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abstract: Buildings are composed of several systems, each with specific designs and regulations to ensure that constructions are safe and viable. Many residential, commercial, and industrial buildings have systems with gas central storage, which must be subjected to strict safety criteria to avoid accidents. In addition to the safety mechanisms provided by manufacturers, designers of these gas central storage must consider other devices to reduce explosion risk and mitigate the damaging blast effects. Explosions are physical-chemical phenomena that are characterized by the sudden expansion of a material and, consequently, energy release. When an accidental explosion occurs, much damage is caused by the shock wave and fragments. In the case of pressure vessels, a mechanical explosion can occur. Studying this explosion is essential to developing a more reliable, safe design for surrounding buildings and its users. This work aims to study the effects of gas tank explosions. In this study, the Autodyn computational tool based on fluid dynamics (CFD) is used. This software allows the modeling of complex explosion scenarios and the evaluation of blast wave parameters. For each numerical model, the overpressure levels outdoors and indoors are evaluated. The results indicated how the wave overpressures are distributed in different scenarios, and from them, it was possible to analyze the damaging levels.

The availability of accurate and robust models for the prediction of the behavior of pressurized tanks under fire exposure is a key requirement to improve the design of fire protection systems. Most of the models present in the literature take into consideration fully engulfing pool fire scenarios only. In the present study, a CFD modelling approach previously validated against full engulfing pool fire tests is used to simulate partial engulfment conditions. The model allowed analyzing local flow field promoting thermal stratification, which in turn drives internal pressurization of the tank. Comparison with fire test results shows good agreement with experimental measurements both in terms of temperature and pressurization curves. The results obtained represent a valuable source of information to support risk management, planning of emergency response and improve fire protection systems design. [ABSTRACT FROM AUTHOR]

Investigation of past accidents has shown that LPG tank accidents cause significant damage to the industry due to the storage of large volumes of flammable materials in them. This study aimed for developing a predictive accident model for dynamic risk assessment of propane storage tanks of the refinery. Hazards and safety barriers were identified using MIMAH methodology. The basis of MIMAH methodology is Bow-tie method. To construct the Bow-tie diagram, first, accidents that occurred on LPG tanks were extracted from the databases of accidents and valid sources. The top events of the accidents were identified and analyzed by the fault tree. The Bow-tie diagrams were constructed and the barriers on the diagrams were identified and verified by refinery experts. According to the SHIPP model, safety barriers were categorized into seven main barriers. The failure rates of the fault tree basic events were extracted from reliable sources and the prior probability of barriers was calculated. Based on the failure or success of safety barriers, 6 levels of severity of consequences, safe, near miss, mishap, incident, and catastrophic accident were considered. Using the prior probability of failure of the barriers, the probability of occurrence of each level of severity of consequences was calculated with the event tree. In the next step, this paper employed LPG storage tanks past accidents to construct a likelihood function and update prior probability using the Bayesian equation. Finally, the posterior probability of occurrence of the consequences was calculated using the posterior probability of failure of the barriers. Because LPG accidents occur with low probability and high severity, predicting accidents dynamically helps people to always be prepared to prevent their occurrence. [ABSTRACT FROM AUTHOR]

Background and aims: Accidents happened as a result of LPG leakage emphasizes the importance of the consequence analysis of fire and explosion in LPG storage tanks. The purpose of this study is to analysis the consequences of fire and explosion in a cylindrical LPG storage tank in an oil and gas industry. Method: In this analytical study, four possible failure scenarios including 1) rupture in the cylindrical LPG tank 2) leakage from the loading line 3) leakage from the tank manhole and 4) undesirable opening of the safety valve, and their fire and explosion consequences were simulated by PHAST software. Then the results were compared with existing standards Results: The scenario of tank rupture leads to a radiation flux 37.5 kw/m2 affect a radius of 290 m from tank location that can cause major life and property losses. As the result of a flash fire due to the tanker rupture, there is a possibility of life-threatening to a radius of 520 m. An explosion (resulting from the tank rupture) with blast wave of 0.2 bar affect a radius of 2092 m that can cause the life and property losses. The scenario of leakage from the tank manhole leads to jet fire, explosion and flash fire. Also, the jet fire and flash fire will follow by the scenarios of leakage from the loading and undesirable opening of the safety valve. Conclusion: With attention to severity the tank rupture and the likelihood of occurrence of the domino effect, it is recommended to substitute the horizontal cylindrical LPG tanks by the spherical ones. Also, an emergency response plan should be established based on the result of this study. Keywords: Consequence Analysis, Fire, Explosion, LPG Tank, PHAST

The safety of small and medium LPG (liquefied petroleum gas) storage tanks in civil and industrial facilities when affected by forest fires in the framework of Wildland-Urban Interface (WUI) was investigated. Large scale experimental tests were carried to characterize the behavior of LPG tanks in case of distant source radiation caused by forest fires. A data set was obtained and used for the validation of a dedicated two-dimensional computational fluid dynamic (2D CFD) model for the analysis of pressure build-up in vessels exposed to different types of transient h eat radiation, featuring different geometry types and operating conditions. The combined experimental and numerical analysis allowed determining the critical exposure conditions for LPG vessels. Specific key performance indicators were defined and calculated on the basis of 2D CFD simulation results in order to derive conservative indications on failure conditions of LPG storage vessels induced by forest fires. [ABSTRACT FROM AUTHOR]

The presented experimental study was launched based on the LPG explosion accident near the city of Wenling, China, in June 2020. Multiple measurement methods have been coordinated in the experiments to capture different parameters. The damage size on the vessel is varied with replaceable rupture modules. The results show that the size of the damage is a decisive factor for distinguishing the outcome of the gas-releasing processes from a continuous discharging to a blowdown depressurization. The optical measurement illustrates the distributions of the released gas and indicates a much higher explosion potential of blowdown depressurization than continuous discharging. The experimental results confirm the rapid temperature drop due to the LPG-releasing, which has led to the embrittlement of the structure materials and was able to enlarge the damage size of the LPG tank. This new finding can largely increase the damage size on the tank and change the release process to blowdown depressurization. The damage escalation on the pressurized tank due to gas-release processes reveals the mechanism causing the disintegration of the tank as well as the severe explosion in the Wenling accident. According to the results, low alloy steel is not recommended for the structural material of LPG tanks. [Display omitted] • Experiment for simulating and investigating LPG depressurization in an accident. • Coordinated measurement methods for capturing the releasing gas flow behaviors. • Damage larger than 1.5‰ of the tank surface leads to high VCE potential of LPG. • Rapid temperature drops due to gas-releasing lead to embrittlement of the tank. • Revealing the depressurization-escalated damage of the tank in the real accident. [ABSTRACT FROM AUTHOR]

In recent years, many explosion accidents of LPG (Liquefied Petroleum Gas) tank happen due to fires, temperature-pressure-stress coupled field parameters of LPG tank under fire change nonlinearly, which are affected by many factors, such as fire type and filling rate. In order to improve the computing efficiency, the Legendre wavelet function is combined with traditional finite element to construct the Legendre finite element, and the effect of every affecting factor on changing rule of coupled field of LPG tank under fire can be analyzed effectively. First, the basic property of Legendre wavelet is analyzed. Second, temperature–pressure–stress-coupled model of LPG under fire is constructed; the temperature-pressure-stress coupled Legendre wavelet finite element is established; and then the effect of every affecting factor on coupled field of LPG tank under fire is obtained. Results show that analysis precision based on Legendre wavelet finite element method can be improved effectively. [ABSTRACT FROM AUTHOR]