Multiple pool fires: Occurrence, simulation, modeling and management

Fuzzy Bayesian estimation and consequence modeling of the domino effects of methanol storage tanks

In this study, a fuzzy Bayesian network (FBN) approach was proposed to analyze the domino effects of pool fire. Failure probabilities were calculated using triangular fuzzy numbers, the combined center of area (CoA)/sum-product method and the BN approach. Consequence modeling, probit equations and leaky-noisy-OR (L-NOR) gates were used to analyze the domino effects, and modify conditional probability tables (CPTs). Methanol storage tanks were selected to confirm the practical feasibility of the suggested method. The domino probability using bow-tie analysis (BTA) and FBN in the first and second levels was compared, and the ratio of variation was used for sensitivity analysis. Probability of the domino effect in the first and second levels (FBN) was 0.0071472631 and 0.0090630640, respectively. The results confirm this method is a suitable tool for analyzing the domino effects and that using FBN and L-NOR gate is a good way to assess the reliability of tanks.

Effects of pool size and spacing on burning rate and flame height of two square heptane pool fires

The interaction of multiple pool fires might lead to higher burning rate and flame height than single pool fire, raising the possibility of fire ignition and flame spread and increasing the risks to people, buildings and environment. To quantify the burning rate and flame height of multiple pool fires from the view of physical mechanism, this paper presents an experimental study on two identical square pool fires. Heptane was used as fuel. The pool size and spacing were varied. Results showed that both the burning rate and flame height change non-monotonically with spacing. From the view of air entrainment, a correlation for the flame height of two pool fires is developed involving pool size, spacing and the flame height of zero spacing. The comparison with experimental results shows that the developed correlation is suitable for two heptane or propane fires. A theoretical study based on energy balance at one of the pool surfaces is performed to evaluate the burning rate of two fires, which is finally expressed as a function of pool size, spacing, burning rate and the flame height of single fire. The proposed model is validated using the experimental and literature data, which presents a reasonable reliability.

Characteristics of multiple pool fires in a tunnel with natural ventilation

Tunnel fires are usually accompanied with major casualties and properties losses, and multiple fires in a tunnel may cause intense burning behavior like fire merging, which could be more destructive and hazardous. Therefore, the characteristics and hazards of multiple pool fires in a tunnel were investigated under natural ventilation in this study through a series of experiments. Experimental results showed that the characteristics of one-dimensional fire arrays were different from those of square fire arrays in open space. Due to the extra heat feedbacks (e.g. from adjacent fire sources, tunnel wall and hot smoke), the burning rate was found being enhanced. When there is more than one fire source, it was observed that the flames deflect towards the center of one-dimensional fire arrays, leading to flame merging when fire spacing decrease to some extent, which would result in the increased hazards of the heptane fires. An empirical model was developed to predict the global dimensionless average burning rates based on modified fire area ratio, which characterizes the fuel load and incorporated fire spacing, fire number and the fuel pan size. The research results in this paper provide a theoretical guide on understanding the behaviors of multiple fire resources in tunnels.

Computational Assessment of the Hazardous Release Dispersion from a Diesel Pool Fire in a Complex Building’s Area

A hazardous release accident taking place within the complex morphology of an urban setting could cause grave damage both to the population’s safety and to the environment. An unpredicted accident constitutes a complicated physical phenomenon with unanticipated outcomes. This is because, in the event of an unforeseen accident, the dispersion of the hazardous materials exhausted in the environment is determined by unstable parameters such as the wind flow and the complex turbulent diffusion around urban blocks of buildings. Our case study focused on a diesel pool fire accident that occured between an array of nine cubical buildings. The accident was studied with a Large eddy Simulation model based on the Fire Dynamics Simulation method. This model was successfully compared against the nine cubes of the Silsoe experiment. The model’s results were used for the determination of the immediately dangerous to life or health smoke zones of the accident. It was found that the urban geometry defined the hazardous gasses dispersion, thus increasing the toxic mass concentration around the buildings.