Gasoline Pool Fires Research Articles

Preparation of novel gel foam and its fire suppression performance against gasoline pool fires

The phenomenon of re-ignition after extinguishing tank fires poses a significant challenge for firefighting and rescue operations. In this study, a gel foam was prepared using linseed gum as the gelling agent and sodium tetraborate as the cross-linking agent. By analyzing the foaming performance of the gel foam, the optimal formulation for the gel foam was determined. Subsequently, microscopic structural observations and thermal stability tests were conducted on this material. A comparison of the firefighting performance between the gel foam and aqueous film-forming foam (AFFF) on extinguishing gasoline pool fires was also carried out. The results indicate when the foaming agent, consisting of coconut oil glucoside (APG0814) and fatty alcohol polyoxyethylene ether (AEO-9), is used in a 9:1 ratio with a mass fraction of 0.4 wt%. Furthermore, by introducing 0.35 wt% concentration of linseed gum and 0.02 wt% concentration of sodium tetraborate, the gel foam exhibits a foaming expansion ratio of 6.5, a half-life of 203 min, and a comprehensive value of 989.63, which represents the best performance. The gel foam and the AFFF exhibit relatively similar extinguishing effectiveness, with respective extinguishing times of 108s and 95s.Further analysis of the gel foam's resistance to re-ignition reveals that the gel foam demonstrates 25 % and 90 % ignition resistance times of 425s and 573s, respectively, representing a significant enhancement of 66.02 % and 104.64 % compared to the AFFF. These results indicate that the novel gel foam possesses excellent resistance to re-ignition, reducing the risk of fire rekindling in liquid fire scenarios. This research serves as a valuable reference for the development of environmentally friendly and re-ignition-resistant gel foam for extinguishing liquid fires.

Experimental study and new-proposed characterization of burning rate and flame geometry of gasoline pool fires with different aspect ratios

This study investigated the burning rate and the flame geometry of gasoline pool fires under crosswinds in the context of bridge vehicle fires. A 1:4 scale bridge fire platform was established. A total of 45 fire experiments were conducted on 9 gasoline pool with 1–2.2 aspect ratios under 0–2 m/s cross-wind. The influence mechanism of aspect ratio n on the characteristic parameters of pool fires was investigated. The results showed that the burning rate of gasoline pool ranges from 0.028 kg‧m−2‧s−1 to 0.064 kg‧m−2‧s−1, which increases with wind speed and pool size. When the wind speed exceeds 1 m/s, the title angle of the flame on the windward side is greater than 45° and is less affected by pool size. The wall heat conduction at wind downstream increases with aspect ratio when placing the longer side facing to cross flow. The correction factor Fr·n can be used to describe the competition between the air entrainment and the buoyancy in gasoline pool fire. A general model based on aspect ratio is proposed to quantify the burning rate and flame tilt characteristics of gasoline fires. The reliability and applicability of the model are compared with the existing experimental data.

Heat release rate prediction for high-altitude gasoline pool fires based on field tests of combustion characteristics

The heat release rate is of great significance for fire protection design, whether in highway tunnel, building, oil depot and aircraft. Simply, the heat release rate can be estimated by multiplying the mass loss rate by the effective heat of combustion, which can be investigated via pool fire test, because of its wide applicability in various fire scenarios. In fact, both mass loss rate and effective heat of combustion are affected by the high-altitude environment, including the low atmospheric pressure and low ambient temperature. Thus, to obtain the mass loss rate and effective heat of combustion, field tests of gasoline pool fire were conducted at 4 altitudes. The test environments of 4 altitudes were consistent with that of real fires at high altitudes, especially the atmospheric pressure and ambient temperature, to ensure that the measuring data were correct. The heat release rate at high altitudes were calculated by using the fitting formulas of mass loss rate and effective heat of combustion, which were presented in this paper. The results revealed the following: (1) Both the atmospheric pressure and ambient temperature were important factors for the mass loss rate and effective heat of combustion. (2) Based on a global model and flame temperature correlation, a mass loss rate estimation method was established. After analysis, a linear relationship between lnm˙ and lnP∞ was identified for temperature greater than 0 °C, otherwise, there was a logarithmic relationship between lnm˙ and lnP∞. In addition, the fitting formula of mass loss rate was obtained. (3) A theoretical method of effective heat of combustion based on the Gibbs energy minimization approach was established. For simplification, the effects of atmospheric pressure and ambient temperature were approximately independent. The effective heat of combustion increased linearly with both atmospheric pressure and ambient temperature, and the fitting formula was gained by considering above two factors. (4) The heat release rates of gasoline pool fire at high altitudes were calculated, which varied with ambient temperature as the Gaussian function. And the relationship between heat release rate and atmospheric pressure was power function. The atmospheric pressure effect on heat release rate was more significant at temperatures lower than 10 °C. The results in this work could provide a basis for heat release rate prediction studies and subsequent research on smoke diffusion, whether in aircraft, highway tunnel, building and oil depot at high altitudes.

Experimental study of the burning behavior and key parameters of gasoline pool fires with different ullage heights

Pool fires with different ullage heights are a common type of fire accident. A series of gasoline pool fire experiments with two sizes (D = 40 cm, 60 cm) and six ullage heights (h = 0, 0.2D, 0.4D, 0.6D, 0.8D, 1.0D) are conducted. The burning process, axial temperature profile, radiative heat feedback, and burning rate are measured and analyzed. The result shows that the fuel vapor layer and the down-reaching flame layer are distinguished based on the axial temperature profile for the steady burning stage. Meanwhile, the down-reaching flame length (Ldown) increases more profoundly for large tank diameters under the same ullage height. Subsequently, the dimensionless down-reaching flame length (Ldown* = Ldown/D) increases exponentially with the dimensionless ullage heights (h* = h/D). Finally, based on the classical burning rate model for the low ullage height and the heat transfer process from the flame to the fuel surface, a correlation with different ullage heights is established to calculate the burning rate, which is then validated against the experimental data in the paper and literature values. The results are of importance to understand the burning rate and the radiative heat feedback to the fuel surface for pool fires with different ullage heights.

Experimental field study on smoke characteristics and CO concentration of high-altitude tunnel fires induced using gasoline and diesel

High-altitude environments exhibit reduced atmospheric pressure, low oxygen density, and low air temperature conditions, which considerably affect tunnel fire characteristics. In this study, small-scale tunnel fire field experiments were performed at high altitudes to investigate the heat release rate (HRR), smoke temperature, and CO concentration of gasoline and diesel pool fires. The results revealed that with the increase in altitude, the HRR declined but the combustion duration increased. Furthermore, the maximum ceiling temperature decreased with the increase in altitude. The longitudinal ceiling temperature declined slowly in the high-altitude tunnel. By contrast, the smoke temperature spread rapidly among the cross-section in the high-altitude tunnel. The ceiling CO concentration behaviors for gasoline and diesel pool fires were categorized into four and three stages, respectively. Furthermore, the steady ceiling CO concentration and the maximum ceiling CO concentration decreased slightly with the increase in the altitude for gasoline pool fires, whereas the differences were greater for diesel pool fires. However, the steady ceiling CO concentration per unit mass burning rate increased linearly with the altitude for both fuels. The results revealed that the steady CO concentration at the height of 110 mm in the cross-section was nearly identical for various altitudes in the case of gasoline pool fires. However, for diesel pool fires, the CO concentration was higher at higher altitudes.

Experiment Study on the Effectiveness of Various and Mixed Kinds of Low Expansion Foam of 120# Gasoline Pool Fire Suppression

Storage tank fires can endanger society and the environment by generating intense heat radiation, rapidly spreading blazes, and cataclysmic explosions. Various types of foam and even two or more mixed foams are commonly used in storage tank fire disposal sites. This research aims to experimentally and analytically assess the efficacy of various and mixed forms of foam in putting out 120# gasoline pool fires. A series of foam fire extinguishing and re-ignition tests were conducted using a laboratory fire-extinguishing device that gently released low-expansion foam. In this work, a 2.4 m-diameter steel round tray was utilized to model the full-surface fire of an oilcan in a large oil depot base. The non-dimensional (T* = TExtinguishing/Tboiling point) average temperature of 0.62–0.66 is used in this study to represent the fire extinguishing temperatures of 120# gasoline fuel. The power law is still followed during the spreading phase as the length of the foam spreads further with time. When combined, 6% aqueous film-forming foam solution and alcohol-resistant aqueous film-forming foam solution (AFFF + AFFF/AR) have the highest flow velocity of 0.0189 m s−1. According to the results, synthesis foam solution combined with alcohol-resistant fluoroprotein foam (S + FP/AR) provided the greatest cooling effect, followed by S + S/AR (alcohol-resistant synthetic foam solution), AFFF/AR, S + AFFF, S/AR + AFFF, and finally S/AR + AFFF. According to the results, foam with an expansion ratio of 8.7:1 (FP (fluoroprotein foam solution) + AFFF/AR) has greater re-ignition resistance and burn-back protection. A referable tactic for choosing foam for liquid fire suppression is shown in this paper. The results suggested that FP and AFFF should be used for effective fire suppression in this hydrocarbon fuel fire rescue. Then, we can use synthetic foam and AR foams to provide continuous cooling and prevent the fire from re-igniting through efficient foam coverage.

An experimental study on the thermal radiation attenuation effect of water mist from flat fan nozzle

The factors which influence the radiation attenuation efficiency of the water mist from flat fan nozzle have been investigated in the study. The characteristic parameters of the water mist were obtained by laser-based diagnostic system for flow field. Both blackbody furnace and gasoline pool fires were used as heat sources in the experiments. The influences of system pressure, the vertical distance from the nozzle, the temperature of the radiation source and the number of the mist layers on the radiation attenuation effectiveness have been systematically studied. The experimental results showed that when the vertical distance down the nozzle increased from 20 cm to 200 cm, the radiation attenuation efficiency increased at first, then remained almost stable for a substantial distance and decreased afterwards, and three vertical zones were identified based on the attenuation characteristics; as the temperature of the blackbody furnace radiation aperture increased from 1000 ℃ to 1300 ℃, the radiation attenuation efficiency had a certain decrease, a linear correlation was found between the mitigation rate and the radiative source temperature under different system pressures. The attenuation effectiveness improved with the increase of both system pressure and the number (thickness) of water mist layer, while the augmentation rate in attenuation slowed as the system pressure and the water mist thickness increased. The findings provide useful insights into the optimization of attenuation performance of water mist and potentially contribute to the protection against thermal radiation in fields like the fluorine chemical industry.

Bench-scale fuel fire test for materials of rechargeable energy storage system housings

The fire behaviour of electric vehicles (EVs) differs from that of vehicles with combustion engines. Especially the rechargeable energy storage system (REESS) requires special fire protection measures. The fire behaviour of materials for REESS housings plays an important role in the fire resistance of such systems. Full-scale fire resistance tests like gasoline pool fire tests on complete REESS according to the UNECE-R100-8E standard are mandatory for EVs. However, these tests are not applicable for materials used for REESS housings in the material and process development state, due to the high material demand and production costs of the REESS. Standard tests like the limiting oxygen index test, UL94-V test or cone calorimeter test are insufficient to analyse the fire behaviour of thermoplastic and thermoset materials in a gasoline pool fire. This paper describes a bench-scale fuel fire test including several test criteria to evaluate materials for REESS housings on a laboratory scale. This bench-scale fire test is demonstrated on two case studies: fibre-reinforced thermoset plates and thermoplastic sandwich structures.

Near-Field Radiant Heat Flux from Open-Air Gasoline and Diesel Pool Fires: Modified Point Source and Discretized Solid Flame Models

This paper proposes novel modifications to existing solid flame and point source models to better predict the spatial contour of near-field, steady-state radiant heat flux from large circular pool fires (with diameters ranging from 1 m to 20 m) with gasoline and diesel fuel. The proposed models account for partial smoke obscuration of the flames, and the emissive power of the visible flame layer is calculated via a radiative fraction of the fire’s heat release rate as a function of the pool size. The modified discretized solid flame model uses a cylinder + cone shape combination whose surfaces are discretized to enable a flexible summation of total radiative energy emission. The modified point source model places its radiating point at the mid-height of the visible flame layer to capture the location of maximum radiation intensity. Predictions from both proposed models are benchmarked against available data from pool fire experiments, calibrated against computational fluid dynamic simulations, and compared with existing analytical solutions for a range of pool fire diameters at varying standoffs and gauge heights. The results demonstrate that the proposed models can effectively predict the spatial contour and peak value of radiant heat flux on nearby targets (i.e., at distances less than 2.5 times the pool diameter) with low computational effort.

Improvement in the prediction of gasoline pool fire behaviour: CFD modelling and validation

The development and implementation of mathematical models through Computational Fluid Dynamics (CFD) techniques has been acknowledged as a promising tool for the prediction of hydrocarbon pool fires behaviours. In this sense, different approaches, with different assumptions and simplifications, and accounting for different phenomena, have been developed in the literature. However, the deviations in the predictions of the experimentally determined parameters, such as temperatures profiles, flame heights and radiative heat flux, by the implemented models are still high. Therefore, the implementation of these models to predict combustion phenomena and flame behaviours for various scenarios is limited. In this work, the software C3D is used to model gasoline pool fires of different diameters, and under different wind conditions, in order to improve the quality of the predictions of the flame behaviour. The modelled cases correspond to the experimental studies reported in literature. The results from the implemented model show an improved predictive quality when compared with other modelling works reported on literature for the same experimental cases. The deviations in the time averaged temperature, flame height, surface emissive power and radiative heat flux, has been calculated to be 5.0%, 0.05%, 6.32% and 3.82%, respectively.

Estimating water density for tunnel fixed firefighting system and ventilation requirements to control fires in road tunnels

A potentially dangerous fire event that can occur in road tunnels is a gasoline tanker fire, where flammable liquid fuel spills on the tunnel roadbed and catches fire. In the USA typically, the water density required for fixed firefighting systems is based on NFPA 13 and the minimum ventilation is based on smoke back layering. This work calculates the required water density based on the tunnel geometry and compares the back layering ventilation to the ventilation needed to remove saturated air. The presented methodology presents an analytical approach to calculate the water density and ventilation required to control a gasoline pool fire, which is a function of the size of the gasoline pool, without considering the growth restriction due to fuel depth and limited oxygen.The tunnel geometry parameters presented in the examples are limited to specific cross slopes and road slopes, as well as resultant fire sizes of 50 MW, 100 MW, and 150 MW. This work considers standard sprinkler heads to calculate the required density in conjunction with the ventilation required to maintain evaporative cooling. The calculations are performed with a water only system and with modifications that could be expected from the use of foam additive.

Why are cooktop fires so hazardous?

A series of experiments was conducted characterizing the flammability properties of small-scale corn oil fires. The oil was placed in a pan located on the center of an electric coil heating element associated with an electric cooktop. Ignition was accomplished with a torch with the heating element off or by auto-ignition when the heating element was on. The mass loss, heat release rate, pan bottom temperature, heat flux to the surroundings, and flame height were measured. The radiative fraction and combustion efficiency were estimated from the measurements. Heating the oil on a typical electric cooktop leads to auto-ignition of the oil. Continued heating of the oil on the cooktop enhances the vaporization of the oil and leads to rapidly growing fires with relatively large peak heat release rates. Under some conditions, heated corn oil can boil-over, a phenomenon in which the oil bulk density decreases until it flows over the pan sides. For a given pan volume, the occurrence of boil-over depends on the initial fuel volume. Compared to traditional gasoline pool fires, the corn oil undergoing auto-ignition and continued heating had larger peak values of heat release rate and peak flame height by factors of 3.1 and 1.6, respectively.

Development of Experimental Apparatus for Fire Resistance Test of Rechargeable Energy Storage System in xEV

To secure the safety of xEV (all types of electrical vehicles), the United Nations released Global Technical Regulation No. 20, “Global Technical Regulations on the EVS (Electric Vehicle Safety)” in March 2018. The fire resistance test of the rechargeable energy storage system (REESS) describes an experimental procedure to evaluate the safety performance—specifically, whether passengers would have sufficient time to escape from the xEV before the explosion of the battery in a fire. There are two options for component-based REESS fire resistance tests: a gasoline pool fire and a liquefied petroleum gas (LPG) burner. This study describes the process for optimizing the specifications of the fire resistance test apparatus for xEV batteries using an LPG burner, which was first proposed by the Republic of Korea. Based on the results of the measurement and a computational fluid dynamics analysis of the prototype test apparatus, new equipment designs were proposed by determining the nozzle spacing and number, fuel flow rate, and experimental conditions. To cover a wide range of xEV battery sizes, a final test apparatus consisting of 625 burners was selected. For three different battery sizes, it was possible to satisfy the temperature requirements, ranging from 800 to 1000 °C, of the GTR fire resistance test. The final apparatus design developed in the present study has been included in GTR No. 20 for EVS since March 2018.

Fire Size of Gasoline Pool Fires.

This article presents an experimental investigation of the flame characteristics of the gasoline pool fire. A series of experiments with different pool sizes and mixture contents were conducted to study the combustion behavior of pool fires in atmospheric conditions. The initial pool area of 0.25 m2, 0.66 m2, and 2.8 m2, the initial volume of fuel and time of burning process, and the initial gasoline thickness of 20 mm were determined in each experiment. The fire models are defined by the European standard EN 3 and were used to model fire of the class MB (model liquid fire for the fire area 0.25 m2), of the class 21B (model liquid fire for the fire area 0.66 m2), and 89B (model liquid fire for the fire area 2.8 m2). The fire models were used to class 21B and 89B for fuel by Standard EN 3. The flame geometrical characteristics were recorded by a CCD (charge-coupled device) digital camera. The results show turbulent flame with constant loss burning rate per area, different flame height, and different heat release rate. Regression rate increases linearly with increasing pans diameter. The results show a linear dependence of the HRR (heat release rate) depending on the fire area (average 2.6 times).

Experimental study on the smoke temperature evolution in a polyethylene (PE)-lined compartment on fire

Smoke temperature evolution in the upper layer of compartment fire, which is critical for the prediction of potential flashover, was experimentally investigated in a real building. Three-millimeter polyethylene (PE) slabs attached on the internal walls were employed as the lining material to address the effect of the melting and combustion of the lining material on the smoke temperature. A corner gasoline pool fire was utilized as the fire source. Two thermocouple trees, mounted vertically at the center and the open door, and a high-definition camera were utilized to record the smoke temperature history and experimental video. Meanwhile, some furniture was loaded to study its enhancement feature on fire intensity. Heat release rates (HRRs) at different stages were analyzed based on MQH method (McCaffrey, Quintiere and Harkleroad) and pool fire theory. Smoke temperature was estimated through an improved MQH correlation considering the melting of the PE slabs and an empirical model, BFD curve (Barnett in Fire Saf J 37: 437–463, 2002) combined. The results show that both the maximum HRR and smoke temperature, 925.91 kW and 491.7 °C, are lower than the critical values of flashover. The PE lining greatly intensifies the fire power and the resulting smoke temperature compared with the ones in noncombustible wall scenario. Combustion of the molten PE flowing down from the walls would lead to a secondary peak in smoke temperature curve, which is rarely considered in previous work.

Analysis on the Results of Measured Concentration of the Combustion Gases Considering Respiration Characteristics in Gasoline Pool Fire

Analysis on the Results of Measured Concentration of the Combustion Gases Considering Respiration Characteristics in Gasoline Pool Fire

Experimental and numerical study on smoke evolution in polyethylene (PE) slabs enclosed compartment fire

ABSTRACT Full-scale compartment fire experiment initiated by a corner gasoline pool fire was conducted to investigate the enhancement effect of polyethylene (PE) slabs attached on the internal walls on fire development and smoke evolution. An open door and an initially closed window served as the openings to provide natural ventilation condition. Corresponding numerical simulations, employing a CFD tool Fire Dynamics Simulation (FDS), were carried out as well to study the fire growth, smoke temperature, smoke layer height, and indoor visibility. Both PE and non-PE compartment fire circumstances were simulated to examine the intensifying mechanism of burning PE slabs. The results show that the attached PE slabs on the walls would greatly intensify the compartment fire and result in a much higher smoke temperature by about 325 °C, which could significantly facilitate the potential occurrence of flashover. The molten PE generated a considerable pool fire on the floor and resulted in a secondary peak in smoke temperature curve after the burnout of gasoline. However, this secondary peak is not found in the simulation results due to the neglect of melting and flowing process in numerical model. Some random ignition incidents in test, such as the splash of pool fire and collapse of furniture, contributed to the deviation between experimental and numerical results. Smoke layer height was empirically estimated to be 1.8 m and compared with numerical predictions. The empirical model predicted the smoke layer height well after the break of window at the steady state.

Experimental studies on characteristics of fire whirl in a vertical shaft

SummaryAn internal fire whirl can be generated readily in a tall shaft model with appropriate gap width at one corner. Experimental study was carried out to investigate the relationship between the characteristics of an IFW and the corner gap width in a 9‐m‐tall vertical shaft model. The vertical shaft had a 2.1 m by 2.1 m square section with gasoline pool fire of different diameters burning inside. The gap width was varied to investigate its impact on fire whirl characteristics, such as flame development, swirling intensity, flame height, flame temperature, and heat release rate of the gasoline pool fire. Vigorous flame swirling motions were generated when the ratio of the gap width to the shaft section perimeter was within the range 0.16 to 0.21. From the flame streamline angle, it was observed that the swirling component was much stronger than buoyancy component near the bottom of burning region. The swirling component decreased and became roughly the same as buoyancy near the middle. Finally, it diminished to being much weaker than buoyancy near the top of the fire. These observations suggest that the Froude number Fr decreased from a large number to 1, and then continued to decrease to 0.

Fire Model Test on Temperature Field in the Rescue Station of an Extralong Railway Tunnel

A rescue station is necessary for an extralong railway tunnel, whose length is generally greater than 20 km. In the rescue station, passenger evacuation, fire fighting, and protection of passengers are organized. It is important to discover the temperature distribution in a rescue station where a train is on fire. This paper performs a similarity simulation model test at 1 : 10 geometric scale to investigate the temperature field in a rescue station. A gasoline pool fire was used as the fire source. The influences of the fire source position and ventilation condition on the temperature field were studied. The results show that (a) the temperature distribution along the tunnel is stable without ventilation, the temperature is lowest when the fire occurs 50 m from the entrance; (b) the fresh air stirred up by fans promotes burning and increases the temperature; (c) the chimney effect causes the temperature field to skew in an uphill direction; (d) the opening of both fans in the adit makes the high‐temperature zone to connect through; and (e) the temperature increase at the rescue station can be divided into four stages, and the response of different fire source positions to the opening of fans is not consistent. These findings provide a basis for personnel escape design and a foundation for further study of temperature distribution in a tunnel with a rescue station.

Experimental study on the smoke temperature distribution alongside the lining in tunnel fires

Tunnel fire temperature is a key factor for tunnel structural safety and evacuation. This study aimed to investigate the smoke temperature distribution alongside the lining across the section and effects of pool sizes and fuels on it through a series of small-scale experiments. The results showed the heat release rates of diesel were significantly lower than gasoline?s when they had the same pool size and volume. Nevertheless, the duration of diesel combustion increased obviously. As a result, the maximum smoke temperature under the ceiling for gasoline was significantly higher than diesel?s. The results were subsequently adopted to compare with other test results and illustrated a similar result. The initial temperature rising rates for gasoline pool fires were shown to agree well with the standardized temperature curves, but they were significantly lower for diesel pool fires. Two exponential correlations on vertical temperature distribution were provided, respectively, for gasoline and diesel fires. These findings are expected to be useful for the design of the thermal boundary on the lining in tunnel fires.