Case
Studies in Engineering Failure Analysis, Available online 11 October 2013, In
Press, Accepted Manuscript Open Access
Analysis
of a corrosion under insulation failure in a carbon steel refinery hydrocarbon
line
W. Geary,
Health and Safety Laboratory, Harpur Hill Buxton Derbyshire, UK, SK17 9JN
Abstract
The
catastrophic failure of an insulated 210 mm internal diameter pipe carrying
hydrocarbons led to an explosion and fire at a refinery facility, the
evacuation of the site and to millions of pounds worth of damage to a process
vessel and associated plant. The investigation showed that the failure had
occurred as a result of a corrosion under insulation (CUI) mechanism.
Water had entered the insulation system through a breach in the
jacketing, made to accommodate a walkway support bracket. No adequate
precautions had been made to weather-proof the insulation following the
penetration of the jacket/insulation system.
Water, contaminated with sodium chloride and other pollutants, had migrated
through the insulation and along the interface between the insulation and the
pipe, forming a pool at the lowest point. The zinc and silicone acrylic pipe
coating system had been consumed and corrosion of the carbon steel substrate
had occurred at a rate consistent with published data.
The underlying causes of failure were identified as: a) a lack of adequate
management controls over the insulation installation process and b), the lack
of an adequate inspection regime to identify CUI in the period between
installation and failure.
The incident resulted in heightened awareness of CUI issues on major hazard
plant and increased regulator focus on this issue in all areas of ageing plant.
Free Full Text Source: http://www.sciencedirect.com/science/article/pii/S2213290213000448
No comments:
Post a Comment