The Art of Reading Smoke

THE ART OF READING SMOKE Student Handout Developed by: Captain Rob Backer Lead Instructor, First Due Intelligence, LLC [email protected]

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The Art of Reading Smoke

Fighting fires in the year 2018 and beyond will be unlike the fires we fought in the 1990s and 2000s. Composites, lightweight construction, engineered structures, and unusual fuels will cause hostile fires to burn hotter, faster, and less predictably.

As a fire officer—or firefighter—you MUST be able to predict fire behavior and hostile fire events. If you don’t or can’t, firefighters will die or be critically injured. The key to predicting fire behavior is directly related to your ability to READ SMOKE as you arrive and begin firefighting operations.

This class will help you rediscover the ART of READING SMOKE!

Why do we read smoke?

Reading smoke helps you discover the specific location and intensity of a fire, building collapse potential, and the likelihood of a hostile fire event such as flashover. If you can discover these things, you can make better strategic and tactical decisions! In order to read smoke, you must have a foundation in some basics.

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The Art of Reading Smoke

First, you must know the Advanced Basics:

Concept #1: Smoke is FUEL! Firefighters use the term “smoke” when addressing the solids, aerosols, and gases being produced by incomplete burning or heat degradation of contents.

1. Smoke Solids • 70% of smoke is particulate (mostly carbon) • Carbon (soot) is black • Ash is dirty white (minerals and metals that carry heat) • Particulates can cause a fire in a box to go vent-restricted

2. Smoke Aerosols • Water: clean white when visible • Hydrocarbons: black oily mist/droplets • Oil droplets can have a self-ignition temperature as low as 460°F

3. Smoke Gases • Thousands of gas types in smoke • Most are transient and trace • Typical gases that impact fire behavior are carbon monoxide, hydrogen cyanide, benzene, and acrolein • See chart (next page) for properties • “Ladder fuels” • Gases also create “continuity of fuel” throughout box

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The Art of Reading Smoke

Properties of Gases Typically Found in Smoke

Gas Flashpoint Self- Flammable Notes Ignition Range in Temp. Air Carbon See notes 1,128ºF 12%–74% CO is considered a gas Monoxide only and, therefore, (CO) doesn’t have flashpoint. The flammable range of CO is 12%–74% only at the ignition temperature. The flammable range of CO decreases below its ignition temperature. Hydrogen 0°F 1,000°F 5%–40% HCN is produced when Cyanide high temperatures break (HCN) down nitrogen-containing products. HCN is quite flammable and is considered extremely toxic. Benzene 12°F 928°F 1%–8% Most plastics release (C6H6) benzene while burning. Benzene is also a common product from the burning of fuel oils. Acrolein –15°F 450°F 3%–31% Acrolein is a by-product of (C3H4O) the incomplete combustion of wood, wood products, and other cellulosic materials. Poly- plastics can also render acrolein. Source: http://www.cdc.gov/niosh/npg/npg.html.

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The Art of Reading Smoke

Concept #2: The fuels have changed: The contents and structural elements being heated or burned are of lower mass than previous decades. These materials are also more synthetic than ever. These changes have created fire behavior that grows faster, and to a higher intensity, than ever before seen. Firefighters must be prepared to fight fires that are already vent-limited, and at or past the point for flashover, BEFORE their arrival.

Concept #3: The fuels have trigger points: There are “triggers” for hostile fire events: These triggers are simply “right temperature” and “right mixture.” Flash point can trigger a smoke explosion. Fire point triggers rapid fire spread. Ignition temperature triggers auto ignition, backdraft, and flashover.

Flash Point: The lowest temperature a fuel will off-gas an ignitable mixture that will simply flash—but not sustain, given a spark or flame.

Fire Point: The lowest temperature a fuel will off-gas an ignitable mixture that will ignite and continue to burn given a spark or flame.

Ignition Temperature: The lowest temperature a fuel will off-gas an ignitable mixture that can self-ignite.

Burnable gases must be in their right percentage with air to ignite. In hostile fires, a gas may be hot enough to self-ignite—but is too rich to burn. Firefighters’ efforts can cause this ignition.

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The Art of Reading Smoke

Old School Fire Graph Today’s Fire Graph

Today’s compartment fire has six phases: Ignition, first growth, vent- restricted, explosive growth, fully developed, and decay.

Smoke is the real enemy:

Can you tell what “phase” the fire is in? (The vent-restricted phase is the most dangerous.)

Tell if the “box” is absorbing heat or not. The MOST important smoke observation to make on arrival is the smoke-flow characteristic:

“Turbulent vs. Laminar” flow

Turbulent = flashover Laminar = box is still absorbing

DON’T CRAWL INTO TURBULENT SMOKE!

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The Art of Reading Smoke

SOME “OVERHEAD” RULES FOR “READING SMOKE”:

The Process:

1. Nothing is absolute

2. Where is there smoke? Where isn’t there smoke? What is the size of the exhaust opening?

3. Capturing “rate of change” is mandatory—is it getting better or worse in seconds or minutes? Remember: a fire can grow 200 times its volume in two seconds in today’s fires!

Barriers to Reading Smoke:

• Flame focus (your eyes and your mind) • Light vs. heavy mentality • Fixation on one presentation – you must inventory all the smoke from every opening • Weather – Weather conditions (wind, temperature, precipitation) can alter the appearance of the smoke attributes.

Overcoming the barriers: • Practice, practice, practice! • Keep the conversation going! Reach out for help, answers to questions, or to host a class ▪ Twitter @firstdueintel ▪ Instagram first_due_intelligence ▪ Facebook Rob Backer and First Due Intelligence ▪ Email [email protected]

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The Art of Reading Smoke

The 3-STEP process to READING SMOKE:

STEP 1: INVENTORY the KEY ATTRIBUTES of smoke:

Volume = Amount of fuel off-gassing. It helps you understand relativity to the box and sets an impression for everything else. A small volume of smoke from more than one opening of a LARGE building is significant.

Velocity (How fast is the smoke leaving?) = Indicates pressure build-up. Only volume and heat can cause pressure. Volume- caused pressure will immediately slow down; heat-caused pressure slows gradually. Turbulent smoke is heat-caused. Comparing velocities help you determine WHERE the actual fire is. Look for the fastest smoke from the most resistive opening.

Density = Quality of burning, potential for event. The thicker the smoke, the more dangerous it is. Zero-visibility smoke has fuel continuity to the fire and can ignite with no warning to those within it. Zero-visibility smoke with velocity is amazingly dangerous!

Color = Indicates the stage of heating and distance to fire. As a starting place, white is cooler, black is hotter. Carbon and hydrocarbons are STICKY and can be FILTERED—taking away blackness as smoke travels over distance or through cracks. White smoke should not be discarded! Dirty white smoke with velocity means a hot fire, but the smoke you see has traveled some distance or has been filtered. Thin, black smoke means “flame pushed.” Brown smoke means unfinished wood is being heated.

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The Art of Reading Smoke

STEP 2: WHAT is INFLUENCING THE KEY ATTRIBUTES?

• Container: can change the meaning of volume, velocity, density, and color.

• Weather: hot/humid gives a narrow, defined column; hot/dry gives a cone shaped column; cold/humid causes the smoke to crash and hangout near; cold/dry causes the smoke to crash but disperse easily. Below-freezing air temperatures can make black smoke look white within a few feet of the outside vent opening (moisture content of smoke condensing).

STEP 3: Determine the Rate of Change—Answer the Questions

Getting better or getting worse? Seconds or minutes? (Not the flames—the smoke conditions!)

You should now know: • The exact location of the fire • The size of the fire • The potential for a hostile fire event and the rate of change

Remember to communicate key observations and trust your instincts—if something doesn’t look right, it probably isn’t!

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The Art of Reading Smoke

Reading Smoke Shortcuts

What You See What It Can Mean

Turbulent smoke Warning sign of impending flashover that fills a box Thick, black, fast Close to the seat of the fire, super hot smoke capable of instant ignition, maybe a vent-limited fire that needs air Thin, black, fast Flame-pushed smoke; fire nearby that is well ventilated Dirty white smoke Heat-pushed smoke that has traveled a distance or with velocity has had the carbon/hydrocarbon filtered (like smoke through a crack) Same color Deep-seated fire, possibly located well within a (white/gray) and building or in combustible voids and concealed same velocity from spaces multiple openings Low-volume white Serious fire deep within smoke from more than one location of a large box Brown smoke Unfinished wood reaching late heating (can support flame); usually a sign that a contents fire is transitioning into a structural fire; when coming from structural spaces of lightweight wood structures, a warning sign of collapse! Yellowish-gray Sulfur compounds = warning sign of impending smoke from cracks backdraft or seams

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The Art of Reading Smoke

When you read smoke, you are basically trying to ascertain: • The EXACT location of the fire • The SIZE of the fire • The PATH/SPEED of fire spread • The likelihood of a HOSTILE FIRE EVENT

For the scenarios, try to answer these questions in your group: • Specifically where is the fire? • How big or intense is the fire? • What’s next? (Where is the fire going and how fast? Be specific.) • Best tactic:

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The Art of Reading Smoke

Remember:

 With fewer fires, the Art of Reading Smoke could be lost . . . at the expense of our lives.

 Practice doesn’t make perfect, PERFECT practice makes perfect!

 Don’t be ARBITRARILY AGGRESSIVE—be INTELLECTUALLY AGGRESSIVE!

 PASS ON THIS INFORMATION!

Call or email me if you want more info or have questions: Rob Backer 720-937-0144 [email protected]

Special THANKS to: Dave Dodson – Battalion Chief (ret.) Loveland, CO Fire

Study fire behavior! Start with the NIST technical reports of significant recent fire events @ www.fire.nist.gov.

Dave Dodson’s Reading Smoke Training DVD and Reading Smoke—The Practice Sessions are available for sale at www.fireengineeringbooks.com.

Don’t Just Be SAFE—Go Out and Make It SAFE!

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