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Flashcards in Arson Detection Deck (30):

Incendiary fire is

A designation given to the fire in which the fire Marshall has determined through physical examination of the fire scene and interview with witness that fire was intentionally set by someone


Suspicious fire is

A designation given by the IC in command of the fire operation and is one of the circumstances in which a fire Marshall is called to the scene to investigate and determine the cause origin and circumstances of the fire


A fire is suspicious if

1. Indication that the fire has been set and all accidental cause have not been eliminated ( when all accidental causes eliminated fire is incendiary )
2. A threat proceeding fire
3. One in a series of similar fires
4. Premise normally locked are found unlocked
5 . Stock or belongings we're removed prior to fire . Any act or circumstances which cannot be explained and which tends to indicate that the fire may be intentionally set


Trailers are

Material arranged to spread fire fro it's point of origin to other areas of the occupancy
Cotton waste, rags ,paper, fluids excelsior , waste film and others )



Material arranged to start and feed he initial fire
Candles matches electrical mechanical chemicals and others



Gasoline kerosene turpentine alcohol paint thinner cut or disconnected gas lines


Ignition devices are

Mechanical chemical or electrical means to imitate a fire


Protected areas

The clean unburned area left by stock furniture contents etc covering shelves floors or other combustible areas


If occupants claim they were in bed at time of the fire you should observe what about them

Notice there dress such a as shoes being laced and tied and if wearing ties


Who determines a fire to be incendiary

Fire Marshall


If the fire is deemed suspicious by IC a fire Marshall is called to the scene to determine

Cause origin and circumstances of fire


Following are indications of the use of flammable accelerants

1. Charring on the floor or low burn marks on the wall or under the door or on the lower part of the door
2. Char in broken patterns or " puddle like " circle burns on the floor
3.low burning and deep charring
4. Heavy body of fire with little contents


When recording info from occupants and witness you should

Don't not interrogate let them talk freely
Get names and addresses if possible
Do not put names or statements of witness on the face of fire reports


Relatives neighbors spectators the media and members of the department shall not cross established fire lines unless authorized by

The assigned fire Marshall and or chief of ops


The fire scene investigation may involve 3 individual investigations which are

1. Fire origin
2. Fire cause
3. And fire death investigation


Who makes the cause of death determination

The fire Marshall and the medical examiner


Absence of CO in the blood could indicate death prior to the fire Signs the of co In blood are

1. May cause victims to appear life like
2. Pink to cherry red color of lips eyelids or skin


Lividity is cause by settling of the blood to the lowest horizontal areas of the body and may

Show as pink or red skin ( do not confuse with cheery red skin of co poisoning)
Usually starts one to,two hours after death and is completed 3 to,4 hours after
Could indicate victim was moved after death and placed at scene


Signs that victim may have been alive before fire

Skull exploding outward
Pugilistic pose
Shoot around nose
Pink or cheery red skin
Victim found in unburned areas


Safeguarding evidence

Use a completely air tight container made from non- odorous materials
Container should be a one gallon metal can such as a new paint can ( never used on ethane was previously used !
No new can a use clean glass jar with tight fitting lid
Try to avoid using plastic containers
Plastic bag may be used in emergency it should be new heavy gauge and used in pairs(ASAP place into can or jar )


Continuity of evidence

1. Where possible do not remove evidence before arrival of fire Marshall
2. Request photo unit to take pics of evidence if a Marshall not responding
3.label and mark evidence and note where it was found at he fire scene NEVER Label mark or alter any evidence in any way prior to,photos
4. Evidence cannot be left in office unless it is locked or someone signs and remains with evidence


Point of origin

Where fire started and at this point it can usually be determined if fire was accidental or incendiary in nature
May be an exact point or a general area( accelerant )



May help id point of origin
Usually point towards point of origin
Absence of V-pattern may be an indication that accelerant used (accelerant may cause perpendicular burns)
Most fires have v-shaped patter with apex at. Bottom this pattern may be altered by the presence of any obstructions or of readily burned fuel in localized areas


Heavy smoke stains remote form the point of origin usually indicate

Slow fire build up


Light smoke stains usually indicate

A rapid build up of fire
Little fire damaged
And are found close to the point of origin
Hydrocarbon fires may be the exception ( which is. Most of today's fires )


What are the highest priority fires for fire Marshall's

DOA fires
Incendiary commercial fires


Small crazing of glass indicates

Intense rapid heat build up and will be found closer to point of origin


Large glass crazing indicates

Remoteness form point of origin and or relatively slow heat build up


Checkering of glass is an indication half moon or effects or marks

Usually results form water being applied to heated glass
Indicated glass was in place when ffs operated at fire


Depth of charring as an indicator of fires travel and point of origin

Wood structural May burn ~1 " every 45 min
Depth of charr may indicate time burned
Deepest charr may be found at point of origin , not always true cause deepest char may be above point of origin
Smaller blistering type charring may indicate longer burning at hot fires