Full-scale Fire Tests Research Articles

Experiment study of fire characteristics in full-scale bedrooms under different vents and sprinkler conditions

The risk of fire in residential buildings is relatively high, with a significant number of incidents and loss of life reported. This study aimed to examine fire scenarios in bedroom by conducting real scale experiments with different set-up of vents and using realistic fuel loads. Five full-scale compartment fire tests were conducted, and a sprinkler system was installed in one of the rooms. The experimental setup, fuel arrangement, and instrumentation are described, and the fire characteristics was analyzed based on visual observations and temperature data processing. The performance of the fire detectors and sprinklers in the tests are discussed. The influence of opening size on the peak temperature, heat release rate, and the constant coefficient of Kawagoe law are estimated and analyzed. Furthermore, a non-dimensional neutral plane height was found to have strong relationship with the constant coefficient of Kawagoe law.

Fire test study of full-scale air-supported membrane structure in large space

The fire safety issue has been a potential hazard in the rapid development of air-supported membrane structures. Therefore, to obtain the fire response of the air-supported membrane structure, the full-scale fire test of the air-supported membrane structure was designed and carried out, and the fire damage mode was discussed. The fire damage characteristics of the air-supported membrane structure are concluded by analyzing the firepower, air temperature, internal air pressure, and structural deformation. The test results show that the fire’s synergistic effect of high temperature and high air pressure makes welded seams damaged earlier than the membrane. Moreover, damaged parts and opening doors of the structure lead to air leakage. When the air leakage exceeds the air intake, the internal air pressure will drop rapidly, causing the structure to collapse. The collapse at the emergency exit is faster than the structural roof, significantly reducing the available time for safe evacuation.

Scaling Study of Smoke Spread from Building Integrated Photovoltaic (BIPV) Double Skin Façade Fire for Achieving Sustainable Buildings and Cities

Due to the shift to sustainable design of buildings and cities, the building integrated photovoltaic (BIPV) is getting more attention. However, this technology may bring new challenges to safety in buildings and cities, i.e., fire safety issues regarding BIPV fire induced smoke propagation in double skin façades (DSF). To study this phenomenon, it is essential to conduct experiments, in which full-scale fire experiments are often inefficient regarding economics and safety. To cope with these issues, this study proposes a new scaling method, which applies the helium sub-scale tests to replace full-scale fire smoke tests for buildings with DSF during BIPV fires. To verify this scaling method, three groups of cases are defined and simulated by fire dynamic simulator (FDS), i.e., full-scale with fire (FSF), small-scale with fire (SSF) and small-scale with helium (SSH). Then, a small-scale experimental model is constructed to validate the FDS model. At last, the simulation results are compared among SSH, SSF and FSF cases, which show acceptable agreement. Therefore, the new scaling method of smoke spread from BIPV DSF fires is justified, which can be applied to the study of BIPV DFS fires induced smoke control in urban scale.

Full-scale tests of load-bearing LSF walls made of built-up CFS channel sections under fire conditions

Built-up cold-formed steel (CFS) studs, such as back-to-back channels (BC) and nested channels (NC) are used in light gauge steel framed (LSF) wall systems instead of the conventional channel studs for improving their load-bearing capacity. However, the knowledge and understanding of their behaviour under fire conditions is limited. In this study, the behaviour of load-bearing LSF walls made of BC and NC studs under fire conditions was investigated using four full-scale standard fire tests. The obtained fire test results were evaluated in terms of both thermal and structural behavioural characteristics and fire resistance level (FRL), and were used in the comparison with those for conventional LSF walls made of single channel studs. The test results showed that (1) without cavity insulation, the thermal and structural behavioural characteristics of the LSF walls made of BC and NC studs are very similar to those of LSF walls made of channel studs, and their FRLs can be taken as the same for the same load ratio (2) LSF walls made of BC and NC studs with two layers of 16 mm thick gypsum plasterboards on each side and without cavity insulation have an FRL of 120 min for a load ratio of 0.4, and (3) the use of cavity insulation reduces the FRL of LSF walls made of NC studs. This paper presents the details of this research study and its outcomes.

Experimental and numerical evaluation of RC ribbed slabs in fire conditions

RC ribbed slabs are an important structural member in building construction. Nevertheless, experimental and numerical research on them in the event of fire is lacking, and their fire behavior is still not well characterized. This paper evaluated the thermal field of RC ribbed slabs subjected to a fire situation. Two full-scale fire tests with slabs prototypes (3.6 × 4.6 m) were carried out according to the ISO 834 [1] time–temperature curve for 120 min. In the fire tests, the thermal field of the slab cross section was monitored, as well as thermal insulation, mid-span deflections, concrete cracking and longitudinal elongation. According to the experimental results, slabs with different flange thicknesses, width and height of the ribs, and position of the reinforcements were numerically evaluated through ABAQUS software. New equations were proposed to define the temperature in the steel rebars and concrete, as this is necessary information to use the Simplified Method of EN 1992-1.2 [2] for the fire design of these slabs.

An approach for early-warning collapse of planar steel trapezoid trusses exposed to fire

This paper presents an approach for early warning of the fire-induced collapse of planar steel trapezoid trusses based on real-time measurement of displacements and displacement velocities of key nodes. Firstly, a three-dimensional finite element model is validated by a full-scale fire test of a steel roof truss structure. Secondly, numerical simulations on the collapse process of planar steel trapezoid trusses under fire are conducted. Four collapse modes are summarized based on systematic parametric analyses. By exploring the variation laws of displacements and displacement velocities of key nodes, the early-warning characteristic points are determined, and a three-level early-warning method is proposed for identifying the collapse mode and collapse state. To improve the generality of the proposed method, dimensionless early-warning time ratios are introduced, and their values, with reliability significance, are determined by the Monte Carlo method. Then the accuracy of this proposed method is validated against an existing fire test. Finally, a numerical case study is presented to illustrate the effectiveness of the method for actual planar steel trapezoid trusses in real fire conditions. The accuracy of the proposed approach is validated with a satisfactory agreement between the precise remaining safety time and that early warned.

Fire spread among multiple vehicles in tunnels using longitudinal ventilation

The characteristics of fire spread among multiple vehicles in tunnels using longitudinal ventilation were investigated by analyzing the experimental data from a series of fire tests in a 1:15 scale tunnel. Further, a simple theoretical model for gas temperature in a tunnel with multiple fire sources was proposed and used in analysis of the experimental data. The results showed that, for objects (wood piles) placed at a same separating distance downstream of the fire, the fire spread occurred faster and faster along the tunnel. Validation of the simplified temperature model for multiple fire sources was made against both model and full-scale tunnel fire tests. The model was further used to predict the critical conditions for fire spread to the second and third objects. Comparisons with the test data showed that average excess temperature of 465 K (or an equivalent incident heat flux of 18.7 kW/m2) could be used as the criterion for fire spread, and this was verified further by other model-scale tests and full-scale tests. The results showed that the critical fire spread distance monotonously increases with the heat release rate, and decreases with the tunnel perimeter. For multiple fire sources with equivalent heat release rates, as the separation distance between the first two fire sources increases, the critical fire spread distance from the second fire source to the third fire source decreases, but the total fire spread distance from the first fire source to the third one increases. If the total heat release rate at the site of a downstream fire source is greater than that at the former fire source, the critical fire spread distance becomes longer.

Fire-Resistance Testing Procedures for Construction Elements—A Review

Fire accidents are a significant risk to human life and civil infrastructure. As a countermeasure, the regulatory bodies of different countries have established standards for evaluating the performance of construction elements during fire exposure. ISO 834 is the globally accepted fire-resistance testing standard. Other standards include ASTM E119, BS 476, IS 3809, JIS A 1304, AS 1503, EN 1363, and GB/T 9978, which are utilized by the US, Britain, India, Japan, Australia, Europe, and China, respectively. This article presents a summary and comparison of the fire-resistance testing standards. In reality, standard tests for isolated structural members may not efficiently portray realistic fire scenarios due to the fire location, its intensity, etc. Thus, researchers have utilized a variety of specialized setups and full-scale non-standard fire tests to fulfill their research objectives. The article includes a summary of selected full-scale, ad hoc, and specialized setups that were reported in the literature. The article highlights the need for timely updates of fire standards to accommodate the testing of newly developed construction materials, structural systems, and possible regional fire scenarios. The article also identifies the research areas that require significant focus in experimental structural fire-resistant testing.

Experimental and numerical studies of fire behavior of cold-formed steel center-sheathed walls subjected to gravity loading

It is a challenge for the conventional cold-formed steel (CFS) sheathed wall system to be adopted in multi-story buildings due to its limited lateral load capacity and stiffness. Therefore, an innovative cold-formed steel center-sheathed shear wall (CFSCSSW) system with better lateral load capacity and stiffness has been proposed and shown its potential application in multi-story buildings. However, the fire performance of CFSCSSW has become one of the major issues which have yet to be investigated and thus become the focus of the present paper, underpinned by tests and numerical simulations. In this study, a full-scale test at room temperature was firstly conducted on a CFSCSSW to obtain its vertical load capacity, while another four full-scale fire tests were then carried out with applied gravity loads to investigate the influence of the interior stud, load ratio, and aspect ratio on fire behavior of the walls. Following the tests, 11 finite element models were subsequently developed to investigate the influence of various critical parameters, such as the axial load ratio, aspect ratio, and end stud thickness, on the fire resistance of CFSCSSW. The fire test results showed that the heat loss of the wall surface could be more than 40% during the temperature transition from the fire exposed side to the cold side. It is found that the presence of interior stud, increasing the aspect ratio beyond 3.0 as well as the load ratio to be greater than 0.3 can result in a transition of the failure mode of the wall from global buckling to local buckling. The critical temperature declines approximately 12% if the load ratio increases by 0.1. The fire resistance of the wall was slightly improved with the increase of the aspect ratio. The end stud thickness of 2 mm is recommended preferentially based on the parametric results. In addition, it was found that the presence of the interior stud has little influence on the fire resistance of the walls.

Full-scale fire testing of battery electric vehicles

The market share of electric vehicles, powered by lithium-ion batteries (LIB), has been expanding worldwide with the global momentum towards green technology and improving the driving range on one full-charge. Studies are, however, still required on the fire safety of the latest but unmatured technology due to a distinctive phenomenon called thermal runaway. In this study, a series of full-scale fire experiments were conducted, focusing on the understanding of thermal behaviours of battery electric vehicle (BEV) fires. To provide up-to-date information on BEV fires, the latest BEV model with a high electric-energy capacity (64 kWh) was selected. For comparative analysis purposes, a LIB pack and a BEV body were tested individually after being physically disassembled. An internal combustion engine vehicle and a hydrogen fuel cell electric vehicle were also tested. During testing, the combustion of the BEV fires continued for approximately 70 min, resulting in critical measures of burning being determined; peak heat release rate (pHRR), total heat released (THR), fire growth parameter, and the average effective heat of combustion were measured to be 6.51–7.25 MW, 8.45–9.03 GJ, 0.0085–0.020, and 29.8–30.5 MJ/kg, respectively. It was also observed that the pHRR and THR were governed by the combustion characteristics of typical combustible materials in the passenger cabin, rather than by that of particular contents in the LIB pack with thermal runaway. Instead, a jet fire intensively discharging from the LIB pack led to a rapid flame spreading to adjacent combustible components of the BEV, thereby accelerating the fire growth. The findings could contribute to the activities of the first responders to BEV fire accidents, fire safety engineers, and structural member designers. This study also makes public the measured thermal quantities for further studies on the fire safety of existing or designing car-parking related structures.

Impact of Mass Timber Compartment Fires on Façade Fire Exposure

This study investigates whether timber surfaces that are initially exposed to fire or partially protected timber components can lead to a more critical fire exposure on the façade. Five full-scale fire tests were carried out. Three tests with a square compartment (4.5 × 4.5 m2) and two with a double-width compartment (4.5 × 9 m2). The tests were conducted with a high fire load density (1085 MJ/m2). While the first test was carried out in a non-combustible compartment, the exposed timber surfaces were subsequently increased in the other tests. The measured compartment gas temperature, heat release rate, temperature on the façade, flame heights along the façade, heat flux and velocities along the façade are presented in this publication. The influence of exposed or only initially protected timber surfaces on the fire impact on the façade is investigated with the help of these results. Finally, these findings are presented and compared with the results of other internationally conducted fire tests from literature. Additional structural fire load leads to an increase in temperatures on the façade. However, there is no significant difference in flame height between the tests. Another result was that an exposed mass timber ceiling leads to higher heat fluxes on the façade than an exposed mass timber wall.Graphical

Real-time detection and forecast of flashovers by the visual room fire features using deep convolutional neural networks

Flashover occurs in building fires whereby all the combustible materials in an enclosure begin to ignite rapidly. This detrimental phenomenon occurs because of the intense heat radiating from the hot smoke layer accumulated near the ceiling, which is one of the major causes of firefighter fatalities. Thus, forecasting flashover in real-time is of great importance to firefighters’ safety. Previous empirical and theoretical analysis of the flashover phenomenon provides criteria for predicting flashover on-set and fire size, yet they are based on the thermal sensor data in the room. It is not straightforward to transfer the flashover criteria and understanding from the previous studies in application to actual fire grounds since thermal sensor data are not readily available. As a novel non-invasive prediction technique of flashover onset, this investigation explores the potential of recognizing vision indicators of flashover, such as flame extrusion or rollover. Adopting artificial intelligence (AI) technologies for pattern recognition and feature extraction, we proposed to build an optimized convolutional neural network named “FlashoverNet”, a modern AI algorithm, to detect and forecast flashover occurrence in enclosure fire incidents. FlashoverNet was trained and validated by data from several full-size actual room fire experiments. FlashoverNet imitates the approach of flashover onset prediction by firefighters by monitoring fire growth and looking for early visible indicators in a room fire. Our investigations demonstrate that FlashoverNet can successfully detect and forecast flashover onset in real-time with more than 94% accuracy in full-scale actual room fire tests.

Building Artificial-Intelligence Digital Fire (AID-Fire) system: A real-scale demonstration

The identification of building fire evolution in real-time is of great significance for firefighting, evacuation, and rescue. This work proposed a novel framework of Artificial-Intelligence Digital Fire (AID-Fire) that can identify complex building fire information in real-time. The smart system consists of four main parts, Internet of Things sensor network (data collection and transfer), cloud server (data storage and management), AI Engine (data processing), and User Interface (fire information display). A large numerical database, containing 533 fire scenarios with varying fire size, positions, and number of fire sources, is established to train a Convolutional Long-Short Term Memory (Conv-LSTM) neural network. The proposed fire digital twin is demonstrated and validated in a full-scale fire test room (26 m 2 ). Results show that the AI engine successfully identify the fire information by learning the spatial-temporal features of the temperature data with a relative error of less than 15% and a delay time of less than 1 s. Moreover, detailed fire development and spread can be accurately displayed in the digital-twin interface. This proposed AID-Fire system can provide valuable support for smart firefighting practices, thus paving the way for a fire-resilient smart city. • A smart building digital twin was developed to identify fire scene in real-time. • Wireless IoT sensors and deep learning model drive the digital twin of building fire. • AI model identifies fire information in digital twin with an error <15% and time lag <1 s. • The digital fire system demonstrates a prototype of future smart firefighting system.

A multi-neural network fusion algorithm for fire warning in tunnels

Fire early warning plays a key role in fire-fighting actions for alleviating the potential casualties of the trapped personnel and firefighters. This paper targets to achieve a fast detecting whether fire occurs or not in urban utility tunnels during fire initial stage by using the data-driven artificial intelligence algorithm. To improve the correct forecast rate, an auto-enhanced multi-trend back propagation neural network algorithm is developed based on the two betterments. One is that many neural networks are constructed to a strong multi-neural network for achieving enhanced-fusion prediction. Another is that one special trend extraction part is coupled in the algorithm to enhance the perception of no obvious temperature variation trend during fire initial stage. Finally, two kinds of full-scale tunnel fire tests were conducted to support the ability and effectiveness of the algorithm. The algorithm can successfully detect whether fire occurs or not with a 96.8% correct forecast rate by learning the temperature data during fire initial stage, even if the maximal range of temperature change is less than 3°C. In addition, to achieve such a high correct forecast rate, only one sensor is necessary for fire early warning in 60 m long tunnel by using the algorithm.

Bench-scale fuel fire test for materials of rechargeable energy storage system housings

The fire behaviour of electric vehicles (EVs) differs from that of vehicles with combustion engines. Especially the rechargeable energy storage system (REESS) requires special fire protection measures. The fire behaviour of materials for REESS housings plays an important role in the fire resistance of such systems. Full-scale fire resistance tests like gasoline pool fire tests on complete REESS according to the UNECE-R100-8E standard are mandatory for EVs. However, these tests are not applicable for materials used for REESS housings in the material and process development state, due to the high material demand and production costs of the REESS. Standard tests like the limiting oxygen index test, UL94-V test or cone calorimeter test are insufficient to analyse the fire behaviour of thermoplastic and thermoset materials in a gasoline pool fire. This paper describes a bench-scale fuel fire test including several test criteria to evaluate materials for REESS housings on a laboratory scale. This bench-scale fire test is demonstrated on two case studies: fibre-reinforced thermoset plates and thermoplastic sandwich structures.

Fire tests with lithium-ion battery electric vehicles in road tunnels

Alternative propulsion technologies, including battery-electric vehicles, are becoming increasingly prevalent. Whilst such vehicles remain a small overall proportion of the vehicle fleet, the combined impact of government policy and technological advances in alternative fuels is expected to accelerate the increase in their numbers in coming years.As a result of these changes, the nature of tunnel safety risk (including the risk of fire) is expected to change over time. The risk implications associated with such vehicles thus requires more detailed consideration. This entails evaluation of incident consequences with particular attention being paid to the impact of fire characteristics and toxic emissions on tunnel users and to the need for specific emergency intervention strategies.In the past, concerns were voiced with respect to the fire safety of the new energy storage device (battery) and the possibility of more difficult firefighting conditions. This resulted in a series of investigations concerning the safety aspects of batteries and battery electric vehicles. However, most of the tests performed merely dealt with battery cells or battery packs. To date, publicly available tests involving actual vehicles remain relatively rare. In 2018, the Austrian Government commissioned a research project concerning the effect of incidents with battery electric vehicles on tunnel safety. This project encompassed fire tests of passenger cars, simulations for heavy duty vehicles, and the impact of incidents with such vehicles on the safety of tunnel users and the tunnel structure.In a series of fire tests, the heat-release and production of (toxic) substances has been evaluated. The burning behaviour of vehicles with different energy storage technologies (i.e. Li-ion batteries, Diesel) was monitored and compared to each other. The heat-release rate and emission of (toxic) substances was measured, and different fire-fighting methods were applied during each test.This paper will focus on the aspect of full-scale fire tests of passenger cars performed in a road tunnel. It should be emphasized that the battery-electric vehicle fire tests presented here were the first of their kind under real road tunnel conditions. This concerns the fire behaviour, but also some new approaches to fighting a BEV fire. All previous tests reported in journals were either carried out in fire halls or only concerned individual battery modules.

Simulation of Large-Scale Tunnel Belt Fire and Smoke Characteristics under a Water Curtain System Based on CFD.

Transport belt fires pose a serious threat to the lives of miners. The smoke spread characteristics of transport belt fires are important for the effective construction of underground safety works. In this paper, a water curtain system is added to ventilation to investigate the effectiveness of water spray in blocking fire-induced smoke and heat. Using computational fluid dynamics (CFD) simulations obtained with FDS 6.0.1, full-scale underground belt transport tunnel fire tests are conducted with mechanical ventilation and a water curtain system to obtain smoke spread characteristics, temperature distribution, visibility profiles, and CO distribution. The results show that the addition of a water curtain system can effectively limit temperature and smoke, but high mechanical ventilation velocities are not conducive to the water curtain system, limiting underground tunnel fires. This study found that the mechanical ventilation velocity should be controlled at approximately 0.8 m/s when the water curtain system is on a 100 m beltway. Smoke across the water curtain system area, smoke stratification in the lower layer of the water curtain area is lost, the water curtain system in the lower layer of the tunnel will affect the flow field and temperature field flowing to the fire source, and the blockage effect is the most obvious in the upper layer of the tunnel. The water curtain system reduces the distribution of temperature and CO concentration in the tunnel and rapidly restores visibility. With the addition of the water curtain system, the environment in the restricted area is suitable for occupant evacuation and firefighting, and the system can be considered a viable strategy for tunnel smoke control.

Numerical modelling of LSF walls under combined compression and bending actions and fire conditions

Numerical modelling of cold-formed steel walls used in determining the ambient temperature ultimate capacities has evolved from the use of idealised stud-only models to advanced models by employing sheathing and connection characteristics. Due to the convergence issues associated with elevated temperature structural models, attempts to incorporate sheathing are scarcely seen in the literature. In this study, the behaviour of light gauge steel framed (LSF) walls under combined axial and lateral loads and fire exposure was investigated by using stud-only and advanced structural finite element (FE) models. The advanced model is an improved single stud model which included gypsum plasterboard sheathing while also making models computationally less demanding. It incorporated material and geometric non-linearities, contact interactions, idealised in-plane restraints and explicit modelling of gypsum plasterboard sheathing, and was validated using full-scale fire test results. The predicted fire resistance levels (FRLs), failure modes, axial shortening and lateral deflection plots showed good agreement with fire test results. Furthermore, thermal FE models were also developed and validated against fire test results. They will be extended to obtain the time–temperature profiles of cavity insulated and non-insulated single and double plasterboard sheathed LSF walls exposed to fire for use in structural parametric studies. This paper summarises the findings of this study and proposes suitable recommendations for FE modelling of LSF walls under combined compression and bending actions and fire conditions.

Adaptive modified ant colony optimization algorithm for global temperature perception of the underground tunnel fire

Due to complexity and diversity of the real tunnel structures and fire scenes, there exist few effective methods for temperature prediction of the underground tunnel fire. Hence, here a data-driven adaptive modified ant colony optimization (ACO) algorithm is developed to predict the global temperature field of the underground tunnel fire. The algorithm is not limited to the special tunnel structure and fire scene, in which temperature of the underground tunnel fire can be predicted based solely on some sensor data. Meanwhile, to solve the problem that the choice of the model parameters is usually case by case in the traditional ACO algorithms, the model parameters can be adjusted and determined adaptively in the improved algorithm. A numerical example of full scale fire test of an underground tunnel is used to verify the ability and effectiveness of the developed algorithm. The results show that the maximal error is less than 10%. The developed algorithm can be used to predict global temperature with respect to time of the underground tunnel fire, which is easy to be used in engineering application due to its advantages.

Numerical Investigation on Fire Performance of LSF and Steel Modular Floor Panels

The steel Modular Building Systems (MBSs) that have been influenced by the Light-gauge Steel Frame (LSF) techniques have become a prominent culture in the industry. However, the detrimental behaviour of steel structural components at high temperatures has elevated the risk of fatal accidents in the event of a fire. Although several research investigations have addressed the fire performance of steel modular wall systems, the behaviour of modular floor systems has not been adequately addressed in the state of the art. Hence, to promote the fire safety and optimum design techniques in the modular construction industry by addressing the aforementioned research gap, this study investigated 48 conventional LSF and MBS floors for their structural and insulation Fire Resistance Levels using Finite Element Modelling (FEM) and Heat Transfer Analyses (HTA) techniques. Initially, full-scale experimental fire tests were modelled using FEM methods, and the validity of the techniques was verified prior to the analyses of parametric floor systems. Furthermore, the structural behaviour of the channel section joists in the elevated temperatures was studied, and hence a correlation was established to determine the critical steel temperature at the structural fire failure with respect to the applied Load Ratio (LR). An additional 12.5 mm thick plasterboard sheathing on single plasterboard sheathed floors resulted a 30 min improvement in structural and insulation FRLs. In addition, the modular floor systems demonstrated enhanced structural and insulation Fire Resistance Levels (FRLs) against the corresponding conventional LSF floor designs due to double LSF skin build-up. The incorporation of rockwool insulation and the increase in the insulation volume implied increased structural and fire performances. However, insulation material in the modular designs was more effective. The fire-rated conventional and modular LSF floor systems are expected to be practised in the construction industry to achieve required fire resistances with optimum material usage.