Gypsum wallboard is one of the more common lining materials for walls and ceilings used for construction of residential and commercial facilities. Many of the suppression factors would not necessarily develop new patterns that have unique characteristics. Wood and gypsum wallboard (drywall) were the only materials that had sufficient literature to review in this context. 4. Characteristics of the damage linked with ventilation-generated patterns during ventilation-controlled conditions are large surface areas and increased magnitude of damage, angled lines of demarcation located around the ventilation opening or directly opposite of a door opening. 2002) and forensic analysis (Taroni et al. Interpretation of the causal factors for the generation of the fire patterns was next appraised. The fire pattern studies revealed that specific damage cues identified during fuel-controlled conditions were not as prevalent during ventilation-controlled conditions. (2004) had flames resulting from a lack of mixing within the compartment, which has also been identified in compartments with combustible linings (Drysdale 2011). 1997). The literature review is limited to structure fire studies. However, no procedural details were provided on how to implement the analysis. Only one article was identified related to the use of visible char appearance in identifying varying DOFD where quantitative measures were attempted (Keith and Smith 1984). As the gases rise and expand, they also begin to interact with ventilation openings. Drysdale (2011) indicates that the average compartment temperatures are highest near the cross over between fuel-controlled and ventilation-controlled. He encouraged investigators to focus on low burns, because as he says any low point in a burn should be investigated as a possible origin (Kirk 1969). As the compartment transitions through flashover and into full-room involvement, the upper layer descends toward the floor and encompasses nearly the entire volume of the compartment. 2009-DN-BX-K232. 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). Such data include the patterns produced by the fire (NFPA 2014). The focus of his process was similar to the others in describing that the area of origin will be located at the greatest area of damage and the investigators should focus on identifying the low burn damage areas and using conical shapes. None of these texts, however, provided a methodology to the reader on how to go about identifying what constitutes greater and lesser visible or measurable char damage. 1982; Mealy et al. Forensic science is defined as the application of a broad spectrum of sciences to answer questions of interest to the legal system, including both criminal and civil actions (Houck and Siegel 2006). Investigation Institute, Illinois (USA), Kennedy, Kennedy (1985) Fire, Arson and Explosion Investigation. In 2011 three test fires were conducted that varied between single and multiple ventilation openings (Claflin 2014). 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. Incident heat flux to wall, floor, or ceiling surfaces is dependent on the HRR of the fuel and standoff distance between the flame plume and the surface of interest. This warning was strengthened over the years to say irregular, curved, or pool shaped patterns on floors and floor coverings should not be identified as resulting from ignitable liquids on the basis of observation of the shape alone (NFPA 2001). The fire investigation community terms the resulting damage as fire effects, which are defined as the observable or measurable changes in or on a material as a result of exposure to the fire (NFPA 2014). Ventilation-generated fire patterns have been described in the literature as having a slight influence during fuel-controlled conditions, but become the predominant issue with the location and magnitude of damage after the compartment fire is ventilation-controlled (Shanley et al. 1980). 1997). 7, 8 and 9). However, fire investigators currently use their visual interpretation to give vague descriptions on the varying degrees of damage when reporting their findings. This damage is commonly reported as heat or smoke deposition reported to be found throughout a structure at varying heights on the walls of a room between areas of no damage and smoke or heat damage. National Fire Protection Association, Quincy (USA), NFPA (2008) NFPA 921-Guide for Fire and Explosion Investigation. 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. It is important for reliability and validity that the industry develop processes to assist investigators to objectively identify fire patterns. The presence of a soffit and the size of an opening influences the depth of the damage within the compartment, however, as the compartment nears flashover damage begins to occur at lower elevations on all surfaces. Gregory E Gorbett. 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). Cookies policy. Together these make up the fire triangle. Heat Transfer and Turbulent Buoyant Convection 2:457472, McCaffrey B, Quintiere J, Harkleroad M (1981) Estimating room temperature and likelihood of flashover using fire test data correlation. Most recent studies consider taking the actual depth of calcination by using an instrument and probing it into the wall a more effective method (Mann and Putaansuu, 2010; Mealy and Gottuk, 2012; Kennedy et al. 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. 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. The compartment size, ventilation opening and setup were similar to the 2008 work. irradiances measured 0.05m away range to near 80kW/m2 for the fastest burning specimens; however, 40kW/m2 was not recorded farther than 0.44m away and 20kW/m2 was not found beyond 0.88m distant. 1997; Wood et al. However, some data exists that indicates if a compartment fire does not transition to a fully involved state, then the floor patterns may persist (Putorti 2001; Mealy et al. variables: the material itself, the RHR, fire suppression activities, temperature of the heat source, ventilation, and the length of time of exposure. Airflow from a ventilation opening has been shown in previous compartment fire studies to cause flames to lean over significantly and that the influence of this factor decreases as the plume is moved back away from the vent (Steckler et al. These early definitions are broad and all encompassing of the entire fire scene. The statistics can be found in the Excel Spreadsheet associated with this review paper. The three tests were conducted with identical contents and ventilation. Addison-Wesley, Reading, MA, MATH The upper layer gases are elevated in temperature and have the ability to radiate heat downward onto the tops of contents throughout the compartment. Dillon (1998) went on to illustrate that some of the corner flame height approximations resulted in 40% uncertainty, but others were as close as 2%. Saddle burns display deep charring. Section 3, Ch. Thermocouple data and total heat flux gauges were used as instrumentation for all three burns. The researchers consequently provide guidance to investigators on how to resolve this situation by saying it is necessary to pay particular attention to low burns and shadow effects on room furnishings (Custer and Wright 1984). 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. Varying degree of fire damage to gypsum wallboard-visible damage results, Varying degree of fire damage to gypsum wallboard-contour plot of the depth of calcination results of Fig. 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. Finally, an area that is white in color surrounded by soot areas should not be classified as a clean burn area until closer examination is performed. All of the fire pattern studies have been summarized in Additional file 1. Barnott et al. [4], The U-shaped development in physical skill comes from the development and recession of muscular strength, on the graph the Y-axis is muscular strength and the X-axis is time. 1997; Carman 2008; Gorbett et al. 2003). Most of the earlier literature supported the idea that specific patterns were indicative of causal links or to the speed of the fire, which was mostly linked to incendiary fires (e.g. Flashcards. The researchers noted differences and attributed these to small variations in the inflow of air. 2012). The rooms were instrumented with heat flux gauges, thermocouples and gas sampling probes. 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). truncated cone patterns. Proper fire investigation should determine the fire cause, the cause of the resulting property damage and most importantly, the cause of bodily injury or loss of life to civilians and firefighters. National Bureau of Standards, U.S. Department of Commerce, Washington, D.C. (USA), Carman S (2008) Burn Pattern Development in Post-Flashover Fires. This area of damage opposite the door had angled lines of demarcation that extended from the floor to the ceiling. These studies contended that the use of the heat and flame vector analysis enabled the investigator to determine the true area of origin. The ULG patterns are characterized by level lines of demarcation (or lines with similar elevation) with a generally uniform degree of damage (NFPA 2014). long lines of damage appearing to spread the fire from one location to another). In all cases, ignition of a gasoline spill next to an upholstered chair was used to initiate the fire. Interscience Communications, London (UK), Meacham B (2000) Application of a Decision-Support Tool for Comparing and Ranking Risk Factors for Incorporation into Performance-Based Building Regulations. Paper presented at the International Symposium on Fire Investigations. 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. Accelerants Substances, such as gasoline, paint thinner, and alcohol, that accelerate the burning process. The damage caused by this upper layer is often times referred to as hot gas layer-generated fire patterns or heat and smoke horizons (NFPA 2014; DeHaan and Icove 2011), but in this work it will be described as upper layer-generated patterns (ULG patterns). within an area of 3.14 square metres [sic]) (Cooke and Ide 1985). The inverted cone or triangular pattern resembles an upright triangle with the vertex at the top. 14). Obviously this misconception was widespread as Kirk identified that it was not uncommon for the investigator to assign the cause to the use of a flammable liquid (Kirk 1969). This combination of using damage in the context of the fire behavior variables was new to the profession in 1955, but then apparently lost for the next 40years. As a result, the observations are typically qualitative in nature. Protected Surface: Body "Clean Burn" "Rundown Burn" Ignitable Liquid Pour Pattern. NFPA 921 further lists that fire patterns can be classified by their generation or causal relationship to the fire dynamics by providing the following classes: plume-generated patterns, ventilation-generated patterns, hot gas layer-generated patterns, full-room involvement-generated patterns and suppression-generated patterns (NFPA 2014 ). 2013). Identifying the cause of the damage is complicated by the fact that the investigator has to use evidence after the event, such as the location and magnitude of damage, compartment geometry, ventilation openings and the position and number of fuels as a means to identify the range of initial conditions that may have influenced how the fire developed. 2012), Testing photograph for carpet pad seam generation of pattern similar to reported ignitable liquid pour showing burning in exposed surface resulting from carpet pad shrinkage (Wood et al. An optical measurement method was developed to arrive at optical properties of smoke deposited out of a smoke layer onto glass filters. 1, 4th edn. 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. Since the beginning of fire investigations, the focus on how to determine the area of origin for a fire was to try and use damage to work backwards in an attempt to recreate the development of the fire within the investigators mind. Fire Technology 49:395409, Saito K (1993) Study of Fire Induced Flow Along the Vertical Corner Wall. 1. 2007; Jarman et al. 2007; Hopkins et al. Fire effects are the bases for the varying DOFD that was discussed in the previous section. 2004). J of Forensic Sci. Kirk being one of the few texts at the time that opposed this idea when declaring flammable liquids never carry fire downward (Kirk 1969). A visible degree of fire damage scale (DOFD) was developed for gypsum wallboard and was shown to decrease variability in novices ranking varying degrees of fire damage across a wall surface (Gorbett et al. The researchers stated that one of the objectives of their tests was to determine if burn patterns in the room were consistent with the origin or location of the external fire (Hoffmann et al. Glossary Tag: WFISC PMS412 Given these findings, damage cues 1, 2 and 4 are used as the most accurate damage cues for classifying a fire pattern generated by ventilation. [3], This U-shaped curve is different from the other types of skill development because this skill has an artistic rating with it, which means there could be differences in opinion, but in studies where children, adult artists, and non-artist adults were all given the same directions to draw a self portrait, the children's and the artists' were the closest of the three to depicting the face when picked by an outside group. Charles C. Thomas Publisher, Illinois (USA), Francis J, Chen A (2012) Observable characteristics of flashover. 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