[Federal Register Volume 61, Number 189 (Friday, September 27, 1996)]
[Notices]
[Pages 50900-50902]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-24863]
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DEPARTMENT OF TRANSPORTATION
Research and Special Programs Administration
[Docket No. P-96-8W; Notice 2]
CNG Transmission Corporation; Grant of Waiver
ACTION: Notice of grant of waiver.
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Summary
The Research and Special Programs Administration (RSPA) waives
specified operations regulations to permit CNG Transmission Corporation
(CNGT) to requalify the maximum allowable operating pressure (MAOP) of
ten line segments by a combination of hydrostatic testing of certain
segments and internal inspection(s) of the 26-inch diameter gas
transmission line. The need for requalification of the MAOP results
from a recent increase in population density that has caused the hoop
stress corresponding to the established MAOP to be incommensurate with
the present class locations. The 26-inch diameter portion of
transmission line TL-400 is located in central Ohio and the affected
line segments (totaling 10.91 miles) are spread throughout the 163.19
mile length.
Background
By a letter dated April 23, 1996, and supplemented by
correspondence dated May 2 and May 14, 1996, (cumulatively referred to
as the ``petition''), CNGT petitioned RSPA for a waiver from compliance
with the requirements of 49 CFR 192.611(a) that require confirmation of
the MAOP of the affected segments by hydrostatic testing. Instead, CNGT
proposed an alternative approach involving: a close interval pipe-to-
soil corrosion survey; certain hydrostatic testing; and the internal
inspection(s) of the entire 26-inch diameter transmission line with a
geometry pig followed by an
[[Page 50901]]
instrumented internal inspection device commonly known as a ``smart
pig''. Also, CNGT requested ( if needed) the extension of the 18-month
period for hydrostatic testing contained in Sec. 192.611(c), from
October 19, 1996, to June 30, 1997.
Alternative Approach
Rather than hydrostatically testing all ten affected segments, CNGT
requested a waiver permitting an alternative approach which they
believed would achieve both an equivalent level of safety in the
affected segments and internal inspection(s) that would evaluate the
163.19 mile transmission line. Because of its knowledge of the good
physical condition of this line as presented in Notice 1 (described
below), CNGT expected that its implementation of the provisions of
Alternative A would be less costly and would reduce the number of days
that the gas transmission line would be out of service. Nonetheless,
CNGT understood that if the physical condition of the line was found to
be less than anticipated, its implementation of the provisions of
Alternate B would be more costly than total compliance with the
hydrostatic testing requirements of 49 CFR 192.611(a). To provide
clarity and continuity, the provisions of Alternative A and Alternative
B are set out as they appeared in Notice 1:
Alternative A consists of the following:
(A) Conducting a close interval pipe-to-soil corrosion survey (CIS)
of the 163.19 mile line;
(A2) Hydrostatic testing four segments (totaling 4.96 miles). If no
leak occurs, or only a specified minor leak \1\ occurs and is
remediated, the hydrostatic testing is completed;
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\1\ Specified minor leak--A leak from valve packings, gaskets,
threaded fittings, or hydrostatic test equipment; and from localized
corrosion pitting on the 26-in line pipe.
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(A3) Inspecting the 163.19 mile line with a geometry pig followed
by a high resolution ``smart pig.'' Any defects impacting the MAOP are
promptly remediated. All defects detected by the ``smart pig'' are
cross-referenced with the CIS to correct any deficiencies in the
cathodic protection system, all before October 19, 1996; and
(A4) Inspecting the 163.19 mile line with a geometry pig followed
by a high resolution ``smart pig'' remediation of any defects impacting
the MAOP, all in the year 2001.
Alternative B would be performed only if, during the implementation
of (A2), a leak other than a specified minor leak \2\ occurs.
Alternative B consists of the following:
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\2\ Other than a specified minor leak--A leak from a crack,
crack-like defects, general corrosion, or from any other source
(except localized corrosion pitting) on the 26-inch line pipe.
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(B1) If a leak, other than a specified minor leak occurs during
(A2) and is remediated, the hydrostatic testing of the four segments is
completed;
(B2) Inspecting the 163.19 mile line with a geometry pig following
by a high resolution ``smart pig.'' Any defects impacting the MAOP are
promptly remediated. All before October 19, 1996; and
(B3) The period to qualify the MAOP is extended until (B3) is
completed. All defects detected by the ``smart pig'' are cross-
referenced with the CIS to correct any deficiencies in the cathodic
protection system. Hydrostatic testing and remediation of any leaks
occurring in the remaining six segments (totaling 5.95 miles), all
before June 30, 1997.
Basis for the Alternative Approach
CNGT's proposed alternative approach is based on their contention
that this transmission line is in good physical condition. In its
petition (and set out under this same heading in Notice 1), CNGT
supported that assertion by providing comprehensive information on the
transmission line's construction, operation, and maintenance history.
Furthermore, CNGT expressed confidence in the good physical
condition of this 26-inch diameter line by agreeing to the potential
consequences (during the implementation of Alternative A) of any leak
other than a specified minor leak during the hydrostatic testing of
(A2); because, such a leak would trigger the need to implement the more
costly and time consuming Alternative B. In such a case, under the
provisions of (B1) and (B3), CNGT would hydrostatically test all ten
segments as required by Sec. 192.611(a). Moreover, under (B2), they
would inspect the 163.19 mile transmission line with a geometry pig and
with a high resolution ``smart pig.''
RSPA Review
Our review of the petition showed the following:
(1) CNGT's contention that this 26-inch diameter transmission line
is in good physical condition was well supported with information on
the submerged-arc welded pipe, internal and external coatings, cathodic
protection, and (apart from one third party dig-in) the transmission
line's outstanding leak free record;
(2) During the period 1990 through 1996, the MAOP of six such
segments in this line were requalified by hydrostatic testing without a
leak or failure;
(3) The requirements of Sec. 192.611(a) for requalification would
be only partially waived during (A2), because four of the ten segments
(representing 4.96 miles or a 45.46% sampling of the total 10.91 miles)
would be hydrostatically tested;
(4) If a leak, other than a specified minor leak occurs during the
hydrostatic testing of (A2), then under (B1) the leak is remediated and
under (B3) the remaining six segments would be hydrostatically tested
before June 30, 1997. This would (with the extension of the 18-month
period in Sec. 192.611(c)) result in total compliance with
Sec. 192.611(a). Additionally, during (B2) there would be an internal
inspection of the 163.19 mile transmission line during 1996;
(5) If no leak occurred, or only a specified minor leak occurred,
under (A3) the complete transmission line would be internally inspected
during 1996 and under (A4) internally inspected again during the year
2001;
(6) The implementation of either (A3) or (B2), the ``smart pig''
inspection in 1996, would be the first time the 26-inch diameter line
has been inspected by a ``smart pig.'' A ``smart pig'' is capable of
detecting certain flaws in the pipe wall that (when interpreted) may
disclose defects that jeopardize the safe operation of the gas
transmission line . CNGT would run a ``smart pig'' of the high
resolution type, which is considered to be state-of-the-art technology
for the identification of pipe wall defects;
(7) Defects detected by the ``smart pigs'' would be cross-
referenced with the close interval pipe-to-soil corrosion survey to
correct any deficiencies in the cathodic protection system; and
(8) The ``smart pig'' runs would be preceded by a geometry pig that
is capable of detecting dents in the pipe wall and girth welds.
Notice 1
In response to the CNGT's petition and the justification it
contained, RSPA issued a Notice of petition for waiver inviting persons
to submit written comments, (Notice 1) (61 FR 35860; July 8, 1996). In
that notice, RSPA explained why neither the implementation of Alternate
A nor its backup, Alternate B, would be inconsistent with pipeline
safety. In fact, we saw the implementation of either alternative as
contributing to the safety of the 163.19 mile transmission line.
[[Page 50902]]
Discussion of Comments
RSPA received public comments on Notice 1 from six gas pipeline
operators and one pipeline related trade association. All seven
commenters endorsed the alternative approach proposed by the petitioner
and believed that the plan of action would ensure pipeline safety. Two
pipeline operators stated that ``CNGT's proposal appears to be an
excellent implementation of RSPA's proposed implementation of Risk
Based Pipeline Operations procedures.''
Action on Petition
In accordance with the foregoing and by this order, RSPA finds that
the requested waiver would not be inconsistent with pipeline safety.
However, if during the hydrostatic testing required under Alternative
A, a leak other than a specified minor leak occurs, CNGT is required to
implement Alternative B. Accordingly, CNGT's petition for waiver from
compliance with the requirements of 49 CFR 192.611(a) is granted under
the provisions set out in Alternate A and Alternate B (above) under the
heading Alternate Approach.
Issued in Washington, DC on September 24, 1996.
Richard B. Felder,
Associate Administrator for Pipeline Safety.
[FR Doc. 96-24863 Filed 9-26-96; 8:45 am]
BILLING CODE 4910-60-P
