Small-scale fire performance assessment of intumescent coatings on metal tubes containing ammonium nitrate. A stepping-stone towards their application as a fire safety measure on road transportation tanks?

Ammonium nitrate is used in vast amounts globally, first and foremost as a component of fertilizers and explosive formulations. This usage necessitates its transportation which, as for most hazardous materials, involves certain risks. For oxidizing materials such as ammonium nitrate, the ultimate consequence of road transportation incidents is usually considered to be fire followed by explosion. Even though the probability in general is low, substantial reduction in its risk is a great gain for public safety. Thus, identifying novel and improving current safety measures for risk reduction, is an important aspect in the field of hazardous materials. Herein, a series of experiments are reported, which demonstrate the fire protection performance of two state-of-the-art intumescent passive fire protection materials on small-scale metal test tubes containing ammonium nitrate. Albeit being initial experiments on laboratory-scale, these results provide a promising starting point for further investigations on the potential of these materials for the fire protection of ammonium nitrate when carried in metal tanks. At its best, a prominent protection of ammonium nitrate from heat exposure was observed, as the temperature was kept well below its boiling point for more than 2.5 h. Successively, it resulted in a complete recovery of the sample material. This was in large contrast to the observed results for the unprotected test tubes, which led to complete decomposition of the sample after 11 min.     

A review of hazards associated with primary lithium and lithium-ion batteries

Primary lithium batteries contain hazardous materials such as lithium metal and flammable solvents, which can lead to exothermic activity and runaway reactions above a defined temperature. Lithium-ion batteries operating outside the safe envelope can also lead to formation of lithium metal and thermal runaway. Despite protection by battery safety mechanisms, fires originating from primary lithium and lithium-ion batteries are a relatively frequent occurrence.This paper reviews the hazards associated with primary lithium and lithium-ion cells, with an emphasis on the role played by chemistry at individual cell level. Safety mechanisms to prevent the occurrence and limit the consequences of incidents are reviewed, together with safety tests to monitor compliance with battery safety regulations and standards. Incident information from news accounts and open literature sources are reviewed to extract causal information.It is concluded that the potential severity of incidents during storage, transport and recycling of waste batteries can be significantly higher than in end-use applications. Safe storage, packaging and labelling practices, as well as communication among the parties involved, are essential to ensure safety across the battery lifecycle. It is recommended that a database of lithium battery incidents would be valuable to improve the evidence base for informing accident prevention measures.     

Analysis of laboratory incident database

With the growth of academic institutions, the number of labs handling hazardous chemicals has increased. Although the chemicals used in academic institutions are well-known, the dosage, usage, and management of these chemicals pose significant threat to researchers at all levels. As a step towards incident prevention, a laboratory incident database was developed to record incidents at universities and secondary schools. The data consisted of 128 entries occurring during the years 2012–2015. Incidents were classified by institution type, hazard type, consequences, substance type, body parts injured and direct causes. Of 128 incidents, 65% of the incidents were taking place in universities. Chemical spills were observed to be the most recurrent hazard type contributing to 45% of the incidents following by explosions (23%) and fires (21%). The consequence which most frequently occurred in incidents was personal injury and hazmat response contributing to 22% each. It was observed that in 41% of the incidents, the body parts injured in the incident was not known or reported. Of the total 128 incidents, about 50 incidents occurred due to improper storage and handling.     

Determination of the critical flammability ratio (CFR) of refrigerant blends

In order to avert hydrocarbons, (HCs) and some hydrofluorocarbons, (HFCs) inherent risk of fire, combinations with inert refrigerant fluids have already been investigated and accepted as the preferred approach for the replacement of hydrochlorofluorocarbons (HCFCs). Indeed, many of the HFCs offer characteristics (in particular, thermodynamic properties, performance, compatibility with existing equipment, moderate toxicity and relatively low cost) similar to the those of HCFCs. However, the mixing or use of a multiple-component blend may introduce a potential fractionation behavior, which cannot be disregarded due to its influence on the blend flammability characteristics.Assessing the evolution of the Concentration Limits of Flammability of a blend formulation as it is depleted is therefore essential and leads to the definition of the Flammability Ratio (FR) as the ratio of the concentrations of the flammable to nonflammable blend components. Only one FR value corresponds to one particular blend formulation. As flammability tests on different blend formulations (different FR values) are performed, one can define the threshold between flammable and nonflammable blend formulations. Per definition, the Critical Flammability Ratio (CFR) corresponds to the FR threshold between flammable and nonflammable blend formulations. This value sets a decisive baseline for fire risk assessment of refrigerant blends subject to fractionation behavior.This paper presents several methods to evaluate FRs and ultimately CFRs of a blend of multiple flammable and nonflammable components. As the FR value is varied until flammable and nonflammable blend formulations are found within a predetermined accuracy, new blend formulations are calculated and tested for combustibility. Relationships and computations from an initial blend formulation to another are therefore provided herein. Three different sets of assumptions to solve the required set of (n) equations system (for n components in the blend) are presented. Convergence, physical interpretation, extents and limitations of each method are included.     

A posteriori hazard analysis and feedback information of an accidental event in the grains storage of an agrochemical product

The present study concerns a hazardous event which occurred in an industrial storage tank of a ground insecticide. A preliminary post-accident approach of the hazard evaluation is performed. The rapid report of the presence of an unstable functional group in the active product and of its potential thermal instability (CHETAH indices) has led to complete this examination by an experimental study of thermal analysis using isotherm exposition measurement (DTA) or with temperature programming by differential scanning calorimetry (DSC) and oxidability tests (BAM). The apparent kinetics of decomposition of the active matter of the ground insecticide has been represented by a global Arrhenius law.

A model designed for the simulation of heterogeneous thermal runaways based on the numerical solution of the transient mass and energy balances has been further applied to define the critical conditions of the storage and simulate its behavior.

The results obtained during this analysis with the experienced feedback allowed us on one side to explain the hazardous event and especially on the other side to modify the operating protocol of the conditions of formulation of the active matter on the inert mineral support.     

基于前导事件和贝叶斯网络的储罐溢油动态风险评价

部分高风险危化品企业搬迁改造困难重重,为控制风险、保护周围人民生命和财产安全,有必要建立动态风险评价系统,对事故发生概率进行监控和预测。采用贝叶斯网络对事故发生概率进行定量分析。先在利用蝴蝶结模型辨识事故原因和后果的基础上,将其转化为贝叶斯网络模型;再导入"前导事件"信息和先验概率推导后验事故发生概率,量化分析事故发生随时间的变化概率;最后,以储罐溢流场景为例进行动态风险计算,结果表明,随化工装置生产时间和"前导事件"增长,元件失效概率和事故风险呈显著增长趋势。因此建议企业应重视"前导事件"并采取措施减少"前导事件",如优化检维修方案、及时更换关键部件、进行全面的事故调查等。     

Thermal risk analysis of cumene hydroperoxide in the presence of alkaline catalysts

Many studies have been performed to clarify the basic thermal runaway hazards and kinetics of cumene hydroperoxide (CHP) decomposition. However, materials that are incompatible with CHP have not been clearly identified. Alkaline solutions have been used as a catalyst to form dimethylphenyl carbinol (DMPC) and dicumyl peroxide (DCPO); however, these solutions also affect the reaction and storage temperature of CHP. In this study, thermal calorimeters, differential scanning calorimetry (DSC) and vent sizing package 2 (VSP2), were used to compare the effects of various bases on the decomposition of CHP in cumene. Specifically, the exothermic onset temperature, change in pressure over time, self-heating rate and heat of decomposition were evaluated. Moreover, to appraise the degree of hazard associated with the use of CHP, the compatibility of CHP with various substances was analyzed, and a risk matrix for thermal runaway reactions was obtained. The results of the present study could be used to design safety procedures for the production of CHP and its derivatives.     

A case control study of falling incidents among the hospitalized elderly

Falling incidents among the hospitalized elderly were investigated using a case/control methodology to identify high-risk individuals. The medical records of all patients who had a reported fall (N = 173) in 1978 in one geriatric facility were compared with the records of a random sample of patients without a reported fall (N = 339). The significant risk factors were male sex, urinary incontinence within 48 hours prior to the fall, and psychoactive medication 12 hours prior to the fall. It was concluded that some patients may have a greater tendency to fall than others and suggestions for exploring future means of prevention are presented.     

Risk management of cost consequences in natural gas transmission and distribution infrastructures

A critical aspect of risk management in energy systems is minimizing pipeline incidents that can potentially affect life, property and economic well-being. Risk measures and scenarios are developed in this paper in order to better understand how consequences of pipeline failures are linked to causes and other incident characteristics. An important risk measure for decision-makers in this field is the association between incident cause and cost consequences. Data from the Office of Pipeline Safety (OPS) on natural gas transmission and distribution pipeline incidents are used to analyze the association between various characteristics of the incidents and product loss cost and property damage cost. The data for natural gas transmission incidents are for the period 2002 through May 2009 and include 959 incidents. In the case of natural gas distribution incidents the data include 823 incidents that took place during the period 2004 through May 2009. A two-step approach is used in the statistical analyses to model the consequences and the costs associated with pipeline incidents. In the first step the probability that there is a nonzero consequence associated with an incident is estimated as a function of the characteristics of the incident. In the second step the magnitudes of the consequence measures, given that there is a nonzero outcome, are evaluated as a function of the characteristics of the incidents. It is found that the important characteristics of an incident for risk management can be quite different depending on whether the incident involves a transmission or distribution pipeline, and the type of cost consequence being modeled. The application of this methodology could allow decision-makers in the energy industry to construct scenarios to gain a better understanding of how cost consequence measures vary depending on factors such as incident cause and incident type.     

大数据发展的信息安全风险防御探析

大数据的发展及广泛应用加大了信息化系统及数据的脆弱性,信息安全风险向系统化、复杂化方向发展。在搜集、整理国内外相关研究成果基础上,系统辨识数据采集、数据传输、数据存储、数据分析4个大数据核心环节的信息安全风险,围绕“风险辨识、脆弱性降低、风险沟通、强化风险管理”的风险治理流程,以防范与化解信息安全风险为目标,提出大数据发展的信息安全防御策略。研究结果表明:大数据全生命周期是信息安全风险辨识的起点,强化大数据发展的信息安全风险防御,需要在风险辨识基础上,积极推进预防准备、风险沟通、信息安全事件处置及恢复总结。     

Causative factors for vapour cloud explosions determined from past-accident analysis

Past-accident analysis shows that most dangerous incidents are related to process operations. Often these operations are carried out under high pressures and/or high temperatures. The consequences, therefore, are significant. A scientific analysis of past accidents which led to vapour cloud explosion has been performed. The analysis has provided vital information for most probable accident scenarios for a new situation. Factors such as chemical characteristics, its release mode, time etc. show trends and relationships for the occurrence of vapour cloud explosions.     

A new multiple-risk map approach to solve process plant layout considering safety and economic aspects

Mathematical models used to optimize the process plant layout (PPL) with risk reduction have four primary objectives, which are related to the minimization of land, pumping (pipe system), protection system devices, and risk costs. Moreover, these models are of two types: continuous plane models (CPM) and grid-based models (GBM); however, the nonconvexity of the CPM models makes difficult to achieve the global optimum, because it is formulated as Mixed-Integer Nonlinear Programming (MINLP). Thus, the risk map approach has been implemented with the grid-based models to solve problems of process plant layout focused on finding the best possible solution. However, these risk map formulations present important limitations, mainly related with the use of protection devices and the occupied area. Therefore, a new GBM-MILP formulation is proposed to optimize the selection of protection devices and minimize the occupied area. The risk is reduced through the investment on safety devices instead of considering the increase of separation distances. The proposed model was used to solve the layout problem of an ethylene oxide process, and the results was compared with a process layout reported in the literature. The results show that the model can provide the best possible solution; however, the time spent in the calculation is considerably greater than that reported for continuous plane models. Finally, the model can be used by decision-makers to evaluate different layout options for several explosion scenarios, during the early stages of the plant design.     

Work environment risk factors for injuries in wood processing

Problem

The reported injury rate for wood product manufacturing in Maine, 1987-2004, was almost twice the state-wide average for all jobs. Method: A case-control study was conducted in wood processing plants to determine preventable risk factors for injury. A total of 157 cases with injuries reported to workers' compensation and 251 controls were interviewed. Results: In multivariable analyses, variables associated with injury risk were high physical workload, machine-paced work or inability to take a break, lack of training, absence of a lockout/tagout program, low seniority, and male gender. Different subsets of these variables were significant when acute incidents and overexertions were analyzed separately and when all injuries were stratified by industry sub-sector. Impact on industry: Generalizability may be limited somewhat by non-representative participation of workplaces and individuals. Nevertheless, these findings provide evidence that many workplace injuries occurring in wood processing could be prevented by application of ergonomics principles and improved work organization.     

Optimizing the design of storage facilities through the application of ISD and QRA

Four strategies can be used to achieve safety in chemical processes: inherent, passive, active and procedural. However, the strategy that offers the best results is the inherent safety approach, especially if it is applied during the initial stages of a project. Inherently Safer Design (ISD) permanently eliminates or reduces hazards, and thus avoids or diminishes the consequences of incidents. ISD can be applied using four strategies: substitution, minimization, moderation and simplification. In this paper, we propose a methodology that combines ISD strategies with Quantitative Risk Assessment (QRA) to optimize the design of storage installations. As 17% of major accidents in the chemical industry occur during the storage process and cause significant losses, it is essential to improve safety in such installations. The proposed method applies QRA to estimate the risk associated with a specific design. The design can then be compared to others to determine which is inherently safer. The risk analysis may incorporate complex phenomena such as the domino effect and possible impacts on vulnerable material and human elements. The methodology was applied to the San Juanico tragedy that occurred in Mexico in 1984.     

Dynamic risk assessment using failure assessment and Bayesian theory

To ensure the safety of a process system, engineers use different methods to identify the potential hazards that may cause severe consequences. One of the most popular methods used is quantitative risk assessment (QRA) which quantifies the risk associated with a particular process activity. One of QRA's major disadvantages is its inability to update risk during the life of a process. As the process operates, abnormal events will result in incidents and near misses. These events are often called accident precursors. A conventional QRA process is unable to use the accident precursor information to revise the risk profile. To overcome this, a methodology has been proposed based on the work of Meel and Seider (2006). Similar to Meel and Seider (2006) work, this methodology uses Bayesian theory to update the likelihood of the event occurrence and also failure probability of the safety system. In this paper the proposed methodology is outlined and its application is demonstrated using a simple case study. First, potential accident scenarios are identified and represented in terms of an event tree, next, using the event tree and available failure data end-state probabilities are estimated. Subsequently, using the available accident precursor data, safety system failure likelihood and event tree end-state probabilities are revised. The methodology has been simulated using deterministic (point value) as well as probabilistic approach. This Methodology is applied to a case study demonstrating a storage tank containing highly hazardous chemicals. The comparison between conventional QRA and the results from dynamic failure assessment approach shows the significant deviation in system failure frequency throughout the life time of the process unit.     

Overfill protective systems – Complex problem,simple solution

Overfills have resulted in significant process safety incidents. Longford (Australia, 1998), Texas City (United States, 2005), and Buncefield (United Kingdom, 2005) can be traced to loss of level control leading to high level and ultimately to loss of containment. A tower at Longford and a fractionating column at Texas City were overfilled, allowing liquid to pass to downstream equipment that was not designed to receive it. The Buncefield incident occurred when a terminal tank was overfilled releasing hydrocarbons through its conservation vents.The causes of overfill are easy to identify; however, the risk analysis is complicated by the combination of manual and automated actions often necessary to control level and to respond to abnormal level events. This paper provides a brief summary of the Longford, Texas City, and Buncefield incidents from an overfill perspective and highlights 5 common factors that contributed to making these incidents possible. Fortunately, while overfill can be a complex problem, the risk reduction strategy is surprisingly simple.     

A violent,episodic vapour cloud explosion assessment: Deflagration-to-detonation transition

A large vapour cloud explosion (VCE) followed by a fire is one of the most dangerous and high consequence events that can occur in petrochemical facilities. The current process of safety practice in the industry in VCE assessment is to assume that all VCEs are deflagration. This assumption has been considered for nearly three decades. In recent years, major fire and VCE incidents in fuel storage depots gained considerable attention in extreme high explosion overpressure due to the transition from Deflagration to Detonation (DDT). Though the possibility of DDTs is lower than deflagrations, they have been identified in some of the most recent large-scale VCE incidents, including Buncefield (UK), 2005, San Juan explosion (US), 2009, and IOCL Jaipur (India), 2009 event. Such an incident established the need to understand not only VCE but also the importance of avoiding the escalation of minor incidents into much more devastating consequences.Despite decades of research, understanding of the fundamental physical mechanisms and governing factors of deflagration-to detonation transition (DDT) transition remains mostly elusive. An extreme multi-scale, multi-physics nature of this process uncertainly makes DDT one of the “Grand Challenge” problems of typical physics, and any significant developments toward its assured insistence would require revolutionary step forward in experiments, theory, and numerical modelling. Under certain circumstances, nevertheless, it is possible for DDT to occur, and this can be followed by a propagating detonation that quickly consumes the remaining detonable cloud. In a detonable cloud, a detonation creates the worst accident that can happen. Because detonation overpressures are much higher than those in a deflagration and continue through the entire detonable cloud, the damage from a DDT event is more severe. The consideration of detonation in hazard and risk assessment would identify new escalation potentials and recognize critical buildings impacted. This knowledge will allow more effective management of this hazard.The main conclusion from this paper is that detonations did occur in Jaipur accident at least part of the VCE accidents. The vapour cloud explosion could not have been caused by a deflagration alone, given the widespread occurrence of high overpressures and directional indicators in open uncongested areas containing the cloud. Additionally, the major incident has left many safety issues behind, which must be repeatedly addressed. It reveals that adequate safety measures were either underestimated or not accounted for seriously. This article highlights the aftermath of the IOCL Jaipur incident and addresses challenges put forward by it.