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!!