Fire Extinguishing Performance Research Articles

Environmentally friendly fluorine-free fire extinguishing agent based on the synergistic effect of silicone, hydrocarbon surfactants and foam stabilizers

The environmentally friendly fluorine-free fire extinguishing agent based on the silicone surfactant was developed in order to solve the environmental hazards and bio-accumulative of traditional aqueous film-forming foam (AFFF). The carboxyl modified polyether polysiloxane surfactant (CMPS) was an efficient alternative to fluorocarbon surfactant, which was firstly synthesized via the esterification reaction using hydroxyl-containing polyether modified polysiloxane (HPMS) and maleic anhydride (MA) as raw materials. Then the surface activity, foam properties, micellar morphology of the CMPS and four hydrocarbon surfactants, as well as their mixture are evaluated by surface tension, Ross-Miles and cryo-transmission electron microscopy (Cryo-TEM). And the suitable key amount of CMPS and hydrocarbon surfactants added to the extinguishing agent were optimized by orthogonal tests. Moreover, the effect of foam stabilizer on the surface activity, foam property and fire extinguishing performance of fire extinguishing agent are also analyzed. Consequently, a new environmentally friendly fluorine-free fire extinguishing agent was prepared and the surface tension, the interfacial tension, foam properties, bubble morphology, spreading behavior and fire extinguishing mechanism were systematically characterized. The Cryo-TEM results illustrate that the intense interaction among silicone and hydrocarbon molecules exists in the the mixture of CMPS and hydrocarbon surfactants, which is produced through the change of micellar morphology, i.e. microscopic larger spheroidal micelles of CMPS transited to smaller spheroidal micelles and wormlike micelles in the mixed system. The surface tension of synthesized foam extinguishing agent is 22.3 mN/m and the spread coefficient is 0.9 mN/m, which has excellent surface activity and spreading property. The prepared foam extinguishing agent exhibits superior fire-fighting property, which can be attributed to the high surface activity, good foam property and superior foam stability. The research results of this paper lay a theoretical foundation for the research and development of efficient environmentally friendly foam extinguishing agent.

Design of fluorine-free foam extinguishing agent with high surface activity, foam stability and pool fire suppression by optimization of surfactant composition and foam system

To meet the environmental requirement of foam extinguishing agent, a novel fluorine-free surfactant named amino-terminated polyether modified silicone (ATPMS) was successfully synthesized, and then in combination with hydrocarbon surfactant prepared fluorine-free foam extinguishing agent. The study carefully investigated surface tension, foamability, foam stability and fire extinguishing performance of fluorine-free foam extinguishing agent. The results indicate that ATPMS has a low surface tension of 21.17 mN/m, which combined with hydrocarbon surfactant at the mass concentration ratio of 1:1 imparts high surface activity. The sodium lauryl ether sulfate (AES)/ATPMS system owes the optimal comprehensive performance with an initial foam height value of 85.8 mm, a surface tension value of 24.76 mN/m and a foam stability value (the ratio of foam height between initial foam and five-minute foam) of 64.0 % at critical micelle concentration (CMC), respectively. Fire suppression test shows that the obtained fluorine-free foam extinguishing agent is effective in fighting diesel pool fires. The firefighting efficiency of foam agent links to the mixing chamber structure of compressed air foam fire extinguishing system (CAFS). When the mixing chamber of CAFS has a recurrent segment length of 50 mm and the filled particle size of 10 mm, the firefighting efficiency of fluorine-free foam extinguishing agent is optimal with a fire extinguishing time of 33 s and a temperature drop rate of 6.49 °C/s.

Analysis of fire extinguishing performance and mechanisms in transformer oil pool fires by large-scale compressed nitrogen foam: Impact of different nozzle pressures

This article investigates the suppression of transformer oil pool fires using compressed nitrogen aqueous film-forming foam extinguishing agents with varying nozzle pressures (0.1–0.4 MPa), and a comprehensive analysis of fire extinguishing behavior and resistance to re-ignition was conducted. The research findings indicate that at a nozzle pressure of 0.4 MPa, there is a significant enhancement in fire extinguishing efficiency, with a reduction in extinguishing time by 15.0%–29.2%, and an increase in resistance to re-ignition by 32.2%–48.2%, making it the optimal choice. In comparison to the 0.1 MPa condition, the maximum instantaneous emissions of CO and SO2 at 0.4 MPa are only 66.7%. The interaction of various effects, such as atomization, results in a significant enhancement of flame intensification and fire extinguishing effects when compressed nitrogen aqueous film-forming foam is sprayed at high nozzle pressures. The study provides valuable insights for firefighters in the practical use of foam extinguishing agents.

Fluorine-free foaming extinguishing agent: Design route, fire extinguishing performance, foam stability mechanism

The development of fluorine-free foaming extinguishing agent, abbreviation FFEA, has become an urgent scientific challenge in the field of fire protection engineering due to the fact that the key component of existing aqueous film-forming foams is listed as a persistent organic pollutant. A study was conducted on foam performance and fire extinguishing efficiency of FFEA prepared by hydrocarbon and silicone surfactants with low-carbon alcohol modulation, using three selected silicone surfactants. The results show that the FFEA, including low-carbon alcohol-modulated Silok8141/SDS and Silok8008/SDS, exhibit low surface tension, good foam stabilization coefficient and long foam drainage time. Laboratory foam extinguishing experiments demonstrate that the FFEA produced by Silok8141/SDS/Isobutanol ternary system has better cooling effect and fire extinguishing performance. And the study of FFEA mechanism reveals that the addition of isobutanol blocks the foam liquid channel and increases the foam stability. The wide applicability of the design route for FFEA prepared by low-carbon alcohol-regulated hydrocarbon and silicone surfactants has been demonstrated.

Wood stack fire tests to evaluate the influence of extinguishing medium and driving pressure on fire extinguishing efficacy of forest trees

In order to explore efficient fire extinguishing agents for forest fires and further enhance fire prevention and extinguishing technology, an outdoor fire extinguishing test platform for burning wood stacks is constructed to simulate fire extinguishing scenarios in an open-air environment. Comparative analysis of fire extinguishing performance of hydrogel extinguishing agent and compressed air foam (CAF), and exploring cooling effect of fire extinguishing agent on internal high temperature of wood stacks under three driving pressures of 0.45 MPa, 0.55 MPa and 0.65 MPa. Test results show that both hydrogel extinguishing agent and CAF can effectively extinguish woodpile fires. Hydrogel fire extinguishing agents are more efficient in extinguishing fires by comparing extinguishing time and agent dosage. CAF in the early stages of firefighting, there is a momentary enhancement of flame, which leads to an increase in temperature of wood stacks and heat radiation fluxes. In contrast, hydrogel fire extinguishing agents can quickly reduce temperature and heat radiation flux of wood stacks, and cooling effect is significant; When driving pressure is increased from 0.45 MPa to 0.65 MPa, the flame extinguishing time gradually decreases. Analyzing cooling capacity in terms of consumption of extinguishing agent, hydrogel extinguishing agent increases about 40 %, while cooling capacity of CAF increases only about 22 %; Hydrogel's cooling efficiency is better than CAF, and increasing driving pressure helps to improve agent cooling efficiency. Among them, CAF needs to be within a specific gas driving pressure range, which can minimize negative effect of gas driving pressure and enhance its cooling efficiency.

Study on the effects of carbon nanotubes and xanthan gum on the performance of hydrocarbon surfactant foam systems

To improve the foam stability and fire extinguishing efficiency of fluorine-free foam (FFF) extinguishing agents, xanthan gum (XG) and carbon nanotubes (CNTs) were selected as the foam stabilizer agents in this study to investigate their effects on the physical and chemical properties and fire suppression effectiveness of FFF system. The effects of the four factors, namely, α-olefin sulfonic acid Salts (AOS), YT-Y762, XG, and CNTs, on the foam performance were investigated using L9(34) orthogonal design method. Three FFF solutions were selected based on the following four parameters: surface tension, 25% drainage time, foam height, and viscosity. The physicochemical properties, fire extinguishing, and burnback performance of the three FFF solutions were investigated. The results indicated that XG and CNTs have synergistic effects on the FFF solution, and the addition of 0.2 wt% of XG and 0.4 wt% of CNTs increased the 25 % drainage time by 81.40 %. The fire extinguishing performance was effectively improved. The results show the potential application of carbon nanotubes in FFF extinguishing agents.

Experimental investigation on the dynamics of a single water droplet impacting wood surface

The dynamic characteristics of water mist droplets hitting the wood surface is one of the important factors affecting the fire extinguishing performance. However, the spreading dynamics between water droplets and wood surfaces during the impacting process have not been adequately characterized in existing literature. This study experimentally investigates the dynamic process of a single water droplet with changing Weber numbers from 66.7 to 1268.5 impacting different solid wood surface from the perspective of fire suppression. Typical impacting phenomena, the phenomena distribution, the droplet spreading dynamics and the maximum spread factor have been analyzed and discussed. Typical phenomena including no splash, transition from no splash to prompt splash, and prompt splash with varying Weber number are observed for the wood surface. The typical phenomena distribution can be distinguished by lgWe and lgRe and the result shows that lgWe < 2.11, 2.11 < lgWe < 2.42, and lgWe > 2.42 correspond to the phenomena of no splash, transition from no splash to prompt splash and prompt splash respectively. The spreading time can be predicted by the expression of ts/(ρRmax3/σ)0.5=6.52∗We-0.92. By analyzing the maximum spreading factor, the model βmax∝(We/Oh)0.198 is found to present good predictions for wood surfaces.

Research on the fire extinguishing performance of new gel foam for preventing and controlling the spontaneous combustion of coal gangue.

Coal gangue, as an associated product of coal mining, can cause a large number of piles to undergo slow oxidation and spontaneous combustion, resulting in the production of toxic and harmful gases, leading to casualties, environmental damage, and economic losses. Gel foam has been extensively employed as a fire-retardant material in coal mine fire prevention. The thermal stability and rheological properties of the newly developed gel foam were investigated in this study, as well as its oxygen barrier properties and fire extinguishing effect which were evaluated through programmed temperature rise and field fire extinguishing experiments. The experiment indicated that the temperature endurance of the new gel foam was around twice that of the ordinary gel foam, and this resistance decreased with the increment of foaming times. Moreover, the temperature endurance of the new gel foam with a stabilizer concentration of 0.5% was superior to that of 0.7% and 0.3%. Temperature has a negative effect on the rheological properties of the new gel foam, while the foam stabilizer concentration has a positive effect. The oxygen barrier performance experiment results showed that the CO release rate of coal samples treated with the new gel foam rose relatively slowly with temperature, and the CO concentration of coal samples treated with the new gel foam was only 159 ppm at 100 °C, which was significantly lower than 361.1 ppm after two-phase foam treatment and 715 ppm after water treatment. Through simulating the spontaneous combustion experiment of coal gangue, it was demonstrated that the new gel foam has a much better extinguishing effect than water and traditional two-phase foam. The new gel foam cools gradually and does not re-ignite during the fire extinguishing process, while the other two materials re-ignite after being extinguished.

Study on Ignition Delay and Reaction Mechanism of RP-3/Air Combustion Adding C6F12O.

RP-3 jet fuel is the main fuel for aircraft in China, and it is also a source of fire. C6F12O (Novec 1230) has an outstanding fire extinguishing performance and minimal environmental impacts. In this study, the application of C6F12O in the inhibition of RP-3 jet fuel fire was considered, and the ignition delay time (IDT) of C6F12O/air and RP-3/air adding C6F12O was measured using a shock tube. In addition, the results showed that the IDT of C6F12O was 500-900 μs and less sensitive to temperature compared with those of common fuels in the range of 1150-1958 K, and the influence of C6F12O on the IDT of RP-3 jet fuel was influenced by many factors including temperature, the concentration of C6F12O, and the stoichiometric ratio of RP-3 jet fuel. According to the experimental results, the mechanism of C6F12O was verified and modified, and then integrated with the mechanisms of RP-3 jet fuel; the integrated mechanism can well predict the IDT of C6F12O/air and RP-3/air adding C6F12O. This work provides a good basis for the chemical kinetics analysis of the inhibition of RP-3 jet fuel combustion by C6F12O.

Novel PFA-Based Inorganic Three-Phase Foam for Inhibiting Coal Spontaneous Combustion.

Fire accidents caused by coal spontaneous combustion usually lead to a large loss of coal resources and casualties. Not only that, the greenhouse effect is polluted while the environment is polluted. At present, the commonly used fire-extinguishing materials such as water, inhibitors, and organic foams have the disadvantages of poor stability and short fire-extinguishing cycles. It is difficult to effectively suppress coal spontaneous combustion and quickly extinguish the fire for a long time. To suppress the spontaneous combustion of coal, the research team proposed an inorganic three-phase foam with a high foam expansion rate, good cohesiveness, and excellent stability. In the formulation, pulverized fly ash (PFA) is used as the matrix, sodium dodecyl benzene sulfonate (SDBS) and α-olefin sulfonate (AOS) are used as foaming agents, curdlan is used as the foam stabilizer, and sodium silicate is the binder. The compound foaming agent with the best performance is optimized, through the two-group compounding test. The composite foaming agent's optimal compound ratio is SDBS/AOS (3:2). The optimal ratio of inorganic three-phase foam (ITPF) components was obtained through the control variable method experiment. The water-cement ratio is 5:1, the composite foaming agent is 0.2%, the curdlan is 0.5%, and the sodium silicate is 1.6%. In addition, it has been determined by experiments that ITPF has the strongest foaming ability when the pH value is 9 and the temperature is 60 °C. The fire-extinguishing performance of the new material ITPF was investigated by thermogravimetry and coal spontaneous combustion tendency test. It has been observed that the new material has the effect of cooling down and isolating coal from contact with oxygen. The results show that the new material ITPF has the potential to prevent coal spontaneous combustion.

Role of salts in fire extinguishing performance of aqueous film-forming foam (AFFF)

The active ingredients for aqueous film-forming foam (AFFF) are supplied as a concentrate, and the water used to dilute AFFF concentrates generally come from water sources around the fire site including seawater and river water. However, the effects of salt in water on fire-extinguishing performance of AFFF remain unclear. In this paper, we investigated the relationship between the interfacial properties, foam stability, and fire-extinguishing performance of three homemade AFFFs (nonionic AFFFAPG, amphoteric AFFFCAB and anionic AFFFSDS) and four commercial AFFFs. The seawater, firefighting water from different regions of China and deionized water were used to dilute AFFF concentrates. The results showed that AFFFAPG and AFFFCAB had a better performance than AFFFSDS in resisting the negative effects of salts on interfacial properties and foaming ability. In the fire-extinguishing tests, we found that dilution of AFFF with water samples containing high concentrations of Ca2+ and Mg2+ would weaken the fire-extinguishing performance. The traditional indicators characterizing the properties of foam (surface tension, liquid drainage rate, and spreading coefficient) could not explain the trend of fire extinguishing performance. The stability of AFFF in the presence of oil could be used to explain the difference in fire-extinguishing time of AFFF.

Alkaline potassium aluminum carbonate: A novel high-efficiency dry powder extinguishing agent with high heat-resistant

Alkaline potassium aluminum carbonate (KAl(OH)2CO3) has potential application as an active medium for dry powder fire extinguishing due to its special molecular structure. In this paper, the application of KAl(OH)2CO3 as a high-temperature resistant dry powder extinguishing agent is first discussed. Firstly, the pyrolysis kinetics of KAl(OH)2CO3 was explored using thermal analysis techniques, including model-free and model-fitting methods. The pyrolysis of KAl(OH)2CO3 can be divided into three stages, with E values of 357.7 and 244.8 kJ/mol for stage 1 and stage 3, respectively. Higher activation energy of KAl(OH)2CO3 (T5 wt%=550 K, Tmax=648 K) means that it will not be deactivated prematurely in the high-temperature region. Moreover, the fire-extinguishing performance of KAl(OH)2CO3 is much better than that of BC dry powder fire extinguishing agent, which can suppress n-heptane and aviation kerosene pool fires within 6.00 s and 7.21 s. The possible fire-extinguishing mechanism of KAl(OH)2CO3 is also proposed. Therefore, KAl(OH)2CO3 is expected to be a high-temperature resistant dry powder extinguishing agent, which solves the application of existing dry powder fire extinguishing agents in high-temperature areas such as aircraft engine compartments.

Improving the fire-extinguishing effect of pneumatic extinguishers with airflow-spray synergistic jet: Investigation of nozzle position and number of nozzles

The fire-extinguishing capability of the overheating 6 MF-30 pneumatic fire extinguisher needs to be improved. To enhance its fire-extinguishing capability, this study proposes a method of adding water through nozzles. The study conducted flow-field simulations to determine the appropriate nozzle position and replicate the synergistic jet effects using varying number of nozzles. Experimental studies were carried out to validate the simulation and demonstrate the efficiency of the synergistic jet in extinguishing fires directly. The findings show that placing the nozzle at the air duct outlet and using a higher number of nozzles is more efficient. Additionally, the synergistic jet has a better fire-extinguishing performance than pure airflow because of the cooling effects resulting from the water mist and collaborative action observed during the experimental studies. This research has significant implications for improving the efficiency and effectiveness of pneumatic fire extinguishers while advancing fire-extinguishing technology and firefighting technology.

Performance improvement of the dry chemical-based fire extinguishers using nanocalcium silicate synthesised from biowaste

Herein, we investigated nanocalcium silicate (nCa2SiO4) prepared from clam shells and rice husks for its utilisation as a chemical agent in a fire-extinguishing mixture comprising ABC dry powder. The fire-extinguishing performance was evaluated with Class A and B fires. The prepared mixture was compared with commercial mono-ammonium phosphate powder based on different parameters, namely extinguishing time, amount of extinguishing agent used, fire temperature reduction rate, powder coating on the fuel and a reburn incident. It was found that the mixture of nCa2SiO4 and ABC dry powder could extinguish Class A and B fires within 10.67 and 9 s, respectively, while commercial mono-ammonium phosphate powder required 11 and 11.33 s to extinguish Class A and B fires, respectively. Thus, the mixture of nCa2SiO4 and ABC dry powder was more effective and less consumed as compared to commercial mono-ammonium phosphate powder (Class B only). This study demonstrates the efficacy of nCa2SiO4 to improve the performance of dry chemical-based fire extinguishers.

Toward better Halon substitutes: Effects of H content on pyrolytic and fire-suppressing mechanisms of ozone-friendly fluorinated alkanes

Halon extinguishants have been prohibited due to the caused damages to the stratospheric ozone layer. For Halon replacement, ozone-friendly fluorinated alkanes are used as transitional Halon substitutes. In order to unravel the relationship between chemical structures and fire-extinguishing performance of fluoroalkane agents, we investigated the effects of hydrogen content on pyrolytic and fire-extinguishing mechanisms of fluoroalkanes including HFC-236fa (CF3CH2CF3), HFC-227ea (CF3CHFCF3) and PFC-218 (CF3CF2CF3), which may provide some guidance on efficient exploration of new substitutes for Halon extinguishant. Both the experimental and theoretical methods were employed in this study. It was found that the energy barrier of CF3· fire extinguishing free radical generated by the three fluorinated alkanes increases slightly with the increase of H content. The reduction of hydrogen content notably promotes the thermal stability of fluorinated alkanes and the productivity of incombustible pyrolytic products. The HFC-236fa agent exhibits remarkable cooling effect upon the combustion cycle via endothermic pyrolysis, while the PFC-218 agent extinguishes flame predominantly through the dilution effect on the flammable gas. Remarkably, a lower hydrogen content effectively inhibits the production of flammable alkenes, corrosive and toxic pyrolytic products. Although PFC-218 agent exhibits the highest fire-extinguishing concentration (FEC) relative to the other two counterparts, the PFC-218 manifests the subtlest combustion promotion and releases the least corrosive products, which inhibits the suddenly risen temperature in the combustion region and reduces corrosive and poisonous products. These findings provide new understanding and guidance on the molecular designing and screening of environmental-friendly and efficient Halon substitutes.

Experimental study on fire suppression performance of the high pressure water mist in the engine room of an offshore platform

The total flooding application water mist system is a new type of environmentally-friendly fixed extinguishing system. The optimizing design can improve its fire extinguishing performance. At present, the water mist fire extinguishing system in the engine room of the offshore deepwater semi-submersible support platform has not attracted sufficient attention. In this paper, the water mist in the engine room of a deepwater semi-submersible support platform was studied. It contains the effect of water mist on the heat absorption and oxygen insulation of diesel pool fires. The applicable parameters of the water mist fire extinguishing system were also determined. Moreover, based on the shielding of the fire source in the engine room and the different requirements for water mist extinguishing parameters, a hierarchical multi-parameter combined high-pressure water mist fire extinguishing system was proposed. In the full-scale experimental engine room model, according to the fire extinguishing experiments for diesel pool fires with different areas, this kind of hierarchical multi-parameter water mist system is very effective on shielded and non-shielded fires. In addition, it is still effective even in a non-closed environment coupled with smoke exhausting.

Preparation and properties of a new core–shell-modified gel dry-water powder

To improve the spray fire extinguishing performance of magnesium-hydroxide gel dry-water powder, this paper studied the preparation speed, material mass ratio, fluidity, bulk density, pressure resistance, and fire extinguishing performances of modified dry-water powders. A pure-water dry-water powder was modified by applying an effective extinguishing component, magnesium hydroxide, and a coagulant, Gellan gum. The preparation process parameters of the pure-water dry-water powder system were optimized. The results showed that the optimal process parameters for the preparation of dry-water powder were a rotation speed of 4000 rpm, an SiO2:H2O ratio of 9:100, and a stirring time of 3 min. The resting angle of magnesium-hydroxide gel dry-water powder was below 28°, with good fluidity. The bulk density of the dry-water powder was lower than that of the BC-class dry powder extinguishing agent, and the bulk density of the magnesium-hydroxide gel dry-water powder was 0.467 g·mL−1. With the increase in pressure, the damage rate of the dry-water powder increased. The addition of magnesium hydroxide and Gellan gum significantly improved the pressure resistance of the dry-water powder. At a pressure of 1.4 MPa, the magnesium-hydroxide gel dry-water powder was only 11% damaged. The performance of the magnesium-hydroxide gel dry-water powder was improved by 37.21% compared with the average cooling rate of the BC-class dry powder extinguishing agent used as a control fire extinguishing group. The dry-water powders produced by modifying the dry-water powders with magnesium hydroxide and Gellan gum could withstand higher driving pressures, and they had improved powder diffusion, reduced powder charge volume, and increased fire extinguishing properties compared with those of the other dry-water powders.

Preparation and fire extinguishing mechanism of core-shell solid-liquid composite powder containing ammonium dihydrogen phosphate

A solid-liquid composite powder containing core-shell structure is created under the guidance of theoretical level. Among them, the factors affecting preparation are attributed to stirring speed, solid-liquid mass ratio, stirring time and additive concentration. The results of reduced-size fire chamber indicate that the core-shell structured powder containing NH4H2PO4 (WS-2) can suppress diesel flame more effectively than commercial dry powder (CDP) and common core-shell structured powder (WS-1). Besides, WS-2 shows the highest degree of temperature drop, which is 21.14% and 39.82% higher than CDP and WS-1, respectively. Combined with the results of Thermogravimetric analyzer (TGA) and Fourier transform infrared absorption spectroscopy (FTIR), it can be inferred that WS-2 fully embodies multiple inhibitory effects such as isolation, cooling, asphyxiation and chemical suppression. Ultimately, the excellent fire extinguishing performance brought by its unique structure is demonstrated. This study is of great significance for the determination of technological parameters and application of core-shell powders.

Synthesis and Characteristics of a pH-Sensitive Sol-Gel Transition Colloid for Coal Fire Extinguishing.

Coal fires, most of which are triggered by the spontaneous combustion of coal, cause a huge waste of resources and release poisonous and harmful substances into the environment, seriously threatening the safety of industrial production. Gel flame retardant plays a core role in coal fire prevention and extinguishing. Most gel flame retardants used in coal fires possess good sealing and oxygen isolation properties, but it is difficult for them to flow deep into fire areas due to their low fluidity. Some fire extinguishing agents with good fluidity lack leak-blocking performance. In order to simultaneously improve the fluidity, leakage sealing, and oxygen isolation effects of coal fire extinguishing colloids, a novel, pH-sensitive, sol-gel transition colloid was prepared using low methoxyl pectin (LMP), calcium bentonite (Ca-Bt), sodium bentonite (Na-Bt), and water as the main components. When the initial sol-state colloid absorbed acid gas products from coal combustion, the pH value decreased and a large amount of Ca2+ in Ca-Bt precipitated, thus immediately growing calcium bridges with LMP molecules that formed a three-dimensional network structure for gelation. The optimum ratio of the new colloid was determined through X-ray diffraction, tube inversion, shock shear-temperature scanning, and genetic algorithm. By testing the fire extinguishing performance of the colloid, the findings proved that the product had good oxygen isolation performance, strong adhesion ability, high thermal stability, and strong inhibition effects on coal combustion.

Study on fire extinguishing performance of different foam extinguishing agents in diesel pool fire

The physical properties and fire extinguishing performance in diesel fire of aqueous film-forming foam (AFFF) and protein foam (PF) were studied, and the fire extinguishing mechanism of different foams were also analyzed. The results show that 6%AFFF and 6%PF have better performance than that of 3%AFFF and 3%PF, respectively, and AFFF possess higher expansion ratio, 25% drainage time and surface tension than PF at the same concentration. The fire extinguishing test show that the extinguishing performance of foam enhanced with the increase of gas-liquid ratio firstly, and decreased subsequently. The best fire extinguishing performance were achieved when gas-liquid ratio of 6%AFFF and 6%PF were 17 and 20, and the extinguishing agent dosage were 229 ml and 260 ml, respectively. Compared with PF, the fire extinguishing time and agent dosage of AFFF are reduced by 10% and 6.15% respectively at gas-liquid ratio of 20. Besides, AFFF can form more dense, stable and high-multiple foam cover layer, endow it with better fire extinguishing performance than PF. However, PF can reduce the temperature around the oil pool more quickly, showing better cooling effect than AFFF.