API RP 1192: The First CO₂ Pipeline Recommended Practice, and What It Decides Before the Pipe

Carbon dioxide pipelines have been regulated in the United States for years under the federal hazardous-liquid programme, but until December 2025 there was no industry recommended practice written specifically for moving CO₂ by pipeline. On 17 December 2025 the American Petroleum Institute announced the publication of API Recommended Practice 1192, Transportation of Carbon Dioxide by Pipeline — a first-edition document giving performance requirements for the design, construction, operation and management of CO₂ pipelines, focused on the supercritical and liquid phases and including gas-phase transport. A document of this kind is where a compressor station's outlet stops being a project decision and becomes an industry convention.

This article sets out what the recommended practice is, why CO₂ needed a document of its own, where the compression train enters its logic, and where the public record stops. It is not a compliance determination.

What did API publish?

A first-edition recommended practice for the whole life cycle of a CO₂ pipeline.

API's announcement describes RP 1192 as performance requirements for the safe and reliable transport of carbon dioxide by pipeline, addressing design, construction, operation and management. Its technical coverage, as listed by the publisher, includes operating pressure ranges, ductile fracture control, pressure fluctuations, corrosion considerations and interactions with non-metallic components, alongside guidance on repurposing existing pipelines for CO₂ service and on emergency response planning specific to CO₂ releases.

The document's stated emphasis is on CO₂ transported in the supercritical and liquid phases, with gas-phase transport included. That emphasis matches how long-distance CO₂ actually moves: the dense phase is where pipeline transport becomes economical, and it is also where CO₂ stops behaving like the fluids the existing pipeline literature was written for.

Why does CO₂ need a pipeline document of its own?

Because CO₂ fails a pipeline differently from the liquids the existing framework was built around.

A petroleum liquid pipeline fails by leaking. A dense-phase CO₂ line can fail by tearing: CO₂ depressurises with a strong cooling effect and a phase change, and a breach can propagate as a running ductile fracture over long distances if the steel's toughness and the arrest design do not account for the gas's decompression behaviour. That is why fracture control appears as a named topic in the new document rather than as an inherited assumption.

Two further differences sit behind the document's contents. CO₂ streams are rarely pure: the impurities a capture process sends downstream — water among them — change both the phase behaviour and the corrosion mechanisms, which is why corrosion and stream composition run through the recommended practice. And CO₂ in the dense phase interacts with the non-metallic parts of a system — seals, gaskets, liner materials — in ways hydrocarbon service does not reproduce, which is why those interactions are named as well.

Where does the compression train enter the picture?

At the document's starting boundary: the operating pressure range a pipeline is designed for is delivered by the compression or pumping system upstream of it.

Whether a CO₂ stream travels as a gas or in the dense phase is decided before the pipe — by the pressure the compression train establishes and holds. A pipeline designed around dense-phase operation presumes stations that keep the stream above the phase boundary through the route's pressure and temperature envelope; a repurposed line with a lower pressure rating pushes the same question back onto the upstream machines. The recommended practice's treatment of operating pressure ranges and pressure fluctuations is, from the machine side, a statement about the duty the compression and booster equipment must hold — a boundary condition written in pipeline language.

That is also why the document matters beyond pipeline engineers: the phase decision it encodes is the same decision that sets the number of compression stages, the interstage cooling and the discharge conditions at the capture site's outlet.

What is the document's legal status?

A recommended practice — industry convention, not law — and explicitly positioned as input to the regulator's own rulemaking.

API's own taxonomy, as presented in a March 2026 briefing to the Pipeline Safety Trust, separates recommended practices from specifications and standards: an RP communicates recognised industry practices and may contain both mandatory and non-mandatory elements. The same briefing states the development basis directly — the infrastructure build-out expected from carbon capture, the intent to complement existing consensus standards, and the aim of supporting the Pipeline and Hazardous Materials Safety Administration's pending rulemaking on CO₂ pipeline safety. In other words, the industry document is written to be absorbed into federal regulation later, through the same incorporation-by-reference route that other API documents have travelled.

That positioning is itself the news for anyone upstream of the pipe: the practices being consolidated now are the practices a future federal rule is likely to borrow.

Where does the public record stop?

At four places — and each of them is a point where the public documents around this document genuinely end.

The text is a paid document. This article records the publisher's announcement and a public briefing about the document; it has not read the recommended practice and does not summarise its provisions.

Adoption is not scheduled. The regulator's rulemaking is pending, and neither the announcement nor the briefing commits to a date on which RP 1192 might be referenced by regulation.

Repurposing guidance is named, not detailed, in public. How an existing line is evaluated for CO₂ service is inside the document, not in the public record around it.

Nothing here determines any system's compliance. The recommended practice is voluntary unless a rule or a contract invokes it, and this article makes no determination for any project.

What does the trend add up to?

Three movements, all of them documented in the public record around the publication.

The CO₂ infrastructure chain is getting its own text at each link — capture-side rules, storage frameworks, and now the transport link between them. The industry is writing practice down before the regulator writes rules, and saying so openly. And the phase question — gas versus dense phase, the decision that defines both the pipe and the machines feeding it — is now the opening subject of an industry document rather than an engineering aside.

For the machine side, the message is indirect but real: the pressure envelope a CO₂ pipeline is designed around is becoming a matter of published practice, and the compression duty will be read against it.

What this article does not cover

Note that this article does not reproduce the recommended practice's requirements, does not evaluate any pipeline or compression project, does not predict the federal rulemaking's content or timing, and gives no prices. It records the publication and the publicly stated scope of a first-edition industry document. It is not a compliance determination.

Where the next constraint sits

The phase decision this document opens with — gas or dense phase, and the pressure each implies — is worked through from the machine side in Compressing CO₂: The Pressure Is Set by the Phase, Not by the Distance.

And what the dense-phase duty does to the compressor itself, at the scale of an eight-stage integrally geared machine, is set out in Supercritical CO₂ Compression: What an Eight-Stage Integrally Geared Machine Changes.

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