The purpose of this document is to provide guidance on materials selection and corrosion control for engineers in the design and identification of operating limits for projects that involve CO₂ transport and injection. It should be used as a guide to help identify specific requirements which can be tailored for each project rather than as definitive requirements used straight from the document. References are also made to other relevant documents and standards. The guidance provided for an initial design should help the engineer focus on the most critical issues related to CO₂ transport and injection. It is a rapidly growing subject area and much exploratory technical work is still being executed, and as such this document should be seen as a starting point with future updates and new insights to be expected.

Carbon and low-alloy steels in plate form and their welded products may be susceptible to one or more forms of environmental cracking when exposed to wet H₂S service conditions. These include, for example, (1) sulfide stress cracking (SSC) of hard zones and welds; (2) hydrogen-induced cracking (HIC) in the parent metal; and (3) stress-oriented hydrogen-induced cracking (SOHIC) in the region adjacent to welds of nominally acceptable hardness. Extensive work has been conducted over many years to understand various fundamental and applied aspects of these phenomena. Experiences in refinery wet H₂S operations have directed particular attention to understanding SOHIC and the various metallurgical and environmental parameters that govern its occurrence.

Scope

This standard was prepared to provide a test method for consistent evaluation of pipeline and pressure vessel steels to SOHIC caused by hydrogen absorption from aqueous sulfide corrosion. The test conditions are not designed to simulate any specific service environment. The test is intended to evaluate resistance to SOHIC only, and not to other adverse effects of sour environments such as sulfide stress cracking (SSC), pitting, or mass loss from corrosion.

This standard practice provides guidance on selecting and implementing the Pipeline Integrity Management (PIM) methods (i.e., technologies and processes) to assess and to mitigate threats to pipeline integrity. Predominant threats to pipeline integrity are external corrosion (EC), internal corrosion (IC), stress corrosion cracking (SCC), mechanical damage (first, second, and third party or vandalism), equipment malfunctioning, manufacturing anomalies, construction anomalies, incorrect operations, weather-related, and external forces. The standard is focused on the “selection” and “implementation” of methods and best practices to manage pipeline integrity, but not necessarily on defining all aspects of PIM programs.