Application of a 10-Inch Pipeline for Natural Gas Containing H₂S

This page features a question from a user concerning the application of a 10-inch pipeline, which carries natural gas containing 250 ppm by volume of H₂S and is pressurized to 475 psi at 152°F. The pipeline runs from a gas compressor to a turbine generator, and the user intends to use 304L SS, which satisfies the requirements in A.2. The user seeks guidance on what table from Annex A applies to this pipeline.

Environmental and Materials Limits for Austenitic Stainless Steels

The answer provided outlines several points, stating that Table A.6 of NACE MR0175/ISO 15156-3 provides environmental and materials limits for austenitic stainless steels used in compressors. Meanwhile, Table A.2 applies to austenitic stainless steels used for any equipment or components. The latest editions of API Standard 618 and 617 for reciprocating compressors and axial/centrifugal compressors respectively define the scope of equipment associated with the compressor environment.

Determining Pipeline Service Conditions

It is the user’s responsibility to determine if the pipeline is directly associated with the compressor and thus experiences the same service conditions outlined in NACE MR0175/ISO 15156-3, Table A.6. The Maintenance Panel cannot interpret individually designed equipment and pressure stations.

Documenting Previous Experience with Pipelines

The manufacturer and user may consider documenting previous experience with pipelines in accordance with NACE MR0175/ISO 15156-1, Paragraphs 8.2 and 9.0. NACE MR0175/ISO 15156-1:2001 provides minimal requirements for these issues, and the user is ultimately responsible for ensuring that the chosen alloy can resist the types of cracking listed in the Scope 1.0 of NACE MR0175/ISO 15156-1:2001. However, the ISO Maintenance Panel cannot comment on the suitability of using 304L SS compared to other alloys.