Lect 2 Fire Investigation

Fire

The rapid oxidation of a material in the exothermic chemical process of combustion, releasing heat, light, and various reaction products.

Arson

The crime of intentionally and maliciously setting fire to buildings, wildland areas, vehicles or other property with the intent to cause damage.

Combustion

The process of burning a material, resulting in the release of heat, light, and reaction products.

Exothermic

A chemical reaction that releases heat to its surroundings.

Accelerants

Substances used to increase the speed or intensity of a fire.

Ignition sources

Objects or substances that can start a fire.

Detonation devices

Devices used to cause an explosion.

Wildfires

Uncontrolled fires that occur in natural areas, such as forests or grasslands.

Spontaneous combustion

The ignition of a material without an external heat source, often due to chemical reactions within the material.

Insurance compensation

Financial reimbursement provided by an insurance company for damages caused by a fire.

Terrorism

The use of violence and intimidation in pursuit of political, religious, or ideological goals.

Incident Command

The designated individual or group responsible for managing and coordinating emergency response efforts at a fire scene.

Safety gear

Protective clothing and equipment worn by firefighters to ensure their safety during firefighting operations.

NFPA 1977

National Fire Protection Association standard for protective clothing and equipment for wildland firefighting.

NFPA 1500

National Fire Protection Association standard for fire department occupational safety and health programs.

OSHA

Occupational Safety and Health Administration, a federal agency that sets and enforces workplace safety standards.

Personal Protective Clothing

Clothing and equipment worn by firefighters to protect themselves from the hazards of firefighting.

Working Hypothesis

A tentative explanation or theory based on available evidence and subject to further testing and refinement.

Scientific Method

A systematic approach used to investigate and understand natural phenomena, involving observation, hypothesis formulation, data collection, analysis, and conclusion.

Deductive Reasoning

A logical process of reasoning that starts with general principles or premises and applies them to specific situations to reach a conclusion.

Inductive Reasoning

A logical process of reasoning that starts with specific observations or data and uses them to form general principles or hypotheses.

Fire Pattern

The visible evidence left behind by a fire, such as burn marks, charring, and smoke patterns, that can provide clues about the fire's origin and behavior.

Point of Origin

The specific location within a fire scene where the fire started.

Fuel

Any material that can undergo combustion and provide energy for a fire.

Oxygen

A gas necessary for combustion to occur.

Fire Dynamics

The study of how fires start, spread, and behave.

Loss Histories

Records or documentation of previous fire incidents that can provide insights into fire patterns, causes, and behavior.

Witness Statements

Testimonies given by individuals who observed the fire or were present at the scene, providing valuable information for the investigation.

Exterior Examination

The process of inspecting the exterior of a fire scene for any evidence or clues related to the fire's origin or cause.

Interior Examination

The process of inspecting the interior of a fire scene to gather evidence and determine the path and behavior of the fire.

Charring

The blackened appearance of material that has been burned, often used to assess the severity and extent of fire damage.

V-patterns

Visible patterns in the shape of a "V" formed by the direction and intensity of heat and flames during a fire, which can indicate the area or point of origin.

Lightbulbs

Objects that can provide evidence of fire direction and intensity based on their condition and damage.

Window panes

Glass panels in windows that can provide clues about the fire's origin and behavior based on their condition and damage.

Floor Damage

Floors are usually damaged less than ceilings in a fire, and floor damage can indicate the area of origin.

Spalling

Chipping or breaking away of concrete, which can indicate high temperatures and the use of fire accelerants.

Arson

The three basic elements of arson are the burning of property, incendiary origin, and intent to destroy.

Motives for Arson

Motives for arson include profit or fraud, vandalism and thrill-seeking, excitement and thrill-seeking, revenge or retaliation, crime concealment, and extremism or terrorism.

Indications of Arson

Signs of arson include multiple points of origin, evidence of incendiary devices, signs of ignitable liquids, low levels of charring, and hourglass and inverted V-patterns.

Multiple Points of Origin

Arsonists may set multiple fires to maximize damage.

Signs of Incendiary Devices

Evidence of incendiary devices can include metal parts of electrical devices such as timers, lighters, or staples from matchbooks found in fire debris.

Signs of Ignitable Liquids

Ignitable liquids will flow to the lowest point and can soak into materials, producing pronounced damage to the floor area.

Low Levels of Charring and Patterns

Low levels of charring may indicate the presence of ignitable liquids, and patterns such as inverted V or hourglass can also indicate the use of ignitable liquids.

Fire-related Deaths

Questions related to fire-related deaths include identifying the remains, determining the cause and manner of death, and evaluating if the death was due to the fire.

Self-extinguishing Cigarette

Safer cigarettes that have lowered permeability bands to slow down the rate of burning.

General Fire Evidence

Laboratory analysis of charred or burned materials to identify their nature and extent of damage.

Laboratory Analysis of Burned Documents

Examination of burned documents using visible, UV, or IR light to improve contrast between ink and paper.

Proving Arson

There is no definitive test for arson, but clues such as accelerant traces and patterns of behavior can help identify arsonists.

Laboratory Analysis of Appliances and Wiring

Microscopic examination and elemental analysis can provide evidence of shorting or damage in the fire.

Furnishing and Appliances

Furniture and appliances may show signs of intense burning on the underside if accelerants were used on the floor.

Collecting and Preserving Arson Evidence

It is important to begin the investigation as soon as the fire is extinguished and to document the crime scene before salvage operations and cleanup procedures begin.

Ash and Debris

Absorbent materials such as wood, paper, fabric, and carpeting that can retain traces of accelerant.

Collection Containers

Clean and airtight containers used to collect ash and debris, such as clean lined or unlined quart or 1-gallon-size paint cans or glass jars with screw-top lids.

Polyethylene or Kapak Bags

Suitable bags for collecting ash and debris, as paper and nylon bags should not be used.

Liquid Samples

Samples of liquids, including the contents of cans that may have been used to transport accelerant, should be sampled into small Teflon-lined glass vials.

Unburned Materials

Items such as floorings, rugs, pillows, cushions, furniture, rubbish, clothing, and rags that should be sampled into properly labeled airtight containers.

Substrate Control

The process of collecting evidence from areas in the room far away from the origin to establish an exemplar of the normal conditions of a room.

Accelerant Recovery

Methods for recovering traces of accelerant from fire debris samples, including direct headspace, static headspace, dynamic headspace, solvent extraction, and steam distillation.

Laboratory Analysis

Analysis for the presence of accelerants in suspect samples, often using gas chromatography coupled to a mass spectrometer.

Classification of Arson Accelerants

A classification system for different types of accelerants based on their boiling points, including light petroleum, gasolines, medium, kerosene, heavy, and unclassified accelerants.

Origin Determination

The process of finding the origin of a fire, often marked by intense burning at a low point, and the need to sample a larger area than initially thought.

UV Light Source

A tool used to detect suspicious circumstances near the origin of a fire, such as small fires in several areas, the use of devices to spread fire, and ignition in unusual places.

Mass Spectrometry

A technique used to determine the molecular weight and formula of a compound by vaporizing and ionizing the compound with a beam of high-energy electrons.

Mass spectrometer

A device used to analyze the mass-to-charge ratio of ions in a sample.

Mass spectrum

A plot that shows the intensity of each ion versus its mass-to-charge ratio.

M + 1 peak

The peak in a mass spectrum that corresponds to ions with a slightly higher mass due to the presence of isotopes.

Spectroscopy

The measurement of the interaction between a compound and electromagnetic radiation of different wavelengths.

Nuclear Magnetic Resonance Spectroscopy (NMR)

A spectroscopic technique that measures the absorption of radio waves by carbon and hydrogen atoms in a magnetic field.

Infrared (IR) Spectroscopy

A spectroscopic technique that measures the absorption of infrared radiation by organic compounds.

Ultraviolet/Visible Spectroscopy (UV/Vis)

A spectroscopic technique that measures the absorption of ultraviolet and visible light by pi bonds in an organic compound.

Derivative spectroscopy

A technique that uses the derivatives of absorbance with respect to wavelength for qualitative analysis and quantification.

First-order derivative

The rate of change of absorbance with respect to wavelength.

Second-order derivative

The second derivative of absorbance with respect to wavelength.

Fire origin

The location where a fire starts.

Garley Building

A building in Hong Kong where a fire occurred.

Bunsen burner

A device used for heating in laboratories, with an air hole that allows for controlled combustion.

Ignition

The process of starting a fire.

Sprinkler system

A system that uses water to extinguish or control fires.

One Meridian Plaza

A building located in Philadelphia where a fire occurred.

Eye witness reports

Accounts given by individuals who saw the fire at One Meridian Plaza.

Frame by frame viewing

A method used by investigators to analyze video footage by examining each individual frame.

Renovation work

The process of making improvements or repairs to a building.

Hard wood

A type of wood that is dense and durable.

Internal investigation

An inquiry conducted within an organization to gather information and determine the cause of an incident.

Residue

The remaining material or substance left after a fire or other event.

Hinges

The movable joints that allow a door to swing open and closed.