Hazardous material transportation poses obvious hazards to environment, general public and respon... more Hazardous material transportation poses obvious hazards to environment, general public and response personnel. In this context, risk reduction can be achieved by analyzing and designing correctly the routing of shipments, by proper risk assessment procedure. HazMat transportation risk management must include appropriate emergency response services, limiting accident consequences. This paper presents a quantitative risk assessment approach to HazMat transportation, starting from an historical statistical analysis on road accidents. A methodological approach for the assessment of standard vehicle and dangerous good truck flows was applied to a pilot area in the North of Italy, allowing a statistical reinforced evaluation of route intrinsic enhancing/mitigating parameters. The results evidence the distribution of the risk along the different routes and the localization of high spots, with good accuracy and precision. Preventive and mitigating risk measures are discussed in depth, with particular reference to the optimization of emergency equipment (number of prompt action vehicles) by means of an unambiguous and consistent selection criterion that allows reduction of intervention time. Different risk mitigation options, based on changing route or designing alternative slip roads, in transport corridors or tunnels, are investigated as well. The presented approach can represent a useful tool not only to estimate transport risk, but also to define strategies for the reduction of risk (i.e. distribution and limitation of ADR road traffic, improvement of highway section, design of alternative routes) and emergency management
In analyzing pool fires and the potential for domino effects, the evaluation of thermal radiation... more In analyzing pool fires and the potential for domino effects, the evaluation of thermal radiation and issues of interplant spacing, employees' safety zones, fire wall specifications are to be addressed on the basis of a proper consequence analysis. Fire evolution can behave in different ways, according to the characteristics of the liquid pool and interactions with the surroundings. We face the modelization of an atypical scenario, consisting of a pool fire of coal tar, a multi-component mixture, with hydrocarbon components characterized by a broad range of normal boiling points, under semi-confined geometry. Analytical solution of energy and mass balances is approached by considering "hydrocarbon key components". A peculiar novelty of the approach is that the physical model of the pool is solved to provide a description of a variable heat emitting flame area, as a function of the vertical flame axis, up to a limiting value. In order to evidence the effective potential...
Journal of Loss Prevention in the Process Industries, 2005
... the graph-theory, recently introduced by Beroggi and Wallace (1994) in computing optimal cour... more ... the graph-theory, recently introduced by Beroggi and Wallace (1994) in computing optimal course of action for emergency response. ... After a comparative survey on various shortest path algorithms (Dreyfus, 1969) we considered the Dijkstra algorithm (Dijkstra, 1959) of label ...
In this paper, a comparative study of different dispersion models considering stack emissions fro... more In this paper, a comparative study of different dispersion models considering stack emissions from a coal- fired power plant. Modelling comparison study was performed utilizing Safe-Air II, a reliable Lagrangian model and ADMS 5adopting a skewed Gaussian representation. Fallouts were estimated starting from the statistical elaboration of meteorological data of the year 2012.Results evidenced a satisfactory agreement with measured data from monitoring stations, both in the discrete values and in the monthly and hourly averages. Furthermore, within an impact radius 40 km from the source, the areas of highest and lowest fallouts were identified in order to explore the possibility of considering lichens as potential bio-monitors, being well established their sensitivity to SO2 and eventual damage to the thalli.
Normative legislations relating to standards and international guidelines within the framework of... more Normative legislations relating to standards and international guidelines within the framework of carbon capture sequestration (CCS) and the transport of carbon dioxide in the actual operating conditions are still under development. The focus of the present study is the cold jet modelling, including the orientation factor, representing a scenario still partially unexplored. The framework provides by simple analytical formulae the boundaries of the jet region and air entrainment behaviour, as well as the resulting ground level hazardous concentrations to humans. The model relies on a first experimental validation of the jet phase, evidencing that the model can be applied, at least as a first cautious screening tool, for safety distance evaluation.
As widely reported in the scientific literature, audits, benchmarking, safety performance indicat... more As widely reported in the scientific literature, audits, benchmarking, safety performance indicators and accident data help the management to understand the current safety performance status and to individuate strong and weak areas of the safety management system. Additionally, being process safety incidents relatively rare, as evidenced in the Baker report on BP Texas City accident, safety performance cannot be measured effectively alone on the basis of such high profile incidents. In the first phase of the research program, process and occupational injuries were studied, collecting field data in a large process industry, over five-year observation. Technical and management improvements seem no longer sufficient to promote safety as at-risk behaviour and unsafe attitudes are still present in spite of all training, supervision and guidance. A thorough analysis on underlying causes connected with human failure was subsequently performed by designing a structured questionnaire, for bo...
In large-scale construction projects, site situation and surrounding environment can change daily... more In large-scale construction projects, site situation and surrounding environment can change daily. This is due to multiple factors acting as "incident catalysts", like less, or un-skilled workers, outsourcing, more complex construction phases (heights or confined spaces), under pressure working conditions, as well as changes in environmental conditions (e.g. wind, temperature, etc.). It is essential to acquire a statistical significant reference concerning the unsafe acts and risky behaviour to implement proactive measures preventing occurrences of major incidents. In this paper, the construction phase in the Middle East of one of the world's largest oil and petrochemical integrated complex was considered. Starting from the accident/incident pyramid approach, management, direct field supervisors, as well as subcontractors were involved in the development and upgrading of a Multilayer Reporting System, covering any risk behaviours, unsafe situation, violations or acts, ...
As amply known, hydrogen plays a very significant role in the process industry exerting a vital f... more As amply known, hydrogen plays a very significant role in the process industry exerting a vital functionality in oil refineries, namely for secondary level refining units such hydro-treating and hydrocracking sections. This paper starts from a statistical analysis on hydrogen accidents and a thorough investigation on the sequence and causes of an accident involving a hydrogen leakage in a downstream oil industry. We present some key features of the accident and comment some practical implications for setting up risk reduction options at the plant level. The applicative phase of the paper states the main prevention strategies and suggest possible mitigation measures for hydrogen leaks events, discussing some practical solutions applied in the design of a large refinery. The experience and lessons learned gained from the event investigation and the comparison of the accident with the predictions of the safety report leads to the formulation of proposals and design modifications aiming...
... be grouped as follows: lack of training or instruction; lack of motivation; lack of physical ... more ... be grouped as follows: lack of training or instruction; lack of motivation; lack of physical or ... On the other hand, dealing with the Finnish construction and manufacturing industries in the period ... protection can be carried out directly by the employer; namely the artisan and industrial ...
Simulation of a process by means of physical models at a reduced scale is an essential tool in ma... more Simulation of a process by means of physical models at a reduced scale is an essential tool in many application, allowing to perform a large number of experimental runs, so as to obtain a quantitative representation of the involved phenomena, at relatively low cost. Some difficulties can arise when the mathematical model derived from the simulation is applied to a real scale problem, in that the scaling of some empirical coefficients with the system size is not obvious at all. As fluid barrier scaling is a difficult task, still not deeply investigated in the scientific literature, the focus of this study is to translate knowledge from research on this topic into practice for industrial application. Following an extensive and accurate experimental work in wind tunnel, the main parameters determining the effectiveness of containment, absorption and dilution of chlorine releases were determined and a mathematical model is developed. In order to frame proper scale-up strategies, the most important result of this study rests on the explicit formulae giving, as a function of the aforesaid parameters, the single pass efficiency, the global absorption efficiency, and the toxic gas concentration downwind the barrier. In the far field, the gas concentration is practically determined only by the rate of atmospheric dispersion of the mass flow-rate of gas escaping the abatement. The absorption efficiencies are related to the drop size and to the mass transfer coefficients in the gas and liquid phases. The mean drop diameter plays an essential role in the absorption efficiency, since it simultaneously acts on air entrainment, interfacial surface and mass transfer coefficient in the gas phase. The evaluation of the mitigation effect for an industrial installation requires the scaling of the entrainment coefficient experimentally determined from wind tunnel testing. All the scaling criteria needed for adapting the proposed model to the design of a spray curtain suitable for the protection from a chlorine release, are amply discussed presenting some carefully designed simulations. Owing to its rather general structure, the model can be applied to different gaseous releases and/or absorbing solutions, provided that proper values of the parameters related with the chemical and physical absorption of the involved substances be theoretically or experimentally obtained in advance.
Journal of Loss Prevention in the Process Industries, 2007
A simple n-compartment mathematical model is developed to study the effectiveness of fluid curtai... more A simple n-compartment mathematical model is developed to study the effectiveness of fluid curtains and transient behaviour in mitigating the effects of an accidental chlorine release. The model is obtained considering chemical and physical absorption effectiveness of the toxic cloud by a reacting liquid curtain. The characteristics of the curtain and the evolution were deeply studied by means of replicated
In this article experimental and theoretical investigations on liquid spray curtains are presente... more In this article experimental and theoretical investigations on liquid spray curtains are presented, in the context of absorbing and dispersing accidental releases of chlorine in air. A mathematical model of a two-phase jet is developed to evaluate the entrained air rate in connection with the liquid flow rate. The model was successfully compared by means of replicated wind tunnel experimental runs adopting spray nozzles suitable to create a two-blade barrier. The experimental work demonstrated that it is possible to distinguish two regions in the barrier. One region is dominated by the liquid inertia and is comparable to an airplane jet. The other region is dominated by gravitational effects, and its dimensions do not vary appreciably. An analytical solution to the problem is obtained, taking into account the instantaneous and nonreversible chemical reactions, i.e., chlorine absorption in alkaline solutions, in the case of still air. The developed methodology could be applied to more complex situations, allowing the attainment of a more generalized approach for the design of a curtain given the release parameters, the site layout, and vulnerable target specifications.
Notwithstanding the enforcement of ATEX EU Directives (94/9/EC of 23 March 1994) and safety manag... more Notwithstanding the enforcement of ATEX EU Directives (94/9/EC of 23 March 1994) and safety management system application, explosions in the coal sector still claim lives and cause huge economic losses. Even a consolidated activity like coke dry distillation allows the opportunity of preventing explosion risk connected to fugitive emissions of coke oven gas. Considering accidental releases under semi-confined conditions, a simplified mathematical approach to the maximum allowed gaseous build-up is developed on the basis of the intrinsic hazards of the released compound. The results will help identifying and assessing low rate release consequences therefore to setup appropriate prevention and control measures. The developed methodology was tested at the real-scale and validated by numerical computational fluid dynamics (CFD) simulations showing the effectiveness of the methodology to evaluate and mitigate the risk connected to confined hazardous releases.
An important feature of tank pool fire is that the targets of interest for critical effects may i... more An important feature of tank pool fire is that the targets of interest for critical effects may include other plant units, such gas pipelines, storage sites, process sections, with heat transfer modes not limited to radiation. This paper, which takes inspiration from a recent work of the same authors, considers the physical model of a rectangular pool-fire to provide an analytical trend of the surface emissive power depending on the flame height. The capability of the approach is proved by an applicative case-study where the possible escalation from pool fire to a coke oven gas pipeline failure is analysed, within the context of a coal dry distillation plant. The possibility of escalation with pipeline damage is thoroughly discussed, in order to develop a detailed design of the emergency response capability considering the provision of human and logistical resources.Keywords: accident escalation, coal, coal tar, coke oven gas, explosion, pool
Hazardous material transportation poses obvious hazards to environment, general public and respon... more Hazardous material transportation poses obvious hazards to environment, general public and response personnel. In this context, risk reduction can be achieved by analyzing and designing correctly the routing of shipments, by proper risk assessment procedure. HazMat transportation risk management must include appropriate emergency response services, limiting accident consequences. This paper presents a quantitative risk assessment approach to HazMat transportation, starting from an historical statistical analysis on road accidents. A methodological approach for the assessment of standard vehicle and dangerous good truck flows was applied to a pilot area in the North of Italy, allowing a statistical reinforced evaluation of route intrinsic enhancing/mitigating parameters. The results evidence the distribution of the risk along the different routes and the localization of high spots, with good accuracy and precision. Preventive and mitigating risk measures are discussed in depth, with particular reference to the optimization of emergency equipment (number of prompt action vehicles) by means of an unambiguous and consistent selection criterion that allows reduction of intervention time. Different risk mitigation options, based on changing route or designing alternative slip roads, in transport corridors or tunnels, are investigated as well. The presented approach can represent a useful tool not only to estimate transport risk, but also to define strategies for the reduction of risk (i.e. distribution and limitation of ADR road traffic, improvement of highway section, design of alternative routes) and emergency management
In analyzing pool fires and the potential for domino effects, the evaluation of thermal radiation... more In analyzing pool fires and the potential for domino effects, the evaluation of thermal radiation and issues of interplant spacing, employees' safety zones, fire wall specifications are to be addressed on the basis of a proper consequence analysis. Fire evolution can behave in different ways, according to the characteristics of the liquid pool and interactions with the surroundings. We face the modelization of an atypical scenario, consisting of a pool fire of coal tar, a multi-component mixture, with hydrocarbon components characterized by a broad range of normal boiling points, under semi-confined geometry. Analytical solution of energy and mass balances is approached by considering "hydrocarbon key components". A peculiar novelty of the approach is that the physical model of the pool is solved to provide a description of a variable heat emitting flame area, as a function of the vertical flame axis, up to a limiting value. In order to evidence the effective potential...
Journal of Loss Prevention in the Process Industries, 2005
... the graph-theory, recently introduced by Beroggi and Wallace (1994) in computing optimal cour... more ... the graph-theory, recently introduced by Beroggi and Wallace (1994) in computing optimal course of action for emergency response. ... After a comparative survey on various shortest path algorithms (Dreyfus, 1969) we considered the Dijkstra algorithm (Dijkstra, 1959) of label ...
In this paper, a comparative study of different dispersion models considering stack emissions fro... more In this paper, a comparative study of different dispersion models considering stack emissions from a coal- fired power plant. Modelling comparison study was performed utilizing Safe-Air II, a reliable Lagrangian model and ADMS 5adopting a skewed Gaussian representation. Fallouts were estimated starting from the statistical elaboration of meteorological data of the year 2012.Results evidenced a satisfactory agreement with measured data from monitoring stations, both in the discrete values and in the monthly and hourly averages. Furthermore, within an impact radius 40 km from the source, the areas of highest and lowest fallouts were identified in order to explore the possibility of considering lichens as potential bio-monitors, being well established their sensitivity to SO2 and eventual damage to the thalli.
Normative legislations relating to standards and international guidelines within the framework of... more Normative legislations relating to standards and international guidelines within the framework of carbon capture sequestration (CCS) and the transport of carbon dioxide in the actual operating conditions are still under development. The focus of the present study is the cold jet modelling, including the orientation factor, representing a scenario still partially unexplored. The framework provides by simple analytical formulae the boundaries of the jet region and air entrainment behaviour, as well as the resulting ground level hazardous concentrations to humans. The model relies on a first experimental validation of the jet phase, evidencing that the model can be applied, at least as a first cautious screening tool, for safety distance evaluation.
As widely reported in the scientific literature, audits, benchmarking, safety performance indicat... more As widely reported in the scientific literature, audits, benchmarking, safety performance indicators and accident data help the management to understand the current safety performance status and to individuate strong and weak areas of the safety management system. Additionally, being process safety incidents relatively rare, as evidenced in the Baker report on BP Texas City accident, safety performance cannot be measured effectively alone on the basis of such high profile incidents. In the first phase of the research program, process and occupational injuries were studied, collecting field data in a large process industry, over five-year observation. Technical and management improvements seem no longer sufficient to promote safety as at-risk behaviour and unsafe attitudes are still present in spite of all training, supervision and guidance. A thorough analysis on underlying causes connected with human failure was subsequently performed by designing a structured questionnaire, for bo...
In large-scale construction projects, site situation and surrounding environment can change daily... more In large-scale construction projects, site situation and surrounding environment can change daily. This is due to multiple factors acting as "incident catalysts", like less, or un-skilled workers, outsourcing, more complex construction phases (heights or confined spaces), under pressure working conditions, as well as changes in environmental conditions (e.g. wind, temperature, etc.). It is essential to acquire a statistical significant reference concerning the unsafe acts and risky behaviour to implement proactive measures preventing occurrences of major incidents. In this paper, the construction phase in the Middle East of one of the world's largest oil and petrochemical integrated complex was considered. Starting from the accident/incident pyramid approach, management, direct field supervisors, as well as subcontractors were involved in the development and upgrading of a Multilayer Reporting System, covering any risk behaviours, unsafe situation, violations or acts, ...
As amply known, hydrogen plays a very significant role in the process industry exerting a vital f... more As amply known, hydrogen plays a very significant role in the process industry exerting a vital functionality in oil refineries, namely for secondary level refining units such hydro-treating and hydrocracking sections. This paper starts from a statistical analysis on hydrogen accidents and a thorough investigation on the sequence and causes of an accident involving a hydrogen leakage in a downstream oil industry. We present some key features of the accident and comment some practical implications for setting up risk reduction options at the plant level. The applicative phase of the paper states the main prevention strategies and suggest possible mitigation measures for hydrogen leaks events, discussing some practical solutions applied in the design of a large refinery. The experience and lessons learned gained from the event investigation and the comparison of the accident with the predictions of the safety report leads to the formulation of proposals and design modifications aiming...
... be grouped as follows: lack of training or instruction; lack of motivation; lack of physical ... more ... be grouped as follows: lack of training or instruction; lack of motivation; lack of physical or ... On the other hand, dealing with the Finnish construction and manufacturing industries in the period ... protection can be carried out directly by the employer; namely the artisan and industrial ...
Simulation of a process by means of physical models at a reduced scale is an essential tool in ma... more Simulation of a process by means of physical models at a reduced scale is an essential tool in many application, allowing to perform a large number of experimental runs, so as to obtain a quantitative representation of the involved phenomena, at relatively low cost. Some difficulties can arise when the mathematical model derived from the simulation is applied to a real scale problem, in that the scaling of some empirical coefficients with the system size is not obvious at all. As fluid barrier scaling is a difficult task, still not deeply investigated in the scientific literature, the focus of this study is to translate knowledge from research on this topic into practice for industrial application. Following an extensive and accurate experimental work in wind tunnel, the main parameters determining the effectiveness of containment, absorption and dilution of chlorine releases were determined and a mathematical model is developed. In order to frame proper scale-up strategies, the most important result of this study rests on the explicit formulae giving, as a function of the aforesaid parameters, the single pass efficiency, the global absorption efficiency, and the toxic gas concentration downwind the barrier. In the far field, the gas concentration is practically determined only by the rate of atmospheric dispersion of the mass flow-rate of gas escaping the abatement. The absorption efficiencies are related to the drop size and to the mass transfer coefficients in the gas and liquid phases. The mean drop diameter plays an essential role in the absorption efficiency, since it simultaneously acts on air entrainment, interfacial surface and mass transfer coefficient in the gas phase. The evaluation of the mitigation effect for an industrial installation requires the scaling of the entrainment coefficient experimentally determined from wind tunnel testing. All the scaling criteria needed for adapting the proposed model to the design of a spray curtain suitable for the protection from a chlorine release, are amply discussed presenting some carefully designed simulations. Owing to its rather general structure, the model can be applied to different gaseous releases and/or absorbing solutions, provided that proper values of the parameters related with the chemical and physical absorption of the involved substances be theoretically or experimentally obtained in advance.
Journal of Loss Prevention in the Process Industries, 2007
A simple n-compartment mathematical model is developed to study the effectiveness of fluid curtai... more A simple n-compartment mathematical model is developed to study the effectiveness of fluid curtains and transient behaviour in mitigating the effects of an accidental chlorine release. The model is obtained considering chemical and physical absorption effectiveness of the toxic cloud by a reacting liquid curtain. The characteristics of the curtain and the evolution were deeply studied by means of replicated
In this article experimental and theoretical investigations on liquid spray curtains are presente... more In this article experimental and theoretical investigations on liquid spray curtains are presented, in the context of absorbing and dispersing accidental releases of chlorine in air. A mathematical model of a two-phase jet is developed to evaluate the entrained air rate in connection with the liquid flow rate. The model was successfully compared by means of replicated wind tunnel experimental runs adopting spray nozzles suitable to create a two-blade barrier. The experimental work demonstrated that it is possible to distinguish two regions in the barrier. One region is dominated by the liquid inertia and is comparable to an airplane jet. The other region is dominated by gravitational effects, and its dimensions do not vary appreciably. An analytical solution to the problem is obtained, taking into account the instantaneous and nonreversible chemical reactions, i.e., chlorine absorption in alkaline solutions, in the case of still air. The developed methodology could be applied to more complex situations, allowing the attainment of a more generalized approach for the design of a curtain given the release parameters, the site layout, and vulnerable target specifications.
Notwithstanding the enforcement of ATEX EU Directives (94/9/EC of 23 March 1994) and safety manag... more Notwithstanding the enforcement of ATEX EU Directives (94/9/EC of 23 March 1994) and safety management system application, explosions in the coal sector still claim lives and cause huge economic losses. Even a consolidated activity like coke dry distillation allows the opportunity of preventing explosion risk connected to fugitive emissions of coke oven gas. Considering accidental releases under semi-confined conditions, a simplified mathematical approach to the maximum allowed gaseous build-up is developed on the basis of the intrinsic hazards of the released compound. The results will help identifying and assessing low rate release consequences therefore to setup appropriate prevention and control measures. The developed methodology was tested at the real-scale and validated by numerical computational fluid dynamics (CFD) simulations showing the effectiveness of the methodology to evaluate and mitigate the risk connected to confined hazardous releases.
An important feature of tank pool fire is that the targets of interest for critical effects may i... more An important feature of tank pool fire is that the targets of interest for critical effects may include other plant units, such gas pipelines, storage sites, process sections, with heat transfer modes not limited to radiation. This paper, which takes inspiration from a recent work of the same authors, considers the physical model of a rectangular pool-fire to provide an analytical trend of the surface emissive power depending on the flame height. The capability of the approach is proved by an applicative case-study where the possible escalation from pool fire to a coke oven gas pipeline failure is analysed, within the context of a coal dry distillation plant. The possibility of escalation with pipeline damage is thoroughly discussed, in order to develop a detailed design of the emergency response capability considering the provision of human and logistical resources.Keywords: accident escalation, coal, coal tar, coke oven gas, explosion, pool
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Papers by Fabio Currò