work that’s been done, and it’s not going to have the impact that we want if we’re not getting it out in front of people.

Russel Treat: Right. So just for the listeners, of course, you can always go to the API website and look for these things, but we will make sure in the show notes on the Pipeline Podcast Network website to link all that stuff up, so that maybe makes it a little easier to find.

Mike Cloward: Sounds great. Yeah. One other thing I wanted to mention is the, I think it’s referred to as the CO2 Emergency Response Tactical Guidance. That’s a document that was developed by API and LEPA, and I know it had input from multiple operators, including ExxonMobil and Denbury. That’s a really high quality document as well. That’s going to give very specific guidance, with learnings from the Satartia incident that we referenced at the beginning of our discussion, to help first responders know how to not just respond to, but also how to prepare for, any potential incident.

Russel Treat: Yeah. Well, look, this is excellent. I think the last question I’d like to ask is, for any pipeliner who’s moving into CO2, or for any pipeline company that’s looking at doing a CO2 pipeline and hasn’t done it before, what would you tell them as to how to start?

Mike Cloward: Well, maybe it’s too shameless of a plug, but get yourself a copy of RP 1192. It’s about educating yourself. And, you know, there are other organizations as well that are working hard on addressing these concerns, you know, Pipeline Research Council International. And another shameless plug, there’s the Emerging Fuels Institute. I’m actually currently serving as the chair for the CO2 committee there, where we’re taking everything that we wrote down in the RP, identifying where the leading edge of the knowledge is and where the knowledge gaps are, and we’re doing research on those projects right now.

But yeah, where to start if you’re new to CO2, but maybe not new to oil and gas pipelines? I think your first order of business is understanding what’s the same and what’s different, right? So if you think about, you know, the nine threats of ASME B31.8S, anything external to the pipeline, external corrosion, excavation damage, geohazards, that’s all essentially managed the same for a CO2 pipeline. But what’s different, and again, RP 1192 is going to give you a really good crash course in what those unique considerations are and how you can safely address those items.

Yeah, I think my takeaway that I would say is, don’t assume that a CO2 pipeline is like any other 195 liquid pipeline. That is a good way to get yourself in trouble.

Russel Treat: That’s a great comment, Mike, and I think we’ll leave it there. Focus on what’s the same, and focus on what’s different. Make sure you understand what’s different and have a plan for how to deal with it.

Mike Cloward: Absolutely.

Russel Treat: Yeah. Well, hey, thanks to you for taking the time to do this, and thanks to ExxonMobil for allowing you to take the time away from your day job to do these things that are so important for the industry overall.

Mike Cloward: Yeah, absolutely. Thank you for having me. It’s been a great opportunity to discuss this with you.

Russel Treat: I hope you enjoyed this week’s episode of the Pipeliners Podcast and our conversation with Mike. Just a reminder, before you go, you should register to win our customized Pipeliners Podcast YETI tumbler. Just visit PipelinePodcastNetwork.com/Win and enter yourself in the drawing.

If you have ideas, questions, or topics you’d be interested in, or if you’d like to be a guest, please let me know either on the Contact Us page at PipelinePodcastNetwork.com, or reach out to me directly on LinkedIn. Thanks for listening. I’ll talk to you next week.