Both compartments were furnished similarly with a sofa located under the open window, a sofa located along the wall next to the door and a kitchen table in the center of the compartment. 4). 2007; Madrzykowski and Fleischmann 2012). Paper presented at the 8th International Conference, Fire and Materials 2003. When a fire develops in an enclosure, the products of combustion (e.g. Paper presented at the International Symposium on Fire Investigations. In this study, a DOFD scale was developed as a ranking system to reflect the varying degrees of visible fire damage to gypsum wallboard based on its response to heat exposure and visible damage indicators. This article is a third in a series that discusses burn patterns and interpretations when attempting to determine the origin of a fire. A survey was conducted by the National Center for Forensic Sciences (NCFS) in 2000 where 422 fire investigators revealed that only 33% held a college degree, of which only 10% were related to science or engineering (Minnich 2000). Therefore, fire investigators within most fire scenes typically find charred material. 2008; Madrzykowski and Fleischmann 2012; NFPA 2014). A study conducted in 2012 examined the effect of carpet underlayment/carpet pad on post-flashover fire, floor patterns (Wood et al. 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. wood chair) and the pyrolyzates (unburned fuel) will burn in locations near ventilation openings and along airflow paths when sufficient oxygen for combustion exists (Custer and Wright 1984; Shanley et al. Experts actually get down on hands and knees to search for any physical clues, like accelerants, matches, cigarette butts, tire marks, or footprints. However, no procedural details were provided on how to implement the analysis. 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. The damage cues evaluated for upper layer-generated damage included: Cue 1-damage high in elevation on wall surfaces. The system was described as the truncated cone method, which described the fire plume as a three-dimensional cone that would be cut or truncated by the various two-dimensional horizontal and vertical obstructions (i.e. The first of which is the standoff distance between the fuel item burning and the damaged surface. The compartments were 12ft by 12ft with 8ft ceiling heights (3.6m3.6m2.4m) with a single door opening 3ft by 6ft-10in. 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. (1997)) reported that suppression-generated patterns, those caused by water spray from a fire department hose line, were easily identifiable in their test series. There are hundreds of materials that can be found in residential occupancies, as such there are thousands of studies that would need to be reviewed and summarized here to identify the characteristics of the material properties and the impact that heat has on each material. In over 40% of the fire pattern tests, level lines of demarcation attributed to this damage was identified. The sides exposed to the direction from which the fire is coming will be more severely burned and charred. Kirk continues the discussion by cautioning the investigator that this pattern will be altered by the presence of obstructions, or of readily burned fuel in localized areas, and he warns that a very common complication arises when areas of excellent ventilation are present where intense burns will be noted in such areas that may well distract the investigator from following the fire pattern back to its point of origin (Kirk 1969). Also, the study illustrated that drywall seams, if no tape and mud was applied, would present areas of clean burn damage during ventilation-controlled conditions (Mealy et al. Department of Fire Protection Engineering, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA, 01609, USA, Gregory E Gorbett,Brian J Meacham,Christopher B Wood&Nicholas A Dembsey, Department of Fire Protection and Paramedicine Sciences, Fire, Arson and Explosion Investigation Program, Eastern Kentucky University, 521 Lancaster Avenue, Richmond, KY, 40475, USA, FireLink, LLC, 1501 Main Street, Suite 17, Tewksbury, MA, 01876, USA, You can also search for this author in These deviations from normal patterns, as he called them, included areas of open ventilation, secondary ignition of falling material, roof or attic fires, exterior exposure fires and roof collapse. For example, an investigator would assign a number 5 char level to a piece of wood that had the number of cracks occurring up to 2 per centimeter with widths approximately the thickness of a five-cent piece (Keith and Smith 1984). A standardized depth tool needs to be implemented to decrease error, similar to the one developed by Barnott et al. The majority of the experimental work has been conducted in small, residential-sized compartments with one or two ventilation openings. Finally, the availability of processes using fire patterns in determining an area of origin was assessed. Many plastic materials will burn. 2013). As these problems began to be studied, approaches were developed to help individuals and organizations identify the components of a good decision, how to structure the decision problem and how to treat the associated uncertainty (Clemen and Reilly 2001; Donegan 2008; Kahneman and Tversky 1974; Kleindorfer et al. Charles C. Roberts, Jr., Ph.D., P.E. 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). Fire effects are the bases for the varying DOFD that was discussed in the previous section. Investigations Institute, Florida (USA), Mealy C, Wolfe A, Gottuk D (2013) Forensic Analysis of Ignitable Liquid Fuel Fires in Buildings. Therefore, the walls, ceiling and floor surfaces are now receiving an elevated heat flux, in addition to the already burning fuel receiving greater feedback, increasing its own HRR and other fuels becoming involved. Fire and Arson Investigator Journal of the International Association of Arson Investigators 64(1):3747, Custer R, Wright C (1984) Open Windows and Thermal Inversions may Complicate a Fire Investigation. NFPA 921 (2014) discusses that plume-generated patterns typically have characteristics associated with geometric shapes. They identified areas of damage with greater magnitude around the doorway openings. Around the late 1970s there was a movement within the profession to describe fire patterns by descriptions of their geometric shapes (e.g. The flame plume is also the most predominant contributor to damage and ignition of secondary and tertiary contents early in the fire prior to the contribution by the upper layer (Jahn et al. %%EOF
A U-shaped burn pattern found on the top of floor joists, caused by fire burning down through the floor. Cue 2-increased magnitude of damage near the fuel item. The combustion of a fuel through diffusion flames is inherently oxygen limited by the diffusion reaction and the availability of only 21% of oxygen in air in well-ventilated fires. A better definition is warranted for this term. Two 15ft by 15ft (4.57m4.57m) structures with a ceiling height of 7ft (2.13m) were tested. 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). %PDF-1.5
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Cookies policy. 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). Fire and Arson Investigator Journal of the International Association of Arson Investigators 4:5558, Crofton, MD, Steckler K, Quintiere J, Rinkinen W (1982) Flow Induced by Fire in a Compartment. In fact, a recent sentinel event analysis of wrongful convictions found that this one misconception is the most common factor in wrongful arson convictions (Bieber 2014). Correspondingly, this heat source is often attributed to igniting contents throughout the compartment, especially those items located relatively high in elevation around the compartment (e.g. Cue 5-increased area and magnitude of damage under the window. Flashcards. Therefore, the visual identification of color changes through the cross-sectioning of wallboard will not be further addressed. This was also observed on walls opposite door openings (Shanley et al. The correct word is nadir, but to remain consistent with these texts apex will be used. 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). Hicks et al. The only procedural aspect that NFPA 921 provides for fire pattern use for origin determination is the heat and flame vector analysis (NFPA 2014). Typically, flashover occurs at a =1.0 (Wieczorek et al. Combustion Science and Technology 39:195214, Dillon S (1998) Analysis of the ISO 9705 Room/Corner Test: Simulations, Correlations and Heat Flux Measurements. A fundamental principle of decision analysis is that people do not always have all the data or information needed to make a good decision. Often times the soot deposited within the room of origin will be higher in elevation with distinct lines of demarcation and thick soot deposits. 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. Wood stud wall with varying DOFD char damage, Depth of char contour plot of wood stud wall depicted in Fig. (2004) had flames resulting from a lack of mixing within the compartment, which has also been identified in compartments with combustible linings (Drysdale 2011). Created by. Therefore, the approach of this step is to leverage what science currently exists to assist with validating the current list of direct solutions for fire pattern generation and identifying characteristics that may exist and how they may vary with the changing fire dynamics. This misconception persists despite the warnings from both the fire science and fire investigation communities (Shanley et al. SFPE Handbook of Fire Protection Engineers, NFPA, MA, Wieczorek C, Vandsburger U, Floyd J (2004) An evaluation of the global equivalence ratio concept for compartment fires: data analysis methods. They further confirmed the NFPA 921s and Mann and Putaansuus progressive visible damage to the surface of the gypsum wallboard. This study also developed a simplified grid system out of tent pole stakes to decrease scene processing time. A series of nine full-scale studies, funded by the National Institute of Justice, were conducted with ignitable liquid fuel spilled on carpeted and vinyl flooring with varying ventilation scenarios (Mealy et al. Obviously, the damage to the walls remaining after the fire is the cumulative result of all items that burned and the investigator would not be able to tell if the damage witnessed was the first item or a later item burning (e.g. 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). Fire patterns are the principal artifacts that fire investigators use to trace the origin and development of a fire. However, the authors did not propose a working prototype. Test one used only Class A fuels, while the eight remaining tests used gasoline as the first fuel ignited. Cue 4-lines of demarcation are angled emanating from the ventilation opening. variables: the material itself, the RHR, fire suppression activities, temperature of the heat source, ventilation, and the length of time of exposure. Figure 1 is a schematic representation of how such a pattern is created, and Figure 2 shows a triangle-shaped pattern produced by a test fire. From this work, the researchers used gravimetric measurements of these filters to demonstrate and validate an analytical model for smoke deposition based on thermophoresis. Absent the testimony of reliable eyewitnesses to or recording of the fires inception, the investigator is required to determine the origin by observation and expert interpretation of the physical evidence (e.g. Federal Emergency Management Agency, Washington D.C. (USA), Smith F (1983) Gasoline Detection in Hardwood Parquet Flooring Six Days After Total Burnout. This rule of thumb of burning duration had been the source for some misconceptions related to determining if a fire was incendiary and fell into disrepute around the mid-1990s. This limitation of the flaming combustion allows for the production of smoke. Paper presented at the Fire and Materials 2009 Conference. However, no specific details are provided on how to implement this analysis. He then recorded the maximum lateral distances at which the target fuels were scorched, charred, or ignited. Carman (2008) noted similar areas of damage of great magnitude directly opposite door openings and within the inflow of the air from this door. Therefore, it is expected that soot deposition on wall surfaces to be greatest in thickness and higher in elevation closer to the room of origin and lesser in thickness and lower in elevation as one moves away from the room of origin. Because the varying DOFD serves as the foundation for all later interpretations, ultimately leading to an origin determination, more research is needed to either demonstrate that investigators reliably identify varying DOFD or the industry needs processes that are shown to be reliable and valid (Gorbett and Chapdelaine 2014). 2013). This type of damage was first identified as being helpful at determining the area of origin by Straeter and Crawford (1955). The fire plume is typically the highest temperature zone within the compartment, which can lead to significant damage (Beyler 1986; Lattimer 2008). In 2009, Wolfe, Mealy and Gottuk conducted 15 full-scale tests with varying ventilation conditions and fuels. fire patterns) in an attempt to reconstruct the fires development. National Fire Protection Association, Quincy (USA), NFPA (2014) NFPA 921-Guide for Fire and Explosion Investigations. Fire and Arson Investigator Journal of the International Association of Arson Investigators 2:8082, Crofton, MD, Heskestad G (1982) Engineering relations for fire plumes. Wall condition on the four sides of a room may differ and thus indicate where most heat was applied (Straeter and Crawford 1955). 2012), Resultant floor burn pattern from carpet pad seam without use of ignitable liquids (Wood et al. 2013). PubMedGoogle Scholar. ATF, Ammendale, MD, Pattern (2015) Merriam Webster Dictionary. 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). Aetna Life and Casualty, Connecticut (USA), Battle B, Weston P (1960) Arson: A Handbook of Detection and Investigation. Kirk being one of the few texts at the time that opposed this idea when declaring flammable liquids never carry fire downward (Kirk 1969). 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. Several studies concerning ventilation-controlled fires throughout the years have introduced a concept of a ventilation factor (\( {A}_v\sqrt{h_v} \)) and illustrated the importance of ventilation openings on a fires growth by analyzing the size of ventilation openings, locations of these openings within the compartment and the shear mixing that occurs at the interface of the opening (Kawagoe 1958; Thomas and Heslden 1972; Harmathy 1972; Thomas and Bennets 1999; Utiskul 2007; Sugawa et al. Nuclear Regulatory Commission. Several recent studies have provided processes to assist in the objective identification of the varying degrees of damage, including a degree of fire damage scale for visible damage (Gorbett et al. Largely parallel vertical lines of demarcation and a HRR sufficient to reach any horizontal restriction above the fuel package have been provided as the reason for columnar patterns (NFPA 2014). Investigations Institute, Florida (USA), Hopkins R, Gorbett G, Kennedy P (2009) Fire Pattern Persistence Through Post-Flashover Compartment Fires. Addison-Wesley, Reading, MA, MATH Encyclopedia Britannica Company, Chicago, www.Merriam-webster.com/dictionary/pattern, Pitts W (1994) The Global Equivalence Ratio Concept and the Prediction of Carbon Monoxide Formation in Enclosure Fires. 2014). Google Scholar, Rethoret H (1945) Fire Investigations. The early texts on fire investigations promoted the use of identifying the varying degree of charring throughout the compartment to assist with origin determination. The origin of both fires was located under the window in the sofa, but different accelerants were used to start each test fire with 2-gallons of gasoline in test 1 and scattered newspaper in test 2. Pearson, New Jersey (USA), DeHaan J (1987) Are Localized Burns Proof of Flammable Liquid Accelerants? Grant No. Six tests were completed with television sets placed inside a wood entertainment center. The ventilation of the compartment for suppression is a common activity by fire department personnel, typically performed by opening doors and windows. It is suggested from this literature review that the overall reasoning process for evaluating fire damage for determining an area of origin consists of the following seven steps (Gorbett 2015): Identifying the value in further analysis of a surface or compartment; Identification of the varying degrees of fire damage (DOFD) along the surfaces of the compartment and contents; Identifying clusters and trends of damage (fire patterns); Interpreting the causal factors for the generation of the fire patterns; Testing the hypothetical area(s) of origin; and. (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). predominantly fuel-controlled or ventilation-controlled) produce substantially lower temperatures. There are four logical components to the literature review presented: The first part of the review describes the work completed for establishing a degree of fire damage assessment for commonly encountered materials in structure fires. He concluded that it was possible to identify the quantity of fuel used by the burn area. Correspondence to Therefore, no systematic scale for the degree of damage had been proposed or adopted. (1991) witnessed a 5070% decrease in peak heat flux values when small standoff distances (0.050.25m) were employed. The degree to which materials are influenced by the developing fire will be a function of the material characteristics, temperature of the products of combustion and the duration of exposure (NFPA 2014). 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