Interpretation Response #PI-94-010
Below is the interpretation response detail and a list of regulations sections applicable to this response.
Interpretation Response Details
Information: Interpretations of § 192.557
Cesar De Leon
Director, Technology and Standards Office
Director, Central Region
This responds to your note of November 7, 1993, which transmitted two old interpretations of § 192.557 and asked if they were still correct. The following changes apply:
Letter to John Searcy, dated March 11, 1974
The second sentence of the second paragraph incorrectly implies that the pressure test required in uprating under § 192.557 must be done concurrently with the uprating process. However, the source of the pressure test requirement, §192.619(a)(2)(ii), which limits MAOP on the basis of test pressure, does not prescribe the timing of the test pressure. So any previous test pressure (including any operating pressure that suffices as a test pressure) could qualify for uprating under§ 192.557. Only if the pipeline had not previously been pressure tested or if the previous test pressure were insufficient would the pipeline have to be pressure tested concurrently with uprating.
In addition, the last sentence of the second paragraph incorrectly implies that the incremental pressure increases required by §192.557(c) apply to pressure tests done concurrently with uprating. However, a comparable rule, § 192.555(e), requires incremental pressure increases only for pipelines that are not tested concurrently with uprating - pipelines that either were previously pressure tested or need not be pressure tested. Given this comparable rule, it is not reasonable to interpret § 192.557(c) to require incremental pressure increases during pressure testing.
Letter to William R. Johnson, dated May 6, 1974
As above, the second sentence of the second paragraph incorrectly implies that uprating under§ 192.557 requires concurrent pressure testing in all cases.
|§ 192.557||Uprating: Steel pipelines to a pressure that will produce a hoop stress less than 30 percent of SMYS: plastic, cast iron, and ductile iron pipelines|