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Fire investigation, sometimes referred to as origin and cause investigation, is the analysis of fire-related incidents. After firefighters extinguish a fire, an investigation is launched to determine the origin and cause of the fire or explosion. [1] These investigations can occur in two stages. The first stage is an investigation of the scene of the fire to establish its origin and cause. The second step is to conduct laboratory examination on the retrieved samples. [2] Investigations of such incidents require a systematic approach and knowledge of fire science.
The difficulty of determining whether arson has occurred arises because fire often destroys the key evidence of its origin. Many fires are caused by defective equipment, such as shorting of faulty electrical circuits. [3] [4] Car fires can be caused by faulty fuel lines, and spontaneous combustion is possible where organic wastes are stored. A fire investigator looks at the fire remains, and obtains information to reconstruct the sequence of events leading up to the fire. [5]
One of the challenging aspects of fire investigation is the multi-disciplinary basis of the investigator's job. As fires can be caused by or involve many ignition sources and fuels, an individual with expertise in fire chemistry should investigate the incident. [5] For example, if there is a gas appliance at the origin of the fire, an investigator should know enough about appliances to either include or exclude it as a possible cause of the fire. Fire investigators sometimes work with forensic engineers, such as forensic electrical engineers when examining electrical appliances, household wiring, etc.
In the United States, fire investigators often refer to NFPA 921: Guide for Fire and Explosion Investigations (National Fire Protection Association). Also, Kirk's Fire Investigation by David J. Icove and Gerald A. Haynes has long been regarded as the primary textbook in the field of fire investigation. [6] [7]
The main steps of a fire investigation include: [5] [8] [3] [9] [10]
Fire investigators conduct their investigations using a systematic approach utilizing the scientific method, including the following: [1] When arsonists attack, there is very rarely much evidence left at the scene. However, arsonists usually use accelerants to speed up a blaze. Forensic scientists use technologies to heat samples taken from the scene causing any residue to separate. This sample is then analyzed to determine the chemical structure. Scientists also use other tests such as using liquid nitrogen gas to trap residue which are then analyzed using gas chromatography. The investigator:
Depending on how much evidence is present, an investigator can use different approaches. Two techniques include process of elimination, or disregarding the causes that the evidence deems not possible. The second is to start investigating the most probable cause first until it is ruled unlikely. [3]
Fire scene reconstruction is critical to understanding complicated fires. When normal approaches fail, laboratory reconstructions become critical. They contribute to the resolution of critical issues and the enhancement of fire safety. A reconstruction's objective, whether it is a test, experiment, or demonstration, must be clearly stated. Various tests, ranging from small-scale to full-scale, help to understand fire behaviour. Clear agreements on size, safety, and data are required before proceeding. Specialist laboratories play an important role in increasing fire safety knowledge. [11]
Spoliation is the destruction or alteration of evidence through intention or ignorance. The mere act of extinguishing a fire can destroy potential evidence of arson or what is also known as an "incendiary fire." Firefighters are educated that the stream of their fire hose or the use of a pike pole can destroy evidence and efforts are made to do what is required to extinguish the fire, while not destroying clues to the fires' origin. [1] By taking steps before the investigation starts, destruction of evidence can be avoided. Investigators are encouraged to set barriers and secure the area. This allows for control to be taken over the crime scene and limits the chance of an investigation being compromised. Investigators then document any evidence seen at the crime scene or on the victims (clothes, burns, etc.) While looking for evidence, any findings that impose a threat to evidence, such as excessive use of fire-suppressing chemicals, unusual movement of handles/knobs, and changed position of evidence should be reported. [9]
Investigators can receive additional certification to prove their fire investigating skills. [12] The National Fire Protection Association (NFPA), through a document known as NFPA 1033, Standard for Professional Requirements for Fire Investigator, publishes minimum requirements for the knowledge skills and ability of a fire investigator. Principal among these is a 16-point list of areas in which a fire investigator is required to have education beyond high school level. The list mentions points such as using protective equipment, fire ignition, heat science, explosions, working with chemicals, investigating fires, using related technology, and reporting evidence. [1] These guidelines are recommended practice but are not required by law. [13]
Fire scene investigators may become certified through the National Association of Fire Investigators (NAFI) or the International Association of Arson Investigators (IAAI). Both certification programs rely heavily on the content of NFPA 1033 and NFPA 921. Both also require an application process detailing the investigator's education, training, and experience, and successfully challenging a written examination. Certificates are valid for a period of 5 years, at which time an investigator must demonstrate continued participation in the field and a minimum amount of continuing education in order to be recertified.
The National Association of Fire Investigators (NAFI), a professional association of fire and explosion investigators, offer several National Board Certified fire investigation certifications including:
The International Association of Arson Investigators (IAAI), a professional group of fire investigators, grants the following certifications:
A firewall is a fire-resistant barrier used to prevent the spread of fire. Firewalls are built between or through buildings, structures, or electrical substation transformers, or within an aircraft or vehicle.
Forensic engineering has been defined as "the investigation of failures—ranging from serviceability to catastrophic—which may lead to legal activity, including both civil and criminal". The forensic engineering field is very broad in terms of the many disciplines that it covers, investigations that use forensic engineering are case of environmental damages to structures, system failures of machines, explosions, electrical, fire point of origin, vehicle failures and many more.
The National Institute of Justice (NIJ) is the research, development, and evaluation agency of the United States Department of Justice (DOJ).
A fire marshal, in the United States and Canada, is often a member of a state, provincial or territorial government, but may be part of a building department or a separate department altogether. Fire marshals' duties vary but usually include fire code enforcement or investigating fires for origin and cause. Fire marshals may be sworn law enforcement officers and are often experienced firefighters. In larger cities with substantially developed fire departments the local fire departments are sometimes delegated some of the duties of the fire marshal.
Electrical wiring in North America follows the regulations and standards applicable at the installation location. It is also designed to provide proper function, and is also influenced by history and traditions of the location installation.
The National Electrical Code (NEC), or NFPA 70, is a regionally adoptable standard for the safe installation of electrical wiring and equipment in the United States. It is part of the National Fire Code series published by the National Fire Protection Association (NFPA), a private trade association. Despite the use of the term "national," it is not a federal law. It is typically adopted by states and municipalities in an effort to standardize their enforcement of safe electrical practices. In some cases, the NEC is amended, altered and may even be rejected in lieu of regional regulations as voted on by local governing bodies.
Fire safety is the set of practices intended to reduce destruction caused by fire. Fire safety measures include those that are intended to prevent the ignition of an uncontrolled fire and those that are used to limit the spread and impact of a fire.
In electrical and safety engineering, hazardous locations are places where fire or explosion hazards may exist. Sources of such hazards include gases, vapors, dust, fibers, and flyings, which are combustible or flammable. Electrical equipment installed in such locations can provide an ignition source, due to electrical arcing, or high temperatures. Standards and regulations exist to identify such locations, classify the hazards, and design equipment for safe use in such locations.
NFPA 70E(Standard for Electrical Safety in the Workplace) is a standard of the National Fire Protection Association (NFPA). The document covers electrical safety requirements for employees. The NFPA is best known for publishing the National Electrical Code.
Active fire protection (AFP) is an integral part of fire protection. AFP is characterized by items and/or systems, which require a certain amount of motion and response in order to work, contrary to passive fire protection.
A fire alarm system is a building system designed to detect, alert occupants, and alert emergency forces of the presence of fire, smoke, carbon monoxide, or other fire-related emergencies. Fire alarm systems are required in most commercial buildings. They may include smoke detectors, heat detectors, and manual fire alarm activation devices. All components of a fire alarm system are connected to a fire alarm control panel. Fire alarm control panels are usually found in an electrical or panel room. Fire alarm systems generally use visual and audio signalization to warn the occupants of the building. Some fire alarm systems may also disable elevators, which are unsafe to use during a fire under most circumstances.
Arc mapping is a technique used in fire investigation that relies on finding the locations of electrical arcs and other electrical faults that occurred during a fire; the locations of the electrical faults can then, under some circumstances, indicate the progression of the fire over time. It is usually performed by a forensic electrical engineer. It The technique relies on the assumption that, when heat from fire impinges on an electrical line, it will melt the wire insulation and cause an electrical fault at the first point that it reaches on the electrical line. For this to occur, the electrical line must be energized at the time that fire hits it.
Forensic electrical engineering is a branch of forensic engineering, and is concerned with investigating electrical failures and accidents in a legal context. Many forensic electrical engineering investigations apply to fires suspected to be caused by electrical failures. Forensic electrical engineers are most commonly retained by insurance companies or attorneys representing insurance companies, or by manufacturers or contractors defending themselves against subrogation by insurance companies. Other areas of investigation include accident investigation involving electrocution, and intellectual property disputes such as patent actions. Additionally, since electrical fires are most often cited as the cause for "suspect" fires an electrical engineer is often employed to evaluate the electrical equipment and systems to determine whether the cause of the fire was electrical in nature.
NFPA 921, "Guide for Fire and Explosion Investigations", is a peer reviewed document that is published by the National Fire Protection Association (NFPA). Its purpose is "to establish guidelines and recommendations for the safe and systematic investigation or analysis of fire and explosion incidents". Familiarity with NFPA 921 is strongly recommended by National Association of Fire Investigators and the International Association of Arson Investigators (IAAI). NFPA 921 forms a large basis of the information which a professional fire investigator must know to pass the various Fire Investigator Certification examinations.
Kirk's Fire Investigation by David J. Icove and Gerald A. Haynes has long been regarded as the primary textbook in the field of fire investigation. It is currently in its 8th edition.
The National Association of Fire Investigators (NAFI) is a professional association of people who investigate cases of fire and arson. It was created in 1961 and is located in Bradenton, Florida. The purpose of the group is to increase knowledge and improve skills of fire investigators in the field and in relation to the litigation involved in determining the origin and cause of fires.
The following outline is provided as an overview of and topical guide to forensic science:
A combustible material is a material that can burn in air under certain conditions. A material is flammable if it ignites easily at ambient temperatures. In other words, a combustible material ignites with some effort and a flammable material catches fire immediately on exposure to flame.
David J. Icove is a former Federal Bureau of Investigation Criminal Profiler and FBI Academy Instructor in the elite Behavioral Analysis Unit. He was one of the FBI's first criminal profilers to specialize in the apprehension of serial arsonists and bombers. He is a Fellow of the National Academy of Forensic Engineers and co-author, along with Gerald A. Haynes, of Kirk's Fire Investigation, the leading textbook in the field of fire investigation.
Detection of fire accelerants is the process that a fire investigator uses to determine if fire accelerants were used at a fire scene. This process involves a combination of both field work and laboratory analysis by fire investigators and chemists.