Based on EN 16348 Standardised Integrity Assessment - Pa… · Pipeline Design & Safety Philosophy ... Stress Test = Hydrostatic Test close to yield strength to identify and eliminate

Pipeline Operation and Maintenance | 10.4.2014

25

Internal Company Standard

Basis for Assessment of Pipeline Integrity

Describes basic principles of pipeline

integrity

Describes methods and procedures for

assessment of pipeline condition

Describes type, extent and frequency of

testing and assessment

Contains assessment criteria and limit values

Describes possible mitigating measures.

Standardised Integrity Assessment

Company Standard

Basic Principles of Pipeline Integrity;

Rules and Procedures for Verification

of Technical Pipeline Integrity

Based on EN 16348


26 Integrity Risks

Corrosion by Interference

AC corrosion

DC stray current corrosion

General Corrosion

• Under shielding coatings

• Due to insufficient cp

• Within casings

• Under concrete saddles

Cracks

Stress corrosion cracking

…

Mechanical Damage

(Third party interference)

By trenching machines

Drilling

Dents

…

Milling defects

Material defects

Inclusions

Laminations

Rolling defect

Grindings

Routing and Strain

Pipeline displacement

Additional strain

Geometrical Defects

Expansions

Dents

Miscellaneous

Girth weld anomalies

Lightning puncture

…


27

1912 1958 1963 today Year of construction

Not piggable

Gas or electrically welded

Old pipe joints

Long operational period without CP

Not piggable

Electrically welded

CP almost since

construction

Piggable

(sections ≥ 20 km, > DN 200)

Electrically welded

CP since construction up to 1954 since 1955

Main Tool for

Integrity Assessment

Pipeline Classification for Integrity Assessment

Joint assessment (PIA2)

Intensive measurement

Casing survey


Casing survey

Inline Inspection

(Intelligent Pigging)

Not piggable

(e.g. sections < 20 km)

Electrically welded

CP since construction

Pipeline Category I Pipeline

Category II Pipeline Category III

Based on EN 16348


28

Integrity Assessment Process

Inline inspection

Measures (Repair, securing, refurbishment, replacement)

Priorisation and determination

of assessment method

Pipeline category I Sleeve sockets

1912 – 1958

Pipeline category II Not piggable

BJ 1959 - today

Pipeline category III piggable

1963 - today

High voltage assessment


Assessment and detail assessment (corrosion protection, materials)

0,0

0,2

0,4

0,6

0,8

1,0

1,2

1,4

1,6

1,8

Ltg 15 Ltg 7 Ltg 6 Ltg 1 Ltg 9 Ltg 5 Ltg 2

Hauptleitung inkl. Anschlüssen

Sch

ad

en

szah

l p

ro J

ah

r &

100 k

m

Assessm. of casing pipes

Sleeve sockets (PIA²)

Verification of Pipeline Integrity (Documentation, definition of expiry date)

Based on EN 16348


29

Integrity Measures and Intervals

Integrity Measure or Element Interval Reference

As-built documentation once G 463

Pressure test / stress test once G 463

Verification of CP effectiveness (e.g. by intensive measurement) once GW 10

Check of pressure safeguarding every four years G 495

CP remote monitoring every two months GW 10

Check of CP, off-potential measurements every three years GW 10

Check of AC interference situation every five years GW 10

Pipeline monitoring and maintenance (incl. tightness testing) Depending on

pipeline routing G 466-1

Valve functional testing annual G 466-1

Integrity assessment acc. to integrity

strategy (15 – 25 y)

G 466-1,

RN 210-001

Inline inspection acc. to ILI strategy

(15 – 25 y)

G 466-1,

RN 210-001

Assessment of old joints typically once RN 210-001

Strategy in the case of previous damage Case-by-case …

Excavation, NDT, check for corrosion, ... Case-by-case …

Integrity Assessment Tools

Contents

OGE at a Glance, OGE Pipelines in Germany

Integrated Management System

Pipeline Design & Safety Philosophy

Pipeline Integrity Management System

Corrosion Control

Hydrostatic and Tightness Testing

Inline Inspection Techniques

Defect and Failure Investigation

Troubleshooting & Repair-Techniques

Conclusions


30


31

CP-Tools/Methods and Intervals

CP-Tool / Method Example Reference Interval

Verification of cp effectiveness e.g. Intensive measurement GW 10 once

CP remote monitoring GW 16 2 month

Off-potantial measurement at

selected test stations GW 10 3 years

CP survey measurements

at casings GW 10, AfK 1 3 years

Review and check of AC

interference situation AfK 3, GL 718-079 5 years

Intensive measurement Integrity assessment G 466-1, RN 210-001 15 – 25 years 1

Intesive fault detection

Location of defects within

warranty period RN 268-022 (TVB)

Case by case AC corrosion assessment AfK 11

Verification of ILI features G 466-1, RN 210-001

Mobile cp probe Verification of cp effectiveness GW 10

Case by case Integrity assessment G 466-1, RN 210-001

Integrity Assessment Tools

1) Depending on condition of pipeline

DVGW G …

Corrosion Protection of Burried Pipelines

Burried pipelines are protected against corrosion by a combination of

electrochemical protection (cathodic corrosion protection) and an electrically insulating

coating (passive corrosion protection).

Cathodic Protection (CP)

Coke Groundbed Reference electrode

Coated pipeline

Anode (+)

Transformer/ Rectifier

Negative drain (-)

Protective current

Coating defect

Test post

Test coupon

Power supply

Earthing strip

Decoupling device

+ -

Passive Corrosion Protection

32


EN 12954, DVGW GW 12

Prerequesites for Installation of CP (EN 12954, GW12)

Electrical separation from grounded installations

(e.g. Metering- and compressor stations, grounding systems, e-valves)

Use of unsulating couplings or flanges

Longitudinal electrical conductivity

fullfilled for continuously welded pipelines

Electrically insulating coating

factory and field coating of all installations

33


EN 12954, DVGW GW 12

Typical Corrosion Risks on Pipelines

Corrosion under disbonded coatings

Corrosion within

casings

Corrosion under concrete saddles

Corrosion due to insufficient CP

AC corrosion

34


Coating insulation test (at construction stage)

Drainage test (at construction stage)

Intensive defect detection survey (within warranty period)

Intensive measurement survey (existing pipelines)

Quality Assurance by Corrosion Protection Measurements

Main objective is to prevent coating defects

35


DVGW GW 12, GW 10, …

Intensive Measurement (CIPS + DCVG)

V

V

V

Cable connection

CP protected, coated pipeline

Coating defect

Reference electrode

Voltage

gradient

measurement

Uon, Uoff

Potential measurement

Uon , Uoff

e.g. >10m

e.g. 5 m

36


AfK No. 10 DVGW GW 27, EN 13509

Transformer/

Rectifier

Coating defect

Casing pipe Product pipe

Pipeline

Rmi > Ra,min CP is effecitve

Rmi < Ra,min Assessment not possible

Ra,min = Spread resistance of a

coating defect that can just be

protected

Rmi = Calculated spread resistance of

coating defects within the casing pipe

(AfK Recommendation No. 1)

Assessment of Casings (Resistance Comparison Method)

37


AfK No 1 DVGW GW 20

High-Voltage Interference

steel pipeline

coating fault

(AC-voltage) corrosion

high voltage line

coating

U AC U AC

High-voltage power line

Coating defect

with AC corrosion

Pipeline IAC

JAC

JAC

max. touch voltage

AC corrosion

Vo

ltag

e U

AC

Vo

ltag

e U

AC

Calculated

voltage without

grounding systems

Calculated

voltage with

grounding systems

Integrity Assessment Tools 38


AfK No. 3 DVGW GW 22

Development of a Third Party Interference

Detection System Additional Safety

Benefit:

Real-time identification of a damage (liability)

Increased level of safety

Potential for optimisation of survey cycles

„Hazard“ „Protection“

TPI detection by CP measurement technique

New approach for pipeline protection

against external damage

TGL

W, 39

Beyond DVGW GW …

The Idea

40


Beyond DVGW GW …

The Idea

41


Beyond DVGW GW …

Realtest 11.03.2009, Test Scenario

TestPipeline DN 300, Length 12 m

Test-

post

Gaspipeline

DN 1200

PN 100

42


Real Test

Test Pipeline before Backfilling

Minidigger

22 ton Chain Dredger

43


Beyond DVGW GW …

Real Tests

Test 2 Test 4

44


Beyond DVGW GW …

//Vessn121/RG0T0180/RG0T0180/TGL/Baggerschadenpraevention/Präsentationen/Echter Vorversuch/Minibagger/Schaden M2/M2.AVI

//Vessn121/RG0T0180/RG0T0180/TGL/Baggerschadenpraevention/Präsentationen/Echter Vorversuch/Kettenbagger/Schaden K4/K4.AVI

Contents

OGE at a Glance, OGE Pipelines in Germany

Integrated Management System

Pipeline Design & Safety Philosophy

Pipeline Integrity Management System

Corrosion Control

Hydrostatic and Tightness Testing

Inline Inspection Techniques

Defect and Failure Investigation

Troubleshooting & Repair-Techniques

Conclusions


45

MOP

Pressure test at min. 1.3 MOP

Time

Inte

rnal

pre

ssu

re Rt0.5 = 1.6 MOP

Stress Test = Hydrostatic Test close to yield strength to identify and

eliminate pipe with serious defects, e.g. weld defects, out of spec

material; but no minor defects (VDTÜV Working sheet No. 1060)

Stress Test 46


DVGW G 463

Mill Defects found by Stress Test (at / after Construction)

Overlapping from

Plate rolling

Inclusion & Lamination

47


DVGW G 463

Cracks & Gouges found by Stress Test (Rehabilitation)

External Interference

Fatigue Crack Girth Weld Defects

SCC

48


DVGW G 463

Documents

Based on EN 16348 Standardised Integrity Assessment - Pa… · Pipeline Design & Safety Philosophy ... Stress Test = Hydrostatic Test close to yield strength to identify and eliminate