Fire Behavior and Arson Investigation

FIRE BEHAVIOR

Definition of Fire Behavior

• The way a fire burns, encompassing:

  • How fast it spreads

  • How much heat is emitted

  • How much combustible material it consumes

Three Main Factors of Fire Behavior

1. Fuel: Type of combustible material used.

2. Weather: Includes factors such as:

   • Wind

   • Temperature

   • Humidity

3. Topography: Considers the shape, slope, and direction of the land.

Dangerous Fire Behaviors

1. Backdraft

• Definition: A sudden and rapid burning of heated gases within a confined space, often resulting in an explosion.

• Causes: May occur due to improper ventilation, which sucks oxygen from outside leading to an explosion.

• Characteristics:

  • Presence of black smoke transitioning to dense gray-yellow smoke.

  • Confinement of excessive heat.

  • Smoke-stained windows.

  • Intermittent puffs of smoke escaping the building.

  • Muffled sounds indicative of intense heat.

  • Violent rush of air entering when doors or windows are opened.

2. Flashover

• Definition: A sudden ignition of accumulated flammable gases produced from incomplete combustion of fuels.

• Mechanism: Initiated by a spark or flash when the temperature rises to the flash point.

3. Flash Fire

• Definition: A fatal condition when a fire increases in intensity, resisting extinguishment efforts and growing larger.

• Known as: Dust explosion, which may occur when dust-covered metal is struck by lightning, causing simultaneous ignition of dust particles.

Three Stages of Fire Development

1. Incipient Phase

• Description: Initial stage of fire development characterized by:

  • Normal room temperature.

  • Thermal updraft rising to higher points.

  • Production of gases: CO2 (carbon dioxide), CO (carbon monoxide), SO2 (sulfides), water, etc.

  • Ample oxygen supply.

  • Temperature around $1000^{ ext{F}}$.

2. Free Burning Phase

• Description: A sustained burning phase where materials are actively burning in the presence of sufficient oxygen.

• Characteristics:

  • Fire mostly concentrated in the upper regions.

  • Accumulation of heat in the upper areas.

  • Complete coverage of the burning area.

  • Depleted oxygen supply.

  • Temperature exceeds $1330^{ ext{F}}$.

3. Smoldering Phase

• Description: Final phase when flames cease but dense smoke and heat fill the confined room.

• Characteristics:

  • Oxygen content below 13%, leading to extinguished flames.

  • Increased volume of products from incomplete combustion, especially carbon monoxide (ignition temperature around $1125^{ ext{F}}$).

  • Ceiling temperature between $1000^{ ext{F}}$ and $1300^{ ext{F}}$.

  • Accumulation of heat and pressure in the room.

  • Presence of large quantities of superheated fuel under pressure but with limited oxygen.

  • Potential for backdraft if sufficient oxygen is introduced.

Classification of Fires Based on Cause

1. Natural Cause

• Types:

  • Spontaneous Heating: Automatic chemical reaction leading to spontaneous combustion through the auto-ignition of organic materials, where heat gradually rises in a confined area until ignition occurs.

  • Lightning: A natural static electricity phenomenon with high magnitude resulting in significant amperage and voltage. Types include:

  • Hot Bolt: Longer duration, capable of igniting materials.

  • Cold Bolt: Shorter duration that may explode structures.

  • Radiation from Sunlight: Concentrated by a concave mirror onto combustible materials, igniting them.

2. Accidental Cause

• Types:

  • Electrical Accidents such as:

  • Short Circuit: Unusual connections between points of different charges.

  • Arcing: Electric hazard that involves luminous discharge across gaps between conductors.

  • Sparking: Incandescent particles generated from contacts between different charges.

  • Induced Current: Increase in electrical current leading to the burning of insulating materials.

  • Line Surge: Increase in electrical energy flow.

  • Overheating Electrical Appliances: Rise in amperage causing potential damage.

3. Intentional Causes

• Definition: Includes preparation and use of incendiary materials.

• Types:

  • Plants: Gathering combustible materials for arson.

  • Accelerants: Highly flammable chemicals facilitating fire spread.

  • Trailer: Flammable substances set to aid in fire dispersal.

Arson and Its Legal Aspects

• Definition: Intentional or malicious destruction of property by fire. Intent must be proved for a crime to exist.

• Destructive Arson (Article 320, RPC):

  • Imposes severe penalties for burning certain government properties and inhabited places.

Prima Facie Evidence of Arson

• Definition: Evidence sufficient to establish a fact unless rebutted.

• Indicators:

  1. Simultaneous fire starts in multiple areas of a building.

  2. Storage of flammable substances not relevant to business.

  3. Evidence of flammables or devices designed to start a fire found at the site.

  4. Overvaluation of insured property.

  5. Repeat incidents of fire at the same premises.

  6. Demand for money or valuables before the fire.

Basis of Criminal Liability in Arson

• Factors considered:

  1. Kind and character of the burned building.

  2. Location of the property.

  3. Extent or value of damage.

  4. Whether the building was inhabited.

Other Forms of Arson

• Defined under Article 321 of the RPC, includes:

  • Setting fire to occupied buildings, public buildings, or any structure with intent to destroy evidence.

Arson - Small Value (Article 323, RPC)

• Burning of uninhabited structures of negligible value (up to P25).

Statutes Regarding Destructive Acts (Articles 324 to 326, RPC)

• Various articles define destructive acts that may involve arson and the punishment for such actions.

Special Aggravating Circumstances in Arson (Section 4 - PD 1613)

• Defined criteria that exacerbate penalties in cases of arson. Includes:

  • Acts committed with intent to gain.

  • Actions taken for the benefit of another party.

  • Offender's motivation based on malice or spite.

  • Actions committed by a syndicate.

Elements Required to Prove Arson

1. Burning: Involves the process of pyrolysis leading to a change in materials.

2. Willfulness: Indicates intentional action.

3. Malice: Implies a desire for revenge.

4. Motive: The primary reason behind committing the crime.

5. Intent: The design behind the act of burning.

Legal Aspects of Arson/Fire Investigations

1. Investigators must establish malicious intent.

2. Presumption of accidents unless criminal design is proven.

3. Distinction between accidental and intentional fires must be delineated.

Methods of Proof in Arson Cases

• Need to establish the evidence of a crime. Essentials include:

  1. Burning Evidence: Witness testimony, evidence of fire location.

  2. Criminal Design Evidence: Presence of incendiary devices or flammable materials.

  3. Evidence of Intent: Actions taken before the fire or existing conflicts.

Basic Lines of Inquiry in Arson Investigation

1. Point of Origin: Crucial to determine where the fire started through various investigative techniques.

2. Motives of Arsonists: Possible economic gains, concealment of crimes, or punitive measures.

3. Signs of Arson: Observations indicating the fire was intentionally set and not accidental.

The Tell-Tale Signs of Arson

• Various indicators that may alert firefighters or investigators to potential arson, such as:

  1. Separate fire patterns.

  2. Distinct smoke colors signaling materials burning.

  3. Size and direction of flames.

  4. Heat levels indicating use of accelerants.

  5. Odor evidence from flammable substances.

Fire Origin Determination

• Accidental fires generally have a single origin; arson may display multiple origins. The most damaged area often indicates fire's point of origin.

Methods in Establishing Arson

1. Collecting, preserving, and analyzing evidence.

2. Identify and maintain evidence effectively.

3. Utilize time-delay devices as indicators.

4. Burn indicators like:

   • Alligatoring effect.

   • Crazing of glass.

   • Depth of char.

   • Smoke marks.

Technical Methods in Arson Investigation

• Various scientific tools and methods employed to analyze fire scenes.

  1. Chemical color tests.

  2. Catalytic combustion detection.

  3. Use of gas chromatographs.

  4. Infrared spectrophotometry.

  5. Ultraviolet fluorescence for residue analysis.

Definitions of Relevant Terms

• Presidential Decree 1185: Fire Code repealed by R.A. 9514.

• Presidential Decree 1613: Amended arson laws.

• Article 320, RPC - Destructive Arson

• Article 321, RPC - Other forms of Arson

• Article 322, RPC - Cases of Arson not included in preceding articles

• Article 323, RPC - Arson of property of small value

• Article 324, RPC - Crimes involving destruction

• Article 325, RPC - Burning one's own property as means to commit arson

• Article 326, RPC - Setting fire to property exclusively owned by the offender.

• Cellulose Nitrate/ Nitro Cellulose - highly combustible and explosive compound produced by the reaction of nitric acid with a cellulose material.

• Duct System - continuous passageway for the transmission of air.

• Fulminate - a kind of stable explosive compound which explodes by percussion.

• Jumper - a piece of metal or an electrical conductor used to bypass a safety device in an electrical

• Pyrophoric - Descriptive of any substance that ignites spontaneously when exposed to air.

• Smelting - Melting or fusing of metallic ores or compounds so as to separate impurities from pure metals.

• Sprinkler System - an integrated network of hydraulically designed piping installed in a building,structure or area with outiets arranged in a sysimate pattern which automatically discharges water when activated by heat or combustion products from fire.

• Standpipe System - a system of vertical pipes in a building to which fire hoses can be attached on each floor, including a system by which water is made available to the outlets as needed.

• Vestibule - a passage hall or chamber between the outer doors and the interior parts of a house or building.