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Select Presentation Slides From:
Origin Matrix Analysis: A Systematic Methodology for Post-Fire Investigation and
Analysis of Compartment Fires
National Fire Protection Association Conference & Expo
Las Vegas, NV – June 2014
Additional Information May Be Obtained From: Cox, Andrew. “Origin Matrix Analysis: A Systematic Methodology for the Assessment and Interpretation of Compartment Fire Damage.” Fire and Arson Investigator, Journal of the International Association of Arson Investigators (IAAI), Volume 64, Issue 1, July 2013.
and/or Andrew Cox, Special Agent Bureau of Alcohol, Tobacco, Firearms and Explosives andrew.cox@atf.gov
Quadrant 1
Quadrant 4
Quadrant 2
Quadrant 3
FIRE ORIGIN
Open Doorway
FIGURE 1 – Hypothetical Compartment Fire
2
Quadrant 1
Quadrant 4
Quadrant 2
Quadrant 3
FIGURE 2 – Pre-Flashover Compartment Fire Conditions
Open Doorway
HEAT FUEL GASES
OXYGEN
FIRE
OXYGEN
NO FIRE
OXYGEN
NO FIRE
OXYGEN
NO FIRE
Reference: Figures 5.10.2.1-4, NFPA 921 Guide for Fire and Explosion Investigations, 2014 Edition.
Quadrant 1
Quadrant 4
Quadrant 2
Quadrant 3
FIGURE 3 – Flashover Compartment Fire Conditions
Open Doorway
HEAT FUEL GASES
OXYGEN
FIRE HEAT
FUEL GASES
OXYGEN
FIRE
HEAT FUEL GASES
OXYGEN
FIRE HEAT
FUEL GASES
OXYGEN
FIRE
Reference: Figure 5.10.2.6, NFPA 921 Guide for Fire and Explosion Investigations, 2014 Edition.
Quadrant 1
Quadrant 4
Quadrant 2
Quadrant 3
FIGURE 4 – Post-Flashover Compartment Fire Conditions
Open Doorway
HEAT FUEL GASES
OXYGEN
FIRE
NO FIRE
NO FIRE
NO FIRE
HEAT FUEL GASES
HEAT FUEL GASES
HEAT FUEL GASES
X
Reference: Figure 5.10.2.7, NFPA 921 Guide for Fire and Explosion Investigations, 2014 Edition. “X” Added by Presenter.
Flames will exist at the interface between the incoming fresh air (which contains O2) and the heated fuel gases that have accumulated inside the compartment.
Flames will NOT necessarily remain “attached” or even proximate to the solid and liquid fuels in the compartment.
Reference: NFPA 921 Guide for Fire and Explosion Investigations, 2014 Edition. Color Text and Diagramming Added by Presenter.
As depicted correctly, flames will exist at the interface between escaping heated fuel gases and the fresh air outside (which contains O2).
DAMAGE
What is Damage? Changes in materials resulting from a fire incident. Why are we Interested in Damage? Gives us clues about the nature of the fire that caused them.
1. Magnitude of Damage (Severity of the Cumulative Exposure) 2. Shape of Damage (Direction of Exposure)
NOTE: This language is slightly different than the “movement” and “intensity” terminology currently used in Section 6.4 Fire Pattern Analysis in the 2011 Edition of NFPA 921.
FACTORS AFFECTING MAGNITUDE OF DAMAGE
1. Exposure Duration.
2. Exposure Intensity.
3. Material Properties.
FACTORS AFFECTING SHAPE OF DAMAGE
The principles of heat transfer and fire dynamics will influence the shape of damage.
• Fire flows (Convection).
• Line of sight (Radiation).
• Materials (Material Properties, Construction Features).
Quadrant 1
Quadrant 4
Quadrant 2
Quadrant 3
FIRE ORIGIN
Open Doorway
FIGURE 1 – Hypothetical Compartment Fire
Quadrant 1
Quadrant 4
Quadrant 2
Quadrant 3
FIGURE 5 – Pre-Flashover Compartment Fire Conditions and Associated Cumulative Damages
Open Doorway
HEAT FUEL GASES
OXYGEN
FIRE
OXYGEN
NO FIRE
OXYGEN
NO FIRE
OXYGEN
NO FIRE
DAMAGE SCALE Light Heavy
Quadrant 1
Quadrant 4
Quadrant 2
Quadrant 3
FIGURE 6 – Flashover Compartment Fire Conditions and Associated Cumulative Damages
Open Doorway
HEAT FUEL GASES
OXYGEN
FIRE HEAT
FUEL GASES
OXYGEN
FIRE
HEAT FUEL GASES
OXYGEN
FIRE HEAT
FUEL GASES
OXYGEN
FIRE
DAMAGE SCALE Light Heavy
Quadrant 1
Quadrant 4
Quadrant 2
Quadrant 3
FIGURE 7 – Short Duration Post-Flashover Compartment Fire Conditions and Associated Cumulative Damages
Open Doorway
HEAT FUEL GASES
OXYGEN
FIRE
NO FIRE
NO FIRE
NO FIRE
HEAT FUEL GASES
HEAT FUEL GASES
HEAT FUEL GASES
DAMAGE SCALE Light Heavy
Quadrant 1
Quadrant 4
Quadrant 2
Quadrant 3
FIGURE 8 – Long Duration Post-Flashover Compartment Fire Conditions and Associated Cumulative Damages
Open Doorway
HEAT FUEL GASES
OXYGEN
FIRE
NO FIRE
NO FIRE
NO FIRE
HEAT FUEL GASES
HEAT FUEL GASES
HEAT FUEL GASES
DAMAGE SCALE Light Heavy
Quadrant 1
Quadrant 4
Quadrant 2
Quadrant 3
Regardless of where the fire starts, fires that burn well past flashover conditions are anticipated to present similar post-fire damages.
Open Doorway
HEAT FUEL GASES
OXYGEN
FIRE
NO FIRE
NO FIRE
NO FIRE
HEAT FUEL GASES
HEAT FUEL GASES
HEAT FUEL GASES
DAMAGE SCALE Light Heavy
FIRE ORIGIN LOCATION
Quadrant 1 Quadrant 2 Quadrant 3 Quadrant 4
FIRE GROWTH STAGE
Pre-Flashover
Flashover
Short Duration Post-Flashover
Long Duration Post-Flashover
TABLE 1 Andrew Cox, Special Agent
Bureau of Alcohol, Tobacco, Firearms and Explosives
FIGURE 9 – Depiction of Fresh Air Inflow During Post-Flashover Fire Conditions.
Open Doorway
C-Side Wall in Quadrant 2
21
Complications
Quadrant 1
Section 2
Open Doorway
DAMAGE SCALE Light Heavy
Quadrant 4
FIGURE C1-1 – Pre-Flashover Compartment Fire Conditions and Associated Cumulative Damages For Origin in Quadrant 1.
HEAT FUEL GASES
OXYGEN
FIRE
NO FIRE
HEAT FUEL GASES
NO FIRE
HEAT FUEL GASES
Quadrant 1
Section 2
Open Doorway
DAMAGE SCALE Light Heavy
Quadrant 4
FIGURE C1-2 – Flashover Compartment Fire Conditions and Associated Cumulative Damages For Origin in Quadrant 1.
HEAT FUEL GASES
OXYGEN
FIRE
HEAT FUEL GASES
OXYGEN
FIRE
HEAT FUEL GASES
OXYGEN
FIRE
Quadrant 1
Section 2
Open Doorway
DAMAGE SCALE Light Heavy
Quadrant 4
FIGURE C1-3 – Short Duration Post-Flashover Compartment Fire Conditions and Associated Cumulative Damages For Origin in Quadrant 1.
HEAT FUEL GASES
OXYGEN
FIRE NO FIRE
HEAT FUEL GASES
NO FIRE
HEAT FUEL GASES
Quadrant 1
Section 2
Open Doorway
DAMAGE SCALE Light Heavy
Quadrant 4
FIGURE C1-4 – Long Duration Post-Flashover Compartment Fire Conditions and Associated Cumulative Damages For Origin in Quadrant 1.
HEAT FUEL GASES
OXYGEN
FIRE NO FIRE
HEAT FUEL GASES
NO FIRE
HEAT FUEL GASES
FIRE ORIGIN LOCATION
Quadrant 1 Section 2
FIRE GROWTH STAGE
Pre-Flashover
Flashover
Short Duration Post-Flashover
Long Duration Post-Flashover
Three Analytical Divisions
Andrew Cox, Special Agent Bureau of Alcohol, Tobacco, Firearms and Explosives
Quadrant 4
FIRE ORIGIN LOCATION
Section 1 Section 2
FIRE GROWTH STAGE
Pre-Flashover
Flashover
Short Duration Post-Flashover
Long Duration Post-Flashover
Andrew Cox, Special Agent Bureau of Alcohol, Tobacco, Firearms and Explosives Two Analytical
Divisions
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