Examples of Fire Patterns. Annotated by Robert A. Corry Director, Fire Investigation Specialist American Re-Insurance.Classic "V" "Inverted Cone" on a Wall "Inverted Cone" on an Object. Abib A, Jaluria Y (1992a) Turbulent penetrative and recirculating flow in a compartment fire. From this work, Ngu developed a tool based on a constant spring force and a force probe. The variances in composition and fire performance of different types and different manufacturers will be something that requires further research. Holes in floors have had many misconceptions tied directly to floor patterns, as discussed previously. 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. Alternative explanations are now commonly given when discussing penetrations through floors, including: radiant heat, furniture items, melting plastics and pre-existing openings in the floor during fully involved compartment fire (NFPA 2014) (Fig. The following statistics were accumulated while performing the literature review and summarized here for ULG fire patterns. Wiley, California (USA), Kleindorfer P, Kunreuther H, Schoemaker P (1993) Decision Sciences: An Integrative Perspective. 2012). Test Data from Published Full-Scale Fire Pattern Tests and Statistics for Fire Pattern Generation. 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. Some of their more notable findings was that floor patterns caused by ignitable liquids may be minimal because they can easily be destroyed, that the commonly reported clean burn damage may be caused by water spray from fire suppression hoselines and that areas of clean burn were associated with the inflow of air due to local ventilation flows. 1997). A conical pattern has been characterized as one that is produced when the interacting buoyant fire plume is restricted by an intersecting horizontal surface, spreading the heat across the bottom of the obstructing surface. This quote, however, is not to generalize that the area of origin is to be equated with the area of greatest thermal damage outside of this specific test series. [1], Last edited on 10 November 2021, at 10:13, https://en.wikipedia.org/w/index.php?title=U-shaped_development&oldid=1054493463, This page was last edited on 10 November 2021, at 10:13. Currently, no systematic method exists for fire investigators to identify a fire pattern. Source: Guide to Wildland Fire Origin and Cause Determination, PMS 412. Lines of demarcation are the borders defining the differences in certain heat and smoke effects of the fire on various materials. The more significant issue with ventilation-generated patterns is when the compartment fire is ventilation-controlled. (2006; 2008) conducted a fire pattern reproducibility study using single fuel items. When a fire develops in an enclosure, the products of combustion (e.g. The second part isolates the work conducted on identifying fire patterns and the characteristics associated with these trends within the damage. Proceedings of the 17th International Systems Safety Conference, Unionville, VA, Ettling B (1990) The Significance of Alligatoring of Wood Char. He succinctly describes his process as direction of spread of the fire will be notedit will be upward, partially lateral, rarely downward, but its direction will indicate the general region of origin when properly interpreted. These myths have been dispelled by several studies, but their influence on using the geometric shapes as descriptors has justifiably persisted (NFPA 2014; Shanley et al. predominantly fuel-controlled or ventilation-controlled) produce substantially lower temperatures. Identification of varying DOFD throughout the compartment serves as the basis for interpretation by the investigator. Self-published, California (USA), Stratakis G, Stamatelos A (2003) Thermogravimetric analysis of soot emitted by a modern diesel engine run on catalyst-doped fuel. A literature review was performed in order to achieve the objectives of this study. 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). These researchers proffered that the closer the fuel item burning was to the wall surface, the sharper the contrast and angle to the lines of demarcation and the more likely the damage would resemble a V in shape. From this work, the researchers used gravimetric measurements of these filters to demonstrate and validate an analytical model for smoke deposition based on thermophoresis. Fire pattern that resembles a U or V shape and indicates the direction of fire progression in that area. 10). One of the 11 NWCG categories of fire pattern indicators. National Fire Protection Association, Quincy (USA), NFPA (2001) NFPA 921-Guide for Fire and Explosion Investigation. As the fire continues to develop, the ceiling jet and the gases from the upper layer begin to have an intensified effect on the surfaces nearest the plume. Cox provided a process for better interpreting the compartment fire dynamics that is still under development and has not undergone a major field test for user application. variables: the material itself, the RHR, fire suppression activities, temperature of the heat source, ventilation, and the length of time of exposure. U-shaped development can be seen in cognitive skills such as learning new words, or doing high-level algorithms in mathematics. Fire and Arson Investigator Journal of the International Association of Arson Investigators 64(3):1625, Clemen R, Reilly T (2001) Making Hard Decisions. The level of damage was varied based on the visible appearance of the number of cracks within set distances and the widths of those cracks. The Law Enforcement Assistance Administration (LEAA) documented many of the myths about using the visible appearance of damage to identify arson (Boudreau et al. Beginning in March of 2005, a series of 20 full-scale fire pattern tests were conducted at Eastern Kentucky University (Gorbett et al. This suggests that many investigators have received the majority of their training through informal on-the-job training. %PDF-1.5 % 1980; Keith and Smith 1984; King 1985; Ettling 1990). The focus of this literature review is to identify the work that has been done specifically for forensic applications that have been conducted for identifying ways to observe and characterize varying degrees of fire damage through measurable or visible means. (2010)). The compartments were 12ft by 12ft with 8ft ceiling heights (3.6m3.6m2.4m) with a single door opening 3ft by 6ft-10in. Each test fire was conducted for 10min, with the door opened at 5min. For example, if an investigator observed charred wood with large, rolling blisters giving it the appearance of alligator skin, then the fire investigator was to interpret this as a rapid fire which was often used then used in concluding that the fire was incendiary in nature. After another period of time the skill once again ascends to a higher position on the y-axis. The tool used constant force springs to ensure an even, consistent pressure is applied at all times regardless of the user. Noticeable patterns created by the fire as it burns. Ventilation-Generated Fire Pattern near open doorway (fire origin located across room-fire test conducted at EKU by author). Correct determination of the origin depends on the correct. Investigations Institute, Florida (USA). 2, SFPE Handbook of Fire Protection Engineering, 4th edn. Ngu performed simple bench top tests to evaluate this tools ability to reliably obtain depth measurements. There was no significant damage identified around the window ventilation, as the researchers discussed that this vent served primarily as an outflow for the heated gases, while the doorway served as the inflow due to the location of the neutral plane. 2010). In 2011 three test fires were conducted that varied between single and multiple ventilation openings (Claflin 2014). 1977). First, during fuel-controlled conditions ventilation has been shown to cause the fire plume to lean away from the source of ventilation due to momentum flows from the inflow, thus influencing the truncated cone shape (Shanley et al. As this smoke collides with cooler surfaces, it may deposit out of the heated gases onto wall, ceiling and content surfaces. NFPA 921 (2014) discusses that plume-generated patterns typically have characteristics associated with geometric shapes. 4). Of course, apex is actually the antonym of the word desired here. 2012). For example, the clean burn effect requires wall temperatures to reach approximately 450500C and should be evaluated as possibly exposed to a plume (Stratakis and Stamatelos 2003). Andrew Cox (2013) argues that both the generic causal factors and the contextual circumstances should be considered when interpreting the cause of the damage. Prior to discussing the patterns themselves and their historical progression, it is first important to recognize that lines of demarcation or areas of demarcation serve as the borders of a fire pattern and should be defined. 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. fire patterns); Interpreting the causal factors for the generation of the fire patterns; and. 2007; Madrzykowski and Fleischmann 2012). This area of damage opposite the door had angled lines of demarcation that extended from the floor to the ceiling. Chemical changes include the decomposition/pyrolysis, dehydration, or changes in color. Mann and Putaansuu (2010) exposed samples of gypsum wallboard to three levels of heat flux for three different durations and noted visible changes, as well as depth of calcination changes with a variety of probing instruments. Liquids Versus Melted Solids. These included that soot deposition can be used to aid in the area of origin determination and that the clean burn area size was proportional to the fire size (Wolfe et al. They are examples only, not models. The damage that would result would be dependent on the location of the origin of the plume and distance to the intersecting obstructions. Given these findings, damage cues 1, 2 and 3 are used as the most accurate damage cues for classifying a fire pattern generated by upper layer. As the gases rise and expand, they also begin to interact with ventilation openings. This study also developed a simplified grid system out of tent pole stakes to decrease scene processing time. 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). Again, Kennedy makes the argument that the investigator needs to identify the greatest area of damage. As such, the recognition and identification of lines or areas of demarcation and the elevation changes with those lines of demarcation capture the essence of these shapes without using geometric shapes as universal descriptors. However, no formal procedure has been developed, including: how to determine a direction, how to incorporate compartment fire dynamics into the process and how to make an area of origin conclusion based on the results. 2006; Hicks et al. The sides exposed to the direction from which the fire is coming will be more severely burned and charred. Director, Fire Investigation Specialist. Floor patterns were found lacking in many of the fire pattern tests where the compartment transitioned to a fully involved state (Shanley et al. The majority of the experimental work has been conducted in small, residential-sized compartments with one or two ventilation openings. Proceedings of The 3rd International Conference on Performance-Based Codes and Fire Safety Design Methods, SFPE, Bethesda, MD (USA), Mealy C (2013) Ignitable Liquid Fuel Fires in Buildings A Study of Fire Dynamics. Barnott et al. The fourth part of the review focuses on the practice of using damage in fire investigation to assist in determining the area of fire origin. Fire and Arson Investigator Journal of the International Association of Arson Investigators 64:1833, Gorbett G, Morris S, Meacham B, Wood C (2014) A new method for the characterization of the degree of fire damage to gypsum wallboard for use in fire investigations. In ventilation-controlled conditions, cue 1 was the most positively identified in 82% of the studies (37/45), cue 2 was identified in 73% of the studies (33/45), cue 4 was identified in 64% of the studies (29/45), cue 6 was identified in 62% of the studies (28/45), cue 3 was identified in 53% of the studies (24/45), and cue 5 was only identified in 11% of the studies. The prescribed process by Mealy (2013) was time consuming due to the requirement on the user to be extremely careful in watching the gauge and then marking the probe with a piece of tape to document the depth, thus introducing potential error. In ventilation-controlled conditions, cue 1 was the most positively identified in 87% of the studies (39/45), cues 25 were identified in 76% of the studies (34/45), cue 6 was identified in 62% of the studies (28/45), and cue 7 was only identified in 42% of the studies (19/45). 1977). It was not until 2008 that NFPA 921 changed the definition of the term with the introduction of the term fire effects. 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). To accomplish this, the researchers evaluated the variability of the flame height in comparison to the height and area of damage. [2] In 2009, Wolfe, Mealy and Gottuk conducted 15 full-scale tests with varying ventilation conditions and fuels. by 6ft, 8in. The compartments were of frame construction with unfinished wood lining the interior of the compartment. This will leave a series of burned studs, which serve as pointers or arrows to trace the fire (Kennedy 1959). The pointer theory was proffered as a system of determining the point of origin of a fire by tracing its path back to its sourcethe system is based on the fact that fires normally travel by feeding on flammables. The background section establishes the foundation for the organization of this paper. Fire investigation (origin and cause determination) is an integral part of the total fire safety model, including fire prevention and protection for a community. The bulk of this research can be found within the SFPE Engineering Guide, Assessing Flame Radiation to External Targets from Pool Fires (SFPE 1999). This is the reason that many fire investigation texts commonly refer to fire moving up and outward (DeHaan and Icove 2011; Kennedy 1959; Kennedy (1977); Kirk 1969; Rethoret 1945). The literature on using fire patterns to determine an area of origin should be classified into four areas that will assist in guiding future research, including: Assessing the varying Degrees of Fire Damage (DOFD) along the surfaces of the compartment and contents (i.e. A survey was conducted to evaluate the proficiency of professional fire investigators at determining the area of origin when provided with photographs and measurable data from a test (Tinsley and Gorbett 2013). In 2003, ten full-scale test burns were performed in a ISO 9705 room 12ft by 12ft with 8ft ceiling heights (3.6m3.6m2.4m) with a primary focus on examining television sets and electronic appliances exposed to a full-scale room fire (Hoffmann et al. This pattern is not an accurate indicator of an accelerant, or arson. 1985). Terms in this set (60) Fire effects. International Association of Arson Investigators 5:119120, Crofton, MD, Kennedy J (1959) Fire and Arson Investigating. Finally, the study was conducted with a variety of digital cameras and they found that the optical properties were not dependent on the camera used. 2014). Fire investigators commonly use the lack of thermal damage behind or under contents, known as protected areas, as evidence that the damage was caused by an upper layer. Gypsum wallboard is one of the more common lining materials for walls and ceilings used for construction of residential and commercial facilities. Theobald (1968) performed a series of experiments with target combustible items (wood blocks, cotton cloth and plywood) located at 0.45m and 0.9m above the floor at various lateral distances away from a variety of common residential fuel items burning, such as a kitchen chair, easy chair, arm chair, bookcases and wardrobes. The authors do not, however, indicate how, provided this information, an investigator arrives at a conclusion. However, he found that much higher charring rates apply to floors and to any other wood members where charring is affected by the presence of gaps or joints. These results support the use of standardized processes to decrease the variability in data collection and interpretation. Arson A fire started deliberately Fire Triangle Info represents the three elements, needed for fire to occur: heat, fuel, and oxygen Fuel + Oxygen + Heat = Fire Fuel Characteristics distilled from the literature related that the ULG patterns will have level lines of demarcation with relatively uniform magnitude of damage, unless the upper layer is flowing from one location to another and, if so, the lines of demarcation will be angled towards the opening. 80 0 obj <> endobj This study provides an understanding of the fire risk of building's exterior wall geometry design at different altitudes. fire effects); Identifying clusters and trends of damage (i.e. This pattern has been associated with a fuel package that has the potential HRR to overcome the thermal inertia and start a pyrolysis reaction in the surface material, thereby creating the pattern, but insufficient energy to produce a plume which reaches any horizontal restriction above the fuel package (Hicks et al. NFPA, Quincy, MA, pp 3.1253.133, Quintiere J, McCaffrey B (1980) The Burning of Wood and Plastic Cribs in an Enclosure. 12). 2013) (Fig. Decision analysis has its roots in operations research, where it emerged from a desire to better understand and address decision-making under uncertainty, becoming viewed as a unique area of study in the 1960s (Howard 1966; Raiffa 1968). Their example is as follows, if the investigator decides he has located a seat of fire within a radius of error of 1m, he is certain that the original seat of fire lays within an area having one metres [sic] radius (i.e. However, the authors did not propose a working prototype. (1997)) and Gorbett et al. Developing a process for the objective identification of areas requiring further attention during fire investigation that is universally accepted by the community is recommended to increase the reliability and accuracy of fire origin determinations. Another problem is that the shapes discussed are assuming an idealized fire plume that is shaped as a cone, which is a gross oversimplification. This limitation of the flaming combustion allows for the production of smoke. Smoke contains particulates, liquid aerosols and gases (NFPA 2014). (2013) identified hose spray from suppression efforts as washing off areas of soot and ash from the gypsum wallboard, leaving behind a white area. Jaluria Y ( 1992a ) Turbulent penetrative and recirculating flow in a compartment.... Within the damage performed in order to achieve the objectives of this paper tests were conducted varied. Pms 412 higher position on the correct ( 1993 ) Decision Sciences: an Integrative Perspective doing high-level in... Performed in order to achieve the objectives of this paper will be something that requires further research of... Ventilation conditions and fuels is coming will be something that requires further research multiple ventilation (... 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