Fire and explosion hazard analysis during surface transport of liquefied petroleum gas (LPG): A case study of LPG truck tanker accident in Kannur,Kerala, India

This paper presents an analysis and simulation of an accident involving a liquefied petroleum gas (LPG) truck tanker in Kannur, Kerala, India. During the accident, a truck tanker hit a divider and overturned. A crack in the bottom pipe caused leakage of LPG for about 20 min forming a large vapor cloud, which got ignited, creating a fireball and a boiling liquid expanding vapor explosion (BLEVE) situation in the LPG tank with subsequent fire and explosion. Many fatalities and injuries were reported along with burning of trees, houses, shops, vehicles, etc. In the present study, ALOHA (Area Locations of Hazardous Atmospheres) and PHAST (Process Hazard Analysis Software Tool) software have been used to model and simulate the accident scenario. Modeling and simulation results of the fireball, jet flame radiation and explosion overpressure agree well with the actual loss reported from the site. The effects of the fireball scenario were more significant in comparison to that of the jet fire scenario.     

Dynamic Inherently Safer Modifications: Metric development and its validation for fire and explosion prevention

Of the numerous inherent safety assessment tools, a dynamic metric capable of investigating and incorporating the temporal risk evolution when conducting Inherently Safer Modifications (ISMs) is yet to be established. To this end, this work developed a Dynamic Inherent Safety Metric (DISM) and validated its functionality and viability through a case study. Firstly, the Information-Flow-based Accident-causing Model (IFAM) was adapted to construct the topology of Bayesian Networks (BN). Then, Bayesian deductive reasoning was executed to do crucial risk identification by ranking posterior probabilities. Finally, risk-based ISMs were performed to address the relatively contributing risk factors. The case study results show that the fire and explosion risk decreased by approximately a third after implementing ISMs, thus demonstrating that the modified processing scenario could be inherently safer than the original processing scenario. The newly developed inherent safety metric (i.e., DISM) can assist in temporal risk identification and assessment, and it is expected to function as a novel assessment tool for measuring and comparing the inherent safeness before and after implementing ISMs with simultaneous considerations on the time-varying risk factors.     

初始温度对湿法成型硫磺燃烧爆炸特性影响的试验研究

为了研究初始温度变化对湿法成型硫磺粉尘燃烧爆炸特性的影响,通过对初始温度分别为35℃、 45℃、 55℃、 65℃、 75℃的硫磺粉尘试样进行测试,发现随着初始温度的上升硫磺粉尘的粉尘云最低着火温度,粉尘云最小点火能逐渐降低;随着初始温度的上升硫磺粉尘的爆炸下限和粉尘层最低着火温度不发生变化。随着温度的升高,硫磺粉尘的燃烧爆炸危险性增加,因此在气温较高的夏秋季节要提高硫磺粉尘燃爆的防护等级。     

Process loss prevention of petrochemical process: A case study of the flashing accident of the storage tank on acrylonitrile-butadiene-styrene powder in Taiwan

Qualitative analysis, process hazard analysis, thermal evaluation, and fault tree analysis were applied to a flashing accident involving a storage tank that contained acrylonitrile-butadiene-styrene (ABS) powder in Taiwan. The accident was caused by combustible powder attached to the inner wall of the tank reaching a high temperature and then melting. Thereafter, the molten powder became glue-like and dropped onto the ABS powder, burning at the tank bottom, causing decomposition of the styrene and butadiene derivatives as well as other combustible gases. The high concentration of combustible powder and low ignition temperature triggered the powder, initiating a dust explosion. Finally, we analyzed the findings of each method and examined the properties of ABS powder, realizing that the root cause of the accident included an insufficient understanding of the characteristics of ABS and the failure to comply with the management procedures of hot work. Recommendations and countermeasures were proposed that could proactively ameliorate process safety.     

Selection of failure frequency and its impact on risk assessment – A case study from plot plan optimisation

Facility Siting is an important phase of project development. A critical stage is plot plan optimisation, where significant potential hazards are eliminated due to equipment spacing. In addition to ensuring appropriate compliance with minimum spacing requirements, occupied building studies to achieve compliance with the requirements of API 752 and API 753 could also be undertaken to optimise safety outcomes. The studies are done in three stages, where the first stage is hazard identification, second stage is consequence assessment and the third stage is risk assessment. Third stage assessments are only carried, if the consequence based siting recommendations are not practical to implement.This paper presents the challenges in estimating risk due to process hazards with a focus on selecting right event likelihood data. A comparison is presented on the variation in predicted risk levels based on equipment failure rates and leak frequencies.Case study of a plot plan optimisation study is undertaken with DNVGL Phast Risk and the variation in risk levels up to two orders of magnitude are recorded. Challenges such as adaption of data for local conditions, consistent definitions of failure, sample size of data, applicability of data play a significant role in identifying and correctly quantifying the risk levels. Such challenges and its impact on risk quantification are presented in this paper as well as its impact on facility siting.     

Method to map human and infrastructure vulnerability using CNN land cover: Case study of floating tank explosion at petrochemical plants of LaemChabang,Thailand

Industrial storage tanks, used to store flammable materials in the petrochemical industry, can induce potential fire and explosion under specific conditions. Therefore, it is necessary to map the population and environment vulnerability, and, to develop procedures for emergency responses in order to reduce potential casualties. In order to achieve this, Convolutional Neural Networks (CNN) are used in this study using 6 classes: floating tank, forest, house, road, wasteland and water. Datasets are built for a total of approximately 1.4 million tiles with a resolution of 0.33m/pixel and their size are optimized in function of the class. The 6 associated CNN models are built and optimized to classify each class. The validation of the models shows that, with the exception of road and wasteland where the precision is only 73% and 89% respectively, the other 4 classes have a value higher than 95%. Post-processing is performed on each prediction before aggregating these results to obtain the land cover. For the floating tank class, a 5 step post-processing is used based on a Density-Based Spatial Clustering of Applications with Noise algorithm (DBCAN) after which blast simulation is applied and effects on people, buildings and trees are obtained through 4 steps. Finally, the petrochemical site of LaemChabang in Thailand is used as study case. Except for the road class that is difficult to detect, land cover is well performed. Human casualties and surface of damaged buildings are finally estimated demonstrating the usefulness of the tool to be used for the emergency planning of industrial disasters.     

Prevention and mitigation of injuries and damages arising from the activity of subliminal enterprises: A case study in Slovakia

The paper focuses on risk sources under no legislative pressure in the field of prevention of major accidents. Despite this, they can represent significant sources of risk of accidents.The aim of the paper is to present the results of the risk assessment associated with the operation of enterprises not regulated by the SEVESO III Directive (the so-called subliminal enterprises), to provide information on possible operational problems and to verify the applicability of recognized risk analysis methods for these specific sources of risk. Last but not least, its purpose is to point out that subliminal enterprises, due to their location close to residential areas or areas with a high concentration of population, pose a serious risk to the population.The paper summarizes the results of the quantitative risk assessment of a specific enterprise not included in the Seveso Directive – a filling station. Filling stations are frequently located in built-up areas with a dense coefficient of habitability. Due to their number, location (e.g. close to residential areas), frequency of occurrence of persons in the area and handling of dangerous substances during normal operation, they can have negative or even tragic consequences to the life and health of the population.Due to the non-existent risk assessment methodology for enterprises with subliminal quantities of dangerous substances and the lack of a systematic search for risk sources, a risk assessment procedure for these companies is designed.