Maintenance planning under imperfect inspections of corroded pipelines

Abstract In this paper, a maintenance policy is proposed for pipelines subject to corrosion, by taking into account imperfect inspection results. The degradation of the pipeline is induced by uniform and pitting corrosion, leading to losses in the pipe wall thickness. The inspection is applied to detect the corrosion defects, namely the corrosion depth and width. The inspection has a detection threshold under which no corrosion can be measured. Due to uncertainties, each inspection is affected by the probability of detecting small defects and the probability of wrong assessment in terms of defect existence and size. The present work aims at integrating imperfect inspection results in the cost model for corroded pipelines, where the failure probabilities are computed by reliability methods. A numerical application on a gas pipe shows the influence of inspection quality and cost on the choice of the optimal maintenance planning.

[1]  Daniel Straub,et al.  Risk based inspection planning for structural systems , 2005 .

[2]  Franck Schoefs,et al.  Development of a two-stage inspection process for the assessment of deteriorating infrastructure , 2010, Reliab. Eng. Syst. Saf..

[3]  Robert E. Melchers,et al.  Statistical Characterization of Pitting Corrosion—Part 1: Data Analysis , 2005 .

[4]  Christofer Leygraf.  Atmospheric corrosion , 2000 .

[5]  Daniel Straub,et al.  Unified Approach to Risk-Based Inspection Planning for Offshore Production Facilities , 2003 .

[6]  Robert E. Melchers,et al.  Reliability estimation of pressurised pipelines subject to localised corrosion defects , 1996 .

[7]  Yan-Gang Zhao,et al.  A general procedure for first/second-order reliabilitymethod (FORM/SORM) , 1999 .

[8]  J. Kiefner,et al.  Failure Stress Levels of Flaws in Pressurized Cylinders , 1973 .

[9]  Daniel Straub,et al.  Risk-Based Inspection Planning of Offshore Installations , 2002 .

[10]  J. F. Kiefner,et al.  DUCTILE FRACTURE INITIATION, PROPAGATION, AND ARREST IN CYLINDRICAL VESSELS , 1972 .

[11]  M. Ahammed,et al.  Probabilistic estimation of remaining life of a pipeline in the presence of active corrosion defects , 1998 .

[12]  Henrik O. Madsen,et al.  Structural Reliability Methods , 1996 .

[13]  Franck Schoefs,et al.  Probabilistic modeling of inspection results for offshore structures , 2003 .

[14]  John Dalsgaard Sørensen,et al.  Optimal Inspection Planning for Fatigue Damage of Offshore Structures , 1990 .

[15]  Djamil Aïssani,et al.  Impact of few failure data on the opportunistic replacement policy for multi-component systems , 2010, Reliab. Eng. Syst. Saf..

[16]  Alaa Chateauneuf,et al.  Opportunistic policy for optimal preventive maintenance of a multi-component system in continuous operating units , 2009, Comput. Chem. Eng..

[17]  Michael Havbro Faber,et al.  Simplified and Generic Risk Based Inspection Planning , 2000 .

[18]  Kamel Chaoui,et al.  Reliability assessment of underground pipelines under the combined effect of active corrosion and residual stress , 2006 .

[19]  Alaa Chateauneuf,et al.  Reliability-based assessment of polyethylene pipe creep lifetime , 2007 .

[20]  Han Ping Hong,et al.  Inspection and maintenance planning of pipeline under external corrosion considering generation of new defects , 1999 .

[21]  Daniel Straub,et al.  Computational Aspects of Risk-Based Inspection Planning , 2006, Comput. Aided Civ. Infrastructure Eng..

[22]  Daniel Straub,et al.  Modeling dependency in inspection performance , 2003 .

[23]  R. Melchers.  The effect of corrosion on the structural reliability of steel offshore structures , 2005 .

[24]  Vikram Pakrashi,et al.  ROC dependent event isolation method for image processing based assessment of corroded harbour structures , 2010 .

[25]  E. Castillo,et al.  Uncertainty analyses in fault trees and Bayesian networks using FORM/SORM methods , 1999 .

[26]  Robert E. Melchers,et al.  Probabilistic analysis of underground pipelines subject to combined stresses and corrosion , 1997 .

[27]  Markus Niffenegger,et al.  Probabilistic analysis of pipelines with corrosion defects by using FITNET FFS procedure , 2011 .

[28]  Michael Havbro Faber,et al.  Optimal inspection and repair planning: Case studies using IMREL software , 1994 .