Probability Calculation of Equipment Impact Based on Reliability Method

2014 ◽  
Author(s):  
Jiang Lu ◽  
Wen Wu ◽  
Zhenyong Zhang ◽  
Jinyuan Zhang
Keyword(s):  
Natural Gas ◽  
Survey Data ◽  
Fault Tree ◽  
Gas Pipelines ◽  
Impact Frequency ◽  
Dense Population ◽  
Natural Gas Pipelines ◽  
Reliability Based Design ◽  
Probability Calculation ◽  
The Impact

In order to apply the Reliability Based Design and Assessment (RBDA) methodology to evaluate the equipment impact on the onshore natural gas transmission pipelines in China, a research project was undertaken by China Petroleum Pipeline Engineering Corporation (CPPE) based on the framework developed by C-FER Technologies (C-FER) in “Guidelines for Reliability Based Design and Assessment of Onshore Natural Gas Pipelines” (sponsored by PRCI). The objective of the project was to collect native data and calibrate the probability models[1] in order to make it suitable for the situations in China where there is dense population and many newly-built high pressure and large diameter pipelines. The equipment impact model consists of two components: a) the impact probability model which calculates the frequency of mechanical interference by excavation equipment; and b) the failure model which calculates the probability of failure in a given impact. A detailed survey was undertaken in 2012 in order to collect the data required to calculate the impact frequency and the load applied by an excavator to a pipeline. The survey data for impact frequency calculation was gathered based on 19,300km of transmission pipelines from 4 operating companies in China. They reflect current prevention practices and their effectiveness. The frequencies of basic events summarized in this survey used to calculate the probabilities of the fault tree are generally agreement with the data summarized in PRCI’s report. The impact frequencies calculated by the fault tree under typical prevention measures are 400%, 200%, 20% and 0% higher than that in PR-244-9910 report for class 1, class 2, class 3 and class 4 areas respectively, which is due to dense population and more construction activities. Bucket digging forces of 321 types of excavators from 20 manufacturers were gathered. The survey data of the forces are slightly higher than that in the PR-244-9729 report as a whole due to the increase in mechanical efficiency of excavators in recent years. The excavator maximum quasi-static load model was calibrated correspondingly. Equipment impact probability calculation and model sensitivity analysis results are described to present several characteristics of onshore transmission natural gas pipelines in China.

scholarly journals Investigating the likelihood of catastrophic events in natural gas pipelines using an integration of fault tree analysis and What-if methods

Sigurnost ◽  
2016 ◽  
Vol 58 (1) ◽  
pp. 19-30
Author(s):  
Mehrzad Ebrahemzadih ◽  
Payam Amer Haedari
Keyword(s):  
Natural Gas ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Gas Pipelines ◽  
Catastrophic Events ◽  
Tree Analysis ◽  
Natural Gas Pipelines

SAŽETAK: Prirodni plin danas se smatra najvećim izvorom energije potrebne stambenim područjima i industriji. Pogled na tehnologije kojima se Iran koristi otkriva da su plinovodi najbolji i najsigurniji način za distribuciju prirodnog plina u zemlji. Ovaj izvor energije, koji se ponekad naziva čistim gorivom, ima stratešku ulogu u opskrbi potrebne energije. S druge strane, opskrba gorivom mora biti stalna, ali i sigurna. Stoga se zaključuje da su potrebne odgovarajuće mjere za upravljanje rizicima od curenja, požara i eksplozija na ovakvim postrojenjima. Za postizanje toga cilja najpotrebnije je ustanoviti uzroke nesreća i ispitati pouzdanost. Nadalje, neizbježno se mora procijeniti vjerojatnost događanja nesreće na cjevovodima. Jedan od ključnih koraka u procesu vrednovanja rizika jest procjena vjerojatnosti mogućih nesreća. Članak se koristi FTA (fault tree analysis) metodologijom za proučavanje načina procjene vjerojatnosti nesreća na cjevovodima za prirodni plin. Nadalje, ponuđena je i nova metoda temeljena na pridruživanju težina stablu kvarova, a ‘what-if’ (što-ako) scenarij služi za utvrđivanje opasnosti pri transportu prirodnog plina od njegova glavnog izvora. Na osnovi rezultata studije predlaže se da se vjerojatnost događanja nesreća na cjevovodima za prirodni plin kontrolira tehničkim i sustavnim pristupom kojim se utvrđuju i kontroliraju uzroci tih nesreća.

scholarly journals Modified Leakage Rate Calculation Models of Natural Gas Pipelines

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Qingmin Hou ◽  
Daheng Yang ◽  
Xiaoyan Li ◽  
Guanghua Xiao ◽  
Siu Chun Michael Ho
Keyword(s):  
Natural Gas ◽  
Flow Rate ◽  
Leakage Rate ◽  
Rate Change ◽  
Feedback Effect ◽  
Gas Pipelines ◽  
Natural Gas Pipelines ◽  
Pipe Model ◽  
Flow Rate Change ◽  
The Impact

The leakage rate is an essential parameter for the risk assessment and failure analysis of natural gas pipelines. The leakage rate of a natural gas pipeline should be calculated quickly and accurately to minimize consequences. First, in this study, models to estimate the leakage rate of natural gas pipelines are reclassified, and the theoretical range of application for each model is also analysed. Second, the impact of the leakage on the flow rate upstream of the leak point is considered, and the method of successive approximation is used to realize this feedback effect of flow rate change. Then, a modified hole-pipe model is developed to calculate the natural gas leakage rate in this paper. Compared with the leakage rate calculated by the hole-pipe model, the leakage rate calculated by the modified hole-pipe model is smaller and closer to the actual leakage rate due to the consideration of the feedback effect of the flow rate change. Finally, the leakage rate curves of the hole-pipe model and the modified hole-pipe model under different d/D conditions are obtained through simulation. The simulation results show that the modified hole-pipe model is able to calculate the leakage rate of any leak aperture, such as the hole-pipe model, and also at a higher accuracy level than the hole-pipe model.

Multi-Factor and Polymorphism Failure Probability Calculation for Natural Gas Pipelines

2013 ◽  
Vol 401-403 ◽  
pp. 2170-2174 ◽  
Author(s):  
Ya Ping Yang ◽  
Yong Mei Hao ◽  
Zhi Xiang Xing
Keyword(s):  
Natural Gas ◽  
Bayesian Network ◽  
Calculation Model ◽  
Gas Pipelines ◽  
Single Factor ◽  
Natural Gas Pipelines ◽  
Natural Gas Pipeline ◽  
Quantitative Calculation ◽  
Failure State ◽  
Probability Calculation

A Bayesian network quantitative calculation model for urban natural gas pipelines was established by using the unique logic of a Bayesian network in handling complicated risk systems. By using a natural gas pipeline as an example, failure situations such as single factor polymorphism, double factor polymorphism, and multi-factor polymorphism of a pipeline were quantitatively calculated to obtain the probability of top events and the structural importance of basic factors. The proposed method not only reflects clearly the effects of different factors but also predicts the failure state of urban natural gas pipelines comprehensively and accurately. The results of the proposed method can serve as a significant reference for the risk management and fault processing of city natural gas pipelines.

Reliability Based Design and Assessment for Location-Specific Failure Threats With Application to Natural Gas Pipelines

2006 ◽  
Author(s):  
Maher Nessim ◽  
Wenxing Zhou ◽  
Joe Zhou ◽  
Brian Rothwell
Keyword(s):  
Natural Gas ◽  
Individual Risk ◽  
Gas Pipelines ◽  
Limit States ◽  
Integrity Assessment ◽  
Natural Gas Pipelines ◽  
Risk Criteria ◽  
Reliability Based Design ◽  
Unstable Slope ◽  
The Individual

The acceptance criteria used in Reliability Based Design and Assessment (RBDA) are defined as a set of reliability targets (where reliability is defined as 1.0 minus the probability of failure). Because of the linear nature of pipeline systems, reliability targets are defined on a per km-year basis. Such targets are directly applicable to failure causes (or limit states) that are equally likely to occur anywhere along a segment of the pipeline (e.g. equipment impact or yielding/rupture of defect-free pipe under internal pressure). They are, however, not directly applicable for design and assessment situations involving limit states that apply at known specific locations. Examples include design for geotechnical loads on a particular unstable slope or integrity assessment of specific corrosion defects based on in-line inspection data. In previous work, reliability targets for natural gas pipelines have been developed on the basis of appropriate societal and individual risk criteria. This paper describes an approach to adapt these targets, and demonstrate compliance with them, for location-specific limit states. The approach is based on using separate checks to ensure that the individual and societal risk criteria underlying the targets are met. An example is included to demonstrate application of the approach to design a pipeline on an unstable slope.

Reliability Based Design and Assessment for Location-Specific Failure Threats With Application to Natural Gas Pipelines

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
Maher Nessim ◽  
Wenxing Zhou ◽  
Joe Zhou ◽  
Brian Rothwell
Keyword(s):  
Natural Gas ◽  
Individual Risk ◽  
Gas Pipelines ◽  
Limit States ◽  
Integrity Assessment ◽  
Natural Gas Pipelines ◽  
Risk Criteria ◽  
Reliability Based Design ◽  
Unstable Slope ◽  
The Individual

The acceptance criteria used in reliability based design and assessment are defined as a set of reliability targets (where reliability is defined as 1.0 minus the probability of failure). Because of the linear nature of pipeline systems, reliability targets are defined on a per kilometer-year basis. Such targets are directly applicable to failure causes (or limit states) that are equally likely to occur anywhere along a segment of the pipeline (e.g., equipment impact or yielding/rupture of defect-free pipe under internal pressure). They are, however, not directly applicable for design and assessment situations involving limit states that apply at known specific locations. Examples include design for geotechnical loads on a particular unstable slope or integrity assessment of a corrosion defect at a specific location (as determined by in-line inspection). In previous work, reliability targets for natural gas pipelines have been developed on the basis of appropriate societal and individual risk criteria. This paper describes an approach to adapt these targets and demonstrate compliance with them, for location-specific limit states. The approach is based on using separate checks to ensure that the individual and societal risk criteria underlying the targets are met. An example is included to demonstrate application of the approach to design a pipeline on an unstable slope.

Condition-Based Optimal Maintenance Decision Modeling for Corroding Natural Gas Pipelines

2014 ◽  
Author(s):  
S. Zhang ◽  
W. Zhou ◽  
S. Kariyawasam ◽  
T. Huang
Keyword(s):  
Natural Gas ◽  
Probability Of Detection ◽  
Metal Loss ◽  
Gas Pipelines ◽  
Natural Gas Pipelines ◽  
Inspection Interval ◽  
Optimal Maintenance ◽  
Maintenance Decision ◽  
The Cost ◽  
The Impact

This paper investigates the optimal timing of the first inspection for newly-built onshore underground natural gas pipelines with respect to external metal-loss corrosion by considering the generation of corrosion defects over time and time-dependent growth of individual defects. The non-homogeneous Poisson process is used to model the generation of new defects and the homogeneous gamma process is used to model the growth of individual defects. A realistic maintenance strategy that is consistent with the industry practice and accounts for the probability of detection (PoD) and sizing errors of the inspection tool is incorporated in the investigation. Both the direct and indirect costs of failure are considered. A simulation-based approach is developed to numerically evaluate the expected cost rate at a given inspection interval. The optimal inspection interval is determined based on either the cost criterion or the safety criterion. An example gas pipeline is used to examine the impact of the cost of failure, PoD, and the excavation and repair criteria on the optimal inspection interval through parametric analyses. The results of investigation will assist engineers in making the optimal maintenance decision for corroding natural gas pipelines and facilitate the reliability-based corrosion management.

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