Flammable liquids : Flammable liquids 14:12 1 Corners and wall to floor edges may be dead air spaces which suffer little, if any fire damage unless flammable liquids are present
May carry flames behind baseboards or moldings, these should be removed and examined
Flammable liquids : Flammable liquids 14:12 2 The charring of the undersides of furniture usually indicates that the fire was burning below the furniture, possibly fed by an accelerant however this can be misleading because of the various types of foam padding
Firefighters may have witnessed flashbacks in areas saturated with flammable accelerants
Flammable liquids may soak into floors and cause burn holes often of irregular shapes
May even follow the direction of flooring joists
Flammable liquids may produce a flashover appearance, pattern is usually evenly burned if due to a flashover, but uneven with flammable liquids
Charring : Charring 14:12 3 No such thing as alligator char (old firefighters’ tale)
Misconceptions about appearance
Large shiny blisters = ignitable liquid
Dullness, shininess or colors = ignitable liquid
Depth of char = accurate estimate of duration of fire
Charring : Charring 14:12 4 The rate of charring of wood varies widely depending upon such variables as:
Rate and duration of heating, ventilation effects, surface to area mass ratio, direction of fire travel, orientation and size of wood grain.
Species of wood, moisture content, nature of surface coating.
No specific time of burning can be determined based solely on depth of char.
Old adage that older houses burn quicker since the wood is drier is not true, since old and new wood will have approximately the same moisture content in the wood making the burn rate similar.
Charring : Charring 14:12 5 The charring of the undersides of furniture usually indicates that the fire was burning below the furniture, possibly fed by an ignitable liquid / accelerant however this can be misleading because of the various types of foam padding.
Foam padding sometimes during fires liquefies, drops down, then spreads making burn patterns similar to a poured ignitable liquid fire.
In the next 2 frames are photos of a Futon padding liquefying resulting in a similar pattern of a burning ignitable liquid trailer, and a chair with the foam padding liquefied on the floor .
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Charring : Charring 14:12 7
Charring : 14:12 8 Charring
Ignitable Liquid Containers : Ignitable Liquid Containers 14:12 9
Ignitable Liquid Containers : Ignitable Liquid Containers 14:12 10 May provide comparison sample for lab
If container is not damaged may prove spread of accelerant was not due to explosion of that container
Often latent fingerprints can be obtained from the containers
Responders may have noticed flammable liquid odors. Sometimes during overhaul a pocket of unburned accelerant is exposed
Indicates may have been used in early stages of a fire
Common Equipment/ appliances Used As Incendiary Devices : Common Equipment/ appliances Used As Incendiary Devices 14:12 11
Common Equipment/Appliances : Common Equipment/Appliances Heating and cooking equipment
Lighting
Combustible fuel arranged nearby
Small appliances unusual location / tampering
Smoking materials, difficult to prove intent 14:12 12 GAS WATER HEATER
Toasters : Toasters 14:12 13
Coffee Makers : Coffee Makers 14:12 14
Slide 15 : 14:12 15 ELECTRIC HEATER INSIDE CLOSET
Removal or Substitution of Contents : Removal or Substitution of Contents 14:12 16 Expensive objects, antiques, or objects with sentimental value
Substitution with “junk”, hope will be destroyed by fire
Maybe witnessed by neighbors
Contents out of place or not assembled
Major appliances removed or replaced
Absence of Personal Items or Important Papers : Absence of Personal Items or Important Papers 14:12 17 Hand tools
Power tools
Work clothing
Business machines
Guns
Petty cash
Expensive clothing
Jewelry
Photographs Family records
Hobby/sports equipment
Insurance policies
Marriage and church records
Checking and savings account records
School records
Wills
Absence of Personal Items or Important Papers : 14:12 18 Absence of Personal Items or Important Papers
Absence of Personal Items or Important Papers : 14:12 19 Absence of Personal Items or Important Papers
Absence of Personal Items or Important Papers : 14:12 20 Absence of Personal Items or Important Papers
Unnatural Fire Spread, Excessive Damage and/or Extreme Heat : Unnatural Fire Spread, Excessive Damage and/or Extreme Heat 14:12 21 “Unnatural” fire spread may be due to an ignitable liquid
Excessive or unusual fire damage compared to similar fires
Excessive or unusual heat levels compared to similar fires
Heat Levels : Heat Levels 14:12 22 Structural fires can produce temperatures up to and above 1,900 degrees F
Such temperatures usually occur in later stages of fire such as the flashover stage during the fully developed phase of the fire, (not every fire reaches flashover)
Melting of metals may also indicate unusual temperatures
Melting Temperature : Melting Temperature 14:12 23
Limited Entry or View : Limited Entry or View 14:12 24 Slow firefighter entry due to blocked, nailed, bolted, wired shut doors & windows, contents moved to block entry, etc.
Delayed detection of fire due to blacked out windows, time of day, location of structure, etc.
Also this delays firefighter response
Time Between Exit of Occupant and Fire : Time Between Exit of Occupant and Fire 14:12 25 Reasonable
Appropriate
Believable
Long delays may indicate arson
Timing of Incendiary Fires : Timing of Incendiary Fires 14:12 26 Fires on holidays or weekends at commercial properties
Time of day
Convenient ignition source
Fires during renovations/remodeling
Fires during electrical storms or bad weather
Fires while occupants away from home
Incendiary Devices : Incendiary Devices 14:12 27 Incendiary device is an electrical, mechanical, or chemical device used to initiate combustion
Delay mechanism is any element that provides delay to allow arsonist to be away when the fire begins
Incendiary material is one which burns with a hot flame for a period of time initiating the fire process
Construction : Construction 14:12 28 Often made from readily available materials
When used separately, materials may be harmless
Materials may be found in everyday use or materials normal to occupancy
Electrical : Electrical 14:12 29 Almost any electrical device can be used as part of an incendiary device
Used to produce spark, heat or activate some other device
A dry cell battery could be used to heat a coil which would ignite nearby chemicals
Common Examples : Common Examples 14:12 30 Light bulbs placed close to combustibles, (light bulb filaments typically reach approximately 3000 degrees)
Heating equipment
Coffeemakers
Toasters
Toaster ovens
Clothes irons
Telephone devices
Mechanical : Mechanical 14:12 31 Clocks and timers
May be used in conjunction with chemicals, ignitable liquids or electrical circuits
Mousetraps with one wire on the trap, the other on the bail to make contact when tripped completes an electrical circuit
Clothes pins, one wire on each side of an open pin designed to close when tripped completing an electrical circuit
Chemical : Chemical 14:12 32 Granulated sugar and potassium chlorate ignited by sulfuric acid
Granulated sugar and sodium peroxide ignited by water or sulfuric acid
Aluminum powder and sodium peroxide ignited by water or sulfuric acid
Silver nitrate and magnesium powder ignited by water or sulfuric acid
HTH chlorine ignited with brake fluid or glycerin
Common Devices : Common Devices Cigarette and match delay
Highway flares reach temps up to 1200 degrees
Molotov cocktails, fuel, breakable container, igniter (wick). Often fail to function. Fuel usually mixed - kerosene, fuel oil, Ivory Snow flakes.
Produces limited spread , causes sticking of accelerant to target 14:12 33
Common Devices : Common Devices 14:12 34 50/50 mixture of sugar and potassium chlorate is combined with water to form a paste. Rag is soaked in paste wrapped around bottle allowed to dry.
When thrown ignites on impact, may be delayed while heat of ignition is produced
Availability of Information : Availability of Information 14:12 35 Internet
Poor Man’s James Bond
Anarchist’s Cookbook
Military Ordinance Manuals
Mercenary magazine
Mail order companies
Incendiary Vehicle Fires : Incendiary Vehicle Fires Vehicles fires can and do occur accidentally
Accidental fires can and do result in total destruction of the vehicle 14:12 36
Factors : Factors 14:12 37 Economic conditions
Ownership
Financed
Insured
Injuries
Time
Location
Indicators of Incendiarism : Indicators of Incendiarism 14:12 38 Trailers
Containers
Shoeprints
Skid marks
Gas cap
Doors and window positions Keys
Locks
Steering column
Accessories
Tires
Contents of trunk, glove compartment
Indicators of Incendiarism (Cont’d) : 14:12 39 Indicators of Incendiarism (Cont’d)
Indicators of Incendiarism (Cont’d) : 14:12 40 Indicators of Incendiarism (Cont’d)
Engine Compartment : Engine Compartment 14:12 41 Radiator and cooling system
Belts and hoses
Accessories – parts
Normally do not burn during a fire that is not arson
Investigation of a structure fire from start to finish : Investigation of a structure fire from start to finish Be very careful of your surroundings, wear appropriate protective equipment.
Do not enter if the structure looks unsafe
Always try to have another person present while conducting an investigation.
Burned structures are unpredictable as to collapse, falling objects, unstable flooring, protruding sharp objects, as well as a hazardous materials environment involving a lot of toxic materials and fumes. 14:12 42
: Photo the outside perimeter and surrounding area in a systematic order keeping a log and description of every photo before making entry.
Photo making entry into the structure.
Begin the investigation and photo from the area of least damage working toward the area with the most damage. This generally is the point of origin of the fire.
Photo in a systematic order the interior keeping a log and description of every photo. Using film or digital cameras, do not leave out or delete any photos, no matter how bad the photo. We are human and make mistakes, if an attorney asks if these are all of your photos you can truthfully answer yes. 14:12 43
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: All tools used for gathering evidence must be cleaned prior to first use and before gathering each additional sample.
ATF recommends Dawn dishwashing liquid to clean your tools.
ALWAYS wear clean nitrile, or latex gloves for every sample, or handling evidence, changing gloves before each sample to prevent cross contamination
Photo each item before placing any type of evidence marker
Photo after placing evidence marker
Photo taking sample and placing in proper evidence container 14:12 52
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: After making the determination of where to begin taking evidence samples, the debris must be carefully removed so not to toss out evidence.
Shovel down to floor level, sweep or use a fire hose to wash the floor, being aware of potential evidence that may be taken away by either method.
Washing the floor is the preferred method with a low water pressure of about 50 p.s.i.
Photo this operation 14:12 54
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