Abstract
The deterioration of the condition of process plants assets has a major negative impact on the safety of its operation. Risk based integrity modeling provides a methodology to quantify the risks posed by an aging asset. This provides a means for the protection of human life, financial investment and the environmental damage from the consequences of its failures. This methodology is based on modeling the uncertainty in material degradations using probability distributions, known as priors. Using Bayes theorem, one may improve the prior distribution to obtain a posterior distribution using actual inspection data. Although the choice of priors is often subjective, a rational consensus can be achieved by judgmental studies and analyzing the generic data from the same or similar installations. The first part of this paper presents a framework for a risk based integrity modeling. This includes a methodology to select the prior distributions for the various types of corrosion degradation mechanisms, namely, the uniform, localized and erosion corrosion. Several statistical tests were conducted based on the data extracted from the literature to check which of the prior distributions follows data the best. Once the underlying distribution has been confirmed, one can estimate the parameters of the distributions. In the second part, the selected priors are tested and validated using actual plant inspection data obtained from existing assets in operation. It is found that uniform corrosion can be best described using 3P-Weibull and 3P-Lognormal distributions. Localized corrosion can be best described using Type1 extreme value and 3P-Weibull, while erosion corrosion can best be described using the 3P-Weibull, Type1 extreme value, or 3P-Lognormal distributions.
Similar content being viewed by others
References
Abdusalam M, Stanley JT (1992) Steady state models for erosion corrosion of feed water piping. Corrosion 48(7):587–799
Ahn SE, Park CS, Kim HM (2007) Hazard rate estimation of a mixture model with censored lifetimes. J Stoch Environ Res Risk Assess 21:711–716
Anghel CI, Lazer I (2005) Risk assessments for vessels affected by corrosion. Periodica Polytech Ser Chem Eng 48(2):103–118
Baker R, Christakos G (2007a) Revisiting prior distributions, part1: priors based on physical invariance principle. J Stoch Environ Res Risk Assess 21:427–434
Baker R, Christakos G (2007b) Revisiting prior distributions, part2: implications of the physical prior in maximum entropy analysis. J Stoch Environ Res Risk Assess 21:435–446
Bedford T, Cooke R (2001) Probabilistic risk analysis. Cambridge University Press, Cambridge
D’ Agostino RB, Stephens MA (1986) Goodness of fit techniques. Marcel Dekker, Inc., New York
Desjardins G (2002) Improved data quality opens way for predicting corrosion growth and severity. Pipeline Gas J 28–32
Dey PK (2004) Decision support for inspection and maintenance: a case study of oil pipelines. IEEE Trans Eng Manage 51(1):47–56
Dey PK, Gupta SS (2001) Risk based model aids selection of pipeline inspection, maintenance strategies. Oil Gas J 54–60
Faber MH (2002) Risk based inspection planning: the framework. Struct Eng Int 3:186–194
Frangopol DM, Kallen MJ, Noortwijk JM (2004) Probabilistic models for life-cycle performance of deteriorating structures: review and future directions. Progress Struct Eng Mater 6:197–212
Fujita M, Schall G, Rackwitz R (1989) Adaptive reliability based inspection strategies for structures subjects to fatigue. In: Proceedings of 5th ICOSSAR, San Francisco, vol 3, pp 1619–1626
Geary W (2002) Risk based inspection: a case study evaluation of offshore process plant. Report HSL/2000/20, Health and Safety Laboratory, Scheffield
Googan C, Ashworth V (1990) Management of corrosion risk. Collation of Technical Papers-1990’s, Global Corrosion Consultants Limited
Goyet J, Straub D, Faber MH (2002) Risk based inspection planning methodology and application to an offshore structure. Revue Francasie de Genie Civil (English Version) 6(3):489–503
Gumbel EJ (1958) Statistics of extremes. Columbia University Press, New York
Halder A, Mahadevan S (2000) Probability, reliability and statistical methods in engineering. Wiley, USA
HSE UK (2002) Guidelines for use of statistics for analysis of sample inspection of corrosion, Research Report 016, Prepared by TWI for Health and Safety Executive, Her Majesty’s Stationary Office, 2–16 Colegate, Notwich
Johnson RA (2005) Miller and Freund’s probability and statistics for engineers. Pearson Prentice Hall, Upper Saddle River
Jones DA (1996) Principles and prevention of corrosion. Prentice Hall, Inc. Simon and Schuster/A Viacom Company, Upper Saddle River
Kallen MJ (2002) Risk based inspection in the process and refining industry. Master’s Thesis, Faculty of Information Technology and Science, Technical University of Delft, Delft
Kallen MJ, Noortwijk JM (2005) Optimal maintenance decisions under imperfect inspection. Reliab Eng Syst Saf 90(2–3):177–185
Khan FI, Howard R (2007) Statistical approach to inspection planning and integrity assessment. Insight 49(1):26–36
Khan FI, Haddara MM, Bhattacharya SK (2006) Risk based integrity and inspection modeling (RBIIM) of process components/system. Risk Anal 26(1):203–221
Khan FI, Sadiq R, Haddara M (2004) Risk based inspection and maintenance: multi-attribute decision making with aggregative risk analysis. Trans IChemE Process Saf Environ Protect 86(B2):398–411
Koch GH, Brongers MPH, Thompson NG, Virmani YP, Payer JH (2001) Corrosion cost and preventive strategies in the United States. Report FHWA-RD–01-156, Federal Highway Administration, USA. Available online at http://www.corrosioncost.com
Kowaka M (1994) Introduction to life prediction of industrial plant materials. Application of extreme value statistical method for corrosion analysis. Allerton Press Inc., New York
Lawson K (2005) Pipeline corrosion risk analysis—an assessment of deterministic and probabilistic methods. Anti-Corrosion Methods Mater 52(1):03–10
Laycock PJ, Cottis RA, Scarf PA (1990) Extrapolation of extreme pit depths in space and time. J Electrochem Soc 137(1):64–69
Lotsberg I, Sigurdsson G, Wold PJ (1999) Probabilistic inspection planning of the Asgard A FPSO hull structure with respect to fatigue. In: Proceedings of 18th Offshore Mechanics and Arctic Engineering, Newfoundland, pp 259–266
Madsen HO, Sorensen JD, Olesen R (1989) Optimal inspection planning for fatigue damage of offshore structures. Proc 5th ICOSSAR 3:2099–2106
Mansfeld M (1987) Corrosion mechanisms. Marcel Dekker, Inc., New York
McLaughlan RG, Stuetz RM (2004) A field based study of ferrous metal corrosion in groundwater. Water Sci Technol 29(2):41–47
Melchers RE (2003a) Probabilistic models for corrosion in structural reliability assessment—Part 1: empirical models. Trans ASME 125:264–271
Melchers RE (2003b) Probabilistic models for corrosion in structural reliability assessment—Part 2: models based on mechanics. Trans ASME 125:272–280
Melchers RE (2005) Statistical characterization of pitting corrosion—Part 2: probabilistic modeling of maximum pit depth. Corrosion 61(8):766–777
Melchers RE (2006) Recent progress in the modeling of corrosion of structural steel immersed in seawaters. J Infrastruct Syst ASCE 154–162
Montgomery RL, Serratella C (2002) Risk based maintenance: a new vision for asset integrity management. Pressure Vessel Piping 444:151–165
Noortwijk JM, Phajm VG (1996) Optimal maintenance decisions for berm breakwaters. Struct Saf 19(4):293–309
Paik JK, Wang G, Thayamballi AK, Lee JM, Park Y (2003) Time dependent risk assessment of aging ships accounting for general/pitting corrosion, fatigue cracking and local denting damage. In: SNAME annual meeting in San Francisco, USA
Salama MM (2000) An alternative to API 14E erosional velocity limits for sand laden fluids. J Energy Resour Technol ASME 122:71–77
Sankaran KK, Perez R, Jata KV (2001) Effect of pitting corrosion on the fatigue behavior of aluminum alloy 7075-T6: modeling and experimental studies. Mater Sci Eng A297:223–229
Scarf PA, Laycock PJ (1996) Estimation of extremes in corrosion engineering. J Appl Stat 23(6):621–643
Skjong R (1985) Risk based optimization of inspection strategies. In: Proceedings of ICOSSAR 85, vol 3. Kobe, pp 614–618
Soares CG, Garbatov Y (1996) Reliability of maintained ship hulls subjected to corrosion. J Ship Res 40(3):235–243
Straub D (2004) Generic approaches to risk based inspection planning for steel structures, PhD Thesis, Swiss Federal Institute of Technology, Zurich
Straub D, Faber MH (2005) Reliability updating for structures subjects to localized corrosion defects. In: Augusti G, Schuller GI, Ciampoli M (eds) Proceedings of ICOSSAR. Millpress, Rotterdam
Tesfamariam S, Sadiq R (2008) Probabilistic risk analysis using ordered weighted averaging (OWA) operators. J Stoch Environ Res Risk Assess 22:01–15
Vinod G, Bidhar SK, Kushwaha HS, Verma AK, Srividya A (2003) A comprehensive framework for evaluation of piping reliability due to erosion-corrosion for risk informed in-service inspection. Reliab Eng Syst Saf 82:187–193
Willcocks J, Bai Y (2000) Risk based inspection and integrity management of pipeline systems. ISOPE 11:285–294
Acknowledgments
Authors gratefully acknowledge the financial support provided by Natural Science and Engineering Research Council (NSERC) and Inco Innovation Centre (IIC) HSE module. Furthermore, authors are thankful to Robert Howard and Lloyd’s Register EMEA for the continued support of this research.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Thodi, P., Khan, F. & Haddara, M. The selection of corrosion prior distributions for risk based integrity modeling. Stoch Environ Res Risk Assess 23, 793–809 (2009). https://doi.org/10.1007/s00477-008-0259-x
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00477-008-0259-x