[Federal Register Volume 61, Number 131 (Monday, July 8, 1996)]
[Notices]
[Pages 35860-35861]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-17300]
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DEPARTMENT OF TRANSPORTATION
Research and Special Programs Administration
[Docket No. P-96-8W; Notice 1]
CNG Transmission Company; Petition for Waiver
AGENCY: Research and Special Programs Administration, DOT.
ACTION: Notice of petition for waiver.
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SUMMARY: CNG Transmission Company (CNGT) has petitioned the Research
and Special Programs Administration (RSPA) for a waiver from compliance
with provisions of 49 CFR 192.611(a) requiring confirmation of the
maximum allowable operating pressure (MAOP) by hydrostatic testing.
Instead, CNGT requests they be permitted to requalify the MAOP by an
alternative approach involving a combination of hydrostatic testing and
inspection by an instrumented internal inspection device commonly known
as a ``smart pig''. The need to confirm the MAOP results from a recent
increase in the population density along certain segments of a 26-inch
diameter gas transmission line in Ohio.
DATES: Written comments submitted in duplicate must be received on or
before August 7, 1996. Interested persons should submit as part of
their written comments all the material that is considered relevant to
any statement of fact or argument made.
ADDRESSES: Comments may be mailed or hand delivered to the Dockets Unit
[DHM-20], Room 8421, Research and Special Programs Administration, U.S.
Department of Transportation, 400 Seventh St., SW., Washington, DC
20590-0001. Comments should specify the Docket No. stated in the
heading of this document; the original and two copies should be
submitted. Dockets may be reviewed and copied between the hours of 8:30
a.m. and 4:30 p.m., Monday through Friday, except Federal holidays.
FOR FURTHER INFORMATION CONTACT: Albert C. Garnett, (202) 366-2036,
Office of Pipeline Safety, regarding the subject matter of this notice
or the Dockets Unit, (202) 366-5046, for copies of this notice or other
materials in the docket.
SUPPLEMENTARY INFORMATION:
Background
By correspondence dated April 23, 1996, CNGT requested a waiver
from compliance with the MAOP confirmation or revision provisions of 49
CFR 192.611(a) for pipeline segments where the hoop stress
corresponding to the established MAOP is not commensurate with the
present class location. The requested waiver applies to ten segments
(totaling 10.91 miles) and located on CNGT's transmission line TL-400.
Transmission line TL-400 begins at the Lebanon Compressor Station
in Warren County, Ohio, and transports gas eastward to the Gilmore
Compressor station in Tuscarawas County, Ohio, a distance of 163.19
miles. The 26-inch diameter transmission line was designed and tested
to operate at an MAOP of 850 psig.
The ten line segments that are the subject of this waiver request
operate at a hoop stress of greater than 40% of the specified minimum
yield strength (SMYS) and are located in areas where a recent increase
in population indicated a change in their class location. Accordingly,
CNGT complied with the provisions of Sec. 192.609 and completed a study
of the subject segments to determine: (a) their present class location;
(b) a comparison of their original design, construction, and testing
procedures with the provisions required for their present class
location; (c) their physical condition ascertained from available
records; (d) their operating and maintenance history; (e) their maximum
actual operating pressure and corresponding operating hoop stress; and
(f) the extent of the area affected by the population increase and
other factors which may limit further expansion of the more densely
populated area.
CNGT determined from the study required by Sec. 192.609 (a) and (f)
that the recent expansion of the population density had changed the
subject segments from Class 1 locations to Class 2 locations. CNGT also
determined from the study required by Sec. 192.609 (b)-(e) that the ten
segments were in good physical condition. Consequently, in accordance
with the provisions of Sec. 192.611 (a) and (c), CNGT must confirm or
revise the originally established MAOP (850 psig) within the 18-month
period ending October 19, 1996.
The hydrostatic test which established the MAOP at 850 psig was
performed at a pressure of 953 psig, although a test pressure of 935
psig would have been sufficient under the provisions of
Sec. 192.619(a)(2)(ii). After October 19, 1996, these segments may not
be operated at an MAOP above 762 psig (a reduction of 88 psig) due to
their reclassification as Class 2 locations. However, CNGT seeks to
maintain the MAOP at 850 psig in order to meet their gas delivery
commitments. Consequently, requalification by hydrostatic testing to a
minimum pressure of 1,063 psig would be in accordance with
Sec. 192.611(a)(3).
TL-400 is a single long transmission line that transports gas from
third parties to local distribution companies and to underground
storage facilities. CNGT states that it would be unreasonable to reduce
the MAOP and thereby lose gas throughput that would prevent them from
meeting their contractual obligations. CNGT also asserts that
hydrostatically testing all ten segments would require the line to be
taken out of service for a minimum of 16 days. Additionally, CNGT
asserts that the acquisition and disposal of the water used in the
hydrostatic testing would be burdensome.
Alternative Approach
Instead of hydrostatically testing all ten segments, CNGT requested
a waiver permitting an alternative approach which they believe would
achieve both an equivalent level of safety in the subject segments and
a complete evaluation of the 163.19 mile transmission line.
Additionally, CNGT expects the proposed approach to be considerably
less costly and to reduce the number of days that the transmission line
would be out of service.
CNGT's proposal consists of two alternatives supplemented by a work
plan (dated May 14, 1996). Although, not set out as such in the
petition, the alternatives are identified for the purposes of this
document as Alternative A and Alternative B:
Alternative A consists of the following:
(A1) 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 Sspecified 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
[[Page 35861]]
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'' and 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 followed
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 the contention
that this transmission line is in good physical condition. In the
petition, they supported that assertion by providing information on the
line's construction, operation, and maintenance history.
CNGT states that the 26-in diameter line is constructed of
submerged-arc welded steel pipe that has been joined by welding. The
pipe is internally coated with mill-applied liquid epoxy and externally
coated with mill-applied coal tar enamel. The line was hydrostatically
tested and commissioned in December 1968. Cathodic protection is
provided by impressed current remote groundbeds and assisted with
magnesium anode beds. CNGT states that the 21 test stations used to
monitor the level of cathodic protection in the subject segments do not
show any areas of low potential. CNGT states that, aside from one
failure in 1981 due to third party damage, no other leaks have occurred
since the line has been in service. Moreover, during the period 1990
through 1996, the MAOP of six other such segments in this line were
requalified by hydrostatic testing under Sec. 192.611(a) without a leak
or failure.
The proposed alternative approach expresses the petitioner's
confidence that the line is in good physical condition. Any leak other
than a specified minor leak occurring during the hydrostatic testing of
(A2) would trigger the requirement to implement the more costly and
time consuming Alternative B. Under (B1) and (B3), CNGT would need to
hydrostatically test all ten segments required by Sec. 192.611(a).
Moreover, under (B2), they would need to inspect the 163.19 mile line
with a geometry pig and with a high resolution ``smart pig.''
RSPA Response
Our review of the petition for waiver showed the following:
(1) CNGT's contention that this particular line is in good physical
condition is well supported with information on the pipe, internal and
external coatings, cathodic protection, and the transmission line's
outstanding leak record;
(2) The provisions 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;
(3) If a leak, other than a specified minor leak occurs during the
hydrostatic testing of (A2), then under (B3) the remaining six segments
would be hydrostatically tested. This would result in compliance with
Sec. 192.611(a). Additionally, during (B2) there would be an internal
inspection of the complete 163.19 mile transmission line;
(4) Otherwise, during (A3) and (A4), the complete transmission line
would be internally inspected during 1996 and internally inspected
again during the year 2001;
(5) The implementation of either (A3) or (B2) ( the in-line
inspection in 1996) would be the first time transmission line TL-400
has been inspected by a ``smart-pig;'' and
(6) 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.
In view of the foregoing, it appears that neither Alternative A nor
its back up, Alternative B, would be inconsistent with pipeline safety.
Instead, we see the implementation of either alternative as
contributing to the safety of this 163.19 mile transmission line.
Consequently, RSPA proposes to grant the waiver.
Interested persons are invited to comment on the proposed waiver by
submitting their views or arguments with supporting data, if available,
in the manner described under the heading ADDRESSES (above). All
comments received before the date shown under DATES (above) will be
considered before final action is taken. Late filed comments will be
considered as far as practicable. No public hearing is contemplated,
but one may be held at a time and place set in a notice in the Federal
Register if requested by an interested person desiring to comment at a
public hearing and raising a genuine issue.
Authority: 49 U.S.C. 60118(c); and 49 CFR 1.53.
Issued in Washington, DC, on July 2, 1996.
Richard B. Felder,
Associate Administrator for Pipeline Safety.
[FR Doc. 96-17300 Filed 7-5-96; 8:45 am]
BILLING CODE 4910-60-P
