Even if these gases were burned when they came out of the opening, thermal damage to the wall surface is expected to follow the same theory . The resulting damage appears to be angular delineation lines with the lower end of the delimitation line closest to the source of the smoke stream (Fig. 12). Since heat transfer mainly depends on a temperature difference, larger temperature differences will result in a larger heat flow. In a compartment fire, the highest temperatures are present in those places where combustion occurs. The column of fire and the various heat flows it generates are one of the most important means of causing damage in the early stages of a fire due to this large temperature difference and very turbulent flows.
Fire is likely to not only destroy physical evidence, but water and chemical foam used to extinguish the fire can also destroy potential evidence. As a result, the main witnesses of an arsonist are the firefighters who come to the scene for the first time. The researcher will ask firefighters for details such as smoke color, damaged spray systems, door and window condition and generally Fire Expert Witness California strange flame behavior. After establishing the behavior of the fire, investigators will look for the starting point and any other physical evidence that can be documented. This allows them to reconstruct the event and use the scientific method to test or refute arson. One of the challenging aspects of fire research is the multidisciplinary basis of the researcher’s work.
This method or a similar method should be further investigated using the work done for the plasterboard (Gorbett et al. 2014). The following identified trial was conducted by John Kennedy in 1962 and was called Pointer of Arrow Theory . The popping theory was presented as a ‘system to determine the starting point of a fire by returning the path to the source … The sides exposed to the direction from which the fire comes will be burned and charred more severely. ” . Again, Kennedy states that the investigator must identify the largest damage area. Kennedy wrongly assumes that “when burning with buildings or other structures where wooden beams or asparagus are exposed and burned, the application of fire will generally be constant.” . The characteristics of the damage related to the cartridges generated by ventilation during the conditions controlled by ventilation are large surfaces and greater damage, angled demarcation lines around the ventilation opening or directly opposite the opening of a door.
Variations in fire composition and performance of different types and different manufacturers will be something that requires more research. No studies have been conducted to evaluate these patterns, but some of the features of these patterns have been identified in other fire pattern studies. Shanley et al. ) reported that the patterns generated by the suppression caused by spraying water from a fire brigade hose line were easily recognizable in their test series. Water spray damage consisted of many elongated stripes, less than 1 inch long and grouped and oriented so that they looked like a spray pattern. This study also noted that it was clear that the water was not deposited all material outside the wall or ceiling surface, was washed because “the patterns were lighter in color than the environment, but not as light as a clean or protected combustion area ” (Shanley et al. 1997). Some studies have been conducted that specifically evaluated the creation of the fire pattern on the floor (Putorti 2001; Mealy et al. 2013).
He encouraged researchers to focus on burns, as it says “every low point should be explored as a potential source of combustion.” . Kirk also identifies many of the “very common complications” that may arise, which “will distract the investigator from following the fire pattern to its origin.” . These deviations from “normal” patterns, as he called them, include areas of open ventilation, secondary ignition of falling material, roof or attic fires, open air fires and roof collapse. It will rarely be upward, partly lateral, downwards, but the direction will indicate the area of general origin when interpreted correctly. The combustion that fire researchers will find most often is predominantly diffusion flams. Combustion of a fuel by diffusion flams is inherently oxygen limited by the diffusion reaction and the availability of only 21% oxygen in the air in well-ventilated fires.
Even if a compartment is broken by opening a window or door or due to a structural collapse, the influx of oxygen can cause an explosion known as a flashhover caused by ventilation. As explained in this method, two-dimensional shapes and patterns would be formed by the general three-dimensional plume when crossing these surfaces, resulting in V and U-shaped patterns on walls, content and vertical and radially shaped structural members. These researchers offered that the closer the fuel element burn was to the wall surface, the more sharp the contrast and angle to the demarcation lines was, and the damage more likely resembled a V-shape. The more the fuel element burns from the wall surface, the demarcation lines, on the other hand, would be more subtle and round at U-shaped angles. Kennedy and Kennedy were also the first to propose that the damage should take the form of a triangle, columnar, or conical shape after the flame plume had crossed a wall surface in a compartment.
A premeditated fire investigator investigates a fire to determine whether it was accidental or deliberate. Arsonists are law enforcement officers who work for law enforcement agencies or fire departments. His responsibilities include collecting evidence, interviewing witnesses and identifying potential suspects. These techniques include collecting physical evidence and processing that evidence in a laboratory. A visible degree of fire damage scale was developed for the plasterboard and it was shown that it reduces variability in beginners who classify different degrees of fire damage on a wall surface (Gorbett et al. 2014).
The direct solutions currently listed for the causes of fire patterns include plume-generated patterns, patterns generated by layers of hot gas, patterns generated by ventilation and suppression-generated patterns . The thermophoretic forces between the gas and the surface lining are highly dependent on the combustion regime of fire. In the early stages of a fire and due to fuel-driven conditions, the production of incomplete combustion by-products is usually lower. Higher temperatures and higher smoke speeds mean that more soot deposits are formed at certain locations in the compartment.