ARSON. Do Now: What is arson? Fill out the video questions. We will finish tomorrow. Closure: What...

Do Now: What is arson?

Fill out the video questions. We will finish tomorrow.

Closure: What causes a back draft?

Objectives: discover what arson is and how it is investigated.

Do Now: What is the point of origin?

Fill out the video questions and hand them in.

Complete the Case study on the “Serial Arsonist” and hand it in.

Closure: Why is it so hard to catch an arsonist?

Objectives: discover what arson is and how it is investigated.

Do Now: Name at least one of the three things fire needs in order to continue burning.

Objectives: Identify the Mechanism for Arson

Fire Produced when a substance undergoes rapid oxidation involving heat and light

ArsonThe deliberate or purposeful act of starting or accelerating a fire


In 2010, 384,000 fires occurred in homes in the United States

Most victims die from smoke or toxic gases and not from burns

Smoking is the leading cause of fire related deaths

Cooking is the major cause of house fires


Fuel + Oxygen + Heat = FireThe Fire Triangle represents the

three elements needed for fire to occur: heat, fuel, and oxygen.

FUEL

OXYGENHEAT


FuelFuel can be any combustible (substance that easily catches fire) material in any state of matter - solid, liquid, or gas.

Most solids and liquids become a vapor or gas before they will burn.

Examples: Clothing, furniture, curtains, flammable liquids


OxygenThe air we breathe is about 21% oxygen. Fire requires an atmosphere with at least 16% oxygen.


Heat is the energy necessary to increase the temperature of the fuel to a point where sufficient vapors are given off for ignition (spark that starts the fire) to occur.

Examples: Stoves, heating appliances, fireplaces, damaged wiring


Complete the “Tools Used in Arson Investigation” handout and hand it in. However, you may need your handout for the closure.

Closure: Explain how Photo ionization detectors work. (You may need your handout.)


Do Now: Explain how dogs can be used when investigating fires.

Take out your Arson notes!

Objectives: Identify Fire Investigation Protocol

Role of Fire Investigator:

Is the scene safe?

Evacuate the scene

Protective clothing

Turn off gas and electricity

Interview witnesses

Suspicious activity

Color of fire or smoke

Video and photographs


Work from the least damaged areas to the most heavily damaged areas.

Document with notes, photographs, and videos.

Examine doors, windows to see whether or not they were locked during the fire


Collect evidence (accelerant samples, fire items, and other crime scene evidence.)

Determine the point of origin. Establish point of origin – the area where the fire started will tend to burn for a longer period of time and have the worst damage

Determine the heat source(s).

Hypothesize the reasons for the fire.


Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) is a Federal Agency responsible for:

administering and enforcing the criminal and regulatory Federal laws pertaining to destructive devices (bombs), explosives, and arson.

studies science and technology related to detecting explosives, effects of explosives, behavior of explosives and explosive devices


Point of Origin Burn patterns and other damage can help determine the point of origin, or the location where the fire started.

Char Patterns Created by very hot fires that burn very quickly and move fast along its path, so that there can be sharp lines between what is burned and what isn't. A char pattern on a door would help an investigator determine which side of the door the fire was on.A char pattern on the floor would help investigators determine the use of an accelerant and its path.


V-Patterns - Fire burns up, in a V-shaped pattern, so a fire that starts at an outlet against a wall leaves a char pattern that points to the origin.

A very narrow V-shape might indicate a fire that was hotter than normal, such as one helped along by an accelerant.

A wide V-shape might indicate a fire that was slow burning.

A U-shape could indicate that there was a "pool of origin" rather than a point of origin, such as might be caused by, say, a puddle of gasoline.


Heat Shadows - Occur when heavy furniture shields part of a wall; can

help determine the origin point.

Glass - Glass fragments, windows, and light bulbs can provide clues to a

fire.

Light bulbs tend to melt toward the heat source, so the "direction of

melt" can indicate the direction of the fire.

The shattered or cracked glass of the windows can provide

indications as to how a fire burned.

A dark soot layer on the glass could indicate a slow, smoldering fire.

Clear glass with an abnormal pattern of cracking could imply a very

hot fire, possibly due to an accelerant.


Chimney Effect – Since fire burns upwards, there can be a "chimney effect" where the fire ignites at a point, the superheated gases rise upward and form a fireball, which continues straight up to burn a hole in the ceiling. If the roof is not entirely burnt, and the fire investigator finds such a hole, the origin of the fire

could be directly underneath.


Color of smoke – Determine what type material was burning

Color of flames – Indicates at what temperature and chemicals were burning during the fire.

Example: red/orange/yellow flame – carbon was present, inorganic substances vary in color.


Accidental Nature of FiresHeating System Electrical appliances LightningChildren playing with matchesSmoking


Non-Accident Odors – Gas, kerosene, or other accelerantsFurnishing – Removal of personal objects and valuablesClothing – Check debris for buttons, zippers, etc.Locked windows, blocked doorsTwo or more points of originLook for inverted v-patterns (can be a sign that an accelerant was used)Floors charred –Can indicate use of an accelerantTrailers that lead the fire from one place to another


Motives For Arson• Crime concealment: To conceal another crime such as murder, burglary, or

vehicle.

• Revenge or spite: To get back at someone for a perceived injustice.

• Monetary Gain: Arson-for-Profit fires are set to burn a building, vehicle, or some other object in order to gain profit from the fire. The profit may come in several forms; from insurance coverage on the property, or from putting a competitor out of business

• Malicious Vandalism: Fire set to someone’s property, just to destroy it. Malicious vandalism fires account for the largest percentage of arson fires. These fires are frequently set by juveniles.

• Mentally Disturbed: Some persons have been found to have an irresistible impulse to set fires. – Pyromaniac


Complete the Case Study on serial arsonists and hand in.

Complete Test Corrections and hand in.

Closure: Describe two reasons why someone might commit arson.


Objective: you will be able to identify the characteristics of a

flame

A candle flame has three main zones. They are:

Outer zone

Middle zone

Inner zone

In the outer zone

complete combustion of the fuel takes place

The color of the flame is blue and is the hottest part of the flame.

It is the non luminous part of the flame.

Objective: you will be able to identify the characteristics of a flame

In the middle zone

partial combustion of the fuel takes place

the color of the flame is yellow

is moderately hot part of the flame.

it is the luminous part of the flame.

In the inner zone

Un-burned vapors of the fuel

the color is black

is least hot part.

Hottest part

Moderately hot

Least hot

Outer zone (blue)Non luminous zone

(Complete combustion)

Middle zone (yellowLuminous Zone(Partial combustion)

Inner zone (black)

Unburned wax vapors

Structure of a

Candle Flame

ARSON. Do Now: What is arson? Fill out the video questions. We will finish tomorrow. Closure: What...

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