Pressure testing and recordkeeping, reconciling historic pipeline practices with new requirements


    Originally published in Southern California Gas Company, on February, 2013

    This paper reviewed the history of industry standards and regulatory requirements in the areas of hydrostatic pressure testing and recordkeeping. The review shows that hydrostatic pressure testing after construction was not required by applicable industry standards (ASME B31.8) until 1955.

    The technology for pressure testing cross-country gas pipelines was not developed until 1950. Prior to 1955, operating pressure was established by the pipe mill test or an engineering calculation. Post- construction tests were discretionary, and generally for detecting leaks at flanged or welded joints above ground. Industry standards were referenced by some state regulations (e.g., GO 112 in 1961) until the issuance of federal safety regulations in 1970.

    Recordkeeping requirements began with welding quality control. In 1955, hydrostatic test records and those necessary for executing the operator’s O&M plan were required. Of test records, only test fluid and test pressure were required, and then that requirement only pertained to pipelines operating at a hoop stress of 30% or more of SMYS. It was thought at that time that engineering specifications and commercial documents were adequate to demonstrate practices. Additional recordkeeping requirements were imposed by federal safety regulations in 1970, including for hydrostatic pressure testing.
    When federal regulations were issued in 1970, several options were available for establishing the MAOP of existing (“grandfathered”) pipelines that did not rely on a documented post-construction pressure test. This establishes that for the past 50 years, the regulators have accepted that documents supporting the MAOP could be incomplete. In that context, the tests set forth in ADB- 2012-06 represent new standards that should not be used to judge whether an operator has complied with prior standards for that purpose as part of the ratemaking process.
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