Compartment Fire Research Articles

Инженерный метод расчёта площадей пожарных отсеков в общественных зданиях

Purpose. The analysis of domestic and foreign regulatory documents showed that the regulatory requirements for the areas of fire compartments cannot be considered as scientifically based. It is necessary to develop a new approach to substantiate quantitatively the sizes of fire compartments. Methods. When making calculations, the area of fire compartments must meet certain criteria. An economic approach to calculating the size of fire compartments with the criterion of incurred costs is proposed. The areas of fire compartments must meet the conditions for fulfilling the optimization criterion, which takes into account the costs of creating fire protection for the building and the risk of material losses in case of a fire. Findings. The authors have presented analytical expressions of criteria to make a decision on the economic feasibility of using an automatic fire extinguishing system or fire walls, based on the criterion of incurred costs for one-story public buildings. The resulting formulas determine the critical areas of fire compartments; if these values are exceeded, it is advisable to use automatic fire extinguishing systems or divide the building into two fire compartments. Three options to determine the size of fire compartments for a one-story building have been considered. Research application field. The results can be applied in the context of alternative design of fire compartment areas when developing fire protection for specific facilities in compliance with the principle of economic feasibility. The formulas are simple and suitable for engineering calculations. Conclusions. It is proposed for facilities where fires can cause significant material losses, including social components of fire risks, to use the economic approach to determining the area of fire compartments based on optimizing the criterion of incurred costs. When comparing options for fire protection of a facility, the option that provides the minimum value of the criterion should be chosen. For three protection options: without fire walls and automatic fire extinguishing systems, with the use of automatic fire extinguishing systems or using fire walls, analytical expressions for the areas of fire compartments have been found.

Possibility of Fire Spreading Owing to Radiant Heat from Fire Shutters in Logistics Facilities

The mock-up experiments were conducted to confirm the possibility of fire spreading, such as ignition of commodities (e.g., cardboard boxes), owing to the radiant heat, in the event of a fire in the fire shutter, which is the main fire compartment element that forms the fire compartment of logistics facilities. From the experiment, it was found that commodities located at a distance of 1, 2, and 3 m from the fire shutter can be ignited by the radiant heat of the fire shutter in the event of a fire, which can affect the spread of the fire. Therefore, to prevent the spread of the fire to neighboring fire compartments in the event of a fire in logistics facilities, it is necessary to restrict the placement of commodities within a certain separation distance from the fire shutter or install a fire shutter with radiant heat limiting performance. It is important to improve standards related to fire shutters in logistics facilities.

Study on Fire Load and Duration of Fire in Logistics Facilities

Logistics facilities differ significantly from general buildings in terms of diffusion flame prevention technology, necessitating the application of fire diffusion prevention technology. The total fire load in a fire compartmentation was calculated according to the method presented in The NFPA (The National Fire Protection Association) Fire Protection Handbook, based on the results of a survey on the area, height, and rack dimensions of 29 logistics warehouses in Korea to improve the fire compartmentation standard. In addition, simulations were conducted using CFAST (Consolidated Fire and Smoke Transport) for the cross-validation of these methodologies. Through fire simulations, the temperature of the upper part of each fire compartment was derived, and the equivalent fire duration was calculated by converting it to an area based on the standard time-heating temperature curve of KSF 2257-1. The NFPA methodology and values calculated through fire simulations showed similar results. In addition, we analyzed the tendency of the equivalent fire duration according to the height of the fire compartmentation and confirmed that the higher the floor height, the higher the equivalent fire duration. The results of this study can be used as basic data for improving the fire prevention standards by calculating the equivalent fire duration according to the fire load of a logistics facility and for confirming the tendency of the equivalent fire duration according to the height of the fire compartment.

A Proposal and Research on Regulations of Exception and Mitigation for Fire Compartments in Building

Buildings are equipped with fire compartments to prevent the spread of fire. However, the fire compartment regulations in South Korea are simplistic and standardized, and the exception and mitigation also have ambiguous criteria, requiring adaptations to accommodate changes in architectures. Therefore, the purpose of this study is to examine the contents related to exception and mitigation for fire compartments in South Korea and propose to make up for the limitations. To identify limitations, this study investigates how fire compartments are implemented in South Korea and analyze international cases to compare fire compartment regulations. The comparative analysis reveals that domestic exception and mitigation have ambiguous spatial criteria, and international cases solve this issue by specifying regulations based on specific uses. Consequently, this study proposes the need to formulate and detail regulations of exception and mitigation considering both building use type and space characteristics, because of fire hazard levels changed by building use type.

Mathematical Modelling of Smoke-Filling Dynamics in Compartment Fires: A Two-Zone Approach

Mathematical Modelling of Smoke-Filling Dynamics in Compartment Fires: A Two-Zone Approach

The Effect of the Fuel Location and Ventilation Factor on the Fire Dynamics of Informal Settlement Dwellings

AbstractThree full-scale experimental compartment fires are compared to investigate the effect of the fuel location and the ventilation factor on under ventilated thermally thin bounded ISO-9705 compartments. Wood cribs were used as the fuel load and the crib placement was varied between two locations (back and middle) to study the effect of the fuel location. Furthermore, the ventilation conditions were changed from a door and window (i.e., ventilation factor of 2.58 m5/2) to only a door (i.e., ventilation factor of 2.26 m5/2) for the scenario where the cribs were placed at the back of the compartment. The novelty of this work lies in its examination of the time to flashover, gas layer temperature, heat release rate, and external radiative heat fluxes, specifically considering the impact of fuel location and ventilation factor. It was observed that placing the fuel package in the middle of the compartment led to a longer growth phase, hotter gas layer temperature, a higher Heat Release Rate (HRR) needed for flashover ($$\dot{q}_{fo}$$ q ˙ fo ), and higher external radiative heat fluxes through openings. It was also found that, decreasing the ventilation factor decreased the heat losses and therefore the $$\dot{q}_{fo}$$ q ˙ fo . Decreased ventilation also affected the height of the neutral plane, as one would expect, and the shape of the external plume, but did not have significant effect on the temperature within the compartment, the walls of the compartment, and the external radiative heat flux.

Integrating glass breakage models into CFD simulation to investigate realistic compartment fire behaviour

Glass failure affects the ventilation conditions in compartments, which particularly varies the fire development history in large compartments as the initial ventilation may become insufficient due to the existence of window glass. This paper proposes a ‘criterion-controlled’ model to simulate the interaction between glass failure and fire behaviour in CFD fire models. The proposed modelling approach has shown good performance in simulating the Shield Test, where the predicted cracking points and timeline of glass failure are almost identical to the test records. By implementing the glass failure model in the large compartment fire models adapted from the Kirby Test and the Malveira Test models, the influence of glass failure on the large compartment fires has been revealed. In the adapted Kirby Test model with glass panes, the case with window glass exhibits a much faster fire growth compared to the case with initially opened windows of no glass. When considering the window glass failure in Malveira Test model, the slow ‘travelling fire’ behaviour found in the full-scale test is changed to a fast spread fire and the window glass panels fail to provide the desired ventilation, which suggests the inadequacy of assuming complete openings at windows and it is necessary to consider the effect of window glass to large open-plan compartment fires in real modern buildings.

Experimental and numerical study on fire-induced collapse of double-span steel portal frames

This paper introduces experimental and numerical investigations on the fire-induced collapse behavior of double-span steel portal frames. A natural fire test was conducted on a 16 m × 6 m portal frame, and a localized collapse occurred. Thermal and displacement responses of the test frame were measured and analyzed. It was found that the steel members inside the fire compartment experienced similar temperature-time curves, which reached 1000 °C in 15 min. The heated column experienced upward expansion and downward contraction, while the side columns were pushed outside and pulled inside during the fire test. The measuring accuracy and practicability of the thermocouple, microwave radar, inclinometer, and linear variable differential transformer (LDVT) in real fire measurements were compared and evaluated. Numerical models were established in FDS and ABAQUS to simulate the thermal and structural response of the test frame and validated against experimental results, respectively. Parametric analysis was conducted on the validated numerical models with various combinations of heating conditions, heating rates, load ratios, and base stiffness. The collapse temperature of the burning frame was 1.2 and 1.1 times the temperature when the displacements of the heated side column reached their peak values along the span and height directions, respectively.

Understanding the effect of char oxidation on wood temperature profiles for varying heating and oxygen conditions

The use of mass timber framing as a sustainable material, particularly in high-rise buildings, requires detailed structural fire performance calculations. Thermal models describing only the solid phase are cost-effective alternatives to provide information to structural behavior models. Their accuracy depends on an adequate description of drying, pyrolysis, charring and eventually flaming phenomena. While in recent years there have been considerable contributions to the development of such models, there are still open questions. This work proposes a thermal model which incorporates char oxidation, describing both the kinetic- and diffusion-controlled regimes. The model was used to replicate two sets of experimental results which used standard fire calorimeters to study the ignition of thick wood specimens within a range of incident heat fluxes and oxygen concentrations, respectively. The model yields adequate temperature predictions in the early heating stages, but fails to replicate the behavior at later stages, when the effect of the surface combustion is noticeable. In terms of mass loss rates, a poorer performance is observed. To change from one oxidation regime to another, a Damköhler number is proposed, based on char oxidation reaction rates. It is found that for compartment fire conditions, char oxidation will mostly occur develop under diffusion-controlled conditions.

Oscillatory burning regime in a gas-fueled compartment fire

The paper presents a series of 48 enclosure fire experiments carried out in a 1.40 m cubic compartment with a door-like opening of 0.80 m width and a variable height from 0.25 to 1.40 m. The fire source was a propane-fueled square burner of 0.17 m side length positioned in the center of the compartment and delivering a steady mass flux that has been varied in the tests from 0.5 to 5.0 g/s. In addition to the well-known well-ventilated and under-ventilated regimes, an oscillatory combustion regime has been uncovered for an opening height of 0.25 or 0.35 m. This regime is characterized by an alternation between the well-ventilated regime (combustion exclusively inside the compartment) and the under-ventilated regime (combustion inside and outside the enclosure). It is believed that the time for the onset of the oscillations is linked to the smoke filling time. Furthermore, depending on the specific conditions, the oscillations are either steady (until shut-off of the fuel supply) or transitory (leading to a sustained under-ventilated regime). The frequencies ranged from about 9 to 19 mHz. The oscillatory regime has previously been mainly reported for liquid fuels and thus associated to radiative heat feedback effects. The new data for a gaseous fuel calls upon a better understanding and a further analysis of the underlying physics.

Flashover in Aircraft Cargo Compartment at Different Pressures: Experimental and Modeling Study

The increasing incidence of aircraft cargo compartment fires in recent years has caused heavy losses and drawn attention to understanding the combustion process, especially under low pressure. The present paper aims at exploring the conditions of flashover at different pressures. Experiments were conducted in Guanghan (96 kPa) and Kangding (60 kPa), which are located at different altitudes. Five different sizes of pool fires were tested and smoke temperature and heat flux were measured for flashover criteria analysis. Corresponding simulations were performed using a commercial software FDS to examine the pressure effect on the flashover phenomenon and to validate the simulation results. The critical conditions for the onset of flashover in a 1/4 MPS compartment were found to be (1) an average upper layer temperature of about 450 °C at 96 kPa or about 550 °C at 60 kPa, and (2) radiant heat flux at floor level of about 10 to 15 kW/m2 at 96 kPa or 20 to 25 kW/m2 at 60 kPa. By using the average upper layer temperature as a criterion in modeling, a relatively accurate prediction of flashover onset time could be obtained at 96 kPa and a delay of about 25 s was found at 60 kPa.

Fully-developed compartment fire dynamics in large-scale mass timber compartments

A series of large-scale experiments has been conducted on under-ventilated mass timber room compartments with kerosene pool fires. To characterise the role of exposed timber walls on the fully-developed phase of the fire, the exposed surface area of mass timber was varied between experiments. Experiments with all timber surfaces protected were compared against compartments with the ceiling and one or two walls exposed. The results show that increasing the surface area of exposed timber alters the flow fields both inside the compartment and at the doorway. The momentum-driven flow fields control the spatial distribution of temperatures, surface heat fluxes, and the neutral plane. Temperatures, heat fluxes and velocities within the compartment are shown to be spatially heterogeneous in both horizontal and vertical planes, highlighting the complexity of the flow fields. This represents a significant divergence from the conventional assumptions for under-ventilated compartments of minimal velocities and homogeneous thermal conditions governed by the opening factor. The results demonstrate that the momentum-driven flow fields created by the burning walls control the compartment fire dynamics. Therefore, typical simplifications of the momentum equation in zone models are not valid for mass timber compartments, and these solutions should only be used in a conservative manner.

Fire behavior in compartment containing timber constructions focusing on pressure increase owing to pyrolysis gas

A series of full-scale compartment fire experiments was carried out to understand the fire behavior in compartment containing wooden constructions. The opening size and the surface area of combustible materials were adjusted to investigate the differences between ventilation-controlled and fuel-controlled fires. The results show that there was a time lag between when heat release rate (HRR) began to decrease and the time when the temperature in the compartment began to decrease in the case of with a wooden wall and ventilation-controlled fire; the HRR at the time when the temperature began to decrease was about the peak HRR of the case without a wooden wall. Although the HRR in case with a wooden wall was much higher than those without it, the temperature in the compartment with a wooden wall was slightly lower under ventilation-controlled conditions. These suggest that the amount of inflow air was limited by the increase in pressure in compartment due to pyrolysis gas.Furthermore, a model of compartment fires that takes this increase in pressure into account was developed, and it is able to more accurately reproduce the temperature characteristics than models that do not.

Comparative Study of Numerical Simulation and Experiment on Temperature Distribution and Central Vent Flow Velocity in Ceiling-vented Compartment Fire

In this study, we conducted numerical simulations to analyze fire phenomena in a compartment with a ceiling vent and compared these numerical simulation results with previous experimental data. Based on the previous experimental conditions, under the heat release rate of 1.5 kW, the vent areas of 1% and 10% of the floor area and the fire sources both at the center and side of the floor were tested. Overall trends of temperature distribution and central vent flow velocity in the present numerical simulations were consistent with those in the previous experiments. The temperature within the compartment was observed to be higher when the vent area was smaller. For compartment with a smaller vent area, the temperature distribution showed minor variations with the fire source location. However, with a larger vent area, temperatures were notably higher when the fire source was at the side than at the center. The present numerical simulations slightly overestimated the temperatures from the previous experimental results, resulting in a bias factor of 1.07 and a model's relative standard deviation of 0.07 for temperature. Regarding the flow velocity at the center of ceiling vent, the fluctuations over time were more pronounced when the fire source was centrally located. When the fire source was at the center, the average central vent outflow velocity was higher for compartment with a larger vent area. When the fire source was positioned to the side, the vent area appeared to have minimal impact on the average central vent outflow velocity. It was also observed that the average central vent outflow velocity was higher when the fire source was centrally placed when compared to a side location. The present numerical simulations underestimated the previous experimental results for the average central vent outflow velocity, and the bias factor and the model’s relative standard deviation for the average central vent outflow velocity were 0.63 and 0.39, respectively.

Assessment of the Performance of FireFOAM in Simulating a Real-Scale Fire Scenario Using High Resolution Data

An assessment of the performance of FireFOAM in simulating a large-scale compartment fire scenario is presented in this study, using the Edinburgh Tall Building Fire Test I (2017) as the basis for evaluation. Different mesh geometries and sizes are tested, and both theory-based and experiment-based validation approaches are employed. The theory-based validation revealed that the implemented finite volumes method is generally conservative, but unaccounted deviations of up to 20% for the heat release rate were observed due to errors in numerically modelling subgrid phenomena, particularly with tetrahedral meshes. In the experiment-based validation, the simulated data showed good agreement with experimental measurements for flow patterns inside the compartment, neutral plane height, and temperatures outside the ceiling jet. However, there were relatively large errors in incident radiation in the hot gas zone, thermal boundary layer transient temperatures, and compartment inflow/outflow velocities. Systematic errors were attributed to deficient heat transfer boundary conditions and under-estimated air entrainment. The study also identified ways to improve run-time efficiency by implementing parallel processing or reducing solid angles in FVDOM, although using large meshes (30 cm and 40 cm cell size) resulted in faster run-times at the cost of accuracy.

Experimental and theoretical investigation of an adjacent wall on the occurrence of flashover

In urban or informal settlement fires, the influence of an adjacent inert wall/dwelling on the fire development of the burning dwelling is still unknown. Therefore, 41 compartment fire experiments were conducted with a ¼ scale ISO 9705 room, with a calcium silicate board acting as the inert wall, was placed in front of the burning compartment's opening with distances between 50 and 1250 mm. Parameters such as the mass loss rate of fuel, temperatures of gas and walls, heat flux imposed on the floor, and time to flashover were analyzed. From the experiments, it was found that the flashover occurrence times differed significantly with or without the adjacent dwelling, and the time to flashover increased gradually with increasing distance from 50 to 300 mm between the burning compartment and adjacent wall, but decreased with distance from 300 to 600 mm. The heat flux to the floor was calculated and correlated well with measured values, confirming that the observed experimental phenomenon was primarily caused by the interaction between the combustion efficiency of fuel and the different heat losses from hot gas flowing out from the opening depending on the adjacent wall location. Moreover, a modified MQH method and a theoretical model were proposed to predict the gas temperature and time to flashover, respectively.

Fire spread in a large compartment with exposed cross-laminated timber and open ventilation conditions: #FRIC-02 - Exposed wall and ceiling

Cross-laminated timber (CLT) is becoming increasingly popular due to its many advantages. However, it has been shown that exposed CLT can have a significant effect on fire dynamics and spread rates. Further studies are therefore needed to better understand the impact of CLT to fire safety. Two large-scale CLT compartment fire experiments (95 m2) representing a modern office building have been performed, #FRIC-01 and #FRIC-02. This paper presents the second experiment, #FRIC-02, with exposed CLT on the back wall and the ceiling. The fire developed fast and spread across the room in less than 3.5 min from ignition of the wood crib on the floor and in 1.5 min after the ignition of the ceiling. Large external flames were observed, despite the compartment being well-ventilated. The 5-layer CLT, which comprised a 40 mm thick exposed outer layer and was face-bonded using a common European polyurethane adhesive, exhibited glue-line integrity failure and led to a second flashover after a significant period of decay. Subsequent layers of 20 mm also delaminated before the fire was manually extinguished after 3 h. Compared to #FRIC-01, the fire spread rate was faster, and temperatures, charring rates, heat release rates and external flames were higher.

Fuel loads and their composition, and compartment characteristics in educational, office and library buildings

AbstractThis paper presents the fire load data in educational, office and library buildings, obtained through an extensive inventory survey. This data collection effort is prompted by a growing need to simulate compartment fires, wherein estimating realistic fire scenarios is essential to assess the level of fire severity in a structure, and consequently the strength of the various structural members at elevated temperatures. The attributes of compartment fires primarily depend upon the fuel load and its composition, compartment dimensions, ventilation characteristics, and construction materials. Despite an acute need, fire load data across the world is scarce and outdated, and does not reflect the change in the type of materials in‐use today. The survey data presented in this paper is collected from 108 rooms in 10 educational buildings, 51 rooms in three office buildings, and 13 rooms in a library building. This paper also presents the composition of fire loads and the levels of ventilation in these buildings. The studies show that fire loads can vary significantly depending on the room‐use; thereby basing fire load values solely on the overall category of a building may result in either conservative or unsafe design. This study also finds that certain room types (e.g., computer labs) have significant plastic‐based fuels, indicating that typical modelling recommendations based on cellulosic fuels for heat release rate, combustion heat, etc. may not always be appropriate. The paper finally examines the statistical distribution that best describes the measured values of the fire load densities.

Experimental study on fire characteristics of sidewall fires in a long-narrow compartment with multiple lateral openings

This experimental study delves into the fire characteristics within a long and narrow compartment equipped with multiple lateral openings. The investigation encompasses aspects such as radiant heat flow, temperature distribution, and smoke layer height. The presence of lateral openings introduces asymmetry in suction, resulting in augmented radiative heat flow on the rear side of the fire source compared to the front and left sides. Smoke stratification remains stable, with minimal temperature influence from the fire source power at one opening and negligible impact at the other. Employing a customized two-dimensional method for thermal estimation, our experimental data display lower results than previous predictions due to structural disparities. The utilization of the N-percentage rule unveils two discernible regions in smoke layer height behavior: stable and decreasing, a pattern consistent across varying heat release rates. These insights offer valuable predictive tools for discerning fire characteristics in elongated, restricted compartments with multiple lateral openings. Consequently, this study enhances comprehension and informs safety measures within such configurations, contributing to the broader field of fire safety engineering.

Detailed description of the flow fields induced by a fire in a mechanically-ventilated compartment obtained using PIV

This study analyses the performance of non-intrusive PIV (Particle Image Velocimetry) for the study of flows induced during a fire scenario in a mechanically-ventilated enclosure. PIV can be used to obtain detailed measurements for velocity fields in the enclosure and thus offer new experimental data for the understanding of the physical phenomena involved as well as to validate CFD simulation tools. The study is carried out on a reduced scale on an ethanol pool fire positioned in a ventilated enclosure. Several areas of interest are studied such as interaction between the fire plume and the ceiling, the flow under the ceiling and parietal flows. These zones can be analysed to obtain a picture of the global mean flow and associated velocity fields rarely reported in the literature. The influence of the fire heat release rate on the velocity fields is studied and highlights the design parameters.