Interpretation Response #PI-71-057 ([Memo: Internal])
Below is the interpretation response detail and a list of regulations sections applicable to this response.
Interpretation Response Details
Response Publish Date:
Company Name: Memo: Internal
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Country: US
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Response text:
SUBJECT: Interpretation of section 192.619(c)
FROM: TGC-20
TO: TSA-32
You have asked for an opinion on the effect the "grandfather" clause in
§192.619(c) vis-a-vis the requirements in §§192.607 and 192.611 that an MAOP
of a pipeline which is not commensurate with its present class location must be
confirmed or revised in accordance with §192.611.
When Part 192 was issued, the preamble indicated the primary purpose of the"grandfather" clause was to avoid reductions of the existing MAOP's because the
pipeline was only tested to 50 p.s.i.g. above MAOP or because the pipeline was
operated at pressures above the design stress levels permitted under §192.619(a).
However, the right conferred by this "grandfather" clause are somewhat
circumscribed by the phrase "subject to the requirements of §192.611".
Section 192.611 was derived from provision in the ANSI B31.8 Code (850.42)
which was specifically limited to pipelines in Class 2, 3, or 4 locations. Although
this limitation was not included in section 192.611, we note that the provisions of
that section can only be meaningfully applied to pipelines in Class 2, 3, or 4
locations. Nowhere in this section is there a reference to a pipeline in a Class 1
location.
Therefore, it is our opinion that pipelines in Class 2, 3 and 4 locations must have
their operating pressures confirmed or revised in accordance with section 192.611.
However, pipelines in Class 1 locations operated at pressures which are not
commensurate with that class location, based on the design stress levels of section
192.619(a)(1), may continue to operate at their previous MAOP under the"grandfather" clause of section 192.619(c). In answer to your specific questions --
the first pipeline could continue operations at the stress level of 75% of SMYS;
pressure in the second or third pipeline would have to be confirmed or revised in
accordance with section 192.611.
William D. Broderick