1

Direct Assessment

Alan Eastman, PG&EDebbie DiMeo, Northeast Gas Association

OPS Public Meeting April 25, 2003

2

Key Points in Docket Submittal

DA is an effective method for detecting time dependent defects.Baseline and re-assessment schedules for DA must align with schedules for ILI and pressure testing.NACE RP 0502-2002 (ECDA) must be incorporated by reference. Remediation provisions need to be consistent with existing industry standards (B31.8S, RSTRENG)Industry supports Confirmatory DA.Direct Examination of 100% of the pipe (such as for above groundpiping) supports reinspection schedules to be established in the same manner as ILI.RSPA must be involved in DA continuous improvement/best practiceefforts planned in 2003.

3

NYS Direct Assessment Process Validation Project

Debbie DiMeo, Director, Plans and OperationsNortheast Gas AssociationOPS PLI Public Meeting April 25, 2003

ddimeo@northeastgas.org

4

NYS DA Process Validation Project Objectives

Demonstrate:

ECDA can be used to assess pipeline integrity with respect to locating areas containing external corrosion, coating flaws and third party damage.

ECDA is a valid pipeline integrity alternative to in-line inspection and pressure testing.

5

Key Elements of NYSDA Project

DA process consistent with the NACE ECDA TG041 Standard to validate DA

DA process applied in a uniform and structured manner across NYS

PSC staff as a project partner

Industry expert – objective third party

6

Technical BasisNine NGA members performed ECDA on ~2-mile segments (total 20 miles)

Utilized indirect survey tools and selected locations on pipe predicted to have indications and non-indications (ie, controls)

Excavated and assessed ECDA indications and non-indications

Compared predictions to excavation results

Performed statistical analysis

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Results of ~20 Miles of ECDA66 excavations

43 indications 40 locations with coating flaws

11 corrosion damage2 third party damage

3 no damage23 controls

22 no damage1 coating flaw

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Statistical ResultsProbability of finding an anomaly at an indication is 98%

Probability of not finding an anomaly at a control is 88%

Odds ratio of finding an anomaly at indication vs. control is 300 to 1

Indications statistically different from controls

Probability of finding a coating anomaly increases with holiday size ~99% for >5 in2

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Overall observation

Data collected supports DA in finding:

CP inadequaciesCoating flawsExternal corrosionLatent third party damageSubcritical flaws

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ConclusionsData collected supports ECDA as a valid integrity management tool

DA on par with ILI and pressure testing

Technical capability by member companies to perform DA

Members/NYS PSC comfortable with project and DA process

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Next Steps

Continue collecting ECDA data to add to database

Test new DA survey tools

Perform ICDA

Funding approved; work scope being refined

12

Overview of PG&E Work

Over the last 5 years have been working to formalize ECDA practicesIncluded a Demonstration Project in California where many Operators and Federal and State Regulators participatedDevelopment of a comprehensive ECDA Procedure (complies with RP0502)Established necessary protocolsApplied to pipelines in all class locationsComparison of 100 miles of ECDA data with same 100 miles of ILI dataContinue participation in industry Best Practice efforts

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200

300

400

500

600

700

800

900

1000

P/S

Pote

ntia

l (-m

V)

OnOffCriteria

Identification & Classification of Indications

CIS CriteriaSevere

CIS < 600 mV off,On/Off converge, >200 mV Depression

ModerateCIS < 600 mV offOn/Off don’t converge<200 mV Depression

MinorCIS between 600 & 850 mV off

200

300

400

500

600

700

800

900

P/S

Pote

ntia

l (-m

V)

OnOffCriteria

300

400

500

600

700

800

900

1000P/

S Po

tent

ial (

-mV)

OnOffCriteria

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Prioritization Criteria/Integration ProtocolPrioritization Criteria/Integration Protocol

CIS xx

Severe Moderate Minor NI

Severe I S S M Moderate I S M NI Minor I S M NI PC

M

NI I S M NI Severe I S S M Moderate I S M M Minor I S M NI D

CVG

NI S M M NI

I = ImmediateI = ImmediateS = ScheduledS = ScheduledM = MonitoredM = MonitoredNI = No IndicationNI = No Indication

Line 300A Site Three…Demonstration ProjectPoor Condition

Direct Assessment SurveyPacific Gas & Electric

Line 300A - Section 1 - MP 428.56 to 446.96

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

23110.00 23111.00 23112.00 23113.00 23114.00 23115.00 23116.00 23117.00 23118.00 23119.00 23120.00

Station (100 x feet)

Pipe-

to-s

oil Po

tent

ial (-

Volts

)

P\S OFF P\S ON DCVG (mV) Soil Resistivity (ohm-cm) 0.850 Volts

Sheet 50 of 97Profile A1

286MP 437.69

1464

225 250 200

Pipe Line Marker, FenceOverhead ACTest Station

200 100 275 310 350 45

4587

90 120

125 310

20 35 25 45 35 18

Brow ns Valley Rectifier

Excavate 10 ft.Excavate 10 ft.

Excavated, removed coating, sandblasted

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17

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A Contact Found During an ECDA

CATHODIC SURVEY 22/16-INCHGLENWOOD TO EGC

CIS AND PCM SURVEYMH-12 TO MH-13 OLD WESTBURY RD.

ELLISON AVE.

0.05

0.25

0.45

0.65

0.85

1.05

1.25

1.45

1.65

1.85

2.05

2.25

2.45

LOCATION - FEET

ON - P /CuSO4 VOLTAGE

OFF - P /CuSO4 VOLTAGE

P CM SURVEY - AMP S

JERICHO TNPKE.

NORTHERN STATE PARKWA

ASBURY / ELLISON RECTIFIER

MH-13 DIRECTION OF PCM SURVEY

SOUTHMH-12 TO MH -13, OLD WES TBURY RD., ELLIS ON AVE.

6" DISTRIBUTION GAS MAIN CONTACTING TOP OF 16" FACILITY MAIN

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Direct Examination of ECDA Contact

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Offset for 1948 Distribution Main

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Opportunities to Participate in ECDA Efforts

NGA DA project in NY (~10

companies)

GTI/PRCI/OPS project

GTI/AGA, 5-10 case studies

PG&E DA work in CA

Indirect Exams:

May – Jun. 2003

July – Aug. 2003?

Jun. – Aug. 2003

July – Aug. 2003

Direct Exams:

Jun. – Aug. 2003

Aug. – Sep. 2003?

Aug. – Oct. 2003

Jan. – Mar. 2004

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Opportunities to Participate in ICDA Efforts

ICDA (Wet)GTI/PRCI/OPS/SoCal

Development

ICDA (Dry)GTI/PRCI/OPS/SoCal

Validation

ICDA (Dry)NGA

Demonstration

Assemble integrity data:

Feb. – Jul. 2003

Feb. – Jul. 2003

-

Prioritize corrosion likelihood/model development:

May – Sep. 2003

May – Dec. 2003

May – Aug. 2003

Data analysis: Sep. – Dec. 2003

Dec. – Mar. 2004

Aug. – Dec. 2003

2323

SummarySummaryPast DA validation results support DA is a valid Integrity Past DA validation results support DA is a valid Integrity Management Process, and supports schedules being the Management Process, and supports schedules being the same as those for ILI and same as those for ILI and HydrotestingHydrotestingPast DA results also support that DA provides additional Past DA results also support that DA provides additional value to the ongoing integrity of the pipe over and above value to the ongoing integrity of the pipe over and above ILI and ILI and HydrotestingHydrotestingThe NPRM should reference the NACE RP0502 The NPRM should reference the NACE RP0502 Remediation provisions need to be consistent with existing Remediation provisions need to be consistent with existing standardsstandardsAdditional data will be available before August to further Additional data will be available before August to further improve confidence and support DAimprove confidence and support DALots of opportunity to participate and continue improving Lots of opportunity to participate and continue improving the processthe process