Fire Investigation and Evidence Preservation - Coursework Example

Fire Investigation and Evidence Preservation 1. Introduction The basic objectives of any quality fire scene investigation is to establish and document the origin and cause of the fire and learn what human actions or failures contributed to ignition and fire development. However, in an extensively fire-damaged building this can be a complicated undertaking considering the danger of collapse and other hazards that will confront the investigator. Sound judgement, tenacity, endurance, good observation skills and memory, well-developed technical skills and substantial experience interpreting fire damage patterns are essential qualification for a fire investigator. The focus of this research is to recognize the signs, symptoms and causes of collapse. It will also include hazards that may encounter during the investigation and proper approach to information gathering and evidence preservation. Finally, it will explore the various indicators of arson and prevention methods that property owners can apply. 2. Fire Investigation Fire investigation involves examination of the fire scene to determine the cause, origin, development of fire, and laboratory analysis of samples recovered from a fire scene. Fire investigator should have an understanding of a variety of concepts such as the basic practices and methodology, and frequently used materials in buildings and their effect on and reaction to fire development, and the required setting for a fire to be started and sustained (Redsicker and O’Connor 1996, p.29). Investigators should be aware of burn and smoke patterns, their interpretation, and various types of fuel package, their auto-ignition temperatures, behaviour in fires and the level of heat release, which they may produce. Importantly, they are knowledgeable of sampling protocols, packaging and related activities (Daeid 2004, p.4). 2.1 Signs and Symptoms of Collapse Building failures that can be observed on the fire scene include smoke or water through walls, soft floors, small partial collapse, and unaligned walls. Intrinsic structural instability of a building aggravated by fire is a common sign of likely collapse. Another is the non-masonry supporting elements’ failure where parts of a building masonry depend. Retained water added to live load because of fire fighting operations. The disintegration of masonry wall because of intense heat and the collapse of another building into the structure under investigation (Brannigan 1992, p.156). Normally, building elements and materials show signs of potential collapse. For instance, poorly made bricks absorb moisture and can deteriorate because of freezing. Brick defects and unaligned masonry, deteriorated parapet walls, water-soluble sand lime mortars are probable failure hazard. Wooden beams bear massive weight thus deterioration of the wood in a fire trigger the collapse of the supported masonry structure (Brannigan 1992, p.157). Cracks signify weak spot in the wall, which may be due to poor foundations. As a result, when one part of the wall pushed, the rest of the wall collapses. An indicator of a wall being pushed out by steel roof beams is a horizontal crack getting longer particularly during the hot season. Consequently, they contract in winter resulting to unaligned walls. A brick or stone may fell out of an arch thus reducing the stability of the arch. Burned out window or doorframe supporting masonry may collapse due to stress (Brannigan 1992, p.157). It is vital to check the wall joints since walls are normally made of various materials, such as brick and stone that expands and shrink at various rates. Large holes cut through walls for lintel installation makes wall considerably weaker and probably collapse. Another basic sign of a wall in distress are braced walls, which can be very dangerous after a fire. The bottom concrete of a reinforced-concrete lintel in masonry walls may spall off exposing the rods that provide tensile strength to the combined structure causing the lintel to collapse. More importantly, gas such as carbon monoxide trapped in unventilated voids can ignite violently and explode (Brannigan 1992, p.158). 2.2 Hazards at Fire Scene Investigation Working in and around fire scenes can be intrinsically hazardous thus investigator should check the exterior of the structure to assess probable danger. According to Almirall et. al. (2006, p.39), investigators should carefully check unsupported or inadequately supported building components such as wall, floors, roofs, and stairways that may have the probability for collapse. The spot and status of all utilities such as gas, water, electricity and the presence of hazardous material should be evaluated. Airborne contaminants are considered one of the greatest safety hazards at a fire scene. While conducting a fire investigation, investigators are repeatedly exposed to respiratory hazards, as synthetic materials are common in households and commercial products. For instance, products containing plastics, foams, insulation, paints, and fibres are virtually at all times present in a typical structure fire. These materials can release gases, vapours, aerosols, fibres, and particles thus hazardous to humans. More importantly, carbon monoxide, hydrogen cyanide, oxides of nitrogen, and aldehydes are usually found in a fire scene and exposure to these contaminants can result in both severe and unremitting deadly effects. Electrical activity, pooled water, confined spaces, biological hazards, and low lighting conditions are all considered health and safety issues at the fire scene (Almirall et. al. (2006, p.40). One of the principal safety issues at the fire scene is the public utility service to a structure. Fire departments will usually secure the electrical service to a residential or light commercial structure by disconnecting the electric meter. Gas service is simply restrained by the shutting down the valves at the gas meter. When carrying out an investigation in a basement or on a concrete slab, a shallow pool of water may in reality a deep sump pit or another hole in the floor. Biohazards such a sewage, infectious waste, etc may be contain in the water particularly in building previously occupied by homeless persons or have been used for criminal activities (Almirall et. al. (2006, p.40). 2.3 Information Gathering and Preservation A safe and successful fire scene examination is being carried out in a rational and methodical way in accordance with established practices. The primary objectives of well-planned fire scene investigation are to establish the source of the fire, the cause of the fire, locate, document, and preserve evidence significant to the cause of the fire or related criminal acts. Fire scene investigations normally involve three broad areas; witness interviews, physical examination, and forensic or engineering analysis (Almirall 2006, p.46). Witness interviews are conducted as part of a wide-ranging fire investigation. It is a vital source of information in determining the cause and origin of many fires (Ward 2005, p.345). Fire investigators need the information from witnesses, as these would help them pinpoint the cause of fire. As a good practice, the investigator accompanies the witness back to the fire scene and cross-examines at the location where the observations were made. Investigator should guide them through their description of the events, as it would help clarify perception of what a witness saw and sense any irrelevant and doubtful information surrounding the investigation (Almirall 2006, p.46). The following questions Almirall (2006, p. 47) suggested are useful in acquiring information regarding the fire. The witness must be questioned on how they learnt about the fire. Who else was with them at the time they have seen the fire? What they did after they learned about the fire? What they have witnessed and where was the fire located in the structure? Let the witness described the fire and smoke or anything they hear or smell. Did they photograph or video tape the fire? Let them describe the condition of doors or windows, breakage and anything unusual. Ask the witness about activities around the structure such as presence of any person, vehicle, and other activities before or during the fire. Preserving evidence is essential to any fire investigation thus; fire investigator should have a plan for collecting evidence. For instance, samples least likely to contain residues should be collected first for samples intended for ignitable liquid residue analysis, as this would minimize the risk of cross-contamination. Label the evidence containers with the following information: Unique case number of file number identifying the fire scene, sample’s serial number, description of the substrate material, location of the sample, date collected, and initials of the investigator collecting the sample. The labelled containers, cans, plastic, or glass, should be placed at the site where the sample will be collected, and photographed in place before the sample is placed in the can. The location of the sample is the single most significant characteristic of the sample, so it is vital that this information be carefully documented. When gathering sample for ignitable liquid residue analysis, the investigator should put on disposable latex gloves, and replace gloves between each sample. The location of any sample collected should be noted on the investigator’s sketch and an evidence transmittal form should be accomplished as soon as conveniently possible after collecting the samples. Finally, samples should not be kept longer than necessary prior to submission to the laboratory (Lentini 2006, p.116). 2.4 Indicators of Arson and Prevention “Arson is unlawful intentional fire setting without permission of the owner of a property (Arrington 2006, p. 69)”. Included in a fire investigation is determining the origin, cause, and possible commission of a crime. As fire investigation gets deeper into the fire scene, investigators may be confronted with existing evidence of arson and other crimes. According to Redsicker (2000, p.51), possible indicators of arson or other crimes are as follows. Vehicles and individuals leaving the scene, exterior doors removed or opened, windows open or broken, windows shades down, windows covered, signs of forcible entry, jimmy marks, locks removed from windows, or doors, holes cut in walls, separate and unconnected fires. Other indicators may include colour of smoke and flame (see table below) , indications of accelerants, incendiary devices, trailers, deliberately created short circuit, disconnected or loosened oil or gas line, footprints, pets and items of monetary or sentimental value removed from premises, inoperative alarm systems, fire doors, sprinkler systems, and blood stains or splatters. Smoke and Flame Colour Source: Redsicker (2000) Smoke Flame Possible Combustible White to gray Yellow to white Benzene Gray to brown Yellow to red Wood, paper, cloth Brown Yellow Cooking oil Brownish black Yellow to read Lacquer thinner Black to brown Yellow to white Turpentine Brown to black Straw to white Naphtha Black Yellow to white Lubricating oil, Gasoline Black Yellow Kerosene Black Blue Acetone “Accelerants are agents, often an ignitable liquid, used to initiate a fire or increase the rate of fire growth” (Ward 2005, p.350). There are certain visual signs of arson that exposed the consequence on materials of heating or partial burning, which are utilized to point out different characteristic of a fire such as rate of development, temperature, duration, time of occurrence, presence of flammable liquids, and points of origin. The interpretation of burn indicators is the primary method of determining the causes of fires. Understanding burn patterns helps in establishing arson. Alligator effect is the checkering of burnt wood and large progressing blisters suggest rapid intense heat while small flat alligator marks indicate long low heat. Crazing glass is also an indicator of rapid and intense heat and suggests potential fire accelerant. The depth of burn is used to establish the extent of burn to trace the point of origin of the fire. The line of demarcation between burnt and unburned material suggest fire accelerant and intense fire. A fire originating inside the cushions or an external fire intensified by fire accelerant can result in sagged furniture springs. Lastly, spalling surface of concrete, cement, or brick caused by intense heat also indicate the use a fire accelerant (Fay 2007, p.127). Fire departments fire prevention program highlights that the property owner can do his or he part to thwart arson. Arrington (2006, p.70) recommend the following: The owner must handle flammable material safely, dispose garbage, leaves, wood, and other flammable items appropriately, report any smoke or fires, consider installing an audible fire and smoke alarm system, smoke detectors , keep matches and lighters out of reach of young children. They must also develop and practice a home fire escape plan, keep emergency numbers handy, do not let clutter blocked exits , and report any suspicious individual or activities that they may noticed. On average, arsonist as other criminals want to start fires in spots that are concealed thus enhancing surveillance in these places by the lighting the area and eliminating visual barriers to natural observation helps. It is almost impractical for an arsonist to start a fire in detectable locations and fires in such places are easily detected and suppressed (Arrington 2006, p.70). 3. Conclusion Fire investigation is to determine the cause, origin, development of fire, and laboratory analysis. Investigators should be familiar with various concepts and practices involve in a fire scene and crime scene investigation. In a building fire, investigator must have a fundamental understanding of commonly used materials and their effect on and reaction to fire spread. Indicators of building failure that may be observed on the fire ground include smoke or water through walls, failure of masonry supporting elements, etc. Signs of potential collapse can be poor bricks, unaligned masonry, cracks and holes in the wall, braced walls, and so forth. Working in and around the fire scene is dangerous thus investigator must be aware of potential hazards such as non-supported building components, utilities like gas, water, electricity, levels of oxygen, carbon monoxide, and airborne contaminants. Witness interview is a significant source of information that could help in determining the cause and origin of a fire and proper samples collection and evidence preservation are vital to the success of any fire scene investigation. 4. Reference List Almirall José, Furton Kenneth, Almirall R., 2004, Analysis and Interpretation of Fire Scene Evidence, Published by CRC Press, U.K. Arrington Rick, 2006, Crime Prevention: The Law Enforcement Officer's Practical Guide, Published by Jones & Bartlett Publishers, U.S. Daeid Niamh Nic, 2004, Fire Investigation, Published by CRC Press, U.K. Brannigan Francis, 1992, Building Construction for the Fire Service, Published by Jones & Bartlett Publishers, U.S. Fay John, 2007, Encyclopedia of Security Management, Published by Butterworth-Heinemann, U.K. Lentini John, 2006, Scientific Protocols for Fire Investigation, Published by CRC Press, U.S. Redsicker David, 2000, The Practical Methodology of Forensic Photography, Published by CRC Press, U.K. Redsicker David and O'Connor John, 1996. Practical Fire and Arson Investigation: Second Edition, Published by CRC Press, U.S. Ward Michael, 2005, Fire Officer: Principles and Practice, International Association of Fire Chiefs, National Fire Protection Association, Published by Jones & Bartlett Publishers, U.S. Read More