Criticality: High Progress: Not Addressed Score: 40 DOT Relevance: §192.551 – §192.557
Description of Key Area
Under Subpart K of 49
CFR 192, the minimum requirements for increasing maximum allowable operating
pressure for pipelines are prescribed.
Discussion of Criticality
Today’s hydrogen
pipelines operate at stress levels generally between 30% and 40% of SMYS. To
increase pipeline capacity, increased pressures may be required. Increased
allowable stress levels can, in part, lead to cost-effective designs at higher
pressures.
Discussion of Progress
ASME B31.12 will use
only location class 3 and 4 for pipeline design. This will limit the percentage
SMYS utilized in design or uprating. The new code will provide location class
limits and incorporate “design factors” to maintain design conservatism until
actual research data on material properties is available. The design factors
will be used to restrict pipe stresses as the pressure increases and/or the
tensile strength of the pipe material is increased or both.
Recommendations
Research needs to be
performed to produce research data on material properties so that accurate
class limits can be set. Standards and procedures for the uprating of hydrogen
pipe should be established and incorporated by reference into the federal code.
