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  • Smart firefighting construction in China: Status, problems, and reflections
    Fire Mater. (IF 1.173) Pub Date : 2020-01-22
    Zhang Guowei; Yan Su; Zhu Guoqing; Feng Pengyue; Jia Boyan

    “Smart firefighting” construction as a part of the “smart city” has been a concern of the public security and fire agencies at all levels. In this study, the status, problems, and reflections of “smart firefighting” construction in China are discussed. A recent survey indicates that China has launched its smart firefighting construction and initially created a new perspective on its regional smart firefighting work based on three main aspects: intelligent disaster perception by Internet of Things (IoT) construction, intelligent disaster prevention by big data construction, and intelligent disaster disposal by emergency rescue platform construction. However, the current smart firefighting construction in China still has some prominent problems such as the data interconnectivity and normalized management of various platforms, the extensibility of smart firefighting platforms, and the intelligent level of smart firefighting researches, which need to be solved urgently. Therefore, we argue that smart firefighting construction in China should establish data interconnectivity, industrial normalized management, 2D/3D geographic information interaction and extension, high‐integration fire protection theory, and many other aspects in the near future and truly realize firefighting visualization and efficient data applications for 4D time space. This study could provide valuable reference for smart firefighting and smart city construction.

    更新日期:2020-01-23
  • Issue Information
    Fire Mater. (IF 1.173) Pub Date : 2020-01-14

    No abstract is available for this article.

    更新日期:2020-01-14
  • Reconstruction of Grenfell Tower fire. Part 1: Lessons from observations and determination of work hypotheses
    Fire Mater. (IF 1.173) Pub Date : 2019-11-17
    Eric Guillaume; Virginie Dréan; Bertrand Girardin; Faiz Benameur; Talal Fateh

    The Grenfell Tower fire occurred on 14 June 2017, killing 72 people. The pattern and speed of vertical and horizontal fire spread characterize this catastrophic event. Plentiful video and photographic data of the fire spread available has been carefully verified and concatenated into a database. The verified data have been superimposed on a projection of the Grenfell Tower in order to track the development of the fire. The surface that is unburnt, burning, or extinguished, as well as the presence of internal fire at any given location, is thus recorded for the duration of the fire. An analysis of the results showed that the initial vertical propagation can be divided into three phases. After the façade ignited at the fourth floor, vertical propagation over time is linear, with a vertical fire spread rate of around 3.5 m/min until the fire reached the sixth floor. Then fire propagation decelerated. Finally, fire spread accelerated with a power four dependence. The maximum vertical fire spread rate was around 8 m/min as the fire reached the crown at the top of the building. Horizontal spread proved to be greatest at the level of the crown (0.293 ± 0.005 m/min). There is a linear relationship between speed of horizontal fire spread and height. These correlations and observations yield important conclusions, and eight different hypotheses capable of explaining the global behaviour of the fire are suggested.

    更新日期:2020-01-14
  • Reconstruction of Grenfell Tower fire. Part 2: A numerical investigation of the fire propagation and behaviour from the initial apartment to the façade
    Fire Mater. (IF 1.173) Pub Date : 2019-11-17
    Eric Guillaume; Virginie Dréan; Bertrand Girardin; Maxime Koohkan; Talal Fateh

    The dramatic event of the Grenfell Tower in 2017 reminds the importance of addressing fire issues as a whole and clearly highlighted one of the major roles played by the façade as fire propagation vector. To understand and analyse this disaster, numerical simulation allows particular phenomena to be evaluated more easily. The numerical model addressed for the fire behaviour of the façade system was developed using a multiscale approach and validated at different scales. In this paper, the fire behaviour of the façade and of its window frames is addressed. A computational fluid dynamics (CFD) model is used to investigate the fire spread from the initial apartment to the overall façade with different scenarios for the fire source and ventilation. Fire propagation through windows to the façade and to upper apartments is addressed. General curves representing the re‐entry of flames into upper apartment are extracted from simulations. The numerical results are validated by comparison with observations from videos and pictures of the real fire. Numerical results show that whatever the initial fire location and ventilation conditions, even if the fire source is of hundreds kilowatts, it is enough to ignite the adjacent element early and to the appearance of external flames shortly after.

    更新日期:2020-01-14
  • Reconstruction of Grenfell Tower fire. Part 3—Numerical simulation of the Grenfell Tower disaster: Contribution to the understanding of the fire propagation and behaviour during the vertical fire spread
    Fire Mater. (IF 1.173) Pub Date : 2019-11-17
    Eric Guillaume; Virginie Dréan; Bertrand Girardin; Faiz Benameur; Maxime Koohkan; Talal Fateh

    The dramatic event of the Grenfell Tower (June 2017), involving a combustible façade system, has raised concerns regarding the fire risk that these systems address. Indeed, as façades are complex systems, it is not straightforward to assess which part of the system is involved in the global fire behaviour. Understanding such façade fires is thus very complex as it depends on a combination of various products and system characteristics, including window frames or air gap or cavity barriers. Fire development inside the initial apartment was investigated using an appropriate CFD model with different scenarios for the fire source and ventilation conditions in a previous study. Fire propagation through the window to the external façade and to higher apartments was modelled and validated against visual observations. This paper describes CFD modelling of the complete Grenfell tower facade, and investigates vertical fire spread behaviour over the full height façade from the initial apartment. Contributions from the combustion of all the apartments' furniture, depending on window failure, and architectural details of the refurbished façade are considered in the numerical model. The modelling results are validated by comparison with photographic and video observations of the real fire.

    更新日期:2020-01-14
  • Melt dripping behavior in the process of flame spread over energized electrical wire at different pressures
    Fire Mater. (IF 1.173) Pub Date : 2019-10-16
    Zhi Wang; Ruichao Wei; Junjiang He; Jian Wang

    Melt dripping of polymer insulation in electrical wires is impacted by some factors, such as ambient pressure and electric current. The motivation of this paper is to investigate and discuss the effect of these factors on melt dripping characteristics in the process of flame spread over electrical wire. The results show that the number of dripping times and dripping frequency generally increase with ambient pressure reduced. No dripping phenomenon occurs when the ambient pressure is below 40 kPa at any electric current or is above 70 kPa without electric current applied. There is a good parabolic correlation between the ambient pressure and dripping frequency. The equilibrium temperature of conductor resulted by electric current increases with electric current. A critical electric current found to divide the temperature rate into two regimes is about 8 A. The dripping period and dripping frequency depend on the electric current. The dripping frequency fits well with electric current using a power‐law function. The numerical data are consistent with the experimental data. Besides, the decrease in dripping frequency is greater with ambient pressure at reduced electric current, whereas at larger electric current, the electric current, rather than the ambient pressure, dominates the increased dripping frequency.

    更新日期:2020-01-14
  • Study of smoke movement characteristics in tunnel fires in high‐altitude areas
    Fire Mater. (IF 1.173) Pub Date : 2019-11-24
    Guanfeng Yan; Mingnian Wang; Li Yu; Yuan Tian; Xiaohan Guo

    Understanding smoke temperature distributions and transport characteristics is of great importance to control and exhaust thermal‐driven smoke. However, previous studies have focused on this problem in plain areas, whereas ambient pressure decreases as elevation increases. This study investigates the influence of ambient pressure on the hot gas temperature distribution and movement characteristics in a tunnel fire. A series of numerical simulations are carried out in a vehicle tunnel with various heat release rates (HRRs) and ambient pressures. The results show that the maximum temperature and longitudinal temperature distribution under the tunnel ceiling increase with decreasing ambient pressure due to less heat loss caused by lower air density. In addition, the vertical temperatures of the smoke are slightly higher under lower ambient pressure, and this phenomenon makes the smoke spread slightly faster while the smoke layer thickness remains nearly the same under different ambient pressures. The results can provide a reference for tunnel lining design and ventilation arrangements in high‐altitude areas.

    更新日期:2020-01-14
  • Development and performance study of a novel physicochemical composite inhibitor for the prevention of coal gangue spontaneous combustion
    Fire Mater. (IF 1.173) Pub Date : 2019-11-08
    Zhian Huang; Tian Le; Yinghua Zhang; Yukun Gao; Jinyang Li; Ziyou Li; Zhenzhen Ma

    To overcome the short inhibition life of currently available inhibitors, a high polymer nanocomposite inhibitor was developed. The spontaneous combustion characteristics of coal gangue from the Yangquan mining area were studied through proximate analysis, scanning electron microscope/energy dispersive spectrometer (SEM/EDS), and thermogravimetric analysis. As a result, the coal gangue was found to be prone to spontaneous combustion. Temperature‐programmed oxidation experiments showed that the average inhibition rates of Ca (OH)2 or polyacrylamide (PAM) were 30.99% and 30.95%, respectively. During testing, when the temperature of the coal gangue exceeded 160°C, the CO production and oxygen consumption rate of the sample with PAM increased dramatically, proving that the PAM inhibition effect was short‐lived with elevating temperature, whereas the inhibition rate of polyacrylamide/montmorillonite (PAM/MMT) was significantly increased to 47.70%. In addition, the CO production and oxygen consumption rates were significantly reduced in the late oxidation period, proving that the addition of MMT was able to effectively improve the high‐temperature resistance of the PAM. Different concentrations of PAM/MMT were compounded with Ca (OH)2, further improving the inhibition effect of the treatment. The inhibition effect of the PAM/MMT 3%‐Ca (OH)2 20% composite inhibitor was the best in the study, with an inhibition rate of 83.15%.

    更新日期:2020-01-14
  • Effects of different charging and discharging modes on thermal behavior of lithium ion batteries
    Fire Mater. (IF 1.173) Pub Date : 2019-11-21
    Yun Yang; Zhirong Wang; Juncheng Jiang; Huan Bian; Ning Mao; Linsheng Guo

    The heat release law of lithium ion battery during different cycles of charging‐discharging rate was studied by the LAND testing device. Studies have shown that: When charging at 0.5C and discharge cycles at 0.5C, 1C, 2C, and 3C, respectively, the battery cycle heat dissipation increases with the increase of the discharge rate, and the temperature rise ratio of the battery after the 3C cycle is 0.5C, 1C, 2C is higher by 30.8 °C, 21.4 °C, and 9 °C; 0.5C, 1C, 2C, 3C rechargeable battery temperature rise after 1C discharge and 0.5C, 1C, 2C, 3C charge cycles, respectively. The heights are 13.8 °C, 18.1 °C, 37.6 °C, and 44.3 °C, respectively; when the battery is cycled at a 3C charging‐discharging rate, the battery voltage suddenly changes to 0 V after the 2nd cycle; when the charge current and discharge current are relatively small, the heat generated during low‐rate charging high‐rate discharge cycles is larger, and when the charge current and the discharge current are relatively large, the heat generated at the low‐rate charging high rate discharge cycle is smaller than the high‐rate charging low‐rate discharge cycle. The research obtained the heat dissipation data of lithium‐ion batteries under different charging‐discharging rates, which provided an important basis for the safe operation of lithium‐ion batteries.

    更新日期:2020-01-14
  • Treatments and modification to improve the reaction to fire of wood and wood based products—An overview
    Fire Mater. (IF 1.173) Pub Date : 2019-11-17
    Carmen‐Mihaela Popescu; Alexander Pfriem

    Wood and wood‐based products are widely used for structural building elements, but due to their composition, they are susceptible of combusting if exposed to fire. Fire safety is an important issue of building safety, especially when the building's fire load contents enhance the risks of fire spread. Therefore, the involved materials are very important to address the fire safety requirements. When existing timber structures are involved, the most usual way to improve its reaction to fire is to treat wood with fire retardant materials.

    更新日期:2020-01-14
  • Comparative study of the fire protection performance and thermal stability of intumescent fire‐retardant coatings filled with three types of clay nano‐fillers
    Fire Mater. (IF 1.173) Pub Date : 2019-12-02
    Zhisheng Xu; Huan Zhou; Long Yan; Hongyu Jia

    The fire protection and thermal stability properties of intumescent fire‐retardant coatings filled with three various clay nano‐fillers (layer double hydroxide [LDH], montmorillonite [MMT], and sepiolite) were compared by fire protection tests and thermo‐gravimetric analysis. The fire protection tests show that the incorporation of three fillers improves the fire protection properties of the intumescent fire‐retardant coatings and the addition of 1 wt% sepiolite exhibits the lowest flame spread rating of 9.9 and equilibrium backside temperature of 164.5°C at 900 seconds. TG analysis shows that the incorporation of nano‐fillers imparts a considerable enhancement of thermal stability and char formation to the intumescent coatings. Especially, the coating with 1 wt% sepiolite acquires the highest residual weight of 34.2% among the samples. Char residue analysis presents that the introduction of clay nano‐fillers plays a positive role in enhancing the compactness and anti‐oxidation ability of the char residues, and this positive effect as well as the flame‐retardant efficiency depends on the types of clay nano‐fillers. The three types of layered clay nano‐fillers exhibit synergistic flame‐retardant effectiveness in the order of sepiolite > MMT > LDH.

    更新日期:2020-01-14
  • Efficiency of sustained burning of layered leaf fuels under external radiant heat flux
    Fire Mater. (IF 1.173) Pub Date : 2019-12-01
    Hai‐Hui Wang; Feng‐Qi Yao; Jun‐Jun Tao; Feng Zhu

    Efficiency of energy release by burning of layered leaf fuels under external radiant heat flux was studied using a cone calorimeter. By performing the ignition and sustained burning measurements with coniferous and broadleaf plants, a method was developed to determine the combustion efficiency during sustained burning χc. Experimental results showed that at the same radiant heat flux, an increase in the sample mass (density) leads to substantial decrease in χc followed by a level‐off, and the increase in leaf moisture content results in significant reduction of χc. Analysis indicated that χc is essentially independent to the sample mass when a sample is constituted by three layers. By defining a ratio of the amount of CO produced to that of O2 consumed during measurement ϕCO/O2, χc was found to be well correlated by ϕCO/O2 with the form χc = 0.2166ln[0.4655/(ϕCO/O2 − 0.03177)], thereby highlighting that energy release efficiency of a sample mainly relies on the extent of O2 consumed to convert into CO. The parameter χc acts as an indicator to reveal the combustion states of a fuel during testing, and the parameter ϕCO/O2 can be used as an index to evaluate the capacity of leaf fuels to emit toxic gases in specific fire scenarios.

    更新日期:2020-01-14
  • New approaches to determine the interface height of fire smoke based on a three‐layer zone model and its verification in large confined space
    Fire Mater. (IF 1.173) Pub Date : 2019-12-04
    Ying Zhang; Zhiyang Liu; Yifan Lin; Ming Fu; Yue Chen

    Large confined space has high incidence of fires, which seriously threatens the safety of people working there. Understanding the distribution of smoke in such large space is critical to fire development prediction and smoke control. Three improved methods for the stratification interface prediction of fire smoke are developed, including of improved intra‐variance, integral ratio and N‐percentage methods. In these methods, the interface height is determined by the vertical temperature distribution based on a three‐layer smoke zone model, which is an improvement of a two‐layer zone model. Thereafter, the three improved methods are applied to several typical fire cases simulated CFD to predict the smoke interface, and their applicability and reliability are verified by comparison of the smoke stratification results with the filed simulation results. Results show that the three improved methods can effectively determine the location of the three‐layer zone model's interface, and they have the ability to predict smoke interface for fires with different fire source types and ventilation conditions.

    更新日期:2020-01-14
  • Research on the plume shape under optimal wind environment to prevent the smoke backflow and combustion gains in utility tunnel
    Fire Mater. (IF 1.173) Pub Date : 2019-12-02
    Yuan Zheng; Kai Ye; Hong Liu; Fei Peng; Bei Cao; Yubiao Huang; Lizhong Yang

    The utility tunnels have been applied extensively to run the various pipelines in the urban areas such as the gas pipeline, electrical power cables, and the likes. Contradicting with the rapid development of the utility tunnels is the ambiguity of the fire protection code to which one critical point is whether to ventilate in the fire accident, which is hampered by the effect of wind on the combustion gain. Therefore, this paper combines the plume function with the backlayering length and critical backflow velocity to explore the plume shape, optimize the ventilation environment, and decrease its combustion gain in which shows three key features that include the concavity and convexity characteristics, instability of plume, and the balance feature. Moreover, through their derived five plume shape constraints, we acquire the optimal wind environment. Furthermore, we found that the expected length is 0.12 in optimal condition when the original critical velocity is larger than 0.43, and the other cases are 0.05 for expected length. Meanwhile, the ventilation velocity needs to be increased three to seven times. The study provides new insight into the plume flow under the wind environment and would accelerate the formalization of fire protection design for utility tunnel.

    更新日期:2020-01-14
  • Experimental study on the vertical temperature distribution of window ejected fire from an enclosure with adjacent side walls
    Fire Mater. (IF 1.173) Pub Date : 2019-12-03
    Tong Xu; Qing He; Fei Tang; Peng Lei; Huanping Pang

    This paper measured and analyzed the vertical temperature profile of window ejected fire from a cubic enclosure with the effect of adjacent parallel sidewalls. A cubic enclosure size is 0.4 m (height) × 0.4 m (width) × 0.4 m (length). And two side walls were fixed on the both side of the compartment openings, its distance can be changed. K‐Type thermocouples (T1‐T4) were installed in the inside compartment (inner and outer corner), the vertical position along the façade wall and the center of side wall, respectively. It is found that the side wall distance was independent of the temperature distribution inside the enclosure when the opening size changed from 0.2 m to infinity, and the vertical temperature profile along the side wall significantly increased with the decrease of the separation distances of two sidewalls. A dimensionless correlation was proposed to describe the vertical temperature along the facade wall for various side wall separation dimensions. The new findings and the proposed dimensionless correlation provide basic knowledge for describing vertical temperature along the facade wall.

    更新日期:2020-01-14
  • Thermal sensor performance and fire characterisation during short duration engulfment tests
    Fire Mater. (IF 1.173) Pub Date : 2020-01-13
    Shelley Kemp; Gary Proulx; Margaret Auerbach; Michael Grady; Roger Parry; Martin Camenzind

    A small‐scale reproduction of the ISO 13506‐1 thermal manikin was constructed to enable the assessment of manikin sensor performance, the partitioning of energy, and the variability of the fire generated during short duration heat and flame engulfment tests. The cylindrical test apparatus simultaneously housed four total heat flux (THF) sensors, one radiant heat flux sensor, and three manikin sensors. Calibrated manikin sensors were provided by nine laboratories and were categorised as buried thermocouple, copper‐based, or surface‐mounted thermocouple sensors. The test apparatus was exposed to fire generated by four propane torches for three exposure durations. All sensors presented similar profiles in net heat flux over time, which could be divided into four distinct phases: transient increase, pseudo‐steady state, transient decrease, and post‐exposure. Over pseudo‐steady state, the mean THF over all exposure durations was 88 ± 8 kW/m2, and the ratio of convective to radiant energy was approximately 50:50, but highly variable. For a 4‐second exposure, manikin sensors from five laboratories had a bias in heat flux greater than ± 5% during pseudo‐steady state when compared with the THF sensors. This bias can primarily be attributed to the sensitivity of the manikin sensors to convective heat or heat loss due to sensor design.

    更新日期:2020-01-14
  • Rectification of “restrained vs unrestrained”
    Fire Mater. (IF 1.173) Pub Date : 2020-01-10
    Kevin LaMalva; Luke Bisby; John Gales; Thomas Gernay; Elie Hantouche; Cliff Jones; Ali Morovat; Robert Solomon; Jose Torero

    For furnace testing of fire‐resistant floor and roof assemblies in the United States, the ASTM E 119 standard (and similarly the UL 263 standard) permits two classifications for boundary conditions: “restrained” and “unrestrained.” When incorporating tested assemblies into an actual structural system, the designer, oftentimes a fire protection or structural engineer, must judge whether a “restrained” or “unrestrained” classification is appropriate for the application. It is critical that this assumption be carefully considered and understood, as many qualified listings permit a lesser thickness of applied fire protection for steel structures (or less concrete cover for concrete structures) to achieve a certain fire resistance rating if a “restrained” classification is confirmed, as compared with an “unrestrained” classification. The emerging standardization of structural fire engineering practice in the United States will disrupt century‐long norms in the manner to which structural behavior in fire is addressed. For instance, the current edition of the ASCE/SEI 7 standard will greatly impact how designers consider restraint. Accordingly, this paper serves as an exposé of the “restrained vs unrestrained” paradigm in terms of its paradoxical nature and its controversial impact on the industry. More importantly, potential solutions toward industry rectification are provided for the first time in a contemporary study of this paradigm.

    更新日期:2020-01-11
  • Study of flame‐retarded silicone rubber with ceramifiable property
    Fire Mater. (IF 1.173) Pub Date : 2019-12-30
    Zhixi Li; Wenjuan Liang; Yifei Shan; Xiaoxiao Wang; Kun Yang; Yongyan Cui

    Fire‐resistant ceramifiable silicone rubber composites with excellent comprehensive property were prepared in this paper. Silicone rubber was used as the base polymer, aluminum hydroxide, magnesium hydroxide, zinc borate, and glass frits were additives. The flammability and thermal stability properties, essentially focusing on the use of the limiting oxygen index and thermogravimetric analysis, were all studied. Besides, the ceramic residues were also studied by mechanical testing, scanning electron microscopy, and X‐ray diffraction. The ceramifying silicone rubber could achieve a limiting oxygen index value of 34.8%, and the flexural strength of ceramic residues formed at 800°C was 9.7 MPa. The residue of composites was approximately 58.6% at 700°C, which is significantly higher than that of neat silicone rubber. The scanning electron microscopy analysis depicted that a dense structure was formed as formed.

    更新日期:2019-12-30
  • Flame‐retardant compounds for polymeric materials from an abundantly available, renewable biosource, castor oil
    Fire Mater. (IF 1.173) Pub Date : 2019-12-26
    Bob A. Howell; Eric A. Ostrander

    Castor oil is a triglyceride extracted from the seed (castor bean) of the castor plant. This plant will thrive on relatively poor soil and in an arid climate. The oil is nonedible but is produced annually in large volume to be converted to biodiesel (largely for the European market). The oil contains both unsaturation and hydroxyl functionality that may be utilized for conversion to flame retarding materials. A series of phosphorus esters has been generated from castor oil. All display good flame retardancy in the diglycidyl ether of bisphenol A (DGEBA) epoxy resin. Introduction of bromine at the double bond generally enhances the flame retardancy of these esters.

    更新日期:2019-12-27
  • Effects of passenger blockage on smoke flow properties in longitudinally ventilated tunnel fires
    Fire Mater. (IF 1.173) Pub Date : 2019-12-26
    Yan Wang; Fan Wu; Peihong Wu

    This paper investigates the effects of passenger blockage on smoke flow properties in longitudinally ventilated tunnel fires. A series of numerical simulations were conducted in a 1/5 small‐scale tunnel with the different heat release rates (50‐100 kW), longitudinal ventilation velocities (0.5‐1 m/s), passenger blockage lengths (2‐6 m), and ratios (0.17‐0.267). The typical smoke flow properties in different tunnel fire scenarios are analyzed, and the results show that under the same heat release rate and longitudinal ventilation velocity, the smoke back‐layering length, maximum smoke temperature, and downstream smoke layer height decrease with increasing passenger blockage length or ratio. The Li correlations can well predict the smoke back‐layering length and maximum smoke temperature in tunnel fire scenarios without the passenger blockage. When the passenger blockage exists, the modified local ventilation velocity that takes the blockage length and ratio into account has been proposed to correct the Li correlations. The smoke back‐layering length and maximum smoke temperature with the different blockage lengths and ratios can be predicted by the modified correlations, which are shown to well reproduce the simulation results.

    更新日期:2019-12-27
  • Thermal decomposition of ammonium nitrate
    Fire Mater. (IF 1.173) Pub Date : 2019-12-26
    Vytenis Babrauskas; David Leggett

    The thermal decomposition reactions of ammonium nitrate (AN) are reviewed. Both neat AN and AN containing various contaminants are examined, however quantitative kinetics results are not encompassed. Also not included is the performance of AN as the oxidizer in rocket propellants or in explosives such as ANFO. The review is intended to be the most comprehensive review of decomposition reactions of AN since Berthelot's treatise of 1892. Despite hundreds of papers on the topic that have appeared in the intervening years, understanding of decomposition mechanisms remains only modestly more complete than it was in Berthelot's day. However, some additional reaction steps and mechanisms have been identified and these are discussed. Explosions of AN most commonly involve fire as the proximate cause, yet chemical‐mechanism research on the topic is nil. A modest number of studies have explored the potentiation of AN decomposition by organic contaminants. These have, thus far, not produced guidance useful for promoting of safety from fire‐related causes. Contamination from inorganic sources, notably chlorides is better understood and some mechanisms have been studied. The UN classification of AN as an oxidizer, instead of as an explosive, should not be interpreted literally, since AN has been associated with numerous detonation disasters.

    更新日期:2019-12-27
  • Halogen‐free flame‐retardant flexible polyurethane for textile coating: Preparation and characterisation
    Fire Mater. (IF 1.173) Pub Date : 2019-12-21
    Tung Ngoc Nguyen; Hung Tuan Trinh; Lien Hoang Sam; Trung Quang Nguyen; Giang Truong Le

    A type of flexible polyurethane (FPU) based on renewable‐sourced polyol was prepared and then modified with halogen‐free flame retardants, namely, alumina trihydrate (ATH) and triphenyl phosphate (TPhP), to further increase its flame‐resistant properties. The optimum loading for additives was determined based on analysing the changes in physicomechanical properties, thermal properties, and flame‐retardant behaviours of modified FPU materials. An FPU‐coated textile was then prepared; its smoke‐generating behaviours and flammability were investigated in comparison with pristine fabric, pristine FPU, and respective modified FPU. The results confirmed good synergistic effect between ATH and TPhP, which helped increasing flame‐resistant properties of applied materials, while also maintained reasonable flexibility for fabric‐coating applications. However, the usage of modified FPU as coating material also proved to cause more toxic smoke emissions during the short burning duration of coated‐fabric, an issue that needed to be investigated more thoroughly in order to guarantee the safety of people during catastrophic events.

    更新日期:2019-12-21
  • Effect of passive protection on fire propagation of electrical cables
    Fire Mater. (IF 1.173) Pub Date : 2019-12-20
    Dong Zeng; Yi Wang; Daniel Boardman

    Flame retardant cable coatings are applied to grouped electrical cables as a passive protection means to reduce the fire hazard. This work studied the flammability of cable coatings and developed a fire test method to evaluate the fire propagation propensity of grouped cables protected by cable coatings. Firstly, ignition tests of 12 cable coatings were conducted and showed that all cable coatings are ignitable. Secondly, three selected cable coatings and a cable bandage, as an alternative passive protection method, were evaluated along with two types of electrical cables in ASTM E‐2058/ISO 12136 by measuring the fire propagation index (FPI). The FPI values of coated cables do not demonstrate a monotonous change relative to the FPI of uncoated cables, and the FPI trend is cable dependent. Thirdly, two selected cable coatings and a cable bandage were further examined in the 2.4‐m parallel panel fire test (PPT) along with an electrical cable with an FPI value of 30 (m/s1/2)/(kW/m)2/3. The cables coated by both tested cable coatings showed fire propagation while the bandaged cables did not propagate. The consistent fire propagation propensities between the PPT and small‐scale fire tests support using the FPA tests to examine the flammability of cable coatings.

    更新日期:2019-12-21
  • Research on a noble extinguish material for the underground fire prevention
    Fire Mater. (IF 1.173) Pub Date : 2019-12-20
    Xin‐Xiao Lu; Yu Han; Xue Xue; De‐Ming Wang

    The three‐phase foam consisted of solid, liquid and gas is regarded as a highly effective measure for the underground mine fire prevention. In this study, the three‐phase foam technology is introduced and a visualization platform is established to exhibit the foam flow in a physical goaf. The diffusion rule and extinguishing performance for three‐phase foam are researched. Test results show that the three‐phase foam has a superior heat resistance than expansion foam in the top goaf. The coal heating rate is postponed after the three‐phase foam processing and the active functional groups are suppressed effectively. Increasing the foam expansion ratio is adverse to the three‐phase foam stability. The field application of three‐phase foam was evaluated via the practical extinguishment effect. The marked reduction in the sealed zone temperature and CO concentration proved that the proposed three‐phase foam technology was effective on controlling the concealed goaf fire.

    更新日期:2019-12-20
  • Thermal runaway hazard characteristics and influencing factors of Li‐ion battery packs under high‐rate charge condition
    Fire Mater. (IF 1.173) Pub Date : 2019-12-18
    Huan Bian; Zhirong Wang; Juncheng Jiang; Yun Yang; Hao Wang; Shichen Chen

    In a special environment such as a high‐rate charge or discharge one, the positive and negative electrode materials of a lithium ion battery may undergo a chemical exothermic reaction with an electrolyte and a binder and release a large amount of heat to cause thermal runaway, resulting in harmful consequences. In this paper, high‐rate charging experiments of different types of 18650 Li‐ion battery packs were performed to study the behavior and influencing factors of Li‐ion battery packs when thermal runaway occurred. Automatic test equipment with battery comprehensive parameters was adopted, and a Li‐ion battery thermal runaway test device was designed and used to test a series of Li‐ion battery packs under high‐rate charging conditions. The series of tests were conducted under different conditions of different cell spacing, pick‐up point positions and connection modes. Results showed that under the above three different conditions, the initial time and the initial temperature of the thermal runaway of the Li‐ion battery packs, the maximum temperature of thermal runaway and the position where the first thermal runaway battery occurred showed some regular changes.

    更新日期:2019-12-19
  • Material properties of clay and lime plaster for structural fire design
    Fire Mater. (IF 1.173) Pub Date : 2019-12-18
    Liblik Johanna; Küppers Judith; Just Alar; Maaten Birgit; Pajusaar Siim

    Clay and lime plaster are traditional surface finish materials used on historic timber walls and ceilings. Today, hardly any fire technical properties or design parameters exist that consider such plasters as fire protection materials for timber structures. This hinders the fire assessment of existing building structures and disadvantages their use in modern design solutions where healthy and sustainable materials are increasingly favoured. This research follows the safety philosophy of EN 1995‐1‐2 to describe the fire protection ability of plasters. This paper investigates the temperature‐dependent thermal properties of historic plasters by presenting series of material‐specific tests and furnace tests carried out under standard fire exposure conditions. Experimental studies are supported by numerical heat transfer simulations. Results demonstrate particularities between the fire protection ability of clay and lime plaster, however, highlight the need for further investigations in terms of their thermophysical performance and standardisation at the European level. Design parameters are presented and discussed in future perspective. This work demonstrates a basic research to plan and design full‐scale fire tests according to EN 13381‐7:2019.

    更新日期:2019-12-19
  • Effect of water erosion on flame retardancy of high‐impact polystyrene/magnesium hydroxide composite and its mode of action
    Fire Mater. (IF 1.173) Pub Date : 2019-12-15
    Jichun Liu; Hang Li; Haibo Chang; Yunpeng He; Anyang Zhong; Sai Wu; Bingli Pan

    High‐impact polystyrene (HIPS) flame retarded by magnesium hydroxide (MH) was treated in water at different conditions. The effect of water erosion on flame retardancy of the HIPS/MH composite and its mode of action was investigated by various means. The results indicate that both limiting oxygen index value and UL‐94 rating of the HIPS/MH composite decrease observably after water erosion. The average heat release rate, average mass loss rate, total heat release, and total smoke release of the composite all increase remarkably after water erosion. The MH content in the surface layer of the HIPS/MH composite reduces, and the surface of this composite becomes rough and porous after erosion. The water‐eroded composite shows a loose and discrete surface morphology after subjected to fire, which favors heat transfer and mass exchange between flame area and the underlying polymers. Consequently, both flame retardancy and smoke suppression of the polymer composite decrease significantly. The decrease in flame retardancy occurs in condensed phase. The result of this work has provided a basis for further investigations to prevent this detrimental effect induced by water erosion.

    更新日期:2019-12-17
  • Flame extension and the near field under the ceiling for travelling fires inside large compartments
    Fire Mater. (IF 1.173) Pub Date : 2019-12-13
    Mohammad Heidari; Panagiotis Kotsovinos; Guillermo Rein

    Structures need to be designed to maintain their stability in the event of a fire. The travelling fire methodology (TFM) defines the thermal boundary condition for structural design of large compartments of fires that do not flashover, considering near field and far field regions. TFM assumes a near field temperature of 1200°C, where the flame is impinging on the ceiling without any extension and gives the temperature of the hot gases in the far field from Alpert correlations. This paper revisits the near field assumptions of the TFM and, for the first time, includes horizontal flame extension under the ceiling, which affects the heating exposure of the structural members thus their load‐bearing capacity. It also formulates the thermal boundary condition in terms of heat flux rather than in terms of temperature as it is used in TFM, which allows for a more formal treatment of heat transfer. The Hasemi, Wakamatsu, and Lattimer models of heat flux from flame are investigated for the near field. The methodology is applied to an open‐plan generic office compartment with a floor area of 960 m2 and 3.60 m high with concrete and with protected and unprotected steel structural members. The near field length with flame extension (fTFM) is found to be between 1.5 and 6.5 times longer than without flame extension. The duration of the exposure to peak heat flux depends on the flame length, which is 53 min for fTFM compared with 17 min for TFM, in the case of a slow 5% floor area fire. The peak heat flux is from 112 to 236 kW/m2 for the majority of fire sizes using the Wakamatsu model and from 80 to 120 kW/m2 for the Hasemi and Lattimer models, compared with 215 to 228 kW/m2 for TFM. The results show that for all cases, TFM results in higher structural temperatures compared with different fTFM models (600°C for concrete rebar and 800°C for protected steel beam), except for the Wakamatsu model that for small fires, leads to approximately 20% higher temperatures than TFM. These findings mitigate the uncertainty around the TFM near field model and confirm that it is conservative for calculation of the thermal load on structures. This study contributes to the creation of design tools for better structural fire engineering.

    更新日期:2019-12-13
  • Electrical component ignition in a closed enclosure adjacent to a controlled fire
    Fire Mater. (IF 1.173) Pub Date : 2019-12-10
    Pascal Zavaleta, Olivier Bouygues, Céline Lapuerta

    Electrical cabinet fires are one of the main fire hazards in nuclear power plants (NPPs). The electrical cabinets are often arranged in rows of adjacent cabinets (ACs) in NPPs. So the ability of a cabinet fire to spread to ACs is a major concern for fire safety. This work aims to investigate the impact on the fire spread of the air gap between two electrical cabinets, the electrical component type contained in the AC, and its ventilation mode. For that purpose, a test device composed of two adjacent steel enclosures was designed in order to reproduce at reduced‐scale adjacent electrical cabinets. This study first reveals that the studied electrical component types spontaneously ignited when their temperature and the incident heat flux reach critical ignition values. These ignition criteria are assessed for each component type. The tests also show that the air gap increase slows down the rise of the side wall temperature of the two enclosures, which delays the ignition time of the electrical components. This work finally highlights that the mechanical ventilation of the adjacent enclosure (AE) has an impact on the ignition conditions. In contrast, the natural ventilation as implemented in the AE has a small effect on these conditions.

    更新日期:2019-12-11
  • Apparatus for investigating the burning and dripping of vertically oriented polyurethane foams
    Fire Mater. (IF 1.173) Pub Date : 2019-12-06
    Dennis S. W. Pau, Charles M. Fleischmann, Michael A. Delichatsios

    The burning and dripping behaviour of polyurethane (PU) foam is crucial for upholstered furniture fires due to the melting and dripping behaviour of the foam that results in a pool fire under the furniture, which enhances the combustion. The sample feeding vertical cone is developed to investigate the two‐dimensional small‐scale burning and dripping behaviour of vertically oriented PU foams where a constant irradiance is maintained at the exposed surface by means of automatic sample compensation. Seven different PU foams were investigated and classified as conventional foam or char‐forming foam according to the observed surface phenomena during exposure to heat fluxes. The burning and dripping behaviour is found to depend on the foam density as well as the solid‐phase char formation by the presence of fire retardant additives. The total mass loss rate and the dripping rate increase with higher foam density and with the presence of char formation. In contrary, the vaporisation rate is favoured at lower foam density and with the absence of char formation. Flexible foams of low density without the ability to form char tend to achieve low dripping rate where majority of the mass loss is via vaporisation, contributing directly to the gas‐phase combustion.

    更新日期:2019-12-11
  • Thermal behaviour of laminated bamboo structures under fire conditions
    Fire Mater. (IF 1.173) Pub Date : 2019-12-04
    Ian Pope, Juan P. Hidalgo, Andres Osorio, Cristián Maluk, José L. Torero

    A series of experiments have been conducted to measure the in‐depth heating of laminated bamboo samples subjected to heat fluxes of 5, 10, 30, and 60 kW/m2, either perpendicular or parallel to the grain. These heat fluxes were chosen to induce different phenomena within the material—from inert heating to moisture evaporation, pyrolysis, oxidation, and flaming—so that the effects of these can be isolated and evaluated separately by simple heat‐transfer models. Moisture migration along the fibres becomes a critical factor when bamboo is heated parallel to the grain, resulting in increased convective heat transfer to deeper parts of the material and an accumulation of moisture in depth that accentuates the endothermic plateau in the temperature profiles around 100°C. Average charring rates for 60 minutes of exposure under 60 kW/m2 were 0.74 and 0.70 mm/min for perpendicular and parallel heating, respectively. The thickness of the heated layer was much larger for parallel heating due to moisture migration, which is less significant perpendicular to the grain. Inert heat diffusion is a good approximation at heat fluxes of 5 and 10 kW/m2, but exothermic oxidation reactions become critical above 400°C and must be included in future models.

    更新日期:2019-12-11
  • Evaluation of standard and real fire exposures on thermal response of rail car floor assembly
    Fire Mater. (IF 1.173) Pub Date : 2019-12-02
    Anil Kapahi, Mark McKinnon, Brian Lattimer

    This work developed a computational methodology to evaluate and compare standard fire exposures such as those outlined in ASTM E119 with real fire exposures and determine the difference in the temperature rise of a rail car floor assembly. The real fire exposures simulated in this work were identified in a review of incidents and consisted of a constantly‐fed diesel fuel spill, a localized trash fire, and a gasoline spill simulated from a collision of the railcar with an automobile. These realistic fire exposures were applied to a variety of exemplar rail cars representative of single‐level and bi‐level passenger cars. These floor assembly models exposed to realistic fires were simulated in Fire Dynamics Simulator (FDS). The thermal exposure at the underside of railcar provided by FDS was coupled with a thermal model in ABAQUS, which provided the evolution of temperature in different components of the floor assembly. The standard scenarios were simulated for 2 hours instead of the typical 30 minutes to identify the appropriate exposure duration in ASTM E119, which can better represent a real fire scenario. The average and maximum temperatures predicted at the unexposed surface for both scenarios were compared with the threshold values given in NFPA 130.

    更新日期:2019-12-11
  • Comparative energy analysis from fire resistance tests on combustible versus noncombustible slabs
    Fire Mater. (IF 1.173) Pub Date : 2019-11-28
    Alastair I. Bartlett, Robert McNamee, Fabienne Robert, Luke A. Bisby

    Standard fire resistance tests have been used in the design of structural building elements for more than a century. Originally developed to provide comparative measures of the level of fire safety of noncombustible products and elements, the recent resurgence in engineered timber construction raises important questions regarding the suitability of standard fire resistance tests for combustible structural elements. Three standard fire resistance floor tests (5.9 m × 3.9 m in plan), one on a concrete slab and two on cross‐laminated timber (CLT) slabs, were undertaken to explore some of the relevant issues. The fuel consumption rate within the furnace was recorded during these tests, and the energy supplied from this was determined. An external fuel supply (from natural gas supplied to the furnace) equating to approximately 3 MW was recorded throughout the concrete test, whereas this was about 1.25 MW throughout the CLT tests. The total heat release rate was calculated using carbon dioxide generation calorimetry; this yielded values of approximately 1.75 MW during the CLT tests (ie, an additional energy contribution of approximately 0.5 MW from the timber). This demonstrates that considerably more energy input (by about 1.25 MW) was needed to heat the system when the test sample was noncombustible. A further series of six large‐scale compartment fire experiments (6 m × 4 m × 2.52 m) was undertaken to further explore comparative performance of combustible versus noncombustible construction when the external fuel load is kept constant and is governed by more realistic compartment fire dynamics. For a fuel‐controlled case, the peak temperatures in the compartment with an unprotected CLT ceiling were approximately 200°C higher than in the compartments with a concrete ceiling, whereas for a ventilation‐controlled case, the compartment with a CLT slab ceiling displayed a burning duration that increased by approximately 15 minutes. Potential implications for standard fire resistance testing of combustible specimens are discussed.

    更新日期:2019-12-11
  • Intumescent polypropylene: Interactions between physical and chemical expansion
    Fire Mater. (IF 1.173) Pub Date : 2019-11-24
    Tsilla Bensabath, Johan Sarazin, Maude Jimenez, Fabienne Samyn, Serge Bourbigot

    To decrease the reaction to fire of a highly flammable plastic, polypropylene (PP), the concept of intumescence was applied. Two intumescent systems were designed on the basis of different mechanisms: physical expansion with expandable graphite (EG) and chemical expansion with modified ammonium polyphosphate (AP). Fire behavior of PP containing EG, AP, or an AP/EG mixture with a total loading of 10 wt% was evaluated by cone calorimetry at 35 kW·m−2. Thermocouples allowed measuring the temperature at the backside or inside samples over time and evaluating the thermal barrier of these intumescent materials. Two grades of AP (difference in composition) and several grades of EG (difference in expansion characteristics) were compared. Mixing AP and EG does not create a synergistic effect in studied conditions. Contrarily, the incorporation of small amount of EG in PP‐AP modifies heat transfer in the coating, creating a strong anisotropy. Graphite worms are trapped vertically into the expanded AP, which increases the transverse heat conductivity (lower efficiency of the thermal barrier) and decreases the fire performance. This phenomenon disappears in thicker specimens. While a higher expansion volume of graphite worms improves fire performances of PP with only small amount of EG (1 wt%), this effect is not noticeable with AP/EG mixtures.

    更新日期:2019-12-11
  • Test methods for characterizing concrete properties at elevated temperature
    Fire Mater. (IF 1.173) Pub Date : 2019-11-17
    Venkatesh K.R. Kodur, Srishti Banerji, Roya Solhmirzaei

    Fire resistance of structural members is dependent on the thermal and mechanical properties of constituent materials and these properties vary as a function of temperature. Currently, there are limited standardized test procedures for evaluating thermal and mechanical properties of construction materials at elevated temperatures. This paper provides a review and assessment of test methods and procedures for evaluating high temperature thermal and mechanical properties of concrete. The drawbacks and variations in currently available test procedures and methods in standards are discussed. Recommendations on the most suitable methods and procedures for measuring thermal and mechanical properties at elevated temperature is presented. In addition, applicability of the proposed high temperature test methods and procedures is illustrated through a case study on conventional concrete specimens. Further, the need for developing standards by organizations such as American Society for Testing and Materials (ASTM), with standardized specifications and test procedures for measuring high temperature properties of construction materials, is laid out.

    更新日期:2019-12-11
  • Study on thermal stability of typical carbon fiber epoxy composites after airworthiness fire protection test
    Fire Mater. (IF 1.173) Pub Date : 2019-11-13
    Xu Zhang, Sen Li, Zhi Wang, Donglin Wang

    The thermal stability of the T700 carbon fiber epoxy composites, which had been tested under different conditions (nonvibration plus nonscrubbing airflow, vibration, scrubbing airflow, and vibration plus scrubbing airflow), were investigated according to the obtained weight loss behavior, integral program decomposition temperature (IPDF), and activation energies (E) by using thermogravietry‐differential thermal analyzer. The results indicate that the weight loss ratio, IPDF, and E of T700 carbon fiber epoxy and its residues in the third and fourth layers are similar under the nonvibration plus nonscrubbing airflow and vibration, and the thermal stability under the vibration condition is slightly stronger. In addition, the weight loss ratio, IPDF, and E of the epoxy and its residues in materials are also similar under scrubbing airflow and vibration plus scrubbing airflow, and the thermal stability under vibration plus scrubbing airflow is better. However, it is significantly less than the thermal stability of materials under nonvibration plus nonscrubbing airflow and vibration. Therefore, it can be found that the vibration exacerbates the flame severity and the scrubbing airflow has a significant cooling effect on the material during the airworthiness fire protection test, which have guiding significance on the airworthiness fire prevention items formulation of carbon fiber composite.

    更新日期:2019-12-11
  • Development and application of a simulation approach for fire and structure interaction of concrete members subject to spalling
    Fire Mater. (IF 1.173) Pub Date : 2019-11-11
    Marc Janssens, Biswajit Dasgupta

    This paper describes the development and illustrates the use of an approach to model the mechanical performance of a concrete bridge and its structural components exposed to fire and subject to spalling. The work is motivated by some recent fire incidents that involved concrete bridges, the poor state of an increasing number of bridges throughout the United States (which makes them more vulnerable to fire damage), and the lack of design codes and standards that adequately protect bridges against fire. An important objective of the work is to develop a method to predict spalling that captures the principal physical and chemical phenomena but is simple enough so that it can be implemented in a 3‐D structural simulation. The first step in the approach involves using a hydrothermal model to determine if and at what temperature spalling occurs for a specified concrete mix (defined by its composition, type of aggregate, water‐cement ratio, porosity, permeability, etc), free moisture content, and heating rate. The second step uses the resulting “critical spalling temperature” in a coupled thermal and mechanical analysis to determine how spalling affects the performance of the concrete member. The approach is illustrated for two standard fire resistance tests conducted on posttensioned concrete slab systems reported in the literature. The paper concludes with a list of recommendations for additional work to improve the predictive capability of the heat and mass transfer and structural models and to address several challenges with the implementation of the spalling criteria in the structural model.

    更新日期:2019-12-11
  • Best practices for modeling structural boundary conditions due to a localized fire
    Fire Mater. (IF 1.173) Pub Date : 2019-11-06
    Alyssa DeSimone, Ann E. Jeffers

    Recent studies suggest the assumption of uniform heating that is used in current structural fire design cannot be assumed conservative, especially if the fire is expected to burn locally. Aside from design equations, which have limited applicability, a common approach to simulating structural members subjected to a localized fire is modeling the fire‐structure interaction using a coupled computational fluid dynamics (CFD)‐finite element (FE) model. In the existing literature, a wide range of methods and parameters are used when determining the boundary conditions at the fire‐structure interface, specifically regarding the representation of net heat flux, heat transfer coefficient, and surface emissivity of steel. The purpose of this study is to investigate various methods for representing the boundary conditions in terms of accuracy and computational efficiency and then identify best practices. In conclusion, our study found that net heat flux predicted by adiabatic surface temperature, a nonconstant heat transfer coefficient, and a surface emissivity of 0.9 for steel was the most reliable thermal boundary condition in a coupled CFD‐FE model of a localized fire. These recommendations are based on the two cases studied here, and caution should be used when applying these results to future studies.

    更新日期:2019-12-11
  • Quantitative fire risk assessment of cotton storage and a criticality analysis of risk control strategies
    Fire Mater. (IF 1.173) Pub Date : 2019-10-10
    Long Ding, Jie Ji, Faisal Khan, Xiaohua Li, Shaoan Wan

    Although fires can easily occur during cotton storage, research on cotton storage fire risk assessment is limited. This work focuses on cotton storage fire risk assessment and investigates the criticality of risk control strategies. Bow‐tie and Bayesian network models are established to investigate the relationships among accident causes, safety barriers, and possible consequences. The results show that the first safety barrier (detection and extinguishment before fire brigade arrival) is more controllable and more effective than the second safety barrier (fire brigade). Based on the collected probability data, the probability and risk of a common accident are higher than those of a large accident and severe accident when safety barriers succeed; when the first safety barrier fails, the probabilities and risks of large and severe accidents increase by more than 2000 times. The criticality of safety measures is investigated by analysing their structural importance, probability importance, and critical importance. The critical events for fire occurrence are an open flame and sparks during storage, and the critical events for detection and extinguishment before fire brigade arrival are watchkeeper monitoring, regular patrolling, and automatic fire alarm systems. For cotton storage safety, this work and its outcomes are used to support the decision‐making of fire risk prevention and control.

    更新日期:2019-12-11
  • A new test methodology for studying the response of walls to real fire environments
    Fire Mater. (IF 1.173) Pub Date : 2019-09-04
    Jennifer Ellingham, Matthew J. DiDomizio, Elizabeth J. Weckman

    A new test methodology was developed to investigate the response of walls, partitions, and in‐wall systems exposed to real fires. The apparatus includes a 3.5 m long, 2.3 m wide, and 2.3 m high fire compartment within a standard sea container. A wall specimen measuring up to 1.8 m wide, 1.8 m tall, and 0.3 m deep is mounted in a steel frame at one end of the fire compartment. Fire exposures to the wall specimen evolve over time depending on the fuel load and ventilation configuration. Gas temperatures and heat flux were characterized for five different fuel and ventilation configurations. Peak exposures ranged from 30 to 75 kW/m2 for about 20 minutes. Five additional tests were conducted using a single fuel and ventilation configuration to assess the repeatability of the test methodology. It was found that a 19.3 minute growth period occurred plateauing at a ceiling temperature of 708°C for 8.4 minutes, on average. Compartment gas temperatures were found to be repeatable, having a sample standard deviation less than 32°C for symmetric data. Repeatability improved when account was taken for the rapid fire growth inflection point. The utility of the approach for studying fire performance of building elements was demonstrated.

    更新日期:2019-12-11
  • The discrepancies in energy balance in furnace testing, a bug or a feature?
    Fire Mater. (IF 1.173) Pub Date : 2019-08-07
    Wojciech Węgrzyński, Piotr Turkowski, Paweł Roszkowski

    The paper aims to explain the differences found in the heat release rate measurements in a large sample of standard fire tests (EN 1363‐1). A total of 379 tests of vertical assemblies was investigated, all performed in furnace SPARK of the ITB Fire Testing Laboratory, in 2015‐2018. The assemblies were subdivided into two groups—wall assemblies and fire‐rated doors. These assemblies were also compared with the results of the test of a wall built with aerated autoclaved concrete blocks that was considered as the benchmark test. It was observed that walls built with highly insulated sandwich panels require less heat to maintain standard thermal exposure conditions (20%‐30% less) than their counterparts built from gypsum plasterboard or aluminium and fire‐rated glass. In case of doors, it was observed that combustible samples required significantly less heat than the benchmark case (40%‐70% less), which indicates that the combustion of the sample inside of the furnace was an additional, significant source of heat release, that may skew the qualitative assessment of their performance in fire. A more in‐depth discussion of the results is provided, with some ideas on the direction of further developments in fire testing.

    更新日期:2019-12-11
  • Fire resistance of cold‐formed steel framed shear walls under various fire scenarios
    Fire Mater. (IF 1.173) Pub Date : 2019-07-16
    Blanca Andres, Matthew S. Hoehler, Matthew F. Bundy

    This paper presents results of large‐scale experiments with varying levels of fire severity on lateral force‐resisting systems commonly used in cold‐formed steel framed buildings. Gypsum‐sheet steel composite panel sheathed walls, oriented strand board sheathed walls, and steel strap‐braced walls are examined. Postflashover fire conditions of two different intensities as well as 1 hour of fire exposure similar to that in a standard furnace qualification test are studied. Additionally, a full‐scale furnished kitchen fire experiment is conducted for comparison. The results highlight differences in the thermal response and subsequent performance of the walls as well as differing sensitives of the walls to pre‐damage, eg, that might occur during an earthquake. The results are part of a larger effort to provide fragilities for these wall systems in response to realistic fires for performance‐based design.

    更新日期:2019-12-11
  • Simulating real compartment fire conditions in a furnace
    Fire Mater. (IF 1.173) Pub Date : 2019-07-14
    Laura E. Hasburgh, Keith J. Bourne, Donald S. Stone, Samuel L. Zelinka

    In the United States, wood has been traditionally used in residential construction. However, the combustibility of wood still limits its use as a building material in prescriptive building codes, and to overcome the limitations, performance‐based codes can be used. In order to properly analyze performance‐based designs, more information on the fire performance of materials is required, including fire performance under different fire exposures. The char rate when timber elements are exposed to the standard time‐temperature curve have been well characterized and can be used to determine the fire‐resistance rating. However, much less is known about the rate of char formation under other fire exposures and time‐temperature curves. In this study, we used time‐temperature data from full‐scale compartment fire tests and applied that data in an intermediate‐scale horizontal furnace. By measuring the furnace temperature, fuel consumption, and heat flux during the various tests, we identified that the furnace could closely replicate the shape of a real time‐temperature fire curve from a ventilation controlled compartment. However, the furnace fell short in terms of meeting the peak temperatures at flashover and heat fluxes expected in a real compartment fire.

    更新日期:2019-12-11
  • Issue Information
    Fire Mater. (IF 1.173) Pub Date : 2019-11-13

    No abstract is available for this article.

    更新日期:2019-12-11
  • Fire suppression performance of a new type of composite superfine dry powder
    Fire Mater. (IF 1.173) Pub Date : 2019-08-13
    Hangchen Li, Li Feng, Dexu Du, Xinxin Guo, Min Hua, Xuhai Pan

    To enhance the performance of existing dry powders and ensure process security, a new type of dry powder based on ammonium dihydrogen phosphate (NH4H2PO4) was prepared. The prepared composite superfine dry powder was denoted as NH4H2PO4/zeolite composite in this paper. The effectiveness of commercial ABC dry powder, superfine dry powder, and the NH4H2PO4/zeolite composite in fire suppression were compared in a small‐sized fire‐extinguishing chamber. Laboratory‐scale tests showed that the NH4H2PO4/zeolite composite had considerably superior fire‐extinguishing efficiency to that of commercial ABC dry powder and superfine dry powder, along with shorter average extinguishing time and less average mass of powders consumed. In addition, the NH4H2PO4/zeolite composite also displayed much improved toxic gas suppression ability. The physical and chemical characteristics of commercial ABC dry powder, superfine dry powder, and the NH4H2PO4/zeolite composite were characterized using a range of techniques of laser particle size analysis, scanning electron microscopy, thermogravimetric analysis, and differential scanning calorimetry. Based on the analysis results, the improved fire suppression performance of the NH4H2PO4/zeolite composite can be ascribed to smaller particle size, larger surface area, and a special chemical decomposition process.

    更新日期:2019-12-11
  • Investigation on flammability of rigid polyurethane foam‐mineral fillers composite
    Fire Mater. (IF 1.173) Pub Date : 2019-07-22
    Anuja Agrawal, Raminder Kaur, Ravinderjit Singh Walia

    This study investigates the incorporation of castor oil–based rigid polyurethane foam with mineral fillers feldspar or kaolinite clay in order to enhance the mechanical, thermal, and flame retardant properties. Influence of mineral fillers on the mechanical strength was characterized by compressive strength and flexural strength measurement. Thermogravimetric analysis (TGA) was performed to diagnose the changes in thermal properties, while cone calorimeter test was performed to ascertain the flame retardancy of the mineral filler–incorporated rigid polyurethane foam composites. Results showed that the foams incorporated with mineral filler demonstrated up to 182% increase in compressive strength and 351% increase in flexural strength. Thermal stability of these composite foams was also found to be enhanced on the incorporation of kaolinite clay filler with an increase in 5% weight loss temperature (T5%) from 192°C to 260°C. Furthermore, peak heat release rate (PHRR), total heat release (THR), smoke production rate (SPR), and total smoke release (TSR) were also found to decreased on the incorporation of mineral filler in the rigid polyurethane foam. So mineral fillers are ascertained as a potential filler to enhance the mechanical, thermal, and flame retardant behaviors of bio‐based rigid polyurethane foam composites.

    更新日期:2019-12-11
  • Heat propagation in thermally conductive polymers of PA6 and hexagonal boron nitride
    Fire Mater. (IF 1.173) Pub Date : 2019-08-01
    Andreas J. Fischer, Yuhua Zhong, Luchong Zhang, Wei Wu, Dietmar Drummer

    Thermally conductive polymers offer new possibilities for the heat dissipation in electric and electronic components, for example, by a three‐dimensional shaping of the heat sinks. To face safety regulations, improved fire performance of those components is required. In contrast to unfilled polymers, those materials exhibit an entirely different thermal behavior. To investigate the flammability, a phosphorus flame retardant was incorporated into thermally conductive composites of polyamide 6 and hexagonal boron nitride. The flame retardant decreased the thermal conductivity only slightly. However, the burning behavior changed significantly, due to a different heat propagation, which was investigated using a thermographic camera. An optimum content of hexagonal boron nitride for a sufficient thermal conductivity and fire performance was found between 20 and 30 vol%. The improvement of the fire performance was due to a faster heat release out of the pyrolysis zone and an earlier decomposition of the flame retardant. For higher contents of hexagonal boron nitride, the heat was spread faster within the part, promoting an earlier ignition and increasing the decomposition rate of the flame retardant.

    更新日期:2019-12-11
  • Impact of flat roof–integrated solar photovoltaic installation mode on building fire safety
    Fire Mater. (IF 1.173) Pub Date : 2019-07-30
    Xiaoyu Ju, Xiaodong Zhou, Junhui Gong, Kun Zhao, Yang Peng, Cong Zhang, Xingyu Ren, Lizhong Yang

    This paper quantifies experimentally the fire‐induced reradiation to roof surface created by flame extension on the back of the flat roof–integrated photovoltaic (PV) array. A gas burner underneath the tilted PV panels was employed as the fire source. The effects of the PV tilt angle, distance from PV panel to roof, and fire heat release rate (HRR) were investigated. The flame extension geometries and flame reradiation heat flux distribution were recorded. The results show that the flame extension length and vertical thickness (ie, the vertical distance from the back surface of the PV panel to the extension flame profile) are reduced with the increase of PV tilt angle and panel‐roof distance but are increased with increases in the fire HRR. A unified nondimensional HRR coupled with all these factors is proposed to quantify the flame extension geometry. Furthermore, a general equation based on the physical relationship between flame radiation and flame geometry is developed to characterize the distribution of reradiation heat flux on the roof surface with the nondimensional local flame thickness. Finally, suggestions regarding PV installations on flat roofs and the selection of roofing materials are given to decrease the possibility of flame propagation underneath the PV arrays.

    更新日期:2019-12-11
  • A numerical study on the effects of naturally ventilated shaft and fire locations in urban tunnels
    Fire Mater. (IF 1.173) Pub Date : 2019-08-27
    Chuangang Fan, Jian Chen, Zhanli Mao, Yang Zhou, Shaohua Mao

    In more and more tunnels, natural ventilation mode with vertical shafts has been gradually employed. However, there are few studies investigating the influences of fire and shaft positions on natural ventilation performance currently. Therefore, this study investigated the effects of the transverse distance from fire source to tunnel sidewall, the longitudinal distance from fire source to shaft, and the transverse distance from shaft to sidewall on natural ventilation effectiveness in a tunnel fire by using Fire Dynamics Simulator. The typical characteristic parameters of smoke, such as mass flow rate, temperature distribution, and velocity vector were analyzed; besides, the phenomenon of plug‐holing was discussed. The results have shown that the mass flow rate of gas exhausted by the shaft decreases slightly with the increase of longitudinal distance from fire source to shaft. When the longitudinal distance from fire source to shaft is constant, changing the transverse distance from shaft to sidewall will have a more obvious effect on the effectiveness of exhausting smoke than changing the transverse distance from fire source to sidewall; in addition, the phenomenon of plug‐holing is more serious when the shaft is close to the sidewall.

    更新日期:2019-12-11
  • An efficient approach to improving fire retardancy and smoke suppression for intumescent flame‐retardant polypropylene composites via incorporating organo‐modified sepiolite
    Fire Mater. (IF 1.173) Pub Date : 2019-09-02
    Sergio de Juan, Junhao Zhang, Pablo Acuña, Shibin Nie, Zhiqi Liu, Wen Zhang, María Luisa Puertas, Antonio Esteban‐Cubillo, Julio Santarén, De‐Yi Wang

    In this work, an efficient approach to improving the fire retardancy and smoke suppression for intumescent flame‐retardant polypropylene (PP) composites is developed via incorporating functionalized sepiolite (organo‐modified sepiolite [ONSep]). The PP composites with different amounts of intumescent flame retardants and ONSep were prepared by melt compounding. The morphology, thermal behavior, fire retardancy, smoke suppression, and mechanical property of flame‐retardant PP composites were studied. The results indicate an appropriate amount of ONSep in the flame‐retardant PP composites can increase thermal degradation temperature and char formation as well as a reduction of the peak heat release rate and total heat release; moreover, the addition of ONSep significantly decreases the CO production, total smoke production, smoke production rate, and smoke temperature. Simultaneously, the impact strength of intumescent flame‐retardant PP composite is also maintained by introducing an appropriate amount of ONSep as compared with that without ONSep.

    更新日期:2019-12-11
  • Structure and thermal property of intumescent char produced by flame‐retardant high‐impact polystyrene/expandable graphite/microencapsulated red phosphorus composite
    Fire Mater. (IF 1.173) Pub Date : 2019-08-26
    Jichun Liu, Hang Li, Haibo Chang, Yunpeng He, Airong Xu, Bingli Pan

    This paper is aimed to illustrate the structure and thermal property of intumescent char produced by flame‐retardant polymers containing expandable graphite (EG). For this purpose, high‐impact polystyrene (HIPS) flame retarded by EG individually or in combination with microencapsulated red phosphorus (MRP) was prepared. The results indicate that the intumescent char from HIPS/EG/MRP composite, which contains a small amount of phosphorus element and more oxygen element, is much more compact and continuous than that from HIPS/EG composite with identical loading of flame retardant due to binding effect of phosphoric acid and its derivatives. The intumescent char produced by HIPS/EG/MRP composite exhibits much enhanced thermal and thermo‐oxidative stability as well as thermal‐insulating effect, which can withstand destruction of heat and oxygen effectively and thus provide a good fire‐proof barrier. The temperature beneath this intumescent char is decreased significantly in case of action by flame. By comparison, the porous and loose intumescent char generated by HIPS/EG composite has poor thermo‐oxidative endurance, and most of it can be consumed in air at high temperature without effective protection for the polymer. This has resulted in remarkable increase in flame retardancy of the HIPS/EG/MRP composite.

    更新日期:2019-12-11
  • Numerical simulation of the fire behaviour of facade equipped with aluminium composite material‐based claddings‐Model validation at large scale
    Fire Mater. (IF 1.173) Pub Date : 2019-09-11
    Virginie Dréan, Bertrand Girardin, Eric Guillaume, Talal Fateh

    The recent fire events in buildings involving combustible cladding systems have raised concerns regarding the risk that these systems can pose. Understanding such facade fires is complex as they involve a combination of various products and system. Facade fire propagation tests at ISO 13785‐1 intermediate scale were performed on different combinations of aluminium composite material (ACM) claddings and insulants. Simulations were addressed to reproduce these tests and were validated in terms of thermal conditions in the system. This allowed additional investigation and understanding of fire propagation on the facade and more accurate determination of the fire behaviour of the overall system. In this paper, the scaling influence on the fire behaviour of ACM clad systems is investigated with simulations performed to reproduce fire tests at the BS8414‐1 larger scale on three different combinations of ACM and insulants. The contributions of the cladding and insulant were numerically investigated. The fire behaviour of each component and of the overall system is validated by comparison with experiments. Simulations and tests show that the ACM cladding is the most important element driving the global fire behaviour of the systems. In particular, ACM‐PE‐based cladding systems, whatever the insulant, show extensive fire propagation while its degradation affects the integrity of the cavity.

    更新日期:2019-12-11
  • Experimental study on fire properties of interior materials used in low‐floor light‐rail trains
    Fire Mater. (IF 1.173) Pub Date : 2019-11-13
    Weiguang An, Kai Liang, Taolin Zhang, Xiangwei Yin, Yuzhou Cong, Yunji Gao, Jianwei Cheng

    In this work, cone calorimeter tests were conducted to investigate fire properties of interior materials (floor covering [FC], aluminum plate covered with paint [APCP], light diffuser [LD], and gel coat [GC]) used in low‐floor light‐rail trains. Ignition time (tig) of each material decreases with the increase of radiative heat flux. The decreasing order of the four samples by ignition time under the same radiative heat flux is LD > APCP > FC > GC. The heat release rate (HRR), peak value of HRR (PHRR), time from ignition to PHRR (tp), fire growth rate index (FIGRA), and fire growth index (FGI) rise with the increasing radiative heat flux. For the FC, LD, and GC, single HRR peak is observed in the HRR history while three peaks are observed for APCP. For PHRR, LD > FC > APCP > GC, while for tp, GC < FC < APCP < LD. Under most conditions, the FIGRA and FGI of the FC is the highest among the four materials. Results of this work are beneficial to evaluate fire hazard of low‐floor light‐rail train and determine the emphasis of fire prevention.

    更新日期:2019-12-11
  • A new approach based on the modified FDS to numerically simulate cardboard box combustion under low pressure
    Fire Mater. (IF 1.173) Pub Date : 2019-11-13
    Rui Zhou, Han Zhao, Junjian Ye, Hui Zhang

    To solve the limitation of the fire test in high‐altitude areas only detecting a limited number of low‐pressure environments, in this paper, appropriate modifications of the FDS source codes were made to generate a new simulator program for low‐pressure applications. Standard fire experiments with different counts (1, 2, 18, and 27) of cardboard boxes were numerically simulated under different pressure levels (101, 90, 75, and 64 kPa). The computation data show consistent trends with the experimental results obtained in the low‐pressure tank at Lang Fang. Furthermore, the simulation results have been examined to show typical quantitative relationships: (a) The peak mass burning rate divided by the fire base dimension is correlated with the product of the pressure squared and the combustible characteristic length cubed. The exponential indices for the 1‐box fire, 18‐box fire, and 27‐box fire are 0.31, 0.29, and 0.29, respectively. (b) The heat release rate and mass burning rate show a good linearity at each fixed environmental pressure. In conclusion, the modified FDS is validated to work well under low‐pressure conditions, which can provide a receivable means to conduct low‐pressure fire simulation and analysis.

    更新日期:2019-12-11
  • Experimental study on flame spread along fuel cylinders in high pressures
    Fire Mater. (IF 1.173) Pub Date : 2019-10-24
    Yanli Zhao, Jian Chen, Youjie Sheng, Xiao Chen, Shouxiang Lu

    Flame spread over solid fuels in high‐pressure situations, such as nuclear containment shells during a pressurized period, has potential to result in catastrophic disaster, thus requiring further knowledge. This paper experimentally reveals the flame spread behaviors over fuel cylinders in high pressures. Polyethylene and polymethyl‐methacrylate cylinders with the diameter of 4.0 mm are used in this study. Ambient gas is air, and total pressures are varied from naturally normal pressure (100 kPa) to elevated pressure (500 kPa). Flame characteristics including flame appearance and flame size and burning rate and flame spread rate are investigated. Results show that in high pressure, the flame appearance is significantly affected. As the pressure increases, the blue flame disappeared, and the color of flame tip changes from luminous yellow to orange as well the orange part extends down towards the base of flame. The dimensionless flame height increases with pressure for pressure below 150 kPa and then decreases with pressure above that level. The burning rates show increasing trend with pressure and are proportional to P0.6 and P0.79 for polymethyl‐methacrylate and polyethylene, respectively. Besides, flame spread rates for polymethyl‐methacrylate and polyethylene both were found to be proportional to P0.5.

    更新日期:2019-12-11
  • Understanding Structure Ignition Vulnerabilities Using Mock-up Sections of Attached Wood Fencing Assemblies.
    Fire Mater. (IF 1.173) Pub Date : 2019-10-04
    Sayaka Suzuki,Samuel L Manzello

    Firebrand production from structure combustion becomes a key factor in the magnitude of how quickly a large outdoor fire may spread. Post-fire disaster investigations suggest that attached building components, such as wood fencing assemblies are known to be prone to ignition in these fires, and may provide pathways to structure ignition. Here, a comparison of ignition results from full-scale fencing assembly experiments conducted using a full-scale wind tunnel facility, to mock-ups of full-scale fencing assemblies using the recently developed experimental capability at the National Research Institute of Fire and Disaster (NRIFD) are discussed. In both experimental facilities, the fencing assemblies were exposed to firebrand showers using custom built continuous-feed firebrand generators with size and mass distributions similar to those generated from structure combustion. Similar ignition behaviors were observed between the full-scale fencing assemblies and the mock-up of full-scale fencing assemblies. Additional experiments are required for other fencing assembly types to further verify these important findings.

    更新日期:2019-11-01
  • Application of Narrow-Spectrum Illumination and Image Processing to Measure Surface Char Formation in Lateral Ignition and Flame Spread Tests.
    Fire Mater. (IF 1.173) Pub Date : 2019-07-06
    Seth Gatien,Tim Young,Matthew S Hoehler,John Gales

    The Lateral Ignition and Flame Spread Test (LIFT) is used to characterize fire ignition and flame spread on solid materials. This test requires the operator to visually monitor the flame spread over a combustible material and manually record the position of the flame during an experiment. Visual inspection limits the quantity of data obtained from a test and introduces uncertainty in the measurement. In this study, we use narrow-spectrum light with a peak wavelength of 450 nm and a digital camera with frequency-matched optical filters to capture images of surface charring, which underlies the flaming combustion, in a LIFT apparatus. The imaging technique reduced unwanted energy emissions from the flame in the visible light spectrum, allowing the test operator to directly view the charring of the material; which is otherwise hidden behind the flames. We describe data processing routines to analyze the sequences of high-resolution images. The method improves temporal and spatial resolution of the surface charring compared to visual observations.

    更新日期:2019-11-01
  • The Performance of Wood and Tile Roofing Assemblies Exposed to Continuous Firebrand Assault.
    Fire Mater. (IF 1.173) Pub Date : 2016-01-01
    Sayaka Suzuki,Daisaku Nii,Samuel L Manzello

    The performance of tile roofing assemblies as well as untreated cedar shake roofing assemblies exposed to continuous firebrand showers were compared. Specifically, experiments were conducted for two types of concrete tile roofing assemblies (flat and profiled), one type of terracotta tile roofing assembly (flat), and an untreated (without any fire retardant) cedar shake roofing assembly. The design of the roofing assemblies were based on construction guidelines in the USA. The duration of the firebrand flux was fixed at 20 minutes, and the wind speed was varied from 6 m/s to 9 m/s. These wind speeds were chosen to be able to compare roofing assembly performance to similar assemblies exposed to a batch-feed firebrand generator which had limited duration of firebrand exposure (6 min). The average firebrand mass flux that arrived at the surface of the roofing assemblies was 0.3 g/m2s Results indicated that for the untreated cedar shake assemblies, ignition occurred easily from the firebrand assault, and this type of roofing assembly generated their own firebrands after ignition. To attempt to quantify the degree of penetration, the number of firebrands that penetrated the tile roofing assemblies, and deposited onto the underlayment/counter-batten system was counted as function of wind speed for each assembly. Firebrand penetration was observed, even for the flat tile assemblies. It is believed that these are the first-ever experiments described in the peer-reviewed literature to expose wood and tile roofing experiments to continuous wind-driven firebrand showers.

    更新日期:2019-11-01
  • Quantifying Wind-Driven Firebrand Production from Roofing Assembly Combustion.
    Fire Mater. (IF 1.173) Pub Date : 2018-01-01
    Samuel L Manzello,Sayaka Suzuki,Tomohiro Naruse

    Large outdoor fires present a risk to the built environment. Examples often in the international media reports are wildfires that spread into communities, referred to as Wildland-Urban Interface (WUI) fires. Other examples are large urban fires including those that have occurred after earthquakes. Firebrands are a key mechanism on how rapidly fires spread in urban fires and WUI fires. An experimental protocol has been developed to ignite full-scale roofing assemblies and quantify the degree of firebrand production during the combustion process. As wind is an important factor in firebrand generation, the experiments were conducted under a range of wind speeds at the Building Research Institute's (BRI) Fire Research Wind Tunnel Facility (FRWTF). A further unique aspect of this work is the experimental results are compared to firebrand size and mass distributions collected from an actual large-scale urban fire in Japan. Results of these experiments demonstrate that when only oriented strand board (OSB) is applied as sheathing, a significant number of firebrands collected from roofing assemblies were less than 1 g and 10 cm2. It was also observed that experiments on individual building component firebrand generation provided useful insights into actual urban fire firebrand generation.

    更新日期:2019-11-01
  • Burning Down the Silos: Integrating new perspectives from the social sciences into human behavior in fire research.
    Fire Mater. (IF 1.173) Pub Date : 2017-09-26
    Erica Kuligowski

    The traditional social science disciplines can provide many benefits to the field of human behavior in fire (HBiF). First, the social sciences delve further into insights only marginally examined by HBiF researchers, in turn, expanding the depth of HBiF research. In this paper, I present examples of studies from the fields of social psychology and sociology that would expand HBiF research into non-engineering or "unobservable" aspects of behavior during a fire event. Second, the social sciences can provide insight into new areas of research; in turn, expanding the scope of HBiF research. In this section, I introduce pre- and post-fire studies and explore potential research questions that fall outside of the response period of a fire, the phase upon which most focus is currently placed. Third, the social sciences elucidate the value of research methods available to study human behavior. Qualitative research methods are specifically highlighted. These three benefits will allow HBiF researchers to collect a wider range of data, further develop and expand current behavioral knowledge, and increase the impact of this research for both social and engineering applications. Finally, I end with a discussion on possible ways to better integrate the social sciences within human behavior in fire.

    更新日期:2019-11-01
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