The Proceedings of 11th Asia-Oceania Symposium on Fire Science and Technology

The temperature profile of horizontally oriented jet flame with square fuel source has rarely been investigated in past years; especially, the effect of fuel portal geometry aspect ratio on temperature distribution of horizontally oriented jet flame has little appeared in the previous literature. In order to study the temperature profile of horizontal jet fire, a numerical simulated code was carried out to simulate horizontal jet fire with square fire source and natural gas as fuel. The fuel jet velocity was varied from 27.5 to 205.8 m/s. The temperature distribution features on horizontal and vertical directions were investigated, and the temperature prediction model was amended. The results show that the temperature is influenced by fuel jet velocity heavily. The heat release rate increases linearly with fuel jet velocity, and the slope is 29.1. The horizontal maximum temperature on orifice centerline direction rises from 304.5 to 614.8 °C with fuel jet velocity increase. The predicted model is modified to apply to horizontal jet fire, and the predictions by amended model agree well with simulated data.

This paper presents discussions regarding informal settlement (also known as slums, shantytowns, favelas, etc.) fire dynamics and lessons learnt from full-scale tests on dwellings, typically referred to as “shacks” in South Africa. Smoldering and flaming fire setups are considered, and both timber and representative household contents are used as fuel sources. It is shown that due to the small size of shacks, flashover can be obtained within minutes. Maximum temperatures recorded are typically around, or in excess of, 1000 °C, depending on the fuel and structural configurations. Due to the poor construction methods used for such structures, they can collapse, or walls can open up, meaning that ventilation conditions continuously change and are difficult to accurately define. The presence of flammable wall finishes or drapes has a significant effect on the rate of fire spread and fire behavior, and such flammable finishes are often present in dwellings. Computational fluid dynamic (CFD) software [Fire Dynamics Simulator (FDS)] is utilized to analyze certain tests, which generally shows good correlation. However, due to significant variations in fuel contents, ventilation conditions, structural configurations, and wall finishes, there is a high degree of uncertainty inherent in developing models for such environments. From the work, a greater understanding of fire dynamics in low income, temporary structures (comparable with some refugee camps) can be obtained through which better solutions and interventions can be developed. Recommendations are provided for how to simulate shack fire scenarios in experimental testing more effectively.

Flame thickness is an important parameter in both laminar and turbulent flame studies. To provide some basic understanding of the effect of the fire inhibitor on the laminar flame thickness, numerical calculations of methane–air premixed flames doped by dimethyl methyl phosphonate (DMMP) were conducted. The results show that the flame speed depends highly on the reactions: $$ {\text{HOPO}}_{2} + {\text{H}}_{2} = {\text{PO}}_{2} + {\text{H}}_{2} {\text{O}} $$ ; $$ {\text{PO}}_{2} + {\text{H}} + {\text{M}} = {\text{HOPO}} + {\text{M}} $$ ; $$ {\text{HOPO}} + {\text{OH}} = {\text{PO}}_{ 2} + {\text{H2O}} $$ ; and $$ {\text{HOPO}} + {\text{OH}} = {\text{PO}}_{ 2} + {\text{H}}_{ 2} {\text{O}} $$ The laminar flame thickness increases with the increase of the DMMP addition. The preheat sub-zone in the flame front is more vulnerable to the inhibition effect of DMMP. Based on the opposed-flow flame calculations with different outlet velocities, the results indicate that the preheat sub-zone is more dependent on the local stretch rate than the reaction sub-zone. To figure out the reason why the flames become thicker after DMMP addition, the flames’ chemical structures are extracted and discussed. It is found that the chemical reactions in the flame zone are retarded and the upstream gas flow velocity is artificially reduced to make the flame surface stay in a certain area in the calculation. Accordingly, the residence time of the reactant mixture increases, and the CH2O and OH diffuse and distribute in a wide area. Therefore, the radical-based flame thickness increases with DMMP addition.

We examined the influence of the initial humidity to the flame propagation rate of LPG/air and LPG/O2/N2 mixtures to contribute to the risk assessment of the alternative energies. The ignition chamber was 1.36 L of volume, made by SUS316 steel. The moisture was added to the chamber by introducing air or inert gas which was passed through the bubbler. The ignition was initiated by the electric spark which was generated at the gap of needle electrode. First, we found that the ignition probability of LPG decreased with adding the moisture. On the other hand, we also found that the following three effects simultaneously appeared in the LPG combustion under the presence of moisture; (1) combustion-promoting effect that the unreacted LPG reacts to the O and/or OH radicals which were decomposed from the moisture, (2) combustion-suppressing effect by cooling due to the latent heat and the sensible heat of moisture, and (3) combustion-suppressing effect due to the oxygen insufficient which was caused by adding the moisture. The present experimental results could be explained by the above three effects. Furthermore, we confirmed that the results of chemical equilibrium analysis using CHEMKIN-PRO support the above hypothesis.

Backdraught is an unpredictable and dangerous fire phenomenon, particularly for firefighters during search, rescue and firefighting activities. Most previous research into backdraught has used methane as fuel, leaving many questions unanswered. A series of reduced-scale backdraught experiments have been carried out using solid polypropylene as a fuel source, and conclusions have been drawn correlating the compartment temperatures to the onset of backdraught. It is found that when the maximum temperature in the compartment is above 350 °C when the door is opened, a backdraught can occur by auto-ignition, and no ignition source is required. However, no correlations could be identified with temperatures near the door or near the floor. It was also found that there is a correlation between compartment temperature and backdraught delay time, with cooler compartment temperatures leading to longer delays.

In this study, a set of experiments were carried out in micro- and normal gravities to study the flame shape and oscillation of co-flow laminar diffusion ethylene and propane flames. The experimental results show that in microgravity, the flame length and width are larger than those under normal gravity, and the ratio of flame length to width is lower than that in normal gravity. The flame length and width decrease seriously with the increasing co-flow air velocity in microgravity, while they are almost unaffected by the co-flow air velocity in normal gravity. The flame oscillation is not experimentally noticeable in microgravity. In normal gravity, it is found that the flame oscillation frequency increases linearly with the volume flow rate of co-flow air. The flame oscillation is fully suppressed when the air co-flow velocity exceeds the critical velocity. And, the critical air co-flow velocity increases with the initial fuel flow velocity.

Carbon disulphide (CS2) represents an important chemical commodity, unfortunately, found responsible for several factory, laboratory and transportation fires. This contribution examines the high flammability of CS2 by exploring the fire chemistry of the intersystem crossing (ISC) process that occurs within the two key elementary reactions. By expanding the potential enthalpy surfaces of CS + O2 reaction into three-dimensional space, we reveal the unusual changeover from the triplet surface onto the singlet surface through the ISC point. We calculate the minimum energy crossing point to locate the ISC structure, resulting in a lowered activation energy for the CS2 + O2 and CS + O2 reactions. This enables us to explain the low ignition temperature and high flammability of CS2, a common compound in the chemical industry.

This paper describes a new method for modeling smoke movement within large rooms. The model includes horizontally two-dimensional and three laminar flows including the ceiling jet, reversed flow, and airflow. This model is practical because it can predict three-dimensional temperature distributions of any points in the volume simulations in a short time. For simple validation, predictions delivered by the model are compared to the measurements from fire experiments in a large building. The predicted gas temperature profiles agree qualitatively with the measurement, and then the performance of the model is generally acceptable.

Wind action on the flow behavior of the window plume along the exterior wall of a building was studied by analytical and numerical methods. Heat release rate of fire and outside wind speed were varied in the study. It was found that the window plume would flow downward under side wind. Fire might spread to the room above the window when the wind speed was low. With the wind speed increasing, the plume would be blown to downward direction, giving hazardous conditions to rooms at downstream of the wind. The tilted angle of the window plume was derived by theoretical analysis.

The paper presents a neural-network-based zonal method (RADNNET-ZM) for the analysis of radiative heat transfer in an arbitrary Cartesian enclosure with an isothermal, homogeneous, non-gray medium. The model accounts for the non-gray effect of absorbing species in a combustion environment and the geometric effect of any three-dimensional enclosures. The model is verified against benchmark solutions. Maximum local error is observed to be less than 4%. Prediction accuracy of an existing zonal radiation solver is assessed. Results demonstrate that RADNNET-ZM can provide a substantial improvement to zone fire simulation models for the prediction of radiative heat transfer without a significant increase in computation cost.

The effect of the platform screen door of different types on smoke control of platform fire at a subway station was investigated by numerical simulations. The results show that for ventilation mode only with over tunnel exhaust system activated, the efficiency of the smoke control system is the worst for fire scenario with full-seal platform screen door. In terms of ventilation mode only with the platform exhaust system, there is no obvious difference in the efficiency of the smoke control system for four kinds of the platform screen door, which is the same when the over tunnel exhaust system, the platform exhaust system and the lobby supply system are all activated. However, when the over tunnel exhaust system, the platform exhaust system and the lobby supply system are all activated and doors are closed, the efficiency of the smoke control system will decrease for fire scenario with full-seal platform screen door. This study might provide some referable information for the design of emergency smoke control of platform fire for various kinds of PSD installed.

We conducted a full-scale experiment aimed at gathering useful knowledge for planning staircase pressurization for smoke prevention and exhaust, assuming a seven-story office building. We conducted an experimental study on dynamic pressure effects resulting from the installation of the dynamic pressure control system, confirm pressure variation in staircases resulting from opening doors to vestibules, and also confirm the performance of differential pressure adjustment dampers in staircases. The following results are obtained: 1. When the air inlet and the opened doors are on the same floor, the effect of the dynamic pressure control system is small. When a floor that opening the doors is moved away from the air supplied floor, it shows that installing a dynamic pressure control system reduces the influence of dynamic pressure near air inlet by about 54%. 2. Opening doors both staircases and vestibules did not have a large effect on pressure variation within staircases; rather, pressure conditions within staircases tended to be maintained. 3. To implementing smoke control by staircase pressurization, installing only a single differential pressure adjustment damper in staircases maintains a higher pressure than the setting for differential pressure adjustment damper (60 Pa), possibly obstructing door opening. This study thus provides basic information for planning staircase pressurization aimed at smoke prevention and control.

The ALOHA software was used to calculate the leak source strength of the cryogenic ethylene tank, and the calculation results were provided to the FDS software to set up the model. The study established a basic ethylene tank leakage scenario, and the diffusion process of ethylene was simulated by means of computational fluid dynamics software (FDS), which could describe a series of physical changes in the vapor cloud diffusion process. At the same time, the influence of the relevant steam control technology of setting fire dikes with different height on the downward wind direction of ethylene vapor cloud was simulated. The simulation results show that the control technique really plays a significant role in suppressing the vapor diffusion.

The flow pattern is the one important factor to indicate the vented flow regularity, which is of great significance for understanding and preventing ceiling vented enclosure fires. In this paper, an experimental study on fire-induced flows in a ceiling vented enclosure was carried out. Five pan diameters and six horizontal opening sizes were adopted and measurements included the pressure difference in the top and temperature at the two sides of the opening. The instantaneous flow pattern was recorded by a video camera and laser technique. The purpose was to reveal the fire-induced flow pattern and make a distinguish between these flow patterns. Furthermore, the buoyancy number and the global equivalence ratio were introduced to analyze the fire-induced flow pattern in the ceiling vented enclosure. Through experimental analysis, the flow pattern across the horizontal ceiling vent induced by the real fire was revealed and summarized, which would benefit for studying the ventilation system in the fire risk assessment and firefighting.

The smoke control effect of mechanical pressurization system in the vestibule of the building is studied based on numerical simulation. The diversity of the actual air inlet setting of mechanical pressurization system is considered. The relative position of the air inlet and fire door opening is investigated in our research, which is divided into three cases: directly opposite, diagonally opposite, and perpendicular. The method of numerical simulation is used to study the influence of the relative position of the air inlet and door, as well as the installation heights of the air inlet of the fire-induced smoke prevention system. The smoke control effect in the case of fire and the cold state without fire is compared and analyzed; the setting position of the air inlet is optimized. The conclusion can provide technical references for smoke control design personnel, building fire protection design audit personnel, and the technical codes’ creators of smoke control and fire researchers.

Smoke is the real threat in a fire in an enclosed, underground parking garage. A model of the smoke movement in a basement was simulated using Fire Dynamics Simulator (FDS) 6.0 software. In this paper, the study used a basement model of 60 m (length) × 30 m (width) × 13 m (height) and has three typical floors. Smoke ventilation shafts were provided for the basement. The required ventilation was based on the air changing ten times per hour. Smoke modeling was investigated under different fire scenarios. Well-controlled liquid pool fire with a heat release rate (HRR) of 5, 10, 15, and 20 MW was used as an input parameter. The following parameters were varied: the location of the fire, the presence or absence of sprinklers, the presence or absence of a smoke extraction system, the variation of the quantity of makeup air to be introduced to basement, and the presence or absence of a jet fan and ducting. Simulation shows that the provision of sprinklers is very important to reduce the heat release rate. The ventilation strategy through a mechanical exhaust fans and makeup air fans can be applied to make the time for smoke removal faster. When makeup air is less, the heat release rates from the design fire more than 5 MW cause high temperature in the fire compartment which may cause fatal injury when exposed to human skin. Combination of ventilation fan and jet fan shows good performance to make smoke removal time shorter.

In 2017 in Tokyo, more than thousand occupants of a seven-story office building evacuated due to fire located at an adjacent site. Because the fire did not occur on their own site, the evacuation was spontaneous and, therefore, not performed according to a normal evacuation manual. This paper investigates the human behavior in this evacuation case, especially focusing on the decision-making process. To do this, the authors conducted face-to-face interviews with four people from the organization who made the decision to let employees evacuate and forty-one employees who evacuated. The major findings of the study are: (1) visual observation of fire through windows influences the occupants’ evacuation strategy; (2) occupants tended to postpone leaving the workplace until they received an explicit evacuation cue from others; and (3) multiple occupants chose stairs by taking into consideration that the fire was not in their building. Since the fire compartments had not yet been built and there was no immediate danger to life, these results can also be applied to the evacuation of non-fire floors in a building fire.

Large railway interchange stations with complex geometry are common in contemporary integrated railway networks. Fire evacuation is commonly designed using the timeline analysis in comparing Available Safe Egress Time (ASET) and Required Safe Egress Time (RSET) with agreed scenarios. Smoke management systems are required to achieve longer ASET. Egress time analysis will be evaluated in this paper for a typical large railway interchange. The fire environment was simulated using fire dynamics simulator (FDS), a software based on computational fluid dynamics (CFD). Design fires of 2, 2.5, 5, 10, 25 and 50 MW were used in estimating ASET. Egress simulations by the software SIMULEX were conducted to predict the RSET under passenger loadings of 0.5, 1, 2 and 4 m2/person. The results show that the ASET in most of the cases with higher fire size and with higher passenger loading are less than the RSET. Consequently, the passengers are unsafe in the event of fire evacuation. Therefore, a larger safety margin, defined as the difference between ASET and RSET, should be provided. In the case of low safety margin in some existing stations, fire safety management and procedures on handling fire incidents have to be reformulated properly and carefully.

The single-file movement formed at exit, passageway, and stairway is a common and fundamental phenomenon in building evacuation when fire happened. In order to investigate single-file movement, the controlled experiments contained three parts: acceleration, steady state, and deceleration are effective research methods. In this paper, we conducted single-file movement experiments with two different commands in decelerating phase: (1) normal stop, (2) close stop, i.e., stop at the place as close as possible to the predecessor, in which participants move at different free moving speed. Through rescaling the speed, there is no influence for different free moving speed on speed–distance headway relationship. The linear fitting curve is executed to obtain a quantitative description of the speed–distance headway relation, and the slope in the close stop experiment is larger than that in the normal stop. It is found that there is a little difference in the decelerating phase for different participants and the average close stop distance is 0.34 m, which is a little bigger than average chest width 0.3 m. For the normal stop, the comfortable stop distance is dependent on individual proxemics. In the relation of speed–time, it was divided into two stages, which is fitted using linear regression. The value of negative acceleration in stage I is greater than stage II. Similar to the fitting result of speed–distance headway, participants in close stop experiments have bigger negative acceleration in stage I. However, in stage II, due to the uncertainty of close stop distance for different participants, the value of negative acceleration in close stop is smaller. Actually, in normal conditions, participants stopped with their comfortable stop distance when the predecessor stopped. However, in emergency or hurried conditions, the stop distance would be smaller. Therefore, it is useful to investigate the movement behavior in an emergency (such as fire and earthquake) and hurried conditions when the predecessor stopped suddenly.

In amendment of Building Standards Act of the year 2000, the verification method for evacuation safety was introduced. Knowledge gained in Togawa’s study (1955) is frequently used in this verification method; however, depending on the spatial condition, the estimated results differ from the actual crowd walk nature and this remains a challenge. Considering the situation, this study aims to illustrate the relationship between the spatial condition and crowd walk nature and analyze data gained from the Crowd Evacuation Experiment done in 2015 at Tokyo University of Science. When a corridor includes an opening (a bottleneck) or a merging, a pedestrian crowd will be restrained at the opening/merging. Each part of the bottleneck corridor showed a very similar feature as the merging corridor. Therefore, this study analyzed the bottleneck corridor and merging corridor with a uniform model. These analysis results confirmed the relationship between each part’s density and the ratio of inflow width to the outflow width and showed that specific flow can be calculated from the margin of two densities, regardless of the spatial condition.

The occupants shall evacuate the building through stairs, in case of fire of high-rise building. A number of evacuees may cause the congestion on stairs. This paper focuses on the characteristics of the non-merging evacuation flow, which is the flow consisting only of evacuees descending on the staircase without merging there under flow conditions on the upper floor, which are generated by the merging of persons going down the staircase and entering there. This study used the data obtained in the observational survey on the real evacuation drills repeated annually for three years in the high-rise building. The flow conditions were classified into three groups based on the congestion and the merging of evacuations in the staircase. As a result of this study, the characteristics of the non-merging evacuation flow in each of the three groups were elucidated.

This study was focused on the time gaps between passengers exiting a bus during an evacuation in the event of a tunnel fire. In a tunnel fire, bus passengers must evacuate irrespective of whether the bus is on fire or not. Hence, considering the tunnel fire situation, we considered two scenarios for evacuation: (1) evacuation in which the passengers do not perceive emergency and (2) evacuation in which the passengers perceive emergency. Based on these scenarios, we carried out experiments and observations to measure the time gaps of able-bodied persons and elders with reduced mobility. The experimental results indicated that the time gaps of able-bodied persons ranged from 0.42 to 4.42 s (mean = 1.40 s) and those of simulated elders ranged from 1.8 to 4.73 s (mean = 2.94 s). The probability distribution of experimental time gap data also demonstrated that the maximum rate of the able-bodied person data corresponds to 1.0–1.5 s, and the maximum rate of the simulated elderly data corresponds to 2.0–2.5 s. Moreover, most time gap data were in the 5 s range in both the evacuation experiment and observations. However, in observations, the appearance of particular movement characteristics caused relatively longtime gaps which were even larger than the mean value of simulated elders in the experiment.

The study is an investigation conducted to know the trend of resident’s facility usage. Based on the findings of the investigation, we can learn that the most popular location of an indoor facility for residents was “public activity center,” and the outdoor facility was “park.” Besides, most residents chose “Fellowship” as their usage purpose and 3 times for 1 week was the frequency which most residents chose. When it comes to the problem of facility usage, most problems were focused on hardware problem relating to the inadequacy of equipment for an activity. In order to make residents get familiar with public facilities, the drill of disaster prevention should be designed to get fellowship with residents. Moreover, schools, which are designated shelter in a disaster, should be open to the nearby community.

This paper provides tests on Tandem Prusik, and two mechanical devices as load-limiting device. The test results on a 3-wrap Prusik demonstrated that it would eventually break when overloaded, which contradicts to popular traditional belief that it will not continuously hold and substantially slip on rope if overloaded. The same tests conducted on mechanical devices show results of a positive maximum static slip of about 600 kgf, above which the rope will substantially slip to maintain the tension force even with further pulling above this limit. This novel finding is critical as it provides sound indication that the device would automatically make adjustments for the tension to be kept safe in the safe zone in field operations.

By introducing toxicity coefficient to the static force field and pheromone model to the dynamic force field, an improved cellular automata evacuation model (ICAEM) is developed. Evacuation experiments in an 11 m × 8 m classroom are carried out, the time from their initial position to the single exit or double exits of the classroom and the stagnation time near the exits are recorded and compared with the simulation results to validate the ICAEM model, to check the influencing factors of the exit position KS, the repulsive coefficient KR, and the pheromone damping coefficient ρ in the model. The results show that when the pheromone damping coefficient ρ = 0.5, the self-lining phenomenon is significant. If KS = 1, KR = 0.12, the simulation result is very consistent with the actual evacuation time in the experimental tests. Finally, the ICAEM model is applied in a 118 m × 36 m twenty-first-century subway station platform where there are a total of 2500 persons from two trains waiting for evacuation. The simulation error is reasonable comparing with the calculation results by engineering design code of PRC and the Togawa’s formula. It is found that the original layout of EXIT 2 obstructed the evacuation flow of the station platform at a certain degree, resulting in bidirectional counter flow and stagnation near the exit. After improving the layout of the EXIT 2 on the platform based on the simulation results by ICAEM, the RSET of the whole platform is shortened and the stagnation phenomenon is attenuated. The ICAEM model is applicable and meaningful to the crowd evacuation and performance-based safety design in high densely populated public places.

Building fires have accounted for 74% of all fire disasters in Taiwan. The local government needs a quantitative analysis approach for analyzing the probability of fire. This study adopted the analytic hierarchy process (AHP) to assess probability of fire in 17 villages comprising in an administrative district in New Taipei City, Taiwan. A total of 5 assessment items and 18 assessment indices were comprised for fire probability. The weights were collated into a matrix in order to evaluate fire probability of ratings. The yearly average building fires and the average fire-affected area during 2005–2015 were used to verify the proposed approach. The data of fire were obtained from government databases. The findings obtained can facilitate assessments of fire probability and can also provide reference for building fire-prevention strategies. This study proposes an approach for probability of fire.

The main purpose of this study is to investigate on finding factors significantly affecting life casualties in building fires and constructing explanatory models for prediction. Factors were firstly generalized from literature review, and then an empirical study using data from fire cases during 2015 to June 2017 in New Taipei City was conducted. Chi-square test and t-test were performed later on to screen out factors closely related to life casualties, and those factors were then put into binary logistic regression analysis stepwise subsequently. The statistically significant variables in the three convergent models (human factors group, ignited and building environmental factors group, and built-in fire safety measures, rescue and fire growth factors group) were physical and mental illness, state of consciousness, horizontal fire compartment, narrow alleys, building structure, fire phases, and hydrant separately. By using the proposed binary logistic models, the overall correct classification rates were up to 81.5, 81.6, and 70.4%, respectively. Ultimately, the study provides suggestion in law enforcement, public education, and fire prevention planning.

Approximately, one billion people across the globe are currently living in informal shack settlements with a large potential fire risk. Due to the small distance between shacks, a single shack fire may spread and could cause a large area of informal settlement to be burnt in a short period of time. In this work, the critical fire separation distance between shacks is first discussed and determined using a simple physics-based theoretical model. Aerial photography within geographic information systems (GIS) is then employed to verify the calculated results based on a real informal settlement burn scar in Masiphumelele, Cape Town, South Africa. The radiative heat fluxes along the centerline of the shack window, at different distances, are calculated to estimate the ignition potential of combustible materials in adjacent shacks. Meanwhile, the potential fire risks, assuming separation distance as a proxy for risk, pre- and post- a known fire in Masiphumelele are obtained and compared. It was established that the heat flux would decay from around 100 kW/m2 within 0.5 m to the value smaller than 0.1 kW/m2 at the distance of 3.5 m away from the shack, which can be considered as a relatively safe distance. The theoretical result agrees well with the minimum effective distance of 3.3 m in real fires occurred in Masiphumelele. However, a GIS analysis of the informal settlement layout in 2015 and 2017 demonstrates that, if the critical fire separation distance is more than 3.0 m, 97% of the settlement could be at risk in a single fire incident. Therefore, more research is required to improve the understanding of fire spread mechanisms in informal settlements.

Wildfires are one of the major serious disasters all over the world. The technology of satellite remote sensing provides useful data for post-fire assessment. This study aimed to investigate the optimal spectral indices for mapping post-fire-burned area. We acquired the post-fire data of Moderate Resolution Imaging Spectroradiometer (MODIS) sensor over several wildfires in boreal forest in western America, 2016. Then, we adopted empirical formula and multi-threshold method to extract the sample sets of five types (burned area, vegetation, cloud, bare soil, and shadow). The separability of spectral indices between burned area and other four types was analyzed by separability index M. Based on the spectral characteristic analysis of burned area, the value of separability index M of the six spectral indices (VI, CSI, MIRBI, NBR, NSEv1, and NSTv1) is larger than 1.0, which indicates that these indices perform well in discriminating burned area and unburned types, and NIR (0.841–0.876 μm), SWIR (2.105–2.155 μm) spectral domain, emissivity of thermal infrared band and land surface temperature are also proved to be sensitive to burned area. The optimal spectral indices obtained in this paper can be integrated into the burned area detection algorithm in further research.

To assess fire hazards of gearbox oil and transformer oil applied in the nacelle of a wind turbine, the reaction-to-fire properties prior to combustion should be addressed. Gearbox oil and transformer oil were studied by using cone calorimeter exposed to external radiant heat flux levels of 15, 25, 35, 50, and 75 kW/m2. Potential fire scenarios in which liquid oils contribute to the fire spread areas and fire intensities were designed and proposed. The reaction-to-fire properties of such oils are researched from two aspects of thermal hazard and nonthermal hazard. And the critical thermal radiant flux $$ (q_{\text{cr}}^{{\prime \prime }} ) $$ and the time of ignition $$ (t_{\text{ig}} ) $$ were obtained by the conical calorimeter, and the ignition characteristic was analyzed. Results show that based on the analysis of PKHRR and THR, the reaction of fire properties of the transformer oil is higher than gearbox oil, and based on the analysis of PKSEA, PKRSR, and TER, the gearbox oil is higher than transformer oil. In the same radiant heat flux, based on PKHRR and THR to determine the liquid oil fire hazard rankings are: transformer oil > gearbox oil; based on PKSEA and TSR to determine the fire hazard ranking are: gearbox oil > transformer oil. The critical radiant heat flux of gearbox oil and transformer oil is 9.23 and 6.43 kW/m2 when the radiant heat flux is 15 kW/m2. The same liquid oils have the least ignition time and the larger fire hazards when the radiant heat flux is 75 kW/m2.

Building Standard Law (BSL) of Japan requires a building to maintain certain fire safety performance on preventing building-to-building fire spread in urban area. The level of requirement on a building changes with the site location, total floor area, and number of floors of the building, though in a prescriptive manner. In this study, a prototype of risk assessment method is developed for the performance-based fire safety design of a building in regard to building-to-building fire spread prevention. The fire spread risk of a building is evaluated by an event tree analysis in which occurrence probability of fire spread is considered as the probability of successive occurrence of comprising probabilistic events. The probability of each event is represented as a function of fire-resistive time of building members and fire duration time. For the consideration to maintaining continuity from the existing building regulation to an alternative building regulation, equivalency of the requirement level of the two building regulations is validated by comparing the fire spread risk of a building that can be built under each regulation. A case study was performed with a building located in the fire protection zone (FPZ). The result showed that there are several combinations of design parameters such as the fire-resistive times of exterior wall and opening that satisfy equivalent level of the requirement in terms of the fire spread risk in addition to the ones prescribed in the existing regulation.

This project examines the thermal protective performance of firefighters’ garment. Although this research topic has been rigorously studied to secure the safety of wearers, little information exists on the clothing’s behaviour at ‘recent’ environments created by compartment fires beyond the flashover state; the critical conditions become more severe due to increases in use of synthetic materials in furnishings and construction. As part of the project, this paper discusses particularly (i) the quantification of the current critical fire hazards; (ii) a sequential development of apparatuses capable of generating the heat flux defined, from bench-scale to human adult-scale; and (iii) the establishment of a measurement system incorporating a skin simulant. To represent the up-to-date severity of fires, the upper bound (126 kW/m²) of the conventional range of flash fires is employed rather than the standard (84 kW/m²), as the worst-case scenario for fire attack teams. Heaters are systematically advanced and calibrated with respect to the ability to emit, spatial uniformity of irradiance, and its temporal consistency. A measurement plan for testing is established in association with the actual physical damage to wearers (i.e. superficial second-degree burn injury). A skin simulant which exhibits thermo-physical characteristics similar to those of human tissues is also developed to make a sensor which intends to accurately predict burn injuries and thus assess the performance of garments. This work tends to create an advanced testing environment for thermal protective clothing, and therefore will contribute (i) to the full understanding of the garments’ behaviours under critical conditions, (ii) to the improvement of the potential shield-like barrier’s protective performance, and thereby (iii) to the security of the health and life of firefighters, in due course.

Firefighters often work in harsh high-temperature and high-humidity environments such as scene of fires. Additionally, the heat and perspiration generated by the human bodies further increase the temperature and humidity inside the fire-protective clothing. The aim of this research is to scientifically evaluate the body load based on vital data from firefighters according to the activities and environment of each firefighter and to further investigate the effect of cooling the human body by fluid intake with the aim of lowering the risk of heatstroke. In a series of experiments, six firefighters took exercise in an environment of 25 and 40 °C as a normal-temperature and a high-temperature condition, respectively. And they took in water or ice slurry before and after exercise. As the experimental result, in case of exercise in the high-temperature environment, intake of ice slurry caused rectal temperature to decrease rapidly compared with intake of water. But in the normal temperature, the cooling effect of rectal temperature by intake of ice slurry showed little difference from ingestion of water. The ear temperature did not show the difference by intake of water and ice slurry both; in addition, after the exercise 1, during rest time with intake of water, the ear temperature decreased to initial temperature at the normal-temperature and high-temperature environment. The trends of cardiac rate looked almost identical between intake of water and ice slurry in each environment for exercise, but after only the exercise 1, intake of ice slurry could decrease cardiac rate to initial condition earlier than intake of water. As a result of this research, ingestion of ice slurry was shown to be effective at reducing the rectal and body surface temperatures during rest after exercise in the high-temperature environment and slowing the heart rate during rest after exercise in both the normal- and the high-temperature environments.

As a widely used protection device, the radiation blockage ability of water spray curtain to high temperature heat source is influenced by a number of elements, of which spray dynamics characteristic of nozzles is an important factor. An experimental study on radiation attenuation ability of water sprays has been carried out in laboratory. Droplets diameters and distributions of varied positions have been measured by laser particle sizer at different pressures. The position range varies from 25 to 175 cm and pressure changes from 1 to 3 bars. The attenuated radiation fluxes are measured by radiation heat flux meters to analyze the transmissivity of sprays. The results clearly indicate that the spray dynamic characteristic can severely affect the blockage ability of thermal radiation. The variation tendency of particle mean diameter can directly reflect the change trend of attenuation efficiency. Characteristic of droplets and relative positions of protected objects are two significant factors for affecting attenuation efficiency. These factors should be considered when water spray curtains are to be used in industrial and building fire protection. Furthermore, different nozzles with different characteristics, which should be measured firstly when they are used to discharge the water sprays.

In case of fire, reinforced concrete floor slabs are heated on the lower surface and are deflected due to the temperature gradient along the thickness direction and the reduction in strength at elevated temperature. In accordance with the deflection of the floor slab, the membrane stress developed and caused the enhancement of load-bearing capacity. This paper discussed, in the basis of the results of high-temperature loading tests of small-scale reinforced mortal slabs, the amount of deflection due to the temperature gradient and the influence of the bottom reinforcement temperature on the maximum strength, and the enhancement factor. The parameters include the support conditions and the steel temperature at the bottom reinforcement. The thermal deflection of the two-way slab due to the temperature gradient approximately agreed with the theoretical value of the one-way slab. The maximum load-bearing capacity in case of the bottom reinforcement temperature of 400 °C was equal to or larger than that at room temperature. The decrease in the maximum strength above 500 °C was lower for the two-way slabs than for the one-way slabs. The enhancement of the maximum strength due to tensile membrane action was confirmed from the test result without punching shear failure.

This paper presents a new test method to investigate the influence of fire damage on stiffness, strength, toughness in macro-view and localization of micro-crack in micro-view of concrete by conducting uniaxial compressive test associated with acoustic emission (AE) after specimen subjected to heating with different thermos-conditions such as the rate of heating, maximum temperature, exposure time, as well as cooling condition. During the testing, the extensometer was used as feedback signal control to stabilize crack growth; the complete loading curve including pre- and post-peak stage was then obtained. Therefore, the evolution of AE microseismic sources with respect to loading process was also examined. The test results in macro-view show that the stiffness, strength, and toughness decrease with an increase in maximum temperature; the post-peak behavior from snapback (Class II) converts to snap through (Class I) at maximum temperature ranged 200–400 °C, whereas, in micro-view, the AE localization occurred earlier as the maximum temperature increased. When the maximum temperature reached 600 °C, the AE localization cannot be found during the uniaxial compressive test.

Multi-walled carbon nanotubes (CNTs) were introduced into the structure of phosphate ester (PEA) to prepare a series of novel flame retardants named PEA-functionalized CNTs (CPEAs). The chemical structures of CPEAs were carefully characterized by Fourier transform infrared (FTIR) spectroscopy and 1H nuclear magnetic resonance (1H NMR) spectroscopy. Then, the obtained PEA and CPEAs were mixed with amino resin to produce five kinds of fire-retardant coatings applied on plywood boards. The optical transparency, fire protection performance, and thermal behavior of the transparent coatings were investigated by various analytical methods. The optical transparency analysis shows that the transparency value of coatings gradually decreases with increasing CNTs contents, and a small amount of CNTs imparts a high degree of transparency to the resulting coatings. The results from the flammability tests indicate that the CPEAs impart lower weight loss, char index, flame spread rating, heat release rate, and total heat release to the resulting coatings than those of PEA. The thermo-gravimetric analysis reveals that the CPEAs possess higher thermal stability and residual weight to the resulting coatings compared to PEA. Char residue analysis indicates that the introduction of CNTs is beneficial to generate more P–N–C and P–O–C cross-linked structures in the condensed phase that form a high-quality intumescent char against heat and mass transfer, thus effectively improving the flame retardancy and thermal stability of the transparent coatings.

In performance-based structural fire safety design, various calculation models are used to predict the structural behaviors of building elements exposed to fire. Although many of such calculation models require material properties of building elements as input data, it is often difficult, technically and economically, to obtain such material properties. A potential and practicable alternative is to make use a method to translate the fire duration in arbitrary compartment fire conditions to the equivalent fire resistance time of the existing standard fire furnace testing. This paper aims to develop a method for translating the duration of ventilation-controlled compartment fires to equivalent fire resistance time in the standard fire test. The method includes a simple calculation model integrating the radiation heat loss through window openings as well as the heat losses to compartment boundary and fuel and by ventilation. The translation formula is based on the premise that fire-resistant performance is assessed by prescribed temperature criteria. Example calculation results for equivalent fire resistance time are demonstrated. By this translation method, the fire resistance capability of building elements can be assessed without requiring their thermal properties.

To estimate the fire load of a room, data pertaining to the combustion behavior and other aspects are required. In this study, the fire behavior of diverse printers was observed by conducting a series of combustion experiments. Twelve units of printers were used for the experiments. The weight of the printers ranged between 6.7 and 54.5 kg. The bulk volume was 0.026–0.147 m3. The projected area was between 0.49 and 1.33 m2. The ignition source was a propane gas burner using a 10-mm-diameter copper pipe. The supply flow rate of the gas was set to 1 L/min using a mass flow controller. In the burning test, the heat release rate was measured by using the oxygen consumption method, and the weight change was measured by using a set of load cells. The results of the burning test showed that the combustion behavior and the heat of combustion differed significantly according to the type of printers. The heat of combustion of the inkjet printer was 31.7 MJ/kg and that of the laser printer was 24.7 MJ/kg. The fire load was estimated using the measured HRR and the residual weight after the burning test. The relationship between the initial weight or bulk volume and the fire load is shown. Additionally, the relationships between the surface area and the maximum heat release rate and that between the bulk density and the fire growth rate α are shown. The results of this study revealed that the maximum heat release rate is proportional to the nominal ventilation factor and that the fire growth rate is decreased as the bulk density is increased.

Different from concrete and steel, window glass or glass façade breaks very easily when subjected to a compartment fire. The new vent created by the glass fallout may cause fire spread out and fresh air entrance which can markedly change the enclosure fire dynamics. Nowadays, different types of glazing, such as clear, coated, ground and multi-pane glazing, are increasingly employed in newly constructed buildings. However, very little is known about their fire risk, especially the comprehensive comparison between them is yet to be investigated. In this paper, the fire resistance comparison of different types of glazing is conducted based on the author’s very recent and ongoing experimental results. Literature works of other researchers are also presented for comparison. Additionally, fire safety design and recommendation of glass in buildings are discussed in detail. This research is proposed to provide valuable references for the fire safety performance-based design of glass façades in high-rise buildings.

Most building materials more or less contain moisture. It is often observed at temperature measurements at fire resistance tests and also at numerical calculations of heat conduction in walls containing moisture that the temperature rises stagnate around 100 °C for some time periods. This temperature stagnation significantly contributes to the high fire resistance performance of some types of wall, e.g., gypsum board. In this paper, the existing moisture evaporation rate formula has been revisited and re-examined the heat continuity equation from the standpoint of the existence of heat loss not only for moisture evaporation but also by raising the temperature of the wall. It reduces the number of uncertainties in the heat continuity equation and allows us to skip the step of regression fits to numerical simulation. The new formula is compared to the numerical calculation, and the range of application is validated.

To examine the effect of thermal feedback during a fire in a compartment, flexible polyurethane slab was burnt in an open environment and in a model-scale room. The size of the slab was 500 × 500 mm. The thickness was varied between 50 and 200 mm. The size of model-scale room was 900 × 1700 mm in plan area. Opening height was changed in the range of 200–800 mm to examine the effect of ventilation and smoke layer thickness. The ceiling height was varied in the range of 400–800 mm to examine the effect of extended flame under ceiling. The polyurethane slab was ignited at the center of top surface. Spread of flame was observed and recorded by video cameras. Mass loss rate, temperature profile, and heat fluxes to ceiling and floor were measured. Experimental results show that the thermal feedback effect is clearly observed even in the case of high ceiling with large openings. As the opening height was reduced, the effect of thermal feedback was increased moderately. At maximum, the heat release rate was increased to 170% of that in open burning. The effect of ceiling height was nonlinear. As the ceiling height was decreased comparable to continuous flame height, heat release rate was greatly increased due to the thermal feedback from extended flame under ceiling. Using the measured data, the effect of thermal feedback was correlated with heat flux to floor. Empirical relationships between ceiling height and fire growth rate, between maximum heat release rate and burning type index were derived.

Experiments were conducted to measure effective diffusion coefficients of carbon monoxide through unpainted and painted gypsum wallboard samples. The results show carbon monoxide readily diffusions through gypsum wallboard while application of paint to one surface was shown to have almost no effect, a few percent decreases in the effective diffusion coefficient, to a dramatic reduction in carbon monoxide diffusion, up to 55-fold decrease in the effective diffusion coefficient for samples with two coats of one house paint. All three paints examined were flat-finish, latex-based interior house paints; clearly, the paint chemical formulation affects gas permeability and hence the effective diffusion coefficient for painted surfaces. Two full-scale experiments were conducted in a 11.0 m by 7.3 m by 3.7 m high sealed compartment fabricated with one layer of either unpainted or painted gypsum wallboard on the walls and ceiling. In each experiment, carbon monoxide was released in the compartment, and after the release, the decay of the carbon monoxide concentration was recorded. Over a five-hour period, the painted walls and ceiling experiment’s carbon monoxide concentration slightly lagged the unpainted walls and ceiling experiment’s measurements which is consistent with the effective diffusion coefficient measurements of the unpainted and painted wallboard samples. The implications for life safety assessment compel one to conservatively assume carbon monoxide diffusion through gypsum wallboard progresses at the higher rate commensurate with an unpainted surface unless specific data is gathered. In full-scale fire experiments with conventional gypsum wallboard construction effects of carbon monoxide diffusion should be considered where carbon monoxide measurements are made.

Considerable amount of experiments regarding smoldering combustion of peat had been conducted through various methods of experiment, modeling, and field study, with factors affecting the smoldering combustion of peatlands include: moisture content, density, porosity, wind speed, etc. However, it can be seen that some researches that focus on the influence of moisture content did not consider the evaporation and drying stages of the smoldering front; thus, the parameters of the test results were determined based on initial moisture content prior to combustion. This experiment was conducted in order to study the smoldering combustion of the peat layer which resembles the real conditions in the field, which involves the stages of preheating, evaporation, drying, pyrolysis, and char oxidation. Varying values of moisture content, increasing with depth, were prepared by drying the raw peat sample (sampling results) at 105 °C for 4, 8, 12, 16, 20, and 24 h. The resulting samples were then placed inside a reactor measuring 10 cm × 10 cm with depth of 20 cm, with each layer of peat with different moisture content at 2.5 cm thick; thus, obtaining a layered peat configuration with the dry peat layer on the surface (MC ~8.5%) and the wet peat layer (raw peat) at the bottom of the reactor. Measurements of smoldering spread, evaporation rate, and mass loss (including evaporation rate) were gathered through instruments of thermocouple, soil moisture sensor, and weight balance, respectively, in real time. The results from the experiment suggested that the evaporation rate, smoldering propagation, and depth of burn depended on the thickness of the burnable dry peat layer, or equivalent to the available amount of heat, which will be partially transferred (converted) for heating, evaporation, pyrolysis, and combustion processes. Therefore, smoldering cannot propagate on the moist peat layer because it will always start with evaporation and drying process. The smoldering front will always be bordered by dry peat layer up to the point where the heat generated is equal or less than the amount needed for evaporation, which is the critical point of extinction.

Pyrolysis kinetic analysis of forest combustible material plays an important role in modeling wildland fire. For the kinetic analysis method by using optimization calculations, there is a lack of a reliable method to determine the search ranges of the parameters. This work presents an effort for this problem, for which we propose a comprehensive method by the combined use of the Kissinger method, the model-free methods and a two-point method. For the comprehensive method, the Kissinger method is used to preliminarily evaluate the activation energy of the reaction steps corresponding to the DTG peaks, the model-free methods are used to compare the activation energy values for different pseudo-components, while the two-point method is used to preliminarily evaluate the lower limits of activation energy and pre-exponential factor for the first reaction step. By using this comprehensive method, reasonable search ranges of the activation energy and pre-exponential factor can be determined for optimization calculations. The thermogravimetric experimental data of pine bark at heating rates of 10, 15, 20, and 25 K/min under nitrogen atmosphere are used to check the reliability of the comprehensive method. The genetic algorithm (GA) method is used for optimization calculations. The results show that by the comprehensive method, the GA calculation performs more efficiently than the calculation by using blind range. In addition, if a part of the parameter range is improper, the search range can be further narrowed based on the comprehensive method.

Pipelines are one of the most popular and effective ways of transporting oil, so the safety planning of the oil pipeline is very important. This paper has constructed a set of procedures and indicators for quantitative risk analysis (QRA) of pipelines. The pipeline integrity management method and QRA to construct a theoretical system for pipeline regional safety planning is combined. The system is used to assess the risk of a pipeline in a region, and the calculation results show that the individual risk level of the pipeline in the region is 1.00E–06, which is lower than the standard value 3.00E–06. Therefore, the individual risk of the pipeline’s internal and external protection targets is acceptable. The social risk results show that the social risk curve of the pipe section is in an acceptable area and meets the social risk standard. This approach, which is combined with Chinese risk-acceptable criteria, is not only instructive for the safety planning of the protection targets around the oil pipeline, but also has important reference value for the new site selection, reconstruction, and the development of the surrounding land.

The suppression efficiency of water mist with potassium salts additives on liquid pool fire is experimentally studied in an enclosed space. The penetration pool fire ratio (PPFR) has been utilized to investigate the penetration capability of water mist directly above a pool fire source. The PPFR is generated experimentally by measuring the water mass within the corresponding extinguishing time in the absence of a fire, and a critical PPFR range 40–45% is present, which means more than 45% droplets of water mist arrive at the fuel surface is the essential conditions for additives exerting a chemical effect. The suppression efficiency could be generally sorted in an order of KNO3 ≈ K2C2O4 > K3PO4 ≈ pure water. The chemical mechanism of potassium additives is due to the active substances KOH and KxOy formed at high temperature, and the enhancement effect of CO generated by K2C2O4 thermal decomposition under the volume of enclosed space is far greater than fire source can be ignored. All of the results indicate that the addition of potassium salts can improve the extinguishing efficiency of water mist on liquid fire, and the suppression mechanism is considered due to the combination of physical and chemical action.

Fire and explosion risks of electric vehicles caused by thermal runaway (TR) of battery have become the main obstacle that delaying the popularization of electric vehicles. Usually, the whole battery pack is completely burned down and destroyed, firstly caused by TR of a single battery, and then by the propagation over the whole battery pack with an extremely rapid rate. In this work, thermal runaway propagation characteristics of lithium ion battery module induced by thermal abuses in enclosure space were experimentally investigated. The results indicated that a temperature rise of 72 °C on the nearby battery was found when overheating one cell in the module with an initial temperature of 25 °C; however, no TR occurred. While for the case of overheating the whole battery module, cells were found to TR in 85 s and thus giving rise to a high temperature of 956 °C, as soon as TR firstly happened in the battery module. Violent explosion and high heat releasing rate were observed and eventually caused the damage of battery module. Therefore, the methods of mitigation of TR propagation when TR occurred in modules will become the focus of future research on the safety of lithium ion battery.

Boilover is the most dangerous occurrence in oil tank fires because it expands the burning field and may hurt firefighters by flame or severe radiant exposure. Because of the low density and cost of perlites, this study uses floating perlites on the surface of burning oil to study whether they can delay the occurrence of large-scale boilover and consequently prevent the flame enlargement. The experiment is performed in a round stainless steel pan with a diameter of 1 m and depth of 0.2 m, containing a 0.08 m layer of thick crude oil was used as fuel, above 0.07 m water. Zero, 1, and 2 layers of perlites are placed above the fuel to investigate their effects. Experimental results show that boilover does not occur after using the perlites, while it does occur in the experiment without perlites test. The use of the perlites can reduce the heat flux of radiation and the flame enlargement when boilover occurs, thus enhancing the fire safety of oil tanks and decreasing the risk of firefighting.

The production of firebrands during large outdoor fires remains unresolved in spite of many advances in the fire safety science discipline. To better grasp this complex problem, multiple experiments were undertaken using full-scale re-entrant corner assemblies exposed to wind in order to sample firebrands. In prior work, an ignition methodology was developed to generate firebrands from re-entrant corner assemblies constructed of wood studs and oriented strand board (OSB) as the base sheathing material. The objective of this study was to apply this same ignition methodology to examine if the base sheathing material, namely plywood as compared to OSB, greatly impacted the firebrand generation from re-entrant corner assembly combustion. It was interesting to observe that plywood generally produced far greater numbers of smaller firebrands (within size class up to 0.9 cm2), whereas OSB produced a great number of firebrands in the size class from 3.61 to 14.4 cm2. It is believed that these differences may be related to the different nature of the production process of these materials. Plywood firebrands clearly showed the presence of veneers, whereas the OSB firebrands show the wood strands still compressed together, suggesting a potential useful inspection methodology for post-fire damage assessment to identify the source of firebrands.

The downslope fire spread is one of the typical wildfire spread phenomena but has attracted less attention during the past wildfire research. In our prior work (Fire Technology, 2018, https://doi.org/10.1007/s10694-018-0740-0 ), downslope fire spread over thermally thin fuel bed was investigated. However, if the fuel bed was thermally thick, the combustion interface inside the fuel bed would be different and therefore could affect the heat transfer process. This work investigated the downslope fire spread over thermally thick fuel bed. The experiments were conducted by using pine needle fuel beds with 1.2 kg/m2 fuel load and the slopes of −30°, −20°, −10°, 0°, and 10°. The combustion interface shape was identified from the temperature profiles of five vertical thermocouples inside the fuel bed and found to tilt backward from the vertical direction of the fuel bed for all slopes, indicating the fuel bed was thermally thick. Experimental results showed that the rate of spread (ROS) decreased firstly and then increased from 10° to −30°, same as that reported in the literature and in our prior work for thermally thin fuel bed. Based on experimental observations, a two-dimensional model of energy balance valid for thermally thick fuel bed was developed. The prediction revealed that the fuel is heated mainly by flame radiation throughout the whole process but the combustion zone radiation plays more important role in the near flame region, which is similar with that reported for thermally thin fuel bed in our prior work.

Wildfires are very often difficult to prevent and represent a grave risk; real-time prediction of fire propagation has a vital significance for setting up preventive measures and formulating emergency response plans. However, due to the limitation of computer computation capability, changing of the fire environment and model errors caused by the deficiency of the existed fire simulation tool, current fire models lack the ability to provide considered the accurate prediction of wildfire propagation faster than real-time. Moreover, in the case of the hindrance of heavy smoke, the satellite-based remote sensing or unmanned aerial vehicle (UAV) is incapable of acquiring precise flame front observation data within a certain level of uncertainties. Data assimilation (DA) is extensively functioned in complex predicting problems. And the Ensemble Kalman Filter (EnKF) is one of the best ways of solving large-scale and nonlinear problems, while the computational time is comparatively less than other DA methods. In the present study, real-time prediction of wildfire propagation method is presented by connecting EnKF method and the FARSITE fire area simulator, for updating the dynamically evolving fireline position of a spreading wildfire. The results show that the wildfires forecast are improved with the proposed data-driven methodology than with the stand-alone FARSITE model and successively responsible for an adjusted prediction of the wildfire spread.

Roll-paper storage is one of the most challenging hazards for fire protection. This work studies the fire behavior of hard surface roll paper with different paper basis weights (i.e., area density) and inert content. Intermediate-scale tests were conducted including both free-burn tests and water suppression tests using the water application apparatus (WAA). The measured heat release rates (HRRs) and applied water fluxes were analyzed to calculate the critical delivered flux (CDF) for the selected papers. The test results showed that roll paper with a larger area density or a higher inert content generally has a lower fire growth rate and a lower CDF. A roll paper density parameter is proposed to reflect the impact of both the paper basis weight and inert content. This parameter shows consistent correlations with fire growth and suppression and thus can be recommended as a means of roll paper classification for fire protection.

Water application has been used widely and considered as one of the most reliable fire extinguisher systems. Although Actual Delivered Density (ADD) is a vital property to evaluate its performance that fire can be suppressed when the value of ADD is higher than that of Required Delivered Density (RDD). It is still unclear how to accurately estimate the amount of water penetrated through flames, which is essential to calculate ADD. The purpose of this study is to assess the influential factors of ADD and to establish proper evaluation criteria of water application. To this end, a series of experiments were conducted to measure the effects of a fire source on the amount of spraying water delivered by water application. The variable parameters include the type of head, the height between head and fire source (later, spraying height), the dimensions of the fire source, and the heat release rate. The experimental results show that the spraying height and the nozzle characteristics can dramatically influence the water penetration ratio. Furthermore, when JJXP060 was within 0.5 m spraying height, the ADDs were significantly affected by the scale of the fire source. Large-scale fire source scenarios were also simulated using Fire Dynamics Simulator (FDS). It shows that the ratio of the ADD with a fire source to the ADD without a fire source, directly below a nozzle at 3 m height, is within 10%, and its value does not decrease as the scale of fire increases. Lastly, a simple predictive model was calibrated experimentally, which can serve as a tool to estimate the amount of water penetrated through flames.

Experimental study was conducted to examine the possibility of common-use temperature sensors to apply to early fire detection. In the series of experiments, the velocity of air-conditioning flow and the HRR of a fire source were varied to investigate the ceiling jet behavior and temperature sensor response which is relatively slow compared with ordinary heat detectors. As a result, it was found that a small fire can be detected by common-use temperature sensors by considering the arrangement. Also, the estimation method of sensor response was discussed. The sensor response can be estimated for even a very small fire in the early stage of fire by combining the prediction formulae for ceiling jet flow and for the thermal response of sensors. The influence of air-conditioning airflow was also investigated by the experiments and CFD simulations. It was confirmed that weak ceiling jet induced by a small fire cannot approach to the airflow outlet due to the obstruction by air-conditioning flow. When considering the arrangement of temperature sensors, the sensors should be located at least 1.0 m away from the air-conditioning outlets.

This study presents the modeling progress for water mist suppression of deep-seated solid fuel fires in a rack-storage configuration. The solid fuel consists of 16 pallet loads arranged in a two-tier high, two-pallet load-wide and four-pallet load-long array. Each pallet load is a corrugated cardboard box sitting on a hardwood pallet. The simulations are performed using FireFOAM, with several key sub-models developed for water-based suppression, such as spray dispersion, surface film flow for cooling/wetting solid surfaces, gas-phase flame extinction/re-ignition, spray radiation attenuation, and soot emission reduction due to spray cooling. The simulation results are discussed in comparison with the test data.

An experimental program is conducted to investigate the parameters for extinguishing cooking oil fire by water-mist system with additive. The design parameters are dispatch flow rate and charge pressure. Also adding an additive to increase the ability of extinguishing cooking oil fire is validated in the test program. Two different agent percentage water-mist systems are investigated experimentally as well. Finally, the complete quantitative analysis is provided using data from experimental work.

Optical smoke detector suffers from significantly high false alarm rate caused by nuisance particles. A better knowledge of the optical properties of fire and non-fire aerosols will help to improve the performance of existing detectors. Scattering matrix analysis is a powerful methodology used in polarized light scattering. In this paper, we focused on the extraction of an indicator for discrimination between fire and non-fire aerosols. Numerical simulation of the angular distribution of single scattering matrix element by Lorenz–Mie theory and T-matrix method for smoldering fire smoke and flaming fire smoke, respectively, are presented for comparison with that of typical non-fire aerosols. The sensitivity of normalized scattering matrix element, F33/F11, to particle size distribution is investigated. The value of F33/F11 at 160° is proposed as an indicator for discrimination between typical fire and non-fire aerosols. Experimental measurement results for four aerosols, smoldering cotton fire smoke, flaming toluene fire smoke, dust and water droplets, demonstrated the effectiveness of this indicator.

The development of the logistics industry in Taiwan will continue to prosper nowadays and beyond. In order to save more human power while improving transportation effectiveness, the introduction of AS/RS to the storage warehouse has become a trend. It is wildly known that AS/RS warehouse has the characteristic of high risk on fire occurrence. Merely general specifications were presented in Taiwan’s code for the design of fire protection systems—the Standards for Installation of Fire Safety Systems Based on Use and Occupancy. Through literature review and fire scenario analyses in warehouse, we can realize that although the automatic sprinkler system activated confidently during a fire, the damage still happened. In this paper, sprinkler design situations of four typical AS/RS storage warehouses in Taiwan were investigated. Finally, compared to the literature review from each warehouse, the analysis of rack sprinkler configuration pros and cons were made. Meanwhile, some conclusions of sprinkler design were also provided for AHJ.

This study analyzes the types of duty associated with firefighter deaths, the age and rank of firefighters, and the cause of fatal injuries to firefighters who died 2007 through 2016. There were 193 Chinese firefighters died in line of duty in recent decade, excluding the firefighter deaths in 2015 Tianjing Port explosion. Twenty-one firefighters died for every million fire averagely and 51% fatalities occurred at the scene of emergency response. The firefighters died in 2007–2016 ranged in age from 18 to 51, with a median age of 26 years. The highest death rates were for firefighters between 18 and 25, accounting for about 60% of all. The first three largest shares of deaths were vehicle crash, stress or overexertion, and being caught or trapped, accounting for about 60% of all. The active service system seemed to be an economical institutional arrangement, but it caused the fire brigades always in a situation lacking of readiness. Efforts should be taken to perform genuine changes in the system, improve training, emergency scene operations, firefighter health and safety, and reduce the number of firefighter fatalities in the future.

Many super high-rise buildings are rapidly constructed in the urban area of Japan and Asia. The population and business activities of super high-rise office buildings are almost the same scale that of a city. If those businesses cannot continue after a big earthquake, huge economic loss and decrease of city function are expected. Therefore, the planning for business continuity after earthquake is strongly required. In addition, super high-rise buildings also have problems fire safety, and it becomes a large problem, especially after earthquake fire safety. To solve both problems, we proposed a comprehensive measure using intermediate refuge floors and its effect of vertical zoning. For business continuity, intermediate refuge floors are used as temporary refuge space for the occupants who cannot stay at their office area because of scattering of fixture, falling of ceilings and water leakage, and business facilities such as electricity and information facilities are divided by the intermediate refuge floors to limit the earthquake damage. As for fire safety, fire prevention equipment such as sprinklers, fire doors, fire shutters, and smoke exhaustion may be damaged by heavy shakiness. Therefore, we expect an intermediate refuge floor as a stable fire and smoke spread prevention measure. Through probabilistic analysis of 100 story model office building, we proposed effective installation measures that intermediate refuge floors are installed primary considering the fire and smoke spread control, and necessary business continuity performance is reinforced by earthquake damage management policy like reinforcing structure, steadily fixing office fixtures, and using flexible sprinkler pipes.

Helicopters are commonly used in search and rescue operations, and hoist operation accidents have occurred during helicopter search and rescue (HSAR) missions. The purposes of this study were to investigate whether the HSAR team to carry out the task of the hoist, may cause casualties accident risk factor. Through the Aviation Safety Council (ASC) database, we collected the statistical analysis of the major accidents of HSAR during 2000–2017, carried out case studies on the investigation report of the HSAR hoist operation casualties in the rear cabin, and semi-structured interviews were conducted with personnel involved in the implementation of the mission. Ensure the completeness through literature reviews and expert meeting discussions. A total of 12 HSAR accidents were identified during the study. Of these, 42% involved were related to hoist operation. The study indicates that there are four essential evaluation dimensions and some risk factors in HSAR missions.

A fire occurred at Bei-Men Hospital, a branch of Sinying General Hospital, on October 23, 2012. This fire caused 13 deaths and 59 injuries, and is regarded as the most severe hospital fire in history in Taiwan. This study adopted on-site investigation on October 30, 2012, one week after this fire, when the fire scene has not been changed much. The fire growth, smoke behavior, and the capacity of fire safety equipment in this fire were investigated particularly. After this survey, the failing of fire and smoke compartmentation on ceiling was found to be the primary cause for this severe fire. Some suggestions were made in the fire safety design for hospitals and ordinary buildings.

We investigated a fire accident which was caused by an ammonia coolant pipes’ removal operation. Fire investigation at the scene of the accident determined that the corridor was adequately ventilated, with the fastest wind speed at approx. 1.62 m/s near the corridor area of storage room R8, but the ventilation of the top area within storage room R8 was extremely inadequate, measuring a wind speed of nearly 0.0 m/s. The use of natural ventilation was incapable of removing the ammonia gas accumulated near the ceiling of the storage room, thus resulting in a fire and casualties among the personnel. Fire dynamics simulator (FDS) was used to simulate the corridor and ceiling wind speed as 1.7 and 0.0 m/s in the same scene. The results proved that FDS is proper tool to reconstruct the ammonia fire accident.

The application of performance-based fire safety engineering has enabled the conservation of a heritage building in New Zealand. McDougall House is a two-story heritage building which suffered extensive damages during the Canterbury earthquakes in 2010 and 2011. The scope of repair work carried out included the preservation and restoration of the building external façade, the restoration of the ornamental plasterwork ceiling within the Ballroom, the reconstruction of all damaged internal wall linings, the adaptation of the fireplace, and the reconstruction of the damaged chimney. The fire safety design adopted is the Verification Method C/VM2 with As Nearly As is Reasonably Practicable consideration for the heritage fabrics of the building. The combination of quantitative and qualitative analyses, including smoke and egress modelling, assessment of allowable unprotected areas in external wall for horizontal fire spread, and benefit versus sacrifice analysis on the heritage fabrics have demonstrated compliance with the ten design scenarios of C/VM2, retaining the majority of the cultural heritage values, and also improving the level of fire safety of the building.

The objective of this research was to investigate performance-based fire safety design in satisfying the tenability criteria of high-rise buildings with an occupancy load of greater than 1000 people per stairwell. This was completed through a sensitivity analysis of a 20-story high-rise building model using the Fire Dynamics Simulator for modeling a range of fire scenario. A total of 16 simulations were analyzed, with varying building parameters such as room geometry, sprinkler type, detection devices, and egress door configuration. The building was designed to comply with the New Zealand Verification Method (C/VM2). The acceptance criteria for visibility, toxicity, and thermal effects, were taken from the New Zealand Building Code (NZBC). The results for all simulations showed that the visibility requirements in the stairwell were the controlling tenability criteria when compared to the carbon monoxide and thermal effects. The results demonstrate the need for smoke detectors in conjunction with sprinklers in high-rise buildings.

As buildings get taller, the issue of safe egress from these buildings becomes an increasing concern. The provision of dedicated refuge floors is a recent design measure that has arisen in an attempt to address the concern of increased hazards associated with egress from tall buildings. Although there have been studies on the perceived benefits in the provisions of refuge floors, little has been studied in depth on its actual performance in terms of achieving the expected safety for egress from tall buildings. This paper attempts to provide a deeper insight into the impact of refuge floor provisions and to assess the extent of the benefits toward achieving a safer outcome for occupants during a fire emergency egress from tall buildings. The general conclusion is that dedicated refuge floors may not necessarily deliver a safer or cost-effective solution.

In this study, the water spray system of sidewall type in the tunnel fire is simulated by Fire Dynamics Simulation (FDS) where the effect of critical velocity with water spray systems in tunnel fires, the critical velocity variations with various heat release rates, droplet sizes, and water flow rates in tunnel fires have also been investigated. In the tunnel fire model, the heat release rates are from 1 to 10 MW, the performances of the water spray system adopt the same regulation of Nohmi Bosai Ltd. Japan. A metal sheet, with 3 m in length and 2 m in width, is set in 3 m above the fire source. The results of various critical velocities obtained from this tunnel model without water spray system are good agreement with other references. The result shows that the critical velocity is lower after using the water spray system. In the same water flow rate, when the droplet size is smaller, critical velocity is lower simultaneously. In the same droplet size, when the value of water density is bigger, the critical velocity is consequently lower. This study also investigates the vertical temperature distributions in tunnels from various parameters of water spray systems.

The Qiongzhou Channel tunnel, which is under construction in China, is taken as an example to study the evacuation of a train in a tunnel. Fire Dynamics Simulator (FDS) and Pathfinder software are utilized to simulate the fire spreading and personnel evacuation. When a fire broke out in the tunnel, the process can be divided into three stages according to the development of fire, which are carriage fire period, fire spread period, and tunnel fire period. The safety of people evacuation in different stages was studied. It has been found that when a fire occurs at the carriage center, people can evacuate to the adjacent carriages safely. In the event of a fire happens at the carriage end, high temperature and smoke would threaten the safety of passengers. If the fire train could drive to the emergency rescue station, it has been proved 200 s ahead to protect passengers than driving outside, and people can evacuate to safety area within the available safety evacuation time. The results show that it is necessary to have an emergency rescue station in the extra-long channel tunnel, and cooling equipment and fire-extinguishing installations should be equipped in carriages to ensure passengers safety.

In the process of sealing tactics against tunnel fire (STATF), sealing rate defined as sealing ratio per unit time, impacts upon sealing firefighting effect via influencing the air flowing, smoke exhaust, etc. A 1/9 small-scale tunnel model was established to study the effects of sealing rate on tunnel fires in this paper. Taken fire size and sealing rate into account, the mass loss rate (MLR), temperature characteristics, and fire overflow were compared and studied. The results show that the MLR starts to drop earlier with the increase of sealing rate. Furthermore, a new parameter, sealing efficiency (denoted by λ), is introduced related to the moment of ceiling temperature in tunnel center turning to drop and the initial sealing time. It is found that the sealing efficiency is improved with the increase of sealing rate. Notably, sealing efficiency minimizes to minus when sealing rate reaches its minimum, indicating that it would have a negative feedback effect on fire extinguishment when sealing rate reduces to a certain degree. In addition, with the decrease of sealing rate, the maximum radiation heat near the tunnel entrance is higher and the existence duration of high-temperature smoke gets longer, which might pose a greater threat to firefighters.

A road tunnel is an enclosed space where backlayering of smoke produced by a fire can extend its damage beyond the part exposed to the fire. To realize a worry-free and safe infrastructure, emergency facilities in tunnels must be improved. Since it is difficult to uniformly apply improvement projects to all tunnels in the face of limited project budgets, it is necessary to prioritize projects to perform improvements systematically. As a method of efficiently conducting these projects, a statistical risk calculation method based on fire accident statistics obtained by defining individual tunnel fire accident risk as “(probability of occurrence of fire in a tunnel) × (loss),” has been proposed. This permits ranking the risk, allowing to set risk improvement project priorities. But to clarify risk improvement effects, medium to long-term observations are necessary. For human loss, which is the loss with the greatest impact on risk, a method of calculating change of potential risk by fire simulation and evacuation simulation has been proposed. But in order to calculate the potential risk of many tunnels, vast computing resources and long periods of time are needed. Therefore, another method was studied, using the results from a model tunnel, and performing evaluations linking fire simulations with evacuation simulations under a variety of conditions as a database. This paper introduces a potential risk calculation method suitable for individual tunnels based on the results of multiple regression analysis performed using these data.

We propose the use of network flow analysis for designing and optimizing the smoke control in urban traffic link tunnels (UTLT) with multiple branches. Up-to-date, there have been no specified codes and standards for the application of conventional smoke control measures, such as jet-fan induced longitudinal ventilation and centralized smoke extraction using axial fans, in such tunnels. The use of network flow analysis could avoid the huge computational cost in large and complex tunnels. A self-developed network code incorporated with basic conservation equations was employed in a practical UTLT. The simplification algorithms for calculating the heat transfer rate at the tunnel envelopes and the gas species generation around the fire source were newly presented in this paper. The network analysis results are compared against a three-dimensional numerical simulation, and good agreements were obtained between them. Then, a hybrid mode including a combination of longitudinal ventilation and centralized extraction was simulated using the network code. The benefits and applicability were discussed.

This research is using methods model experiments and numerical simulation in tunnel respectively to discuss what influence that stationary vehicles located in upwind fire source would have on backlayering length Lb of thermal fume. In this experiment, the same scale of the fire source was adapted, and the variables are the obstacles height of upwind fire source. There are two kinds of obstacles: lower obstacles and higher ones; the configuration is divided into two kinds: no stationary vehicles (M0) and both sides of stationary vehicles (M2). This experiment is using 1/5 model of the tunnel, and the model material Biot number and Fourier number is close to the full-scale tunnel. In terms of numerical simulation, a full scale model was built by original code which is self-developed and then calculated the fire source scale and time range of quasi-steady used in numerical simulation with dimensionless formula and Froude scaling methods respectively. Comparing the relation between dimensionless backlayering length Lb/H and Q*1/3/Fr with curve fitting equation proposed by Kunikane (11th International Symposium on AVVT, Luzern, Switzerland, pp. 87–101, 2003 [1]), it shows that under the same Froude number circumstance, the Lb with obstacles is shorter than that without obstacles. Also, model experiments and numerical simulation both show similar result. Thus the original code used for numerical simulation in this study is suitable for studying the effect of stationary vehicles on Lb. After analyzing the effect of stationary vehicles on the longitudinal velocity, it is found that in the case of M2, the longitudinal velocity on the upper part of the tunnel is bigger than that of M0. Therefore, the Lb in M2 is shorter than that in M0. Because, in the case of M2, higher obstacles cause the wind speed of the upper part of the tunnel to become faster, which in turn causes the Lb to become shorter and the slope of the fitting curve to become smaller.

In recent years, the application of point-extraction ventilation systems in road tunnels has attracted worldwide attention. Considering the experience of tunnel fire disasters, Taiwan Eastern Highway Project with eight tunnels about to open to traffic has also adopted this type of ventilation system. However, the smoke layers are possibly diffused by the exhaust flow in the vicinity of the extraction vent during emergency ventilation when a tunnel fire and then the smoke could deteriorate the evacuation environment. This study used Froude-scaling methods and dimensionless models to simulate experimental conditions with CFD software (our original code). These simulations of smoke distribution were compared with results from experiments with a 1:5 scale-model tunnel equipped with a point-extraction ventilation system. The predictions of smoke propagation derived by the original code are in good agreement with the scale-model experiment results. Furthermore, through conformed the CFD cord accuracy, we could have the prediction and understand the smoke behaviour affected by this type of ventilation system, in order to assess the influence on the safety of evacuation environment in full-scale tunnel fire accident.

To address fire safety of cable compartment in urban utility tunnel, provision of fire separation is necessary, and identifying a fire separation distance that is both safe and practical is thus of great importance. This paper studies the cable compartment fire occurring and development pattern, fire smothering, post-fire ventilation, and smoke exhausting under different fire separation distances by CFD numerical simulation. This paper proposes a general process for fire smothering in cable compartment of urban utility tunnel and comes up with a series of judging criteria for the best fire door opening time. The research discovers that under different fire separation distances, there is not big difference in maximum heat release rate (HRR) as well as the maximum temperature and smoke layer settling rate in the utility tunnel. After fire door is opened, the smoke exhaust time with an 800 m fire separation distance is obviously higher than any other fire separation distance. We believe that the present mainstream 200 m fire separation distance can be properly increased no matter from the perspective of fire spreading control or post-fire ventilation, for example, no excess of 500 m. The research results of this paper can provide theoretical basis for fire safety design and management of urban utility tunnels.

Emergency ventilation systems are commonly used for smoke control during tunnel fires. Numerical results show that the fire and smoke would be confined effectively by the water mist screen and transverse ventilation system (WMSTV system) system, and the environment inside the confined zone would be suitable for occupants’ evacuation and fire fighting. In this paper, the smoke control parameters of WMSTV system are proposed. The visibility distributions and smoke extraction efficiency are analyzed by FDS simulation. The results show that the minimum spacing distance between smoke vents should not be less than 40 m, while the maximum spacing distance should not exceed 60 m for 30 MW of fire. The spacing distance between the screen and vent is suggested to fall in 30–45 m. Two vents are recommended in the control zone with the screen spacing of 120 and 150 m. Four vents are recommended in the control zone with the screen spacing of 180 m.

Combustion efficiency in tunnel fires was measured using a 1:20 scale model tunnel with a 0.25-m height, H, while varying the length of the model tunnel, L, as the experimental parameter. A series of fire experiments was conducted to confirm whether combustion efficiency was affected by the tunnel length, L. A dimensionless tunnel length defined as L* = L/H was selected as L* = 8, 16, 24, 32, 40, and 48, corresponding 40–240 m in full scale. The results showed that combustion efficiency was not affected by the dimensionless tunnel length ranging from L* = 8–32, and its average value was 90%. However, when the dimensionless tunnel length was L* = 40 or more, part of the smoke flowing under the ceiling of the model tunnel descended to the floor, and the smoke descent phenomenon dramatically changed the flow dynamics of the smoke. As a result, the flame on the gas burner became unstable, and ultimately the ghosting flame phenomenon was observed close to the fire source. We qualitatively discussed the cause of the ghosting flame phenomenon, in addition to combustion efficiency.

In this study, the authors numerically simulated heavy goods vehicle (HGV) fire scenarios in order to investigate the tenable conditions of a two-way traffic road tunnel with point-extraction ventilation system consisting of water spray system. A computational fluid dynamics (CFD) model was used to simulate the interaction between the point-extraction ventilation and the water spray system. A total of four cases were carried out in a 600 m tunnel model. Distributions of smoke, temperature, visibility, and CO concentration profiles in tunnels axial-sections for the considered model and point-extraction ventilation system were provided. Results show that the characteristics of tenable conditions for the tunnel fires having water spray are distinctive from those of the tunnel without water spray and ventilation. Tunnel with the point-extraction ventilation and water spray system can provide the relative safety region for occupants at the outside of the water spray zone once HGV fires occur.