Fire Hazard Assessment Research Articles

Оценка пожаро- и взрывоопасности систем местных отсосов и способы их очистки

Оценка пожаро- и взрывоопасности систем местных отсосов и способы их очистки

Effect of flow rates of gases flowing through a coal bed during coal heating and cooling on concentrations of gases emitted and fire hazard assessment

The flow velocity of gases in gobs directly influences the kinetics and intensity of gaseous components release during heating and cooling of coal. The assessment of fire hazard is performed on the basis of concentrations of particular gases in a mine air. These concentrations differ in coal heating and cooling phase which was proven in the study. This paper presented the results of the experimental study on temperature distribution in a simulated coal bed in heating (50–250 °C) and cooling (250–35 °C) phases as well as its correlation to variations in concentration of gases released in these phases and flow rates of gases flowing through the coal bed. The research was performed on twenty-two samples of bituminous coals acquired from various coal beds of Polish coal mines. Considerable differences were observed between heating and cooling phases in terms of the concentrations of gases taken into account in calculations of self-combustion index. In the heating phase temperature increase resulted in the decrease of concentrations ratios of ethane, ethylene, propane, propylene and acetylene, while in the cooling phase these ratios increased systemically. The effect of air (in heating phase) and nitrogen (in cooling phase) flow rate on the self-ignition index CO/CO2 was also determined.

Experimental Assessment of Explosion and Fire Hazards of Lithium Current Sources

In this Letter, we propose a method for quantitative assessment of the explosion and fire hazards of lithium–thionyl chloride elements, describe an experimental setup, and present the results of experiments with lithium–thionyl chloride elements of D and DD sizes.

Experimental and numerical thermo-mechanical analysis of the influence of thermoplastic slabs installation on the assessment of their fire hazard

This work aims at determining the influence of orientation and dimensions of structural samples on the measurement of their burning properties and therefore on the assessment of fire hazard. Poly (methylmethacrylate) (PMMA) slabs are tested thanks to a new experimental setup specially designed to study the combustion of large samples exposed to medium to high radiative heat fluxes. The experimental results evidence a relation between the heat release rate (HRR) and structural phenomena such as mechanical instability, slump, collapse and material flow. The understanding of the dimensions-behavior relationship is completed by finite element simulations of the conducted experiments. The thermo-mechanical simulations consist in the sequence of a transient thermal computation up to a given heating time followed by an eigen buckling calculation, all encapsulated in a parametric study of that heating time. The evolution of the buckling critical load factor as a function of heating time allows predicting for samples of different sizes the time needed to buckle. These simulations corroborate the experimental results, namely that buckling occurs sooner for thin or large samples, which elucidates the discrepancies between the fire response assessed in vertical and horizontal sample orientations.

Lower Explosion Limits Measurements and Prediction for Binary Liquid Mixtures

The lower explosion limit (LEL) is an important physicochemical parameter for characterizing the flammable and explosive hazard potential of chemicals. In this study, the LEL values of 21 groups of binary liquid mixtures with different compositions and ratios were tested, and the change law of LEL with compositions and ratios were revealed. Then four different physicochemical parameters were employed as the input parameters for the LEL prediction of mixtures. Both the multiple linear regression (MLR) and multiple nonlinear regression (MNR) methods were employed to model the possible quantitative relationships between these parameters and the LEL of binary mixtures. The resulted models showed satisfactory prediction ability, with the average absolute error being 0.188% for the MLR model and 0.196% for the MNR model, respectively. Model validations were also performed to check the stability and predictivity of the presented models, and the results showed that both models were valid and predictive requiring only some common physicochemical parameters of the pure components. This study can provide a simple, yet accurate way for engineering to predict the LELs of binary liquid mixtures as applied in the assessment of fire and explosion hazards and the development of inherently safer designs for chemical processes.

Forest fire induced Natech risk assessment: A survey of geospatial technologies

Forest fires threaten a large part of the world's forests, communities, and industrial plants, triggering technological accidents (Natechs). Forest fire modelling with respect to contributing spatial parameters is one of the well-known ways not only to predict the fire occurrence in forests, but also to assess the risk of forest-fire-induced Natechs. This study is a review of methods based on geospatial information system (GIS) for modelling forest fires and their potential Natechs that have been implemented all over the world. The present study conducts a systematic literature review of the methods used for forest fire susceptibility, hazard, and risk assessment, while dividing them into four general categories: (a) statistical and data-driven models; (b) machine learning models; (c) multi-criteria decision-making models, and (d) ensemble models. In addition, some forest fire detection techniques using satellite imagery are reviewed. A comparison is also conducted to highlight the research gaps and required future research. The results of the present research assist decision makers to select the most appropriate techniques according to specific forest conditions. Results show that data-driven approaches are the most frequently applied methods while ensemble approaches are more accurate.

Review of the fire risk, hazard, and thermomechanical response of bridges in fire

Resilient design requires information about a structure’s response to a variety of exposures such that systems can be implemented to prevent unacceptable losses. For the case of critical infrastructure like bridges, losses associated with structural damage and traffic closures from fire events can be substantial. Despite this, there are no specific code requirements for bridge fire safety in different national jurisdictions, particularly in North America and Europe, and only minimal guidance available for establishing the fire resistance requirements of bridges. Research into the fire safety of bridges is ongoing but knowledge gaps persist that limit practitioners’ ability to conduct performance-based fire designs using the latest state of existing research. This paper provides a first-stage state of the art review of bridge fire research conducted to date in effort to summarize key findings and make available the most relevant information for researcher and practitioner use. The key research themes considered as subdivisions are fire hazard and risk assessment, bridge fire scenario modelling, and the structural response of steel and composite steel-concrete, cable-supported, concrete, and fiber reinforced polymer bridges to fire. The authors conclude the study with identified knowledge gaps and priority research areas.

Fire and Explosion Risk Assessment for the Republic of Croatia

Through a spatial and statistical analysis, the paper aims to assess vulnerability based on the service capabilities of public fire brigades in the Republic of Croatia. An assessment of fire hazard impacts was developed based on historical fire data over a twenty-year period for the counties and City of Zagreb, an assessment of exposure based on critical infrastructure data for the counties and City of Zagreb, and an assessment of resilience based on the coverage zones of fire brigades within the standard intervention time (15 min) for the counties and City of Zagreb. The results of the research have various potential applications and can be used as a basis for the future planning and development of the fire protection system to serve and protect people, material and cultural goods.

Assessment of Fire Hazard on the Readymade Garment Industry in Chittagong City, Bangladesh

The Readymade Garments (RMG) industries are in Bangladesh is the largest contributor to the national export earnings and second largest in GDP of the country. Starting from the late Seventies as minor as well as non-traditional sector with a negligible of exporting, the RMG sector has dramatically grown up a geometric progression over the few decades. Although the country has a glorious history of textile, cloths and clothing’s from the ancient period of time. At present, about 75% of the total exports of the country having from this sector and one of the principle key points of employment. Over the preceding decade, fire and fire hazard is the continual problem in the country’s readymade garments industries. Only in 2012 about 169 people died and huge people are injured because of fire hazards in RMGs. Considering this as a crucial problem, the study was carried out a geo-spatial analysis on Chittagong Export Processing Zone (CEPZ) and Baizid Industrial hub of Chittagong city, Bangladesh. The study was mainly done by primary field survey while secondary sources were also used in comparing and basement of analysis. There are two types of parameters (Hard and Soft Parameters) generally used to assess the fire hazard of readymade garments. The research has been done by adopting the soft parameter, as exit door locked, emergency exit in the factory, fire extinguisher etc. The Fire Risk Index has been developed on the basis of 19 soft parameters. In Chittagong EPZ area 25 garments factories have been surveyed instantly to observe the current status of fire risk for the lack of 19 parameters. Results show that in CEPZ area for 19 parameters the mean safety is 90.45% or 9.55% deviation from the standard. On the contrary, the average condition of 19 parameters is 80.29% fluctuation from the benchmark in the Baizid Industrial area though it is considered as good condition but nearest to the average. Electric short circuit is the prime cause of fire in CEPZ area and also in Baizid industrial hub. At the eleventh hour, it is found from the study that about 80% garments in Baizid Industrial area under in good condition which is (10-20) % deviation from ideal case. On the other hand in CEPZ area about 80% garments are fallen excellent condition, it is only 8% seen in Baizid area. The study also reveals that there is no garments in both area which is in poor or average condition or vulnerable to fire hazards but in Baizid it is about 20% garments are fallen average condition or nearly vulnerable. Before conducting the study, it is seemed that it will be found the garments will be more vulnerable to fire hazards but at the end of the day it is proved as erroneous, for the recurrence of fire hazards in the last few years they have raised the magnitude of fire safety in almost every cases and now the garments are more secured in case of fire hazards.

Risk-based automated system for prediction of fire safety in railway facilities

Aim.The development of the Russian railway industry is associated with the growing number of operated buildings, rolling stock, more complex business processes of infrastructure maintenance and client service. In this context, JSC Russian Railways (JSC RZD) needs to manage the fire safety of more than ten thousand units of traction rolling stock and hundreds of buildings, where potential fires may cause harm to passengers or interruption of service. Fire safety management of both fixed and mobile railway facilities is performed at all lifecycle stages from design to disposal. Implementing the processes of fire safety diagnostics and prediction requires the development of a man-machine system whose core would be an automated fire risk control system (ACS) that allows – basedon the fire risk prediction – makingdecisions regarding the requirement for the repairs, replacement or maintenance of railway facilities and fire safety systems. Methods.The methods of the automatic control theory, expert assessment were used. The study aimed to develop an algorithm of automated auditing of railway facilities fire safety. Results.It is established that the majority fire safety control systems use gas concentration sensors to detect symptoms of hazard before flame development. This approach is hardly effective in terms of fire safety of railway facilities. For railway facilities whose actual state has an effect on the probability of fire a fire audit algorithm was developed that is based on the existing service and repair system, as well as statistical data on the states of railway facilities that precede fire. In order to enable systematic risk management measures in a large number of railway facilities, the paper proposes the structure of an automated fire risks management system that includes a fire safety management center and a mobile hardware and software system for fire safety auditing. Conclusions. It shows the importance of developing a proactive fire safety management system based on fire risk assessment. It was identified that information on the states preceding fires in railway facilities can be obtained from both the existing automated failure reporting and risk assessment systems and the diagnostic results of the actual state of objects as part of scheduled preventive maintenance. A method of automated assessment of fire hazard is proposed for systematic management of fire risks in many railway facilities.

Scale effect of mass loss rates for pool fires in an open environment and in tunnels with wind

This paper investigates the influence of wind on mass loss rate per unit area (MLRPUA) of fuel-controlled pool fires both in an open environment and inside tunnels and the scale effect of pool fires is also investigated. Large pool fires with a diameter D greater than 1 m (D > 1 m) are of key concern but small pool fires (D < 1 m) are also considered for comparison. This is done by analyzing large amounts of experimental data from the literature. Results show that for small pool fires (D < 1 m) in an open environment, increasing wind speed tends to increase the MLRPUA, especially for pools with D < 0.2 m, where the MLRPUA could increase significantly with the increase of wind speed. But when small pool fires occur in tunnels, the results are more complex. When the ratio of effective tunnel height to pool diameter is less than 3, increasing wind speed tends to decrease the MLRPUA. When this ratio is greater than 3, the influence of wind on MLRPUA of pool fires in tunnels is similar to that in an open environment. The influence of wind on the MLRPUA decreases for larger pool diameters, no matter whether the pool fire occurs in an open environment or in a tunnel. For large pools with D > 1 m, the MLRPUA is not affected significantly by increasing wind speed and most likely varies within 30% for a wide range of wind speeds based on the test data collected. This influence is far less than the values concluded by previous studies based on small pool fire experiments. The outcome of this study contributes to improving the understanding of burning characteristics of pool fires under windy conditions, especially large pool fires, which are much more meaningful than small pool fires from the perspectives of fire protection engineering and fire hazard assessment.

Экспериментальная оценка взрыво- и пожароопасности литиевых источников тока

The method of quantitative assessment of explosion and fire hazard of lithium - thionyl chloride elements is proposed, the experimental setup is described and the results of experiments with lithium-thionyl chloride elements of sizes D and DD are presented.

Fire Hazard Assessment of New Automotive Battery Materials Using SDS Information

Fire Hazard Assessment of New Automotive Battery Materials Using SDS Information

Selective adsorption of ethane, ethylene, propane, and propylene in flammable gas mixtures on different coal samples and implications for fire hazard assessments

Sorption studies of gaseous mixtures of ethane, ethylene, propane, and propylene allowed us to obtain a better understanding of flammable gas behavior during flow through a coal seam. The dynamic sorption method was used to characterize the behavior of the multi-component gas mixtures. In these experiments, a gas mixture was released during a simulated heating process for coal and was then flown through a fixed bed of coal with particle sizes of 0.5–0.7 mm. The composition of gaseous effluent flow at the inlet and outlet of the sorption column was analyzed by gas chromatography (GC). The mixture composition influenced the amounts of sorbed gas, and variations occurred as a result of differences in the coal permeability. Both the high content of ethane in the mixture and its mechanism of sorption resulted in faster retention times for this gas. Propylene, which was characterized by low concentrations, was sorbed in the largest amounts and had the least steep adsorption curves compared to the other gases. The coal adsorbent with the largest surface area as determined by micropores and mesopores sorbed the largest amount of gases. These findings suggest that sorption measurements in which only a single gas is considered are not reflective of the real conditions in coal mines. Therefore, studies on flammable gas mixtures under dynamic states have great significance in terms of fire hazard assessments.

Experimental Study on Fire Behaviors of Kerosene/Additive Blends

The widely used fuels in practical are blended fuel whose combustion characteristics is more complex than those of the single-component fuel in real fire scenarios. The fire behaviors of aviation kerosene/diethylene glycol dimethyl ether (DGM) blends (R-D) and aviation kerosene/ethanol (R-E) blends were studied using a cone calorimeter. The parameters of pool fires, including the ignition time, burning rate, fuel temperature, heat release rate and combustion yield, were investigated. Janssens’ method was adopted to analyze the ignition times of the two blends. Two types of representative burning processes for blended fuel pool fires were identified. For R-D blends, the burning process is similar to that for typical pure fuels. The process for R-E blends, however, is novel, having two obvious burning processes due to the appearance of an intermediate decay stage. The fuel exhaust mass fraction (approximately 15%) was found to be almost constant throughout the intermediate decay stage. The fuel temperature during the experiment indicated that the liquid surface boiling temperature of R-D blends ranges from 162°C to 200°C depending upon the composition of these blends. For R-E blends, the initial boiling temperature is affected by the ethanol ratio, while the boiling temperature in the second process is equal to the boiling temperature of pure RP-3 kerosene. When the ethanol ratio is lower than 40%, the initial boiling temperature of R-E blends is approximately 120°C; when the ethanol ratio is higher than 40%, the boiling temperature is equal to the boiling point of ethanol. A method for calculating the burning rate of each component in the burning processes of the two blends is put forward, with the results agreeing well with the interpretation of the two burning processes. The ratio of the combustion yield CO2/CO and the carbon conversion ratio increase with the oxygenated fuel ratio, indicating that the combustion is more complete when oxygenated fuel is added. These results will be useful for fire hazard assessment and firefighting in terms of fuel storage and transportation.

7-2-1 PVシステムにおける火災事故を対象としたリスク評価

7-2-1 PVシステムにおける火災事故を対象としたリスク評価

Vertical forest structure analysis for wildfire prevention: Comparing airborne laser scanning data and stereoscopic hemispherical images

Vertical fuel structure is critical for fire hazard assessment in forest ecosystems. Forest stands with ladder fuels are more prone to crown fires because of canopy fuel continuity. However, characterization of ladder fuels is difficult in the field and few studies have developed explicit measurement procedures to account for these hazardous fuel situations. This study compares vertical profiles derived from airborne laser scanning (ALS) data and stereoscopic hemispherical images obtained in Pinus sylvestris stands in central Spain to test their ability to detect the presence or absence of vertical fuel continuity (VFC). Vertical fuel profiles based on canopy cover fraction estimations at different height strata were assessed at plot level and compared with field observations. The quadratic form distance (QFD) was the metric used to quantify the similarity between histogram distributions defined by the vertical profiles from different datasets. Logistic regression analysis was tested to discriminate areas with and without VFC from ALS data at two threshold levels (15% and 30%). The vertical fuel profiles of canopy cover showed a different level of correspondence depending on the relative amount of ladder fuels. Significant logistic models were found (p < 0.0001, c-index>090) for different combination of ALS metrics, with low percentiles (up to P30), canopy relief ratio (CRR) and the percentage of returns normalized by height strata (PRN) up to 8 m as the best predictors to identify the presence of VFC. Results indicated that both datasets were useful in retrieving variability of forest fuel distribution, but further methodological improvements (e.g. understory segmentation in stereoscopic images, new algorithms to better account for occlusions, or ground calibration for laser attenuation in ALS) are needed to increase accuracy in highly continuous areas.

Fire Hazard Assessment During Construction of A Mixed-Use Development Project In Kuala Lumpur

Construction by nature is inherently dangerous, with a high degree of hazard and risk. Serious fire has occurred in building under construction, which will not delay their completion dates and loss of life, but also result in serious monetary losses. The objectives of this paper are to investigate the causes of fire hazard during the construction phase; assess the risk level arising from the fire hazard during the construction phase; and tpropose safety control measures of fire hazard during the construction phase. Primary data is obtained from the respondents of a mixed use development project in Kuala Lumpur via questionnaire surveys. The data is analysed via Statistical Package for the Social Science (SPSS) and Hazard Identification, Risk Assessment and Risk Control (HIRARC). The findings show that the most important causes of fire hazard of a mixed-use development project are related to workers site activities. Meanwhile, HIRARC identifies that fire hazard from hot works and use electrical tools are the most important risks. Lastly, safety control measures were proposed to control the identified fire hazard by improving the operating procedure of hot works and use of electrical tools as well as implementing good housekeeping practices and inspection at the workplace.

A simple model for shrub-strata-fuel dynamics in Quercus coccifera L. communities

We model the dynamics of fuel characteristics in shrub strata dominated by Quercus coccifera L. with data gathered in available literature. The model expresses the variability of this important fire-prone fuel type thanks to yield classes, and it can be used to investigate management scenarios. The approach could easily be applied to other shrub communities. Characterizing fuel is a basic requirement for fire hazard assessment. Quercus coccifera L. is present in several Mediterranean fire-prone communities, and its fuel characteristics have been studied over various Mediterranean countries, but no general model describes its dynamics. Herein, we present such a general model, initially developed for operational purposes at the French Forest Service. We review available literature and fit statistical relationships to predict the dynamics of fuel height and biomass, by size categories of fine fuel elements. The model estimates fuel characteristics from shrub-strata age, overstorey cover, and yield class with a reasonable degree of accuracy considering the heterogeneity of the datasets. It shows that bulk density is highly sensitive to overstorey, and in a lesser extent to strata age, which could lead to significant bias when assessing fuel properties from general allometries. The model is integrated in the FuelManager software, which is devoted to fuel modeling for physics-based-fire-behavior models. This simple approach enables to provide a fuel model for the Quercus coccifera L. shrub strata in the Mediterranean basin. It is more general than the existing relationships available for local data. This approach could be generalized to other fire-prone communities.

FORECASTING OF FIRE DANGER BY WEATHER CONDITIONS IN FORESTS OF THE GREEN BELT OF KHARKIV CITY

The tendency of the fire emergence in the forests of Kharkiv city green belt was studied in the case of the forests located in Zhovtneve Forest Enterprise for the period of 2005–2017. The numbers of fire occurrences have been analysed and compared with the current system of assessing the fire hazard class in Ukraine. By the weather conditions the effectiveness of the system was assessed for the studying territory. The features of the emergence of fires in different months of the fire hazard period were investigated and the difference in numbers of forest fire occurrences was determined in separate seasons and decades of months. The number of fire incidents on an average per day has been analyzed for different classes of fire danger in the spring, summer and autumn seasons. According to the proportion of emerging fires and by the method developed by P. Kurbatskiy, modifications were made to the scale of assessment of fire hazard by weather conditions taking into account the season of the year.