Progress: Not Addressed
DOT Relevance: 192.14
A number of hydrogen pipelines in use today have been converted from earlier oil or gas use. Generally, these are derated relative to allowable percentage of SMYS. Under Subpart A (General) of 49 CFR 192, conversion of service refers to using existing in-ground pipe for service.
A number of assessments are typically performed prior to conversion, including research into service history, previous replacement and repair work, metallurgical analyses, reviews of right-of-way documents, etc. Parameters must be defined for standards for using existing in-ground oil or gas pipe for hydrogen service.
Requirements have been developed by a number of companies internally but there are not yet any public guidelines.
The ASME B31.12 task group has included a section on pipeline conversion in their draft document. Standards for conversion of service to hydrogen should be established and incorporated by reference into the federal code.