Presentation on theme: "Fire Patterns associated with Ignitable Liquid Accelerants"— Presentation transcript:
1 Fire Patterns associated with Ignitable Liquid Accelerants Fire and Arson InvestigationFire Patterns associated with Ignitable Liquid AccelerantsByBob Corry
2 of a fire scene examination is the recognition, identification “One of the major objectivesof a fire scene examinationis the recognition, identificationand analysis of fire patterns.”NFPA 921 (2004)4.1
3 Success in Recognizing Arson begins with recognizing possible Arson Fire Patterns
4 NFPA 921 on Fire PatternsHoles in the floor may be caused by glowing combustion, radiation or an ignitable liquidThere is no justification that the appearance of large, curved blisters is an exclusive indicator of an accelerated fireThe presence or absence of spalling should not, in and of itself, be construed as an indicator of the presence or absence of a liquid fuel accelerantThe collapse of springs cannot be used to indicate exposure to a specific type of heat source or ignition such as smoldering ignition or the presence of an ignitable liquid. 6.14Inverted cone patterns have been interpreted as proof of flammable liquid fires, but any fuel source that produced flame zones that do not become vertically restricted can produce inverted cone patterns
5 First! Search for Odd Variations in Fire Patterns Unusual “localized”wall patternUnusual,localizeddamageto the bedUnusual floorburn pattern
6 Furniture moved before fire! Witnesses Reported:Odor of Gasoline!A low pressure wave!Furniture moved before fire!
7 or hair of a suspect/witness. Symptoms of Ignitable Liquid Use (Possible indicators of an accelerated fire)Burn injuriesto thehands, face, legsor hair of a suspect/witness.
8 (downward, unusually fast, etc.) Unnatural Fire Spread(downward, unusually fast, etc.)Afternoon Program
9 “Unnatural” Fire Damage One gallon of gasolinewas poured here!
10 Bright yellow/orange flames accompanied by black smoke.
11 Intense localized rusting/warping, especially to the undersides of metal objects within the pattern
12 especially to the undersides of Intense localizedrusting/warping,especially to the undersides ofmetal objectswithin the pattern
24 Key Properties of Common Ignitable Liquids Behave like any liquid before ignition.Most float on water, are immiscible, rainbowForm explosive vapors at room temperaturesVapors are heavier than airReadily absorbedPowerful solventsDon’t spontaneously igniteExplosive Limits/Ignition TemperatureSampling the accelerant fire pattern
25 Related Physical Evidence The Accelerant ContainerOther instrumentalities (i.e. ignition device)Changing the arrangement of combustibles to increase fire loadingPropping open doors & windowsThe ignition deviceExplosion/Deflagration?Burn patterns and the burned “perp”