Main line failure resulted from combination of minor causes
- NOVA Corp. of Alberta, Calgary (Canada)
Combined effects of a preexisting weld defect, settlement of adjacent branch piping, and less than critical line pressure caused the rupture and fire Jan. 8, 1992, on the Western Alberta main line. The subsequent metallurgical investigation concluded that the rupture originated at a pre-existing hydrogen crack located at the toe of a hot-tap stub weld on the 36-in. carrier pipe. Brittle fracture propagation in both directions from the tee resulted in a rupture length of approximately 1,225 ft. Crack propagation was consistent with properties of the 1960s vintage 36-in. pipe material which had met American Petroleum Institute (API) requirements at installation. Fracture analysis showed that all three conditions -- weld defect, piping settlement, and line pressure -- were necessary for the failure to occur. The failure pressure was in fact less than the maximum allowable operating pressure (MAOP). The paper describes the failure.
- OSTI ID:
- 7207882
- Journal Information:
- Oil and Gas Journal; (United States), Journal Name: Oil and Gas Journal; (United States) Vol. 92:12; ISSN 0030-1388; ISSN OIGJAV
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
030500* -- Natural Gas-- Health & Safety
032000 -- Natural Gas-- Transport
Handling
& Storage
ACCIDENTS
ALBERTA
CANADA
DEFECTS
DEVELOPED COUNTRIES
FAILURE MODE ANALYSIS
FAILURES
FRACTOGRAPHY
FRACTURE PROPERTIES
GROUND SUBSIDENCE
HARDNESS
JOINTS
MECHANICAL PROPERTIES
METALLURGY
MICROHARDNESS
NORTH AMERICA
PIPELINES
PRESSURE DEPENDENCE
RUPTURES
STRESS ANALYSIS
SYSTEM FAILURE ANALYSIS
SYSTEMS ANALYSIS
WELDED JOINTS