Progress: Not Addressed
DOT Relevance: 192.609 192.611
The subject of change in class location falls under the Subpart L (Operations) of 49 CFR 192. Class location refers to the distance a structure must be located from the pipeline. A class location unit is defined in 49 CFR 192 as an on-shore area that extends 220 yards on either side of the centerline of any continuous 1-mile length of pipeline.
The parameters for class location are based on natural gas considerations. The underlying definition of class location should be reviewed for hydrogen.
ASME B31.12 plans on following the ASME B31.8 code with input from the modified section 3.2 of ASME B31.8S.
Standards should be established for change in class location of hydrogen pipelines and incorporated by reference into the federal code including what the maximum allowable operating pressure of the hydrogen pipe should be and at what population density is a change in class location warranted. The class location unit needs to be revisited to confirm whether it is appropriate for hydrogen. The change in class location criteria in 49 CFR 192 also should be revisited.