Fire Investigation Research Articles

The role of numerical modeling in scientific fire investigation

Fire risk is perhaps the most common risk in the category of special emergencies, being a phenomenon that affects important areas of economic and social life, such as buildings, industrial facilities, public spaces, forests, crops, or transportation. Scientific investigation of fires is constituted as a set of organized actions, of technical nature, undertaken to determine the causes that led to the occurrence of fires, the source of ignition, and the circumstances that favored the event. Numerical fire modeling is a widely recognized and accepted tool for analysis in fire research. The results of the investigation carried out on-site are compared with the results of fire evolution obtained by computer simulation, using numerical models based on known input data, to verify different hypotheses regarding the cause of the fire. The advantages over experimental methods are expressed by low costs and substantial time savings. Moreover, several simulations can be run simultaneously, for different scenarios of the event or the analysis of different consequences. The paper presents the main advantages that numerical modeling by FDS methods brings in the technical-scientific expertise of fire, with implications in the data analysis, development, and testing of hypotheses, respectively in the selection process of the final hypothesis. words.

Numerical studies on an accidental flashfire at a water fun park by FLACS software

A severe accidental fire with ?explosion? resulting from spraying colored corn flour powder occurred at a water fun park in Taiwan. The possible fire scenarios were studied in this paper using flame acceleration simulator (FLACS). Environmental conditions including wind action and solid boundary conditions were deduced based on government fire investigation and video records, and were used as the input parameters in simulation. Simulation results indicate that upon ignition of the sprayed powder, the maximum overpressure in the open space was only 0.03 bar gauge, with a dust flash fire generated without having an explosion. These environmental conditions or parameters and the simulation results together would give a fire scene that agrees with the accident observed, indicating that appropriate environmental parameters had been identified. Therefore, CFD simulation with carefully selected parameters can be used to reproduce explosion scenarios and to identify key factors in supporting accident investigations.

A Study to Verify the Practicality of Introducing an Arson Dog (K-9) Unit in Field Investigations

Combustion improvers are often found in acts of arson. Until recently, in fire investigations in Korea, these substances have been identified only by the olfactory sense of the fire inspectors or conventional gas detectors. These methods are neither efficient nor feasible in damaged buildings or large areas. Research on the canine sense of smell has shown that a dog can distinguish the remains of combusted hydrocarbon compounds, even in a large, open area. Field tests confirmed that arson dogs can find combustion improvers at fire sites in about five to 77 s. Therefore, this study verified the practicality of introducing arson dog units in field investigations of fire sites to identify combustion improvers sprayed for committing arson.

Recognition of gasoline in fire debris using machine learning: Part I, application of random forest, gradient boosting, support vector machine, and naïve bayes

The detection and identification of ignitable liquid (IL) residues in fire debris are two very challenging tasks in a fire investigation. To this day, the recognition of IL in fire debris includes the chemical analysis of the fire debris composition, followed by the examination and interpretation of the analysis result by a trained forensic examiner. Throughout the last decade, chemometrics and artificial intelligence have become increasingly important. In the present study, machine learning algorithms capable of recognizing gasoline residues in fire debris based on GC-MS data have been developed. Four methods, including random forest, gradient boosting, support vector machine, and naïve bayes are applied and used to classify fire debris samples into the two categories “with gasoline” or “without gasoline”. A fifth method (logistic regression) did not converge due to well separated classes. A database comprising 360 measurements, including fire debris samples of real cases as well as fire debris samples spiked with known amounts of weathered gasoline (up to 99.6%), was available to train the machine learning algorithms (using 85% of the data) and to subsequently test the performance of the methods when classifying unknown samples (using 15% of the data). In general, the methods perform very well, as three of it succeeded to classify all test samples correctly without any false positive or false negative allocations. One (naïve bayes) was not trained enough to classify other (non-gasoline) IL correctly as “no gasoline”. Furthermore, the random forest method reveals which chemical compounds are most relevant for the algorithm to classify the samples. In general, the presented approach is highly promising and could easily be extended or adapted to other types of IL. Similar to the neural network presented in the accompanying paper, such methods have the potential to serve as a fast screening technique for fire debris samples, thus supporting the forensic examiner by providing an additional independent opinion. Nonetheless, the definite identification of IL residues in fire debris always has to be accomplished by a forensic examiner.

Airborne contamination during post-fire investigations: Hot, warm and cold scenes

Fire investigators may be occupationally exposed to many of the same compounds as the more widely studied fire suppression members of the fire service but are often tasked with working in a given exposure for longer periods ranging from hours to multiple days and may do so with limited personal protective equipment. In this study, we characterize the area air concentrations of contaminants during post-fire investigation of controlled residential fires with furnishings common to current bedroom, kitchen and living room fires in the United States. Area air sampling was conducted during different investigation phases including when investigations might be conducted immediately after fire suppression and extended out to 5 days after the fire. Airborne particulate over a wide range of dimensions, including sub-micron particles, were elevated to potentially unhealthy levels (based on air quality index) when averaged over a 60 min investigation period shortly after fire suppression with median PM2.5 levels over 100 µg/m3 (range 16–498 µg/m3) and median peak transient concentrations of 1,090 µg/m3 (range 200–23,700 µg/m3) during drywall removal or shoveling activities. Additionally, airborne aldehyde concentrations were elevated compared to volatile organic compounds with peak values of formaldehyde exceeding NIOSH ceiling limits during the earliest investigation periods (median 356 µg/m3, range: 140–775 µg/m3) and occasionally 1 day post-fire when the structure was boarded up before subsequent investigation activities. These results highlight the need to protect investigators’ airways from particulates when fire investigation activities are conducted as well as during post-fire reconstruction activities. Additionally, vapor protection from formaldehyde should be strongly considered at least through investigations occurring 3 days after the fire and personal formaldehyde air monitoring is recommended during investigations.

The Interference from Typical Tire Combustion Products on Gasoline Identification in Forensic Fire Investigations

The Interference from Typical Tire Combustion Products on Gasoline Identification in Forensic Fire Investigations

Biological monitoring for exposure assessment of volatile organic compounds by Korean firefighters at the fire site.

The VOCs and metabolites in urine for exposed VOCs were evaluated for firefighters who participated in the actual fire fighting to determine whether firefighters were exposed to hazardous chemicals, which is the basic data on cancer risk of firefighters. When the fire extinguishing time is long, the concentration of benzene, PHEMA, and toluene among VOCs and metabolites in the case of fire suppression, rescue, and fire investigation work, which is estimated that the exposure of hazardous substances generated from the fire site at the time of fire suppression was large, significantly increased. In the case where the number of urination is 2 or less, the concentration of TZCA, toluene, and benzene among VOCs and metabolites was significantly increased compared to the number of urinating more than 2 times. In the concentration of VOCs and metabolites in urine corrected with creatinine, the concentrations of toluene and PHEMA in urine were significantly higher. The concentration of PHEMA in urine was higher in the group who participated in the fire suppression for more than 11 hours (long time) than the group who participated in the fire suppression for a short time.

Investigation of fires in a mechanically ventilated compartment using the CFD code FireFOAM

The outbreak of fires in nuclear power plants is a major risk due to the potential leak of radioactive materials. The use of traditional prescriptive fire safety regulations has shown its limitations and there is now a shift towards performance-based fire safety engineering, which requires well-validated fire models. Nuclear power plants require the use of mechanical ventilation, which provides dynamic confinement for nuclear materials by maintaining the required pressure. The occurrence of fires could potentially result in pressure variations within power plants. Although dynamic confinement along with other safety measures are in place to prevent fires, there is a continuous need to assess fire safety measures and reduce the risk of fire propagation with the use of fire simulation codes.The current study aims to build on existing research by making use of an emerging open-source computational fluid dynamics (CFD) fire simulation code known as FireFOAM, to predict fire behaviour in a mechanically ventilated nuclear compartment. An existing in-house modified version of FireFOAM developed by the authors’ research group, is further modified in the present work to include a Conjugate Heat Transfer (CHT) model to account for the heat transfer between combustion gases and solid boundaries. The CHT is validated using the experimental wall temperatures and heat fluxes. Furthermore, a mechanical ventilation model has been developed and implemented into FireFOAM. This newly modified version of FireFOAM is employed to predict the pressure variations in a nuclear compartment and the flow rates in the ventilation network. The predictions are compared to some experimental data from the open literature. Overall, it is shown that the mechanical ventilation model and the modified FireFOAM with CHT can predict the pressure variations and flow rates with a relatively good level of accuracy.

Interference from combustion residues of polystyrene-butadiene involving ‘alkylbenzenes’ in molecules on gasoline identification

ABSTRACT The interference of background at fire scene on identification of ignitable liquid residues (ILRs) is an ongoing concern in fire investigation. The current study aims to determine potential interference on gasoline identification from the combustion/pyrolysis products of polystyrene-butadiene rubber (SBr) involving ‘alkylbenzenes’ in molecules. Gas chromatography–mass spectrometry (GC/MS) analysis results of extracts from combustion residues of SBrs, SBrs loaded with gasoline and gasoline were compared. Commonly encountered compounds interfering gasoline identification, including the alkylbenzenes, naphthalenes, as well as indanes, were obtained in all the combustion residues of the SBrs by analysing the extracted ion chromatogram (EICs) of the combustion/pyrolysis products. Furthermore, for gasoline loaded onto SBr substrate, the SBr causes significant distortion to gasoline combustion residues by changing the comparative contents of the target compounds for gasoline identification. Overreliance on the target compounds for gasoline identification could lead to misidentifications in the presence of SBrs combustion residues, while the typical ratios of the target compounds in gasoline combustion residues would also be affected when encountered with SBrs, especially for the cases of smaller loading of gasoline. A detailed examination of the C3-alkylbenzenes and C4-alkylbenzenes profile should be part of any fire debris analysis.

Application of the Framework for Fire Investigations in Informal Settlements to large-scale real fire events – Consideration of fire formation patterns, fire spread rates and home survivability

In recent years, there has been a growing number of projects on informal settlement (IS) fire research, which has been primarily focused on understanding the fire dynamics in IS through full-scale experiments. However, much less is known about real IS fire incidents. Recently, a Framework for Fire Investigations in Informal Settlements (FFIIS) was developed. However, the FFIIS has not been applied to real IS fire incidents yet. This paper seeks to conduct fire investigations by applying the FFIIS to three real fire events. One of them was recorded by a CCTV camera and was analysed in depth in previous work. The video footage was used to benchmark the findings obtain using the FFIIS. The application of the FFIIS allows one to develop hypotheses that more accurately define the area of fire origin and pattern formation sequence. This implies that the fire pattern for large post-flashover fires in ISs can be treated as wildland fires pattern, as proposed by the FFIIS. Additionally, spread rates and the impact of dwellings’ separation distances, in these incidents, are studied. Understanding the limitations and the quality of the information that can be obtained when applying the FFIIS is fundamental to improve the guidelines proposed.

The most remarkable interference to gasoline identification from polystyrene-co-butadiene and the corresponding cause

The identification of ILRs in fire investigations has attracted great attention for decades, and background at fire scenes caused complex interference on ILR identification by contributing characteristic compounds. Aiming at exploring the correlation between the interference extent to gasoline identification and chemical composition/structure, two polystyrene-butadiene rubbers (SBr) with typical styrene contents involving alkylbenzene in molecules were selected particularly. The free burning residues in the presence and absence of gasoline were collected and analyzed via gas chromatography-mass spectrometry. It is striking that SBr with typical styrene content caused the most remarkable interference to gasoline identification as far as reported since it is even impossible to be distinguished from gasoline through chromatography profiles. Additionally, the molecular structure together with the chemical composition influences the interference extent as well. To trace the source of the remarkable interference from SBr, polystyrene, polybutadiene, as well as one polystyrene-butadiene-styrene block copolymer, were picked particularly due to their specific chemical relations. The results of target compounds analysis on the corresponding combustion residues revealed that the remarkable interference of SBrs originated from the combination of 'styrene' and 'butadiene' by contributing different target compounds. The results provide further support for the proposal of the correlation of the interferents chemical compositions with the interference extent. Furthermore, this study provides important references for fire debris analysis by predicting the interference of different substrates on the basis of their chemical composition.

Metallurgical Analysis as a Useful Method for Fire Investigation: the Case of Galvanized Steel Sheets

In this work, fire simulations were carried out on zinc-coated steel sheets usually employed for the structural parts of furniture, transformer rooms and aeration pipes. The thermal alteration induced by the fire was simulated by heating samples at 13 different temperatures (from 20° C to 1050° C) and for different exposure times (1 h and 6 h) in a laboratory furnace. The metallurgical investigation concerned the surface coloring by photographic analysis, the morphology and chemical composition of the surface oxides by SEM and EDS and the microstructure modifications as a function of the temperature by LOM. The influence of the different parameters was discussed by a statistical approach. The obtained results allowed to associate the temperature to one or more alteration of the steel microstructure and of the color, the morphology and the chemical composition of the surface oxides.

‘The coldest case of all’

During excavations of the Viking-age ring fortress Borgring, Denmark, traces of a devastating fire was uncovered. The National Forensic Services of the Danish Police were invited to participate in a novel collaboration, applying contemporary forensic fire investigation to an archaeological site. This paper presents the results and sets a benchmark for future applications. The investigation leads to a revised reconstruction of the fortress and the development of the fire. The application of fire investigation methods, following the Daubert standard criteria, enhance the documentation and analysis of archaeological sites, while archaeological methods show significant potential at modern fire scenes.

A case study on deterioration assessment and rehabilitation of fire damaged reinforced concrete structure

Fire is one of the most severe hazards that building structures may experience during their lifetime. A fire spread to the whole structure can cause unexpected damages to the structural elements. Mainly, the building type is crucially important for the type and the level of damage to the building because of the fire. Post fire investigation of damaged structure is required to determine the extent of damage to concrete elements and to work out system of effective repair/rehabilitation measures to maintain the structural integrity of fire effected structural components. The paper covers in brief the strength and durability study on fire damaged building in Delhi, India. The study reports the extent of fire damage. Optical Microscopy (OM), X-Ray Diffraction (XRD) and Deferential Thermal Analysis (DTA) studies were carried out on the sample concrete cores extracted from different identified portions of the fire exposed concrete are highlighted in this paper. Extent of damage occurred in the Reinforced Cement Concrete (RCC) i.e. RCC columns/beams/slabs are described based on the detailed evaluation by various Non-Destructive Evaluation Techniques covering Cover study & Ultrasonic Pulse Velocity (UPV) testing. Repair and remedial measures required for restoration and strengthening of the fire affected RCC columns/beams/slabs using indigenously available repair materials and techniques are also highlighted in this paper.

A case study on deterioration assessment and rehabilitation of fire damaged reinforced concrete structure

Fire is one of the most severe hazards that building structures may experience during their lifetime. A fire spread to the whole structure can cause unexpected damages to the structural elements. Mainly, the building type is crucially important for the type and the level of damage to the building because of the fire. Post fire investigation of damaged structure is required to determine the extent of damage to concrete elements and to work out system of effective repair/rehabilitation measures to maintain the structural integrity of fire effected structural components. The paper covers in brief the strength and durability study on fire damaged building in Delhi, India. The study reports the extent of fire damage. Optical Microscopy (OM), X-Ray Diffraction (XRD) and Deferential Thermal Analysis (DTA) studies were carried out on the sample concrete cores extracted from different identified portions of the fire exposed concrete are highlighted in this paper. Extent of damage occurred in the Reinforced Cement Concrete (RCC) i.e. RCC columns/beams/slabs are described based on the detailed evaluation by various Non-Destructive Evaluation Techniques covering Cover study & Ultrasonic Pulse Velocity (UPV) testing. Repair and remedial measures required for restoration and strengthening of the fire affected RCC columns/beams/slabs using indigenously available repair materials and techniques are also highlighted in this paper.

Development of Training Scenario Content for On-Site Commanders through Analysis of Response Failure Factors

The aim of this study was to develop training content to strengthen the response capabilities of on-site commanders in actual fire sites. By analyzing past fire cases with insufficient fire responses during firefighting activities, it was determined that analyzing the causes through fire investigations and their corresponding responses is an important step. In addition, although identical fire occurrence situations cannot be reproduced, the causes and responses could be categorized similarly. In this study, the various problems occurring frequently during firefighting activities and factors affecting the response failures were analyzed according to the main causes of fires by building type. Thus, various training scenarios were developed and applied based on the above considerations.

Analysis on the Need for Establishing Fire Investigation & Evaluation Professional Engineer System and Relevant Feasibility

Analysis on the Need for Establishing Fire Investigation & Evaluation Professional Engineer System and Relevant Feasibility

FORENSIC INVESTIGATION OF FIRE AND EXPLOSIONS

In forensics, the investigation of intentional fires, generated by criminal violations of prevention rules, committed out of revenge, in order to hide other crimes, through vandalism, due to mental disorders or in the case of self-ignition in public in order to obtain claims. In forensics, fires and explosions are analysed according to the causes that produce them and according to the substances or devices that initiated and maintained their combustion or explosion.

Juridical Analysis of Government Employees Investigators’ Authority Fire Department Institutions in Fire Investigations

so far, in the regulations for the establishment of Fire Department institutions contained in the Jakarta City governor regulation number 264 of 2016 concerning the organization and work procedures of the Fire Department of Jakarta, it is stated that one of the tasks of the Fire Department, especially in the ranks of the city/regency sub-dept, mandates fire investigations. or it can be interpreted as a fire investigation, but after the authors have reviewed so far from various sources that have the results of questions and answers and their experience there are still many limitations of civil servant investigators to carry out investigations in the pre-investigation stage and until the fire investigation process, these limitations are generally related to the protection of civil servant investigators themselves and their authority in full processing in investigations. civil servant investigators are certain civil servant officials based on statutory regulations appointed as investigators and have the authority to conduct criminal investigations. the results of this study are expected to provide input to the parties in determining the extent to which fire investigation arrangements are based on statutory provisions, and position in the function and role of civil servant investigator of Fire Department in the process of investigating fire occurrence. so that every time a fire occurs, fire officers must be able to carry out fire investigations and not be carried out by other agencies. therefore, it is very necessary to have a law that regulates the duties, principals, functions, and responsibilities of Fire Department institutions and does not depend on other institutions to carry out fire investigations so that the cause of the fire is not only guesswork but is based on an investigation of facts at the scene of the case.

Firefighting of Li-Ion Traction Batteries - An Update

<div class="section abstract"><div class="htmlview paragraph">SAE paper 2013-01-0213 [<span class="xref">1</span>] described firefighting tests with Li-Ion traction batteries. However, additional knowledge and experience has been gained since then. In 2018 and 2019, DEKRA Accident Research and the Department of Anesthesiology of the University Medical Center Göttingen conducted crash tests far beyond standard with four battery electric vehicles. Three of the vehicles’ batteries were used to test a new method of firefighting. A specially designed lance was used to pierce the battery housing, which enabled water to be directly fed into the housings themselves. The method proved to be very effective, but the tests also showed some limitations. The information gleaned from this series of tests and experience gained from other tests was used as a basis for the formation of a multidisciplinary group of experts. The group consisted of representatives of several fire departments, state fire schools, the automotive industry, a medical doctor, accident researchers, fire investigators, DEKRA Accident Research and EV experts. Relevant basic information was collected and incorporated into an information sheet. This was published in German and English on the website of the German Statutory Accident Insurance for firefighters. The paper gives a brief overview of the crash tests, the damage sustained by the batteries (no post-crash fires) and describes the extinguishing tests and their results. The contents of the information sheet are presented and explained.</div></div>