Section 20 - Fire Cause Detection

Question 1

3 sides of the Fire Investigation triangle

Answer 1

• Firefighters
• Police Dept.
• the Arson Investigator

Question 2

Firefighters Observations at fire scenes such as:

Answer 2

• Are there any vehicles leaving the scene (or individuals)-
• What’s burning and where?
• What colour is the smoke or flames?
• How and where did you enter the building?
• How many fires?
• Is water supply ok?
• Anything unusual or foreign to the area during fire or mop-up?

Question 3

The second triangle (the fire Dept. Investigator)

Answer 3

• Police Dept.
• Provincial Investigators
• Fire Dept. Investigator

Question 4

Assembling the facts of a fire scene….. requires help of many different people.

Answer 4

• Firefighters
• Officers
• Chiefs
• Investigators
• Police
• Insurance Companies
• Lawyers

Question 5

To establish the cause of a fire, we must determine 3 things…

Answer 5

1-Determine the fire spread
2-Determine the point of origin
3-Cause determination
(i) source of ignition
(ii) combustible materials present
(iii) the act

Question 6

Fire and heat may spread throughout a building either by…

Answer 6

• Conduction
• Convection
• Radiation
• Actual Flame Contact

Question 7

Fire Spread

Answer 7

Fire can travel up the outside of concrete and brick building vertically, floor by floor, via windows and not spread horizontally through floors. Fire can also spread horizontally between floor joists, between ceilings and floors, through attic cocklofts, along beams, through furnace ducts. The fire may also spread by flying embers or debris.

Question 8

Fire Burns upwards

Answer 8

Preheated gases and fire unobstructed and under normal conditions, always travel upwards seeking the highest point.

Question 9

Point of Origin

Answer 9

To determine the point of origin we must locate the lowest point of burning in the building with the greatest amount go of charring.

Remember that fire can travel Horizontally or downwards to reach a source of oxygen

Question 10

Once you have established the point of origin, you must ask yourself 3 questions.

Answer 10

1-What combustible materials were present?
2-What is our ignition source?
3-What act brought these together? (Providential, Accidental, Intentional)

Question 11

Principle cause of fire

Answer 11

2 conditions being permitted to come into contact,

an ignition source and a fuel supply

Question 12

3 sides to a fire triangle theory(fire ignition sequence)

Answer 12

• Heat source
• Fuel
• the Act

Question 13

The Act - Providential, Accidental, Intentional

Answer 13

Providential - acts of nature
Accidental - careless use of smoking materials, improper use of flammable liquids, faulty appliance
Intentional - Incendiary fires are arson, a criminal act.

Question 14

3 things that must be identified separately if the fire cause is to be fully explained.

Answer 14

• ignition source
• combustible materials
• the act

Question 15

Black smoke

Answer 15

indicates a lack of air

Question 16

Black smoke with large red flames

Answer 16

generally indicates the burning of a material with petroleum base.

Question 17

No flames or comparatively small flames indicates

Answer 17

lack of air.

Question 18

10 steps to follow in fire observations

Answer 18

1- One of the prime responsibilities of FF is to determine the origin and cause of fire
2- Realize that you and your officers are the first eyes on the fire scene
3- Observe the unusual - what is present that wouldn’t normally be there? What isn’t present that normally would be there
4-Be quick to observe vehicles or persons leaving the scene as you are arriving
5- the first impressions of what you see on arrival is critical such as smoke, flame, etc.
6- Is the building secure? How and where was entry made? Is their indication of forcible entry prior to your arrival
7- Where is the main body of the fire? Does there appear to be more than one fire burning?
8-Is the fire harder than normal to extinguish? Does it keep on reigniting?
9-What can you smell that seems odd?
10-What did people say to you and can you positively assure that you or an investigator can locate these people later if necessary?

Question 19

200-watt bulb

Answer 19

base up mounting - 307F (163C)

side mounting - 493F (256C)

Question 20

Is guilty of an indictable offence, and is liable to imprisonment for 14 years….

Answer 20

Everyone willfully sets fire to:

• a building or structure, whether complete or not
• a stack of vegetation produce of mineral or vegetable fuel
• a mine
• a well or combustible substance
• a vessel or aircraft, whether complete or not
• timber or materials placed in a shipyard for building, repairing or fitting out a ship
• military or public stores or munitions of war
• a crop, whether standing or cut down
• any wood, forest or natural growth or any lumber, timber, log, float, boom, dam or slide

Question 21

Everyone who willfully and for fraudulent purposes sets fire to personal property not mentioned in subsection 1 is guilty of an indictable offence an is liable to imprisonment for…..

Answer 21

5 years

Question 22

Everyone who willfully sets fire to anything that is likely to cause anything mentioned in subsection 1 to catch fire: or willfully and for a fraudulent purpose sets fire to anything that is likely to cause personal property not mentioned in subsection 1 to catch fire, is guilty of an indictable offence and is liable to imprisonment for…

Answer 22

5 years

Question 23

6 Main reasons for Incendiary or arson fires

Answer 23

1-Profit or economic gain by defrauding the insurance company
2-Economic gain where the assured is innocent but the perpetrators benefits
3-Personal satisfaction has cause numerous and costly fires
4-Arson to conceal another crime
5-Arson by the mentally afflicted, such a pyromaniacs, etc.
6-Miscellaneous Circumstances

Question 24

Exclusion of Accidental Causes

Answer 24

• the Electric system
• Electric Equipment-broken and rotted insulation, overloading circuits
• Gas leaks in piping or defective equipment.
• Pets
• Heating equipment
• Sun
• Lightning
• Children
• Smoking
• Storage of hay

Question 25

3 vital questions in any investigation of fire setting

Answer 25

- Identity of the witnesses - their business in the area - what attracted their attention to it

Question 26

Forces that cause fire to happen

Answer 26

-Combustibles involved -Openings and Ventilation -Winds and Draught -Explosions -Variations from normal Burning -

Question 27

How to retrace or reconstruct the path of fire by the effects produced

Answer 27

- Charring - Remains and debris - Room temperature - sequence of shorted electrical circuits - sequence of sprinkler eruptions - the interiors of partitions - feeling change in wall temps - Adjoining properties - the path may often be reconstructed by damage done to adjoining properties - Colour of smoke and flames

Question 28

Fire Cause Detection - All firefighters should note

Answer 28

- persons or cars leaving the scene or present upon arrival of apparatus - whether doors or windows were open, unlocked or locked when entrance was made - any disarrangement of furnishings or contents, drawn shades or the absence of valuable or personal articles or pets which are ordinarily present. - the attitude of owner r occupants and any statements made by them - unusual bystanders, particularly those seen at other fires and those who appear unduly excited or interested as to the cause of the fire - all evidence and preserve it until the arrival of the investigator

Question 29

Fire Cause detection - The fire officer in charge should:

Answer 29

- have notes made as facts are reported to him (small details may later become important to the trial of a case) - take prompt and proper action when fire is deemed suspicious, particularly in guarding the scene until the arrival of investigators - ensure entry to the building be denied to all persons except firefighters and police officers until the arrival on investigators - seek to determine the exact point of origin, taking particular note if there is any indication of more than one point of origin.

Question 30

Fire cause detection - Firefighting personnel should not!!!

Answer 30

- move, remove, or handle anything that may be evidence - damage the scene in overhauling and cleaning up when a fire is suspicious - open drawers or search to determine the absence of valuables - offer public statements as to suspicions of any kind - attempt to act as investigators, but give their ideas to the investigators when they arrive

Question 31

Physical Evidence in Auto Fires

Answer 31

- the fire scene - Footprints - tire tracks - location of container - unburned matchsticks in the motor compartment - missing lug bolts - unburned tire pads - removal of scented soil from the fire scene - seat and lazy back springs - loss of temper - location of gas tank drain plug - missing gas tank cap - missing vital engine accessories - fuel systems and electrical systems - finding of ignition key in debris - finding of remains of contents claimed in car by owner