Posts Tagged ‘FBI’

Air track includes factors related to the movement of smoke out of the compartment or building and the movement of air into the fire. Air track is caused by pressure differentials inside and outside the compartment and by gravity current (differences in density between the hot smoke and cooler air). Air track indicators include velocity, turbulence, direction, and movement of the hot gas layer.

My prior post, Reading the Fire: Air Track Indicators began the process of developing or refining an existing concept map of air track indicators. It is important to evaluate air track at openings and on the interior of the structure. As a starting point, I have identified direction, velocity & flow, and wind as basic air track indicator categories (see Figure 1). However, you may choose to approach this somewhat differently.

Figure 1. Basic Air Track Indicators

Air track indicators provide critical cues related to stages of fire development, burning regime, and potential for fire spread. However, it is essential that assessment of air track be integrated with other categories of indicators in the B-SAHF scheme to gain a clearer sense of fire conditions and likely fire behavior. Remember that looking at air track alone may be misleading.

Air Track at Openings and on the Interior

Discharge of smoke at openings and potential openings (Building Factors) is likely the most obvious indicator of air track while lack of smoke discharge may be a less obvious, but potentially important sign of inward movement of air.

Observation and interpretation of smoke and air movement at openings is an essential part of air track assessment, but it must not stop there. Movement of smoke and air on the interior can also provide important information regarding fire behavior.

The path taken by the air track will define the direction of fire spread and may present a significant hazard to firefighters operating between inlet and exhaust openings. This necessitates ongoing assessment of air track from both the exterior and interior of the building.

Figure 2. Air Track

Direction

Consider the following observations. You arrive at a fire in a commercial building and observe smoke showing from a door on floor 1 (Figure 2).

The smoke discharge fills the upper half of the door while it appears that air is moving in the bottom half of the door. What can you infer from this? What would you infer if the smoke discharge completely filled the door?

The direction of the air track can also provide valuable cues to fire behavior. When air moves in an opening (inlet) without any smoke discharge, it is likely that smoke is exiting from another opening (exhaust). When this condition is reversed, and smoke comes out with not inward movement of air, it is likely that another opening is serving as an inlet. When the air track is bi-directional and air moves in at the bottom and smoke moves out at the top, this may be the only opening in the compartment or ventilation from other exhaust openings may be inadequate. In any case where smoke is discharging through an opening, the fire is likely moving in that direction.

Mixing of smoke and air occurs at the interface between the hot gas layer and cooler air below. This is a critical factor in creating the conditions required for backdraft and many types of fire gas ignitions. Pulsing air track, outward movement of smoke followed by an inward movement of air is indicative of an underventlated fire and potential backdraft conditions (consider other indicators in determining if backdraft conditions are likely to exist). It is critical to remember that these pulsations can vary in duration and that backdraft does not generally occur immediately upon making an opening. The time between making an opening and occurrence of a backdraft is dependent on many factors including distance of the compartment with backdraft conditions from the opening. Air track is an extremely useful indicator, but it must be integrated with a big picture evaluation of fire behavior indicators.

Location of inlet and exhaust openings (particularly if they are on different levels or if impacted by wind) is an important Building Factor that directly impacts air track. This is an excellent example of why each of the categories of fire behavior indicators (FBI) must be considered together when reading the fire.

Velocity & Flow

Velocity and flow are two interrelated air track factors. Velocity refers to the speed of smoke and air movement. However, the speed with which smoke is traveling (either out of an opening in the compartment or building or within a compartment) must be considered in relation to the size of an opening or conduit. Flow may be either smooth (laminar) or turbulent. This is dependent to a large extent on velocity. High velocity generally results in turbulent flow through a compartment (such as a hallway) or out an opening (e.g., doorway or window). For a given volume, velocity and turbulence will be higher through smaller openings). High velocity smoke discharge and turbulent flow is generally indicative of high temperature within the compartment (another connection, in this case between air track and heat).

Wind

Wind can influence smoke movement on the exterior of a building (in some cases masking exterior air track indicators) or it can have a more direct influence on air track. As discussed in a number of earlier posts, wind can have a significant influence on compartment fire behavior.

• Wind Driven Fires
• NIST Wind Driven Fire Experiments: Establishing a Baseline
• NIST Wind Driven Fire Experiments: Anti-Ventilation Wind-Control Devices
• NIST Wind Driven Fire Experiments: Wind-Control Devices and Fire Suppression
• Wind Driven Fires: Tactical Problem

Understanding the potential influence of wind on fire behavior, provides a basis to read and interpret air track indicators. Wind exerts pressure on structural surfaces (see Figure 3), which under fire conditions can have a significant influence on movement of both smoke and air.

Figure 3. Distribution of Pressure due to Wind

Note. Adapted from Fire Ventilation (p. 34-35) by Stefan Svensson, 2000, Karlstad,Sweden: Räddnings Verket. Copyright 2000 by Stefan Svensson & Räddnings Verket.

Wind on an inlet opening can act much the same as a supercharger, dramatically increasing heat release rate, fire intensity, and rate of spread (see Figure 4).

Figure 4. Wind Effects

Movement of the Hot Gas Layer

Horizontal movement of the hot gas layer and turbulence at the interface between smoke and clear air below indicate air track direction. As discussed in Reading the Fire: Smoke Indicators height of the hot gas layer is a significant indicator of fire conditions. Even more important than the height of the hot gas layer, are changes in height. A sudden rise could indicate that ventilation has occurred (either performed by firefighters or caused by the fire). Gradual lowering of the hot gas layer could indicate worsening conditions and increased potential for flashover. However, inappropriate or excessive application of water can also cause lowering of the hot gas layer. Sudden lowering could indicate worsening conditions caused by flashover in an adjacent compartment. While not commonly known as a backdraft indicator, raising and lowing of the hot gas layer is similar to a pulsing air track observed at an opening (however in this case the compartment is not fully smoke logged, so the expanding and contracting gases cause the bottom of the hot gas layer to move up and down).

Height and more importantly vertical movement of the hot gas layer may be considered as Smoke or Air Track Indicators (a good argument can be made in either case). For now, I have chosen to position these two types of indicator under Smoke, but with linkage to Air Track, but I am considering moving them to Air Track (while maintaining linkage to Smoke Indicators).

Work in Progress

Hopefully we have been working on this project together and you have been developing or refining the air track segment of your fire behavior indicators concept map. My current map is illustrated in Figure 5.

Figure 5. Air Track Indicators Concept Map v5.2.2.1

You can also download a printer friendly version of the Air Track Indicators Concept Map v5.2.2.1 (including notes made during development). As indicated by the significant number of notes in the Staging Area of the printer friendly version, a bit more work remains to be done before integrating the Smoke and Air Track indicators in the complete version of the Fire Behavior Indicators Concept Map. Should you have any suggestions or feedback, please post a comment!

Ed Hartin, MS, EFO, MIFireE, CFO

References

Svensson, S. (2000). Fire ventilation. Karlstad, Sweden: Räddnings Verket.

In Reading the Fire: How to Improve Your Skills, I discussed building a concept map fire of behavior indicators as a method to increase competence in reading the fire. Construction of a concept map increases awareness of key indicators and understanding their interrelationships. I am working through this process along with you, with the latest revision to my concept map. Thus far, I have examined Building Factors and Smoke Indicators; the first two categories in the B-SAHF (Building, Smoke, Air Track, Heat, and Flame) organizing scheme. For review of the discussion of building factors and smoke indicators see the following Reading the Fire posts:

• Building Factors
• Building Factors Part 2
• Building Factors Part 3
• Smoke Indicators
• Smoke Indicators Part 2

Focus Question

Developing a concept map starts with a focus question that specifies the problem or issue that the map is intended to help resolve. Developing or refining a concept map identifying fire behavior indicators (FBI) and their interrelationships starts with the following focus question:

What building, smoke, air track, heat, and flame indicators
provide clues to current and potential fire behavior?

As you work through this process it is likely that you will uncover additional concepts that may be added to the Building Factors or Smoke Indicators concept maps. You may also identify interrelationships that you may not have thought of previously. Don’t forget to go back and capture these thoughts as you work on the air track map.

Air Track

In Reading the Fire: Smoke Indicators, I defined the difference between Smoke and Air Track indicators. However, it may be useful to revisit the difference between these two categories before engaging in a detailed look at Air Track indicators.

Smoke: What does the smoke look like and where is it coming from? This indicator can be extremely useful in determining the location and extent of the fire. Smoke indicators may be visible on the exterior as well as inside the building. Don’t forget that size-up and dynamic risk assessment must continue after you have made entry!

Air Track: Related to smoke, air track is the movement of both smoke (generally out from the fire area) and air (generally in towards the fire area). Observation of air track starts from the exterior but becomes more critical when making entry. What does the air track look like at the door? Air track continues to be significant when you are working on the interior.

While these two sets of indicators are interrelated, they are considered separately as air track relates to movement of both smoke and air.

Getting Started

When reading the fire it is important not to focus on a single indicator or category of indicators. However, Air Track indicators often provide critical information about stages of fire development, burning regime, differences in conditions throughout the building, and direction of fire spread.

As always in developing a concept map it is important to move from general concepts to those that are more specific. Air Track must be considered at openings and inside the building. Basic indicators include direction, velocity & flow, and wind (as a major influence or modifying factor) as illustrated in Figure 1. However, you may choose to approach this somewhat differently.

Figure 1. Basic Air Track Indicators

Developing the Detail

Expanding the map requires identification of additional detail for each of the fundamental concepts. If an idea appears to be obviously related to one of the concepts already on the map, go ahead and add it. If you are unsure of where it might go, but it seems important, list it off to the side in a staging area for possible additions. Download a printer friendly version of Air Track Indicators to use as a starting point for this process.

Next Steps

Remember that the process of contracting your own map is likely as important as the (never quite) finished product. The following steps may help you expand and refine the Air Track indicators segment of the map:

• Look at each of the subcategories individually and brainstorm additional detail. This works best if you collaborate with others.
• Have a look at the following video clip using your partially completed map and notes as a guide to identifying important Air Track indicators. Think about what the Air Track indicators mean and visualize developing fire conditions inside the building.

The following video has some excellent Air Track indicators that may aid in developing and refining your Smoke Indicators concept map.

It may also be useful to go back and look at the video from Reading the Fire: Building Factors Part 2 or Reading the Fire: Smoke Indicators and focus in on Air Track Indicators.

Step Back and Look at the Entire Picture

Take this opportunity to engage with the rest of the B-SAHF indicators. Download and print the B-SAHF Worksheet. Consider the information provided in each of the short video clips and complete the worksheet for each. First, describe what you observe in terms of the Building, Smoke, Air Track, Heat, and Flame Indicators and then answer the following five standard questions?

1. What additional information would you like to have? How could you obtain it?
2. What stage(s) of development is the fire likely to be in (incipient, growth, fully developed, or decay)?
3. What burning regime is the fire in (fuel controlled or ventilation controlled)?
4. What conditions would you expect to find inside this building?
5. How would you expect the fire to develop over the next two to three minutes?

Twitter

While I believe that Twitter has tremendous potential for quickly sharing information and building a community of practice, the plug-in that I have been using to integrate Twitter with the CFBT-US Blog has resulted in posts being cluttered with a tremendous amount of spam. I have disabled the plug-in, but will continue to provide updates on breaking news and information via Twitter. Follow edhartin on Twitter!

Ed Hartin, MS, EFO, MIFireE, CFO

In many cases, smoke may provide the dominant indication that there is a fire in the building (but keep in mind that if you can see smoke on the exterior, there are also air track indicators). Have a look at Figure 1 and see what smoke indicators you observe.

Figure 1. Smoke Indicators

Note: Terry Moody Photo, Commercial Fire Ranlo, NC.

My prior post, Reading the Fire: Smoke Indicators began the process of developing or refining an existing concept map of smoke indicators. As a starting point, I have identified location, optical density (thickness), color, physical density (buoyancy), and volume as basic categories of smoke indicators (see Figure 2). However, you may choose to approach this somewhat differently.

Figure 2. Basic Categories of Smoke Indicators

These five categories provide a simple framework for examining smoke indicators, but considerably more detail may be developed within each category. Observation of smoke indicators can often provide an indication of the location and extent of the fire as well as its burning regime. However, it is essential that smoke indicators be integrated with other categories of indicators in the B-SAHF scheme to gain a clearer sense of fire conditions and likely fire behavior. Remember that looking at smoke alone may be misleading.

Location

The concept of smoke location applies to both the exterior and interior of the structure. From the exterior, consider the following:

• Is smoke visible (this one is simple)?
• What side(s) and level(s) of the building is the smoke visible from?
• Is the smoke discharge from substantial openings such as open windows or doors?
• Is smoke discharge limited to a single opening or is it visible from multiple openings?
• Is the smoke discharge from points of normal building leakage (e.g., gaps around windows and doors, normal ventilation openings such as attic vents)?
• Does the location of smoke discharge change over time?

These questions identify potential linkage to building factors indicators (i.e., actual openings) and air track (discharge of smoke and intake of air). Location may also be interrelated with other smoke indicators such as volume. For example, discharge of smoke from the top of a doorway has considerably different implications if the ceiling height is 7.3 m (24′) rather than 2.4 m (8′).

• Smoke location continues to be important on the interior of the building.
• Is smoke confined to a single compartment or group of compartments?
• Is smoke present in void spaces?
• Is smoke on one level or multiple levels?
• Are there changes to the location of smoke over time?

Some indicators can be classified into more than one category. For example, smoke at the ceiling level could be considered from the perspective of location or (potentially more importantly) as an indicator of volume.

Volume

The language used to describe fire and smoke conditions in radio communications (e.g, size-up report or report on conditions) is often subjective and ambiguous. For example, what exactly is heavy smoke and how is that different from light smoke. I gained a new appreciation of the ambiguity of these terms when teaching fire officers who had English as a second or third language. Heavy and light commonly refer to weight, but in this case are frequently applied to volume or possibly optical density (or in other cases both of these characteristics). In an effort to provide clarity, I use the terms large and small in relation to volume. Note that this is still subjective, but I think a bit clearer than heavy and light.

From the exterior, consider the volume of smoke discharged. However, it is important to keep in mind that this may not be an indication of how much smoke is in the building. Volume becomes a bit more complex, but more important inside the building. The level of the neutral pressure plane at openings is related to both volume and air track. After entering a compartment, the level of the hot gas layer is a key indicator of smoke volume, but it must be considered in relation to building factor such as ceiling height. Firefighters often consider the height of the hot gas layer above the floor, but may not consider the depth of the hot gas layer down from the ceiling (which is equally important as an indicator of smoke volume). Compartments that are completely filled with smoke are said to be smoke logged. As with other indicators, it is essential to consider changes over time. In particular:

• Is the volume of smoke discharged from the exterior increasing or decreasing?
• Is the level of the neutral plane or hot gas layer raising or lowering?

Movement of the hot gas layer can indicate changes in volume or air track, both of which are important indicators of changing fire conditions, burning regime, and potential for extreme fire behavior such as ventilation induced flashover or backdraft.

Optical Density (Thickness)

As with the earlier discussion of heavy and light smoke, density can be a bit confusing as it is used in two different contexts. Most commonly, dense smoke is so thick that you can’t easily see through it. Optical density refers to obscuration, how difficult it is to see through the smoke. Thick or optically dense smoke contains a high concentration of particulates and is difficult to see through. High particulate concentration can also give the smoke the appearance of having texture (like velvet). Thickness is influenced by burning regime and the type of fuel that is burning. Ventilation controlled conditions and/or combustion of many synthetic fuels can result in development of optically dense or thick smoke.

• How thick is the smoke on the exterior of the structure?
• How thick is the smoke inside the building?
• Does thickness differ based on location (a potential connection with location indicators here)?
• Is thickness changing over time?

A key indicator substantively related to thickness is texture. Increased particulate concentration, increases obscuration, but if sufficiently high, also results in the appearance of texture. Smoke that looks like velvet is the result of extremely inefficient combustion and contains a high concentration of unburned fuel.

Color

Color has traditionally been an important but often misunderstood smoke indicator. Consider the following questions:

• Which color smoke indicates the greatest hazard to firefighters: Creamy white or light tan, light gray, dark gray, brown, or black?
• What color smoke indicates potential backdraft: White, yellow, brown, dark gray, or black?

The greatest challenge in making sense of smoke color is that it is the result of a number of interrelated factors including fuel type and burning regime. Light colored (e.g., white to light tan) smoke may contain a high concentration of unburned pyrolizate. While this smoke color is not typically associated with a high degree of hazard, this smoke is fuel and may present a significant threat. Yellowish smoke is typically associated with the backdraft phenomena. However, observation of a number of backdraft events points to considerably less certainty in the relationship between smoke color and backdraft.

Think about the range of smoke color that may be encountered in structural firefighting, but remember that all organic (carbon containing) fuel can produce black smoke under sufficiently ventilation controlled conditions.

Changes in color over time are a critical indicator of developing fire conditions and the effect of tactical operations.

In the early 1980s when my eldest daughter was five or six years old, she was observing live fire training in an acquired structure. During one evolution, she pointed out smoke conditions at a second floor window to a photographer who was taking pictures for a National Fire Protection Association (NFPA) training program. She stated “you see that light gray smoke coming from the window…it’s going to get black and then flames will come out”. Sure enough that was exactly what happened. The photographer was surprised. I was not. I pointed out that Heather had been to more fires than the photographer and that children pay attention to everything. There is a lesson here for us!

Physical Density (Buoyancy)

From a scientific perspective, density is mass per unit volume. Vapor density is the relative density of a gas or vapor in comparison to air (at standard temperature and pressure). The fire environment adds some complexity as increasing the temperature of a gas can cause it to expand, reducing its density (which is why hot smoke goes up). However, most of the constituents of smoke are heavier than air and will sink as they cool. Physical density refers to the buoyancy of the smoke.

Smoke that is buoyant will rise quickly and smoke that is not will hang low to the ground. Generally buoyancy is related to the temperature of the smoke, the higher the temperature, the less (physically) dense the smoke and the greater the buoyancy. Early in fire development smoke may not be that buoyant due to limited heat release. Development of a well defined hot gas layer indicates significant difference in temperature between the hot smoke and cooler air below. Later in the development of the fire, buoyancy may be affected by the operation of automatic sprinklers (or application of water from hoselines) or it may simply cool as it moves away from the fire. In evaluating the importance of physical density, consider the following questions:

• What building factors might impact on buoyancy?
• How does ambient temperature influence buoyancy?
• What potential hazards does smoke with limited buoyancy (i.e., cool smoke) present?

Work in Progress

Hopefully we have been working on this project together and you have been developing or refining the smoke segment of your fire behavior indicators concept map. My current map is illustrated in Figure 3.

Figure 3. Smoke Indicators Concept Map v5.2.2.1

You can also download a printer friendly version of the Smoke Indicators Concept Map v5.2.2.1 (including notes made during development). As always, feedback is greatly appreciated.

Ed Hartin, MS, EFO, MIFireE, CFO

As discussed in prior Reading the Fire posts and the ongoing series examining fire behavior indicators (FBI) using the B-SAHF (Building, Smoke, Air Track, Heat, and Flame) organizing scheme, developing proficiency requires practice. This post provides an opportunity to exercise your skills using three video segments shot during a commercial fire. In addition to practicing your skill in reading the fire, use these video clips to help develop or refine your smoke indicators concept map (see Reading the Fire: Smoke Indicators).

Commercial Fire

The Safety Harbor (FL) Fire Department responded to a commercial fire at Matrix Group Limited sporting goods warehouse and office building. First arriving crews initiated offensive operations but developing fire conditions required a shift to a defensive strategy. The 13,500 ft² (1,254 m²) warehouse was destroyed resulting in an estimated 1.5 million dollars in damage. One firefighter experienced a back injury during firefighting operations.

Download and print two copies of the B-SAHF Worksheet. Watch the first 60 seconds of Video Segment 1. Consider the information provided in this segment of the video clip. First, describe what you observe in terms of the Building, Smoke, Air Track, Heat, and Flame Indicators and then answer the following five standard questions?

1. What additional information would you like to have? How could you obtain it?
2. What stage(s) of development is the fire likely to be in (incipient, growth, fully developed, or decay)?
3. What burning regime is the fire in (fuel controlled or ventilation controlled)?
4. What conditions would you expect to find inside this building?
5. How would you expect the fire to develop over the next two to three minutes?

Video Segment 1

Give some thought to how building factors might be influencing fire behavior and the way in which other FBI might be presenting (see Reading the Fire: Building Factors Part 3), specifically:

What is the height of the building (and more importantly the interior compartments)? What is the likely impact on fire behavior and presentation of FBI?

1. What is the building construction classification? Does this have an impact?
2. This is a sporting goods warehouse and office occupancy. What type of contents (fuel ) would you anticipate (think about heat of combustion, heat release rate, mass of fuel, fuel geometry)?

Go back to Video Segment 1, examine conditions from 3:15 to 4:15, and consider the answers to the five standard questions on the B-SAHF worksheet.

1. How have conditions changed?
2. Would you change the answers to the five standard questions based on your current observations?

Watch the remainder of Video Segment 1 and continue your assessment of current conditions and fire behavior prediction.

1. How do conditions change?
2. What impact are tactical operations having on the fire? How does this influence the FBI?

Watch the first 1:30 of the Video Segment 2. Consider the information provided in this segment of the video clip. How have conditions changed from those observed at the start of Video Segment 1?

Using the second copy of the B-SAHF Worksheet, describe what you observe in terms of the Building, Smoke, Air Track, Heat, and Flame Indicators and then answer the following five standard questions?

1. What additional information would you like to have? How could you obtain it?
2. What stage(s) of development is the fire likely to be in (incipient, growth, fully developed, or decay)?
3. What burning regime is the fire in (fuel controlled or ventilation controlled)?
4. What conditions would you expect to find inside this building?
5. How would you expect the fire to develop over the next two to three minutes?

Video Segment 2

Watch the remainder of Video Segment 2 and continue your assessment of current conditions and fire behavior prediction.

1. How do conditions change?
2. What impact are tactical operations having on the fire? How does this influence the FBI?

What smoke indicators did you identify during these two B-SAHF exercises? Were these identified on your Smoke Indicators Concept Map? If not, take a minute to update the map (or place them in the staging area for future consideration).

Watch the last video segment and see if there are any other smoke indicators that you might want to add to the map.

Video Segment 3

Ed Hartin, MS, EFO, MIFireE, CFO

In Reading the Fire: How to Improve Your Skills, I discussed building a concept map of fire behavior indicators as a method to increase competence in reading the fire. Construction of a concept map increases awareness of key indicators and understanding their interrelationships. I am working through this process along with you, with the latest revision to my concept map. Thus far, I have examined Building Factors, the first category of indicators in the B-SAHF (Building, Smoke, Air Track, Heat, and Flame) organizing scheme. For review of the discussion of building factors and revision of this segment of my concept map see the following three posts:

Reading the Fire: Building Factors

Reading the Fire: Building Factors Part 2

Reading the Fire: Building Factors Part 3

Focus Question

As pointed out at the start of this project, a concept map starts with a focus question that specifies the problem or issue that the map is intended to help resolve. The fire behavior indicators (FBI) concept map starts with the following focus question:

What building, smoke, air track, heat, and flame indicators
provide clues to current and potential fire behavior?

It is important to remember that a concept map is never finished. After you develop the first draft, it is always necessary to revise the map to increase clarity or add important concepts that you discover as work continues.

In the next few posts in the series, we will apply this focus question to smoke indicators.

Smoke Versus Air Track

There are a number of interrelationships between Smoke and Air Track. However, in the B-SAHF organizing scheme they are considered separately. As we begin to develop or refine the map of Smoke Indicators it is useful to revisit the difference between these two categories in the B-SAHF scheme as outlined in Reading the Fire: Building Factors

Smoke: What does the smoke look like and where is it coming from? This indicator can be extremely useful in determining the location and extent of the fire. Smoke indicators may be visible on the exterior as well as inside the building. Don’t forget that size-up and dynamic risk assessment must continue after you have made entry!

Air Track: Related to smoke, air track is the movement of both smoke (generally out from the fire area) and air (generally in towards the fire area). Observation of air track starts from the exterior but becomes more critical when making entry. What does the air track look like at the door? Air track continues to be significant when you are working on the interior.

Getting Started

When reading the fire it is important not to focus on a single indicator or category of indicators. However, Smoke Indicators often provide critical information about stages of fire development, burning regime, and differences in conditions throughout the building.

As always in developing a concept map it is important to move from general concepts to those that are more specific. Basic smoke indicators may include location, optical density (thickness), color, physical density (buoyancy), and volume as illustrated in Figure 1. However, you may choose to approach this somewhat differently.

Figure 1. Basic Smoke Indicators

Developing the Detail

Expanding the map requires identification of additional detail for each of the fundamental concepts. If an idea appears to be obviously related to one of the concepts already on the map, go ahead and add it. If you are unsure of where it might go, but it seems important, list it off to the side in a staging area for possible additions. Download a printer friendly version of Smoke Indicators to use as a starting point for this process.

Next Steps

Remember that the process of contracting your own map is likely as important as the (never quite) finished product. The following steps may help you expand and refine the Smoke Indicators segment of the map:

• Look at each of the subcategories individually and brainstorm additional detail. This works best if you collaborate with others.
• Have a look at the following video clip using your partially completed map and notes as a guide to identifying important smoke indicators. Think about what the smoke indicators mean and visualize developing fire conditions inside the building.

The following video has some excellent smoke indicators towards the middle of the clip that may aid in developing and refining your Smoke Indicators concept map.

Step Back and Look at the Entire Picture

I would not want to waste the opportunity to engage with the rest of the B-SAHF indicators. Download and print the B-SAHF Worksheet. Consider the information provided in each of the short video clips and complete the worksheet for each. First, describe what you observe in terms of the Building, Smoke, Air Track, Heat, and Flame Indicators and then answer the following five standard questions?

1. What additional information would you like to have? How could you obtain it?
2. What stage(s) of development is the fire likely to be in (incipient, growth, fully developed, or decay)?
3. What burning regime is the fire in (fuel controlled or ventilation controlled)?
4. What conditions would you expect to find inside this building?
5. How would you expect the fire to develop over the next two to three minutes

Twitter

While I did not get any response from the questions I posted on Twitter related to Building Factors, I will continue this practice as we explore smoke indicators. Have a look [http://twitter.com/edhartin] and join in by responding to the questions. End your comments related to Fire Behavior Indicators on Twitter with #B-SAHF (this hashtag simplifies searching for FBI related posts). In addition to B-SAHF questions, I also post links to video clips and fire behavior related new items on Twitter.

Ed Hartin, MS, EFO, MIFireE, CFO

While I have not had much input (via Twitter or post comments), I have been working on the Building Factors map to include factors related to the surrounding environment and to revise fire protection systems, construction, fuel, size, and ventilation profile.

Surrounding Environment

Previous versions of the fire behavior indicators (FBI) concept map considered wind effects as a component of air track (which it influences significantly), but did not consider other environmental influences on fire behavior. After considerable thought, I recognized that building factors (and to some extent all of the FBI) can be viewed like Matryoshka Dolls (nested Russian dolls) when used to think about a single compartment, the building, or the building in its surrounding environment.

Environmental factors include exposures (which fire can extend from or to), ambient weather conditions, and terrain. Weather and terrain likely deserve a bit of explanation. While these factors are recognized as major players in wildland fire behavior, their influence is often not as quickly recognized in the built environment. Wind is likely the greatest meteorological concern when dealing with compartment fires. As discussed in prior posts (Wind Driven Fires, NIST Wind Driven Fire Experiments: Establishing a Baseline, Evaluating Firefighting Tactics Under Wind Driven Conditions), wind driven fires present a significant threat to firefighters. However, while buildings are generally designed to minimize the impact of temperature, humidity, and precipitation on their occupants, these factors can influence fire behavior directly or indirectly. For example, combustible exterior surfaces (e.g., wood shingle or shake roofs) present an increased hazard if humidity is low and ambient temperature is high. The influence of terrain may not be quite as obvious. In some cases, terrain may influence wind effects and in others slope may result in differences in elevation on each side of the building. When unrecognized, this has been a factor in a number of firefighter fatalities due to the resulting air track and path of fire spread from lower, to upper floors. For example see NIOSH (1999) Death in the Line of Duty Report F99-21 and Simulation of the Dynamics of the Fire at 3146 Cherry Road NE, Washington D.C. (NIST, 2000).

Fire Protection Systems

Fire suppression systems such as automatic sprinklers can obviously have a direct influence on fire development in a protected compartment. Similarly, fire detection may reduce the time between ignition and intervention by the fire department. However, prior versions of the FBI concept map did not include passive fire protection such as fire rated separations (other than generically as compartmentation).

Construction & Fuel

Prior versions of the FBI map linked Building to Contents and Construction. I have changed this to consider both contents and construction as fuel, while maintaining a link between building factors and construction as there are other facets of construction that can influence fire behavior. However, this area of the map remains a bit tentative (with more work to be done). Other changes to this part of the map include the addition of fire load density (kJ/m2) and increasing clarity of the concepts related to flow rate requirements for fire control.

Size

The concept of size can be a bit confusing as it applies to individual compartments (habitable or void spaces), interconnected compartments, and the entire building. Refinements include the addition of void spaces and normal door position to the concept of compartmentation.

Ventilation Profile

Thermal performance of potential openings has been added to ventilation profile, recognizing that single pane windows perform considerably different than multi-pane, energy efficient windows under fire conditions. In addition, a note was added to clarify that ventilation may be from compartment to compartment or from the building to the external environment.

Figure 1. Building Factors Concept Map v5.2.2.1

You can also download a larger, printer friendly version of the Building Factors Concept Map v5.2.2.1 (including notes made during development). Several colleagues who have had a look at this map observed that it is extremely complicated. While this is true, if you take the time to examine each of the factors and give some thought to the interrelated influences on fire behavior, it becomes a bit clearer. Remember that this is my representation of the concepts, yours will likely be a bit different! As always, feedback is greatly appreciated.

Subsequent posts will examine the rest of the B-SAHF (Building, Smoke, Air Track, Heat, & Flame) organizing scheme for fire behavior indicators.

Ed Hartin, MS, EFO, MIFireE, CFO

References

National Institute for Occupational Safety and Health (NIOSH) (1999) Death in the line of duty report F99-21. Retrieved July 2, 2009 from http://www.cdc.gov/niosh/fire/pdfs/face9921.pdf

National Insitute for Standards and Technology (NIST). Simulation of the Dynamics of the Fire at 3146 Cherry Road NE, Washington D.C. Retrieved July 2, 2009 from http://www.fire.nist.gov/CDPUBS/NISTIR_6510/6510c.pdf

In Reading the Fire: How to Improve Your Skills and Fire Behavior Indicators: Building Factors we started the process of developing a personal fire behavior indicators (FBI) concept map. I am working along with you to expand and refine my FBI Concept Map (Version 5.2.1).

Reading the Fire

I regularly post B-SAHF (Building, Smoke, Air Track, Heat, and Flame) Exercises to provide the opportunity to practice reading the fire. However, photos and video clips can also provide a great opportunity to focus in on a single type of indicator (such as building factors). Dig out the work in progress on your FBI concept map and have a look at the following video clips and focus your attention on building factors.

1. What type of construction was involved? How (or did) this factor influence fire behavior?
2. What other building and occupancy characteristics may have had an impact on fire behavior?
3. Are the factors you identified on your concept map? If not, add them to the map or list them in a staging area until you have determined where they might go on the map.

Los Angeles County Commercial Fire

Vancouver BC Apartment Fire

Los Angeles City Commercial Fire

What additions have you made to your FBI concept map? If you found this useful, poke around on YouTube and continue to apply this method to help you develop and refine the building factors (and other elements) of your map.

Step Back and Look at the Entire Picture

I would not want to waste the opportunity to engage with the rest of the B-SAHF indicators. Download and print three copies of the B-SAHF Worksheet. Consider the information provided in each of the short video clips and complete the worksheet for each. First, describe what you observe in terms of the Building, Smoke, Air Track, Heat, and Flame Indicators and then answer the following five standard questions?

1. What additional information would you like to have? How could you obtain it?
2. What stage(s) of development is the fire likely to be in (incipient, growth, fully developed, or decay)?
3. What burning regime is the fire in (fuel controlled or ventilation controlled)?
4. What conditions would you expect to find inside this building?
5. How would you expect the fire to develop over the next two to three minutes

Next Post

I have spent the last several days attending the Florida State Fire College Live Fire Training Instructor (LFTI) course being delivered at the Oregon Public Safety Academy in Salem, Oregon. My next post will provide an overview and critique of this excellent course.

Ed Hartin, MS, EFO, MIFireE, CFO

Fire Behavior Indicators – A Quick Review

The B-SAHF (Building, Smoke, Air Track, Heat, & Flame) organizing scheme for fire behavior indicators provides a sound method for assessment of current and potential fire behavior in compartment fires. The following provides a quick review of each of these indicator types.

Figure 1. B-SAHF

Building: Many aspects of the building (and its contents) are of interest to firefighters. Building construction influences both fire development and potential for collapse. The occupancy and related contents are likely to have a major impact on fire dynamics as well.

Smoke: What does the smoke look like and where is it coming from? This indicator can be extremely useful in determining the location and extent of the fire. Smoke indicators may be visible on the exterior as well as inside the building. Don’t forget that size-up and dynamic risk assessment must continue after you have made entry!

Air Track: Related to smoke, air track is the movement of both smoke (generally out from the fire area) and air (generally in towards the fire area). Observation of air track starts from the exterior but becomes more critical when making entry. What does the air track look like at the door? Air track continues to be significant when you are working on the interior.

Heat: This includes a number of indirect indicators. Heat cannot be observed directly, but you can feel changes in temperature and may observe the effects of heat on the building and its contents. Remember that you are insulated from the fire environment, pay attention to temperature changes, but recognize the time lag between increased temperature and when you notice the difference. Visual clues such as crazing of glass and visible pyrolysis from fuel that has not yet ignited are also useful heat related indicators.

Flame: While one of the most obvious indicators, flame is listed last to reinforce that the other fire behavior indicators can often tell you more about conditions than being drawn to the flames like a moth. However, that said, location and appearance of visible flames can provide useful information which needs to be integrated with the other fire behavior indicators to get a good picture of conditions.

It is important not to focus in on a single indicator, but to look at all of the indicators together. Some will be more important than others under given circumstances.

Getting Started

Considering the wide range of different building types and occupancies, developing a concept map of the factors and interrelationships that influence fire behavior is no simple task. As you begin this process, keep in mind that it is important to move from general concepts to more specific details. For example, you might select construction type, contents, size, ventilation profile, and fire protection systems as the fundamental factors as illustrated in Figure 2. (However, you also might choose to approach this differently!).

Figure 2. Basic Building Factors

Remember that this is simply a draft (as will each successive version of your map)! Don’t get hung up on getting it “right”. The key is to get started and give some thought to what might be important. After adding some detail, you may come back and reorganize the map, identifying another basic element. For example, early versions of this map listed Fire Suppression Systems (e.g., automatic sprinklers) as one of the core concepts. However, after adding some detail, this concept was broadened to Fire Protection Systems (e.g., automatic sprinklers, fire detection, and other types of inbuilt fire protection).

Developing the Detail

Expanding the map requires identification of additional detail for each of the fundamental concepts. If an idea appears to be obviously related to one of the concepts already on the map, go ahead and add it. If you are unsure of where it might go, but it seems important, list it off to the side in a staging area for possible additions. For example, area and height are important concepts related to size. However, compartmentation may be related to size or it may be a construction factor. If you are unsure of where this should appear on the map, place it in the Staging Area for now.

Figure 3. Expanding the Map

Next Steps

Remember that the process of contracting your own map is likely as important as the (never quite) finished product. The following steps may help you expand and refine the building factors segment of the map:

• Look at each of the subcategories individually and brainstorm additional detail. This works best if you collaborate with others.
• Take your partially completed map and notes and visit several different types of buildings. Visualize how a fire might develop and what building features would influence this process.
• Examine the incident profiled in the Remember the Past segment of this post and give some thought to how building factors may have influenced fire behavior and the outcome of this incident.

In addition, I am still posing questions related to B-SAHF using Twitter. Have a look [http://twitter.com/edhartin] and join in by responding to the questions. While this is not a familiar tool to most firefighters, I think that it has great potential.

Thanks

I would also like to thank Senior Instructor Jason Collits of the New South Wales (Australia) Fire Brigades and Lieutenant Matt Leech of Tualatin Valley Fire and Rescue (also an Instructor Trainer with CFBT-US, LLC) for their collaborative efforts on extending and refining our collective understanding of the B-SAHF indicators. Jason and Matt have been using Bubbl.us to develop and share their respective maps and I will be integrating their work into future posts on Fire Behavior Indicators.

Figure 4 Jason Collits and Matt Leech

Remember the Past

Yesterday was the eighth anniversary of a tragic fire in New York City that claimed the lives of three members of FDNY as a result of a backdraft in the basement of a hardware store.

June 17, 2001
Firefighter First Grade John J. Downing, Ladder 163
Firefighter First Grade Brian D. Fahey, Rescue 4
Firefighter First Grade Harry S. Ford, Rescue 3
Fire Department City of New York

Fire companies were dispatched to a report of a fire in a hardware store. The first- arriving engine company, which had been flagged down by civilians in the area prior to the dispatch, reported a working fire with smoke venting from a second-story window.

A bystander brought the company officer from the first-arriving engine company to the rear of the building where smoke was observed venting from around a steel basement door. The first-arriving command officer was also shown the door and ordered an engine company to stretch a line to the rear of the building. A ladder company was ordered to the rear to assist in opening the door; Firefighter Downing was a member of this company. The first-due rescue company, including Firefighters Fahey and Ford, searched the first floor of the hardware store and assisted with forcible entry on the exterior.

The incident commander directed firefighters at the rear of the building to open the rear door and attack the basement fire. Firefighters on the first floor were directed to keep the interior basement stairwell door closed and prevent the fire from extending. The rear basement door was reinforced, and a hydraulic rescue tool was employed to open it. Once the first door was opened, a steel gate was found inside, further delaying fire attack.

Firefighters Downing and Ford were attempting to open basement windows on the side of the building, and Firefighter Fahey was inside of the structure on the first floor.

An explosion occurred and caused major structural damage to the hardware store. Three fire-fighters were trapped under debris from a wall that collapsed on the side of the hardware store; several firefighters were trapped on the second floor; firefighters who were on the roof prior to the explosion were blown upwards with several firefighters riding debris to the street below; and fire-fighters on the street were knocked over by the force of the explosion.

The explosion trapped and killed Firefighters Downing and Ford under the collapsed wall; their deaths were immediate. Firefighter Fahey was blown into the basement of the structure. He called for help on his radio, but firefighters were unable to reach him in time.

The cause of death for Firefighters Downing and Ford was internal trauma, and the cause of death for Firefighter Fahey was listed as asphyxiation. Firefighter Fahey’s carboxyhemoglobin level was found to be 63%.

In addition to the three fatalities, 99 firefighters were injured at this incident. The fire was caused when children – two boys, ages 13 and 15 – knocked over a gasoline can at the rear of the hard-ware store. The gasoline flowed under the rear doorway and was eventually ignited by the pilot flame on a hot water heater.

For additional information on this incident, see the following:

NIOSH Death in the Line of Duty Report F2001-23,

Simulation of the Dynamics of a Fire in the Basement of a Hardware Store

Incident Photos by Steve Spak

Ed Hartin, MS, EFO, MIFireE, CFO

References

Grimwood, P., Hartin, E., McDonough, J., & Raffel, S. (2005). 3D firefighting: Training, techniques, & tactics. Stillwater, OK: Fire Protection Publications.

Hartin, E. (2007) Fire behavior indicators: Building expertise. Retrieved June 17, 2009 from www.firehouse.com.

Hartin, E. (2007) Reading the fire: Building factors. Retrieved June 17, 2009 from www.firehouse.com.

National Institute for Occupational Safety and Health (NIOSH). (2003) Death in the line of duty report F2001-23. Retrieved June 18, 2009 from http://www.cdc.gov/niosh/fire/pdfs/face200123.pdf

Bryner, N. & Kerber, S (2004) Simulation of the dynamics of a fire in the basement of a hardware store – New York, June 17, 2001 NISTR 7137. Retrieved June 18, 2009 from http://www.fire.nist.gov/bfrlpubs/fire06/PDF/f06006.pdf

United States Fire Administration (USFA) Firefighter fatalities in 2001. Retrieved June 18, 2009 from http://www.usfa.dhs.gov/downloads/pdf/publications/fa-237.pdf

Congratulations!

I would like to offer my congratulations to my two friends and colleagues Inspector John McDonough, ASFM of the New South Wales Fire Brigades and Acting Inspector Shan Raffel, CIFireE, EngTech, ASFM of Queensland Fire Rescue on receiving the Australian Fire Service Medal (AFSM) for distinguished service to their nation’s fire service. This is the second accolade for Shan in the last several months as he was recognized as a Companion of the Institution of Fire Engineers (IFE) for his work as national president and his tireless work for IFE Australia. Outstanding work gentlemen, honors well deserved!

Figure 1 ASFM Recpients Shan Raffel (left) and John McDonough (right)

B-SAHF! Master Your Craft

In Reading the Fire: B-SAHF, I introduced the B-SAHF (Building, Smoke, Air Track, Heat, and Flame) conceptual framework for reading the fire and have subsequently provided a series of video clips and photos to provide an opportunity to exercise your skill in reading the fire. While looking at video, photos (and actual incidents) may help build your knowledge and skill, different types of practice and knowledge building can also further your professional development.

Concept Maps

A concept map is a graphic tool for representing knowledge (Novak & Cañas, 2008). The map illustrates concepts and their relationships to one another (similar to an electrical circuit diagram or road map). Concept maps use a hierarchical form (similar to an organizational chart) with general concepts at the top and details further down. Mind maps are a similar tool often used in brainstorming that use a radial hierarchy with a tree-like hierarchy branching out from the center. I draw on both of these approaches in describing fire behavior indicators. A radial hierarchy is used as the foundation, but other relationships are illustrated and concepts can be interconnected in a variety of different ways.

A key step in improving your ability to read the fire is to think about what you should be looking for. Identifying key indicators and thinking about what they mean can be an important step in developing and improving your knowledge and skill. I find that this is an ongoing process as I continue to add to and refine my fire behavior indicators concept map. This map is not a fireground tool or a checklist of things to look for, but serves as a representation of my understanding and learning. While I am willing to share this map (Ed’s B-SAHF Map v5.2.1), it is more useful for you to build your own, representing your own understanding of these indicators and concepts.

Concept maps can be created using a pencil and paper, Post-It notes and an easel pad or white board, or using a computer with drawing software or a program specifically created for concept mapping. At one point or another, I have used each of these tools and find that they all have advantages and disadvantages. The tools you use are not as important as the mental process of collaborating with others and creating your map.

The Starting Point

Without getting bogged down an a long discussion of the educational and psychological foundations for concept mapping, it is important to understand that development of concept maps supports meaningful rather than rote learning. Rote learning often involves simple memorization. Meaningful learning requires three conditions (Ausubel, 1963).

• Concepts must be clear and presented with common language and examples connected to the learner’s prior knowledge.
• The learner must have relevant prior knowledge. Note that the learner does not require expertise, but needs sufficient knowledge to make sense of the concepts involved.
• Most importantly, the learner must choose to learn in a meaningful way.

Many firefighters struggle with creating mind maps (at first) because much of fire service training focuses on rote learning. However, I find that this challenge can easily be overcome if firefighters recognize the value of exploring the key fire behavior indicators and their relationships to one another.

Developing a concept map starts with a focus question that specifies the problem or issue that the map is intended to help resolve. The fire behavior indicators (FBI) concept map starts with the following focus question:

What building, smoke, air track, heat, and flame indicators
provide clues to current and potential fire behavior?

It is important to remember that a concept map is never finished. After you develop the first draft, it is always necessary to revise the map to increase clarity or add important concepts that you discover as work continues. For example, my FBI Concept Map is on Version 5.2.1, indicating five major revisions and 21 minor revisions or additions over seven years!

Knowledge Soup

The best concept maps are not developed in a vacuum. Collaboration with others can help us identify additional information and provides ideas that we may not have thought of on our own. For example, the current version of my FBI concept map started as my collaboration with Shan Raffel. However, it has evolved to include suggestions from hundreds of CFBT course participants.

Propositions or ideas developed by a group of learners may be thought of as ingredients in a kind of “knowledge soup” (Cañas, Ford, Hayes, Brennan, & Reichherzer, 1995, p. 4). The learners share the ingredients and each cook their own variation on the soup by constructing their own understanding. One way to approach this is to brainstorm key concepts and ideas before beginning the process of organizing the information and drawing the map.

Technology and Information Sharing

We have an advantage today that firefighters in previous generations did not have. Technology provides unparalleled opportunity for collaboration and learning. For example, this blog provides me with an opportunity to communicate and share information with firefighters around the world in a matter of minutes. In addition to my twice weekly blog posts, micro-blogging using the CFBT-US Twitter page provides a simple and easy method to rapidly share information on a daily (and in some cases hourly) basis.

Recently I have been reading a series of blog posts titled 31 Days to Build a Better Blog on Problogger. This stimulated my thinking about different ways to leverage technology to share information within the fire service and more particularly the compartment fire behavior community. Twitter may provide a simple means for collecting the ingredients needed for the knowledge soup necessary to develop and improve our respective fire behavior indicators concept maps.

This process could be started posting a question focused on one element of the FBI Concept map such as: What key building factors that impact on fire behavior can be used as indicators of current and predicted fire behavior? Readers can then respond (Tweet Back) with brief statements (no more than 140 characters) that identify the factors. All readers would then have access to this information when constructing the Building Indicators segment of their FBI Concept Map.

Another challenge is actually drawing the concept map (some of us are more graphically inclined or skilled than others). Bubble.us is a simple and easy to learn tool that provides a way to organize information as a concept map and share the work with others by e-mail, on the web, or embedded in a web page.

Figure 2. Bubbl.us Concept Map

Use of this software is free (you simply visit the bubbl.us web page, sign up and start creating your map. You can share your map with others to read or you can give them permission to edit the map. While I have not used this software extensively, it appears to be extremely easy to use and an excellent tool to simplify the process of drawing concept maps.

Where to from Here?

All very interesting, but how does this help us improve our ability to read the fire? Originally I had thought about using the “31 Days” concept to reading the fire. However, it will likely take a bit longer than that.

My next post will propose that we begin with an examination of building factors that influence fire behavior and which may serve as useful indicators in situational assessment. In the mean time, visit the CFBT-US Twitter page and respond to the question about building factors! Follow me for regular updates (you can also subscribe to an RSS Feed to receive information in a feed reader or via e-mail).

Each month I will move to the next element in the B-SAHF organizing scheme for fire behavior indicators until we have completed the entire FBI concept map. However, feel free to work ahead!

Ed Hartin, MS, EFO, MIFireE, CFO

References

Ausubel, D. (1963). The psychology of meaningful verbal learning. New York: Grune and Stratton.

Cañas,A., Ford, K., Hayes, P., Brennan, J., & Reichherzer,T. (1995) Knowledge construction and sharing in Quorum. Retrieved June 7, 2009 from http://www.ihmc.us/users/acanas/Publications/AIinEd/AIinEd.pdf

Novak. J. & Cañas, A. (2008). The theory underlying concept maps and how to construct and use them. Retrieved June 7, 2009 from http://cmap.ihmc.us/Publications/ResearchPapers/TheoryUnderlyingConceptMaps.pdf

Application of the B-SAHF (Building, Smoke, Air Track, Heat, & Flame) organizing scheme for critical fire behavior indicators to photographs or video of structure fires provides an excellent opportunity to develop your knowledge of fire behavior and skill in reading the fire.

This post uses a short video clip from Providence, RI to provide an opportunity to practice reading the fire.

Taxpayer Fire

Download and print the B-SAHF Worksheet. Consider the information provided in the short video clip. First, describe what you observe in terms of the Building, Smoke, Air Track, Heat, and Flame Indicators. Second, answer the following five standard questions:

1. What additional information would you like to have? How could you obtain it?
2. What stage(s) of development is the fire likely to be in (incipient, growth, fully developed, or decay)?
3. What burning regime is the fire in (fuel controlled or ventilation controlled)?
4. What conditions would you expect to find inside this building?
5. How would you expect the fire to develop over the next two to three minutes

In addition give some thought to the following four questions focused specifically on this incident:

1. Where do you think the fire is located? Why?
2. Do you observe any changes in conditions? What might these changes indicate?
3. What avenues of fire spread would be of concern? How does this relate to building factors?
4. It appears that horizontal ventilation is being conducted by interior crews on Floor 2, Side A. How is this likely to influence interior conditions and fire behavior?

Ed Hartin, MS, EFO, MIFireE, CFO