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International Journal of Engineering & Technology IJET-IJENS Vol: 12 No: 03 38 The differentiation and decision matrix risk assessment of accident precursors and near-misses on construction sites Qiang Chen, Weiwei Wu, and Xing Zhang Abstract—Precursors and near misses are well known for providing a major source of useful information for safety risk management. They are more frequent events than accidents and their causes may potentially result in an accident under slightly different circumstances. Despite the importance of this type of feedback, there is little knowledge on the characteristics of precursors and near misses, and on the use of this information in safety risk management....

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International Journal of Engineering & Technology IJET-IJENS Vol: 12 No: 03 38 The differentiation and decision matrix risk assessment of accident precursors and near-misses on construction sites Qiang Chen, Weiwei Wu, and Xing Zhang Abstract—Precursors and near misses are well of the precursors and near misses will give the potential known for providing a major source of useful to control variability rather than by constraining it. information for safety risk management. They are more Moreover, the investigation of precursors and near frequent events than accidents and their causes may misses incidents can be used as a source of information potentially result in an accident under slightly different for the construction of a structured methodological circumstances. Despite the importance of this type of approach for decision-making. Information from feedback, there is little knowledge on the characteristics precursors and near misses incidents investigations can of precursors and near misses, and on the use of this also be important tools for improved risk information in safety risk management. This paper communication. Index Terms— Precursors, Near misses, Risk-based focuses on differentiating the concepts of precursors related and evaluating the risk of precursors, near evaluation, Decision matrix. misses. First, precursors, near misses related concepts I. Introduction are reviewed and the relationships between the concepts are presented. Furthermore, the importance of Almost every year there is at least one precursors and near misses to further improve safety technological disaster that highlights the challenge margins are emphasized. Eventually, risk-based of managing technological risk. On February 1, evaluation of precursors, near misses is performed and 2003, the space shuttle Columbia and her crew the impacts of precursors, near misses on quantitative were lost during reentry into the atmosphere. In the risk estimates are emphasized. By describing the summer of 2003, there was a blackout that left precursors, near misses incidents with related millions of people in the northeast United States probabilities and consequences, proactive management without electricity. On March 23, 2005, the can be mobilized. Furthermore, a deeper understanding explosions and fires at BP’s Texas City refinery that killed 15 people and injured 170 [1]. Why Manuscript is received May 8, 2012. This work is based were the events that led to the accident not on three relative research projects respectively funded by recognized as harbingers? Why were risk reducing the National Natural Science Foundation of China (Grant steps not taken? No. 51008073), the Natural Science Foundation of Jiangsu A recent study by the US National Academy of Province (Grant No. BK2011609) and the Transportation Sciences, which brought together experts on risk, Science Research Project of Jiangsu Province (Grant No. engineers, practitioners, and policy makers from 2011Y14-2). different industries, focused on the signals, Qiang Chen is with the Institute of Construction and conditions, events and sequences that preceded and Real Estate, Southeast University, Nanjing 210096, PRC led up to accidents, and stated that many (e-mail: chenqiangjx@foxmail.com). organizations had attempted to develop programs Weiwei Wu is also with the Institute of Construction and to identify and benefit from accident precursors [2]. Real Estate, Southeast University, Nanjing 210096, PRC In this book, the author described the precursors (e-mail: wuweiwei@seu.edu.cn). strategies in aviation, the chemical industry, health Xing Zhang is also with the Institute of Construction and care, nuclear power and security operations. In Real Estate, Southeast University, Nanjing 210096, PRC addition to current practices, they also address (e-mail: zhx@seu.edu.cn). some areas for future research. 124303-7474 IJET-IJENS @ June 2012 IJENS IJENS
International Journal of Engineering & Technology IJET-IJENS Vol: 12 No: 03 39 Using accident precursors to predict and prevent industries, including the chemical and process, accidents is not a new idea. In the nuclear industry, airline, rail, nuclear, and medical disciplines [10]. the U.S. Nuclear Regulatory Commission (NRC) A compilation of papers with a cross industry started the Accident Precursors Sequence Program perspective is provided in Near misses Reporting in 1979 [3]. Over 1,000 licensee event reports are as a Safety Tool [14]. The most detailed study of submitted to the nuclear power plant (NPP) near misses management in the chemical industry regulator, the NRC, each year. The Aviation Safety known to us is the thesis of Van der Schaaf [15]. Reporting System operated by the National Jones et al. provide an account of near misses Aeronautics and Space Administration, have been management systems successfully applied in the in existence for several decades. The offshore European chemical industries [16]. petroleum industry in Norway has also reported Some studies have investigated how data from major hazard precursors to the authorities for a near misses should be used in safety management. decade [4]. Renewed interest in precursors analysis However, each study tends to emphasize one of the has shown that the evaluation of near misses is an following steps: identifying near misses, analyzing interdisciplinary effort, fundamental within the life data and defining actions resulting from the of an organization for reducing operational risks investigation of the events [17]. For example, and enabling accident prevention [5]. There has Brazier, Reason, Van Der Schaaf and Kanse, been notable work in the codifying and evaluation Renshaw and Wiggins, Dekker focused on the of precursors data through utilization of Bayesian stage of identifying these events [13], [18][21]. analysis [6][10]. Pate-Cornell presents a Bier and Mosleh addressed the analysis of near probabilistic approach to use precursors analysis to misses [7]. The study by Van Der Schaaf, create “signals that action has to be taken ... to undertaken in the context of the chemical industry, reduce the risks of failure as much as possible proposed a set of steps for the use of data from within resource constraints [11].” Carroll near misses [22]. demonstrates the importance of knowledge This research focuses on differentiating the management within organizations, so that concepts of precursors related and evaluating the precursors can be effectively addressed as “signals risk of precursors, near misses. The first part of the of possible problems” and “opportunities to enact paper briefly reviews some of the previous studies. and improve organizational practices [12].” The remainder of the article is organized as Phimister et al. not only observe the follows. In Section 2, the definitions of concepts interdisciplinary nature of precursors analysis but precursors related are presented. Section 3, also the fact that this practice is diffused across differentiate the concepts precursors related. different industries [2]. Section 4, describes the importance of precursors Near misses are well known for providing a and near misses to further improve safety margins. major source of useful information for safety Section 5, risk-based evaluation of precursors and management. The use of data from near misses in near misses is proposed. Section 6, emphasized the safety management has been identified as an impact of precursors and near misses on important practice in the prevention of accidents, quantitative risk estimates. Section 7, provides especially in the areas of civil aviation, the conclusions. generation of nuclear power, the chemical industry II. Review of precursors and near misses related and, more recently, in railroad transport and concepts medicine [13]. Near misses management systems have been A. Precursors developed and are implemented across a range of Recognizing signals before an accident occurs 124303-7474 IJET-IJENS @ June 2012 IJENS IJENS
International Journal of Engineering & Technology IJET-IJENS Vol: 12 No: 03 40 offers the potential for improving safety, Many refer to as “small histories”—or fragments of what organizations had sought to develop programs to might be experienced if an accident occurred [26]. identify and benefit from accident precursors, A To benefit from near misses, organizations ranging recent study by the US National Academy of from hospitals to manufacturing facilities and Sciences focused on these precursors which were airlines to power plants, have set up management defined as the conditions, events and sequences systems for reporting and analyzing near misses that preceded and led up to accidents or the [7], [15], [16], [27]. ‘building blocks’ of accidents [2]. The National It has been widely accepted that accidents are Academy of Engineering workshop definition of just the tip of an iceberg. Near accidents, events in an accident precursor is any event or group of which no damages or injuries occur but, under events that must occur for an accident to occur in a slightly different circumstances, could have given scenario, Based on this definition a precursor resulted in harm, are important sources of is identified in a much wider range of severities information about accident precursors [28], [29]. and may include all defects and abnormal events. Near misses accidents were usually referred to as Similarly, Suraji et al. explained this concept as an precursors of accidents [7], indicators of potential undesired event, which was an unwanted incident accidents when luck runs out [30] or imminent immediately preceding and leading to an accident signals of accidents [16]. Ritwik adopted a very that did, or could have caused injury to simple definition of near misses as an incident or construction personnel or the general public, or unsafe condition with potential for injury or damage to property or the environment [23]. property damage [31]. Phimister et al. defined near Skogdalen and Vinnem described a precursor misses as an opportunity to improve environmental, incident is an event or group of events that health and safety practice based on a condition, or indicates failure in systems controlling the risks an incident with potential for more serious from a major hazard [24]. When adopting a broad consequence [10]. Phimister et al. identified a near definition of precursors, it is not difficult to find miss accident as a special kind of precursors and it that a near miss accident is an important kind of was defined as an event in which no damages or precursors [2], [19]. However, some organizations injuries actually occurred but, under slightly such as the U.S. NRC, have chosen to limit the use different circumstances, could have resulted in of the term ‘precursors’ to events that exceed a harm [2]. In construction, the modified statistical specified level of severity. For example, precursors triangle of accident causation described the same might be defined as the complete failure of one or process from near miss accidents to fatal accidents more safety systems and/or the partial failure of [32]. Cambraia et al. adopted the concept of a near two or more safety systems [2]. Likewise, Wu et al. miss accident as an instantaneous event that adopted the concept of precursors to the events that involved the sudden release of energy and had the exceed a specified level of severity [25]. potential to generate an accident [17]. Its consequences do not result in personal injuries or B. Near misses material damage, but usually only in the loss of To organizations seeking to learn about time. This concept also implies that a near miss has potential accidents, near misses represent the potential to result in accidents with exclusively inexpensive learning opportunities for analyzing material damages. Rathnayaka et al. describes the what can go wrong. Near misses are especially term ‘near miss’ as an event that does not result in important for organizations that have not an actual loss but that has the potential to do so experienced a major accident, because they enable [33]. these organizations to experience what March et al. 124303-7474 IJET-IJENS @ June 2012 IJENS IJENS
International Journal of Engineering & Technology IJET-IJENS Vol: 12 No: 03 41 business operation, the concept do not refer to C. Immediate factor actual injury to a person [38]. Rathnayaka et al. Undoubtedly, immediate factors are important described an incident is an event that could cause exacerbating factors of accidents. An updated considerable harm or loss [33]. domino sequence led to the comprehension of immediate causes before an accident [34]. Jones et E. Accident al. defined the direct causes as immediate reason Heinrich et al. considered an accident is why an incident occurred, usually consisting of unplanned and uncontrolled event in which the unsafe conditions at the site or unsafe acts by a action or reaction of an object, substance, person, person [16]. Chua et al. described the immediate or radiation results in personal injury or the causes are the triggers that directly lead to the probability thereof [38], Based on this definition incident sequence, Further he classified the accidents could encompass the idea of no injury immediate causes into substandard/unsafe accidents as well as injury accidents. Bentil conditions and substandard/unsafe acts, which described accident as an unplanned act, event or refer to the respective physical conditions and occurrence, within a sequence of events, which can human behaviors that do not meet safety cause unintended personal injury or death, property requirements and can directly cause incident damage or both [39]. Perrow defined an accident occurrences [35]. Fang et al. found that immediate as a failure in a subsystem, or the system as a factors were caused by unsafe conditions and whole, that damages more than one unit and in unsafe actions [36]. The Loughborough’s ConCA doing so disrupts the ongoing or future output of accident causality model recognized that the system [40]. Qureshi described an accident as immediate accident circumstances were failures in an event that occurs from inappropriate or the interaction between the work team, workplace, inadequate control or enforcement of safety-related equipment and materials. Wu et al. adopted the constraints on the development, design, and same concept in their research [25]. operation of the system, rather than simply occurring due to independent component failures D. Incident [41]. Rathnayaka et al. identified an accident as an It is common to use the term near miss as a event that may cause fatalities, damage to property synonym of incident [19], [37]. However, some and impact to the environment [33]. authors consider that incidents include accidents, Simultaneously, accidents were classified near misses, unsafe acts and conditions [13], [16], according to the degree of severity by some [18]. Similarly, Jones et al. defined incidents as all research [16], [32], [33]. undesired events, including accidents and near misses [16]. Phimister et al. defined incidents as all F. Harzard safety related events, including accidents (with We are surrounded by hazards all our lives. negative outcomes, such as damage and injury), Most of them we accept without concern [42]. near misses (situations in which accidents could Bentil defined hazard is a condition, act or event have happened if there had been no timely and that has the potential of causing an accident or effective recovery), and dangerous situations [2]. illness [39]. A hazard is “an inherent physical or Cambraia et al. described incidents as an umbrella chemical characteristic that has the potential for term adopted to refer to any situation in which causing harm to people, the environment, or there is a lack of safety. There are different points property” [43]. The Health and Safety Commission of view in some research [17]. Heinrich et al. defined hazard as the potential to cause harm [44]. defined an incident as an undesired event that Hazard has also been defined as an inherent could (or does) downgrade the efficiency of the 124303-7474 IJET-IJENS @ June 2012 IJENS IJENS
International Journal of Engineering & Technology IJET-IJENS Vol: 12 No: 03 42 characteristic of a thing or situation that has the accident is preceded by numerous incidents and potential of causing an unplanned or undesired near misses in his famous iceberg metaphor [51]. event or series of events that have harmful Similarly, Investigation of major accidents shows consequences, such as injury, death, environmental that for every serious accident, a larger number of harm, or illness [45]. incidents result in limited impact and an even larger number of incidents result in no loss or F Safety barrier damage [10]. Several authors mention the The term safety barrier and similar terms like existence of precursors being present in the defence (in-depth), layer of protection, safety organization before an accident occurs. For (critical) function, safety critical element, and example, Lees and Tweeddale mention only safety system are applied in regulations, standards, technical precursors [52], [53], whilst Reason, and the scientific literature [46]. No common Turner, and Perrow indicate the presence of definition of the term safety barrier has been found organizational precursors [19], [54], [55]. Various in the literature, although different aspects of the accident triangles show that for each major term have been discussed and applied in practice accident there are a large number of minor for several decades. Safety barriers are categorized accidents and even more near misses [10], [32], in numerous ways by different authors and the [53]. performance of the barriers is described in several It has been demonstrated in various studies, e.g. (Bird and Germain, 1966; Tye, 1976；Heinrich, ways. In the Oxford English Dictionary a barrier is 1980) that there is a relationship between the defined as a ‘‘fence of material obstruction of any numbers of near misses, minor incidents and major kind erected (or serving) to bar the advance of accidents [38], [56], [57]. In order to effectively persons or things, or to prevent access to a place’’ discuss, Phimister et al. defined precursors are [47]. The concept of defence-in-depth constitutes sequences or events in the accident chain, the basis for the discussion of safety barriers. accidents have been preceded by events, behaviors, IAEA describes the term safety barrier is often and conditions that were ingredients of the recipe used in a broader meaning as a collective term for for the adverse consequences [2]. On some different means used to realize the concept of occasions a precursor event can be considered defence in depth [48]. A safety barrier is related to synonymous with a near miss. Precursors are a hazard, an energy source or an event sequence. signals of possible problems, chinks in an This is supported by the requirement stated by operation’s armor, or pathways to accidents. They PSA [49]. This means that a barrier should be well are called precursors rather than accidents because defined or formalised and be related to a specific systems have multiple layers of defense like slices hazard. Sklet suggests the definition of safety of Swiss cheese stacked together [19]. A precursor barriers are physical and/or nonphysical means problem may pass through one or two layers of planned to prevent, control, or mitigate undesired defense (through the holes in the Swiss cheese), events or accidents [46]. but another layer usually stops the progression toward an accident. Only when “all of the holes III. Relationships between the aforementioned line up” does the problem overcome or bypass all concepts and differentiate the relevant concepts defenses and become an accident. In spite of all kinds of safety measures and It should be pointed out that when adopting a indicators used, major catastrophes still occur [50]. broad definition of precursors, it is not difficult to Were there no signs indicating that an accident was find that near miss is an important kind of on its way? Heinrich already stated that an precursor [2], [16]. However, some organizations, 124303-7474 IJET-IJENS @ June 2012 IJENS IJENS
International Journal of Engineering & Technology IJET-IJENS Vol: 12 No: 03 43 such as the U.S. NRC, have chosen to limit the use between the terms near misses, unsafe acts and of the term precursors to near misses that exceed a conditions. Cambraia et al. considered that the specified level of severity [2]. Likewise Wu et al. difference between these events is in the time of the adopted the same concept. Although near misses action and in whether or not there has been a sudden are clearly related to precursors [25], Phimister et release of energy [17]. While in unsafe acts and al. have tried to distinguish near misses from conditions, the situation of risk arises from a precursors, and encourage not to use them continuous action or is latent in the environment interchangeably [2]. They define a near miss is as (for example, an employee working high up who an almost complete progression of events—a does not use a safety belt), in near misses there is an progression that, if one other event had occurred, instantaneous action, which involves the sudden would have resulted in an accident. A near miss release of energy. might consist of one or more precursors that did Immediate factors are important exacerbating occur, and one that did not. Based on this factors of accidents on construction sites. An definition, a near miss can be considered a updated domino sequence led to the particularly severe precursor. For instance, when comprehension of immediate cause before an the necessary exacerbating factors are highly likely, accident [34]. Differences between precursors and the precursor is called a near miss. Similarly, one immediate factors lie in the difficulty for would expect a precursor to be called a near miss if performing preventive actions due to time the mitigating factors were unlikely or not robust. constraint. Immediate factors always have tight Likewise Meel and Seider described the near period allowed for taking actions [25]. misses and incidents are also called accident In this study, the general definition of precursors, precursors as their occurrences portend an near misses, immediate factors, incident, accident, increasing likelihood of accidents, near misses have hazard and safety barriers have been used [2], [16], less potential for adverse scenarios compared with [45], [46]: incidents, but when recognized, they signal the The precursors are defined as sequences or likelihood of future incidents and accidents, often in events in the accident chain, a precursor problem time to take preventive action [58]. By reviewing may pass through one or two layers of defense previous research, the relationship between the (through the holes in the Swiss cheese), but numbers of precursors, near misses, minor another layer usually stops the progression toward incidents and major accidents could be described an accident. A near miss is defined as an almost by the well known Safety Pyramid [56] shown in complete progression of events—a progression that, Fig. 1. if one other event had occurred, would have resulted in an accident. Immediate factors are defined as immediate causes before an accident. Incidents are defined as all safety related events, including accidents, near misses and precursors. A accident is defined as an complete progression of events (all of the holes in the Swiss cheese line up). A hazard is defined as an inherent characteristic of a thing or situation that has the potential of causing an unplanned or undesired event or series of events that have harmful consequences, such as injury, Fig. 1. Safety pyramid (the lowest strata, precursors, is not death, environmental harm, or illness (holes in the shown by Bird and Germain, 1966) It is also common for no distinction to be made Swiss cheese). Safety barriers are defined as 124303-7474 IJET-IJENS @ June 2012 IJENS IJENS
International Journal of Engineering & Technology IJET-IJENS Vol: 12 No: 03 44 physical and/or non-physical means planned to prevent, control, or mitigate undesired events or accidents. According to the above definitions, the presented paper described the relationships of the above concepts by a causal sequence diagram (Fig. 2). Based on the Safety pyramid (Fig.1) and the causal sequence diagram (Fig.2), this paper differentiate the precursors, near misses and accidents from three aspects of proximity, incidents rates, potential consequence by a bubble chart (Fig.3). Fig.3. Bubble chart Fig. 2. Causal sequence diagram of the accident ‘‘building blocks’’ of accidents [2]. IV. The importance of precursors and near Grabowski et al. also echoed that recognizing misses to further improve safety margins alerts and signals before an accident clearly A primary purpose in measuring safety is to offers the potential of improving safety [59]. develop intervention strategies to avoid future In the aftermath of catastrophes, it is accidents [59]. Recognizing signals before an common to find prior indicators, missed accident occurs offers the potential for signals, and dismissed alerts that, had they improving safety, and many organizations been recognized and appropriately managed have sought to develop programs to identify before the event, might have averted the and benefit from alerts, signals and prior undesired event [2]. To prevent major, though indicators. A recent study by the US National infrequent, event occurrence, it is important to Academy of Sciences focused on these signals, consider accident precursors (symptoms of the conditions, events and sequences that hazards) such as operational deviations, precede and lead up to accidents, or the 124303-7474 IJET-IJENS @ June 2012 IJENS IJENS
International Journal of Engineering & Technology IJET-IJENS Vol: 12 No: 03 45 mishaps, and near misses, in order to prevent Commission (NRC) for almost twenty years events at source rather than controlling or [24]. For a given accident scenario, near mitigating them [33]. One of the most misses can and frequently do occur with attractive aspects of precursors analysis is the greater frequency than the actual event [56]. abundance of precursors events compared to Similarly, the “Iceberg concept” about the actual accidents [56]. Analyzing precursors proportionality between different categories of data can therefore reduce the uncertainty accidents and near misses also says that the about the likelihood of an accident and lead to more near misses (or other deviations) you better decisions. The relatively high frequency have the more frequently you will have and low cost associated with precursor events accidents. suggest that many industries could benefit To organizations seeking to learn about from using precursors analyses to reduce the potential accidents, near misses represent risk of accidents. inexpensive learning opportunities for Programs for managing accident precursors analyzing what can go wrong. Near misses are have a number of benefits, as outlined by van especially important for organizations that der Schaaf et al. [14]. First, reviewing and have not experienced a major accident, analyzing observed precursors can reveal what because they enable these organizations to can go wrong with a particular system or experience what March et al. refer to as “small technology and how accidents can develop histories”—or fragments of what might be experienced if an accident occurred [26]. To (modeling). Second, because precursors generally occur much more often than benefit from near misses, organizations accidents, analyses of accident precursors can ranging from hospitals to manufacturing help in trending the safety of a system facilities and airlines to power plants, have set (monitoring). Finally, and perhaps most up management systems for reporting and important, precursors programs can improve analyzing near misses [7], [15], [16], [27]. organizational awareness (mindfulness) of As near misses are much more frequent safety problems [60]. The investigation of events that accidents, they may indicate, in a precursor events can be used as a source of proactive way, critical areas for improvement information for the construction of a in safety management [16], [19], [22], [37]. In structured methodological approach for addition, using near misses helps to strengthen operational decisions [61]. Skogdalen and the safety culture [16], [62], [63], especially Vinnem thought that information from when workers are motivated to participate in precursor incidents investigations can also be the process of identification and analysis of important tools for improved risk those events [16], [19]. Indeed, studies in the communication [24]. construction and chemical industries have One way organizations seek to benefit from indicated that accident rates tend to diminish precursors is by analyzing near misses in keeping with the rate at which the number (sometimes referred to as near accidents, near of near misses identified increases [16], [64]. hits, or close calls), fragments of an accident So if we report near misses, and learn from scenario that can be observed in them, we will eventually get to the point isolation—without the occurrence of an where near misses occurrence itself reduces. A accident [10]. Precursors analysis, the reduction in the numbers of near misses which evaluation of “near misses,” has been an proceed to full-blown accidents follows. activity of the U.S. Nuclear Regulatory 124303-7474 IJET-IJENS @ June 2012 IJENS IJENS
International Journal of Engineering & Technology IJET-IJENS Vol: 12 No: 03 46 V. Risk-based evaluation Table I Data for relevance index In this passage, a decision matrix risk Relevance index assessment technique is presented, which has Criteria Weighting been based on and produced with the help of 1.Proximity index the works of Johnson, Woodruff, Reniers et al., How far away was the incident from becoming a accident? Marhavilas and Koulouriotis [65][68]. One step away 3 The combination of a relevance index and Two steps away 2 consequence potential factor range, gives us More than two steps away 1 an estimate of risk (or a risk ranking). The Remote 0 relevance index is composed of proximity 2.Visibility index index (1), visibility index (2) and Probability Is the incident visible before it lead to the accident? index (3). The consequence potential factor is With great difficulty 3 composed of casualties (a), property Loss (b), Some insight 2 environmental releases/exceeding standards (c) Obvious 1 and evacuation (d). Widely know 0 Furthermore, the product of the relevance 3. Probability index index and consequence potential factor Occurrence rate of the incident in daily operation. provides a measure of risk which is expressed High probability 3 by the relation: Medium probability 2 Relevance index=1+2+3 Low probability 1 Consequence potential factor=a×b×c×d Not expected to happen 0 In order to reduce the subjectivity of the Relevance index (1+2+3) 0 to 9 evaluation, criteria were established to classify precursors or near misses according to their Table II degree of severity (level of impact if the Data for consequence potential factor accident had happened), proximity (how far Consequence potential factor Weighting away was the incident from becoming a a) Casualties accident),visibility (is the incident visible Death 3 before it lead to the accident) and probability Serious injury 2 (estimate of the likelihood of an accident Injury 1 occurring if no preventive action additional to b) Property Loss those already in place is taken), as shown in $500,000 or more 3 Tables Ⅰ and Ⅱ Criteria and their weightings . $50,000-500,000 2 could be customized to suit local needs. $0-50,000 1 Once the precursors or near misses has c) Environmental releases/ Exceeding standards been identified, the question of assigning 8 hours or 100% 3 relevance index and consequence potential 1 hour or 10% 2 factor must be addressed, like in Tables 1 and 30 minutes or 5% 1 2. It is very important to note that frequency d) Evacuation estimations and consequence estimations are More than 100 individuals 3 very well considered and performed by 50-100 individuals 2 experienced risk managers [67]. Less than 50 individuals 1 Eventually, the technique is consummated Consequence potential factor (a×b×c×d) 0 to 81 by the construction of the risk matrix (in Fig. 124303-7474 IJET-IJENS @ June 2012 IJENS IJENS
International Journal of Engineering & Technology IJET-IJENS Vol: 12 No: 03 47 4), which have been developed by the or near miss will be the basis to classify the combination of Tables and and the usage incident in one out of three zones of risk (Fig. of the above relation. 4): red (incidents with the highest risk), The developed decision matrix risk yellow (incidents with medium risk) and green assessment technique has two key advantages: (incidents with the lowest risk). The red zone a) It differentiates relative risks to facilitate means that not enough barriers have been decision making. b) It improves the implemented and risk cannot be tolerated. The consistency and basis of decision. Moreover, it yellow and green zones finally state that is a quantitative (due to risk measuring) and enough layers of protection are present in also a graphical method which can create order not to select the scenario. The liability issues and help the risk managers to classification in zones is necessary since the prioritize and manage key risks. choice was made not to assign weights to rank The relevance index and consequence each category of relevance index and severity. potential factor associated with each precursor Fig. 4. Risk matrix of precursors and near misses precursors [9]. VI. Impacts on quantitative risk estimates Since precursors (near misses) consist of In estimating the frequency of rare events, event sequences rather than individual the number of observed events (typically component failures, precursors data will either 0 or 1) will generally be too small to automatically reflect the effects of any support the development of accurate estimates dependencies that may exist between by means of the usual statistical estimator, components or systems that were challenged Two alternative approaches have been during the observed precursors [6]. The suggested to overcome this problem: (1) analysis of precursors data has therefore probabilistic risk analysis (PRA), in which the attracted considerable attention as an approach accident frequency is estimated as a function for estimating the frequencies of severe of the failure rates of individual components; accidents. As it is well known, the occurrence rate Φ and (2) the use of data on accident “precursors” or “near misses” [6]. Kirchsteiger thought that of an accident of a certain type with the significance of quantitative risk estimates consequences equalling or exceeding a certain depends not only on the number of accident magnitude can be quantified as a events included, but also on the criteria maximum-likelihood estimate across the given differentiating accidents and accident observation time T, 124303-7474 IJET-IJENS @ June 2012 IJENS IJENS
International Journal of Engineering & Technology IJET-IJENS Vol: 12 No: 03 48 specific accident type under consideration) is . Ф|T= 。 often quite large compared to the number of accidents — “conventional” risk estimates of Taking into account precursors or near misses, the frequency of an accident can be the represented as the product of two quantities, . Ф|T= 。 Ф|T=∑ λkφk where, Ф| T = frequency of a specific type are not very dependable. accident in observation time T (e.g. ﬁre in a VII. Conclusions plant with fatalities or injuries > 0), λk = frequency of precursors or near misses type k The concepts of precursors, near misses are (e.g. any ﬁre in the plant), φk = conditional presented and discussed in the paper. The frequency of the accident of interest, given a results are based on experience from several precursors or near misses of type k (e.g. fire research projects focusing on precursors, near with fatalities or injuries > 0, given any fire) misses and a review of relevant literature. No [16]. common terminology applicable crosswise Based on the above discussion, Jones et al. between sectors and application areas has been described near misses can thus be viewed to found, and a set of definitions is therefore yield either an increased or a decreased overall proposed in the paper. accident frequency by either increasing the Precursors are defined as sequences or near misses frequency or decreasing the events in the accident chain, a precursor conditional frequency of an accident given a problem may pass through one or two layers near misses, depending on the prior of defense (through the holes in the Swiss distributions for both the near misses cheese), but another layer usually stops the frequency and the conditional accident progression toward an accident. While near frequency [16]. miss is defined as an almost complete The question of interest is thus whether the progression of events—a progression that, if inclusion of observations of precursor and near one other event had occurred, would have miss events which do not end up in accidents resulted in an accident. Accident is defined as can actually result in significantly different a complete progression of events (all of the (increased or decreased) accident frequencies holes in the Swiss cheese line up). So defined and thus overall risk estimates. As analytically in order to facilitate the distinction between shown in Kirchsteiger [9], the inclusion of near precursors, near misses and accidents. misses events not resulting in an accident has It has been demonstrated in various studies, e.g. (Bird and Germain, 1966; Tye, 1976 ； the potential to significantly increase the values of corresponding risk estimates. In other Heinrich, 1980) [38], [56], [57] that there is a words, not considering precursors and near relationship between the numbers of precursors, misses occurrences can result in significant near misses, minor incidents and major under estimation of the “true” risk. accidents. Investigation of major accidents Thus, if the statistical basis for quantitative shows that for every serious accident, a larger risk estimates consists only of “top events” (e.g. number of near misses and an even larger accidents of a certain type) instead of explicitly number of precursors. In this paper, the author covering both accidents and accident described the relationship between precursors, precursors, there is the danger that—since the near misses and accidents by a Safety pyramid, number of near misses (i.e. of precursors to the Causal sequence diagram of the accident and a 124303-7474 IJET-IJENS @ June 2012 IJENS IJENS
International Journal of Engineering & Technology IJET-IJENS Vol: 12 No: 03 49 Bubble chart. ACKNOWLEDGMENT The importance of precursors and near The authors would like to express sincere misses to further improve safety margins has thanks to Institute of Construction and Real been emphasized. Analyzing precursors data Estate, Southeast University for endless can therefore reduce the uncertainty about the support throughout this project. likelihood of an accident and lead to better decisions. The relatively high frequency and References low cost associated with precursors events [1] M. Kalantarnia, F. Khan and K. Hawboldt. suggest that many industries could benefit Dynamic risk assessment using failure from using precursors analyses to reduce the assessment and Bayesian theory, Journal risk of accidents. of Loss Prevention in the Process To organizations seeking to learn about Industries, vol. 22, 2009, pp. 600–606. potential accidents, near misses represent [2] J. R. Phimister, V. M. Bier and H. C. inexpensive learning opportunities for Kunreuther(Eds). Accident Precursors analyzing what can go wrong. Near misses are Analysis and Management: Reducing especially important for organizations that Technological Risk through Diligence, have not experienced a major accident, National Academy Press, Washington, DC, because they enable these organizations to 2004. experience what March et al. [26] refer to as [3] M. B. Sattison. Nuclear accident “small histories”—or fragments of what might precursors assessment: The accident be experienced if an accident occurred. sequence precursors program, In J. R. In this paper, a decision matrix risk Phimister, V. M. Bier and H. C. assessment technique is presented. The Kunreuter(Eds). Accident Precursors combination of a relevance index and Analysis and Management: Reducing consequence potential factor range, gives us Technological Risk through Diligence (pp. an estimate of risk (or a risk ranking). The 89–100). National Academic Press, developed decision matrix risk assessment Washington, DC, 2004. technique is a quantitative (due to risk [4] J. E. Vinnem, J. A. Hestad and J. T. measuring) and also a graphical method which Kvaløy. Analysis of root causes of major can create liability issues and help the risk hazard precursors (hydrocarbon leaks) in managers to prioritize and manage key risks. the Norwegian offshore petroleum The impact of precursors and near misses on industry, Reliability Engineering and quantitative risk estimates has also been System Safety, vol. 95, 2010, pp. emphasized. If the statistical basis for 1142–1153. quantitative risk estimates consists only of “top [5] C. L. Smith and E. Borgonovo. Decision events” (e.g. accidents of a certain type) Making During Nuclear Power Plant instead of explicitly covering both accidents Incidents—A New Approach to the and accident precursors, there is the danger Evaluation of Precursors Events, Risk that—since the number of near misses (i.e. of Analysis, vol. 27, 2007, pp. 1027–1042. precursors to the specific accident type under [6] V. M. Bier and W. Yi. The performance of consideration) is often quite large compared to precursors-based estimators for rare event the number of accidents—“conventional” risk frequencies, Reliability Engineering and estimates are not very dependable. System Safety, vol. 50, 1995, pp. 241–251. 124303-7474 IJET-IJENS @ June 2012 IJENS IJENS
International Journal of Engineering & Technology IJET-IJENS Vol: 12 No: 03 50 [7] V. M. Bier, and A. Mosleh. The analysis tool, Oxford: Butterworth-Heinmann, of accident precursors and near misses: 1991. Implications for risk assessment and risk [15] T. W. Van Der Schaaf. Near misses management, Reliability Engineering and Reporting in the Chemical Process System Safety, vol. 27, 1990, pp. 91–101. Industry, Eindhoven University of [8] S. Kaplan. On the inclusion of precursors Technology, the Netherlands, 1992. and near misses events in quantitative risk [16] S. Jones, C. Kirchsteiger and W. Bjerke. assessments: A Bayesian point of view The importance of near misses reporting to and a space shuttle example, Reliability further improve safety performance, Engineering and System Safety, vol. 27, Journal of Loss Prevention in the Process 1990, pp. 103–115. Industries, vol. 12, 1999, pp. 59–67. [9] C. Kirchsteiger. Impact of accident [17] F. B. Cambraia, T. A. Saurin and C. T. precursors on risk estimates from accident Formoso. Identification, analysis and databases, Journal of Loss Prevention in dissemination of information on near the Process Industries, vol. 10, 1996, pp. misses: A case study in the construction 159–167. industry, Safety Science, vol. 48, 2010, pp. [10] J. R. Phimister, U. Oktem, Kleindorfer P 91–99. R, et al. Near-Miss Incident Management [18] A. J. Brazier. A summary of incident in the Chemical Process Industry, Risk reporting in the process industry, Journal Analysis, vol. 23, 2003, pp. 445–459. of Loss Prevention in the Process [11] E. Paté-Cornell. On signal, response and Industries, vol. 7, 1994, pp. 243–248. risk mitigation: A probabilistic approach [19] J. Reason. Managing the Risks of to the detection and analysis of precursors, Organizational Accidents, Ashgate, In J. R. Phimister, V. M. Bier and H. C. Burlington, 1997. Kunreuter(Eds). Accident Precursors [20] P. F. Renshaw and M. W. Wiggins. A Analysis and Management: Reducing self-report critical incident assessment tool Technological Risk through Diligence (pp. for army night vision goggle helicopter 49–59). National Academic Press, operations, Human Factors, vol. 49, 2007, Washington, DC, 2004. pp. 200–213. [12] J. S. Carroll. Knowledge management in [21] S. Dekker. Just Culture: Balancing Safety high hazard industries, In J. R. Phimister, and Accountability. Ashgate, London, V. M. Bier and H. C. Kunreuter(Eds). 2007. Accident Precursors Analysis and [22] T. W. Van Der Schaaf. Near misses Management: Reducing Technological reporting in the chemical process industry: Risk through Diligence (pp. 127–136), an overview, Microelectronics and National Academic Press, Washington, Reliability, vol. 35, 1995, pp. 1233–1243. DC, 2004. [23] A. Suraji, A. R. Duff and S. J. Peckitt. [13] T. W. Van Der Schaaf and L. Kanse. Development of causal model of Biases in incident reporting databases: an construction accident causation, Journal of empirical study in the chemical process Construction Engineering and industry, Safety Science, vol. 42, 2004, pp. Management, vol. 127, 2001, pp. 337–344. 57–67. [24] J. E. Skogdalen and J. E. Vinnem. [14] T. W. Van der Schaaf, D. A. Lucas and A. Quantitative risk analysis R. Hale. Near-miss reporting as a safety offshore—Human and organizational 124303-7474 IJET-IJENS @ June 2012 IJENS IJENS
International Journal of Engineering & Technology IJET-IJENS Vol: 12 No: 03 51 factors, Reliability Engineering and [34] F. Bird. Management Guide to Loss System Safety, vol. 96, 2011, pp. Control, Institute Press, Atlanta, 1974. 468–479. [35] D. K. H. Chua. M. ASCE and Y. M. Goh. [25] W. Wu, H. Yang, D. A. S. Chew, S. Yang Incident Causation Model for Improving and Q. M. Li. Towards an autonomous Feedback of Safety Knowledge. Journal of real-time tracking system of near misses Construction Engineering and accidents on construction sites, Management, vol. 130, 2004, pp. 542–551. Automation in Construction, vol. 19, 2010, [35] D. P. Fang. Y. Chen and L. Wong. Safety pp. 134–141. climate in construction industry: a case [26] J. G. March, L. S. Sproull and M. Tamuz. study in Hong Kong, Journal of Learning from samples of one or fewer, Construction Engineering and Organization Science, vol. 2. 1991, pp. Management, vol. 132, 2006, pp. 573–584. 1–13. [36] A. Gibb. R. Haslam, D. Gyi, et al. What [27] P. Barach, and S. D. Small. Reporting causes accidents? Proceedings of the and preventing medical mishaps: lessons institution of civil engineers, Civil from non-medical near misses reporting engineering, vol. 159. 2006, pp. 46–50. systems, British Medical Journal, vol. 320, [37] J. Hinze. Construction Safety. 2000, pp. 759–763. Prentice-Hall, Upper Saddle River, NJ, [28] NRC (National Research Council). 1997. Improving Aircraft Safety: FAA [38] H. W. Heinrich, D. Petersen and N. Roos. Certification of Commercial Passenger Industrial Accident Prevention: A Safety Aircraft, Washington, D.C.: National Management Approach, McGraw-Hill, Inc, Academy of Sciences, 1980. New York, 1980. [29] M. Tamuz. The impact of computer [39] K. K. Bentil. A Model for Predicting surveillance on air safety reporting, Commercial Construction Site Accidents, Columbia Journal of World Business, vol. University of Florida, 1990. 22, 1987, pp. 69–77. [40] C. Perrow. Normal Accidents. Princeton, [30] A. J. Brazier. A summary of incident N.J.: Princeton University Press, 1999. reporting in the process industry, Journal [41] Z. H. Qureshi. A review of accident of Loss Prevention in the Process modeling approaches for complex Industries, vol. 1994, pp. 243–248. socio-technical systems, In: Proc. 12th [31] U. Ritwik. Risk-based approach to near Australian Conference on Safety-Related misses, Safety management, 2002. Programmable Systems, Adelaide, [32] G. Carter, and S. D. Smith. Safety hazard Australia, 2007. identiﬁcation on construction projects, [42] M. Tweeddale. Managing Risk And Journal of Construction Engineering and Reliability Of Process Plants , Copyright Management, vol. 132, 2006, pp. 197–205. © 2003 by Elsevier Science (USA). [33] S. Rathnayaka, F. Khan and P. Amyotte. [43] CCPS (Center for Chemical Process SHIPP methodology: Predictive accident Safety). Guidelines for Hazard Evaluation Procedures, 2nd ed, New York: American modeling approach. Part I: Methodology and model description, Process Safety and Institute of Chemical Engineers, 1992. Environmental Protection, vol. 89, 2011, [44] Health and Safety Commission. pp. 151–164. Designing for health and safety in construction, HSE Books, London, 1995. 124303-7474 IJET-IJENS @ June 2012 IJENS IJENS
International Journal of Engineering & Technology IJET-IJENS Vol: 12 No: 03 52 [45] L. D. Gowen, J. S Collofollo. Software [57] J. Tye. Accident Ratio Study. London: safety and preliminary hazard analysis. British Safety Council, 1976. Prof. Saf, 1994, pp. 20–25. [58] A. Meel and W. D. Seider. Plant-speciﬁc [46] S. Sklet. Safety barriers: Definition, dynamic failure assessment using classification, and performance. Journal of Bayesian theory. Chemical Engineering Loss Prevention in the Process Industries, Science, vol. 61, 2006, pp. 7036–7056. vol. 19, 2006. pp. 494–506. [59] M. Grabowski, P. Ayyalasomayajula, J. [47] OED. Oxford English dictionary online. Merrick, et al. Leading indicators of safety Oxford: Oxford University Press, 2005. in virtual organizations, Safety Science, [48] IAEA. Basic safety principles for nuclear vol. 45, 2007, pp. 1013–1043. power plants: 75-INSAG-3, rev.1. Vienna: [60] K. E. Weick and K. M. Sutcliffe. The International Atomic Energy Agency, Managing the Unexpected: Assuring High 1999. Performance in an Age of Complexity, [49] PSA. Regulations relating to management New York: John Wiley and Sons, 2001. in the petroleum activities (The [61] E. Borgonovo, C. Smith, G. Apostolakis, Management Regulations), Norway, et al. Insights from using influence Stavanger: Petroleum Safety Authority, diagrams to analyze precursor events, 2001. FRONTIERS SCIENCE SERIES. vol. 3, [50] P. J. M. Sonnemans and P. M. W. 2000, pp. 1801-1808. Korvers. Accidents in the chemical [62] M. D. Cooper. Towards a model of safety industry: are they foreseeable?, Journal of culture, Safety Science, vol. 36, 2000, pp. Loss Prevention in the Process Industries, 111–136. vol. 19, 2006, pp. 1–12. [63] A. I. Glendon, and N. A. Stanton. [51] H. W. Heinrich. Industrial accident Perspectives on safety culture, Safety prevention. McGraw-Hill New York, Science, vol. 34, 2000, pp. 193–214. 1931. [64] J. Hinze. Making Zero Injuries a Reality, [52] F. P. Lees. Hazard warning structure: A Report to the Construction Industry Some illustrative examples based on actual Institute, University of Florida, cases, Reliability engineering, vol. 10, Gainesville, Report 160, 2002. 1982, pp. 65–81. [65] W. G. Johnson. The management [53] H. M. Tweeddale. Principles and oversight and risk tree. Prepared for the practices for design of process safety U.S. Atomic Energy Commission, 1973. monitoring and auditing programmes, [66] J. M. Woodruff. Consequence and Loss prevention and safety promotion in likelihood in risk estimation: a matter of the process industries, vol. 1, 1995, pp. balance in UK health and safety risk 71–82. assessment practice, Safety Science, vol. [54] B. A. Turner. Man-made disasters. 43, 2005, pp. 345–353. London:Wykeham Publications Ltd, 1978. [67] G. L. L. Reniers, W. Dullaert, B. J. M. [55] C. Perrow. Normal accidents. New York: Ale, et al. Developing an external domino Basic Books, 1984. prevention framework: Hazwim, Journal [56] F. E. Bird and G. L. Germain. Practical of Loss Prevention in the Process loss control leadership. Loganville, GA: Industries, vol. 18, 2005, pp. 127–138. Det Norske Verita, 1966. [68] P. K. Marhavilas, D. E. Koulouriotis and C. Mitrakas. A new approach to risk 124303-7474 IJET-IJENS @ June 2012 IJENS IJENS
International Journal of Engineering & Technology IJET-IJENS Vol: 12 No: 03 53 assessment using a combined conference of the Hellenic Operational qualitative-quantitative evaluation Research Society (HELORS), 2008, pp. technique with real accidents data: 1261–1274. application on an electric power provider industry, In Proceedings, 20th national 124303-7474 IJET-IJENS @ June 2012 IJENS IJENS