FIA2

FIR 4305, Fire Investigation and Analysis 1

Course Learning Outcomes for Unit II Upon completion of this unit, students should be able to:

2. Evaluate a fire scene in accordance with fire industry best practices and legal requirements. 2.1 Describe the challenges an investigator faces when conducting a cause and origin

investigation. 2.2 Identify fire suppression activities that may impact a fire investigation.

Course/Unit Learning Outcomes

Learning Activity

2.1 Unit Lesson Chapter 5 Unit II Research Paper

2.2 Unit Lesson Chapter 5 Unit II Research Paper

Reading Assignment Chapter 5: Fire Scene Examination

Unit Lesson In Unit I, you learned about the scientific method and developed an understanding of its importance for a professional fire investigation. Using this nationally accepted methodology gives the fire investigator a foundation from which to build an investigation. The next step in this process is developing a standardized approach to each fire investigation that will ensure consistency and help prevent the overlooking or misinterpretation of key factors that may lead to the cause and origin of a fire. This is a very difficult task because, unlike other possible crimes where evidence is generally created by the crime, in a fire, the evidence of a possible crime is actually being destroyed as the fire progresses. The table below covers all of the steps that you should be covering during every fire investigation. It does not matter if the cause of the fire appears to be due to something simple, such as food being left on the stove; regardless, a professional investigation should take place from the reference of the investigator not having any preconceived notion of the cause of the fire. This is a very difficult aspect of investigating a fire, especially as you gain more experience and expertise in this field. The investigation must remain free of bias, and fire investigators must avoid forming opinions based solely on the information provided by the incident commander and the first-in suppression crews. Additional information that leads to a possible crime often comes days, weeks, or even months after the suppression activities are completed.

Category Job Performance Requirement

4.1 General Requirements for a Fire Investigator

4.1.1 Shall meet the job performance requirements defined in Sections 4.2 through 4.7 4.1.2 Shall employ all elements of the scientific method as the operating analytical process throughout the investigation and for the drawing of conclusions

UNIT II STUDY GUIDE

Examining the Fire Scene

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4.1.3 Site safety assessments shall be completed on all scenes, and regional and national safety standards shall be followed and included in organizational policies and procedures 4.1.4 Shall maintain necessary liaison with other interested professionals and entities 4.1.5 Shall adhere to all applicable legal and regulatory requirements 4.1.6 Shall understand the organization and operation of the investigative team within an incident management system

4.2 Scene Examination 4.2.1 Secure the fire ground. 4.2.2 Conduct an exterior survey. 4.2.3 Conduct an interior survey. 4.2.4 Interpret effects of burning characteristics on materials. 4.2.5 Interpret and analyze fire patterns. 4.2.6 Examine and remove fire debris. 4.2.7 Reconstruct the area of origin. 4.2.8 Inspect the performance of building systems. 4.2.9 Discriminate the effects of explosions from other types of damage.

4.3 Documenting the Scene 4.3.1 Diagram the scene. 4.3.2 Photographically document the scene. 4.3.3 Construct investigative notes.

4.4 Evidence Collection and Preservation

4.4.1 Utilize proper procedures for managing victims and fatalities. 4.4.2 Locate, collect, and package evidence. 4.4.3 Select evidence for analysis. 4.4.4 Maintain a chain of custody. 4.4.5 Dispose of evidence.

4.5 Interview 4.5.1 Develop an interview plan. 4.5.2 Conduct interviews. 4.5.3 Evaluate interview information.

An investigation can begin during a fire, immediately after the fire is extinguished, during the clearing of the scene, or after the cleanup. All of these are acceptable, but in general, arriving sooner rather than later to start the investigation is recommended. Some of the benefits of arriving while the fire is ongoing would include being able to see the fire progression; observe suppression activities that may interfere with or affect the investigation; find witnesses, as they have a tendency to walk away—especially if there is the possibility of crime involvement;

Table 2.1: Professional levels of job performance for fire investigators (Icove & Haynes, 2018)

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and speak with and influence the incident commander about trying to preserve areas, minimizing damage from suppression and overhaul that can hamper an investigation. In Unit I, your legal authority to be on scene, collect evidence, and conduct an investigation were covered, and these issues have many variables depending on your state laws, agency policies, and the particular agencies involved with the investigation. Make sure these bases are covered before the investigation begins. Examining the Fire Scene Once you are ready to begin the investigation, many investigators find value in locating witnesses early before they may leave the scene or have the opportunity to discuss what they bring to the investigation with others, possibly causing them to change or omit details of what they witnessed. These witnesses include occupants, neighbors, people who may have traveled by the incident, and firefighters who extinguished the fire. During this time, if the suppression efforts are ongoing, you will benefit from taking pictures or video of the fire. Once the fire is out, you may begin your scene examination. The number one thing to remember here is safety. Air monitoring should be done; all possible hazards should be identified and mitigated to the greatest extent possible before entering the incident site. Wearing a self-contained breathing apparatus (SCBA) or a filter mask are also considerations that the investigator should seriously consider depending on the environment of the incident. A 360-degree walk-around of the area involved should be completed; photographs should be taken; damage should be noted; and evidence should be collected, if found. Many investigators like using a voice recording device to help them record what they are seeing, and it can be recorded in writing at a later time. Once the exterior examination is complete, you will then move to the interior. Many investigators employ a pattern where they go from the least-damaged areas to the most-damaged areas. Others use a 360-degree approach on the interior as well, but whatever method serves you the best, you should follow it consistently. Notes or recordings should always be made, sketches or photos taken, and evidence collected and processed in a consistent manner. Noting the weather conditions when the fire started, the condition of the appliances and heating/cooling units, and the electrical service should be done on all fires, regardless of whether that information is pertinent to the cause of the fire. Fuels impact the way fire spreads, and the investigator must understand the different fuel types and how their state influences fire spread. Simplified, the three types of fuels (or states of matter) are gases, liquids (and their vapors), and solids. Fire investigators do not necessarily need to be chemists; however, becoming very familiar with the chemistry of fires and the fuels involved is crucial. The physical properties of fuels are covered in depth in Chapter 3 of your textbook. In particular, the textbook reminds us that fire investigators must be familiar with the following topics:

• heat of combustion,

• ignition energy,

• vapor density and pressure,

• flammability and explosive limits,

• ignition temperature,

• boiling points, and

• flash point/fire point. Fuel is the material that is burning or oxidizing in the combustion process. This material may also be referred to as the reducing agent. Most fuels are carbon-based and made up of hydrogen and oxygen. There are two main fuels to consider: hydrocarbon-based (e.g. gasoline, kerosene, and plastics) and cellulose-based (e.g. wood and paper). Liquid Fuels One essential fact to remember involving the combustion of liquid fuels is that the vapors of the fuel are what actually ignite—not the liquid itself. An additional fact to take into consideration is whether the liquid was on a nonporous or porous surface. Keep in mind that the evaporation rate on a porous surface will be considerably faster than that of a nonporous surface. Examples of what would be considered as nonporous surfaces are most plastics, metals, glass, and polyurethane- or varnish-coated wood; alternatively, carpet, cardboard, paper, and untreated woods are considered porous. One observation that can be made while examining a fire

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scene involving ignitable liquids is that burning may be at the edges of the pool of liquid, and the surface under the pool of liquid may be unburned because the liquid actually protects the surface. In addition, using a level, look at how the floor or surface lays or tilts to determine possible protected area were liquids might have traveled. Gaseous Fuels In discussing gases, an important fact to study is that gases have different gravities. In other words, some gases are heavier than air, and some are lighter than air. These specific gravities would come into play when examining a fire scene involving a flammable gas. For instance, both butane and propane are heavier than air, leading the investigator to observe low burn patterns (similar to gasoline); whereas, natural gas, which is lighter than air, would normally burn at a higher level. Solid Fuels Solid fuels are the most common fuel types that a fire investigator will examine. Solid fuels are more complex than liquids or gases. Wood, plastic, and paper have countless measurable properties in comparison to liquids or gases. Pyrolysis, or the decomposition of material brought on by heat, has to occur before sustained burning can take place within solid fuels, which is comparable to the vapors of a liquid burning. There are, of course, exceptions of non-pyrolysis fuels (e.g. reactive metals like magnesium, phosphorus, potassium, and sodium). Keep in mind that substances such as wood, coal, paint, and plastics do not actually burn. When heated, these substances decay or become pyrolytic in the form of particles (vapors) that are flammable; burning occurs as a result of these particles. That decay and the depth of char of a burnt structure, which can be visible on wall studs (see Figure 2.1) or ceiling joists, can convey a lot of information to the investigator. Not only can the depth of char indicate the movement of the fire, but it can possibly indicate the length of time that a fire burned.

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Sources of Ignition The items below must be considered by the fire investigator in order to make a determination regarding the ignition source that leads to the cause of a fire:

• ignition,

• competent ignition source,

• material first ignited, and

• ignition factor (cause).

Heat, which is a form of energy, is the primary source of ignition of every fire, and there are four different categories of heat energy: electrical, chemical, mechanical, and nuclear heat energy. The fire investigator is attempting to either rule out or rule in an ignition source using scientific methodology. Keep in mind that in order for a fire to start, an ignition source will need to be able to transfer enough energy to a fuel long enough to raise the fuel to its ignition temperature (National Fire Protection Association [NFPA], 2017b).

Figure 2.1: Fire pattern indicators found at fire scene (Icove & Haynes, 2018)

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After identifying the source of ignition, it is then critical to gather data in order to indicate what occurrence brought the source of ignition together with the fuel. This is known as the ignition sequence. Observable information, such as your personal observations of the area of origin, witness statements, or weather information, can all help substantiate your hypothesis as to the ignition sequence. Logically, the area of fire origin must be determined before the cause is determined. Interpreting fire patterns is a skill that must be learned by the investigator. By examining the fire patterns present, the fire investigator can determine the direction of the fire spread, location of combustibles or fuels, and sources of ventilation. How Fire Spreads Fire spreads by transferring the heat energy from the flames in three different ways.

• Conduction is the passage of heat energy through or within a material because of direct contact, such as a burning wastebasket heating a nearby couch, which ignites and heats the drapes hanging behind until they too burst into flames.

• Convection is the flow of fluid or gas from hot areas to cooler areas. The heated air is less dense and rises, while cooler air descends. A large fire in an open area produces a plume or a column of hot gas and smoke high into the air; however, inside a room, those rising gases encounter the ceiling. They travel horizontally along the ceiling, forming a thick layer of heated air, which then moves downward.

• Radiation is when heat is traveling via electromagnetic waves, without objects or gases carrying it along. Radiated heat goes out unnoticed in all directions until it strikes an object. Burning buildings can radiate heat to surrounding structures, sometimes even passing through glass windows and igniting objects inside (NFPA, 2017a).

Fire pattern indicators found at fire scenes can consist of the following components:

• demarcation,

• calcination,

• loss of material from wooden wainscoting and baseboards,

• fractured glass,

• ignitable liquid burn pattern on carpet,

• penetration into the ceiling, and

• area of clean burn where paper and pyrolysis products burned completely off the wall. Plumes, burn patterns, demarcations, beveling, surface effects, penetrations, and loss of material all must be analyzed and interpreted by the investigator to determine the cause and origin of a fire. Fire investigators should continue to develop their skills on what to look for when examining a fire scene and how to interpret what they observe.

References Icove, D. J., & Haynes, G. A. (2018). Kirk's fire investigation (8th ed.). Pearson. National Fire Protection Association. (2017a). Reporter’s guide: All about fire. http://www.nfpa.org/news-and-

research/news-and-media/press-room/reporters-guide-to-fire-and-nfpa/all-about-fire National Fire Protection Association. (2017b). NFPA 921: Guide for fire and explosion investigations.

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Suggested Reading The pages listed below from your textbook will provide you with more in-depth information about combustion of fuels and sources of ignition. Chapter 2: The Basic Science and Dynamics of Fire, pp. 69–128 Chapter 4: Sources of Ignition, pp. 236–285 In order to access the following resource, click the link below. The following article discusses the standard aspects for scientific-based investigations and analysis for incidents involving explosions and fires in the United States by the National Fire Protection and Control Administration. It addresses collecting evidence and important phases of failure analysis. It also outlines other factors for the preservation of documents, interviewing of witnesses, and v-burn patterns. Puckett, W., & Womack, R. (2016). Winning or losing a fire or explosion case: NFPA 921 investigations.

Claims 64(6), 22–23. https://libraryresources.columbiasouthern.edu/login?url=http://search.ebscohost.com/login.aspx?direc t=true&db=bth&AN=115880239&site=ehost-live&scope=site