IAFC Fire officer principles practice 3Ed ch 18 Fire cause determination ID: 776735
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Slide1
Chapter 18
Fire Cause Determination
Slide2Fire Officer I
Objectives
Identify the common causes of fire. Explain when to request a fire investigator. Describe how to find the point of origin of a fire. Discuss the legal considerations of fire cause determination.
Slide3Fire Officer II
Objectives
Discuss the nature of fire investigation. Describe how to find the point of origin of a fire.Describe how to determine the cause of the fire.Describe the fire cause classifications.
Slide4Fire Officer II
Objectives
Describe the indicators of incendiary fire.Discuss arson.Describe the documents and reports a fire officer must complete.
Slide5Fire Officer II
Objectives
Describe how a fire investigation continues after fire official involvement has ended.
Slide6Introduction
An investigation is conducted to determine how a fire started.
Understanding the cause:Helps prevent future firesHelps determine if criminal acts were involved
Slide7Introduction
The incident commander is responsible for conducting the investigation.
The legal responsibility for conducting the investigation is defined by state or local legislation or regulations.
Slide8Common Causes of Fires
A relatively small number of causes are responsible for a large number of fires.
Slide9Requesting an Investigator
The fire officer should determine the point of origin and probable cause.
On small or routine incidents, this is the only investigation conducted.
Slide10Requesting an Investigator
A set of guidelines explains when to request an investigator:
Death or serious burn injuryDeliberate fireLarge-loss firePossible crime
© Stud Milne/AP Images
Slide11Fire Growth and Development
To determine the fire’s point of origin, the fire officer must understand fire behavior, growth, and development.
Three methods of heat transfer:ConductionConvectionRadiation
Slide12Disabled Built-in Fire Protection
May be encountered in fires involving industrial or commercial occupancies
Look for damage or vandalism:Sprinkler hook-upsHose cabinetsHard-wired smoke detectorsHigh-rise communication systems
Slide13Delayed Notification or Difficulty Getting to the Fire
Be alert for conditions that delay the fire department’s ability to get to the fire:
Malfunctioning keys or key cardsVandalized doorsMaterials blocking accessPoints of origin in the attic, the basement, or a closet
Slide14Tampered
or Altered Equipment
Document unusual conditions:Indications of forcible entryAltered electrical devicesUse of excessive fuel
Slide15Legal Considerations
The fire officer who investigated the fire may be called to testify in court.
May be challenged on issues of proper procedure
Slide16Searches
Typically no search warrant is needed to enter the fire scene, collect evidence, and determine the cause of a fire.
A warrant is required after fire origin and cause have been determined:Administrative search warrantCriminal search warrant
Slide17Securing the Scene
If the fire officer suspects a crime has occurred:
Immediately request a fire investigator.Secure the scene and maintain custody until the investigator arrives.
Slide18Evidence
Evidence: material objects and statements that are admissible as testimony in a court of law
Demonstrative evidenceDocumentary evidenceTestimonial evidence
Slide19Evidence
Artifacts could include:
Remains of the material first ignitedRemains of the ignition sourceAn item on which fire patterns are present
Slide20Evidence Must Be Protected
The investigator’s goal is to identify the point of origin and the cause of the fire.
Fire scene reconstruction: re-creating the physical scene before the fire occurred, either physically or theoretically
Slide21Evidence Must Be Protected
The investigator must locate, examine, and preserve evidence.
The fire officer must determine when to stop firefighting operations as part of this effort.
© Glen E.
Ellman
Slide22The Nature of Fire Investigation
Fire investigation involves skill, technology, knowledge, and science.
Factual data must be compiled and analyzed.Investigations must be systematic.The origin must be determined before the cause is settled.
Slide23Finding the Point of Origin
Point of origin: exact location where a heat source and fuel came in contact
The fire investigator usually starts in the area where the least amount of damage occurred.
Slide24Finding the Point of Origin
To find the point of origin, the investigator analyzes:
Fire patterns left by the fireObservations of witnessesThe physics and chemistry of fire initiation, development, and growth
Any location and circuit where electrical arcing has caused damage
Slide25Fire Patterns
The point of origin can often be identified by fire patterns.
Movement pattern: V- or U-shaped patternIntensity pattern: response of materials to the rate of heat release and flux
Courtesy of Eddie D. Smith/Unified Investigations & Sciences, Inc.
Slide26Fire Patterns
Char: blackened remains of carbon-based material after it burns
Helps determine:Direction of fire spreadApparent duration and intensity
© Vladimir
Zanadvorov
/
ShutterStock
, Inc.
Slide27Determining the Cause
of the Fire
Cause: circumstances and factors that were necessary for the fire to occurDetermine the source of ignition.Determine the fuel that was first ignited.Determine the circumstances or human actions that allowed the ignition source and fuel to come together.
Slide28Source and Form of
Heat Ignition
Source of ignition: energy source that caused the material to igniteA competent ignition source has three properties: GenerationTransmissionHeating
Slide29Material First Ignited
Type of material: nature of the material
Form of material: how the material was used
Slide30Ignition Factor or Cause
Could be a human act
Could be related to: Mechanical failurePoor or improper assembly of a deviceWorn-out piece of equipmentNatural force
Slide31Ignition Factor or Cause
Failure analysis: logical, systematic examination of an item, component, assembly, or structure
Identifies the probability, causes, and consequences of potential and real failures
Slide32Fire Analysis
Scientific process of examining a fire occurrence to determine relevant facts:
OriginCauseSubsequent developmentResponsibility for whatever occurred
Slide33Fire Analysis
The fire officer may need to construct a timeline of events.
Reproduced with permission from NFPA 921, Guide for Fire and Explosion Investigations, Copyright © 2008, National Fire Protection Association. This reprinted material is not the complete and official position of the NFPA on the referenced subject, which is represented only by the standard in its entirety.
Slide34Conducting Interviews
Interview victims, witnesses, fire fighters, and suspected perpetrators.
Conduct separate interviews.Use open-ended questions.Conduct interviews at the fire scene.Document interview information.
Slide35Vehicle Fire Cause Determination
Determine the fire’s point of origin.
Determine the cause.Look for indications of arson.
Slide36Vehicle Fire Cause Determination
Consider sources of accidental ignition.
Note the make, model, and year of the vehicle, and the VIN. Interview the driver(s).
©
AlexKalashnikov
/
ShutterStock
, Inc.
Slide37Wildland Fire Cause Determination
The amount and cost of wildland fire suppression efforts are increasing.
Different characteristics from structure fires:Influenced by environmental conditionsSpread vertically through convection and horizontally through radiation
Slide38Wildland Fire Cause Determination
Factors affecting the rate of spread:
Type and density of material burning Wind speed and directionHumidity and fuel moisture content
Slope of the terrain and natural features
©
AbleStock
Slide39Wildland Fire Cause Evidence
Campfire remains
Time-delay devicesCigarette remainsLightersMultiple ignition pointsSplintered trees
Fulgurites
Barrels used to burn trash
Fallen wires
Trees on power lines
Railroad tracks
Slide40Fire Cause Classifications
Accidental
NaturalIncendiaryUndetermined
Slide41Accidental Fire Causes
Leading causes of residential fires:
Unattended cookingSmoking materialsHeating
Courtesy of the NJ State Fire Marshal’s Office, Arson/K-9 Unit.
Slide42Accidental Fire Causes
Pyrolysis lowers ignition temperature
.Consider it if the area of origin includes steam pipes, fluorescent light ballasts, flue pipes for a fireplace, or a wood-burning stove.The most common electrical fire scenario is misuse by the occupant.
Slide43Natural Fire Causes
Lightning
EarthquakesTornadoes
Floods
Hurricanes
Volcanoes
Slide44Incendiary Fire Causes
Intentionally started fires
Not necessarily arsonThe fire officer may help determine the fire’s cause and origin and classify it as incendiary.The prosecutor or grand jury decides whether it is arson.
Slide45Undetermined Fire Causes
Sometimes the cause of a fire cannot be determined.
Damage too extensiveMultiple causes can’t be ruled outNot enough evidence or absence of any logical cause
Slide46Indicators of Incendiary Fires
Eliminate accidental and natural causes
Conditions indicating intentional fire:Disabled built-in fire protectionDelayed notification/difficulty getting to fireAccelerants and trailersMultiple points of originTampered or altered equipment
Slide47Accelerants and Trailers
Accelerants: agents used to initiate a fire or increase the rate of fire growth
Courtesy of Robert A. Corry/
SceneInvestigator.com
Slide48Accelerants and Trailers
Trailers: materials used to spread a fire from one area of a structure to another
Paper towelsGasoline or other flammable liquidsDecorative streamersNewspapers
Slide49Multiple Points of Origin
Arsonists setting multiple ignition points
Materials falling from the ceiling and creating a secondary “U” or “V” patternElectrical surge causing ignition points at different locations
Slide50Arson
Crime of maliciously and intentionally or recklessly starting a fire
Highest rate of juvenile involvement compared with other serious felonies
Slide51Arson
Motives
ProfitTo collect insurance moneyTo facilitate extortion To eliminate competition
Crime concealment
To destroy embezzlement records
To destroy evidence of other crimes
To distract responders while a crime is taking place
Slide52Arson
Motives
ExcitementTo seek thrills, attention, or recognitionSpite/revengeTo express hatred or jealousy
Extremism
To cause a monetary loss to a business
To bring attention to a cause
Vandalism
To cause damage for its own sake
Slide53Documentation and Reports
All fires must be documented and reported according to the fire department’s standard procedures.
Most departments use the NFIRS or a variation.
Slide54Documentation and Reports
Basic report elements:
Incident numberAlarm time, date, and locationProperty ownershipBuilding construction/occupancy type
Weather conditions
Responding units and personnel
Slide55Preliminary Investigation Document
Information included:
Receipt of alarmResponse to the incidentAccessibility at the sceneFire suppressionCivilian contactsScene integrity
Slide56Investigation Report
Information provided in chronological order:
Description of the structure before the event Alarm notification informationResults of the fire scene examination
Slide57Investigation Report
Attachments to this report:
Information obtained from witnesses and respondersStatements of evidence WarrantsSketches
Slide58Legal Proceedings
The fire officer may be called on to testify in court as a witness.
Prepare by reviewing: ReportsPhotographsDiagramsPrevious depositions
© Corbis/age
fotostock
Slide59Legal Proceedings
Dress appropriately.
Follow the prosecutor’s directions.Sit up with both feet on the floor.Avoid gesturing.Keep answers short and to the point.
Slide60Legal Proceedings
Use language a jury can understand.
Be courteous and patient.Be honest.Do not hesitate answering questions.Speak clearly and loudly.If you do not remember, do not guess.
Slide61After the Fire Officials Are Gone
Many investigations continue long after the department has cleared the event.The fire investigator is interested in determining the cause and origin.Insurance company investigators may also be present.
Slide62Summary
To prevent future fires, it is important to understand the causes of past fires.The fire officer should be able to determine a point of origin and a cause. To determine the point of origin, the fire officer must understand fire growth and the three methods of heat transfer.
Slide63Summary
The fire investigator must take into account a citizen’s rights.A fire officer who suspects a crime should request a fire investigator.There are three types of evidence: demonstrative, documentary, and testimonial.
Slide64Summary
Fire scene reconstruction involves re-creating the scene before the fire occurred.The first step in fire cause determination is to identify the point of origin.Fire analysis involves examining fire occurrence.
Slide65Summary
Fire departments respond to more vehicle fires than structure fires.Wildland fires are influenced by environmental conditions.Fire cause classifications include accidental, natural, incendiary, and undetermined.
Slide66Summary
Arson is the crime of maliciously starting a fire or causing an explosion.All fires must be properly documented and reported.The fire officer often writes up a special report if the cause is incendiary or the circumstances are unusual.
Slide67Summary
In the investigation report, the information is provided in chronological order.Many fire investigations continue long after the fire department has cleared the event.