1997; Carman 2008; Gorbett et al. Match. Processes that identify thresholds needed for fire patterns to be identified can be better defined through experimental work or pattern recognition studies. 2010). The burns were intended to be identical to determine if differences would be discovered with a close analysis of the results. 1997). Gypsum wallboard is a common structural lining material consisting of a core of gypsum (calcium sulfate dihydrate) sandwiched between two paper facers (McGraw and Mowrer 1999). Consequently, the forensic scientist must interpret and present the significance of the evidence to the court of law (Taroni et al. There have been many references to penetrations through floors within the early texts on fire investigations, but few provided any guidance on how to interpret from the damage if the fire was moving up through the hole or down. Next, the ability to identify clusters of damage was evaluated. Recording and Statistical Corporation, Canada, Riahi S (2012) Development of Tools for Smoke Residue and Deposition Analysis. Hydrostatic pressure differences at the ventilation opening cause the hot gases to exit the compartment and cooler air to be transferred into the compartment, assuming no external force is causing a greater pressure. The first discussion on this came in the form of discussing beveling or loss of mass (DeHaan 1983). However, an assumption can be made for fuel-controlled fires that higher temperatures will occur at the plume interface with any building or contents surface. Investigations Institute, Florida (USA), Biedermann A, Taroni F, Delemont O, Semadeni C, Davison A (2004) The evaluation of evidence in the forensic investigation of fire incidents (Part I): an approach using Bayesian networks. The results for the eight tests that did not reach full-room involvement were reported as having asymmetric fire patterns and heat damage was consistent with the location of the exposure fire for all but one pre-flashover exposure fire test (Hoffmann et al. The job of a forensic scientist is to provide scientific evidence, notably the analysis of scientific or engineering data, to the justice system in order to reduce uncertainty (Taroni et al. (1991) witnessed a 5070% decrease in peak heat flux values when small standoff distances (0.050.25m) were employed. As this smoke collides with cooler surfaces, it may deposit out of the heated gases onto wall, ceiling and content surfaces. The elements of the fire pattern definition are further explained here: distinct area of damage or cluster of fire effects the area of damage must be clearly distinguishable from other areas of damage through the identification of line(s) of demarcation. As discussed in Section 2.3.1.1, those surfaces that have direct flame contact will have the highest heat flux exposure, followed by fire plumes near surfaces. More experienced fire investigators would mentor less experienced fire investigators, unfortunately in some cases, passing on what has since become realized as a collection of myths (NFPA 2014). 1982; Mealy et al. When the gases rise and expand, they begin interacting with the lining surfaces and contents in the flow of the fluid. He then indicates that the contextual circumstances should also be evaluated, which include a relationship to other artifacts and associated casual factors (proximity to a fuel item), post-flashover conditions and proximity of damage to a ventilation opening. One of the most important findings is that combustion was found to occur detached from fuel items and found to burn nearest the open ventilation source if the global equivalence ratio () in the fire room becomes larger than unity, typically between 1.2 and 1.6 depending on temperature (Thomas and Bennets 1999; Utiskul 2007). J of Forensic Sci. However, not all fire investigators have the same level of education and training, or appreciation for the interaction of the fire in its environment. The majority of this review is of North American work. However, Kirk cautioned that investigators should not place more than casual emphasis on placing a direct relation between char depth and time of burning due to the number of variables that could influence the findings and the lack of reliably controlled test data available (Kirk 1969). Arson investigators were surveyed about how they investigate fires and cited interpretation of alligatoring as one of the most common methods of establishing arson. The Schroeder study (1999), however, was the first to quantify the depth of calcination and its relationship within fire investigations. The velocity of this air inflow also influences this mixing. There were two windows and one door, where one window was closed and the other open for the fire duration, while the door was opened 5min post-ignition. Abib A, Jaluria Y (1992a) Turbulent penetrative and recirculating flow in a compartment fire. repairs of the drywall performed). From this work, Ngu developed a tool based on a constant spring force and a force probe. 2013). Shanley et al. 2013). 2006). The gauge is capable of reading measurements to 0.0005 (0.01mm). National Fire Protection Association, Quincy (USA), NFPA (2008) NFPA 921-Guide for Fire and Explosion Investigation. Carman reports on three tests conducted at ATFs fire research laboratory in a follow-up to his 2008 work (Carman 2010). Duxbury, California (USA), Cooke R, Ide R (1985) Principles of Fire Investigation. The fundamental items within the definition that may assist in better defining the term fire pattern is that patterns are something that happens in regular and repeated ways with characteristic features. Previous fire pattern research by the National Institute of Justice (NIJ), the National Institute of However, all of this is dependent on the burning regime and where combustion is actually taking place at the point in time during the fire when the fuel was ignited. Consumption is a function of heat transfer and the material properties. 2003). soot), and gaseous byproducts, including carbon monoxide (CO), carbon dioxide (CO2), hydrogen cyanide (HCN), oxygen (O2), steam (H2O vapor), and unburned hydrocarbons (UHC). Fire effects are the physical or chemical changes that occur to different materials when exposed to the byproducts of combustion (e.g. National Research Council, Washington, D.C. (USA), Oullette J (2008) ATF FRL Fire Test Report 3589, 3593, 3595. Volume I, National Bureau of Standards, NBSIR 802054, Gaithersburg, MD, Raiffa H (1968) Decision Analysis. plastics, wood) will result in either physical or chemical changes. The earliest texts on fire investigation expressed the importance of using damage and fire patterns in determining the area of origin (Rethoret 1945; Straeter and Crawford 1955; Kennedy 1959; Kirk 1969). [1], This developmental curve reflects the progression of intuitive thinking processes as a person develops more advanced knowledge structures in a specific area. The authors have since noted several limitations to this exercise including that the participants were not permitted to complete a full investigation of the compartment, were not allowed to move any items and had to make a conclusion based on their visual interpretation of the damage from the doorway. National Institute of Standards and Technology, NIST GCR 07907, Utiskul Y, Quintiere J (2005) Generalizations on Compartment fires from Small-scale experiments for low ventilation conditions. The average velocity of natural buoyancy driven flows or natural ventilation through the bottom of a door during ventilation-controlled conditions is approximately 1.52.0m/s (3.44.4 mph) (Kerber 2010; Quintiere and McCaffrey 1980). Once these parameters are identified and organized, various techniques can be applied to facilitate the collection of critical information, analysis of the data and facilitation of a decision. The characteristics that are proposed here include the type, magnitude, direction and proximity (e.g. Investigations Institute, Florida (USA), Hopkins R, Gorbett G, Kennedy P (2009) Fire Pattern Persistence Through Post-Flashover Compartment Fires. The use of 2 springs running parallel to each other allows for equal pressure on each side of the tool (Fig. Comparing Delichatsioss (1984) simple correlation of flame height for wall fires to the average damage height identified in Madrzykowskis study shows that the calculated flame height under-predicted the damage height by approximately 711% for the natural gas burner and gasoline fires. This misconception was so ingrained in the profession that it was repeated as fact in the Fire Investigation Handbook published by the National Bureau of Standards (Brannigan et al. He found that the damage from the flame plume would extend approximately the width of the fuel for 100kW fires that did not have a ceiling jet form and 3 times the width of the fuel with 300kW fires that did have flame extension under the ceiling. 2007-DN-BX-K236. National Institute of Justice, Grant # 2007-DN-BX-K240, Wood C, Simeoni A, Foley R (2012) Preliminary Results of the Effect of Carpet Pad Seams Compared to Ignitable Liquid Pours, Floor Fire Patterns in Post-Flashover Fires, Paper presented at the International Symposium on Fire Investigations. 1977; Brannigan et al. U-shaped development can be seen in cognitive skills such as learning new words, or doing high-level algorithms in mathematics. The study concluded that 73.8% without measurable data and 77.7% with measurable data accurately determined the area of origin. 1997). 2013). 2008; NFPA 2014). Schroeder was able to illustrate that a crystalline change would occur within the gypsum wallboard when heated by using an x-ray diffraction technique. The forces bearing on the fire were identified in this text as (a) combustibles involved, (b) openings and ventilation, (c) winds and drafts, (d) explosions and (e) variations from normal burning. Soot deposited in rooms away from the room of origin have a fairly uniform soot deposition on all surfaces extending from floor to ceiling (Wolfe et al. In March of 1997 four full-size compartment test fires were conducted in furnished bedrooms (Milke and Hill 1997). Also, their study noted that similar areas of great magnitude of damage occurred around doors and on walls opposite door openings. The legal and science professions are currently scrutinizing forensic science, which is forcing the nation to question the disciplines scientific foundation (NIJ 2009). NFPA 921 states that there are three basic causes of fire patterns: heat, deposition and consumption (NFPA 2014). Gorbett, G.E., Meacham, B.J., Wood, C.B. However, Schroeders study did not produce an effective means for implementing this method into a scene inspection. These gases are buoyant compared to the surrounding air at the opening interface, which causes them to flow through the opening, unless there is wind or some other external force (mechanical ventilation) allowing the pressure outside of the compartment to be higher. https://doi.org/10.1186/s40038-015-0008-4, DOI: https://doi.org/10.1186/s40038-015-0008-4. Their study reported that the fire damage to the surface and internal cross section of the wallboard occurs progressively in the following manner: Discoloration/degradation of facing paper; Partial dehydration and discoloration/soot staining of surface layer of gypsum; Formation of anhydrous and hemihydrate layers with layers progressing through the cross section; Complete conversion of dihydrate to anhydrous and hemihydrate; Anhydrous extends through the entire cross section; Wallboard becomes catastrophically heat damaged and lacks structural integrity. The LEAA report, after listing the indicators, identified that these indicators have received little or no scientific testing and that there appears to be no published material in the scientific literature to substantiate their validity (Boudreau et al. Despite the lack of validity and this caution, the training and textbooks within the profession during this time used these indicators as a means to link an observation to the speed of the fire and ultimately to the conclusion of fire cause. First Asian Conference on Fire Science and Technology, China, Quintiere J (1995) Compartment Fire Modeling. An upholstered sofa and upholstered chair were located in adjacent corners across the room from each other with a coffee table in between. The authors stated that fire leaves its fingerprints and that each finger of flame leaves its effects and the study of these effects will help you pick the spot where it burned first (Straeter and Crawford 1955). The movement of smoke from a compartment into an adjoining space is controlled by the density differences at the interface of the ventilation opening. Plenary Paper Presented at the International Symposium on Fire Investigations. The upper layer gases are elevated in temperature and have the ability to radiate heat downward onto the tops of contents throughout the compartment. Forensic Science International 147:4957, Boudreau J, Kwan Q, Faragher W, Denault G (1977) Arson and Arson Investigation-Survey and Assessment. They also discussed that locations and conditions of ventilation openings as functioning in two different capacities, where the fire could pass to the next roomor it may be a source of incoming air to feed the fire (Straeter and Crawford 1955). The ULG patterns are characterized by level lines of demarcation (or lines with similar elevation) with a generally uniform degree of damage (NFPA 2014). 2006; Hicks et al. As floor patterns were warned against, so has floor penetrations by both the fire science and investigation communities (Babrauskas 2005; NFPA 2014). This section has been divided into four subsections that evaluate the general location and type of fire patterns. Ngu performed simple bench top tests to evaluate this tools ability to reliably obtain depth measurements. In addition, this study identified that greater damage (clean burn) occurred at the seams between drywall sections within their tests when they were not covered with tape and mud, due to leakage through the unsealed openings. It was reported, many of the investigators had difficulty finding the location of the point of origin, in many cases indicating the opposite side of the room (Custer and Wright 1984). This was the first published work that outlined how to develop a legend and diagram as demonstrative aids for applying the heat and flame vector analysis. An optical measurement method was developed to arrive at optical properties of smoke deposited out of a smoke layer onto glass filters. The more significant issue with ventilation-generated patterns is when the compartment fire is ventilation-controlled. 2013). The central theme is that the investigator can section off a room and can use the location of ventilation openings as a predictor of the location and magnitude of damage based on the location of this ventilation and the predicted airflow from these openings. Hicks et al. The science of interpreting burn patterns is considered important by fire investigators when establishing a fire'sarea of origin. (2013). Fire investigators have used geometric shapes, such as truncated cones, triangular, columnar, conical, v-shaped, u-shaped and hourglass-shaped patterns since the early 1940s (Rethoret 1945). Terms in this set (60) Fire effects. Fire Protection Research Foundation, Quincy, MA, NFPA (2004) NFPA 921-Guide for Fire and Explosion Investigation. Of course, apex is actually the antonym of the word desired here. Fire Science Reviews The term or similar terms were later defined in subsequent texts as where the fires destruction took place and where it did not (DeHaan 1983). 2003). The evolution in terminology clarifies how fire patterns became a more restricted definition and it is this bounded term that will be the focus of this literature review section. Shanley et al. 3). Fire investigators are instructed to visually and measurably identify these areas and lines of demarcation. The statistics can be found in Additional file 1 associated with this review paper. In 1997 The United States Fire Administration (USFA), in conjunction with the National Institute of Standards and Technology, Building and Fire Research Laboratory (NIST-BFRL) launched the fire pattern research committee and produced the USFA Fire Pattern Test report (Shanley et al. Location and elevation are essentially further describing proximity. This was observed in rooms, which had flashover conditions where clean burn areas were produced under windows away from the origin. Instrumentation included thermocouples in the gas layer and under the flooring material. Several researchers supported this analysis but questioned the practical application of such a method (Schroeder 1999; Kennedy et al. Underwriters Laboratories, Illinois (USA), Kerber S, Walton W (2005) Effect of Positive Pressure Ventilation on a Room Fire. 2012). The majority of these texts stated that the investigator should consider the damage to be caused by an ignitable liquid if the investigator would visibly observe damage to the floor in the shape of a puddle, have hard-edged burn marks in the shape of a pour, or the damage had the appearance of trailers (i.e. A better definition is warranted for this term. Both tests resulted in an area of greatest damage directly across the room from the window opening, the opposite side of the room from the true origin. 10). National Institute of Standards and Technology, Grant 60NAN81D1142, Gaithersburg, MD, Schroeder R (1999) Post-Fire Analysis of Construction Materials. Saito (1993); Williamson, et al. Consequently, these two factors combine to inflict more damage and create more pronounced fire effects near the plume centerline, with the damage decreasing as the distance from the centerline is increased (Jowsey 2007). Various types of fire patterns, such as; "V-shaped", "hour-glass", and "inverted cone", have come from common observation at actual fire scenes. Example of a Heat and Flame Vector Analysis Diagram (fire origin located in center of couch-fire test conducted at EKU by author). Fire and Arson Investigator Journal of the International Association of Arson Investigators 11:1518, Crofton, MD, Kirk P (1969) Fire Investigation. Forty-eight tests were conducted with a standardized ANSI/UL wood crib and ten additional tests were conducted with commercially available polyurethane foam recliners. The related lines of demarcation are ensuring that the area being called a pattern have associated boundaries or lines of demarcation. This is still a common practice in fire investigations with these undamaged areas termed protected areas. 2008). Examples of Fire Patterns: "Inverted Cone". The concept of fire patterns for this review has been broken into four components that better assist in evaluating their effectiveness in determining an area of origin. The ventilation of the compartment for suppression is a common activity by fire department personnel, typically performed by opening doors and windows. statement and As expected, the results indicated that the patterns generated by the polyurethane foam fire had greater uncertainty than the natural gas and gasoline pool fires. (2013) designed a tool based on the previous work of Ngu (2004), which used a force gauge with an attached hex key probe (2mm diameter). The first attempt at consolidating patterns was the first edition of NFPA 921, however many misconceptions had spawned up between the early 1960s and the publication of NFPA 921 (NFPA 1992). Several correlations have been developed to assist in determining the minimum HRR necessary for flashover to occur, conditioned on the total surface area of the compartment (AT) and the ventilation factor \( {A}_v\sqrt{h_v} \) (McCaffrey and Quintiere (1977); Babrauskas 1980; McCaffrey et al. This pattern is not an accurate indicator of an accelerant, or arson. A coffee table in between influences this mixing quot ; Inverted Cone quot. Interpretation of alligatoring as one of the compartment B.J., wood, C.B arrive optical. The type, magnitude, direction and proximity ( e.g would be discovered with a standardized wood! Nfpa 921 states that there are three basic causes of fire Investigation Analysis questioned! Is not an accurate indicator of an accelerant, or arson and its relationship fire. Ma, NFPA ( 2008 ) NFPA 921-Guide for fire patterns: & quot ; Inverted Cone & ;. Area being called a pattern have associated boundaries or lines of demarcation are ensuring that area. 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Personnel, typically performed by opening doors and windows in a follow-up to his 2008 work ( carman 2010.! Through experimental work or pattern recognition studies optical measurement method was developed to arrive at optical properties of deposited! Concluded that 73.8 % without measurable data accurately determined the area being called pattern!
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