ABSTRACT Fluorocarbon surfactants are the most widely used stabilizers for enhancing the fire‐extinguishing (FE) efficiency of aqueous film‐forming foam (AFFF). However, perfluorooctane sulfonate (PFOS) generated by long‐chain fluorocarbon surfactants can exist in the food chain for a long time. It can pose a serious threat to the stability of the natural ecosystem. Therefore, the environmentally friendly substitutes for long‐chain fluorocarbon surfactants should be developed as soon as possible. This study explores the effects of expansion ratios, additive types, and additive mass concentrations on the FE time and cooling efficiency of AFFF for flammable liquid fires, showing that the FE process of AFFF consists of three stages: coupling, transition, and stable periods. The minimal FE time, at which the surface temperature of combustibles was significantly reduced, was obtained when the gas–liquid mixing ratio and additive mass concentration were 4:1 and 0.3 wt.%, respectively. The synergistic effects of MCA and FS‐50 quickly reduced fire source temperatures, further enhancing the FE effectiveness of modified AFFF. A series of tests have proven that the AFFF foam mixed with environmentally friendly additives achieved the fire extinguishing requirements specified in national standards.
ABSTRACT The determination of step‐resolved effective heats of combustion is essential for detailed pyrolysis modelling in fire growth and flame spread predictions, especially in multi‐step processes where the heat of combustion can differ between reaction steps. Typically, the effective heat of combustion is determined from the ratio of heat release rate to mass loss rate, measured for example by microscale combustion calorimetry (MCC) and thermogravimetric analysis (TGA). However, reliable determination requires precise agreement between the experimental boundary conditions of both methods, a requirement systematically compromised by inherent deviations in MCC measurements compared to TGA. The literature attributes this limitation to various causes, yet a comprehensive investigation of their origins and combined impact has been absent. A systematic investigation reveals several key causes of these discrepancies. Non‐constant heating rates in MCC render mass loss and heat release events below 170°C invalid for analysis. A temperature gradient within the pyrolysis chamber, revealed through dedicated measurements using an additional thermocouple inserted into the pyrolyser, induces temperature shifts and apparent heating rate deviations. Additionally, baseline correction problems arise at low initial sample masses when using an electrochemical oxygen sensor, which is often implemented in MCC devices. Based on these findings, compensation strategies are developed, evaluated and assessed with respect to their consequences on the resulting effective heat of combustion.
ABSTRACT Fiber‐reinforced polymer composites are widely used in industries such as automotive, aerospace, and defense due to their exceptional properties. In the automotive sector, these composites are particularly required to exhibit high flame‐retardant characteristics. However, the flame‐retardant capabilities of conventional fiber‐reinforced polymer composites are often insufficient for applications demanding enhanced fire safety. This study systematically investigates the individual and combined effects of zinc borate (Z), aluminum hydroxide (A), and magnesium hydroxide (M) microparticles on the flame‐retardant and mechanical properties of glass fiber‐reinforced epoxy composites. In addition to single‐additive systems, multi‐component hybrid formulations incorporating Z, A, and M particles were developed to evaluate the efficacy of single versus multi‐component systems. During composite fabrication, flame‐retardant additives were incorporated into the epoxy matrix at various weight percentages and combinations, followed by lamination using the hand lay‐up method. Subsequently, horizontal burning and mechanical tests (flexural and impact) were conducted on composite specimens according to international standards. The unfilled (neat) composite exhibited the highest flexural and impact strength. As the additive content increased, particle agglomeration due to high surface energy promoted stress concentration sites, leading to a slight reduction in mechanical properties. Conversely, flammability tests revealed that microparticle reinforcement significantly reduced the horizontal burning rate. Specifically, specimens containing 20 wt.% flame‐retardant additives (20A, 20Z, 20M, 10A10Z, and Hybrid2) achieved burning rate reductions of 41.97%, 47.68%, 12.95%, 35.02%, and 23.20%, respectively, compared to the neat composite. Overall, single zinc borate formulations (20Z) demonstrated superior fire suppression efficiency compared to hybrid combinations, offering a practical optimization pathway for fire‐safe automotive composite structures.
ABSTRACT The increasing severity of wildfires poses significant challenges through the release of greenhouse gases and other harmful gases and particles. Although field measurements exist, there is a lack of systematic data collection to understand the influence of moisture content on the particle and gas emissions of boreal fuels, particularly for European boreal forest fuels. This study investigates the influence of moisture content and fuel type on flaming combustion emission characteristics of surface fuels collected from two Swedish forest types, which share key characteristics with fire‐prone forests across the European boreal. The results are based on bench‐scale controlled combustion conditions in a cone calorimeter, where gaseous and particle emissions were measured using Fourier Transform Infrared spectroscopy and an Electrical Low‐Pressure Impactor, respectively. Moisture content of the fuels only insignificantly affected combustion efficiency, with higher moisture content leading to increased emissions of incomplete combustion products (CO, CH 4 and NH 3 ). Thus, although moisture affects the amount of fine fuel consumed in a wildfire, it is not significant for the emissions factors during the flaming combustion. The combustion of mosses was instead significantly less efficient than that of litter for all moisture contents. Average emission factors highlighted clear differences between fuel types, with mosses producing higher CO (87 ± 20 g/kg) and lower CO 2 (1350 ± 220 g/kg) compared to litter (47 ± 12 g/kg and 1620 ± 81 g/kg, respectively). Particle emissions were strongly dependent on fuel type with of 29 ± 12 g/kg for mosses compared to 98 ± 15 g/kg for Pinus sylvestris needles and twigs.
Facade fires are a rare but destructive hazard that can lead to the rapid spread of fire between the floors and fire compartments of a building. Today, there are at least 21 different national standards for facade fire tests in use around the world, which seek to categorize facades based on their flammability. Each of these standards measures some aspect of upward flame spread, alongside other aspects of fire behavior, but the size and geometry of the facades tested, and the type of, and peak heat flux from, the ignition source vary significantly between standards. It is unclear whether these different standards categorize similar facades consistently, such that the results are robust, correct, and safe when applied to buildings. This paper presents a series of 25 experiments: testing five facades (two ETICS and three rainscreen facades) using five test standards (PN-B-02867, ISO 13785-1, DIN 4102-20, NFPA 285 and BS 8414). The average heat release rate was reconstructed and the average vertical flame spread rate was measured to determine whether they varied more with the choice of facade build-up or the choice of standard. We found that different standards could not rank the flammability of the facades more consistently than random chance in terms of flame spread rate, but that the average reconstructed heat release rate provided a consistent rank. Qualitatively, the facades showed similar burning behavior across the different standards, which suggests that it may not be justifiable to use larger, more expensive tests to study facade flammability. However, in some experiments, complex fire dynamics were observed-such as pool fires forming beneath the facade-that could not be captured by simple metrics, and that were sensitive to the details of each standard. This research presents a unique comparison of different facade test standards that can inform fire engineering judgements made from such standards, allowing for the safer use of facades in tall buildings.
The relationship between accidental dwelling fire incidence and fire injury and fatality was examined using a Bayesian model to estimate the probability of a fire injury or fatality resulting from an accidental dwelling fire incidence under different circumstances of fire incidence (type of accidental dwelling fire, dwelling occupancy type, impairment due to suspected alcohol or drugs, and level of deprivation). Accidental dwelling fire incidence and fire injury and fatality data recorded by Greater Manchester Fire and Rescue Service between 2013/14 and 2023/24 were used to develop the Bayesian model. Overall, impairment due to suspected alcohol or drugs consumption appeared to increase the probability of fire injury across the different types of accidental dwelling fire, and the probability of fire injury and fatality resulting from an accidental dwelling fire was highest for candle and smoking-related fires.
To address the problems pertaining to conventional physical inhibitors, such as being prone to failure at high temperatures and having insufficient thermal stability, we selected methylcellulose and polyethylene glycol as thermosensitive materials, dl-malic acid as an antioxidant, and modified ZnO as a nanomaterial. A thermosensitive hydrogel composite inhibitor was synthesized via graft copolymerization and solution polymerization. Scanning electron microscopy revealed that the composite inhibitor formed a porous structure, enhancing its water absorption capacity. Oxidation kinetic analysis showed that the coal samples' activation energy rose by 5.94% in the T 5-T 8 temperature range after inhibition treatment. Diffuse reflectance infrared Fourier transform spectroscopy experiments demonstrated that the inhibitor inhibited the production of functional groups containing oxygen, encouraged the creation of ether bonds, and postponed the consumption of hydroxyl and aliphatic groups. X-ray photoelectron spectroscopy confirmed that the ether bond content on the coal surface increased to 43.97% after inhibition, and newly formed -O- bonds were detected. Finally, this composite inhibitor's synergistic inhibition mechanism was analyzed. The research results reported herein provide a new theoretical basis and useful guidance for the prevention and control of the spontaneous combustion of coal.
Natural hazards driven by extreme weather events are expected to continue to pose a significant risk to citizens, property and the environment. Based on a series of national and international interviews with the Fire and Rescue Service (FRS), this paper presents an analysis of present practices within the FRS and FRS willingness to employ a novel methodology for assessing multiple natural hazards. Based on the interviews, present operational practices and attitudes to digital planning tools have been identified. Both the Swedish and international FRS highlight lack of resources as a limitation regarding planning for natural hazards, and indicate a positive attitude towards interagency collaborations, despite the potential for such collaboration to complicate planning and require improved guidance documents. Further, an overall willingness to adopt new digital tools to plan for natural hazards was identified, provided a good benefit-cost ratio could be ascertained. Finally, the Swedish FRS indicate a greater concern regarding their responsibilities relative to that of other stakeholders in terms of planning for natural hazards, relative to the international FRS. This could support the need for improved clarity in stakeholder responsibilities regarding planning for natural hazards, in particular in Sweden, moving forward.
ISO/TS 19021 specifies a method for time-resolved quantification of selected fire effluent gases generated in the ISO 5659 single-chamber smoke test using Fourier Transform Infrared (FTIR) spectroscopy. To support the revision of ISO/TS 19021 and establish updated precision statements, an interlaboratory trial (round-robin) was organised with 16 laboratories and designed in three steps: (1) assessment of equipment and set-up conformity to ISO/TS 19021 requirements, (2) qualitative and semi-quantitative processing of five shared reference spectra, and (3) replicated testing of four common materials under prescribed irradiance and flaming conditions. Step 1 highlighted deviations that can materially influence performance, including insufficient minimum detection limits for some target gases and heterogeneous calibration descriptions. Step 2 demonstrated strong agreement on major species in spectra dominated by target gases (e.g., CO, CO2, HCl), but also revealed practical limitations: only five laboratories could fully reprocess externally supplied spectra due to software import constraints, and reported numerical values below the ISO/TS 19021 quantification capability (<= 15 mu L/L for most gases; <= 300 mu L/L for CO2) were not robust for quantitative comparison. Step 3 data were analysed in accordance with the ISO 5725 series to estimate repeatability and reproducibility for smoke metrics and gas concentrations at defined times and maxima. Comparison with historical datasets indicates consistency for several measurands while confirming that interlaboratory variability increases markedly at low concentrations and for species detected by a limited subset of laboratories. These findings support targeted clarifications in ISO/TS 19021 regarding quantification limits, spectral interpretation, and harmonised reporting.
Major fire disasters continue to cause substantial loss of life, economic damage, and social disruption worldwide. Although investigations occur in most countries, lessons learned are often fragmented, published in incompatible formats, or not published at all. Therefore, it is recommended that a group be set up of experts to investigate national and international fire incidents in a structured manner and to determine specifically what lessons can be learned for the future.
With climate change and urbanisation increasing wildfire risk in the wildland-urban interface (WUI), enhancing community evacuation preparedness is crucial. This study evaluates different data collection methods for measuring traffic flows during a community wildfire evacuation drill in Roxborough Park, Colorado, in June 2024. A multi-method strategy was applied, including drone footage, human observers (manual and app-assisted), automated traffic counters, questionnaires, and postcards. Methods were assessed based on cost, ease of use, data quality, privacy, and ethical considerations. Results highlight that drone footage effectively captured large-scale traffic flow but required a large number of resources for preparation and post-processing. Human observers provided detailed insights but might be prone to errors in high-traffic areas. Self-reported data (questionnaires, postcards) offered valuable behavioural insights but might be affected by response bias. Automated traffic counters provided continuous data but could not differentiate between drill-specific and background traffic. This study provides practical guidance on selecting behavioural data collection methods for wildfire evacuation research, ultimately contributing to improved emergency planning and community resilience.
Accreditation of fire testing laboratories under ISO/IEC 17025 commonly relies on proficiency testing or interlaboratory comparisons (ILCs). For UN ECE R134 & sect;5.4 fire tests on gaseous hydrogen vehicle fuel containers, no ILCs are currently available. We evaluate the feasibility of using the guide values provided in Annex E of ISO 19881-derived from published reference testing-as external references to demonstrate method performance. Six ECE R134 calibration-tank tests were conducted at Efectis; four compliant tests were retained for analysis. For the six required temperature metrics (localized and engulfing fire phases; burner-side, opposite-side, and worst-case surface temperatures), 60 s means were computed within defined steady-state plateaus. Assuming normality, equality-of-variance (Fisher F-tests) and equality-of-means (Student t-tests) were performed at 95% confidence between Efectis results and ISO 19881 Annex E data. Means were statistically equivalent across all metrics, while the Efectis dataset showed substantially lower variance-particularly for opposite-side measurements. Repeatability (s r), estimated from four in-house repeats, ranged 4%-11% for localized fire and 2%-18% for engulfing fire. Reproducibility (s R), estimated from the pooled ISO-plus-Efectis data, ranged 32%-55% and 15%-47% for localized and engulfing phases, respectively. These findings indicate that Annex E guide values can credibly underpin uncertainty statements and performance claims where formal ILCs are lacking, thereby supporting ISO/IEC 17025 accreditation pathways for ECE R134 & sect;5.4 fire testing. Limitations, uncertainty budgeting, and recommendations for future community intercomparisons are discussed. The discussion also shows that a complete characterization of fire-test severity should include HRR/A in addition to temperature-based acceptance criteria.
Polyamide 66 (PA66) is the most widely produced and used engineering plastic, and it also holds a significant position in the field of chemical fibers, resulting in a large amount of PA66 waste. Recycling PA66 waste not only helps alleviate environmental pollution caused by PA66 waste but also reduces the consumption of fossil resources, which has important practical significance. In this paper, PA66 waste and phytic acid were used as precursors to prepare PA66-based carbon dots (66CDs), a novel zero-dimensional carbon nanomaterial, through a solvent-free one-step pyrolysis method. The optimal excitation and emission wavelength of the prepared 66CDs is 410 nm and 500 nm, and the fluorescence quantum yield is 25.42%. The average particle size of 66CDs is 3.30 nm, and the lattice spacing is 0.21 nm, with surface functional groups such as -OH and -NH2. Subsequently, the as-prepared 66CDs were used for flame retardant finishing of polyester fabrics through double-dip-double-nip method. When the concentration of 66CDs is 10 g/L, the weight gain of the polyester fabric is 1.69% and the limit oxygen index value reaches 29%. The ignition time of finished polyester fabric reaches 219 s with an improvement of 10.60% compared to pure polyester fabric, and the damage length decreased 39.20% compared to pure PET, thus enhancing fire safety of polyester fabric. The study on the flame retardant mechanism indicates that 66CDs play a role in quenching free radicals and promote the formation of a dense char layer in the polyester fabric, thereby achieving the flame retardant effect.
This study quantifies moisture-driven ignition and combustion dynamics in six Mediterranean fuels (Oran, Algeria; Corte, France) using a cone calorimeter (ASTM E1354). A microwave-assisted drying method (800 W, 0.9-0.95 GHz) enabled precise moisture control (< 180 s) while preserving live-fuel integrity. Results revealed an exponential increase in ignition delays with moisture content (R-2 > 0.95) for all species except Eucalyptus globulus, linked to fuel bed compactness (phi, = 13% - 16%) and a characteristic moisture (MCC = 16% - 27%). While low irradiance (17.5 kW / m(2)) rendered the effective heat of combustion (EHC) moisture-independent (preignition drying), high irradiance (50 kW /m(2)) reduced combustion efficiency due to residual water. Notably, Phoenix dactylifera exhibited exceptionally low apparent EHC (4-5 MJ / kg) and prolonged ignition duration (46-58 s), highlighting its potential as a natural fire-resistant material. These findings advance standardized testing for live fuels and inform fire-resistant landscaping in Mediterranean ecosystems.
This study compares the charring behaviour of mass timber under varied heating conditions when protected by either different thin intumescent coating types or fire-rated plasterboard layers. Bench-scale fire experiments were conducted using the Heat-Transfer Rate Inducing System (H-TRIS). Testing included cross-laminated timber (CLT) samples with two opaque coatings (A, B), one transparent coating (C), and one- or two-layer plasterboard assemblies, with bare timber as a benchmark. The dry film thickness (DFT) of the opaque coatings was 2.35 +/- 0.25 mm, while the transparent coating had a DFT of 0.37 +/- 0.03 mm, and each plasterboard layer was 13 mm thick. During testing, samples were exposed to three constant radiant heat flux levels of 25, 50 or 75 kW/m2 for 60 min. Bare timber and samples with transparent coating experienced the most severe charring, while opaque coatings and plasterboard layers provided better insulation. All protected timber samples, even those with the transparent coating, showed a delay in the onset of charring and a level of reduction in the effective charring rate compared to bare timber. This study demonstrated that both thin intumescent coatings and fire-rated plasterboard layers can delay the onset of charring and induce a reduction in the charring rate of mass timber, although increased heating intensities caused deviations in performance. Overall, the coatings were found to be more susceptible to elevated heating conditions than plasterboard, whose insulation capacity was dependent on its moisture content. The opaque coatings provided an equivalent level of fire protection performance to one layer of plasterboard, but the highest level of protection was achieved by the two layers of plasterboard.
Fires in recycling facilities are known for producing noxious fumes, having high heat release rates (HRRs), being difficult to extinguish and causing significant devastation to business operations. This research aims to provide experimental data and numerical models from which performance-based designs can be developed for recycling facilities. Through validating simulation models against experimental data, ignition parameters are verified and can be used as inputs for future larger-scale modelling of flame spread and behaviour. In previous research, cone calorimeter tests were conducted in which the thermal properties (HRR curves, heat of combustion [HOC], time to ignition [TTI]) of recycled plastic pellets were determined. In this research ignition and flame spread are studied, which includes flame spread experiments in a horizontal trough. This data is used to calibrate the density, thermal conductivity, and specific heat capacity by comparing the TTI observed from cone calorimeter testing to that observed in simulated models. The HRR curves and HOC, in addition to the calibrated density, thermal conductivity and specific heat capacity, are used for fire dynamic simulator (FDS) models presented in this paper to simulate and observe the horizontal flame spread rate of shallow samples of plastic pellets made of recycled material. This paper then compares experimental and numerical horizontal flame spread rates and burning behaviour observed. The experimental and simulated horizontal flame spread rates are in the same order of magnitude, 0.2 and 0.35 cm/min respectively, highlighting that the ignition, initial flame spread and model parameters have been suitably captured.
Polylactic acid (PLA) is a biodegradable polymer with promising applications but suffers from high flammability and severe melt dripping. A condensed-phase flame-retardant system was developed by melt blending phosphorylated chitosan (PCS) and halloysite nanotubes (HNTs) into PLA. With a total loading of 9 wt% (8 wt% PCS and 1 wt% HNTs), the PLA/PCS/HNTs blend achieved a limiting oxygen index (LOI) of 29.4% and a UL-94 V-0 rating. Cone calorimetry results showed that the peak heat release rate (pHRR) decreased by 34.9% compared with neat PLA. The enhanced fire performance is mainly attributed to phosphorus-induced char formation from PCS and the reinforcement of the char layer by HNTs, which promotes the formation of a compact protective barrier during combustion. These findings demonstrate that the introduction of HNTs into PLA/PCS systems provides an effective strategy for improving the fire safety of PLA composites.
The flame spread behavior of horizontal combustibles such as pocket coil mattresses in residential houses was investigated under various installation height conditions, and an existing predictive model was refined. In a series of experiments, mattresses were tested with diverse installation heights (ranging from 0 to 515 mm) using the standard ignition source specified by ISO 12949:2011. The experimental results revealed that both the fire growth rate and the maximum heat release rate increased with higher mattress installation height. During combustion, molten material and mattress fragments descended and ignited on the floor. The flames associated with the combustion on the floor affected the combustion of the mattress body, leading to a correlation between higher mattress installation height and increased heat release rates and fire growth rates. Traditionally, flame spread speed is determined by the incident heat flux to the horizontal and upper surfaces of the solid combustible material adjacent to the flame. However, a modified model was proposed that accounts for the influence of both convective and radiant heat fluxes generated by the flames on the floor, impacting the cross-section of the burning mattress body.
Industrial facilities are environments with a high fire risk, where fires can rapidly escalate and cause significant damage if appropriate fire protection systems are not implemented. This study focuses on the critical task of selecting the most suitable fire suppression system for industrial facilities. To achieve this, we identify three main criteria-effectiveness, safety, and operational considerations-along with thirteen subcriteria to guide the selection process. The Spherical Fuzzy Analytic Hierarchic Process (SF-AHP) method is employed to determine the weights of these criteria through expert evaluations, followed by the Spherical Fuzzy Evaluation based on Distance from Average Solution (SF-EDAS) method to rank various fire suppression alternatives. A case study is conducted in a facility dedicated to producing plastic animal cages as a practical application of this methodology. This is a high-risk environment due to the explosive nature of the materials used. The results highlight Reaction Time as the most critical factor, followed by Impact on Operations, Flexibility, and Personnel Protection. In this case study, the clean agent system ranked highest, demonstrating its effectiveness in meeting the facility's specific needs. The proposed approach provides valuable insights for industrial plant managers aiming to enhance fire safety and protect personnel and assets in high-risk environments.
Fractional vegetation coverage (FVC) is an important indicator for measuring ecosystem function and environmental quality. This study, using MODIS data from 2001 to 2022, investigates the spatiotemporal dynamics, driving factors, and predictive performance of FVC in Anhui Province of China. The results show that over the past 20 years, FVC in Anhui has significantly increased, with more than 80% of the region showing an upward trend, and 47.72% of the area experiencing highly significant increases, while less than 7% showed a decline. The annual mean FVC increased from 0.64 to 0.74, exhibiting a clear spatial gradient of "high in the south, low in the north." Feature correlation analysis revealed that temperature and evapotranspiration are the main environmental drivers of FVC. Temperature can promote the growth of vegetation and increase its coverage, while evapotranspiration is closely related to regional water stress. In the established predictive modeling, the XGBoost algorithm outperformed random forest and ridge regression, demonstrating the best predictive performance on the validation set (R 2 = 0.83). While the individual analytical methods employed are well-established, the primary innovation of this study lies in constructing an integrated framework that bridges traditional long-term spatiotemporal statistics with advanced ensemble machine learning. This methodological integration successfully transitions regional vegetation analysis from retrospective observation to high-precision dynamic forecasting. Ultimately, by accurately forecasting vegetation trends under varying thermal and moisture conditions, this research fills a critical gap in Anhui Province, providing robust, data-driven support for climate change adaptation strategies, targeted afforestation planning, and sustainable land-use policymaking.
