Comparative Study between Degradation Analysis and First Order Reliability Method for Assessing Piping Reliability for Risk-Based Inspection

Abstract—Piping systems in refineries and petrochemical plants are exposed to corrosive environment causing various types of degradation mechanisms. One of the damage mechanisms experienced is gradual wall thinning that causes the pipe to leak. Since the piping systems carry hydrocarbons or other pr...

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Main Authors: Mokhtar, Ainul Akmar, che ismail, mokhtar, mohamad, masdi
Format: Citation Index Journal
Language:English
Published: 2009
Subjects:
Online Access:http://scholars.utp.edu.my/id/eprint/1767/
http://scholars.utp.edu.my/id/eprint/1767/1/Comparative_Study_between_Degradation_Analysis_and_First_Order_Reliability_Method_for_Assessing_Piping_Reliability_for_Risk-Based_Inspection.doc.pdf
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author Mokhtar, Ainul Akmar
che ismail, mokhtar
mohamad, masdi
author_facet Mokhtar, Ainul Akmar
che ismail, mokhtar
mohamad, masdi
author_sort Mokhtar, Ainul Akmar
building UTP Institutional Repository
collection Online Access
description Abstract—Piping systems in refineries and petrochemical plants are exposed to corrosive environment causing various types of degradation mechanisms. One of the damage mechanisms experienced is gradual wall thinning that causes the pipe to leak. Since the piping systems carry hydrocarbons or other process fluids, the presence of small leak may lead to a hazardous situation. Therefore, proper inspection and maintenance of these systems is essential for maintaining a safe and continuous operation. Risk-based inspection (RBI) strategy has been adopted to establish the inspection strategy for piping systems where the strategy is based on risk calculated. Risk is defined as the product of the probability of failure and its consequences of failure. Assessing the failure probability for piping systems in RBI approach typically follows the guideline by American Petroleum Institute (API 581) where the method is deterministic. This study explores the available probabilistic analysis techniques in estimating the piping failure probability, namely, degradation analysis and first-order reliability method (FORM). The objective of this paper is to estimate the pipes failure probability using these two techniques where both models require different input data. Degradation analysis only uses the pipe wall thickness data that are usually being collected during inspection for pipes subject to wall thinning. Conversely, FORM model requires data on material properties and physical geometric of the piping system to estimate the failure probability. The failure probability estimated by these two techniques are then compared and discussed. The results showed that the degradation analysis is more conservative compared to FORM.
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institution Universiti Teknologi Petronas
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spelling oai:scholars.utp.edu.my:17672017-03-20T02:00:01Z http://scholars.utp.edu.my/id/eprint/1767/ Comparative Study between Degradation Analysis and First Order Reliability Method for Assessing Piping Reliability for Risk-Based Inspection Mokhtar, Ainul Akmar che ismail, mokhtar mohamad, masdi TJ Mechanical engineering and machinery Abstract—Piping systems in refineries and petrochemical plants are exposed to corrosive environment causing various types of degradation mechanisms. One of the damage mechanisms experienced is gradual wall thinning that causes the pipe to leak. Since the piping systems carry hydrocarbons or other process fluids, the presence of small leak may lead to a hazardous situation. Therefore, proper inspection and maintenance of these systems is essential for maintaining a safe and continuous operation. Risk-based inspection (RBI) strategy has been adopted to establish the inspection strategy for piping systems where the strategy is based on risk calculated. Risk is defined as the product of the probability of failure and its consequences of failure. Assessing the failure probability for piping systems in RBI approach typically follows the guideline by American Petroleum Institute (API 581) where the method is deterministic. This study explores the available probabilistic analysis techniques in estimating the piping failure probability, namely, degradation analysis and first-order reliability method (FORM). The objective of this paper is to estimate the pipes failure probability using these two techniques where both models require different input data. Degradation analysis only uses the pipe wall thickness data that are usually being collected during inspection for pipes subject to wall thinning. Conversely, FORM model requires data on material properties and physical geometric of the piping system to estimate the failure probability. The failure probability estimated by these two techniques are then compared and discussed. The results showed that the degradation analysis is more conservative compared to FORM. 2009-12-10 Citation Index Journal PeerReviewed application/pdf en http://scholars.utp.edu.my/id/eprint/1767/1/Comparative_Study_between_Degradation_Analysis_and_First_Order_Reliability_Method_for_Assessing_Piping_Reliability_for_Risk-Based_Inspection.doc.pdf Mokhtar, Ainul Akmar and che ismail, mokhtar and mohamad, masdi (2009) Comparative Study between Degradation Analysis and First Order Reliability Method for Assessing Piping Reliability for Risk-Based Inspection. [Citation Index Journal]
spellingShingle TJ Mechanical engineering and machinery
Mokhtar, Ainul Akmar
che ismail, mokhtar
mohamad, masdi
Comparative Study between Degradation Analysis and First Order Reliability Method for Assessing Piping Reliability for Risk-Based Inspection
title Comparative Study between Degradation Analysis and First Order Reliability Method for Assessing Piping Reliability for Risk-Based Inspection
title_full Comparative Study between Degradation Analysis and First Order Reliability Method for Assessing Piping Reliability for Risk-Based Inspection
title_fullStr Comparative Study between Degradation Analysis and First Order Reliability Method for Assessing Piping Reliability for Risk-Based Inspection
title_full_unstemmed Comparative Study between Degradation Analysis and First Order Reliability Method for Assessing Piping Reliability for Risk-Based Inspection
title_short Comparative Study between Degradation Analysis and First Order Reliability Method for Assessing Piping Reliability for Risk-Based Inspection
title_sort comparative study between degradation analysis and first order reliability method for assessing piping reliability for risk-based inspection
topic TJ Mechanical engineering and machinery
url http://scholars.utp.edu.my/id/eprint/1767/
http://scholars.utp.edu.my/id/eprint/1767/1/Comparative_Study_between_Degradation_Analysis_and_First_Order_Reliability_Method_for_Assessing_Piping_Reliability_for_Risk-Based_Inspection.doc.pdf