Article

Risk-Based Maintenance (RBM): A new approach for process plant inspection and maintenance

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Abstract

This paper discusses recently proposed methodology for the design of an optimum maintenance management program. The methodology is based on integrating a reliability approach and a risk assessment strategy to obtain an optimum maintenance schedule. The method is called risk-based maintenance (RBM). First, the likely equipment failure scenarios are formulated. Out of the many likely failure scenarios, the ones that are most credible are subjected to a detailed study. Detailed consequence analysis is done for the selected scenarios. Subsequently, a fault tree analysis is performed to determine the probability of failure. Finally, risk is computed by combining the consequence analysis and the probability analysis results. The calculated risk is compared against known acceptable criteria. The frequency of maintenance tasks is obtained by minimizing the estimated risk. The proposed methodology is used to answer two questions: Which equipment should be included in a scheduled maintenance program? When should the maintenance be scheduled? Offshore oil and gas process facilities involve hazardous chemicals (highly flammable and toxic) at extreme conditions of temperature and pressure. Proper maintenance of process equipment is one of the important activities to ensure safe and continuous operation of the facility. RBM methodology has been used to develop a detailed maintenance plan for safe and fault free operation of the facility. © 2004 American Institute of Chemical Engineers Process Saf Prog, 2004

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... The most effective tool for estimating the likelihood of hazard and associated consequences is probabilistic risk assessment [5]. Several researchers have demonstrated the application of a RBM strategy [2,3,[6][7][8][9][10][11][12].In the beginning of the twentieth century, the American Society of Mechanical Engineers focused on performance criteria to improve safety and reduce the frequency of failure [10]. Later, the importance of risk was recognized as a significant measure of systems safety. ...
... The most effective tool for estimating the likelihood of hazard and associated consequences is probabilistic risk assessment [5]. Several researchers have demonstrated the application of a RBM strategy [2,3,[6][7][8][9][10][11][12].In the beginning of the twentieth century, the American Society of Mechanical Engineers focused on performance criteria to improve safety and reduce the frequency of failure [10]. Later, the importance of risk was recognized as a significant measure of systems safety. ...
... In their study a reverse fault tree was used to determine the optimal maintenance intervals [2]. Recently, researchers [3,10] reported the significance of applying a RBM strategy in process industries. ...
Article
Processing facilities in a marine environment may not remain safe and available if they are not well maintained. Dynamic risk-based maintenance (RBM) methodology is a tool for maintenance planning and decision making, used to enhance the safety and availability of the equipment. It also assists in identifying and prioritizing the maintenance of equipment based on the level of risk. This article discusses an advanced methodology for the design of an optimum maintenance program integrating a dynamic risk-based approach with a maintenance optimization technique. In this study, Bayesian Network (BN) is employed to develop a new dynamic RBM methodology that is capable of using accident precursor information in order to revise the risk profile. The use of this methodology is based on its failure prediction capability which optimizes the cost of maintenance. The developed methodology is applied to a case study involving a failure of a separator system in the offshore oil and gas production platform considering marine environments. The result shows it is essential that the valve system in the separator needs to be planned for maintenance once every 25 days; however, the cooler system can be planned for repairs once only biennially. A sensitivity analysis is also conducted to study the criticality of the operating system.
... In traditional forms of FTA which utilize ordinary likelihood for BEs (Khan and Haddara, 2004) (Dan et al., 2014) (Abimbola et al., 2016) (Sklet et al., 2006) (Rathnayaka et al., 2012) the precise value of frequency or probability is determined by expert opinion or historical information. To enhance the accuracy of failure rates in FTA, it is best to derive them from historical data such as recorded failure rates of tools or units whenever the data is accessible and reliable. ...
... The consequences are transformed to economic loss. Some scientific endeavors have addressed the issue of expressing severity of failure in a form of economic loss (Khan and Haddara, 2004) (Arunraj & and Maiti, 2009). This way we are able to express all losses in a common unit. ...
... In this paper human injuries is neglected and only loss of life is calculated. The compensation cost for loss of life is assumed one million dollars per loss of life (Khan and Haddara, 2004). Indirect costs such as environmental cost, loss of reputation and opportunity loss are neglected due to complex and uncertain calculations. ...
Article
Fire is the most prevalent accident in natural gas facilities. In order to assess the risk of fire in a gas processing plant, a fault tree analysis (FTA) and event tree analysis (ETA) has been developed in this paper. By utilizing FTA and ETA, the paths leading to an outcome event would be visually demonstrated. The framework was applied to a case study of processing plant in South Pars gas complex. All major underlying causes of fire accident in a gas processing facility determined through a process hazard analysis (PHA). Fuzzy logic has been employed to derive likelihood of basic events in FTA from uncertain opinion of experts. The outcome events in event tree has been simulated by computer model to evaluate their severity. In the proposed methodology the calculated risk has the unit of cost per year which allows the decision makers to discern the benefit of their investment in safety measures and risk mitigation.
... Failure of equipment incurred downtime and unavailability of the plant, which may prolong with the inadequacy of spare parts. In view of this situation, the Risk Based Maintenance (RBM) is used by the plant maintenance to reduce the risk from the unexpected failure happen in the operation premises [14]. [15] prioritized and quantified the risk from the risk based maintenance activity. ...
... Hence, [16] suggested on the implementation of regular inspection activity for the high risk spare part in order to avoid the potential failure and achieving appropriate risk toleration. [14] used the risk matrix to define the risk and consequences. . Besides that, [17] developed checklist for chemical industry and [18] used the check list for listing the possible risk that is related to plant hazard in operation. ...
... 5,No. operation premises [14]. [15] prioritized and quantified the risk from the risk based maintenance activity. ...
Article
Full-text available
Financial losses due to spare part breakdown in plant operation have created an upsetting situation among stakeholders. The failure increase the cost of repair and production downtime.. Obviously, maintenance planner tends to increase the spare part inventory level in order to meet the operational requirement and this in return has increased the inventory cost. The maintenance and inventory function is important in order to ensure the plant operate accordingly. Moreover, it is necessary for the plant maintenance to balance the issue of shortage and excess of inventory in plant maintenance. In view of this situation, the spare parts become a critical matters and it is good starting point to tackle the issues from looking at the perspective of spare parts inventory risk. This paper explain about the development of risk based technique using the shortage and excess situation of spare parts inventory by using the Breakdown Probability Table to quantify the risk for decision making purpose.
... Consequence estimation is used to determine the potential for damage or injury from specific unwanted events. Quantification of consequences has been usually carried out in terms of production loss, human health loss, assets loss, and environmental loss (Khan and Haddara, 2004). The assessment of consequences can be performed using a huge number of mathematical and empirical models; a description of many available approaches has been presented by Arunraj and Maiti (2009). ...
... Risk-based maintenance is designed to study all the failure modes, determining the risk associated with those failure modes, and developing a maintenance strategy that minimizes the occurrence of the high-risk failure modes (Arunraj and Maiti, 2007;Okoh and Hauge, 2013). Risk-based maintenance and inspection strategies have been developed to provide a basis for not only taking the reliability of a system into consideration when making decisions regarding the type and the time for maintenance actions, but also to be able to take into consideration the risk that would result as a consequence of an unexpected failure (Khan and Haddara, 2004). ...
Article
The objective of this review is to analyse the progress of Risk Assessment during the last decades and to offer an overview on its recent advancements and possible future direction for chemical and process industries. Despite the general approach of Quantitative Risk Assessment (QRA) is unchanged since its origin in the early 1980s, QRA has continuously evolved in different forms and its fields of application have enlarged significantly beyond process safety, where it has always been traditionally developed and used for chemical process industries. Now risk assessment techniques play a fundamental role in process design, implementation of safety systems, inspection and maintenance planning as well as operation management. Eventually risk assessment has become an essential tool for the development, continued operation and expansion of process installations. On the other hand, QRA limitations, such as its inability to update the risk picture, led to the development of several recent dynamic risk assessment approaches, whose methodological and applicative contributions are presented in this paper. This demonstrates that risk assessment is in continuous development; nevertheless, it still shows many challenges to face: the way forward is improving its preciseness and its capability to be dynamically updated, that it will be useful to support real-time decision-making.
... In addition, consequence analysis widely consists of different mathematical models. Khan and Haddara (2004) broadly explained the quantifying of the consequences category based on mathematical techniques. ...
... The TE of the FT was selected as release of crude oil from separation. The developed FT is illustrated in Fig. 4. In order to obtain probability of each BE, one method is to obtain the probabilities from a reliability handbook or by referring to previous literature such as Bhandari et al. (2016); and Khan and Haddara (2004). However, the failure probability of a specific BE can differ according to various environmental and operational conditions. ...
... Competitive priorities such as cost, quality, delivery performance, flexibility and reliability are the basis for the development of distinctive capabilities in the production system (CHOUDHARI et al., 2013;KHAN, HADDARA, 2004). They are the pillars of the operating system and represent an important internal factor of operations (PENG et al., 2011;DÍAZ, MARTÍN, 2007). ...
... This security stock is not financed by the customer, but it is also a determining factor when signing the supply contract for a certain period. The value of this stock is intended to provide security to the supply contract and may be reduced or increased as the reliability of the equipment and process fluctuates (KHAN, HADDARA, 2004). ...
Chapter
Industrial failures are associated with poor maintenance planning, directly affecting organizational productivity. When equipment failures occur, established contracts allow fines to be imposed on organizations, sometimes due to delivery delays or product failures due to poor quality. The aim of this paper was to perform a literature review on the elements that cause risks of contractual fines due to equipment unavailability. To perform this work, a literature review was made based on published scientific articles on topics of predictive maintenance, preventive maintenance and corrective maintenance, production planning and control (PPC), financial risks for contractual fines and availability of machinery in industrial processes, as well as maintenance workforce qualification. Maintenance and operation, as the most important administrative and operational functions of production, are responsible for meeting the following requirements: quality, speed, reliability, flexibility and cost. As a result, it was found in the literature that a well-trained and motivated maintenance team performs higher quality short-term tasks, reducing machine repair times, and reducing the number of fines for failure to meet contractual deadlines. These results were corroborated by verification in four supply chain companies in the agricultural and construction machinery sector.
... Application of BN in accident modelling has been previously explained by different researchers (Simoncic, 2004;Khakzad et al., 2013). Some of priorities of using BN in comparison with the conventional methods such as FT and ET analysis are the ability to model complex systems, reducing parameter uncertainty by having new evidences, and being user-friendly by applying a compact graphical approach (Khan and Haddara, 2004a;Weber et al., 2012). A brief description of the fundamentals of BN for mapping the possible events that may cause an accident and the potential consequences is presented in section 2.1. ...
... Whenever the estimated risk exceeds the acceptable criteria, further analysis is warranted to reduce the risk using risk management plan. It should be noted that the acceptable risk value can be altered for different organizations and systems (Khan and Haddara, 2004a). In fifth step, the backward inference on the BN is employed (Fung and Favero, 1994). ...
Article
The main objective of the maintenance process is to increase equipment's life while maintaining the safety and reliability of the process systems. The maintenance planning concerns identification of what and how to inspect, how often to inspect, and what maintenance actions to be taken. Even though the maintenance may be used as an effective means for controlling the degradation of systems, the procedures may also have considerable impact on the operation. It results in direct and indirect economic consequences in terms of shutdowns and unavailability of systems. Therefore, it is necessary to plan maintenance such that a balance is achieved between the expected benefit and the corresponding economic consequences implied by these activities. The objective of this research is to integrate predictive and preventive maintenance strategies in an optimal way to maintain the desired availability and safety integrity level while minimizing the maintenance intervals. The outcome of this work would help to conserve resources while maintaining overall system availability and the safety. The results showed that the risk-based methodology developed using Bayesian Network increases the reliability of the equipment and also optimizes the cost of maintenance. Application of the developed methodology is demonstrated on the maintenance of a power plant as a case study.
... This may constrain yielding proper results and decisions based on misleading results may generate non-essential maintenance efforts spent in less important areas. To avoid this, risk analysis for asset criticality should be evaluated in well planned manner ensuring that significant sources of risk are reduced or eliminated [5]. ...
... In the matrix in Figure 3 we can compare results obtained in two previous criticality matrices: potential and current. ffz 6,7 i' i 5,4 h' d' h d 3,3 c' e, e' c, g' g 8. Automatize the criticality report, listing the assets ranking per criticality levels, and within each level, classify the assets by common frequencies and severities. Rational for this is related to the type of strategy that will be required to manage them. ...
Chapter
The purpose of this paper is to establish a basis for a criticality analysis, considered here as a prerequisite, a first required step to review the current maintenance programs, of complex in-service engineering assets. Review is understood as a reality check, a testing of whether the current maintenance activities are well aligned to actual business objectives and needs. This paper describes an efficient and rational working process and a model resulting in a hierarchy of assets, based on risk analysis and cost–benefit principles, which will be ranked according to their importance for the business to meet specific goals. Starting from a multi-criteria analysis, the proposed model converts relevant criteria impacting equipment criticality into a single score presenting the criticality level. Although detailed implementation of techniques like root cause failure analysis (RCFA) and reliability centered maintenance (RCM) will be recommended for further optimization of the maintenance activities, the reasons why criticality analysis deserves the attention of the engineers, maintenance and reliability managers are here precisely explained. A case study is presented to help the reader to understand the process and to operationalize the model.
... There is a great deal of research on RBM and optimization of maintenance plans (Abbassi et al., 2016;Barua et al., 2016;Dawotola et al., 2012;Khan & Haddara, 2004;Krishnasamy et al., 2005). Dawotola et al. (2012) proposed a maintenance plan considering both economic issues and risk aspects for an oil pipeline system. ...
... After that, it derives several combinations of maintenance strategies for apparatuses with a greater improvement effect and also in terms of maintenance methods, in consideration of customers' budgets. Also, the AHMS suggests an appropriate strategy in aspects of each reliability index and budgets among the maintenance strategies derived in Figure 9(c) an implements maintenance according to customers' choices [12][13][14]. ...
Conference Paper
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The accelerating pace of industrialization has led to an increase in demand for electrical power. A reliable and stable power supply is required for transmission and distribution apparatuses. In addition, as economic loss increases due to the failure and deterioration of power systems, an asset health solution for power system is required to provide a systematic management service for its lifecycle by combining a product, service and operating system with the prediction of failure occurrence by analyzing real-time operating data and condition data, optimal maintenance strategy based on exact condition assessment and decision making for investment of new apparatuses. In this paper, in light of the above, we developed an Asset Health Management Solution (AHMS). It has been applied to high-voltage substations of major oil refinery companies in Korea. The AHMS is able to monitor, collect and save the real-time condition, operation and inspection data in cooperation with the operator and manufacturer of apparatuses. It consists of a server for the collection of substation information, a data center, and a web-based operating software. The server for the collection of substation information collects and saves on-line data such as operating data for diagnosis and off-line data, such as drawing, specification, on-site inspection data and maintenance trends, as well as data transmission through security protocol. The data center is composed of several servers for data collection, user access, application, algorithm analysis, database, alarm, and control as an integrated system, which collect all the server data of each substation information. In addition, it transmits the analytical result of algorithm such as lifetime and reliability model, health assessment, system reliability and maintenance strategy to web-based asset management software for the facility operator and manufacturer. The asset management software of AHMS implements asset management, operating work management, as well as the function of condition monitoring and algorithm result monitoring. Asset management software is composed of three stages: power apparatus information management and monitoring, risk assessment, and various visualization for diagnostic result. In the first stage, the operator registers the power apparatus's information, manages its maintenance history, and monitors its status information. In the second stage, the condition of the power apparatus is evaluated by risk analysis using its status data and history data. Then, maintenance scheduling and estimated costs are prioritized depending on the result of risk analysis. Work manual is created and it is sent to on-site engineers. In the last stage, the operator can check on the report of analysis through various visualization screens.
... The types of loss such as human, production, asset, environmental and reputation loss are taken into consideration to exhibit overall monetary loss due to a failure event. In the previous research related to consequence assessment of pipeline failure, reputation loss is commonly neglected due to the difficulties to quantifying the factors into monetary value [4,5]. Moreover, reputation is timedependent and it is event's impact-dependent [6,7]. ...
... Son application s'est étendue à l'industrie des procédés chimiques au cours des années 1970 et 1980, en particulier dans l'étude Canvey (HSE, 1978) et l'étude Rijnmond (Rijnmond Public Authority, 1982) qui sont des exemples bien connus.Au début des années 2000, la QRA était principalement utilisée comme activité de vérification(Falck et al., 2000), alors qu'elle joue désormais un rôle pertinent dans différents aspects du cycle de vie des procédés de traitement.Hendershot et al. (2006) ont démontré l'intérêt de l'application de la QRA dès les premières étapes du processus de conception (phases de faisabilité et de conception) afin de comprendre les caractéristiques de sécurité inhérentes aux options de conception. Comme lesoulignent Shariff & Zaini (2013), la QRA a été souvent appliquée à la conception détaillée et à l'ingénierie car, à ce stade préliminaire, les concepteurs de procédés manquent généralement d'informations sur le niveau de risque de l'installation.Une autre application pertinente de la QRA repose son intégration aux activités d'exploitation et de maintenance est actuellement largement reconnue, après que de nombreux chercheurs et industriels ont abordé cet aspect(Apeland & Aven, 2000 ;Arunraj & Maiti, 2009 ;Khan & Haddara, 2004). La maintenance basée sur le risque est conçue pour étudier les modes de défaillance et leurs effets, déterminer leurs risques et développer une stratégie de maintenance minimisant l'occurrence des modes de défaillance les plus critiques. ...
Thesis
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Abstract --- With the rapid technological growth of existing and emerging industrial facilities, it has become necessary to improve the safety of these facilities. Several risk analysis methods (qualitative and semi-quantitative) have been developed in recent decades, such as LOPA (Layers Of Protection Analysis), risk matrix, risk graph, etc. However, these methods often prove to be insufficient or questionable for decision-making regarding unacceptable accident scenarios. In such situations, risk analysts often refer to Quantitative Risk Analysis (QRA), which is based on understanding and quantifying the characteristics of accidental phenomena. QRA goes back several decades and was initially used in the nuclear industry, and then spread to other sectors, mainly to the process industry. However, it turns out that its application to the latter is not all the time obvious, due to the diversity of processes, hazardous materials and equipment used. Indeed, this complexity requires continuous improvement of QRA techniques. The present research work has a dual purpose: on the one hand, it answers methodological questions by integrating models from analytical and numerical physics into the QRA and, on the other hand, it focuses on the analytical and numerical aspects of this integration in order to overcome some limitations of empirical and semi-empirical approaches. The proposed Sedov-Taylor model makes it possible to estimate the blast wave effects generated by a strong explosion, such as BLEVE (Boiling Liquid Expanding Vapor Explosion), by describing its characteristic quantities (radius, velocity and overpressure). With the emergence of Computational Fluid Dynamics (CFD), which consists in studying the fluid dynamics by the numerical resolution of the governing equations, it turns out that it would be very interesting to propose a numerical approach to study the BLEVE consequences, in particular the thermal effects, by using a CFD code taking into account the analytical aspects and equations of this type of effect.
... Many researchers have worked on risk-based approaches to maintenance optimization ( Vatn et al., 1996 ;Clarotti et al. 1997 ;Khan and Haddara 2004 ). Xu et al. (2012) introduced a risk-based optimization model for the system maintenance-scheduling problem, which included optimizing cost and availability of the system by balancing of failure risk and system maintenance. ...
Article
Scheduling of the maintenance activities is considered, in which the duration of activities is uncertain, delivery date of the maintenance shutdown is predefined, and activities are multi-mode. The problem is a multi-mode time-constrained project scheduling problem (MTCPSP). The glycol regeneration unit in a gas refinery is as the case study. Based on the effect of equipment or sub-equipment on the system reliability, the importance value of equipment and sub-equipment within the system is determined, and these values are used in a heuristic algorithm as a priority rule for choosing activities in the schedule. Outcomes demonstrate the performance of the algorithm in early or on time delivery of the planned shutdown and reveal that if during the execution of the maintenance shutdown, it is forced to shorten the shutdown period, at each time before the deadline, the plant can be started up with the maximum possible improvement of the system reliability.
... One of the application areas of risk assessment regarding asset-management system improvement is the concept of risk-based inspection and maintenance (RBIM). RBIM can be used to identify critical equipment where inspections will provide the most benefit in reducing the overall risk [1]. This approach was primarily developed for the needs of the oil and gas sector, both for offshore and onshore facilities [2]. ...
Article
Full-text available
Enterprises today are increasingly seeking maintenance management strategies to ensure that their machines run faultlessly. This problem is particularly relevant in the mining sector, due to the demanding working conditions of underground mines and machines and equipment-operating regimes. Therefore, in this article, the authors proposed a new approach to mining machinery maintenance management, based on the concept of risk-based maintenance (RBM) and taking into account safety issues. The proposed method includes five levels of analysis, of which the first level focuses on hazard analysis, while the next three are connected with a risk evaluation. The final level relates to determining the RBM recommendations. The recommendations are defined in relation to the three main improvement areas: maintenance, safety, and resource availability/allocation. The proposed approach is based on the use of fuzzy logic. To present the possibilities of implementing our method, a case study covering the operation of selected mining machinery in a selected Polish underground mine is presented. In the case of mining machinery, fourteen adverse-event scenarios were identified and investigated; general recommendations were also given. The authors have also indicated further directions of research work to optimize system maintenance strategies, based on the concept of risk-based maintenance. Additionally, the discussion about the implementation possibilities of the approach developed herein is provided.
... (a) We analyze the process of the chemical plant explosion and propose 12 key nodes, which correspond to "Accident background," "Cause of accident," "Critical event," and "Accident results." It should be noted that in Hazard and Operability Analysis (HAZOP)and Safety Integrity Level Analysis (SIL), accident consequences are often quantified from production losses, property losses, human damage, and environmental impacts [42,43]. Chemical plant accidents have a significant impact on the environment, because of the characteristics of toxic or non-toxic chemicals, the state of gaseous or liquid chemicals, proximity to rivers or residential areas, and cause a domino effect. ...
Article
Full-text available
Many chemical plant explosion accidents occur along with the development of the chemical industry. Meanwhile, the interaction and influence of various factors significantly increase the uncertainty of the evolution process of such accidents. This paper presents a framework to dynamically evaluate chemical plant explosion accidents. We propose twelve nodes to represent accident evolution and establish a Bayesian network model for chemical plant explosion accidents, combining historical data with expert experience to support the prevention, management, and real-time warning. Hypothetical scenarios and catastrophic explosion scenarios were analyzed by setting different combinations of states for nodes. Moreover, the impacts of factors such as factory type, material form, accident equipment, the emergency response on casualty and property loss are evaluated. We find that sensitivity of property loss and casualties to factory type and ongoing work are less significant; the equipment factors result in more casualties than that from personnel factors; the impact of emergency response on the accident results is significant; equipment safety management and personnel safety training are the most important measures to prevent chemical plant explosion risks.
... In inspection planning, for example, Ratnayake [6] conducted a study dealing with the inspection plan for facility maintenance in an aging oil and gas production plant concerning the inspection plan of equipment maintenance. Khan et al. [7] studied obtaining an optimal test plan for a plant called a risk-based maintenance plan. However, there are few studies on inspection planning for the manufacturing process. ...
Article
Full-text available
Quality improvement activities have been promoted not only in the inspection sector but also in other sectors such as the production sector with the aim of zero defects under the concept of TQC/TQM. Besides improving quality, quality improvement activities contribute to the improvement of the capabilities of manufacturers to deliver at a lower cost. However, because of the increasing severity of global competition, manufacturers face increased pressure to reduce costs, shorten due dates, and increase quality requirements. Thus, these days, the production sector tends to design the production plan with less slack time to reduce production cost and in-process times. As a result, the flexibility of making the inspection plan by the inspection sector is reduced, which may increase the chance for internal and external failures. In this paper, we propose a method of collaborative inspection planning that integrates the inspection plan with the production plan in the production sector. In the method, slack times are intentionally inserted in the production plan, and inspection levels are selected for the inspection plan by the collaborative efforts in consideration of production cost, due dates, and internal and external failure costs. The method generates the strategy map that shows the expected profit based on the possible combinations of the slack times and the inspection levels. The combinations that maximize the expected profit are selected by using the strategy map, and the inspection plan is made based on the inspection levels. The effectiveness of the proposed method is demonstrated through numerical experiments using a simple manufacturing model.
... The BN nodes are shown in Table 1 and described in Appendix A. These nodes describe the attack in terms of attack subject, attack object, attack consequence, and objective conditions. However, it should be noted that in Hazard and Operability Analysis (HAZOP) and Safety Integrity Level Analysis (SIL), incident consequences are often quantified from property loss, human damage, and environmental impacts [48,49]. In a chemical weapon attack, the characteristics of chemical weapons, the dose of weapons, the method of delivery, and the mode of diffusion of chemical substances in the atmosphere have a significant impact on the environment. ...
Article
Full-text available
The chemical terrorist attack is an unconventional form of terrorism with vast scope of influence, strong concealment, high technical means and severe consequences. Chemical terrorism risk refers to the uncertainty of the effects of terrorist organisations using toxic industrial chemicals/drugs and classic chemical weapons to attack the population. There are multiple risk factors infecting chemical terrorism risk, such as the threat degree of terrorist organisations, attraction of targets, city emergency response capabilities, and police defense capabilities. We have constructed a Bayesian network of chemical terrorist attacks to conduct risk analysis. The scenario analysis and sensitivity analysis are applied to validate the model and analyse the impact of the vital factor on the risk of chemical terrorist attacks. The results show that the model can be used for simulation and risk analysis of chemical terrorist attacks. In terms of controlling the risk of chemical terrorist attack, patrol and surveillance are less critical than security checks and police investigations. Security check is the most effective approach to decrease the probability of successful attacks. Different terrorist organisations have different degrees of threat, but the impacts of which are limited to the success of the attack. Weapon types and doses are sensitive to casualties, but it is the level of emergency response capabilities that dominates the changes in casualties. Due to the limited number of defensive resources, to get the best consequence, the priority of the deployment of defensive sources should be firstly given to governmental buildings, followed by commercial areas. These findings may provide the theoretical basis and method support for the combat of the public security department and the safety prevention decision of the risk management department.
... The last two categories have attracted significant attention from researchers for increasing both effectiveness and efficiency of integrity management [18]. Abbassi et al. [19] developed a risk-based model to integrate predictive and preventive maintenance strategies in an optimal way. ...
Article
In this paper, a risk-based optimization methodology for a maintenance schedule considering Process Variables (PVs), is developed within the framework of asset integrity assessment. To this end, an integration of Dynamic Bayesian Network, Damage Modelling and sensitivity analysis are implemented to clarify the behaviour of failure probability, considering the exogenous undisciplinable perturbations. Discrete time case is considered through measuring or observing the PVs. Decision configurations and utility nodes are defined inside the network to represent maintenance activities and their associated costs. The regression analysis is considered to model the impact of perturbations on PVs for future applications. The developed methodology is applied to a case study of Chemical Plant (Natural Gas Regulating and Metering Stations). To demonstrate the applicability of the methodology, three cases of seasonal observations of specific PV (pressure) are considered. The proposed methodology could either analyse the failure based on precursor data of PVs or obtain the optimum maintenance schedule based on actual condition of the systems.
... Consequence estimation is used to determine the potential for damage or injury from specific unwanted events. Quantification of consequences has been usually carried out in terms of production loss, human health loss, assets loss, and environmental loss (Khan and Haddara, 2004). The assessment of consequences can be performed using physical and empirical models (Arunraj and Maiti, 2009). ...
Chapter
This work focuses on the emerging topic of Dynamic Risk Analysis (DRA), as opposed to traditional static risk analysis. DRA fundamentals are introduced by discussing the overall understanding of the risk concepts. Its functioning is described by presenting the dynamic version of the main risk analysis steps, according to the main variables involved: the accident scenario, its frequency and its consequences. The methodological focus is an important aspect to consider in order to avoid any ambiguity between DRA, real-time techniques and traditional risk analysis. Moreover, to better understand DRA, we must understand the framework in which it is encompassed. All these elements help define DRA and the concepts on which it is based and allow glimpsing the way forward for future and enhanced DRA techniques.
... et al., 2004), risk-based maintenance (Bhandari, Arzaghi, Abbassi, Garaniya, & Khan, 2016;Khan & Haddara, 2004), and inherent safety approach (Baalisampang, Khan, Garaniya, Chai, & Abbasi, 2016;Heikkil€ a, 1999;Tugnoli, Khan, Amyotte, & Cozzani, 2008). Additionally, accident scenario modeling has been used extensively in safety management and accident prevention because it not only provides Adapted from Rouhiaiuen, V. (1990). ...
... MARK of the system, with minimizing the maintenance cost. Over the last decade, risk-based maintenance methods have attracted a significant attention in the process and offshore industry, since they provide a cost-effective tool to reduce the probability of failure in the structures and associated consequences [1,17,18]. Dey [5] developed a risk-based model using the Analytic Hierarchy Process (AHP) to identify the risk factors that influence failure of petroleum pipelines. Dey asserted that the developed technique can assist in reducing the cost of maintenance although it does not totally eliminate subjectivity. ...
Article
Research and development in the field of risk-based maintenance of offshore structures has recently attracted large attention due to the significant level of accident risk and the cost associated with maintenance in such remote facilities. The uncertainties associated with the deterioration of these facilities require a sound decision making methodology for maintenance planning. This paper presents a dynamic risk-based methodology for maintenance scheduling of subsea pipelines subjected to fatigue cracks. The developed method can assist the asset managers to select the optimum approach for mitigating the consequences of failure while minimizing the maintenance costs. A Bayesian network is developed to model the probabilistic deterioration process and then it is extended to an influence diagram for estimating the expected utility of each decision alternative. Observation of damage state is included in the model to enhance decision making capacity. To demonstrate the applicability of the methodology, three cases with different fatigue crack incidents on a pipeline are considered. Based on the monitoring results, the model is able to determine whether the maintenance should be performed or not. The economic risk associated with maintenance is also minimized by suggesting the optimum maintenance technique among multiple possible methods such as welding or major repair.
... The consequences also can be represented with nodes in the networks. The consequence analysis can be performed by determining the damage radii (the radius of the area which damage would occur, property damage and toxic effects, which was presented by Khan and Haddara (2004b). Leoni et al. (2019) applied the BN approach on the riskbased maintenance model for a Natural Gas Regulating and Metering Station, after BahooToroody et al. (2019). ...
Article
The operational performance of a chemical process plant highly depends on the assets' condition and maintenance practices. As chemical processes are highly complex systems, increasing the risk frequencies and their interactions, the maintenance planning becomes crucial for stable operation. This paper provides a critical analysis of the recently developed approaches for asset maintenance approaches in the chemical industry. The strategies include corrective maintenance, time-based, risk-based, condition-based and opportunistic maintenance. Various methods on selecting the optimal maintenance strategy are discussed as well. This paper also evaluates reliability issues in chemical plants and integrated sites encompassing the maintenance optimisation. Several directions for potential future improvements are proposed based on this analysis, as follows: (i) potential study of exploiting production or other opportunities to postpone or conduct earlier maintenance; (ii) joint optimisation of spare part ordering strategy and data-driven maintenance planning study is needed; (iii) fault propagation modelling of structural dependent units to facilitate proper maintenance planning; (iv) a framework or tool that consider quantitative and qualitative time-variant data inputs is lacking for business-informed asset maintenance.
... Based on Liu et al. (2015); Hokstad et al. (2010). Khan and Haddara (2004), Krishnasamy et al. (2005) and Haddara et al. (2008) showed that splitting a complex system into manageable units facilitates the decision makers to focus on the subsystems and components whose failures might substantially affect the system availability, result in economic loss, compromise safety and generate environmental impacts. ...
Article
Facilities life extension has caught the attention among the capital-intensive industries, like oil and gas. By extending the life cycle of the industrial assets, a wide range of benefits is obtained, comparing with other life ending management strategies. This article first contextualizes the implementation of the life extension concept in the oil and gas industry, showing global data about life extension. Despite the importance of the ageing process, due to its great economic impact and the risk it poses to the production sector, regulatory entities, even in countries more advanced in that sector or that have already experienced the extension process, developed only superficial material about the topic without defining a structured methodology for the assessment of the possibility of useful life extension. The available references do not allow a comprehensive analysis of that possibility, which highlights the importance the methodology proposed. Thus, this article proposes a guideline for the life extension process management, strengthening a framework containing the main evaluation stages, aiming to facilitate the analysis of issues related to ageing and to support the decision-making process. Lastly, real case studies regarding current life extension processes submitted to the Brazilian regulatory body were evaluated against the proposed framework stages, evidencing their lack of necessary details to support the decision-making. Upon the realization that the real cases identified do not allow for the assessment of the contribution and adequacy of the proposed framework in its entirety, the same was also applied to a hypothetical case. The latter was developed based on facts reported by a major operator in Brazil. The result was the determination that the use of the proposed methodology transformed the assessment of the possibility of life extension into a systematic and transparent process, leading to easier and better-founded decision-making procedures, and improving the management of the asset during its extended life.
... Maintenance is one of the most vital operations to maintain the desired profitability of the process and to optimize the life cycle cost by increasing the availability and reliability of the system [19]. ...
Article
Chemical process industries (CPIs) work with a variety of hazardous materials in quantities which have the potential to have large health, environmental and financial impacts and as such are exposed to the risk of major accidents. The experience with accidents in this domain shows many cases which involve complex human-machine interactions. Human Reliability Analysis (HRA) has been utilized as a proactive approach to identify, model, and quantify human error highlighted as the leading cause of accidents. Consequently, researchers have actively worked on enhancing process safety and risk engineering since the '70s. However, despite its importance and practical implications for improving human reliability, there has not been a review of human reliability related to processing systems. The present study is aimed at presenting a systematic attempt to identify the needs, gaps, and challenges of HRA in CPI. An in-depth analysis of the literature in Web of Science core collection and Scopus databases from 1975 to August 2020 is conducted. This analysis focuses on human factors in three critical elements of CPIs: maintenance operations, emergency operations, and control room operations. The analysis synthesizes the theoretical and empirical findings, shedding light on the strengths and shortcomings of current literature and identifying research opportunities. A comparison of HRA in CPIs is undertaken with nuclear power plants (NPPs) to better understand the current stage of research and research challenges and opportunities.
... Bakım planlamasına bütünleşik yönetim anlamında yeni bir vizyon kazandıran, sistemlerdeki risk seviyelerini bir kriter olarak kullanan ve son yıllarda araştırmacıların ilgisinin yoğunlaştığu risk tabanlı bakım stratejisi ise 90'lı yıllarda ortaya çıkmıştır. Harnyl [7], Khan ve Haddara [8,9] ile Arunraj ve Maiti [10] risk tabanlı bakım stratejisini kimyasal üretim tesislerinin; Apeland ve Aven [11], Bertolini, vd. [12] ve Kerhavarz, vd. ...
... In this section, application of the proposed risk estimation is applied on two parts (Mixer 100 and Valve 101) of high pressure separator (Khan and Haddara 2004). The assumption made for this application is the result of the qualitative assessment for the likelihood of the risk is equal and therefore is not discussed in this application. ...
Article
Maintenance department within petroleum industry seek to increase equipment safety by means of reducing the occurrence of the failure and its undesirable consequences. In this study, a risk assessment model is proposed, which includes the likelihood of the risk and the consequences of failure. A new mathematical equation is proposed to assess the likelihood of risk and identify the optimum inspection interval. In addition, modified mathematical equation to evaluate consequences of risk which allow more generalization and accuracy of weighing the possible losses (performance, financial, ecology and human) is developed. The results demonstrate an improvement at the assessment of the probability of risk and provide better understanding of the impact of the risk on the major identified areas within the petroleum industry.
... The developments in maintenance management are in continuous changing due to complex systems and equipment [1]. Fuzzy data is being applied for modelling complex systems [2]. ...
Chapter
Ships can navigate several months on sea. Maintenance and supply are the base for ship successful navigation and mission. Every type of equipment should have a maintenance plan. If it is a corrective maintenance plan, some risks are inherent. This study pursues a Management Maintenance System considering minimal costs, where the best equipment availability and performance is the objective. For this work, an air compressor was chosen as study case from a ship and considered three study stages. The first stage consisted of the definition of evaluation criteria and its meaningfulness. The data treatment from the first stage can provide enough information to define the second stage’s maintenance methodology decision. Also, the decision-making itself based on the process is the third stage. The development of decision-making methodology for maintenance management was based on a Fuzzy method considering a Risk-Based Maintenance on ship equipment.
... The FTA technique has been extensively used within numerous industrial systems aimed at diverse applications; for instance, the assessment of system safety in a nuclear reactor and gas distribution systems [33,40]; the diagnosis and prognosis of faults/failures in electric power, electronic components, pipelines, and aerospace [41,42]; the implication of maintenance tasks in medical devices, mining, chemical processes, and mechanical systems [36,37,43,44]; and the analysis of FP values in automotive, chemical, and petrochemical processes [39,45,46]. Despite many advantages and the successful feedback of the FTA technique to estimate the FP values, the technique includes some limitations, such as the simplification of the model due to the system's complexity and the lack of knowledge about the system's behavior; an assumption of the independence of events; and the possibility of human error while specifying the logical structure of fault trees and the presence of the redundant or common cause failures [28,29]. ...
Preprint
Process integrity, insufficient data, and system complexity in automotive manufacturing sector are the major uncertainty factors to predict Failure Probability (FP), which are very influential in achieving a reliable maintenance program. To deal with such uncertainties, this study proposes a Fuzzy-Fault Tree Analysis (FFTA) approach as proactive knowledge-based technique to estimate the FP towards a convenient maintenance plan in automotive manufacturing industry. Besides, in order to enhance the accuracy of the FFTA model in predicting FP, the effective decision attributes, such as experts' trait impacts, scales variation, and assorted membership and defuzzification functions were investigated. Moreover, due to the undynamic relationship between the failures of complex systems in the current FFTA model, a Bayesian Network (BN) theory was employed. The results of FFTA model revealed that the changes in various decision attributes were not statistically significant on FP variation while BN model considering conditional rules to reflect the dynamic relationship between failures had more impact on predicting FP. After all, the integrated FFTA-BN model was used in the optimization model to find the optimal maintenance intervals according to estimated FP and total expected cost. As a case study, the proposed model was implemented in a fluid filling system in an automotive assembly line. The FPs of the whole system and its three critical subsystems such as filling headset, hydraulic-pneumatic circuit, and the electronic circuit were estimated as 0.206, 0.057, 0.065, and 0.129, respectively. Moreover, the optimal maintenance interval for the whole filling system considering total expected costs was determined as 7th with 3286 $ during 5000 hours of operation.
... The FTA technique has been extensively used within numerous industrial systems aimed at diverse applications; for instance, the assessment of system safety in a nuclear reactor and gas distribution systems [33,40]; the diagnosis and prognosis of faults/failures in electric power, electronic components, pipelines, and aerospace [41,42]; the implication of maintenance tasks in medical devices, mining, chemical processes, and mechanical systems [36,37,43,44]; and the analysis of FP values in automotive, chemical, and petrochemical processes [39,45,46]. Despite many advantages and the successful feedback of the FTA technique to estimate the FP values, the technique includes some limitations, such as the simplification of the model due to the system's complexity and the lack of knowledge about the system's behavior; an assumption of the independence of events; and the possibility of human error while specifying the logical structure of fault trees and the presence of the redundant or common cause failures [28,29]. ...
Article
Full-text available
Process integrity, insufficient data, and system complexity in automotive manufacturing sector are the major uncertainty factors to predict Failure Probability (FP), which are very influential in achieving a reliable maintenance program. To deal with such uncertainties, this study proposes a Fuzzy-Fault Tree Analysis (FFTA) approach as proactive knowledge-based technique to estimate the FP towards a convenient maintenance plan in automotive manufacturing industry. Besides, in order to enhance the accuracy of the FFTA model in predicting FP, the effective decision attributes, such as experts' trait impacts, scales variation, and assorted membership and defuzzification functions were investigated. Moreover, due to the undynamic relationship between the failures of complex systems in the current FFTA model, a Bayesian Network (BN) theory was employed. The results of FFTA model revealed that the changes in various decision attributes were not statistically significant on FP variation while BN model considering conditional rules to reflect the dynamic relationship between failures had more impact on predicting FP. After all, the integrated FFTA-BN model was used in the optimization model to find the optimal maintenance intervals according to estimated FP and total expected cost. As a case study, the proposed model was implemented in a fluid filling system in an automotive assembly line. The FPs of the whole system and its three critical subsystems such as filling headset, hydraulic-pneumatic circuit, and the electronic circuit were estimated as 0.206, 0.057, 0.065, and 0.129, respectively. Moreover, the optimal maintenance interval for the whole filling system considering total expected costs was determined as 7th with 3286 $ during 5000 hours of operation.
Article
Due to high acquisition costs of new units, defence products can be subjected to life extension processes, sometimes not previously planned during their life cycle. These processes are characterised by widespread maintenance tasks and they can be denominated as major overhauls. The main objective of this paper is to propose a methodology to aid the major overhaul technical management. In general, the major overhaul defines the scope of maintenance and modernisation. Main problems about maintenance are managed by risk-based decision-making for determination of replacement rules and quantities of spares. The need for redesign of parts that interacts with the upgraded subsystems is evaluated by design structure matrix and a HAZOP-based analysis aiming at achieving product performance requirements. The proposed method is a support tool to the major overhaul manager, not replacing technical methodologies that are specific to each branch of the overhauled product. The proposed method was applied to a major overhaul project of an armoured personnel carrier. The results enabled a better characterisation of detailed design, analysing risks in the context of maintenance and modernisation aiming at controlling modernised product life cycle.
Article
Offshore oil and gas assets are highly complex structures comprising of several components, designed to have a lifecycle of 20–25 years of working under harsh operational and environmental conditions. These assets, during their operational lifetime, are subjected to various degradation mechanisms such as corrosion, erosion, wear, creep and fatigue cracks. In order to improve economic viability and increase profitability, many operators are looking at extending the lifespan of their assets beyond the original design life, thereby making life extension (LE) an increasingly critical and highly-discussed topic in the offshore oil and gas industry. In order to manage asset aging and meet the LE requirements, offshore oil and gas operators have adopted various approaches such as following maintenance procedures as advised by the original equipment manufacturer (OEM), or using the experience and expertise of engineers and inspectors. However, performing these activities often provides very limited value addition to operators during the LE period of operation. This paper aims to propose a systematic framework to help operators meet LE requirements while optimizing their cost structure. This framework establishes an integration between three individual life assessment modules, namely: condition assessment, remaining useful life (RUL) prediction and LE decision-making. The benefits of the proposed framework are illustrated through a case study involving a three-phase separator system on a platform which was constructed in the mid-1970s in West Africa. The results of this study affirm the effectiveness of this framework in minimizing catastrophic failures during the LE phase of operations, whilst ensuring compliance to regulatory requirements.
Article
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Statistics on accidents at work, particularly in Morocco, remain worryingly high. This situation raised a general awareness in the country and many decisions have been taken and corrective actions have been elaborated in order to enhance enterprise risk management maturity. This maturity is based on several key factors including maintenance.In this paper we propose a methodology to mitigate and control maintenance generated risks which in turn will allow enterprises to enhance their maturity in risk management.
Conference Paper
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Equipment breakdown due to unavailability of spare parts is really disastrous in plant maintenance. The failure increase the cost of repair and production downtime. Therefore, it is important to understand the maintenance and inventory function in order to ensure the plant operate accordingly. Moreover, it is necessary for the plant maintenance to balance the issue of shortage and excess of inventory in plant maintenance. In view of this situation, the spare parts become a critical matters and it is good starting point to tackle the issues from looking at the perspective of spare parts inventory risk. This paper describes the development of risk technique for plant maintenance decision making purposes using the Shortage and Excess Impact Table. It also used the Breakdown Probability Table to quantify the risk for the spare part failure.
Article
The transition from time‐based inspection to risk–based inspection (RBI) in Malaysian industry began in June 2014 with the gazette of Factories and Machinery (Special Scheme of Inspection) (Risk‐Based Inspection) Regulations 2014 (SSI 2014). Under the new regulations, owners shall express their commitment and provide proof of their ability to ensure safety, integrity, and operability of relevant equipment. The regulation does not prescriptively mention methods to implement the RBI approach, but does spell out minimum requirements. Upon successful demonstration of compliance to the authority, the Certificate of Fitness of pressurized equipment may be extended to maximum 72 months. This paper aims to establish the benefits which may accrue from the adoption of RBI approach and ascertain the potential difficulties associated with the implementation of this approach. The paper first presents a review of the literature, establishing the major reasons for, and the benefits of, RBI implementation. This is followed by the results of a Malaysian survey on the implementation of RBM approach. An audit was conducted in the Malaysian petrochemical and chemical industries in April 2016. The audit results highlight the reasons for and benefits of implementing RBI. The paper concludes with a discussion and recommendations for the implementation of the RBI approach. © 2017 American Institute of Chemical Engineers Process Saf Prog, 2017
Chapter
Basic concepts associated with equipment reliability and their application to modern engineering systems are presented in this chapter, which is intended to provide readers with the information needed to understand the methods used in the rest of the book. In engineering systems, in addition to reliability requirements, safety during operation is typically a design requirement. Safety analysis is usually executed based on risk analysis concepts and techniques, such as quantitative risk analysis, fault tree analysis, and failure mode and effects analysis, which are examined in this chapter. Finally, maintenance topics are discussed in detail, including both corrective maintenance and preventive maintenance, since modern engineering systems must rely on maintenance actions to support their performance throughout their entire operational life.
Article
Risk‐based inspection (RBI) is a tool which helps ensure safe and economically viable operation. To benefit from an RBI system, the factors that affect its implementation need to be studied. This research focuses on identifying and ranking the critical success factors (CSFs) of RBI. Based on the literature review of RBI, an initial list of 28 potential CSFs was identified and complied. These CSFs were then grouped into eight factor headings according to RBI/RBM, RBIM and risk assessment process. A survey was conducted to assess and prioritizes the degree of influence of those success factors on RBI systems, while determining whether these CSFs do indeed play a critical role in the successful implementation of RBI systems as perceived by the respondents. Samples were collected to confirm the identified CSFs. The findings show that the most influential factor is “Data Collection,” and while “RBI Estimation” is the most critical factor heading in the implementation of RBI. Additionally, the findings also show that all CSFs identified are critical and relevant for Malaysian industries. © 2018 American Institute of Chemical Engineers Process Saf Prog, 2018
Article
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Purpose The purpose of this paper is to develop a decision support tool for risk-based maintenance scheduling for a large heavily equipped gas sweetening unit in a Liquefied Natural Gas (LNG) plant. Two conflicting objectives, i.e., total maintenance cost and the reliability, are considered in the tool. The tool is tested with the real plant data and suggests several Pareto-optimal schedules for a decision maker to choose from. The financial impacts are assessed. Design/methodology/approach A bi-objective scheduling optimization model is developed for maintenance scheduling using a risk-based framework. The model is developed integrating genetic algorithm and simulation-based optimization to find Pareto-optimal schedules. The model delivered true Pareto front optimal solutions for given plant-specific data. The two conflicting objectives: the minimization of total expenditures incurred on maintenance-related activities and improving the total reliability are considered. Findings For large and complex processing facilities such as LNG plant, a shutdown of facility generates a significant financial impact, resulting in millions of dollars in production loss. The developed risk-based equipment selection strategy helps to minimize such an event of production loss by generating a thorough maintenance strategy for inspection, repair, overhaul or replacement schedule of the unit without initiating the shutdown. The proposed model has been successfully applied to obtain an optimize maintenance schedule for a gas sweetening unit. Research limitations/implications A future work may consider the state-dependent models for various failure modes that will result in obtaining a better representation of the model. The proposed scheduling can further be extended to multi-criteria scheduling including availability, resource limitation and inflationary condition. A comparative analysis with other meta-heuristic techniques such as harmony search algorithm, tabu search, and simulated annealing will further help in confirming the schedule obtained from this application. Practical implications Maintenance scheduling using a conventional approach for special equipment generally does not consider the conflicting objectives. This research addresses this aspect using a bi-objective model. The usefulness of risk-based method is to assist in minimizing the financial and safety risk exposure to the operating companies, but some variation in results is expected due to varying risk matrix for different organizations. Social implications Managing two objectives, i.e., minimizing the cost of maintenance-related activities, while at the same time maximizing the overall reliability dramatically, helps in mitigating adverse safety and financial risk due to fires, explosions, fatality and excessive maintenance cost. Originality/value Research develops a decision support tool for managing conflicting objectives for an LNG process. This research highlights the impact of utilizing the simulation-based approach coupled with risk-based equipment selection for complex processing unit or plant maintenance scheduling optimization.
Article
This paper describes the design and the implementation of a process of asset criticality analysis for Distribution Network Services Providers (DNSP), also named Network Utilities. The proposed method is based on two points: (i) the elicitation of business-value factors, and (ii) the risk-based evaluation of assets, considering potential impacts of their failures on network value. Thus, it provides the capability to take maintenance management decision in terms of value and risk, considering the whole network under unique and homogeneous criteria. A hierarchy of assets ranked will come out of this process, which represents a fundamental result serving as input of the subsequent steps of the asset management process, including maintenance and renewal/reinvestments decisions. The proposed methodology is aligned with ISO 55000 family of standards approach, and therefore it can be understood as a practical asset management tool. Specific attention is paid to particular network utilities issues, characterizing assets in these companies, and the services that they provide (topology influence, reputational impact, operational losses, etc.). In addition to this, high requirements established by the Service Level Agreements (SLA), that are characteristics of network services contracts, make this method especially suitable in this application, considering in an overall way all these key aspects, providing great advantages for managing network utilities. In order to illustrate method applicability, an example extracted from a real telecommunication network use case is included.
Article
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A maioria das reservas brasileiras de petróleo na atualidade encontra-se em campos marítimos (PETROBRAS, 2014), o que torna desafiadora a logística de atendimento às atividades da indústria de petróleo e gás no ambiente offshore. Os desafios se estendem a todas as áreas do conhecimento humano que fazem parte do cenário da região de produção. Naturalmente, os desafios serão proporcionalmente maiores onde há mais atividades. A Bacia de Campos, em função da sua representatividade no contexto da produção nacional de petróleo, vivencia esta realidade e uma das atividades a superar os desafios que se apresentam à cada dia é a de manutenção dos itens de telecomunicações. Com a missão de oferecer e garantir a comunicação de pessoas, aplicativos e processos às unidades que operam a mais de 100 Km da costa, os órgãos internos atuam fortemente na melhoria dos processos de manutenção do diversificado parque de telecomunicações instalado nas plataformas. Dentre os esforços empreendidos encontra-se a mnutenção preventiva, a qual atualmente é realizada de forma cíclica, seguindo cronogramas pré-estabelecidos para cada rede ou sistema.Com o crescimento do número de plataformas e o aumento das distâncias em direção à região do pré-sal, a periodicidade dos ciclos de manutenção preventiva de telecomunicações pode ser afetada e decisões de priorização deverão ser tomadas na direção da escolha da plataforma a receber as ações de prevenção. Como efetuar esta priorização? Quais critérios deverão ser considerados ? Como estes critérios se relacionarão entre si para a tomada de decisão ? Este trabalho tem por objetivo responder a estas questões através de consultas à literatura, consultas a especialistas em telecomunicações no ambiente offshore e a subsequente aplicação da metodologia de Lawshe (1975), largamente utilizada no meio acadêmico para a seleção de itens pesquisados. Concluída esta etapa, os critérios selecionados servirão de base para aplicação de um método de Auxílio Multicirtério à Decisão no processo decisório numa próxima fase, a qual não está incluída no escopo deste artigo. Palavras-chave: Telecomunicações; Manutenção preventiva; Auxílio Multicritério à Decisão.
Chapter
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Modern business environment can tolerate no failures, especially involving unscheduled shutdowns, environmental contamination, individual injuries, and human fatalities.
Article
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Polygonal wear is one of the most critical failure modes of high-speed train wheels that would significantly compromise the safety and reliability of high-speed train operation. However, the mechanism underpinning wheel polygon is complex and still not fully understood, which makes it challenging to track its evolution of the polygonal wheel. The large amount of data gathered through regular inspection and maintenance of Chinese high-speed trains provides a promising way to tackle this challenge with data-driven methods. This article proposes a data-driven approach to predict the degree of the polygonal wear, assess the reliability of individual wheels and the health index of all wheels of a high-speed train for maintenance priority ranking. The synthetic minority over-sampling technique—nominal continuous is adopted to augment the maintenance dataset of imbalanced and mixed features. The autoencoder is used to learn abstract features to represent the original datasets, which are then fed into a support vector machine classifier. The approach is coherently optimized by tuning the model hyper-parameters based on Bayesian optimization. The effectiveness of our proposed approach is demonstrated by the wheel maintenance data obtained from the year 2016 to 2017. The results can also be used to support practical maintenance priority allocation.
Article
With the development of modern automatic control systems, chemical accidents are of low frequency in most chemical plants, but once an accident happens, it often causes serious consequences. Near-misses are the precursor of accidents. As the process progresses, near misses caused by abnormal fluctuation of process variables may eventually lead to accidents. However, variables that may lead to serious consequences in the production process cannot update the risk in the life cycle of the process by traditional risk assessment methods, which do not pay enough attention to the near misses. Therefore, this paper proposed a new method based on Bayesian theory to dynamically update the probability of key variables associated with process failure risk and obtain the risk change of the near-misses. This article outlines the proposed approach and uses a chemical process of styrene production to demonstrate the application. In this chemical process, the key variables include flow rate, liquid level, pressure and temperature. In order to study the dynamic risk of the chemical process with consideration of near misses, according to the accumulated data of process variables, firstly the abnormal probability of the variables and the failure rate of safety systems associated with the variables were updated with time based on Bayesian theory. On the basis of the dynamic probability of key process variables, an event tree of possible consequences caused by variable anomalies was established. From the logical relationship of the event tree, the probability of different consequences can be obtained. The results show that the proposed risk assessment method based on Bayesian theory can overcome the shortcomings of traditional analysis methods. It shows the dynamic characteristics of the probability of different near misses, and achieves the dynamic risk analysis of chemical process accidents.
Article
In safety, understanding of risk and reliability is generally not possible without reference to time. For example, regarding the risk of some activity or situation, focus is on what might happen in future time in relation to the potential for negative outcomes or consequences. Currently, several definitions of risk are available, indicating a lack of consensus on how to define this, also within international standards. A common characteristic, is that neither of the definitions are explicitly capturing time. In contrast, the concept of reliability is explicit on this, focussing on failure-free performance for a given time interval, indicating a discrepancy and inconsistency between the concepts. There are different temporal aspects and key argumentation for and against inclusion of time in the definition of risk. We discuss the relevance to the understanding and interpretation, and conclude, that it is insufficient to assume time strictly implicitly as part of the possible consequences. As for the reliability concept, the element of time matters to the understanding of risk as a concept, and contributes to a more specific description of risk. A more appropriate definition of this concept that allows for this element to be explicitly captured is suggested in this article.
Article
Vapor cloud explosions (VCEs) have been considered as a major hazard in petrochemical industry, accompanying with wide-ranging impact and huge destruction. The existing methods are incapable to make a rapid and accurate estimation when considering multi-factor coupling effects. Therefore, this study proposed a novel methodology of fusing numerical simulation (NS) with neural network (NN) technique for the prediction of explosion consequences. First, 6 parameters of VCEs influencing overpressure are selected as variables of a database. A CFD method is employed for simulating VCEs in a chemical site, by which sufficient blast data are generated. After the architecture of a NN model is determined, data on three generic VCEs are extracted for further model training process. A progressive training method is adopted to develop a general prediction model. Furthermore, data derived from ongoing simulation results are imported into the model for its constant self-improvement. The output of the well-trained model is subsequently transformed into a probabilistic function to assess the domino effect. The integrating NS with NN approach provides an accurate and efficient way to predict the blast effects, which can support more scientific rescue decision-making. Finally, the proposed model is applied to a case study for illustration.
Book
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Tujuan utama buku ini dibuat, dalam rangka memperkaya wawasan ilmiah dosen dalam kegiatan meneliti dan mengajar serta untuk memotivasi dosen agar terus menulis buku teks yang dihasilkan sebagai sarana belajar dan pendalaman ilrnu bagi mahasiswa di Universitas Negeri Jakarta. Selain itu untuk memfasilitasi dan memberikan dukungan kepada dosen/peneliti di lingkungan Universitas Negeri Jakarta yang memiliki naskah buku teks pembelajaran yang diturunkan dari penelitian multi disiplin ilmu yang belum diterbitkan, maka Universitas Negeri Jakarta mernfasilitasi Program dari Dit.Litabmas Dirjen Dikti dalam penyediaan dana bagi penyempurnaan, konsultasi, penggandaan naskah akhir dan hibah bagi penulis sebelum diterbitkan oleh penerbit. Buku ajar sebagai buku pegangan untuk suatu mata kuliah yang ditulis dan disusun oleh pakar di bidangnya dan memenuhi kaidah buku teks serta diterbitkan secara resmi dan disebar luaskan. Upaya penulisan ini dimaksudkan untuk meningkatkan mutu dan efektivitas kegiatan pembelajaran melalui penyediaan buku ajar/buku teks yang bermutu dan relevan terkait dengan matakuliah di Program D3 Transportasi Fakultas Teknik Universitas Negeri Jakarta. Selain itu untuk pengembangan karier dan profesi sebagai dosen dan meningkatkan kualitas dan kuantitas karya ilmiah atau publikasi ilmiah. Fasilitas Pelabuhan meliputi wilayah daratan dan pelabuhan di wilayah perairan baik fasilitas pokok atau penunjang. Kinerja utama dalam sebuah fasilitas pelabuhan sangat tergantung bagaimana program pemeliharaan dan perawatan fasilitas berjalan secara optimal. Oleh karena itu maka dengan adanya buku ini dharapkan dapat memberikan pemahaman tentang dasar-dasar pemeliharaan dan perawatan fasilitas pelabuhan bagi mahasiswa di Diploma 3 Transportasi, Fakultas Teknik UNJ. Harapan lainnya dapat dijadikan sebagai pendamping dalam pelaksanaan pekerjaan pemeliharaan dan perawatan untuk merencanakan perawatan fasilitas pelabuhan baik di wilayah daratan maupun perairan untuk mahasiswa S1 dan bahkan S2 dan S3 yang akan melakukan riset-riset terkait dengan fasilitas pelabuhan sebagai referensi tambahan serta para praktisi di industry konstruksi. Buku ini disusun berdasarkan referensi yang terkait dengan pemeliharaan dan perawatan secara umum dan fasilitas pelabuhan serta regulasi di sistem transportasi laut di Indonesia.
Article
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Introduction: Risk-based inspection is a powerful tool provided by the American Petroleum Institute in order to respond to the needs of the process industries. The main focus of this method is on inspection, integrity management, maintenance, as well as reduction of the probability of failure. The purpose of this study was to conduct the risk-based inspection technique and critical success factors in its implementation to improve risk and process safety based management systems. Methods: In this review study, we first listed the keywords based on the research title including Critical Success Factors, risk assessment, process safety, corrosion management, inspection Plan, failure mechanism, Risk Based Inspection, Risk Based Maintenance, Risk-based Integrity Management, and Asset Integrity Management . Later, each term was searched specifically and without time limit in the internal and external databases of Science Direct, PubMed, Google Scholar, SID, Google Search, Magiran, Civilica, and Scopus. Result: A systematic review of various studies showed that critical success factors provided the necessary context for the implementation of a risk-based inspection process in the process industries and were essential factors for the effective implementation of the RBI method. Conclusion: By analyzing the results of the studies we found that identifying CSFs can improve the effective implementation of RBI in industries and guarantee the benefits mentioned for this method. Moreover, the engineering and accurate implementation of risk-based inspection method will lead to the best implementation of management systems based on the risk and process safety and its improvement.
Article
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Since gas plants are progressively increasing near urban areas, a comprehensive tool to plan maintenance and reduce the risk arising from their operations is required. To this end, a comparison of three Risk-Based Maintenance methodologies able to point out maintenance priorities for the most critical components, is presented in this paper. Moreover, while the literature is mostly focused on probabilistic analysis, a particular attention is directed towards consequence analysis throughout this study. The first developed technique is characterized by a Hierarchical Bayesian Network to perform the occurrence analysis and a Failure Modes, Effects and Criticality Analysis to assess the magnitude of the adverse outcomes. The second approach is a Quantitative Risk Analysis carried out via a software named Safeti. Finally, another software called Synergi Plant is adopted for the third methodology, which provides a Risk-Based Inspection plan, through a semiquantitative risk analysis. The proposed study can assist asset manager in adopting the most appropriate methodology to their context, while highlighting priority components. To demonstrate the applicability of the approaches and compare their rankings, a Natural Gas Regulating and Measuring Station is considered as case study. The results showed that the most suited method strongly depends on the available data.
Thesis
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Poorly maintenance scheduling and the resulting downtime are costly. Deliver maximum performance while minimising costs and risks over the whole life of engineering systems required a developmental transition from traditional maintenance strategies to smart predictive maintenance. This PhD study aimed at maximising the value realised from complex engineering assets and systems. To this end, statistical modelling and machine learning were established to problems in intelligent maintenance operations, characterized by data-driven innovations. The outcome of this study are far better avoidance of failures, significantly reducing whole-life costs, better running of assets, increasing the resilience of components while no inappropriate risk has to be taken.
Article
Purpose The purpose of this paper is to analyze the reliability of the quantitative risk model used for planning inspection and maintenance activities. The objective is to critically discuss the factors that contribute to the probability and consequence of failure calculations. Design/methodology/approach The case study conducted using one of the most widely deployed risk models in the oil and gas industry where a full assessment was performed on an offshore gas producing platform. Findings The generic failure frequencies used as the basis for calculating the probability of failure are set at a value representative of the refining and petrochemical industry's failure data. This failure database does not cover offshore. The critical discussion indicated the lack of basis of the coefficient of variances, prior probabilities and conditional probabilities. Moreover, the risk model does not address the distribution of thickness measurements, corrosion rates and inspection effectiveness, whereas only overall deterministic values are used; this requires judgment to determine these values. Probabilities of ignition, probabilities of delayed ignition and other probabilities in Level 1 event tree are found selected based on expert judgment for each of the reference fluids and release types (i.e. continuous or instantaneous). These probabilities are constant and independent of the release rate or mass and lack of constructed model. Defining the release type is critical in the consequence of the failure methodology, whereas the calculated consequences differ greatly depending on the type of release, i.e. continuous or instantaneous. The assessment results show that both criteria of defining the type of release, i.e. continuous or instantaneous, do not affect the calculations of flammable consequences when the auto-ignition likely is zero at the storage temperature. While, the difference in the resulted toxic consequence was more than 31 times between the two criteria of defining the type of release. Research limitations/implications There is a need to revamp this quantitative risk model to minimize the subjectivity in the risk calculation and to address the unique design features of offshore platforms. Originality/value This case study critically discuss the risk model being widely applied in the O&G industry and demonstrates to the end-users the subjectivity in the risk results. Hence, be vigilant when establishing the risk tolerance/target for the purpose of inspection and maintenance planning.
Article
Inspection methodologies have evolved in the past decades to explore optimal interval and inspection methods. The American Petroleum Institute has published several standards such as API-510, API 653, API 570 and API-580 to assist in determining inspection intervals based on equipment life, consequences of failure, degradation rate, and environmental impact. The most recent approach is the Risk Based Inspection, API-580 and API-581. The underlying assumption of this approach is that risk remains acceptable between two planned inspection or maintenance intervals. This condition may not hold true in a complex, fast-changing or degrading engineering system. This study presents an innovative method to assess risk for a dynamically changing system based on the system parameters that are continuously monitored. The calculated dynamic risk can be used to plan optimal inspection and maintenance intervals more efficiently. The proposed method is tested on several possible combinations of an engineering system. Efforts are also made to align and integrate the proposed method with API-581. This would help to implement a more accurate approach while maintaining the required industry standard to ensure safe operation with low uncertainty.
Article
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Correspondence concerning this paper should be addressed to Professor S. A. Abbasi, Centre for Pollution Control and Energy Technology, Pondicherry University, Kalapet, Pondicherry 605 014, India.
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Posing various possible incidents - rather than just the worst-case one - illuminates those that are really important and are most likely. Such knowledge can enhance safety and planning for emergencies.
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Traditionally, the severity of accidents in the chemical process industries has been gauged on the basis of the human lives lost1-5. However, factors such as loss of assets, contamination of the surroundings, and the resultant trauma also contribute to a very large extent towards the adverse impacts of such accidents. We have developed Accident Hazard Index (AHI) as a new system for a comprehensive yet rapid assessment of the damage caused by accidents in the chemical process industries. The index can also be used to assess the impacts of accidents likely in a yet-to-be-commissioned industry on the basis of site characteristics and the industry’ s process and operational details; the index thus enables one to choose between possible sites for setting up a new industry.
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Due to the risks associated with the consequences and the probability of failure of high energy pressure system and the probability of occurrence, in some cases, additional measures must be taken to protect life and property. The proposed ASME HPSC Section 6000 {open_quotes}Hazardous Release Protection{close_quotes} addresses this concern, requiring a hazard analysis and possible mitigating features to reduce risk to life and property to a tolerable level. The non-mandatory section (Appendix D) provides a guide and reference with respect to the mechanics of phenomena, hazard evaluation, hazard mitigation, risk assessment, and on other aspects of controlling risk. 35 refs., 13 figs., 1 tab.
Article
A new software package for conducting rapid risk assessment (RRA) in chemical process industries and the system of methodologies on which it is based are described. The objectives behind the development of the package are to achieve greater breadth and depth, sophistication, and user-friendliness in conducting RRA. In pursuit of these objectives we have incorporated in the package state-of-the-art models for generating accident scenarios and assessing their consequences. The package has been coded in C++ using the concepts of object-oriented programming to enhance the tool's speed of execution and ease of use. The paper also demonstrates the applicability of MAXCRED with an illustrative example of a RRA conducted with its assistance.
Article
In-service inspection and maintenance assessment of plant and equipment to reduce the risk of failure and hazardous release have been used for many decades as cost-effective procedures in concert with design, material selection, defect criteria, fabrication, and operation/use. Codes and standards have, more recently, sought to provide hazardous release protection as an additional means of reducing risk by means of criteria based on risk (event probability and consequences), including maintenance and inspection. These criteria use risk-based methods for prioritizing inspection and maintenance. In a power station or refinery, for example, the risk of unplanned shut-down is related to the failure or malfunction of a relatively small number of items. Risk-based maintenance and inspection allows efforts to be concentrated on items involving the highest risk, with a proportionate reduction in effort for low-risk items. Hence, base-load operating times can generally be increased, while maintaining the same or reduced level of risk. Maintenance and inspection inspection play a vital role to reduce risk by more accurately quantifying event probability. Where there is a possibility of high-risk catastrophic failure, the consequences and risk to personnel, environment and equipment can be rendered tolerable to negligible if appropriate protective systems are in place with reduced maintenance and inspection. This paper reviews several cases in which the authors have been involved and in which failures would have been prevented if proper risk assessment procedures had been in place or in which assessment of risk was made to prevent failure. [S0094-9930(00)02203-4].
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The overall objective of the maintenance process is to increase the profitability of the operation and optimize the total life cycle cost without compromising safety or environmental issues. Risk assessment integrates reliability with safety and environmental issues and therefore can be used as a decision tool for preventive maintenance planning. Maintenance planning based on risk analysis minimizes the probability of system failure and its consequences (related to safety, economic, and environment). It helps management in making correct decisions concerning investment in maintenance or related field. This will, in turn, result in better asset and capital utilization.This paper presents a new methodology for risk-based maintenance. The proposed methodology is comprehensive and quantitative. It comprises three main modules: risk estimation module, risk evaluation module, and maintenance planning module. Details of the three modules are given. A case study, which exemplifies the use of methodology to a heating, ventilation and air-conditioning (HVAC) system, is also discussed.
Article
This paper considers the application of one of the weighted risk indicators used by the Major Hazards Assessment Unit (MHAU) of the United Kingdom's Health & Safety Executive (HSE) in formulating advice to local planning authorities on the siting of new major accident hazard installations. In such cases the initial consideration is to be assured that the proposed installation would not be incompatible with existing land uses in the vicinity, as determined by the categorization of the existing populations and the estimated levels of individual risk which the proposed installation would impose upon them. An analysis of the consequences and likelihood of a single “worst case” event, coupled with MHAU's “Risk Integral,” is then undertaken. This enables the societal risk aspects of the proposal to be considered at an early stage and, in many cases, allows a prompt response. The paper describes the methodology and includes several case studies based on MHAU's day to day work which illustrate its use.
Article
A methodology has been developed to conduct probabilistic fault tree analysis during risk assessment in chemical process industries. The methodology is based on a system involving (a) development of fault tree, (b) determination of minimum cutsets or shortest pathways leading from initiating events (malfunctioning) to the top event (the major accident), (c) probability analysis, and (d) working out improvement index values. To this end techniques of Boolean algebra, structure moduling, analytical method of cutsets finding (top-to-bottom algorithm), Monte-Carlo simulation, optimization technique and fuzzy probability set have been used.We named the methodology Analytical -Simulation Methodology (ASM) and we developed a software package PROFAT (PRObabilistic fault tree analysis) to facilitate the use of the methodology in a rapid and eflective, yet user-friendly manner. PROFAT enables the user to find out, in an industry, (i) initiating events which may eventually lead to a major accideizt, (ii) shortest routes (minimum cutsets) a series of initiating events may take place while aiding each other in causing the accideizt. (iii) the probabilities of occurrence of such initintirig events, (iv) relative contributiom of each of the initiating events and, finally, (v) identfiing initiating events with the greatest potential to cause the top event (major accident) so that accident prevention strategies aud emergency preparedness plans can be focused on them.The noteworthy attributes of the system are: resilience towards lack of precision in the basic data, swift processing with moderate requirements of computation cupacity (sophistication of computers needed), ease of use, and direct1y utiliz-able output. The applicability of PROFAT has been denionstrated with a case study of a sulfolane manufacturing unit.
Article
Lately there has been an increasing focus on risk based maintenance optimization in the offshore industry prompted by new functional regulations on risk. In this paper we present alternative probabilistic frameworks for this optimization, using a Bayesian approach. Some key features of the frameworks are discussed, including uncertainty treatment and type of performance measures to be used.
Article
Fault tree analysis (FTA) is based on constructing a hypothetical tree of base events (initiating events) branching into numerous other sub-events, propagating the fault and eventually leading to the top event (accident). It has been a powerful technique used traditionally in identifying hazards in nuclear installations and power industries. As the systematic articulation of the fault tree is associated with assigning probabilities to each fault, the exercise is also sometimes called probabilistic risk assessment. But powerful as this technique is, it is also very cumbersome and costly, limiting its area of application. We have developed a new algorithm based on analytical simulation (named as AS-II), which makes the application of FTA simpler, quicker, and cheaper; thus opening up the possibility of its wider use in risk assessment in chemical process industries. Based on the methodology we have developed a computer-automated tool. The details are presented in this paper.
An overview of the proposed ASME Code BPTC/HPSC SC6000, Hazardous release protection
  • S J Brown
S.J. Brown, An overview of the proposed ASME Code BPTC/HPSC SC6000, Hazardous release protection, Process Safety Symp, 1994, Vol. 1, Feb.-Mar.
American Society of Mechanical Engineers Code Committee SC6000, Hazardous release protection
American Society of Mechanical Engineers (ASME), American Society of Mechanical Engineers Code Committee SC6000, Hazardous release protection, ASME, New York, 2000.
Loss prevention in CPI
  • F P Lees
F.P. Lees, Loss prevention in CPI, Butterworths, London, 1996.
  • E G Frankel
E.G. Frankel, System reliability and risk analysis, Kluwer Academic, Dordrecht, The Netherlands, 1998.
Safe maintenance practice
  • F I Khan
  • S A Abbasi
F.I. Khan and S.A. Abbasi, Safe maintenance practice, Chem Ind Digest March (1998a), 91-105.
Risk assessment in chemical process industries: Advanced techniques
  • F I Khan
  • S A Abbasi
F.I. Khan and S.A. Abbasi, Risk assessment in chemical process industries: Advanced techniques, Discovery Publishing House, New Delhi, India, 1998b.
Offshore reliability data handbook
Orissa Renewable Energy Development Agency (OREDA), Offshore reliability data handbook, 3rd ed., DNV Veritasveien 1, N-1322 Hovik, Norway, 1997.