sill height (0.812m). Several researchers supported this analysis but questioned the practical application of such a method (Schroeder 1999; Kennedy et al. Plenary Paper presented at the International Symposium on Fire Investigations. Hughes Associates, Maryland (USA), Bieber P (2014) Anatomy of Wrongful Arson Conviction: Sentinel Event Analysis in Fire Investigations. Fire Safety Science-Proceedings of the 1st International Symposium, New York, NY, pp 129139, Taroni F, Bozza S, Aitken C (2005) Decision analysis in forensic science. This type of damage was noted in the USFA study with specificity (Shanley et al. First, a poor assumption by many of the fire investigation guides, textbooks and research was that every investigator is able to visibly assess varying DOFD equally (Shanley et al. Fire and Arson Investigator Journal of the International Association of Arson Investigators 7:1618, Crofton, MD, Straeter R, Crawford C (1955) Techniques of Arson Investigation. A standardized depth tool needs to be implemented to decrease error, similar to the one developed by Barnott et al. 2006; Hopkins et al. He lists causal factors for this white area of damage as possibly hose stream wash, surface paper burned off leaving a clean noncombustible surface behind, or the wall may have been surfaced differently prior to the fire (i.e. A "U" shaped time line is created of the skills development. Fire Technology 39:207224, Hopkins R, Gorbett G, Kennedy P (2007) Fire Pattern Persistence Through Post-Flashover Compartment Fires. Illustrations from this first discussion are still found today in the current edition of NFPA 921 showing a cross-section of a floor with greater beveling or loss of mass indicating direction (NFPA 2014). NFPA 921 is recognized as establishing the standard of care for the fire investigation profession and is the only consensus document that exists for fire investigators. Use of damage in fire investigation: a review of fire patterns analysis, research and future direction, https://doi.org/10.1186/s40038-015-0008-4, http://ncfs.ucf.edu/twgfex/docs/Scene_Survey_Results.pdf, http://www.forenseek.org/spip/?A-Decision-Support-System-for,46, www.Merriam-webster.com/dictionary/pattern, https://creativecommons.org/licenses/by/4.0. 2013). Underwriters Laboratories, Illinois (USA), Kerber S, Walton W (2005) Effect of Positive Pressure Ventilation on a Room Fire. It was once thought that narrow V-patterns were produced by a fast developing fire and wide V-patterns were produced by a slow developing fire (Kennedy and Kennedy 1985). Fire investigators are instructed to visually and measurably identify these areas and lines of demarcation. The three tests were better instrumented with three total heat flux gauges, one radiant heat flux gauge, three gas sensors (measuring O2, CO2, CO), and gas velocity probes (Oullette 2008). 2003). 2002) and forensic analysis (Taroni et al. The results confirmed that the use of this method was appropriate for these three test fires (Shanley et al. predominantly fuel-controlled or ventilation-controlled) produce substantially lower temperatures. Their use of this method was stated to ensure that an investigator would be required to provide an indication of the degree of accuracy, as well as provide an area for excavation. Section 5, Ch. Thirty-nine novice raters performed an analysis of damage to a wall surface, completing 66 ratings first without the DOFD method and second, repeated rating with the new DOFD method. This production of incomplete combustion byproducts is exacerbated in poorly ventilated spaces, ventilation-controlled burning regimes and combustion of fuels that under normal atmospheric conditions have high soot yields (e.g. 2007-DN-BX-K236. Particulates and aerosols are commonly deposited on the wall and ceiling surface where the upper layer interacted with the lining surface (NFPA 2014). The effects that remain after a fire are typically related to the damage resulting from the cumulative heat flux received by an exposed material. Babrauskas (1981) reports on ignition of secondary items based on burning a series of common residential fuels and evaluating the heat flux to transducers at varying lateral distances. Springer Nature. Forensic Science International 147:4957, Boudreau J, Kwan Q, Faragher W, Denault G (1977) Arson and Arson Investigation-Survey and Assessment. Their method encouraged investigators to use fire patterns to arrive at an origin, but upon arriving at their hypothetical area(s) of origin required the investigator to provide some measure of accuracy in the form of a radius of error. NFPA 921s original publication followed this trend and warned, irregular, curved, or pool shaped patterns on floors and floor coverings cannot always be reliably identified as resulting from ignitable liquids on the basis of observation alone (NFPA 1992). Drysdale (2011) indicates that the average compartment temperatures are highest near the cross over between fuel-controlled and ventilation-controlled. The same proponents of identifying pour patterns as being indicative of an ignitable liquid, also promulgated that holes in floors were indicative of ignitable liquids being used (Battle and Weston 1960; Fitch and Porter 1968; Barracato 1979; Smith 1983; Harmer et al. Mealy et al. Test 1 had the window and door open for the entire duration of the fire, test 2 had the window hinged closed until flashover and then the window was left opened for the duration of post-flashover and test 3 had no window. Multiple carpet pads were tested. The presence of a ventilation opening is necessary. Google Scholar, Babrauskas V (1981) Will the second item ignite? All of the early texts indicate that fire tended to rise and that a pattern may exist from this damage, but most did not use the term pattern nor did they give any guidance on what a pattern was (Rethoret 1945; Kennedy 1959; Kirk 1969). Ngu (2004) performed similar experimental work as Schroeder (1999). Fire and Arson Investigator Journal of the International Association of Arson Investigators 9:3235, Crofton, MD, Taylor R (1986) Flammable and Combustible Liquid Characteristics in Certain Types of Fires Part 2. %PDF-1.5
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They are examples only, not models. The cumulative heat exposure should be considered the leading factor in the creation of damage. Ultimately, the locations of damage and fire patterns are compared to the causal factors from the physics of the fire, alternative causes and background information. Arson investigators were surveyed about how they investigate fires and cited interpretation of alligatoring as one of the most common methods of establishing arson. In their report, authored by its Research Council on Post-Fire Investigation, they recommended, if patterns are to be used for origin and cause determination, forensic methods to identify the specific source of a pattern need to be developed and rigorously vetted (NFPA, 2002, p.5). As floor patterns were warned against, so has floor penetrations by both the fire science and investigation communities (Babrauskas 2005; NFPA 2014). Fire Technology 49:395409, Saito K (1993) Study of Fire Induced Flow Along the Vertical Corner Wall. More recent research has identified heat flux values between 25 and 50kW/m2 reported at 1m away from more modern fuel packages, including king size mattresses, upholstered chairs and sleeper sofas (Madrzykowski and Kerber 2009). In addition, if these gases were undergoing flaming combustion as they exited the opening, thermal damage to the wall surface is expected to follow the same theory (DeHaan and Icove 2011). The damage cues evaluated for plume-generated damage included: Cue 1-loss of mass to fuel is consistent with damage to affected surface. Areas of demarcation are locations along a surface that exhibit similar damage characteristics (e.g. The further the fuel item burning was from the wall surface, the lines of demarcation would be more subtle in contrast and would be more round in angle in the shape of a U. Kennedy and Kennedy (1985) were also the first to propose that damage would be in the shape of a triangular, columnar, or conical shape after the flame plume had intersected a wall surface within a compartment. The varying damage was given many terms by fire investigators and is reflected within the literature, including: fire patterns, burn patterns, indicators, burn indicators, fire fingerprints, fire transfer patterns and a variety of geometric shapes. Next, the ability to identify clusters of damage was evaluated. Photograph of a Conical-Shaped Fire Pattern along a concrete block wall (fire origin was located under the stack of wooden pallets-fire test conducted at EKU by author). Later the term morphed into heat shadowing, which was first defined as the effect of an object blocking the convected or radiated travel of heat and flame from its source to the particular surface material which is under examination (Kennedy and Kennedy 1985). 1 and 2). smoke, aerosols). Investigators use the varying heights and direction of the lines of demarcation as indicative of directional flow. 2013; Claflin 2014). Madrzykowski and Fleischmann (2012) completed work on flame plume damage against a gypsum wallboard lined wall and showed that for smaller HRR fuels (2080kW) the maximum width of damage was never greater than 1.5 times the width of the fuel. These patterns are often witnessed on vertical surfaces of content items and wall linings. Investigations Institute, Florida (USA), Hicks W, Gorbett G, Hopkins M, Kennedy P, Hopkins R, Thurman T (2008) Full-Scale Single Fuel Package Fire Pattern Study. The most emphasis was placed on combustibles involved and openings and ventilation. Since 1992, NFPA 921 has established the de facto standard of care for the fire investigation profession, yet it lacks specific procedures for origin determination (Gorbett and Chapdelaine 2014). Saddle burn. The majority of this review is of North American work. Fire research station, Fire Research Note No. Heat exposure to the materials (e.g. However, ventilation becomes one of the more prominent influences of damage when the compartment has transitioned into ventilation-controlled conditions. This can help determine the origin point. Most of these earlier texts, however, do not offer a process on how to use the data, other than vague descriptions on visibly identifying greater areas of damage and tracing fire patterns. 2009-DN-BX-K232. As mentioned before, if the magnitude of damage is changing, but the lines of demarcation are related, then a pattern may still exist. No studies have been conducted specifically to evaluate these patterns, however, some characteristics of these patterns have been identified in other fire pattern studies. Thus, the lining materials for the walls, ceiling and floor, as well as the various materials that make up the contents within the compartment, are damaged by this exposure to the products of combustion. One common type of fire pattern is plume-generated patterns, the lines that come from the three-dimensional shape of the fire plume being cut by an interweaving two-dimensional surface, such as a ceiling or wall. Volume I, National Bureau of Standards, NBSIR 802054, Gaithersburg, MD, Raiffa H (1968) Decision Analysis. In fuel-controlled conditions, cues 24 were positively identified in 92% of the studies (23/25), cues 1 and 5 were positively identified in 88% of the studies (22/25), cue 6 was positively identified in 84% of the studies (21/25), and cue 7 was identified in only 68% of the studies (17/25). The influences of the U-shaped exterior wall geometry on upward flame spread over insulation material on plain and plateau were studied through laboratory-scale experiments. 7, 8 and 9). Fire Pattern Indicator, U or V Fire pattern that resembles a U or V shape and indicates the direction of fire progression in that area. 2012). If the burning fuel package was located away from the witness surface, the resulting fire pattern has been characterized as being in the shape of a U, evidenced by its radial or curved lines of demarcation (Hicks et al. 2004). 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. Clean burn damage also occurred along the wall near the doorway opening in the fire with the longest full room involvement burning duration. The characteristics of damage that have been reported in the literature to assist investigators in determining the cause of the fire pattern will be evaluated here. Average velocities of natural ventilation flows through windows have been recorded between 0.5 and 1.0m/s (1.14.4 mph) depending on the sill height and elevation of the opening within the wall (Kerber 2010; Kerber and Walton 2005; Quintiere and McCaffrey 1980). The fuels used for their experiments included a natural gas burner, gasoline pool fire and polyurethane foam. The following statistics were accumulated while performing the literature review and summarized here for ULG fire patterns. Paper presented at the 8th IAFSS Symposium, London (UK), Vesely W, Goldberg F, Roberts N, Haasl D (2002) Fault Tree Handbook. The tests will be summarized chronologically in this section and will be referred to in other sections of the literature review where the work specifically addresses that subject matter. Fire Safety Science Proceedings of the 3rd International Symposium, Elsevier Applied Science, New York, pp 657667, Wolfe A, Mealy C, Gottuk D (2009) Fire Dynamics and Forensic Analysis of Limited Ventilation Compartment Fires Volume 1: Experimental. Addison-Wesley, Reading, MA, MATH Carman (2008) noted similar areas of damage of great magnitude directly opposite door openings and within the inflow of the air from this door. One aspect of looking at radiant heat flux is to determine if the secondary object has been raised to a critical temperature or is receiving a critical heat flux where ignition of that object is possible. Investigations Institute, Florida (USA), Gorbett G, Hicks W, Kennedy P, Hopkins R (2006) Full-Scale Room Burn Pattern Study. Cue 4-width of base of damage is approximately the width of the fuel item and not greater than two times the width of the fuel item. Historically, fire investigators have been individuals without any formal education or training in scientific methodology. The only point of contention then would be the manner and reason in which the ventilation opening was created. Anyone you share the following link with will be able to read this content: Sorry, a shareable link is not currently available for this article. 2003). Source. Their study noted that clean burn areas were observed on wall surfaces under windows that had opened during the fire and that the damage extended from the sill of the window to the floor. Most of the studies conducted on calcination are limited in their examination of gypsum wallboard variations. fire patterns) in an attempt to reconstruct the fires development. A pattern may encompass the varying DOFD areas as long as the line of demarcation are linked by direction. 1982; Mealy et al. 3). Post-test data collection included examination, photography and a subset of depth of char measurements. Fire investigation texts describe the characteristics of the lines of demarcation associated with a plume-generated pattern as a progression through triangular, columnar and conical patterns. The failure in knowledge transfer is most likely because experienced investigators, particularly those who obtained their basic training before 1992, were trained with misinformation and misconceptions (Lentini 2012). If the burning fuel package is located away from the witness surface, the resulting fire pattern is shaped as a "U", Learn. 2012; Mealy et al. 2003). Often times the soot deposited within the room of origin will be higher in elevation with distinct lines of demarcation and thick soot deposits. The results indicated that the novice raters were more reliable in their analysis of the DOFD to gypsum wallboard when using the DOFD method. SFPE Handbook of Fire Protection Engineers, NFPA, Quincy, MA, Lattimer B, Sorathia H (2003) Thermal characteristics of fires in a noncombustible corner. 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