L a n d e s u m w e l t a m t N o r d r h e i n – W e s t f a l e n Dr. Norbert Wiese Tel. 0201/ , Fax UNECE Workshop on the Prevention of Accidents of Gas Transmission Pipelines, 8-9 March 2006, The Hague Pipeline Accident in North Rhine-Westphalia, Germany

Dr. Norbert Wiese, Department: Plant Safety, Information Systems on Plants, Substances and Emissions Contents The pipeline The accident and it´s consequences Measures taken after the accident Findings of investigations Conclusions and initiated actions

Dr. Norbert Wiese, Department: Plant Safety, Information Systems on Plants, Substances and Emissions Contents

Dr. Norbert Wiese, Department: Plant Safety, Information Systems on Plants, Substances and Emissions Pipeline Data ethylene gas transmission DN 300 (D a = 316 mm, s = 7 mm) date of construction: 1939 p N = 20 bar; p op = 17 bar material: analogical St 35 1,5 m underground Regulation: German Ordinance on High Gas Pressure Pipelines (Gashochdruckleitungsverordnung) German Ordinance on Long-Distance Pipelines (Rohrfernleitungsverordnung)

Dr. Norbert Wiese, Department: Plant Safety, Information Systems on Plants, Substances and Emissions Pipeline Data

Dr. Norbert Wiese, Department: Plant Safety, Information Systems on Plants, Substances and Emissions Pipeline Data Requirements: impermeable and resistant to expected strain resistant to damage caused by mining activities protection against external influences and corrosion safety devices for protection against inadmissible increase of pressure monitoring and recording operating pressures recording loss of gas limiting release of gas

Dr. Norbert Wiese, Department: Plant Safety, Information Systems on Plants, Substances and Emissions Contents

Dr. Norbert Wiese, Department: Plant Safety, Information Systems on Plants, Substances and Emissions

The accident and it´s consequences : 14:00 h: leak and release of ethylene gas  cloud residents  fire brigade simultaneous: significant decrease of pressure  shut-down of sluice valves no ignition 15:30 h: release stopped 50 persons in the neighbourhood affected split, not cracked open completely

Dr. Norbert Wiese, Department: Plant Safety, Information Systems on Plants, Substances and Emissions Contents

Dr. Norbert Wiese, Department: Plant Safety, Information Systems on Plants, Substances and Emissions Measures taken after the accident 6 persons evacuated roads within a radius of 500 m closed purged with nitrogen  no ignition hazard maximum strain estimated stretching devices excavated relief cuts set sleeve sockets welded

Dr. Norbert Wiese, Department: Plant Safety, Information Systems on Plants, Substances and Emissions Contents

Dr. Norbert Wiese, Department: Plant Safety, Information Systems on Plants, Substances and Emissions Findings of investigations rupture without macroscopic deformation  brittle fracture split of 11 mm 50% of perimeter

Dr. Norbert Wiese, Department: Plant Safety, Information Systems on Plants, Substances and Emissions Findings of investigations hook connector enlarged coarse-grain inside the welded seam finest cuts on surface of welding deposit

Dr. Norbert Wiese, Department: Plant Safety, Information Systems on Plants, Substances and Emissions Findings of investigations rupture in coarse-grain zone near heat affected zone coarse-grain development and local increase of hardness no relevant corrosion no indication to any enlarging due to inadmissible increase of pressure inconspicuous measurement of wall thickness

Dr. Norbert Wiese, Department: Plant Safety, Information Systems on Plants, Substances and Emissions Findings of investigations regular plant management and maintenance no necessity of mining safety measures due to previous informations –no specified mining region –less number of stretching devices hook connector accordant state of the art (1939) But: distinctly measurable bending and axial tensions outside the region of damage

Dr. Norbert Wiese, Department: Plant Safety, Information Systems on Plants, Substances and Emissions Contents

Dr. Norbert Wiese, Department: Plant Safety, Information Systems on Plants, Substances and Emissions Conclusions no inadmissible increase of pressure material sufficient resistant without any indications to deterioration spontaneous failure due to forces from outside the pipeline –damage done by mining? –geotectonics? –..... ? Cause ?

Dr. Norbert Wiese, Department: Plant Safety, Information Systems on Plants, Substances and Emissions Initiated actions setting of further relief cuts welding of sleeve sockets for relief –Pipeline without tension setting of resistance strain gauges Check-up of distances of stretching devices geodetic measurements

Dr. Norbert Wiese, Department: Plant Safety, Information Systems on Plants, Substances and Emissions Conclusions and initiated actions Question: If former mining activities cannot be excluded definitely: Is it necessary to take hazards from mining activities into account in any case irrespective of specified former mining region or not?

Dr. Norbert Wiese, Department: Plant Safety, Information Systems on Plants, Substances and Emissions Thank you for your attention !