Renren Zhang

Bio: Renren Zhang is an academic researcher from Xi'an University of Architecture and Technology. The author has contributed to research in topics: Risk assessment & Operational risk. The author has an hindex of 3, co-authored 6 publications receiving 30 citations.

Dynamic probability assessment of urban natural gas pipeline accidents considering integrated external activities

Abstract: Urban gas pipelines usually have high structural vulnerability due to long service time. The locations across urban areas with high population density make the gas pipelines easily exposed to external activities. Recently, urban pipelines may also have been the target of terrorist attacks. Nevertheless, the intentional damage, i.e. terrorist attack, was seldom considered in previous risk analysis of urban gas pipelines. This work presents a dynamic risk analysis of external activities to urban gas pipelines, which integrates unintentional and intentional damage to pipelines in a unified framework. A Bayesian network mapping from the Bow-tie model is used to represent the evolution process of pipeline accidents initiating from intentional and unintentional hazards. The probabilities of basic events and safety barriers are estimated by adopting the Fuzzy set theory and hierarchical Bayesian analysis (HBA). The developed model enables assessment of the dynamic probabilities of consequences and identifies the most credible contributing factors to the risk, given observed evidence. It also captures both data and model uncertainties. Eventually, an industrial case is presented to illustrate the applicability and effectiveness of the developed methodology. It is observed that the proposed methodology helps to more accurately conduct risk assessment and management of urban natural gas pipelines.

An integrated methodology to manage risk factors of aging urban oil and gas pipelines

Abstract: Aging urban oil and gas pipelines have a high failure probability due to their structural degradation and external interference. The operational safety of the aging urban oil and gas pipeline is challenged by different hazards. This paper proposes a novel methodology by integrating an index-based risk evaluation system and fuzzy TOPSIS model for risk management of aging urban oil and gas pipelines, and it is carried out by evaluating the priority of hazards affecting pipeline safety. Firstly, the hazard factors of aging urban oil and gas pipelines are identified to establish an index-based risk evaluation system. Subsequently, the fuzzy TOPSIS model is employed to evaluate the importance of these hazard factors and to decide which factors should be managed with priority. This work measures the importance of a hazard factor from three aspects, i.e. occurrence (O), severity (S) and detectability (D), and the weights of these three parameters are determined by a combination weight method. Eventually, the proposed methodology is tested by an industrial case to illustrate its effectiveness, and some safety strategies to reduce the operational risk of the pipeline are presented. The proposed methodology is a useful tool to implement more efficient risk management of aging urban oil and gas pipelines.

A semi-quantitative methodology for risk assessment of university chemical laboratory

Abstract: University chemical laboratory is a high-risk place for teaching and scientific research due to the presence of various physical and chemical hazards. In recent years, university chemical laboratory accidents occur frequently. This urges the need to enhance university chemical lab safety. A semi-quantitative methodology comprising Matter-Element Extension Theory (MEET) implemented with Combination Ordered Weighted Averaging (C-OWA) operator is proposed to assess the risk of a university chemical laboratory. First, an index-based risk assessment system of university chemical laboratory is built by identifying various risk factors from a system perspective. Then, C-OWA operator is used to calculate the weight of assessment indices, whereas MEET is employed to determine the correlation degree of assessment indices. Finally, the comprehensive risk of university chemical laboratories is assessed, and some safety measures are proposed to reduce the risk of university chemical laboratories. The applicability of the proposed methodology is tested using a practical case. It is observed that the methodology can be a useful tool for risk assessment and management of university chemical laboratories.

Risk-based pipeline integrity management: A road map for the resilient pipelines

Abstract: Pipelines are the most vital energy-transportation mediums of today’s energy-intensive economies. To a level, pipeline integrity is tied to the continuous development and robustness of modern societies, where major failures may result in dire environmental, societal, and economic consequences. Therefore, pipeline safety and integrity are crucial for a sustainable future and responsible development. Pipeline integrity management has been a topic of interest for regulators, practitioners, and academicians alike. Over the past four decades, integrity management has evolved from prescriptive visual inspection and assessment to risk-based integrity management using real-time data. This paper aims to capture the evolution of risk-based methods in integrity management, focusing on the last two decades. The paper answers four primary questions: 1 What is integrity management, and how has it evolved? 2 How does the concept of risk fit in integrity management? 3 What are the methods used to assess and manage pipeline integrity? 4 How will integrity accommodate Industry 4.0? This article briefly defines the term integrity, how it has progressed and subsequently provides a structured review and analysis of the public domain literature. The paper focuses on risk-based methods adopted to different integrity management elements and applied at different stages of the pipeline’s life cycle. The paper concludes by evaluating the research progress, the gaps in knowledge, and their implication on adopting Industry 4.0.

Modified FMEA hazard identification for cross-country petroleum pipeline using Fuzzy Rule Base and approximate reasoning

Abstract: The pipeline industry's existing and new safety challenges require flexible and powerful techniques for performing a risk-based analysis of cross-country petroleum product pipeline systems. One of the traditional tools for the prediction of pipeline failure is the Failure Mode and Effects Analysis (FMEA) technique due to its ease of application. However, many limitations have been identified in its application especially for cross-country pipelines in developing countries. Firstly, failure data is often either unavailable or unreliable, therefore identification of the risk priority numbers for the three failure factors (i.e. probability of failure, severity and detection) relies on experts' elicitation. Secondly, domain experts often provide diverse opinions and knowledge, which could produce different assessment rankings and it is often difficult to harmonise due to the multidisciplinary nature of the FMEA team. Thirdly, there is a lack of a systematic way of accounting for the relative importance of individual failure factors, which carries the risk of the assessment results not representing the true risk picture of the assessed system. Consequently, this paper proposes a new approach, called the modified FMEA, by integrating the noted benefits of hybrid FMEA with Fuzzy Rule Base (FRB) and FMEA with Grey Relations Theory (GRT) in order to overcome the identified drawbacks. The study utilises both the fuzzy and the grey theory to include experts' diverse opinions and to assign a relative weighting to each assessment factor in the risk assessment. The results of the risk assessment are then used to determine the risk priority and rank the failure modes under different types of conditions. A case study of Nigeria's petroleum product pipeline system 2 B is conducted to examine the applicability and validity of the new approach. The results show the practical application of the methodology in this new domain. The new approach offers a more effective method for identifying product pipeline system hazards and risk analysis in geographies with limited or unreliable data. The application of this new methodology in the oil and gas cross-country pipeline domain will aid decision making under uncertainty for pipeline inspection and maintenance.

Dynamic probability assessment of urban natural gas pipeline accidents considering integrated external activities

Abstract: Urban gas pipelines usually have high structural vulnerability due to long service time. The locations across urban areas with high population density make the gas pipelines easily exposed to external activities. Recently, urban pipelines may also have been the target of terrorist attacks. Nevertheless, the intentional damage, i.e. terrorist attack, was seldom considered in previous risk analysis of urban gas pipelines. This work presents a dynamic risk analysis of external activities to urban gas pipelines, which integrates unintentional and intentional damage to pipelines in a unified framework. A Bayesian network mapping from the Bow-tie model is used to represent the evolution process of pipeline accidents initiating from intentional and unintentional hazards. The probabilities of basic events and safety barriers are estimated by adopting the Fuzzy set theory and hierarchical Bayesian analysis (HBA). The developed model enables assessment of the dynamic probabilities of consequences and identifies the most credible contributing factors to the risk, given observed evidence. It also captures both data and model uncertainties. Eventually, an industrial case is presented to illustrate the applicability and effectiveness of the developed methodology. It is observed that the proposed methodology helps to more accurately conduct risk assessment and management of urban natural gas pipelines.