Vehicle fires

Question 1

Are there more vehicle fires now or more deaths now?

Answer 1

Neither! Vehicle fires and vehicle fire deaths have steadily been decreasing, but hazards to firefighters have been increasing.

Question 2

Modern automobile hazards

Answer 2

a. Plastic components
b. Energy absorbing bumpers
c. Suspension systems
d. Safety/restraint systems
e. Fuel systems
f. Hybrid vehicles
g. Electrical systems
h. Drive lines
i. Wheels and tires
j. Cast aluminum/alloys
k. Magnesium
l. Human stupidity

Question 3

Plastic components of vehicle fires

Answer 3

a. Most interiors are constructed of plastic, up to 95%
b. Increased use of plastics means increased intensity of burning
c. Greater BTU production. 750,000-2,000,000BTUs!!! Wear your PPE!!!
d. Mostly polyurethane
e. “Enduraflex” (hydrogen cyanide)
f. First used on the Pontiac Fiero but widely used now for exterior components
g. Under fire conditions, plastics produce
i. Carbon monoxide
ii. Hydrogen cyanide
iii. Hydrogen chloride

Question 4

Energy absorbing bumper facts

Answer 4

a. First produced in 1973, DOT requires them on all passenger cars 1974 to date
b. Original design was no threat to firefighters
c. Hydraulic piston design (current) can explode with deadly results

Question 5

Suspension system types

Answer 5

a. Standard “leaf spring and shock”
b. Iso-strut “MacPherson” (potential extreme threat)
c. Air Suspension (mostly commercial, no threat)
d. Owner modified-lifting/lowering

Question 6

Pressure vessel dangers

Answer 6

a. Any vessel that contains fluid, gas, or air
b. Bumpers, shocks, struts, drive shafts, tires, ac systems
c. Hatchback and hood struts
i. Hydraulic fluid filled piston (mini-shock absorber)
ii. Hoods and hatchbacks (SUVs, passenger cars, trucks)
iii. Explosion potential + flying shrapnel

Question 7

Safety restraint system (ie the air bag and why its dangerous)

Answer 7

i. Unexpected deployment
ii. Sodium azide
iii. Rapid cooling
iv. Interior mop up
v. Potentially lethal

Question 8

Air bag safety

Answer 8

i. Beware of undeployed bags
ii. Stay out of range of bags
iii. Disconnect batteries
iv. Cool the area
Do not assume that air bags will not deploy

Question 9

Sodium Azide dangers

Answer 9

i. Fatal if absorbed through skin
ii. Fatal if swallowed
iii. Causes respiratory, skin, and eye irritation and can cause CNS issues
iv. Used to inflate air bags in automobiles
v. People often complain of skin, tracheal, and eye irritation
vi. NFPA rating: Health 4, Fire 1, Reactivity 3

Question 10

Types of fuels

Answer 10

gasoline/diesel
propane
ethanol/menthanol
compressed/liquid natural gas (CNG/LNG)
multiple batteries for hybrids
hydrogen

Question 11

Gasoline fuel

Answer 11

i. Gasoline in its liquid state does not burn
ii. Vapor density is 3-4 times heavier than air
iii. Specific gravity is 0.8
iv. Flash point is -45F
v. Auto ignition temp 536F
vi. One gallon of gas = 85lbs of nitroglycerin = 54lbs of dynamite
=

Question 12

Propane as fuel

Answer 12

i. Vapor density of 1.6
ii. LEL-UEL 2.1-9.5%
iii. BLEVE potential – expands 270 of its volume out of container

Question 13

CNG/LNG

Answer 13

i. Mostly methane
ii. LEL-UEL 5-15%
iii. Vapor density .6
iv. Disperses easily
v. Stored at 2400-4000PSI
vi. Dispensed to vehicle at same PSI

Question 14

Hydrogen

Answer 14

i. LEL-UEL 4-75%
ii. Vapor density .089
iii. Disperse easily
iv. Stored at 5000-10000PSI
v. Dispersed to vehicle at same PSI

Question 15

Traditional fuel tanks

Answer 15

a. Traditional lightweight metal tanks
i. Capacity of 10-40gallons
ii. “New” high density polyethylene plastic
iii. Potential for rapid release of product
iv. Campers, motor homes, and “lunch wagons” can have different fuels, tanks, and storage items

Question 16

What other parts are there in fuel systems

Answer 16

electric fuel pumps
battery connections
closed fuel systems
alternate fuel systems

Question 17

Alternate fuel systems

Answer 17

i. Propane tanks are constructed of steel
ii. CNG tanks are steel, aluminum, fiberglass (like SCBA bottles)
iii. Have pressure relief mechanisms to prevent catastrophic failure
iv. CNG vehicles have two manual shut offs
v. Hydrogen-carbon fire epoxy resin

Question 18

Exhaust systems

Answer 18

a. Catalytic converters
i. Normal operating temperatures around 1000F
ii. Malfunctioning can reach 2500F

Question 19

Drive lines

Answer 19

a. Potential explosion hazard
b. Front wheel drive
c. Vehicle position

Question 20

Wheels

Answer 20

a. Split rims can be deadly

b. Normal tires will scare you but not normally deadly

Question 21

Batteries

Answer 21

a. Sulfuric acid
b. Explosion potential
c. Dual batteries (RVs, 4WDs, Diesels)
d. “Maintenance Free” batteries
e. Electric vehicles
f. Disconnect negative cable first

Question 22

Contents of vehicles

Answer 22

a. Anything and everything
b. Look for placards/labels
c. Business name may give idea
d. Color of smoke
e. Don’t be afraid to ask for HAZMAT

Question 23

Approaching a vehicle on fire, you should observe:

Answer 23

i. Color of smoke
ii. Color of flames/fire
iii. Location of fire
iv. What the fire is impinging on
v. Exposures

Question 24

Tools and equipment needed for vehicle fires

Answer 24

i. 1.75in hoseline
ii. The irons
iii. Pry bar
iv. Dry chemical extinguisher (for magnesium)
v. Hand tools or cutters
vi. Flash light
vii. Wheel chocks

Question 25

How to approach a vehicle fire

Answer 25

i. When possible, approach the vehicle at a 45 degree angle to the front/rear of the car
ii. If you must approach directly in front or back, keep in mind the bumpers, hatchback and hood struts might explode.
iii. Tires likely to explode
iv. Fire apparatus should be placed at least 75ft from vehicle fires

Question 26

Fire cause investigations

Answer 26

a. There are many causes of vehicle fires. It is important that firefighters learn to recognize suspicious fires
b. Preserve evidence
c. Area of origin
d. Presence of accelerants
e. Don’t be Evidence Eradication Personnel