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Fire Investigations:
The Basics
Anthony Cole, P.E., CFPS, CFEI
Presentation Outline
• What is a “fire investigation”?
• Fire chemistry and dynamics
• Causes of fires
• Investigative procedures
• Conclusions and questions
What is a “Fire Investigation”
• A complex endeavor involving skill, technology, knowledge, and science.
• A compilation of factual data as well as analysis of those facts… truthfully and objectively…. using a systematic approach and methodology
What is a “Fire Investigation”
• Origin
• Cause
• Responsibility
• Protect Property
The TRUE purpose of a investigation is to save lives by preventing reoccurrence
Fire Chemistry and Dynamics
• The Fire Triangle § Enough OXYGEN to sustain
combustion
§ Enough HEAT to raise the material to its ignition temperature
§ Some sort of FUEL or combustible material
§ This chemical, exothermic reaction is called FIRE
Fire Chemistry and Dynamics
• Flash Point: The lowest temperature at which vapors are given off at a sufficient rate to form an ignitable mixture at the surface but NOT sustain combustion.
• Fire Point: The lowest temperature at which vapors are given off at a sufficient rate to form an ignitable mixture at the surface but WILL sustain combustion.
Fire Chemistry and Dynamics
• Vapor Pressure: The pressure of the vapor exerted by a volatile liquid on the atmosphere above its surface. This is a characteristic of all liquids and is a direct indicator of the ability of the liquid to evaporate.
• Boiling Point: The temperature at which vapor pressure is equal or exceeds atmospheric pressure.
Fire Chemistry and Dynamics
• Autoignition Temperature: the lowest temperature at which a combustible material ignites in air without a spark or flame.
Fire Chemistry and Dynamics
TIME
RELEASE RATE
1 2 3 4
1. Incipient 2. Growth 3. Fully developed
4. Decay/burnout
Fire Chemistry and Dynamics
Qo
Qp
toto to
EXPONENTIAL T-‐SQUARED TRIANGULAR
• Exponential
• T-Squared
• Triangular
exp ( )
/
Q Q t t o o = -
τ
( ) Q t t o = - α
2
( ) Q t t o = - β
Fire Chemistry and Dynamics
• Fires in the open: klf = 1
• Fires along walls: klf = 2
• Fires in corners: klf = 4
Fire Chemistry and Dynamics
Flashover: A transition phase in the development of a compartment fire in which surfaces exposed to thermal radiation reach ignition temperature simultaneously and fire spreads rapidly throughout a space.
The result of a flashover is full room involvement.
Fire Chemistry and Dynamics - Fire
• Yellow
• Orange
• Red
• White
• Green
• Blue
Ordinary combustible (class A)
Later stage class A
Flammable/combustible liquids
Metals
Cooper and nitrates
Alcohol and natural gas with proper mixture of air
Fire Chemistry and Dynamics – Smoke
• Hay
• Benzene
• Sulphur
• Sulfuric/hydrochloric acid
• Chlorine gas
• Wood
• Hydrocarbons
White
White to gray
Yellow to brownish yellow
Yellow to brownish yellow
Greenish yellow
Gray to brown
Black
Fire Chemistry and Dynamics
Fire Chemistry and Dynamics
Fire Chemistry and Dynamics
Fire Chemistry and Dynamics
Fire Chemistry and Dynamics
Fire Chemistry and Dynamics
Fire Chemistry and Dynamics
Fire Chemistry and Dynamics
Causes of Fires - Industrial
Causes of Fires - Apartments
Causes of Fires – Single Family
Investigative Procedures
Investigative Procedures
• Systematic approach
• Recognize the need
• Define the problem
• Collect data
• Analyze the data
• Develop a hypothesis
• Test the hypothesis
• AVOID Presumption of cause
Investigative Procedures
• Recognizing the need
• Preparing for the investigation
• Conducting the investigation
• Collecting and preserving evidence
• Analyzing the incident
• Conclusions
• Issuance of a report
Investigative Procedures – Recognizing the need
• Fleeing persons or vehicles:
On foot – height, weight, clothing, or distinguishing characteristics.
Car – make, model, year, color, license plates, or any notable information.
• Forced delays:
Blocked street or access
False alarms in the area
Timed/coordinated response
Investigative Procedures – Recognizing the need
Windows or door -
• Opened
• Broken
• Forced
“Burglar” tools?
• Closed
but not locked
locked (bolt and chain)
Investigative Procedures – Recognizing the need
• Watch persons at the scene
• Listen to what observers are saying
• Look for “unusual” items
• Be alert to spectators who offer “help”
Investigative Procedures – Preparing for the Investigation
• Organize the investigation team (experts)
• Organizing resources
• Documentation
Investigative Procedures – Conducting the Investigation
• Photos • Video • Evidence • Third party testing • Documentation FIND THE FACTS!!
Tools of the Trade
Tools of the Trade
Tools of the Trade
Investigative Procedures - Conclusion
• State the facts!
• Present report clearly
Conclusion
• All fires should be investigated
• Look for FACTS
• Call the experts
• Be “open-minded”
Resources
• NFPA 921 “Guide for Fire and Explosion Investigations”
• Kirks’ “Fire Investigation”
• Kennedy’s “Fire and Arson Investigation”
• Beveridge’s “Forensics Investigation of Explosions”
• Noon’s “Engineering Analysis of Fires and Explosions”
• Phillips/Mcfadden “Investigating the Fireground”
• www.NFPA.org
• www.NAFI.org
• www.KENNEDY-FIRE.com • www.DOCTORFIRE.com
• www.ROBSONFORENSIC.com
Thanks!!