Experimental and modeling efforts are made to develop a new approach to estimate sprinkler protection requirements for warehouse storage. The approach incorporates different models to predict water penetration effectiveness and critical delivered flux, as well as fire plume/ceiling jet correlations to predict the required sprinkler discharge density and number of sprinkler activations for an adequate protection in various storage configurations. The objective is to develop a reliable and repeatable means to estimate protection requirements for varying practical scenarios (target) based on limited large-scale fire tests (baseline). The newly proposed approach is validated using large-scale fire tests with solid-piled plastic pallets. The validation shows good agreement between modeled results and experimental data with an error less than 20%, when the suppression ratio was similar between target and baseline tests. Overall, this work should be viewed as a step towards a more cost-effective framework for designing fire protection systems.

Exposing cross-laminated timber (CLT) structures in buildings is increasingly popular in modern buildings. However, large timber surfaces, window facades, and different geometries can change the fire dynamics in a compartment. The effect of those parameters, therefore, needs to be studied. Two large-scale CLT compartment fire experiments (95 m2) have consequently been performed. The experiments were designed to represent a modern office building with an open-plan space and large window openings. In this experiment, #FRIC-01, the ceiling was exposed. The wood crib fire developed slowly and travelled approximately 1.5 m before the ceiling ignited at 32.5 min. Thereafter the fire spread rapidly across the ceiling and wood crib before it shortly after retracted. Three such cycles of rapid spread followed by a retraction occurred within 13 min, whereby the wood crib fire grew larger for each cycle. After the flames extended through the compartment for the fourth time, the fire remained fully developed. After a short period of intense burning, the CLT self-extinguished while the wood crib fire was still burning. The compartment withstood full burnout, and no reignition occurred despite some delamination and using an adhesive that lacks a demonstrated resistance against glue-line integrity failure.

A time-temperature curve, representing the fire characteristics of structures, can be obtained by real fire experiments. However, these experiments are inherently susceptible to data loss, which can compromise the accuracy of results. To address this challenge, this study proposed the framework utilizing a long-short-term memory (LSTM) with Bayesian optimization to reconstruct temperature histories by learning the spatiotemporal correlation of the data. The proposed framework is first validated using simulated datasets from computational fluid dynamics analyses. The field applicability of the model is further demonstrated through real fire test results, affirming its reliability in practical scenarios. The study also introduces a novel data processing technique to mitigate overfitting issues in LSTM applications with limited data, enhancing the robustness and reliability of temperature history reconstruction. Overall, the results highlight the potential of deep learning in accurately and practically reconstructing temperature histories in fire experiments.

This study aims to characterize the effects of multilayered coatings on the performance of distributed fiber optic sensors (DFOS) when the coatings experience softening and melting at high temperatures. Two strain sensors (B-DFOS and W-DFOS) and one temperature sensor (Y-DFOS) were calibrated. They were either embedded along the centerline of a mortar bar or bonded on the surface of the specimen. The Y-DFOS was found to be no longer strain-free at high temperature since the softened sheath, aramid yarns, buffer, and polymer coatings became viscous and adhered to their surrounding mortar above softening temperatures 263–320 °C. Both the B-DFOS and W-DFOS captured uneven strain distributions along the mortar specimen due to non-uniform temperature distribution, mortar heterogeneity, and temperature-dependent strain transfer efficiency. The W-DFOS showed higher measured strains than the calculated thermal-induced strains at 100 °C - 300 °C due to the high thermal expansion coefficient of the additional buffer layer. The B-DFOS gave smaller measured strains than the thermal-induced strains at 300 °C - 500 °C. The displacement calculated by integrating the measured strains along the length of each mortar specimen was related to the applied temperature by parabolic regression equations.

In order to study flow stratification behavior in lateral smoke exhaust mode, experiments were carried out in reduced-scale model and numerical simulations model. The characteristics of smoke layer interface, smoke layer thickness, vertical temperature and normalized shear velocity in tunnel with different heat release rates were analyzed. The flow pattern was visualized by a semiconductor laser. The stratification pattern was found to fall into three regimes. Buoyancy, inertia force and suction force, as three factors affecting the flow stratification of smoke, are related by a new dimensionless number. At region I (Frs4.8), the stratification becomes unstable, the mixing between smoke and cold air was intense, and there is no obvious stratification interface.

Fire accidents caused by liquid fuel leaks occur at times. In this paper, the combustion behavior of thin layers formed by the free spread of methanol at six continuous leakage rates was studied. The results show that methanol combustion with continuous leakage can be divided into four stages according to the change of burning area. The quasi-steady burning rate of thin-layer fuel is lower than that of pool fire at the same scale, due to the rapid heat exchange between the fuel layer and the substrate. As measured and calculated, the average fuel layer thickness gradually decreases in the spread burning stage, rises in the shrink burning stage, and finally reaches stability. The average fuel layer thickness of the quasi-steady burning stage of each case is used to calculate the heat loss by substrate reflection. Based on the law of energy conservation, a heat equilibrium model of the quasi-steady burning stage of a thin layer combined with fuel flow heat transfer was established. This model explains the uneven substrate temperature found by experimental measurements. The calculation results show that the effect of flow heat transfer is more significant within 20% of the burning area near the leak leakage port.

The failure mode of a structural component subjected to fire loading is sensitive to its mechanical boundary conditions. It follows that controlling boundary conditions is crucial to obtain a realistic loading scenario with a fire experiment. Hybrid fire testing has been developed for this purpose. Specifically, a structural component under test is loaded using actuators and exposed to fire loading. A coordination algorithm updates actuator setpoints on the fly so that the tested structural component experiences the sought mechanical boundary conditions, e.g., associated with a virtual assembly that is simulated numerically.To enable interoperability of simulation tools and control systems utilized in hybrid testing, a number of middlewares have been proposed, some of which have been adapted to hybrid fire testing. Middlewares facilitate the implementation of hybrid fire testing within the same laboratory. However, the portability of hybrid models from one laboratory to another is critical when different middleware and simulation tools are adopted. A consequence of that is that round-robin verification cannot be easily deployed for hybrid fire testing.In response to this limitation, this paper proposes to craft hybrid fire testing experiments using the Co-Simulation paradigm supported by the Functional Mock-up Interface standard. The methodology is demonstrated experimentally.

The present paper is dedicated to the modelling of real scale multi-compartment and multi-source fire scenarios and its validation against real scale experiments. The scenarios consist in a one or two fire sources located in a three mechanically ventilated compartments, communicating through vertical openings. The scenarios show complex behaviour and bring new knowledge to the field of compartment fires. It is interesting to assess the ability of the models to predict such complex scenarios. The three scenarios are modelled using the zone model MAGIC, which shows good agreement with the experiments. A second part of the work consists in the use of the Peatross and Beyler correlation to predict the fire behaviour. This correlation, which is intended to account for confinement in a predictive way, is implemented in the zone model MAGIC to achieve this goal. This work is original since this correlation has not been yet applied to such complex scenarios. The important aspects of the correlation, like the reference mass loss rate and the oxygen concentration, were discussed in detail. The correlation is found to give good predictions.

Post-fire mechanical assessment of steel structures is challenging due to the changes in mechanical properties from the heating and cooling phases of a fire. While the effects of cooling rate and temperature of exposure have been researched in depth, the effects of heating duration are not comprehensive. This paper investigates the effects of heating duration on post-fire A572 Gr. 50 steel mechanical properties over a temperature range of 500–800 °C for durations of 0.5 and 2.0 h. Specimens are subjected to tensile testing in accordance with ASTM A370, Vickers microhardness testing, and optical microscopy. The findings suggest that heating duration has an influence on the post-fire mechanical properties of steel at elevated temperatures (700, 800 °C). At these temperature exposures, retention of yield stress, retention of ultimate stress, and microhardness all decrease. Members subjected to 700 °C for 0.5 h have more retention in yield stress and microhardness compared to those exposed for 2.0 h, while the 800 °C conditions show little difference in mechanical properties between exposure times. The results of this study show that the duration of fire exposure is an important factor when estimating the mechanical properties of fire-exposed steels, in addition to the temperature and cooling rate.

Limited research has explored differences between child and adolescent's who set fires. The current study sought to investigate age differences in firesetting-related risk factors, motivations and behaviours in a large sample of children and adolescents (n = 1790) referred to the New Zealand Fire Service intervention programme (FAIP). Children were significantly less likely than adolescents to have engaged in pre-intervention offending, used an accelerant during their firesetting, and be motivated by boredom. Conversely, children were significantly more likely than adolescents to have set fires in their own home and to have experienced hyperactivity problems, neglect, household deprivation and negative feelings when lighting fires. This study identifies that family dysfunction, victimization and psychosocial and behavioural problems emerge early in the lives of children and adolescent's who set fires. Our findings suggest that there are likely several developmental and behavioural pathways related to firesetting, which necessitate the development of robust assessment practices and systematic interventions in response.

When a severe fire occurs in the central part of a large hollow core slab floor, the thermal expansion of the affected floor members will be highly restrained by the stiffness of the surrounding structure. The present paper presents the development of a numerical model to evaluate the structural performance of precast concrete hollow core slabs exposed to fire, taking into account the interaction with the surrounding structure and how it affects the fire resistance and failure mode. The performance of the model is validated against fire tests reported in the literature. Subsequently, the model is employed to evaluate the influence of various degrees of restraint on the fire resistance of three hollow core slab sections, with depths ranging from 200 mm to 500 mm. The results indicate that restrained thermal expansion can significantly enhance the fire resistance of concrete hollow core slabs with low span-to-depth ratios. Conversely, in hollow core slabs with a high span-to-depth ratio, the restraint provided by the surroundings can considerably impair the fire performance. Additionally, it is shown that the failure mode of hollow core slabs can change from ductile bending failure to a brittle shear failure mode in the presence of axially restraining boundary conditions.

Electrical fires are a significant cause of dwelling fires, but the existing information on electrical fires is often vague and imprecise, making it challenging to develop a comprehensive risk assessment method. To address this problem, this paper proposes a risk assessment method based on Fuzzy Petri nets (FPNs), a modeling tool that is suitable for complex systems under uncertainty. This approach allows for modeling various relationships between risk factors and their respective importance, supplying a flexible and comprehensive way to perform risk assessment. The proposed method involves responding to a yes/no questionnaire based on code recommendations, which allows for the prediction of the failure mode response. Based on the simulation results, it can be evaluated the overall risk, determined the relevance of each electrical issue in a residential distribution system, or assessed the impact of electrical installation improvements and alterations on safety. Despite the complexity of failure modes modeling, this approach offered a practical and straightforward means of identifying potential electrical fire risks.

In composite steel decking concrete slabs, fire design has to be made according to EN 1994-1-2. However, its procedures are questionable by many references. This is due to the divergence between full-scale experimental research methodologies and numerical studies with different analysis criteria, producing different conclusions. This research sought to numerically study the fire performance of composite steel decking concrete slabs according to two criteria (C): C1, assuming the same temperature field in the cross section, corresponding to a pre-defined ISO 834 fire rating of 30, 45, 60, 90, 120, 150 and 180 min, and an applied load increasing over time; and C2, assuming the increasing temperature field (slab is heated following ISO 834 fire curve) and a constant load over time applied to the slab. C1 allows to define the ultimate load for each pre-defined time of ISO 834 fire curve, while C2 the thermo-physical-mechanical effects. For the parametric calibration of the numerical models, 12 full-scale slabs were tested. 6 slabs under four-point bending test for mechanical parameter definition. Other 6 slabs for fire testing according to ISO 834 fire curve, for thermal and thermomechanical parameter definition. It was clearly noticed that current requirements of the standard are based on criterion C1, as it presented results that are close to the simple flexural theory. However, C1 does not allow defining increase in stresses produced by heating, which is noted only in C2. In C2 it was possible to identify the concrete cracks and detachment of the decking. In some cases, the concrete stresses produced in C2 were opposite to those shown in C1. It is understood that C2 shows more realistic results, but generates greater complexity and processing time for defining the ultimate load for each ISO 834 fire curve time.

Wildfires currently represent an imminent danger to communities around the world due to their increasing severity and frequency. It is critical to expand current knowledge on wildfire behaviour to improve risk management practices, firefighting operation and engineering design in the Wildland Urban Interface (WUI). This paper reports 2D high resolution measurements of Byram's fireline intensity generated during a 150 × 200 m2 gorse shrub burn generated from visual and infrared video footage of the prescribed fire, and Light-Detection-and-Ranging (LiDAR) data of the vegetation canopy, both acquired using Unmanned Aerial Vehicles (UAV) technology. The results show that the fireline intensity was highly variable across the plot, reaching localized peak values over 40,000 kW/m and an averaged intensity of 14,300 kW/m approximately. An empirical correlation for estimating the average flame height was derived from the fireline intensity maps and from experimental measurements carried out during the prescribed burn. The correlation was used to produce a 2D detailed map of the average flame height of the prescribed fire, achieving a 11% of error compared to in-fire measurements. The findings from this research suggests that non-linear variabilities of fireline intensity should be carefully considered to adequately describe wildifire behavior of shrubland fires.

Well-planned evacuation is an effective and often necessary tool to protect life in communities threatened by wildfire. In previous incidents, community evacuations have been called too late resulting in entrapment, such as in Mati, Greece in 2018. The most reliable method to determine the safe time to call an evacuation is through trigger boundaries, perimeters on the landscape surrounding a community where the approaching wildfire is an amount of time away from the community equal to the evacuation time. This paper presents a new tool, k-PERIL, that calculates stochastic trigger boundaries, based on the variability of wildfire behaviour around a community due to the influence of historic wind, weather and vegetation variations on the wildfire. k-PERIL is applied to the rural community of Roxborough Park, Colorado, USA, producing probabilistic trigger boundaries and showing the model's ability to find and quantify areas of elevated uncertainty of evacuation. The concept of uncertainty rosettes is introduced, which show the areas where incoming wildfires cause larger variation to the boundary location because of higher sensitivity to changes in fuel, wind or evacuation. The k-PERIL tool can be used to inform effective evacuation preparation and enhance long term planning, improving community safety and wildfire resilience.

The ‘travelling fire’ models have been used to describe the localised and travelling burning of uniform fuel bed in large open-plan building space. However, fuel is typically distributed non-uniformly in the built environment, leading to complex fire spread behaviours. This paper investigates the effect of non-uniform fuel load distribution on fire development in a sufficiently-ventilated space. A series of fire tests up to 3.5 MW with different wood crib layouts are categorised into two types, i.e., non-uniform and continuous, and non-uniform and discontinuous. The leading and trailing edges of the flame, height of flame, and fire spread rates are estimated using visual evidence. The non-uniform fuel load distribution fundamentally changes the spreading behaviour of fire. On a continuous wood crib, the fire spread rate and fire size are generally proportional to the fuel load density when the arrangement of the wood crib is similar. However, when wood cribs are discontinuous, the fire dynamics depend more on the localised burning size and gaps between fuels. Furthermore, very distinct fire behaviours were observed for fuel loads with different porosity. This work reveals the possible under-estimation of fire hazards of assuming evenly distributed fuel load and suggests considering design fire scenarios of non-uniform fuel load distribution in the performance-based fire safety design.

A simple two-zone subgrid temperature distribution is developed to model turbulence-radiation interaction in the Fire Dynamics Simulator. The new approach enforces consistency between the subgrid flame distribution and the heat release rate from the eddy dissipation model. To investigate the performance of the new model, we simulate the University of Maryland turbulent line burner and compare global radiative fraction as a function of coflow oxygen dilution. The results suggest that the model can improve grid resolution dependence in prediction of radiative emissions. Sensitivity of the model predictions to the assumed fuel carbon to CO fraction (a parameter of the two-step fast chemistry scheme) was found to be significant, which is not surprising since this parameter essentially controls the in-flame soot concentration and generally has a first-order effect on resolved emission. Four different model variations were tested, corresponding to varying degrees of complexity in modeling the subgrid correlations for the absorption coefficient. Differences in results between model implementations were on par with the variation in results obtained with different path lengths applied to the gray gas model for the absorption coefficient.

A number of real-scale field tests were carried out on a mobile turbine rescue and firefighting system (MTRFS), equipped with a 10 kN SO3 aircraft turbine, using the energy of exhaust gases to disperse water currents with an intensity of 6 m3min-1. The performed tests have proven the feasibility of applying a fog stream with the surface coverage intensity Iz ≥ 2 mm min−1 at a distance of 90 m and an area of 657 m2. The highest efficiency of the system was obtained at a distance between 25 and 70 m, with the maximum surface coverage intensity being Iz(max) = 14.43 mm min−1. These results indicate a significant potential for the use of water mist generated by jet engines in rescue operations conducted from a distance, e.g. elimination of hazardous substance clouds or operations intended to protect objects exposed to thermal radiation. On the other hand, significantly lower maximum surface coverage intensity generated by the water mist stream than that in the case of using the water monitor generating a droplet stream (Iz(max) = 113.48 mm min−1) indicates a much lower potential for extinguishing group A fires, which require significant wetting of the material. Tests carried out on the traditional vehicle system of supplying solid and dispersed water streams through a Turbo Jet monitor have demonstrated the necessary presence of these systems to achieve optimum operability of vehicles equipped with turbine extinguishing systems.

A machine learning-based heart health monitoring model, named H2M, was developed. Twenty-four-hour electrocardiogram (ECG) data from 112 career firefighters were used to train the proposed model. The model used carefully designed multi-layer convolution neural networks with maximum pooling, dropout, and global maximum pooling to effectively learn the indicative ECG characteristics. H2M was benchmarked against three existing state-of-the-art machine learning models. Results showed the proposed model was robust and had an overall accuracy of approximately 94.3%. A parametric study was conducted to demonstrate the effectiveness of key model components. An additional data study was also carried out, and it was shown that using non-firefighters’ ECG data to train the H2M model led to a substantial error of ∼40%. The contribution of this work is to provide firefighters on-demand, real-time status of heart health status to enhance their situational awareness and safety. This can help reduce firefighters’ injuries and deaths caused by sudden cardiac events.

Calcium hydroxide (Ca(OH)2) and magnesium hydroxide (Mg(OH)2) are promising fire suppressors because of their characteristics of nontoxic, cost-effective, and high fire suppression ability. In this work, a comprehensive study of fire inhibition of slaked lime and dolime slurries, containing different ratios of Ca(OH)2 and Mg(OH)2, was implemented for the first time. A synchronised imaging system was developed for the visualisation of the droplet evolution temporally. The chemical components were analysed by X-ray diffraction and thermogravimetric analysis. A single droplet test and a variable volume test were performed to measure the charcoal surface temperature under different conditions. The results demonstrated that the Ca(OH)2 slurry better inhibits combustion in comparison to water, which could significantly decrease the risk of fuel re-ignition. The main mechanism was found as the effective inhibition of the exchange of the oxygen and fuel by the thermally stable residues. Additionally, either adding the mixture of Mg(OH)2 or increasing the solid content of the Ca(OH)2 could further improve their effectiveness. Three stages of the fire suppression were identified in this work and a conceptual model was built accordingly to demonstrate the fire inhibition mechanisms. The results from this work could provide important guidance for the research into alternative methods of fire extinguishment.