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An Introduction to The Domino Effects in Process IndustriesArfaat BashirEvolution of the definitions:Third report of the AdvisoryCommittee on MajorHazards (HSE, 1984)The effects of major accidents on other plants on the site or nearby sites.Lees (1996)An event at one unit that causes a further event at another unitKhan and Abbasi (1998)A chain of accidents or situations when a fire/explosion/missile/toxic load generated by an accident in one unit in an industry causes secondary and higher order accidents in other units.Delvosalle (1998)A cascade of accidents (domino events) in which the consequences of a previous accident are increased by the following one(s), spatially as well as temporally, leading to a major accident.Vallee et al. (2002)An accidental phenomenon affecting one or more installations in an establishment which can cause an accidental phenomenon in an adjacent establishment, leading to a general increase in consequences.Lees (2005)A factor to take account of the hazard that can occur if leakage of a hazardous material can lead to the escalation of the incident, e.g. a small leak which catches fire and damages by flame impingement a larger pipe or vessel with subsequent spillage of a large inventory of hazardousmaterialAntonioni et al. (2009)The propagation of a primary accidental event to nearby units, causing their damage and further secondary accidental events, resulting in an overall scenario more severe than the primary event that triggered the escalation.The Domino EffectsThe Domino EffectsElements :1. Primary scenario: An accident scenario that starts a domino effect propagating and escalating to other process or storage units, triggering one or several secondary accident scenarios.

2. Secondary scenario: An accident scenario caused by the impact of an escalation vector generated by a primary accident scenario.

3. Propagation: In case of a spatial domino effect, the propagation indicates the involvement of other units or equipment items, present at different positions with respect to that of the primary accident. In case of a temporally domino effect, there is propagation within the same unit or equipment item.

4. Escalation: The intensification of the overall consequences of an undesired event.

5. Escalation vector: A vector of physical effects generated by the primary accident scenario.Propagation Scenarios

Simple propagation: one-to-one correspondence, that is, a single primary scenario triggering a single secondary scenario.Multilevel domino chain: A first accident scenario triggers a second accident scenario, the second accident scenario triggers a third accident scenario, and so on.Multilevel propagation: Primary accident resulted in several simultaneous secondary scenarios triggered by the first primary accident. Secondary scenarios also triggered more than one scenario.The Domino EffectsEscalation vectorsEscalation: The intensification of the overall consequences of an undesired event.Escalation is implicitly required in order to consider an accident scenario as a domino accident.Khan and Abbasi (1998), identified two main patterns for propagation and escalationDirect escalation: direct escalation is caused by the direct damage of target units due to the effect of radiation, blast waves and fragment projection.Indirect escalation: Indirect escalation scenarios may be triggered by the loss of control of units or plant sections due to the effect of the primary scenario.Direct escalation is by far the more likely and documented mechanism leading to domino accidents, as evidenced from past accident analyzes.The Domino EffectsMost common triggering events and escalation vectors Physical Effects Responsible for Escalation in 100 Domino Accidents(Cozzani et al., 2005)Escalation VectorPrimary ScenarioEventsHeat Radiation OverpressureFragmentsVCE170161Mechanical explosion170107BLEVE130013Fireball1100Jet fire8800Pool fire444400Flash fire0000The Domino Effects

Abdolhamidzadeh et al. (2011) 53% of 224 accidents involved primary plus secondary events 47% included a tertiary or even higher level escalation events.

Darbra et al. (2010) analyzed 330 domino sequences by using the relative probability event tree. Most frequent Domino SequencesThe Domino Effects

(Darbra et al. 2010) (52.4%) Explosion (47.6%) FireThe most frequent final domino sequences were:

Explosion > fire (27.6%),fire > explosion (27.5%) fire > fire (17.8%).The Domino EffectsMost frequent Domino SequencesIdentification of primary EventsAssessment of the source termConsequence analysisIdentification of possible secondary targetsDamage assessmentApproaches to domino effect assessmentSteps required for domino effect analysis.Domino accident is the result of a complex propagation and escalation process of a primary event. Thus, the identification and assessment of domino scenarios requires a detailed analysis of the consequences of the primary scenario and of the potential structural damage caused to secondary targets and the evaluation of probability and intensity of secondary scenario.The Domino EffectsA correspondence may be identified among three widely used conventional approaches to hazard and risk assessment and the corresponding level of detail required for the assessment of domino scenarios.1. Preliminary hazard analysis (PHA) is widely used in early design phases and may be applied to understand the possibility of escalation events.

2. Quantitative risk assessment (QRA) may be suitable to understand the risk due to domino scenarios, to identify hot spots or critical scenarios and regulatory purposes.

3. Distributed parameters modeling aimed at worst-case accident or maximum credible accident analysis may be carried out to assess the design basis or to obtain detailed data on a specific scenario of interest.The Domino EffectsApproaches to domino effect assessmentPreliminary analysis of domino hazardIn the PHA phase of safety assessment or when a qualitative assessment of domino hazards is required, the analysis of escalation may be carried out on the basis of a simplified assessment of primary scenarios, using threshold values for the identification of escalation targets.Requires that the primary events of interest are identified and that the consequences of the final outcomes of these primary scenarios are calculated.Possibility of escalation may be provided comparing the intensity of the escalation vector.The Domino EffectsQuantitative Risk Assessment of Domino ScenariosStandard tool to analyze and compare the risk due to industrial installationsThe analysis of a complex plant is undertaken, a huge number of possible scenarios need to be considered. It has been demonstrated that if escalation is considered for n equipment items, up to 2n different first-level domino scenarios are possible. Thus, a suitable computational approach needs to be appliedA framework for the quantitative risk assessment of domino scenarios was developed in several studies (Delvosalle, 1998; Khan and Abbasi, 1998; Abdolhamidzadeh et al., 2010; Reniers et al., 2005; Cozzani et al., 2005)The Domino EffectsTools for Assessment of Domino EffectsDOMIFFECT (DOMIno eFFECT) Software; Khan and Abbasi (1998)Computer-automated tool and the first software package specifically dealing with domino effect risk assessment. Outcomes help decision making toward strategies needed to prevent domino accidents.1. Whether domino effects are likely to occur in a given setting2. What are the likely accident scenarios3. What would be the likely impacts of the different scenarios.Approach is based on deterministic and probabilistic models to forecast the occurrence probability and damage potential of different domino scenarios. Deterministic models estimate the consequences of a wide range of scenarios.Probabilistic models assess the event frequencies in addition to damage and domino probabilities.The Domino Effects

DOMIFFECT sequential steps (Khan and Abbasi, 1998)The backbone algorithm for development of this software is a conceptual framework called domino effect analysis (DEA) presented byKhan and Abbasi (1998). Later on, in order to perform an automated DEA, these authors have developed DOMIFFECT.Few modules are similar to the modules in a previously presented software called MAXCRED-II by Khan and Abbasi in1997. The Domino module differentiates it from QRA tools.The Domino EffectsDomino Version of ARIPAR-GIS SoftwareThe Domino EffectsCozzani et al. (2006) developed and added a specific domino software package to ARIPAR-GIS software in order to boost its capabilities and handle domino QRA. ARIPAR-GIS software was developed in the framework of the ARIPAR project and is a risk assessment tool. Risk IdentificationFrequency CalculationConsequence AssessmentRisk RecompositionDomPrevPlanning (Reniers and Dullaert, 2007).Generates a simple ranking of domino sequences as an output. Uses a holistic approachDetermines the prioritization of domino sequence.

A common restraint disadvantage of domino DSS is the requirement both of numerous diverse input data and of extensive user knowledge and expertise. Reniers and Dullaert (2007) have developed a computer automated tool called DomPrevPlanning which, by using simple input data, generates a simple ranking of domino sequences as an output. DomPrevPlanning (Reniers and Dullaert, 2007).The Domino Effects

Based on the application of simulation techniques (Monte Carlo Simulation) instead than on analytical formulations.Often used when the model is highly complex, nonlinear, or involves more than just a couple of uncertain parameters.A detailed consequence assessment is necessary prior to the application of the method for calculation of frequency of primary events for each equipment and the escalation probabilities.FREEDOM: Abdolhamidzadeh et al. (2010) The Domino Effects

An introduction to The Domino Effects in Process Industries?