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10 September 2007
Pipeline Damage at Gräveneck Assessment Report
Seite 2 Leitungsschaden Gräv eneck - Sachstandsbericht September 2007 TU CMy /Leu
Contents
1. Key Figures of E.ON Ruhrgas AG
2. Information on the Course of the Damage
3. Status of Investigations
4. Likely Cause of Damage
5. Pipeline Safety Measures
Seite 3 Leitungsschaden Gräv eneck - Sachstandsbericht September 2007 TU CMy /Leu
Key Figures of E.ON Ruhrgas AG
existing pipeline
underground storage facility
compressor station
field station
gas import point
S 426c
Gräveneck
Pipeline system
owned / partly owned by E.ON Ruhrgas and project companies 11,273 km managed by E.ON Ruhrgas 12,690 km Compressor stations managed by E.ON Ruhrgas 28 stations 90 units 853 MW Underground storage facilities
used by E.ON Ruhrgas 11 storage facilities 5.1 bn m³ of working gas
Essen
Berlin
Cologne
Saarbrücken
Frankfurt/ Main
Zw ickau
Hanover
Emden
Hamburg
Flens- burg
Waidhaus
Nürnberg
Passau
Munich
Stuttgart
Freiburg
Leipzig
Dresden
Seite 4 Leitungsschaden Gräv eneck - Sachstandsbericht September 2007 TU CMy /Leu
Information on the Course of the Damage Location of Damage in the Field
Pipeline Scheidt-Wetzlar Pipeline No. 022/019/000
Nominal diameter DN 600 Nominal pressure PN 67,5
Year built 1977 Pressure at time of rupture appr. 51
bar Material STE 480.7 TM Coating PE
Seite 5 Leitungsschaden Gräv eneck - Sachstandsbericht September 2007 TU CMy /Leu
Course of Events on 28 August 2007
Natural gas escapes, ignites and bursts into flame with loud noise.
Alarm is raised at central control room in Essen; gas flow into pipeline at Scheidt is immediately stopped
Immediate isolation of the relevant pipeline section stops gas flame
Fire in surrounding area is extinguished by fire brigade
Damage to houses, forest, railway track
Some local residents undergo medical examinations as a precaution
Event causes considerable emotional strain on local residents
Seite 6 Leitungsschaden Gräv eneck - Sachstandsbericht September 2007 TU CMy /Leu
Impressions from Damage Site
Seite 7 Leitungsschaden Gräv eneck - Sachstandsbericht September 2007 TU CMy /Leu
Detailed Course of Events
10:05 a.m. Pressure loss on pipeline 22/19
10:07 a.m. Alarm raised in responsible Operations Areas
10:15 a.m. Police arrives at site, followed by arrival of fire brigade
10:23 a.m. Initial information given by responsible operations officer (Betriebsmeister) at site
10:36 a.m. Information about isolated pipeline section received at reporting centre (ZMS)
10:50 a.m. Gas flame stopped and fire in immediate vicinity extinguished
Seite 8 Leitungsschaden Gräv eneck - Sachstandsbericht September 2007 TU CMy /Leu
Status of Investigations
The pipeline was in a faultless condition; its integrity had been confirmed
There was no corrosion / reduction of the pipe wall thickness
The cathodic protection system was working properly
The joint welds were tested during construction and found to be faultless
A stress test was carried out
An intelligent pig run (internal inspection) showed nothing unusual in this area
The documentation is complete (material test certificates, pipe log, etc.)
Seite 9 Leitungsschaden Gräv eneck - Sachstandsbericht September 2007 TU CMy /Leu
Likely Cause of Damage
The likely cause of the damage is the soil pressure on the slope, at the bottom of which the pipeline is located.
As result of the heavy rains and the high ground water level, the soil at the bottom of the slope had softened.
The open pipe trench for the parallel Lauterbach-to-Scheidt pipeline, which is under construction, further reduced the stability of the slope.
Moreover, the excavated material (which had been stored above the pipeline in service) further reduced the stability of the slope.
These influences caused the pipeline to be displaced by some 2 m from its original position, leading to a failure of a girth weld between a bend and a straight pipe.
Detailed material tests by the Competence Centre and independent experts are currently under way.
Seite 10 Leitungsschaden Gräv eneck - Sachstandsbericht September 2007 TU CMy /Leu
Likely Damage Factors
solid rock
slope loam
high flood loam
Aushubmaterial
Lauterbach-to-Scheidt pipeline
Scheidt-to-Weidenhausen
pipeline
water /
inundation
pipe trench
load exerted by excavated
material
Seite 11 Leitungsschaden Gräv eneck - Sachstandsbericht September 2007 TU CMy /Leu
Pipe Displacement
2.07 m
point of damage
original position
Seite 12 Leitungsschaden Gräv eneck - Sachstandsbericht September 2007 TU CMy /Leu
Construction of Natural Gas Transmission Pipelines
Material tests, workshop tests, material certificates
Stress testing
Intensive measurements (close interval surveys)
Pigging
TÜV certificate
Seite 13 Leitungsschaden Gräv eneck - Sachstandsbericht September 2007 TU CMy /Leu
Operation & Monitoring of Natural Gas Transmission Pipelines Pipeline protection
(coating, protective current)
Mobile and aerial surveys
Specialists, technicians and engineers Germany-wide
Central pipeline monitoring and Reporting Centre
Approved for operation in accordance with Energy Industry Act and applicable technical rules
Seite 14 Leitungsschaden Gräv eneck - Sachstandsbericht September 2007 TU CMy /Leu
BACK UP
Seite 15 Leitungsschaden Gräv eneck - Sachstandsbericht September 2007 TU CMy /Leu
Impressions from Damage Site
Seite 16 Leitungsschaden Gräv eneck - Sachstandsbericht September 2007 TU CMy /Leu
Measures to Remedy Pipeline Damage and Secure Gas Supply in the Area
Clear up site and and take safety precautions on slope
Remove damaged pipe parts (under the supervision of the State Office of Criminal Investigation)
Various activities by independent experts (TÜV, DVGW, soil experts)
Quickly restore of gas supply
Continue with construction work to ensure supply during winter
Seite 17 Leitungsschaden Gräv eneck - Sachstandsbericht September 2007 TU CMy /Leu
Four Delivery Points of SüWag and E.ON Mitte Affected by Isolation of Pipeline Section
SüWag
Stadtwerke Weilburg
E.ON Mitte
- Weinbach
- Gräveneck
Seite 18 Leitungsschaden Gräv eneck - Sachstandsbericht September 2007 TU CMy /Leu
Pressure Curve over Time at Weidenhausen (red) and Volume Flows into the Pipeline at Scheidt (black).
Seite 19 Leitungsschaden Gräv eneck - Sachstandsbericht September 2007 TU CMy /Leu
E.ON Ruhrgas and E.ON Gastransport
TSO
Hügelheim
Bierwang
Passau
Bamberg
Marburg
Werne
Essen
Hamburg
Hannover- Vinnhorst
Nürnberg
Weiden
Waid- haus
Regensburg
Epe
Breitbrunn
Scheidt
Berlin
Ummeln
Saarbrücken Natural gas pipelines
existing under design underground storage facility compressor station field site gas import point
Network length: approx. 13,000 km