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In this study, the Fire Dynamics Simulator (FDS) is adopted to simulate tank and dike pool fires in a tank farm. These simulations are performed in order to evaluate the potential for secondary fire events in nearby storage tanks based on the resulting incident radiative heat flux. As a precursor to the tank farm fire scenario case studies, the model is compared with experimental data of 1 m crude oil pool fire and 30 m and 50 m diameter kerosene pool fires. These comparisons are made to validate the modeling approach ahead of the application of the modeling to a problem of practical interest. The results of the FDS are consistent with experimental data. The FDS results indicate that the studied dike pool fire has the potential of triggering the domino effects in the tank farm, but not so true in the case of the tank fire. Quantitative results obtained by FDS modeling can be used in quantitative risk assessment of a tank farm and determination of safe inter-tank separation distances.

A coupled fluid-structure-fracture approach incorporating a high-efficiency detonation modeling algorithm was proposed to study the consequences of premixed flammable gas explosion occurring in pipe. A strain-rate-dependent failure criterion which is the vital prerequisite for accurate consequences prediction was derived based on the failure mechanism of materials at high strain rates and it was applied to account for the fracture of pipe. The simulated pressure time history and fracture patterns were validated against experimental results and good agreements were acquired. The interaction between detonation wave and pipe during crack extension, dynamic fracture processes of pipes with different initial flaws, venting features of detonation products and pressure profiles out of pipe were obtained and discussed in detail. The comparison with existing semi-empirical and CFD methods was performed and it is revealed that the deformation and fracture of pipe have obvious negative influences on the peak overpressure and the rate of pressure increase out of pipe. Because the energy absorption and dissipation due to structural deformation and fracture are well taken into account, the coupled fluid-structure-fracture method is expected to provide more rational consequences prediction and analysis results.

International audience; The dynamic response of benzene alkylation process to a set of deviations is analyzed with Aspen Plus Dynamics. A quantitative risk assessment is developed through simulations of deviation scenarios. The process comprises a reactor and three distillation columns with a recycle stream. The simulation scenarios are determined according to lessons learnt from accidents. This study underlines the conditions that induce an overpressure or a flooding in a distillation column. Three scenarios are proposed: feed flowrate variations, coolant flowrate reduction and cooling of the reboiler steam. Thereafter, the results allow calculating a set of risk indexes related to flooding and overpressure phenomena. This study underlines the deviation propagation effects that can be expected in all the process equipment. Moreover, it represents a significant contribution to the definition of the process control strategy and the necessary safety barriers.

Different kinds of derivative accidents due to reaction runaway happen frequently. The research and the prediction of such accidents and their consequences are useful in the determination of safety distances and the establishment of emergency plan. The present paper takes into account the complex components and their dynamic change in the reactor, and proposes a new quantitative analysis method for the derivative accident consequences of reaction runaway. The so-called “simulated process for derivative accidents of reaction runaway” (SPDA-RR), based on the logic diagram of accident judgement, relies on Aspen Plus to describe the process simulation. The hazard analysis of such accidents involves many mathematical models for overpressure explosion, fireball, vapor cloud explosion, harmful gas dispersion, etc. The governing parameters of the mixture used in the mathematical models, such as the component content, temperature, pressure, enthalpy and entropy, can be obtained from SPDA-RR. Furthermore, in order to analyze other cases of reaction runaway, this SPDA-RR can be easily extended by an adequate parameter adjustment.

Although spill incidents at loading and unloading facilities account for only 4% of the chemical accidents that occurred in Korea during the last four years, the increase is incremental each year. Loading and unloading facilities are equipped with trenches in preparation for mass drainage because transports by vehicle are frequent and physical blocking is difficult when a release accident occurs. Particularly, in the case of a chemical release with a high vapor pressure, the trench is effective to mitigate accidents by reducing the liquid surface to primarily prevent dispersion. This study proposes an improved trench system that can effectively and rapidly withdraw large amounts of chemicals spilled from transport vehicles. Assuming a total volume leakage of a 55% hydrofluoric acid (HFA) solution from a transport vehicle, the study confirmed the risk-reducing effect by comparing using the consequence analysis program (ALOHA) and Probit analysis. The results show that minimizing the time that the released chemicals stay in the trench using control system (pH meter and automatic valve) can reduce the amount of chemicals vaporizing, thereby minimizing the effect distance of the release incident.

Chemical accidents generated during maintenance, repair, and normal operation, such as dispersion, fire, and explosions, can cause massive losses within and outside workplaces. Since a 2012 hydro fluorine leak in Gumi, South Korea, many studies have investigated mitigation systems for reducing accident impact. However, due to potential costs, and lack time and expertise, most companies have hesitated to install mitigation systems without accurate impact evaluations. Therefore, it is essential to analyze mitigation system efficacy under various possible accident scenarios. We considered a mitigation system incorporating a reserve vessel installed next to a storage vessel. When a leakage accident occurs, the chemical in the main vessel is transferred to the reserve vessel by a pump. Simulation results based on Torricellis’ theorem indicate that this mitigation system could significantly reduce leakage, and reduce leakage consequences in terms of maximum diffusion distance and hazardous gas concentrations based on consequence analysis.

The intent of this paper will be to review the methods utilized at the Eastman Kingsport site in determining magnitude of consequences of toxic, thermal, and blast overpressure scenarios. This will include discussion on dispersion modeling, dose-response methods for toxic, and thermal probits as well as assessing occupant vulnerability through the use of BakerRisk's Explosion Risk Cooperative tools. © 2017 American Institute of Chemical Engineers Process Saf Prog, 2017

In place of traditional empirical methodologies, computational fluid dynamics (CFD) is used for more accurate consequence modelling as it takes into account of geometrical obstructions. However, its use is costly and not practical for large-scale use in the industry. The present paper explores the integration of design of experiments and surrogate modelling methodologies to enhance the use of CFD-based consequence models. A new integrated methodology is applied to a case study of liquefied natural gas (LNG) pool fire, showing the challenges of training and evaluation of large-scale surrogate models. This study investigates the differences between using a non-linear global surrogate model (namely, least-squares support vector machines) and a linear piece-wise surrogate model (namely, linear nearest neighbour interpolation), as well as the use of sequential sampling algorithm as a means of improving overall surrogate accuracy. The results are analysed and localization of surrogate error regions is discussed in the paper. The new integrated methodology shows potential in improving the way consequence analysis is performed, and it could be an enabler of real-time risk monitoring systems.

Hydrogen is one of the most suitable solutions to replace hydrocarbons in the future. Hydrogen consumption is expected to grow in the next years. Hydrogen liquefaction is one of the processes that allows for increase of hydrogen density and it is suggested when a large amount of substance must be stored or transported. Despite being a clean fuel, its chemical and physical properties often arise concerns about the safety of the hydrogen technologies. A potentially critical scenario for the liquid hydrogen (LH2) tanks is the catastrophic rupture causing a consequent boiling liquid expanding vapour explosion (BLEVE), with consequent overpressure, fragments projection and eventually a fireball. In this work, all the BLEVE consequence typologies are evaluated through theoretical and analytical models. These models are validated with the experimental results provided by the BMW care manufacturer safety tests conducted during the 1990's. After the validation, the most suitable methods are selected to perform a blind prediction study of the forthcoming LH2 BLEVE experiments of the Safe Hydrogen fuel handling and Use for Efficient Implementation (SH2IFT) project. The models drawbacks together with the uncertainties and the knowledge gap in LH2 physical explosions are highlighted. Finally, future works on the modelling activity of the LH2 BLEVE are suggested.

This study investigated the critical issues for determining the design accidental load (DAL) fire procedure based on quantitative risk assessment (QRA) for offshore installations. Considerable attention was paid to parametric uncertainty in choosing the numerical values used for the frequency and consequence analysis. In particular, selecting the initial leak size was one of the most critical aspects, and inconsistent approaches for selecting this value resulted in different risks for identical systems. Frequency analysis of past investigations also overlooked the inaccuracy and unsuitability of statistical data. Accordingly, the estimated risks were significantly uncertain, and the lack of information about the results increased the risk of making the wrong decision. In this study, the Latin hypercube sampling (LHS) technique was used to treat parametric uncertainty in QRA. Different fire exceedance curves and DAL fires were demonstrated by selecting different sets of representative values. The distribution and confidence interval of the DAL fires showed a wide distribution with varying uncertain and critical parameters. Therefore, this procedure provided quantitative information on inherent uncertainty, and such additional information regarding DAL fires can lead to better decision making.

Upon completion of a facility siting study, a major step in the critical path for implementation is acceptance from upper management on the remediation plan. Communicating with upper management occurs at the end of several steps which can be strategically mapped in order to maximize upper management's understanding of the needs of a site's remediation requirements. Using an example chemical plant, this paper will detail the process of initiating a facility siting study, provide a novel approach to prioritizing building remediation requirements, and discuss how the resulting information can best be framed and communicated to upper management. In addition to discussing strategies for effective communication with upper management on proposed facility siting strategies, the paper also details an online system that could be used for keeping facility siting data evergreen after the study is completed. © 2016 American Institute of Chemical Engineers Process Saf Prog 36: 158–164, 2017

On December 7, 2009, a 50-foot-tall high-pressure vessel ruptured in the Nihon Dempa Kogyo Crystal, Inc. facility in Belvidere, Illinois. Several projectiles rapidly traveled outward from the facility, killing a truck driver 650 feet away and injuring an employee in another building 435 feet away. This paper summarizes the lessons learned from this incident both on causal and consequential aspects. Stress corrosion cracking was identified as the failure mechanism by the U.S. Chemical Safety and Hazard Investigation Board. After analyzing the operating conditions and the aftermath, this incident has been identified as a Boiling Liquid Expanding Vapor Explosion (BLEVE) under a supercritical pressure. A consequence analysis of the incident is performed where overpressure and fragment distance are calculated, together with safety distance estimation. Additionally, other safety-related problems, such as safety culture, management inside the corporation, and communication between this facility and the government are discussed.

The Risk Based Inspection (RBI), proposed by the American Petroleum Institute, is actually the highest benefit maintenance guidelines in the chemical industry, but data collection that characterises this analysis is very complex and time-consuming. The support of the RBI module of the Inspection Manager software helps in overcoming such issues as it encloses all functionalities for an easier management of technical data in the Plant's Inspection. The objective of this work is to test the newer version of the RBI module, to achieve this aim some quantitative examples were examined. In addition, by means of the support of such a module, results of the consequence assessment were also compared with those obtained by two commercial softwares in order to verify the Inspection Manager 's support in risk-based decisions also when methods for frequency and consequence assessment, different than those of API RBI, are applied and to comment about the available approaches for the consequence analysis.

On March 21, in Xiangshui County, Yancheng city, China, a catastrophic explosion occurred at Tianjiayi Chemical Co., Ltd. that caused 78 deaths and injured more than 617 individuals, with a property loss of as much as US$ 100 million. An explosion crater with a diameter of 98 m was generated. An extensive consequence analysis based on the crater size and physical effects for the estimation of the quantity of exploded dinitrobenzene (DNB) was performed. By using the position recorded in the satellite photo and the layout of the plant, the crater site was determined to be located near a warehouse where dinitrobenzene was stored. From the scaling law associating the TNT equivalent with crater diameter, the TNT equivalent of exploded ditrobenzene was determined to be approximately 708 tons. Based on the results of the consequence analysis performed by three methodologies, it can be concluded that the Tianjiayi Chemical Co. warehouse not only stored a substantially large quantity of dinitrobenzene but was also located too close to adjacent structures without an adequate separation distance. Judging by the effect of explosive blast on personnel, a fatality radius was determined to be about 400 m from the explosion center.

While several dispersion modeling tools provide modeling tools for static situations, it is challenging to model conditions when there are several variables continually changing. This article discusses several modeling approaches to solve the source term of a release event, including: tracking the concentration of vapor inside of a structure; accounting for heat of solution of a leak of strong acid while deluge is applied; and modeling the output from a scrubber given a dynamic input stream. Upon development of the source term, a method for applying the source term to common dispersion modeling packages is explained. © 2016 American Institute of Chemical Engineers Process Saf Prog 35: 392–398, 2016

Facility siting studies have been a requirement for many years, specifically for facilities that must comply with OSHA's PSM program. Facility siting is frequently interpreted as performing a building siting study which adheres to the guidance given in API RP 752. Many of the siting studies conducted for large facilities over the past few decades have focused on explosion overpressure impacts to occupied buildings, with more simplistic evaluations for fire and toxic gas impacts. Toxic gas impact analyses often only evaluate the potential exposure of a building location, to a specific gas concentration, and do not evaluate the level of infiltration into the building where occupants may be impacted. Infiltration of flammable gases has largely been ignored in most building siting studies. Despite this oversight, this hazard is one which should be addressed when following the guidance found within API RP 752. Through the use of dispersion modeling and infiltration analyses, the hazards associated with flammable or toxic gas infiltration can be incorporated into a building siting study. This article outlines the process of conducting a building siting study in accordance with API RP 752, with specific emphasis on the consequence analysis for infiltration analyses. © 2015 American Institute of Chemical Engineers Process Saf Prog, 2015

An explosion overpressure analysis is a routine part of compliance with the American Petroleum Institute (API) Recommended Practice (RP) 752 and 753. A basic consequence analysis often attempts to demonstrate a few scenarios that may appear to have the most extreme consequences; however, these scenarios may also have extremely low likelihoods of occurrence. To have a better understanding of how likely as well as how extreme a consequence may be, risk-based analysis is often required. One method used for this is an overpressure exceedance analysis which uses overpressure results from many potential explosion scenarios coupled with the probability of each scenario. Pressure–impulse curves can make better use of the explosion model's outputs (pressure and impulse) in order to predict building damage and possible impacts to personnel. Using this type of analysis with a building damage–fatality relationship, an F–N style curve can be created which shows the cumulative frequency vs. the number of potential fatalities. Generation of F–N curves can help to better define the risks to building occupants, provide an additional means of evaluating a building's acceptability, and can serve as a part of a quantitative risk analysis (QRA) for facility personnel. This paper will discuss the method used to predict the probabilities of building occupant fatalities for use in an F–N curve, as well as the benefits and potential problems with this type of analysis.

Determining if and when a vessel and/or piping component is going to fail under fire exposure and/or from cold temperature embrittlement is an important factor in consequence analysis and risk assessment. This article describes detailed methods for establishing the conditions for vessel/piping failure and whether the material of construction for vessels and piping is properly selected for fire exposure and/or cold depressuring/relief. Several case studies are used to illustrate important concepts dealing with how wall temperatures should be calculated for single and multiphase systems in order to establish if a vessel and/or a piping component is going to fail. © 2014 American Institute of Chemical Engineers Process Saf Prog 34: 64–71, 2015

Ensuring personnel can safely shelter during a chemical release is critical. The probit function is useful in determining maximum safe sheltering time. Probits provide a link between probability of expected response and the exposure of a population to a specific event. Probit analysis can provide an estimate of the percentage of sheltered occupants with potential for adverse response to a chemical release. Probits can be used to estimate duration of exposure for probability of nuisance-level response, loss of consciousness, or fatal exposures. Dispersion modeling tools provide data on predicted effects in response to long-term exposure (typically 1 h). However, these tools do not define the maximum allowable exposure time for building occupants before loss of consciousness or fatalities are seen. This article provides methodology for estimating critical exposure duration. This article provides a methodology with existing MS Excel formulas in measuring probits to arrive at probability of response to a toxic release. While data on probit values for some chemicals is readily available, there is minimal guidance in the open literature on developing estimates of probit constants where they do not currently exist or are not published. This article presents a methodology for estimating probit constants based on toxicological data. © 2014 American Institute of Chemical Engineers Process Saf Prog 34: 58–63, 2015

Petrochemical complexes include high risk interconnected plants processing large quantities of dangerous/flammable substances, complex reactors of high thermal sensitivity operated under severe conditions of high productivity and associated equipment, vessels or separation units operating at intense temperature and pressures. Such plant design/operation problems contribute quite frequently to the occurrence of small incidents or rare major accidents including domino effects. The study applies classical boiling liquid expanding vapour explosion fire and toxic puff release models to evaluate the effects and consequences of different accident scenarios involving two neighbouring risk plants, with exemplifications for the aniline and maleic anhydride synthesis plants. A proposed joint probability index of human casualties, related to thermal radiation doses and toxic material released around plants, points out the influence of production capacity and plant proximity on the severity of accident consequences and domino-effect occurrence. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.

It is very important and necessary to perform quantitative hazard analysis for possible accidental leakage from an underground gas storage cavern in salt rock. An integrated quantitative hazard analysis method for natural gas jet release from salt caverns is presented in this paper, which was constituted by a revised model for gas leakage rate calculation, a consequence analysis and a model of probability assessment for harm. The presented method was validated by comparing the analytical results with the data collected from the real accidents (including the leakage, jet fire, fireball and vapor cloud explosion). It is indicated that the proposed method was more accurate than the TNT equivalence method for vapor cloud explosion and gave more reasonable results when applied to the consequence analysis for the thermal radiation from jet fire and fireball.

In the nitrogen fertilizer industry, potentially severe impacts can stem from toxic, fire, and explosion hazards from accidental releases and hazards associated with failures in high pressure equipment. While consequence analysis can be used to calculate the severity (as measured by the personnel or buildings in the hazard zone), the very large zones associated with some of the most severe scenarios essentially place the entire facility within the hazard zone, leaving few practical options to mitigate the consequence. Using a quantitative risk analysis approach, which evaluates both the consequence and likelihood of potential events at fertilizer sites, provides additional insight to help make informed decisions about the best way to minimize the risk exposure. © 2012 American Institute of Chemical Engineers Process Saf Prog, 2012

The methodologies in the chapter on “Dispersion Modeling” in the CCPS book Guidelines for Consequence Analysis of Chemical Releases provide means for modeling outdoor releases at relatively long distances from a large source. At times it is necessary to model releases at relatively short distances from a small source. Making the assumption that the model as developed is valid at the near range, it was used to estimate the levels of ethanol that are emitted from indoor mixing tanks and the potential operator exposure to carbon dioxide released from a lithium bromide manufacturing operation. This article presents the development, implementation, and results of using the model for small releases from tanks. © 2012 American Institute of Chemical Engineers Process Saf Prog, 2012

A general mathematical programming formulation which also considers safety factors is presented for solving the multi-floor plant layout problem. In the presence of a risk of physical explosion, the safety distance must be considered to generate more reasonable and safe layouts. The proposed method determines detailed multi-floor process plant layouts using mixed integer linear programming (MILP). To consider the safety distance, a consequence analysis is adopted for calculating an equipment physical explosion probit. As the TNT equivalency method is used, more realistic estimations of equipment damage are possible, generating safer plant layouts. The objective function minimizes the layout cost (total plant area, floor construction costs and connection costs) and explosion damage costs for the multi-floor problem. Two illustrative examples are presented to demonstrate the applicability of the proposed method.

Preventing loss of containment of materials and/or energy is a primary goal of industrial Process Safety Management programs. A thorough understanding of the hazards, identification of a complete range of failure events, detailed analysis of the consequences of failure events, and the analysis of process risks accounting for all the safeguards can help significantly in preventing and mitigating loss of containment incidents. In this article, additional details are provided on hazard assessment approaches, consequence analysis of potential events, and risk analysis for minimizing risks. © 2010 American Institute of Chemical Engineers Process Saf Prog, 2010

A HAZOP methodology is presented where a functional plant model assists in a goal oriented decomposition of the plant purpose into the means of achieving the purpose. This approach leads to nodes with simple functions from which the selection of process and deviation variables follow directly. The functional HAZOP methodology lends itself directly for implementation into a computer aided reasoning tool to perform root cause and consequence analysis. Such a tool can facilitate finding causes and/or consequences far away from the site of the deviation. A functional HAZOP assistant is proposed and investigated in a HAZOP study of an industrial scale Indirect Vapor Recompression Distillation pilot Plant (IVaRDiP) at DTU-Chemical and Biochemical Engineering. The study shows that the functional HAZOP methodology provides a very efficient paradigm for facilitating HAZOP studies and for enabling reasoning to reveal potential hazards in safety critical operations.

LNG ships may represent a remarkable risk source, especially when approaching a land terminal, not only due to the possible occurrence of maritime accident, but also since they may represent a suitable target for terrorist attacks. A preliminary risk analysis for LNG ships approaching the Panigaglia terminal is carried out: based on literature data and on the characteristics of the location, a spill originated from a sea accident can be excluded; on the contrary, intentional damages may cause the release of a large amount of LNG, giving rise to a pool fire. Consequence analysis shows that dangerous thermal effects are expected within a radius of 700–1500 m; in the location under exam, the impact on resident population will be negligible, for the most probable attack site, and marginal for an occasionally used anchorage, which should be no longer allowed.

Risk assessments are considered to be an essential tool in ensuring the safety of engineering projects. The benefits of using risks assessments have prompted its acceptance in the safety legislation for a number of industries. The use of quantitative risk assessment for rail transportation of hazardous materials has gained more attention in recent years, because the amount Of the transported hazardous materials is large, and the transportation route often passes through populated areas, such as cities. in this study, the risk for the ammonia transportation by rail in Malaysia was conducted by combining the results from a previous failure frequency analysis and consequence analysis. The assessment results acknowledged the significant effects of train speeds on the overall individual risk. The risk with a tolerable risk limit of 1 X 10(-6) per year increased significantly with more train accidents occurring at increasing speeds. Most of the surrounding populations along the transportation route analyzed are exposed to higher risk levels than the tolerable limit. This risk exposure to the public demonstrates the need for proper planning of moving ammonia through populated areas. (C) 2009 American Institute of Chemical Engineers Process Saf Prog 29: 60-63, 2010

The aim of this paper is to describe a methodology to facilitate a consequence analysis for a pressure wave from a cylindrical vessel burst; however, this methodology can be used for other accident scenarios. The main PROBIT equations to evaluate the direct damage on humans include eardrum rupture, death due to skull fracture, death due to whole body impact, and lung damage. The results are evaluated and the most suitable PROBIT equations are selected. A new methodology is developed to relate the characteristic overpressure–impulse–distance curves for a cylindrical vessel burst, from a previous paper (Gonzalez Ferradas et al., Process Saf Progr 25 (2006), 250-254), with the selected PROBIT equation results. This methodology allows the determination of damage in one step, using explosion energy and distance to the accident's origin. Equations are also developed for using this methodology in a computer program or spread sheet calculations. © 2007 American Institute of Chemical Engineers Process Saf Prog, 2007

In 1992, DeVaull and King used the results of field tests to derive two similarity correlations for non-volatile and volatile liquids, respectively, for the estimation of the rainout fraction xR of flashing liquid releases. These correlations are shown to be flawed, because an incorrect value of the liquid specific heat of CFC-11 has been used to derive them. The field test data corrected in 1994 with the UDM model are used to derive a new correlation valid for non-volatile as well as volatile liquids. The new correlation is xR=0.6(1–3xH) where xH is the isenthalpic flash fraction. Use of the new correlation with the public domain consequence analysis code ALOHA is outlined.

The field of oil spill cost modelling is not as well explored as desirable. Generally speaking, the existing models have either low accuracy, in that their predictions are far from the real cost, or low applicability, in that they are only valid under very specific conditions; such as in one particular country. This work strives to construct a model that is functional in a global scope and still possess a high level of accuracy. The resulting attempt is in manyways superior to the publicly available competitors, not only because of its predictive capacity but also because the model is quick to use, and its input variables should be readily available to any informed user. The model is more accurate comparing with similar available models. However, further study is needed to modify it to obtain more realistic results. © 2008 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

This paper aims at presenting a methodology to perform consequence analysis produced by pressure waves from spherical vessel burst. To carry out this operation characteristic curves are used. These characteristic curves for spherical vessel burst were presented in a previous paper [Gonzalez Ferradas, E., Diaz Alonso, F., Sanchez Perez, J.F., Minana Aznar, A., Ruiz Gimeno, J. and Martinez Alonso, J., 2006. Characteristic overpressure–impulse–distance curves for vessel burst, Process Safety Progress, 25(3): 250–254]. They allow the overpressure and impulse to be determined at each distance from the vessel. When combined with damage criteria (such as those shown by the PROBIT equations), the characteristic curves allow consequence analysis for this kind of explosions to be carried out, as the damage is shown in the same diagram as the overpressure, impulse and distance. In this paper the main PROBIT equations to evaluate damage to humans from pressure waves (which include eardrum rupture, death due to skull fracture, death due to whole body impact and lung damage) are evaluated and the most suitable PROBIT equations are selected. Diagrams are presented and equations are also developed for using this methodology in a computer program or spread sheet calculations.

In this research, a simple package called CPR 2.0 software was developed according to the algorithm suggested by AIChE/CCPS and implemented using Compaq Visual Fortran (CVF 6.6) programming language and METFOR 3.0 Fortran 90/95 Library. This multipurpose software includes nine sets of programs that can be used in combination or separately to calculate physical, effect, and vulnerability consequences; their results can also be easily processed into different tables and figures. A set of three-dimensional (3D) gas release contours with different concentration isosurfaces and transient dispersion states floating above a local map can be easily observed from different angles in order to facilitate emergency response planning and educational training. The software has been benchmarked with CHEMS-PLUS software via a methane release case and the result from the two packages is compared and analyzed.

In a previous paper, the characteristic overpressure–impulse–distance curves for the detonation of explosive substances were presented. They allow the overpressure and impulse to be determined at each distance from the detonation. When combined with damage criteria (such as those shown by the Probit equations), the characteristic curves allow consequence analysis for this kind of explosion to be carried out in only one step, as the damage is shown in the same diagram as the overpressure, impulse and distance. In this paper, diagrams and equations are presented to determine the damage to humans (eardrum rupture, death due to displacement and skull fracture, death due to displacement and whole body impact, and death due to lung damage or lung haemorrhage).

The process area of an offshore oil and gas platform is very compact with a high degree of congestion and confinement due to space limitations and environmental conditions. Although there are safety systems installed on the platforms, the process area is never completely safe. Among the loss producing events, fires and explosions are the most frequently reported process related accidents. They have potential to cause serious injury to personnel, major damage to equipment and structure, and disruption of operations. It is therefore necessary to perform a fire and explosion hazard analysis as a basis for the implementation of appropriate mitigation measures and emergency response plans to protect personnel. In this paper, we reviewed the existing consequence models, such as source models, dispersion models, ignition models, fire and explosion models, and selected the ones most suitable for offshore conditions. These models were then used to perform a consequence assessment for an offshore platform by simulating four different scenarios. Two main revisions were incorporated: (1) a grid-based approach was adopted to enable better consequence/impact modelling and analysis of radiation and blast overpressures, and (2) an enhanced onsite ignition model was integrated in the consequence assessment process to obtain better results.

Although the best time for implementation of inherently safer design alternatives is during early process development and plant design, there are often opportunities to modify an existing plant to significantly enhance inherent safety. We will describe a modification to a bromine raw material handling facility, replacing an existing bulk storage tank with cylinders. Incident consequence analysis and quantitative risk analysis were used to understand the relative inherent safety characteristics of the design options. © 2005 American Institute of Chemical Engineers Process Saf Prog, 2006

The applications of chlorine have been broadly used in many industrial products, such as bleaching agents, synthetic rubbers, plastics, disinfectants, iron chlorides, fire refractory materials, insecticides, and anti-freezers, etc. According to the Taiwan Environmental Protection Administration (TEPA), more than 30 thousand tons were used in the year 2000. In addition, there were more than 12 reported incidents from 2000 to 2003—mostly on using chlorine as disinfectants (five) and as process agents (four). This study investigated 15 chlorine operation plants in central Taiwan. These chlorine usages included bleaching agents, disinfectants, iron chloride, synthesizing rubber plastics, and others. Thirteen plants were located in the industrial parks and two were in or near residential zones. The consequence analysis were used three different methods to analyze the worst-case scenarios (WCSs) and alternative release case scenarios (ACSs) in order to compare impact zones for applying various active and passive mitigation systems, such as confined space, scrubber, water-spray, and so no. For two plants in or near residential zones, multi-layers mitigation systems and operation limits should be implemented in order to enforce more stringent protection measures. However, there was no specific regulation for chlorine plants operated at different locations, such as industrial parks or residential zones. In order to reduce chemical accidents and their impacts on public safety, our results suggest that source mitigation/management and warning systems should be adopted simultaneously.

Industrial licensing activities require safety and environmental studies to enhance safety and environmental protection especially as applied to pipelines. After World War II, industrial activities increased and accident risk analyses are now routinely made to reduce hazards. Most common accidents such as toxic emissions, fires, and explosions must be avoided. The risk analysis technique is used to prevent these undesired events. In this paper, accident scenarios and consequence analysis are conducted to investigate events and consequences concerning a natural gas (NG) pipeline. We found that fatalities can occur within a 260-m radius if there is a gas pipeline collapse. At distances < 30 m, injuries can occur as a result of thermal radiation exposure to the jet fire. Secondary effects from gas explosions will also occur within these distances. These results demonstrate the importance of (1) routing pipelines away from populated areas and (2) preventive maintenance to prevent leaks. © 2004 American Institute of Chemical Engineers Process Saf Prog, 2004

This study deals with the consequence analysis of an accidental release of chlorine from a storage tank in a chlor-alkali plant. Chlorine is a liquefied gas and is stored in tanks for various uses like the production of textiles, paper products, and so forth. Chlorine is highly toxic and if released accidentally has the potential to kill or injure people in the vicinity of the storage tank. Calculations are used to determine the discharge rate of chlorine in liquid phase, liquid–gas phase, and gas phase. Subsequently, dispersion calculations are used to determine the downwind concentrations in the vicinity of the tank. The probit equation is used to estimate fatalities for the various accident scenarios. These results are used to develop improvement needs and an emergency response plan. © 2012 American Institute of Chemical Engineers Process Saf Prog, 2012

Forecasting the behaviour of a flammable or toxic cloud is a critical challenge in quantitative risk analysis. Recent literature shows that empirical and integral models are unable to model complex dispersion scenarios, like those occurring in semi-confined spaces or with the presence of physical barriers. Although CFD simulators are promising tools in this regard, they still need to be fully validated with comprehensive datasets coming from experimental campaigns designed ad-hoc. In this paper, we present an experimental campaign carried out by a joint venture between University of Sao Paulo and Universitat Politecnica de Catalunya to investigate CFD tools performance when used to analyse clouds dispersion. The experiments consisted on propane cloud dispersion field tests (unobstructed and with the presence of a fence obstructing the flow) of releases up to 0.5 kg s(-1) of 40s of duration in a discharge area of 700 m(2). We provide a full 1-s averaged propane concentration evolution dataset of two experiments, extracted from 29 points located at different positions within the cloud, with which we have tested FLACS (R) CFD-software performance. FLACS reproduces successfully the presence of complex geometry, showing realistic concentration decreases due to cloud dispersion obstruction by the existence of a fence. However, simulated clouds have not represented the whole complex accumulation dynamics due to wind variation. (C) 2015 Elsevier Ltd. All rights reserved.

The use of a new computer-automated tool TORAP (TOol for Rapid risk Assessment in Petroleum refinery and petrochemical industries) is demonstrated through a rapid and quantitative risk assessment of a typical petroleum refinery. The package has been applied for an appraisal of the risks of accidents (fires, explosions, toxic release) posed by different units of the refinery, and to identify steps to prevent/manage accidents. The studies reveal that TORAP enables a user to quickly focus on the accidents likely to occur, and enables forecasting the nature and impacts of such accidents. This information is directly utilisable in identifying “soft” spots and in taking appropriate remedial measures to prevent or control accidents. The special attributes of TORAP are: (a) a wide range of applications—achieved by incorporating models capable of handling all types of industrial fires and explosions, (b) sophistication—brought about by including state-of-the-art models developed by these authors and others, (c) user-friendliness—achieved by incorporating on-line help, graphics, carefully formatted output, and, above all, an automatic module with which even a lay user can conduct risk assessment. The entire package, especially its automatic module, is supported by an extensive knowledge-base built into the software.

EPA's Risk Management Program regulation, promulgated in June 1996 as 40 CFR Part 68 requires subject industries to submit Risk Management Plans by June 1999. This plan requires hazard assessment of the operations of a facility using worst case scenarios and alternative releases. EPA has provided an Off-site Consequence Analysis (OCA) guidance to help facilities in their hazard assessment. OxyChem will be significantly impacted by the RMP rule. This paper outlines OxyChem's general experience and its strategy in planning to comply with this rule. OxyChem's approach in the development of the scenarios required by the rule is described in this paper. Limitations involved in the use of EPA's look-up tables or a single modeling solution for conducting all of the OCA are discussed. A three tiered OCA approach is presented as a possible alternative.

The Brazoria County Petrochemical Council, 13 companies that are working together to enhance relations between industry and the community, united in a joint effort at complying with the EPA's Risk Management Program. One of the significant issues the group had to address was the need to develop meaningful hazard assessment for presentation to the public. The EPA's “Table Look-Up Approach” found in the Offsite Consequence Analysis Guidance document is certainly a good tool; however, the built-in conservatism results in over-estimates of potential hazard areas. Much more meaningful results are shown to be obtained using one of the hazard release models. The value of using a credible scenario with realistic meteorological data is demonstrated through the consistently smaller areas predicted by the PHAST Model for planning purposes. Realistic scenarios/failure modes and realistic model parameters are important so that the risk to the public is not overstated. Proprietary models such as PHAST are invaluable in providing more meaningful consequences for planning purposes.

Natech accidents at industrial plants are an emerging risk with possibly serious consequences. For the mitigation of natech risk, authorities need to identify natech prone areas in a systematic manner. In order to facilitate probabilistic natech risk mapping, a unified methodology was developed that is based on the estimation of on-site natural hazard parameters, determination of damage probabilities of plant units, and assessment of probability and severity of possibly triggered natech events. The methodology was implemented as an on-line, extensible risk assessment and mapping software framework called RAPID-N, which allows rapid local and regional natech risk assessment and mapping with minimal data input. RAPID-N features an innovative data estimation framework to complete missing input data, such as on-site natural hazard parameters and plant unit characteristics. The framework is also used for damage assessment and natech consequence analysis, and allows easy modification of input parameters, dynamic generation of consequence models according to data availability, and extension of models by adding new equations or substituting existing ones with alternatives. Results are presented as summary reports and interactive risk maps, which can be used for land-use and emergency planning purposes by using scenario hazards, or for rapid natech consequence assessment following actual disasters. As proof of concept, the framework provides a custom implementation of the U.S. EPA's RMP Guidance for Offsite Consequence Analysis methodology to perform natech consequence analysis and includes comprehensive data for earthquakes. It is readily extendible to other natural hazards and more comprehensive risk assessment methods. (C) 2013 Elsevier Ltd. All rights reserved.

As well known, risk is a combination of probability and consequences of an accident. In analyzing the consequence of accidental hydrocarbon fires and the potential for domino effects, the evaluation of the flame extent and temperature are of the utmost importance. Since the primary effects of pool fires are connected to thermal radiation and issues of interplant/tank spacing employees’ safety zones, firewall specifications are to be addressed on the basis of a proper consequence analysis. By means of real scale experimental tests it was verified that both the thermal power and the flame temperature, Tf, increase as the pool area increases, up to reach maximum values in connection with a “critical pool dimension”. Dealing with pool areas higher than the critical one, experimental results, performed by different researchers at different scales, show a decrease of Tf. An in-depth analysis of the different concurring phenomena connected to a pool fire development allowed identifying the limiting step controlling the flame temperature. In fact, the trend of Tf is mainly determined by the increasing difficulty of oxygen diffusion within the internal bulk of gaseous hydrocarbons. In this article, we propose a novel pool fire modelling approach based on the simplified physical phenomena occurring in a circular turbulent diffusion fire and suitable to provide a theoretical insight into the above-mentioned experimental trends and to obtain the maximum values of the flame temperature and of the thermal power. The geometry of the pool is dictated by the surroundings (i.e., diking) and the analytical models here presented were successfully applied to the common situation of circular pools. However, it must be remarked that the developed model, matching fairly well experimental data for different hydrocarbons, can be applied in modelling similar scenarios characterized by different geometric or environmental conditions (e.g. road and rail tunnel fires).

Thermally initiated cascade effects can have devastating results for large petroleum refineries or chemical installations on industrial estates. Adjacent plant installations are involved and the overall damage is potentially several times greater than for individual events. In spite of its great practical importance, consequence analysis of cascade effects has received little attention due to the mechanistic complexities involved. This paper highlights the possible theoretical approaches to assess the consequences of cascade effects. The importance of modelling and linking the time variant thermal interchange between installations, failure of vessels under thermal and other stresses and the subsequent fracture fragmentation and impact phenomena are stressed.

Risk assessment of a chemical process plant requires the application of a variety of consequence models in order to estimate the potential physical effects of accidental releases. The types of models required vary depending upon the substance under consideration and the circumstances of a release. The objective of this study was the development and application of a system based upon ‘fuzzy logic’, for the selection of a computer model to be used in consequence analysis in specific situations where only certain types of consequence models can be used. The collection of data for modelling purposes from different kinds of computer model and application of fuzzy methods were also important aims of the study.