Reading Smoke

Question 1

Where did this reading smoke class come from?

Answer 1

This class adapted from: “The Art of Reading Smoke” by Dave Dodson (Retired Battalion Chief) and “Reading Smoke” by Gary Ells (Battalion Chief)

Question 2

Why do we read smoke?

Answer 2

• To help determine what we have
• To help determine where it’s at
• To help us predict where it is going
• To help us predict what is going to happen
• To help us better plan to deal with it

Question 3

Evaluating smoke allows us to determine and plan for:

Answer 3

o Size and extent of the incident
o Speed and direction of fire spread
o Degree of heat release and stage of the fire
o Possible adverse fire events
o Appropriate prioritization of strategies and tactics

Question 4

What is smoke?

Answer 4

a. The visible vapor and gases given off by a burning or smoldering substance, esp. the gray, brown, or blackish mixture or gases and suspended carbon particles resulting from combustion of wood, peat, coal or other organic matter

Question 5

Smoke Composition

Answer 5

a. Gases
b. Aerosols
c. Particulates
d. The bottom line is SMOKE is unburned fuel

Question 6

What has changed with fuels mass?

Answer 6

i. Today’s structures exhibit materials with considerably less mass than yesterday’s
1. This is due to the increased use of engineered materials such as trusses
2. In terms of a structure fire….MASS = TIME

Question 7

What has changed with fuels composition?

Answer 7

i. More synthetic materials such as plastics
ii. Plastics put off twice the BTU’s as normal Class A fuels
iii. Plastics also produce thick black clouds of smoke with more flammable gases than normal Class A fuels
iv. This means….More heat within the structure and more flammable smoke

Question 8

What has changed with regards to structures?

Answer 8

i. More synthetic materials such as plastics
ii. Plastics put off twice the BTU’s as normal Class A fuels
iii. Plastics also produce thick black clouds of smoke with more flammable gases than normal Class A fuels
iv. This means….More heat within the structure and more flammable smoke

Question 9

What has changed with regards to our equipment?

Answer 9

i. Better turnouts than in the past
ii. Use of SCBA is prevalent
iii. Faster notification systems leading to faster response times
iv. Equipment changes allow us…
1. To go farther into, and stay longer in hotter environments
2. To arrive on-scene prior to flashover
e. It all adds up to an increased exposure to extreme fire behavior events for today’s firefighters
f. The ability to read the smoke will allow us to avoid these events and deal with them safely

Question 10

Smoke as fuel

Answer 10

a. Smoke has trigger points
i. Flash point
ii. Fire point
iii. Ignition temp
b. How does Flammable range factor in?

Question 11

Predicting fire events

Answer 11

a. Need to be able to determine…
i. What stage the fire is in
ii. Is the “box” absorbing heat
1. Laminar vs. Turbulent smoke flow
b. What fire events do we want to predict
i. Flashover
ii. Backdraft
iii. Smoke explosion
iv. Rapid fire spread

Question 12

Reading smoke definition of flashover and warning signs

Answer 12

Transition between the growth and fully developed fire stages

i. Interior warning signs:
1. Heavy interior smoke conditions
2. Rollover occurring
3. High heat banking down suddenly
ii. Exterior warning signs:
1. Heavy, Dark, Turbulent smoke exiting
2. Auto ignition in the exiting smoke column
3. Advanced stage of burning

Question 13

Reading smoke definition of backdraft and warning signs

Answer 13

An explosion caused by the sudden introduction of oxygen to a smoldering oxygen deprived fire

i. Warning Signs
1. Yellowish-grey smoke
2. Whistling
3. Bowing windows
4. Sealed container
5. Pressurized smoke form small cracks
6. Little or no visible flame from exterior
7. Smoke stained, crazed windows

Question 14

Smoke explosions

Answer 14

Explosion in adjoining compartments where the smoke is below ignition temperature

i. Warning Signs:
1. Large amounts of relatively cool smoke in rooms or areas adjacent to the fire room
a. Upstairs from fire?
2. Growing fire
3. Increasing smoke density
4. Air intake overtaking smoke exiting

Question 15

Reading smoke rapid fire spread

Answer 15

i. Usually “Container” influenced
1. Look for fast moving smoke in high pressure zones (stairs and hallways)
ii. Fuel for spread is smoke driven vs. contents surface flaming

Question 16

Putting it (reading smoke) all together

Answer 16

a. Read it
b. Predict it
c. Reading the smoke and other factors to predict what is happening or going to happen is…
i. A four step process

1: evaluate the smoke
2: weigh all the factors
3: judge the rate of change
4: predict the event

Question 17

What are we evaluating in smoke?

Answer 17

i. Volume
ii. Velocity (Pressure)
iii. Density
iv. Color
v. Volume

Question 18

Volume of smoke

Answer 18

1. The amount of smoke visible
   a. Relative to the “box”
   b. Tells us how much fuel has off-gassed
   c. Typically described as light or heavy

Question 19

Velocity of smoke

Answer 19

1. The speed of the smoke exiting
   a. Velocity of the smoke leaving the building is indicative of the amount of pressure within the building
   b. Indicates either volume or heat
   c. Helps us locate the actual fire

Question 20

Rule of thumb regarding smoke

Answer 20

The hotter the fire, the faster and more turbulent the smoke

Question 21

Density of smoke

Answer 21

1. How thick the smoke is
   a. This is the most important factor
   b. Changes in density can indicate sudden change in conditions or spread of fire to other areas
   c. Quality of burning
   d. Chances of an adverse event
2. Density tells us how bad things are going to be

Question 22

Color of smoke

Answer 22

1. Off-white through dense black
   a. Odd colors may indicate hazmats
2. Tells us the stage of heating
3. Helps us determine location of fire

Question 23

What would an incipient fire look like?

Answer 23

1. Volume: Light
2. Velocity: Lazy and slow
3. Density: Thin and transparent to translucent
4. Color: Off white to gray

Question 24

What would an pre-flashover fire look like?

Answer 24

1. Volume: Heavy
2. Velocity: Moderate speed and very turbulent
3. Density: Very opaque
4. Color: Dark gray to black

Question 25

What would an air controlled fire look like?

Answer 25

1. Volume: Heavy
2. Velocity: Moderate speed and heavy turbulence
3. Density: Opaque to very opaque
4. Color: Dark grey, Brown, Yellowish

Question 26

What would an high-back-draft potential fire look like?

Answer 26

1. Volume: Large amount of light smoke, no smoke, puffing out of cracks
2. Velocity: Puffing
3. Density: Translucent to opaque
4. Color: Light grey to grey, Yellowish grey

Question 27

What would a freeburning (fuel fed) fire look like?

Answer 27

1. Volume: Heavy
2. Velocity: Rapid and turbulent
3. Density: Translucent to opaque
4. Color: Grey to dark grey

Question 28

Reading smoke step 2: weighing the factors

Answer 28

i. Container
ii. Thermal balance
iii. Weather
iv. Firefighting efforts and effect

Question 29

Reading smoke step 3: judge the rate of change

Answer 29

How fast are the smoke conditions getting better or worse?

Question 30

Reading smoke step 4: predict the event

Answer 30

i. One hostile event can lead to another
ii. Communicate your observations
iii. Warning signs are not always visual…trust your instincts

Question 31

What is the most important factor to look for in the smoke?

Answer 31

Density

Question 32

Tips to reading smoke (11 of them)

Answer 32

a. Sealed buildings “Filter” the smoke
b. Prior to entering, allow smoke to exit for a few seconds—determine if it looks the same?
i. Determine if your opening is going to cause an event and let it happen without you inside—It’s called burping the building
c. The higher the hydrocarbon content of the fuel
i. More energy (BTU’s) released
ii. Higher temperature
iii. Greater expansion and pressure created
d. Hot smoke moves faster near the seat of the fire
i. You can hold your hand light vertical to observe this
e. Grey-Black smoke with velocity and turbulence suddenly clearing
i. Flashover in seconds
f. Dense black smoke
i. Flammable liquids, plastics or hydrocarbons saturated materials
g. Dirty white-grey smoke, virtually no pressure, smoke hangs in the air
i. Mattress fire or food on the stove likely
h. Large volume of white smoke and no heat, smoke is translucent or transparent
i. Void space fire
i. Operating sprinklers show grey smoke outside with cool, dense smoke inside
i. Prime for smoke explosion
j. Fires in unventilated void spaces will backdraft or have a smoke explosion
i. Recognize and address voids early
1. The bigger the void space the more dangerous
2. Knee walls, bowstring truss attics, etc.
k. When dealing with these void spaces, either ventilate them vertically or apply water prior to opening
i. Piercing nozzles or small access hole for nozzle

Or just use an “Attic Sticker” [patent pending for TerrazasTech]