CO₂ Transport Changes the Integrity Basis

This white paper examines why carbon dioxide pipeline procurement cannot be reduced to selecting a conventional line-pipe grade or applying historic natural-gas assumptions. In CO₂ transport systems, the transported stream itself forms part of the integrity and qualification basis because composition, impurities, water content, pressure, temperature and phase behaviour can affect corrosion, decompression and fracture-control requirements.

The paper proposes a Stream-to-Pipe Integrity Envelope for buyer-side and EPC procurement. The framework links the approved CO₂ stream definition and decompression/fracture basis to material selection, pipe and weld evidence, qualification, production control, change management and final release.

Drawing on publicly available sources, the analysis considers the complementary roles of ISO 27913:2024, API RP 1192, API Spec 5L 47th Edition and DNV-RP-F104. These sources are treated according to their respective system-, product- and integrity-level purposes rather than as interchangeable requirements.

The paper highlights several procurement implications. CO₂ concentration alone is not a sufficient stream definition; impurities, water control, operating envelope and source variability also matter. Running-fracture control should be treated as a system problem in which pipe resistance is evaluated against the actual decompression behaviour, geometry and operating conditions. Numerical CVN, DWTT or fracture-mechanics acceptance limits should therefore come from the governing project method rather than be generalized across projects.

The framework also addresses multi-source CCUS networks and pipeline repurposing. Where streams from different capture sources converge, the approved composition envelope and interface responsibilities should remain controlled. Likewise, an existing hydrocarbon pipeline proposed for CO₂ service requires explicit re-qualification rather than automatic inheritance of its historic integrity basis.

A key proposition of the paper is that the CO₂ stream is part of the pipe qualification basis: if stream composition, decompression assumptions, operating conditions, material route or fracture-control methodology changes, the supporting integrity evidence may need to be re-evaluated.

An Execution Decision Point is included to connect consequential actions—such as pipe release, material substitution or configuration change—to the governing stream/integrity basis, current evidence, invalidating changes, responsible approval authority and a reviewable closure record.

This paper forms No. 10 of the From Mill to Project Independent Research Series — Phase II. It is an independent, manufacturer-neutral practitioner research paper based on publicly available information and author synthesis. It is not an engineering specification, certification scheme or substitute for project-specific pipeline, fracture, corrosion or integrity engineering.

Author-written abstract, reproduced from the authoritative Zenodo DOI record.