My last post asked a number of questions focused on results of baseline compartment fire tests conducted by the National Institute for Standards and Technology (NIST) as part of a research project on  Firefighting Tactics Under Wind Driven Conditions.  This post looks at the answers to these questions and continues with an examination of NIST’s experiments in the application of wind control devices for anti-ventilation.

Questions

Generally being practically focused people, firefighters do not generally dig into research reports. However, the information on the baseline test conducted by NIST raised several interesting questions that have direct impact on safe and effective firefighting operations. First consider possible answers to the questions and then why this information is so important (the “So what?”!).

Figure 1. Heat Release Rate Comparison

Note: Adapted from Firefighting Tactics Under Wind Driven Conditions.

Heat Release Rate (HRR) Questions: Examine the heat release rate curves in Figure 1 and answer the following questions:

• Why are these two HRR curves different shapes?
• In each of these two cases, what might have influenced the rate of change (increase or decrease in HRR) and peak HRR?
• What observations can you make about conditions inside the test structure and heat release rate (in particular, compare the HRR and conditions at approximately 250 and 350 seconds)?

Answers: The HRR test for the bed and waste container was conducted under fuel controlled conditions (oxygen supply was not restricted). The higher HRR in the compartment fire experiment results from increased fuel load (e.g., additional furniture, carpet). After reaching its peak, HRR in the compartment fire drops off slowly as the fire becomes ventilation controlled and the fire continues in a relatively steady state of combustion (limited by the air supplied through the lower portion of the bedroom window)

The rate of change in heat release rate under fuel controlled conditions is dependent on the characteristics and configuration of the fuel.  However, in the case of the compartment fire test, the rate of change is also impacted by limited ventilation. As illustrated in the compartment fire curve, the fire quickly became ventilation controlled and HRR rose slowly until the window failed and was fully cleared by researchers.

At 250 seconds (when the window was vented) HRR rose extremely rapidly as the fire in the bedroom rapidly transitioned from the growth through flashover to fully developed stage. At 350 seconds the fire had again become ventilation controlled and was burning in a relatively steady state limited by the available oxygen.

The fully developed fire in the bedroom also became ventilation controlled due to limited ventilation openings, resulting in HRR leveling off with relatively steady state combustion based on the available oxygen.

Figure 2. Bedroom Temperature

Note: Adapted from Firefighting Tactics Under Wind Driven Conditions.

Temperature Questions: Examine the temperature curves in Figure 2 and answer the following questions:

• What can you determine from the temperature curves from ignition until approximately 250 seconds?
• How does temperature change at approximately 250 seconds? Why did this change occur and how does this relate to the data presented in the HRR curve for Experiment 1 (Figure 1)?
• What happens to the temperature at the upper, mid, and lower levels after around 275 seconds? Why does this happen?

Answers: Temperature at the upper levels of the compartment increased much more quickly than at the lower level and conditions in the compartment remained thermally stratified until the ceiling temperature exceeded 600^o C. At approximately 250 seconds, the compartment flashed over resulting in a rapid increase in temperature at mid and lower levels. This change correlates with the rapid increase in HRR occurring at approximately 250 seconds in Figure 1. Turbulent, ventilation controlled combustion resulted in a loss of thermal layering with temperatures in excess of 600^o C from ceiling to floor. At around 275 seconds.

Figure 3. Total Hydrocarbons at the Upper Level

Note: Adapted from Firefighting Tactics Under Wind Driven Conditions.

Total Hydrocarbons (THC) Questions: Examine the THC curves in Figure 3 and answer the following questions:

• Why did the THC concentration in the living room rise to a higher level than in the bedroom?
• Why didn’t the gas phase fuel in the living room burn?
• How did the concentration of THC in the bedroom reach approximately 4%? Why wasn’t this gas phase fuel consumed by the fire?

Answers: Oxygen entering the compartments through the window was being used by combustion occurring in the bedroom. Low oxygen concentration limited combustion in the living room and allowed accumulation of a higher concentration of unburned fuel. While the oxygen concentration in the bedroom was higher, the fire was still ventilation controlled and not all of the gas phase fuel was able to burn inside this compartment.

So What?

What do the answers to the preceding questions mean to a company crawling down a dark, smoky hallway with a hoseline or making a ventilation opening at a window or on the roof?

Emergency incidents do not generally occur in buildings equipped with thermocouples, heat flux gages, gas monitoring equipment, and pre-placed video and thermal imaging cameras. Understanding the likely sequence of fire development and influencing factors is critical to not being surprised by fire behavior phenomena. These tests clearly illustrated how burning regime (fuel or ventilation controlled) impacts fire development and how changes in ventilation can influence fire behavior. The total hydrocarbon concentration and ventilation controlled combustion in the living room would present a significant threat in an emergency incident. How might conditions change if the fire in the bedroom was controlled and oxygen concentration began to increase? Ignition of the gas phase fuel in this compartment could present a significant threat (see Fire Gas Ignitions) or even prove deadly (future posts will examine the deaths of a captain and engineer in a fire gas ignition in California).

Anti-Ventilation

For years firefighters throughout the United States have been taught that ventilation is “the planned and systematic removal of heat, smoke, and fire gases, and their replacement with fresh air”. This is not entirely true! Ventilation is simply the exchange of the atmosphere inside a compartment or building with that which is outside. This process goes on all the time. What we have thought of as ventilation, is actually tactical ventilation. This term was coined a number of years ago by my friend and colleague Paul Grimwood (London Fire Brigade, retired). It is essential to recognize that there are two sides to the ventilation equation, one is removal of the hot smoke and fire gases and the other is introduction of air. Increased ventilation can improve tenability of the interior environment, but under ventilation controlled conditions will result in increased heat release rate.

Another tactic change the ventilation profile and influence fire behavior and conditions inside the building is to confine the smoke and fire gases and limit introduction of air (oxygen) to the fire. Firefighters in the United States often think of this as confinement, but I prefer the English translation of the Swedish tactic, anti-ventilation. This is the planned and systematic confinement of heat, smoke, and fire gases and exclusion of fresh air. The concept of anti-ventilation is easily demonstrated by limiting the air inlet during a doll’s house demonstration (see Figure 4). Closing the inlet dramatically reduces heat release rate and if sustained, can result in extinguishment.

Figure 4. Anti-Ventilation in a Doll’s House Demonstration

For a more detailed discussion of the relationship between ventilation and heat release rate see my earlier post on Fuel and Ventilation.

Air Track and Influence of Wind

Air track (movement of smoke and air under fire conditions) is influenced by differences in density between hot smoke and cooler air and the location of ventilation openings. However, wind is an often unrecognized influence on compartment fire behavior. Wind direction and speed can influence movement of smoke, but more importantly it can have a dramatic influence on introduction of air to the fire.

While the comparison is not perfect, the effects of wind on a compartment fire can be similar to placing a supercharger on an internal combustion engine (see Figure 5). Both dramatically increase power (energy released per unit of time).

Figure 5. Influence of Wind

NIST Wind Control Device Tests

As discussed in Wind Driven Fires, the effects of wind on compartment fire behavior can present a significant threat to firefighters and has resulted in a substantive number of line-of-duty deaths. In their investigation of potential tactical options for dealing with wind driven fires, NIST researchers examined the use of wind control devices (WCD) to limit introduction of air through building openings (specifically windows in the fire compartment in a high-rise building) as illustrated in Figure 6.

Figure 6. Small Wind Control Device

Note: Photo from Firefighting Tactics Under Wind Driven Conditions.

Questions

Give some thought to how wind can influence compartment fire behavior and how a wind control device might mitigate that influence.

• How would a strong wind applied to an opening (such as the bedroom window in the NIST tests) influence fire behavior in the compartment of origin and other compartments in the structure?
• How would a wind control device deployed as illustrated in Figure 5 influence fire behavior?
• While the wind control device illustrated in Figure 5 was developed for use in high-rise buildings, what applications can you envision in a low-rise structure?
• What other anti-ventilation tactics could be used to deal with wind driven fires in the low-rise environment?

The Story Continues…

My next post will address the answers to these questions (please feel free to post your thoughts) and examine the results of NIST’s tests on the use of wind control devices for anti-ventilation.

References

Madrzykowski, D. & Kerber, S. (2009). Fire Fighting Tactics Under Wind Driven Conditions. Retrieved (in four parts) February 28, 2009 from http://www.nfpa.org/assets/files//PDF/Research/Wind_Driven_Report_Part1.pdf; http://www.nfpa.org/assets/files//PDF/Research/Wind_Driven_Report_Part2.pdf;http://www.nfpa.org/assets/files//PDF/Research/Wind_Driven_Report_Part3.pdf;http://www.nfpa.org/assets/files//PDF/Research/Wind_Driven_Report_Part4.pdf.

Ed Hartin, MS, EFO, MIFireE, CFO

My last post introduced a National Institute for Standards and Technology research project examining firefighting tactics for wind driven structure fires (particularly those occurring in high-rise buildings). The report on this research Firefighting Tactics Under Wind Driven Conditions contains a tremendous amount of information on this series of experiments including heat release rate, heat flux, pressure, velocity, and gas concentrations during each of the tests along with time sequenced still images (video and infrared video capture).

This post will examine the initial test used to establish baseline conditions for evaluation of wind driven fire conditions and tactics. Readers are encouraged to download a copy of the report and dig a bit deeper!

Test Conditions

In Wind Driven Fires, I provided an overview of the multi-compartment test structure and fuel load used for this series of experiments. To quickly review, the test structure was comprised of three compartments; Bedroom, Target Room (used to assess tenability in a compartment adjacent to the ventilation flow), and Living Room, along with an interconnecting hallway (between the Bedroom and Living Room) and exterior corridor. Fuel load consisted of typical residential furnishings in the bedroom and living room along with carpet and carpet pad throughout the structure. The target room (used to assess tenability in a potential place of refuge for occupants or firefighters) did not contain any furnishings. Different types of doors (metal, hollow core wood, etc.) were used in the tests to evaluate performance under realistic fire conditions.

Two ventilation openings were provided, a ceiling vent in the Northwest Corridor (providing a flow path from the involved compartment(s) into the corridor) and a window (fitted with glass) in the compartment of origin. During the fire tests, the window failed due to differential heating (of the inner and outer surface of the glass) and was subsequently removed by researchers to provide the full window opening for ventilation.

Figure 1. Isometric Illustration of the Test Structure

Note: The location of fuel packages in the bedroom and living room is shown on the Floor Plan provided in Wind Driven Fires post.

The structure was constructed under a large oxygen consumption calorimetry hood which allowed measurement of heat release rate (once products of combustion began to exit the ceiling vent). In addition, thermocouples, heat flux gages, pressure transducers, and bidirectional probes were used to measure temperature, heat flux, pressure, and gas flow within and out of the structure. Gas sampling probes were located at upper and lower levels, (0.61 m (2′) and 1.83 m (6′) below the ceiling respectively) in the bedroom and living room. Researchers measured oxygen, carbon dioxide, carbon monoxide, and total hydrocarbon concentration during each test.

Experiment 1 Baseline Test

This experiment was different than the others in the series as no external wind was applied to the structure. The fire was ignited in the bedroom and allowed to develop from incipient to fully developed stage in the bedroom.

After 60 seconds the fire had extended from the trash can (first fuel package ignited) to the bed and chair. At this point a visible smoke layer had developed in the bedroom.

120 seconds after ignition, the smoke layer had reached a thickness of 1.2 m (4′) in the bedroom, hallway, and living room. At this point, smoke had just started to enter the corridor. Conditions in the target room were tenable with little smoke infiltration.

At 180 seconds after ignition, the smoke layer was 1.5 m (5′) deep and had extended from the living room into the corridor. Flames from the bed and chair had reached the ceiling. Hot smoke and clear air was well stratified with a distinct boundary between upper and lower layers. Smoke had begun to infiltrate at the top of the door to the target room.

240 seconds after ignition the window started to fail due to flame impingement and the smoke layer extended from ceiling to floor in the bedroom. The smoke layer in the living room had reached a depth of 2.1 m (7′) from the ceiling. Temperature in the corridor remained well stratified.

248 seconds after ignition the researchers cleared the remaining glass from the window to provide a full opening for ventilation. As the glass was removed, the size of the fire in the bedroom and flames exiting the window increased. A thin smoke layer had developed at ceiling level in the target room.

At 300 seconds, flames had begun to burn through the wood, hollow core door to the target room and flaming combustion is also visible in the hallway at the bottom of this door. Flames continued to exit the top 2/3 of the window.

360 seconds into the test, the fire in the bedroom reached steady state (post-flashover), ventilation controlled combustion. The door to the target room has burned through with a dramatic increase in temperature as the room fills with smoke.

Suppression using fixed sprinklers and a hoseline began at 525 seconds.

Fire development during this experiment was not particularly remarkable with conditions that could typically be expected in a residential occupancy. So, what can we learn from this test?

Heat Release Rate

NIST researchers examined the heat release rate of individual fuel packages and combinations of fuel packages prior to the compartment fire tests. These tests conducted in an oxygen consumption calorimeter were performed with the fire in a fuel controlled burning regime. Figure 2 illustrates the heat release rate from the combination of waste container and bed fuel packages and the heat release rate generated during Experiment 1 (in which the initial fuel packages ignited were the waste container and bed located inside the bedroom.

Figure 2. Heat Release Rate Comparison

Note: Adapted from Firefighting Tactics Under Wind Driven Conditions.

Questions: Examine the heat release rate curves in Figure 2 and answer the following questions:

• Why are these two HRR curves different shapes?
• In each of these two cases, what might have influenced the rate of change (increase or decrease in HRR) and peak HRR?
• What observations can you make about conditions inside the test structure and heat release rate (in particular, compare the HRR and conditions at approximately 250 and 350 seconds)?

Temperature

During the experiments temperature was measured in each of the compartments at multiple levels. Figure 3 illustrates temperature conditions in the bedroom at 0.03 m (1″), 1.22 m (4′) and 2.13 m (7′) down from the ceiling during Experiment 1.

Figure 3. Bedroom Temperature

Note: Adapted from Firefighting Tactics Under Wind Driven Conditions. Position.

Questions: Examine the temperature curves in Figure 3 and answer the following questions:

• What can you determine from the temperature curves from ignition until approximately 250 seconds?
• How does temperature change at approximately 250 seconds? Why did this change occur and how does this relate to the data presented in the HRR curve for Experiment 1 (Figure 2)?
• What happens to the temperature at the upper, mid, and lower levels after around 275 seconds? Why does this happen?

Total Hydrocarbons

In addition to HRR and temperature, researchers measured gas concentrations inside the compartments at the upper and lower levels. Figure 4 shows the concentration (in % volume) of total hydrocarbons in the bedroom and living room. Concentration of total hydrocarbons is a measure of gas phase fuel (pyrolysis products) in the upper layer.

Figure 4. Total Hydrocarbons at the Upper Level

Note: Adapted from Firefighting Tactics Under Wind Driven Conditions. Position.

Questions: Examine the THC curves in Figure 4 and answer the following questions:

• Why did the THC concentration in the living room rise to a higher level than in the bedroom?
• Why didn’t the gas phase fuel in the living room burn?
• How did the concentration of THC in the bedroom reach approximately 4%? Why wasn’t this gas phase fuel consumed by the fire?

The Story Continues…

My next post will address the answers to these questions (please feel free to post your thoughts) and provide an overview of NIST’s initial tests on the use of wind control devices for anti-ventilation.

Ed Hartin, MS, EFO, MIFireE, CFO

Weather, Topography, and Fuel

In S-190 Introduction to Wildland Fire Behavior, firefighters learn that weather, topography, and fuel and the principal factors influencing fire behavior in the wildland environment. How might this important concept apply when dealing with fires in the built environment? Factors influencing compartment fire behavior have a strong parallel to those in the wildland environment. Principal influences on compartment fire behavior include fuel, configuration (of the compartment and building), and ventilation.

Wind Driven Compartment Fires

As buildings are designed to minimize the influence of weather on their contents and occupants, weather is not generally considered a major factor in compartment fires. However, this is not always the case. As wildland firefighters recognize, wind can be a major influence on fire behavior and strong winds present a significant threat of extreme fire behavior.

Under fire conditions, unplanned ventilation involves all changes influencing exhaust of smoke, air intake, and movement of smoke within the building that are not part of the incident action plan. These changes may result from the actions of exiting building occupants, fire effects on the building (e.g., failure of window glass), or a wide range of other factors.

Changes in ventilation can increase fire growth and hot smoke throughout the building. Failure of a window in the fire compartment in the presence of wind conditions can result in a significant and rapid increase in heat release. If this is combined with open doors to corridors, unprotected stairwells, and other compartments, wind driven fire conditions have frequently resulted in firefighter injuries and fatalities (see Additional Reading).

NIST Research on Wind Driven Fires

From November 2007 to January 2008, the National Institute of Standards and Technology conducted a series of experiments examining firefighting tactics dealing with wind driven compartment fires. The primary focus of this research was on the dynamics of fire growth and intensity and the influence of ventilation and fire control strategies under wind driven fire conditions. The results of these experiments are presented in Fire Fighting Tactics Under Wind Driven Conditions, published by The Fire Protection Research Foundation.

Tests conducted at NIST’s Large Fire Test Facility (see Figure 1) included establishment of baseline heat release data for the fuels (bed, chairs, sofa, etc), full scale fire tests under varied conditions (e.g., no wind, wind), and experiments involving control of the inlet opening and varied methods of external water application.

Figure 1. NIST Large Fire Test Facility

Note: Photo adapted from Firefighting Tactics Under Wind Driven Conditions.

The objectives of this study were:

• To understand the impact of wind on a structure fire fueled with residential furnishings in terms of temperature, heat flux, heat release rate, and gas concentrations
• To quantify the impact of several novel firefighting tactics on a wind driven structure fire
• Improve firefighter safety

After conducting a series of tests to determine the heat release rate characteristics of the fuels to be used for the full scale tests, NIST conducted eight full scale experiments to examine the impact of wind on fire spread through the multi-room test structure (see Figure 2) and examine the influence of anti-ventilation using wind control devices and the impact of external water application.

Multi-Room Test Structure

All tests were conducted under the 9 m (30′) x 12 m (40′) oxygen consumption calorimetry hood at the NIST Large Fire Test Facility. The test structure was comprised of three compartments; Bedroom, Target Room (used to assess tenability in a compartment adjacent to the ventilation flow), and Living Room, along with an interconnecting hallway and exterior hallways. A large mechanical fan was positioned 7.9 m (26′) away from the window in the bedroom of the test structure (see Figure 2) to provide consistent wind conditions for the experiments.

Figure 2. Configuration of the Multi-Room Test Structure

Note: Adapted from Firefighting Tactics Under Wind Driven Conditions.

The structure was framed with steel studs and wood truss joist I-beams (TJIs) used to support the ceiling. The interior of the compartments were lined with three layers of 13 mm (1/2″) gypsum board. Multiple layers of gypsum board were used to provide the durability required for repetitive experiments (the inner layer was replaced and repairs made to other layers as needed between experiments).

Used furnishings were purchased from a hotel liquidator to obtain 10 sets of similar furniture to use in the heat release rate and full-scale, multi-compartment experiments. Fuel used in the tests included furniture, nylon carpet, and polyurethane carpet padding (the position major furniture items are illustrated in Figures 2 and 3).  Fuel load was 348.69 kg (768.73 lbs) in the bedroom, 21.5 kg (47.40 lbs) in the hallway, and 217.6 kg (479.73 lbs) in the living room (no contents were placed in the target room).

Figure 3. Bedroom and Living Room Fuel Load

Note: Photos adapted from Firefighting Tactics Under Wind Driven Conditions.

NIST researchers conducted a series of eight full-scale, multi-compartment fire tests. In each case, a fire was started in the Bedroom using a plastic trash container placed next to the bed (see Figure 3).

Figure 3. Placement of the Trash Container

Note: Photos adapted from Firefighting Tactics Under Wind Driven Conditions.

Experiments

The eight tests provided the opportunity to study the dynamics of wind driven compartment fires and several different approaches to limiting the influence of air intake and controlling the fire.

Experiment 1: This test was performed to establish baseline conditions with no wind

Experiment 2: Evaluation of anti-ventilation using a large wind control device placed over the window

Experiment 3: Evaluation of anti-ventilation using a large wind control device placed over the window (second test with a longer pre-burn before deployment of the wind control device).

Experiment 4: Evaluation of anti-ventilation and water application using a small wind control device and 30 gpm (113.6 lpm) spray nozzle from under the wind control device.

Experiment 5: Evaluation of anti-ventilation and water application using a small wind control device and 30 gpm (113.6 lpm) spray nozzle from under the wind control device (second test with a lower wind speed)

Experiment 6: No wind control device, application of water using a hoseline equipped with a combination nozzle at 90 psi (621 kPa) nozzle pressure, providing a flow rate of 80 gpm (303 lpm).

Experiment 7: No wind control device, application of water using a hoseline equipped with a 15/16″ smooth bore nozzle at 50 psi (345 kPa) nozzle pressure, providing a flow rate of 160 gpm (606 lpm) (test was conducted with the living room corridor door closed).

Experiment 8: No wind control device, application of water using a hoseline equipped with a 15/16″ smooth bore nozzle at 50 psi (345 kPa) nozzle pressure, providing a flow rate of 160 gpm (606 lpm) (second test with the living room corridor door open).

Note: The nozzles for these tests (100 gpm at 100 psi combination nozzle and 15/16″ solid stream nozzle were selected as to be representative of those used by the fire service in the United States (personal correspondence, S. Kerber, February 28, 2009). However, it is important to note that in comparing the results, that the combination nozzle was under pressurized (80 psi, rather than 100 psi) resulting in large droplet size. In addition, the 100 gpm flow rate was 50% of that applied through the solid stream nozzle and is likely considerably lower than the flow capability of combination nozzles typically used with 1-3/4″ (45 mm) hose.

Important Findings

The first experiment was conducted without any external wind or tactical intervention. The baseline data generated during this test was critical to evaluating the outcome of subsequent experiments and demonstrated a number of concepts that are critical to firefighter safety:

Smoke is fuel. A ventilation limited (fuel rich) condition had developed prior to the failure of the window. Oxygen depleted combustion products containing carbon dioxide, carbon monoxide and unburned hydrocarbons, filled the rooms of the structure. Once the window failed, the fresh air provided the oxygen needed to sustain the transition through flashover, which caused a significant increase in heat release rate.

Venting does not always equal cooling. In this experiment, post ventilation temperatures and heat fluxes all increased, due to the ventilation induced flashover.

As discussed in early posts, Fuel & Ventilation and Myth of the Self Vented Fire understanding the relationship between oxygen and heat release rate, the hazards presented by ventilation controlled fires, and the influence of ventilation on fire development is critical to safe and effective fireground operations.

Fire induced flows. Velocities within the structure exceeded 5 m/s (11 mph), just due to the fire growth and the flow path that was set-up between the window opening and the corridor vent.

Avoid the flow path. The directional nature of the fire gas flow was demonstrated with thermal conditions, both temperature and heat flux, which were twice as high in the “flow” portion of the corridor as opposed to the “static” portion of the corridor in Experiment 1 [not wind driven]. Thermal conditions in the flow path were not consistent with firefighter survival.

Previous posts have presented case studies based on incidents in Loudoun County Virginia and Grove City, Pennsylvania in which convective flow was a significant factor rapid fire progress that entrapped and injured firefighters, in one case fatally. Previous NIST research investigating a multiple line-of-duty death that occurred in a townhouse fire at 3146 Cherry Road in Washington, DC in 1999 also emphasized the influence of flow path on fire conditions and tenability.

More to Follow

Subsequent posts will examine the NIST wind driven fire tests in greater detail.

Ed Hartin, MS, EFO, MIFireE, CFO

References

Madrzykowski, D. & Kerber, S. (2009). Fire Fighting Tactics Under Wind Driven Conditions. Retrieved (in four parts) February 28, 2009 from http://www.nfpa.org/assets/files//PDF/Research/Wind_Driven_Report_Part1.pdf; http://www.nfpa.org/assets/files//PDF/Research/Wind_Driven_Report_Part2.pdf;http://www.nfpa.org/assets/files//PDF/Research/Wind_Driven_Report_Part3.pdf;http://www.nfpa.org/assets/files//PDF/Research/Wind_Driven_Report_Part4.pdf.

Madrzykowski, D. & Vettori, R. (2000). Simulation of the Dynamics of the Fire at 3146 Cherry Road NE, Washington D.C., May 30, 1999. Retrieved March 1, 2009 from http://fire.nist.gov/CDPUBS/NISTIR_6510/6510c.pdf

Additional Reading

The following investigative reports deal with firefighter line of duty deaths involving wind driven fire events during structural firefighting.

National Institute for Occupational Safety and Health (NIOSH). (1999). Death in the line of duty, Report F99-01. Retrieved February 28, 2009 from http://www.cdc.gov/niosh/fire/pdfs/face9901.pdf

National Institute for Occupational Safety and Health (NIOSH). (1999). Death in the line of duty, Report F98-26. Retrieved February 28, 2009 from http://www.cdc.gov/niosh/fire/pdfs/face9826.pdf

National Institute for Occupational Safety and Health (NIOSH). (2002). Death in the line of duty, Report F2001-33. Retrieved February 28, 2009 from http://www.cdc.gov/niosh/fire/pdfs/face200133.pdf

National Institute for Occupational Safety and Health (NIOSH). (2007). Death in the line of duty, Report F2005-03. Retrieved February 28, 2009 from http://www.cdc.gov/niosh/fire/pdfs/face200503.pdf

National Institute for Occupational Safety and Health (NIOSH). (2008). Death in the line of duty, Report F2007-12. Retrieved February 28, 2009 from http://www.cdc.gov/niosh/fire/pdfs/face200712.pdf

Prince William County Department of Fire and Rescue (2007). Line of duty investigative report: Technician I Kyle Wilson. Retrieved February 28, 2009 from http://www.pwcgov.org/default.aspx?topic=040061002930004566

Texas State Fire Marshal’s Office. (2001). Firefighter Fatality Investigation, Investigation Number 02-50-10. Retrieved February 28, 2009 from http://www.tdi.state.tx.us/reports/fire/documents/fmloddjahnke.pdf

What is Extreme?

There is some debate about the use of the term extreme fire behavior (some of my colleagues indicate that processes such as flashover is not “extreme” but simply “normal” fire behavior). I contend that flashover would potentially be a normal part of fire development, but is also extreme, at least in the context that we are using the word. As defined in the wildland firefighting community:

“Extreme” implies a level of fire behavior characteristics that ordinarily precludes methods of direct control action. One or more of the following is usually involved: high rate of spread, prolific crowning and/or spotting, presence of fire whirls, strong convection column. Predictability is difficult because such fires often exercise some degree of influence on their environment and behave erratically, sometimes dangerously (National Wildfire Coordinating Group Glossary)

In the structural firefighting environment, occurrence of flashover (particularly while firefighters are operating inside the compartment) fits substantially with the description of extreme used by wildland firefighters.

Classification and Understanding

Ontology may be described as definition of a formal representation of concepts and the relationships between those concepts. An ontology provides a shared vocabulary. Unfortunately we do not have a well developed ontology of fire behavior phenomenon and many types of phenomena have more than one definition. As with the use of the word extreme, there is some debate about the need to classify phenomena as being this or that (e.g., flashover or backdraft). I take the position that it is useful (but difficult as we do not have a common classification scheme or ontology). But, I think that it is still worth the effort.

This is a substantive topic for a later post. This post will examine a type of fire gas ignition phenomena that has been involved in a number of incidents in recent years resulting in near misses, injuries, and fatalities.

Fire Gas Ignitions

In a previous post, I posed the question: Backdraft or Smoke Explosion?. This post used a video clip to open a discussion of the difference between these two phenomena. A smoke (or fire gas) explosion is a type of fire gas ignition, but there are a number of other types of fire gas ignition that present a hazard during firefighting operations.

All fire gas ignitions (FGI) involve combustion of accumulated unburned pyrolysis products and flammable products of incomplete combustion existing in or transported into a flammable state (Grimwood, Hartin, McDonough, & Raffel, 2005). In a smoke explosion, ignition of a confined mass of smoke gases and air that fall within the flammable range results in extremely rapid combustion (deflagration), producing an significant overpressure which can result in structural damage. However, what happens if the mass of gas phase fuel is not pre-mixed within its flammable range and does not burn explosively?

The general term Fire Gas Ignition, encompasses a number of phenomena that are related by the common characteristic that they involve rapid combustion of gas phase fuel consisting of pyrolizate and unburned products of incomplete combustion that are in or are transported into a flammable state. For now, let’s differentiate these phenomena from backdraft on the basis of the concentration of gas phase fuel (backdraft involving a higher concentration than fire gas ignition).

Fire gas ignition can involve explosive combustion (as in a smoke explosion) or rapid combustion that does not produce the same type of overpressure as an explosion. One such phenomenon is a flash fire. In this case, gas phase fuel ignites and burns for short duration, but does not release sufficient energy for the fire to transition to a fully developed stage (as occurs in flashover). While a flash fire may not result in flashover, the energy release is still significant and heat flux (energy transferred) can be sufficient result in damage to personal protective equipment, injury and death. This post uses a case study to examine the flash fire phenomenon.

Residential Fire

This case study is based on a near-miss incident involving extreme fire behavior during a residential fire that occurred on October 9, 2007 at 1119 William Street in Omaha, Nebraska. Special thanks to Captain Shane Hunter (Omaha Fire Department Training Officer) for sharing this post incident analysis and lessons learned.

Unlike many of the incidents used as case studies, no one died or was injured during incident operations. In this near miss incident, the firefighters and officers involved escaped without injury, but the outcome could easily have been quite different.

Weather Conditions

Weather was typical for early fall with a light breeze from the south (blowing towards Side C of the fire building).

Building Information

The fire building was a one and a half story, wood frame dwelling with a basement (see Figure 1). The attic space had been renovated into three separate compartments to provide additional living space.

Figure 1. Exterior View Side A

Figure 2. Floor 2 Layout

Conditions on Arrival

When the first company arrived they observed fire and smoke from the second floor window (see Figure 1) and reported a working fire. The doors and windows on the first floor were closed.

Firefighting Operations

What initial actions were taken? A 200′ hoseline was extended through the door located on Side A and through the living room and kitchen to the stairway to the second floor, which was located at the C/D corner of the structure (Figures 2 and 3).

Figure 5 & 6. Kitchen (view from Floor 1) and Stairwell (view from Floor 2)

What did the fire attack crew observe? The living room and kitchen were clear of smoke and the door to the second floor stairway was closed. When this door was opened and the line was advanced up the stairway to the second floor, the company assigned to fire attack encountered smoke down to floor level on the second floor. Making a left turn at the top of the stairs (see Figure 4) the Captain noted high temperature at the floor level and observed rollover at the ceiling level.

• How did the ventilation profile change when the door to second floor stairway was opened? How might this have changed fire behavior?
• What did the depth of the hot gas layer (from ceiling to floor) indicate about the ventilation profile?
• What did rollover in the center compartment indicate?

The Captain instructed the nozzle operator to apply water to the ceiling. The firefighter on the nozzle applied water in a 30^o fog pattern (continuous application). Simultaneously, a crew working on the exterior vented the second floor window on Side C (see Figures 4 and 6).

How did conditions change? The engine company working on floor 2 heard an audible, whoosh as the hot gas layer ignited producing flames down to floor level. Operation of the hoseline (30^o fog pattern) had no immediate effect. The Captain ordered the crew to retreat into the stairwell and continue water application.

• What extreme fire behavior phenomena occurred?
• What were the initiating events that caused this rapid fire progression?

Figure 4. Floor 2 Side A (Looking Towards Side A)

Figure 5. Floor 2 Side C (Looking Towards Side C)

What action was taken? While the engine company operated from the stairwell, vertical ventilation was completed over the center compartment (see Figures 4 and 5). After the creation of an exhaust opening in the roof, conditions on floor 2 became tenable and the engine crew was able to knock the fire down within several minutes.

• Why did conditions improve quickly after the creation of a vertical exhaust opening?
• What tactical options might have prevented this near miss?

Observations and Analysis

Captain Shane Hunter observed that the initial fire attack crew viewed this incident as an easy job. They thought that an attack from the unburned side would simply push the fire out the window where fire was initially showing on Side A. Why did things turn out so differently than anticipated?

In his analysis of this incident, Captain Hunter points out that there is a considerable difference between a “self-vented” fire and an adequately ventilated fire. As discussed in the April 2008 Officer’s Corner (GFES), horizontally ventilated fires are likely to remain ventilation-controlled. It is important to read the Building, Smoke, Air Track, Heat, and Flame (B-SAHF) indicators to determine the current burning regime (fuel or ventilation-controlled) and anticipate the effect of changes to the ventilation profile.

The fire in the compartment of origin reached flashover resulting in the extension of flames into the center compartment as evidenced by the observation of rollover by the Captain of the engine company performing fire attack. However, the center compartment and the compartment on Side C did not experience flashover (note the condition of contents in the center compartment in Figure 6.). If flashover did not occur in these two compartments, what happened?

In this incident, the fire gases ignited in a flash fire, but combustion did not rapidly transition to a fully developed state in the two compartments adjacent to the compartment of origin.

A flash fire rapidly increases heat release rate, temperature within the compartment and heat flux (as experienced by the fire attack crew in this incident). Like rollover, this phenomenon should not be confused with flashover as fuel in the lower region of the compartment may or may not ignite and sustain combustion. However, fire gas ignition can precede and precipitate flashover (should the fire quickly transition to the fully developed stage).

The concentration of fuel within the hot gas layer varies considerably, with higher concentrations at the ceiling. Concentrations within the flammable range most commonly develop at the interface between the hot gas layer and the cooler air below. Isolated flames (an indicator of a ventilation-controlled fire) are most commonly seen in the lower region of the hot gas layer (as there may be insufficient oxygen concentration in the upper level of the hot gas layer to support flaming combustion). Mixing of the hot gas layer and air due to turbulence increases the likelihood of a significant fire gas ignition.

• What was the ventilation profile and air track when the engine company reached the top of the stairs to begin their attack on the fire?
• How did the tactical ventilation performed from the exterior (removal of the window on floor 2, Side C) influence the ventilation profile and air track?
• What effect do you think that continuous operation of the 30^o fog stream had on conditions on floor 2?
• What combination of factors likely resulting in mixing of air and smoke (fuel) leading to the fire gas ignition that drove the fire attack crew off floor 2 and into the stairwell?

Key Considerations and Lessons Learned

This incident points to a number of key considerations and lessons learned.

• Beware the routine incident! Even what appears to be a simple fire in a small residential structure can present significant challenges and threats to your safety.
• Use the B-SAHF indicators to read the fire and consider both the stage of fire development and burning regime (fuel or ventilation-controlled) in strategic and tactical decision making.
• Flame showing is just that. Do not be lulled into a false sense of security by thinking that the fire is adequately ventilated. Read the air track indicators!
• Continue to read the fire after making entry. Smoke is fuel and hot gases overhead are a threat. Observation of isolated flames indicates a ventilation-controlled fire. Rollover often precedes flashover. Take proactive steps to mitigate the threat of extreme fire behavior.
• Recognize that ventilation-controlled fires will increase in heat release rate if additional air is introduced. Manage the ventilation profile using tactical ventilation and tactical anti-ventilation. Anticipate unplanned ventilation due to fire effects.
• Recognize that both horizontal and vertical ventilation are effective when used appropriately and coordinated with fire control. Consider the influence of inlet and exhaust opening location and size when anticipating the influence of tactical ventilation on fire behavior and conditions within the building.

Again special thanks to Captain Shane Hunter and the Omaha Fire Department for sharing the information about this incident and their work to improve firefighter safety.

Ed Hartin, MS, EFO, MIFireE, CFO

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. While video provides the opportunity to observe fire behavior indicators over time, still photos also an excellent tool for practice your skill in reading the fire.

Smoke Showing Photography

This Reading the Fire exercise is based on a photo taken by Scott LaPrade, a firefighter assigned to Ladder 1 in Leominster, Massachusetts. Scott has been photographing fires around New England for 25 years. His website, Smoke Showing Photography is an excellent resource when looking for fire photos to practice reading the fire.

Apartment Fire

On February 6, 2009, the Leominster Fire Department received a call for smoke in the building at 77 Cedar Street. Ladder 1 was first due and reported smoke showing from a three-story wood frame apartment building originally built in the 1900s.

Initially light smoke was showing from the roof, but then appeared to dissipate. After companies made entry to investigate, the fire progressed rapidly.

Download and print the B-SAHF Worksheet. Consider the information provided above and examine the following photo. First, describe what you observe in terms of the Building, Smoke, Air Track, Heat, and Flame Indicators. Second, answer the following six questions:

1. What stage(s) may the fire be in (incipient, growth, fully developed, or decay)?
2. What burning regime is the fire likely to be in (fuel or ventilation controlled)?
3. What conditions would you expect to find inside the doorway in the photo?
4. What hazards does the firefighter in does the firefighter in the photo face while working in the doorway?
5. How could these hazards be mitigated?
6. If the fire is on Floor 1 (it was), what are likely avenues for extension in this type of building construction?

Note the kink in the 1-3/4″ (45 mm) hoseline behind the firefighter. Kinks can dramatically reduce flow rate. Watch your hoseline as well as the B-SAHF indicators!

Visit Scott’s website Smoke Showing Photography for additional photos of this incident and extend your practice in Reading the Fire.

Ed Hartin, MS, EFO, MIFireE, CFO

25 Years Later

Firefighters Scott Smith and William Duran died as a result of flashover during a search and rescue drill in Boulder, Colorado on January 26, 1982 (Demers Associates, 1982, August). This incident has particular significance in that it was one of the major influences in the development of National Fire Protection Association (NFPA) Standard 1403 Live Fire Training Evolutions in Structures (NFPA, 1986). 25 years after the deaths of the two firefighters in Boulder, rapid fire progress during live fire training claimed the life of Firefighter Paramedic Apprentice Rachael Wilson in Baltimore, Maryland (Shimer, 2007; NIOSH, 2008)

What makes this even more tragic is that unlike the incident in Boulder, for the last 20 years the fire service has had a national consensus standard that defines minimum acceptable practice for live fire training.

Training Exercise on South Calverton Road

Information on the incident that resulted in the death of Firefighter Paramedic Apprentice Rachael Wilson was drawn from the Independent Investigation Report: Baltimore City Fire Department Live Fire Training Exercise 145 South Calverton Road February 9, 2007 (Shimer, 2007) and NIOSH Death in the Line of Duty Report F2007-09 (NIOSH, 2008).

On February 9, 2007 twenty-two members of Baltimore City Fire Department Firefighter Paramedic Apprentice Class 19 were participating in live fire training in an acquired structure. The objectives of this training exercise included practice in fire attack, primary search, forcible entry, and ventilation. The building used for this training exercise was a three story, single family row house of ordinary (masonry and wood joist) construction. The building was of somewhat unusual design with the front (A Side) of the building constructed at an angle (parallel to the street) resulting in a trapezoidal floor plan as illustrated in Figure 1. The third floor was considerably smaller than the first two floors with third floor windows on Side C looking out over the second floor roof. The building had previously been used for training and ceilings and portions of the walls on the second and third floors had been opened up during ventilation and forcible entry practice.

Five instructors assigned to the Training Academy and six adjunct instructors were responsible for managing the live fire training exercise and providing instruction. Lieutenant Crest (Training Academy staff) served as Incident Commander and Division Chief Hyde served as the Safety Officer. Two instructors were assigned as the ignition team and others were assigned to supervise assigned crews of Firefighter Paramedic Apprentices. An engine and truck from the Training Academy were positioned on the A Side of the building. The engine was supplied by a hydrant through a single large diameter hoseline.

The plan for the training exercise called for eight separate fuel packages on Floors 2 (two fuel packages) and 3 (six fuel packages) to be ignited. Each fuel package consisted of one or three pallets and excelsior (soft shredded wood packing material). Crews would be assigned to fire attack on floors two and three while other crews performed forcible entry (in support of fire attack) primary search, ventilation. The trainees were divided into five companies, designated Engine 1 (fire attack on Floor 3), Engine 2 (fire attack on Floor 2), Truck 1 (placement of ladders and then search and rescue), Truck 2 (assist with forcible entry on Side C), and Truck 3 (vertical ventilation). While the Incident Commander outlined the plan for the instructors, the trainees were not provided with a walkthrough of the building or safety briefing prior to the start of the live fire exercise.

The Incident Commander (Lieutenant Crest) accompanied the ignition team into the building and supervised ignition of the fires on Floors 3 and 2. While none of the instructors indicated doing so, a fire was also lit in debris (three mattresses, automobile tire, upholstered chair, and other combustible materials) located just inside the doorway on Floor 1 Side C.

Fire Attack

The crew designated Engine 1 consisted of Emergency Vehicle Driver Wenger (Instructor) and Firefighter Paramedic Apprentice Wilson (nozzle), Paramedic Cisneros (2^nd on the line), and Firefighter Paramedic Apprentices Perez, and Lichtenberg. Engine 1 was tasked with fire attack on Floor 3. None of the crew from Engine 1 was equipped with a portable radio and received their orders face-to-face from Command. When the instructor questioned passing the fire on Floor 2, Command indicated that another line would be coming in right behind them and to go directly to Floor 3. Engine 1 entered from Side A with a 1-3/4″ (45 mm) hoseline and proceeded up the interior stairwell. None of the members of this crew indicated seeing fire on Floor 1 at the time they made entry.

Figure 1. Baltimore Floor Plan.

Note: Adapted from City of Baltimore.  Independent investigation report: The Baltimore city fire department live fire training exercise 145 South Calverton Road February 9, 2007, (Shimmer, 2007, pp. 13)

Upon reaching Floor 2, Engine 1 encountered severe fire conditions and the instructor did not feel comfortable proceeding to Floor 3 without controlling the fire on Floor 2. He instructed Apprentice Wilson to open the nozzle and put water on the fire. In the process of doing so, she fell and the instructor took over the nozzle. He (the instructor) knocked the fire down to the point where he felt that his crew could advance to Floor 3 (bud did not completely control or extinguish the fire on Floor 2). At this point he returned the nozzle to Wilson. Wilson and Cisneros and the instructor proceeded to Floor 3 while Perez, and Lichtenberg remained in the stairwell pulling hose.

Trapped Above the Fire

After reaching Floor 3, Cisneros (2^nd on the line behind Wilson) advised the instructor that Floor 2 was well involved. He instructed her to go into the stairwell and pull up additional hose. She felt intense heat on her legs and advised the instructor that she needed to get out of the building. The instructor climbed through the egress window (see Figure 2) and assisted Cisneros out the window and onto the second floor roof. At this point, Wilson was maintaining a position at the egress window (located at the top of the stairwell) with the nozzle.

Figure 2. Baltimore Cross Section of Floor 3

Note: Adapted from City of Baltimore. Independent investigation report: The Baltimore city fire department live fire training exercise 145 South Calverton Road February 9, 2007, (Shimmer, 2007, pp. 13 & 21-27)

While Engine 1 was making their way to Floor 3, Engine 2 entered from Side C with a 1-3/4″ (45 mm) hoseline, intending to proceeding to Floor 2 as ordered, but encountered a significant fire on Floor 1 with flames beginning to roll across the ceiling. Engine 2 attacked the fire on Floor 1 (which delayed their advancement to Floor 2).

Perez and Lichtenberg (members of Engine 1’s crew pulling hose in the stairwell) felt a rush of air followed by flames rapidly extending up the stairwell from Floor 2 to Floor 3. They moved to the top of the stairs and observed Wilson trying to climb through the egress window. Wilson warned them to get out of the building. Heeding her warning, they proceeded down the stairway with the hoseline and controlled the fire on Floor 2 sufficiently to permit them to exit the building, meeting the crew of Engine 2 who were making their way to Floor 2.

Wilson advised Wenger (instructor with Engine 1) that she needed to get out. She had dropped the nozzle (still operating) and was trying to climb out the window. Wenger tried unsuccessfully to pull her out the window (note the height of the window sill in Figure 2). Wenger asked Wilson if she could help him get her out the window. She replied that she could not and that she was burning up. Wenger lost his grip on Wilson and she fell back into the building. Regaining his grip he pulled her partially out the window again, noticing that her breathing apparatus facepiece was partially displaced. Wenger called for help (shouting as he had no radio). Three members of Truck 3 who were working on the third floor roof dropped down to the second floor roof to assist, but were unable to pull Wilson from the window.

Emergency Vehicle Driver Hiebler (instructor with Engine 2) heard a commotion on Floor 3. He ordered one of his crew to accompany him to Floor 3 with the hoseline and the others to remain in place on Floor 2. Reaching Floor 3, they observed Wilson at the window and Wenger (instructor from Engine 1) working from the second floor roof trying unsuccessfully to pull her out the window. Concerned about the fire on Floor 3, Hiebler instructed the trainee to extinguish the fire while he assisted in getting Wilson out the window.

Wilson was unconscious, pulseless and apnic when she was removed from Floor 3. Her breathing apparatus and protective clothing was removed and cardio pulmonary resuscitation (CPR) was initiated while she was on the second floor roof. At the Incident Commander’s direction she was moved up to the third floor roof so that she could be brought down an aerial ladder that had been placed to the roof from Side A. Prior to being brought down from the third floor roof, Wilson was packaged on a backboard and placed in a stokes basket. On reaching the ground advanced life support medical care was initiated and Wilson was transported to the local trauma center where she was pronounced dead. Firefighter Paramedic Apprentice Rachael Wilson died as a result of thermal injuries and asphyxia.

The Aftermath

The initial investigation of this incident was conducted by the Baltimore City Fire Department, Baltimore City Police Department Arson Unit, and United States Bureau of Alcohol Tobacco and Firearms. Subsequently, Mayor Sheila Dixon commissioned an independent investigation into the circumstances surrounding the death of Rachael Wilson lead by Deputy Chief Chris Shimer of the Howard County Department of Fire and Rescue Services. This investigation concluded that there were in excess of 50 deviations from accepted practice as defined by National Fire Protection Association (NFPA) 1403 Standard on Live Fire Training Evolutions (2002). In addition, the investigators identified significant issues related to the organizational culture of the Baltimore City Fire Department that resulted in a lack of accountability compliance with accepted safety practices (Shimer, 2007)

The Maryland Department of Labor, Licensing, and Regulation cited the Baltimore City Fire Department for 33 safety violations and singled out the fire officers who served as Incident Commander and Safety Officer for the haphazard planning and execution of this live fire training exercise (Linskey, 2007a)

The Baltimore City Fire Department fired Training Division Chief Kenneth Hyde who was the Safety Officer and senior fire officer present at the fatal incident. Citing negligence and incompetence in their roles as Incident Commander (Crest) and supervisor of the rapid intervention team (Broyles) during this incident (Linskey, 2007b) Lieutenants Joseph Crest and Barry Broyles were also terminated.

Following votes of no confidence from the Baltimore City Firefighters and Fire Officers unions and continuing criticism, Fire Chief William Goodwin resigned in November 2007, ten months after the death of Firefighter Paramedic Apprentice Rachael Wilson (Fritze & Reddy, 2007)

Now What?

Rachael Wilson’s death was the result of a complex web of contributing factors. It is easy to say that failure to comply with the provisions of standards and regulations regarding live fire training was the problem. But it is more complex than that.  It is essential that we examine our organizational culture and training practices on an ongoing basis and ask hard questions regarding the safety and effectiveness of what we do.

Ed Hartin, MS, EFO, MIFireE, CFO

References

Demers Associates. (1982, August) Two die in smoke training drill. Fire Service Today, 17-63.

Fritze, J. & Reddy, S. (2007) City’s fire chief resigns. Retrived June 5, 2008 from http://baltimoresun.com/recruit

Linsky, A. (2007c) Baltimore fire department cited in cadet’s death. Retrieved June 4, 2008 from http://baltimoresun.com/recruit

Linsky, A. (2007d) City dismisses two more fire officials. Retrieved June 4, 2008 from http://baltimoresun.com/recruit

National Fire Protection Association. (1986). Standard on live fire training evolutions in structures. Quincy, MA: Author.

National Fire Protection Association. (2002). Standard on live fire training. Quincy, MA: Author.

National Institute for Occupational Safety and Health (NIOSH). (2002). Death in the line of duty, F2007-09. Retrieved February 19, 2009 from http://www.cdc.gov/niosh/fire/pdfs/face200709.pdf

Shimer, R. (2007) Independent investigation report: Baltimore city fire department live fire training exercise 145 South Calverton Road February 9, 2007. Retrieved February 19, 2009 from http://www.firefighterclosecalls.com/pdf/BaltimoreTrainingLODDFinalReport82307.pdf.

This is the first of a series of posts that will examine the events and circumstances surrounding the death of a Firefighter Paramedic Apprentice in Baltimore Maryland in 2007. Unfortunately many of the factors involved in this incident are not unique, but are common to many live fire training fatalities that have occurred over more than 25 years.

Last Monday marked the second anniversary of the death of Firefighter Paramedic Apprentice Rachael Wilson. The death of this young mother in Baltimore, Maryland during live fire training on February 9, 2007 raised many questions.

The investigations conducted by the Baltimore City Fire Department, an independent commission appointed by the Mayor of Baltimore (Shimer, 2007), and National Institute for Occupational Safety and Health (2008) determined that this training exercise was not conducted in compliance with National Fire Protection Association (NFPA) 1403 Standard on Live Fire Training in Structures (2002).  But does this answer the question of how this happened or why Rachael Wilson died? I contend that lack of compliance with existing standards provides only a partial answer.

Historical Perspective

It is unknown exactly when fire service agencies began the practice of live fire training to develop and maintain skill in interior firefighting operations. However, it is likely that firefighter fatalities have occurred during this type of training activity since its inception

Two Firefighters Die in Fire Training Flashover – On January 26, two firefighters died from burns and smoke inhalation during a search and rescue drill held in a vacant single story building (Demers Associates, 1982, August).

Two Firefighters Die in Fire Training Flashover – On July 30, two firefighters died from burns and smoke inhalation during a search and rescue drill held in a vacant single story building (National Institute for Occupational Safety and Health, 2003)

At first glance, the only difference between these two incidents is the month and day of occurrence. However, a major difference between these two tragic events is that the first occurred in Boulder, Colorado in 1982 while the second occurred 20 years later in Kissimmee, Florida in 2002. Five years later a similar story is repeated with the death of Firefighter Paramedic Apprentice Rachael Wilson.

This comparison provides a dramatic example of the limited impact that existing live fire training policy has had on the safety of individuals participating in this essential training activity. This observation is not to minimize the important guidance provided by NFPA 1403 (2007), but to point to several limitations in the scope of this standard and examining this critical type of training activity simply from a reactive, rules based approach.

A fire in a structure presents complex and dynamic challenges. Firefighters are faced with the need to protect the lives of the building occupants as well as their own while controlling the fire and protecting the uninvolved areas of the structure and its contents. Structure fires develop quickly requiring decision-making and action under extreme time pressure. These conditions require a high level of situational awareness and decision-making skill that is dependent on recognition of complex patterns of information presented by the fire environment (Klein, 1999; Klein, Orasanu, Calderwood, & Zsambok, 1995).

Firefighters learn their craft through a mix of classroom and hands-on training. A majority of skills training is performed out of context (i.e. no smoke or fire) or in a simulated fire environment (i.e. using non-toxic smoke). However, this alone does not prepare firefighters to operate in the heat and smoke encountered in an actual structure fire nor to develop critical decision-making skills. Developing this type of expertise requires live fire training!

Live fire training presents the same types of hazards encountered during emergency response operations. However, as a planned activity, training requires a higher standard of care to ensure the safety of participants. This is consistent with standard risk management practices in firefighting operations outlined by Chief Alan Brunacini (2002).

• We will risk our lives a lot, in a calculated manner to save savable lives.
• We will risk our lives a little, in a calculated manner to save savable property.
• We will not risk our lives at all for lives or property that are already lost.

This perspective on risk management is commonly accepted throughout the fire service in the United States. Live fire training parallels the second element of the risk management profile: We will risk our lives a little in a calculated manner to develop competence in structural firefighting operations.

NFPA 1403

In 1986, the National Fire Protection Association first published NFPA 1403 Standard on Live Fire Training. This important standard has been updated and revised five times since its inception. Often, revisions reflect the conditions and actions surrounding the deaths of firefighters during live fire training since the last revision.

Detailed review of the latest revision of NFPA 1403 (National Fire Protection Association, 2007) shows little substantive change in areas that potentially have the most impact on firefighter safety. The 2007 edition of this standard prohibits location of fires in designated exit paths (a reasonable idea) and increases emphasis on the responsibility of the instructor-in-charge, stating: “It shall be the responsibility of the instructor-in-charge to coordinate overall acquired structure (or training structure) fireground activities to ensure correct levels of safety.” While this too is a reasonable idea, what exactly is the “correct level of safety” and how is the instructor-in-charge to coordinate this effort?

NFPA 1403 (National Fire Protection Association, 2007) places specific emphasis on addressing unsafe acts and conditions directly connected to accidents that have occurred during live fire training (e.g., removal of low density fiberboard, prohibiting the use of flammable liquids except under specific conditions, prohibiting fires in exit paths and use of live victims). However, it does not explicitly address the primary causal factor influencing traumatic fatalities during live fire training. Most firefighters who die from traumatic injuries during live fire training die as a result of human error, often on the part of the individuals charged with ensuring their safety, the instructors. Reducing the risk of error requires both technical proficiency and competence in leadership, communication, and teamwork (i.e., crew resource management).

Learning from the Past

Unfortunately many firefighters and fire officers have not heard of Firefighters Scott Smith and William Duran (Boulder Fire Department), Lieutenant  John Mickel and Firefighter Dallas Begg (Osceola County Fire-Rescue), and Rachael Wilson (Baltimore City Fire Department).

In each of the incidents that resulted in firefighter fatalities during live fire training, those involved did not intend for it to happen. The purpose of live fire training is to develop the knowledge and skills necessary to safely and effectively engage in firefighting operations. Firefighters Scott Smith and William Duran died before the development of national consensus standards on safe practices for live fire training. In other cases the instructors and other participants were unaware of the standard or lacked detailed knowledge of how it should be applied. But in each case where firefighters were caught by rapid fire progress, they did not understand fire behavior and practical fire dynamics.

Subsequent posts will examine the incident in which Rachael Wilson lost her life, the lessons that can be learned from live fire training fatalities, and action steps we can take to reduce the risk to participants while conducting realistic and effective live fire training.

Ed Hartin, MS, EFO, MIFireE, CFO

References

Brunacini, A. (2002). Fire command (2nd ed.). Quincy, MA: National Fire Protection Association.

Demers Associates. (1982, August) Two die in smoke training drill. Fire Service Today, 17-63.

Klein, G. A. (1999). Sources of power. Cambridge, MA: MIT Press.

Klein, G. A., Orasanu, J., Calderwood, R., & Zsambok, C., E. (Eds.). (1995). Decision making in action: Models and methods. Norwood, NJ: Ablex.

National Fire Protection Association. (2002). Standard on live fire training. Quincy, MA: Author.

National Fire Protection Association. (2007). Standard on live fire training. Quincy, MA: Author.

National Institute for Occupational Safety and Health. (2003). Death in the line of duty (Report Number F2002-34). Retrieved February 16, 2009, from http://www.cdc.gov/niosh/pdfs/face200234.pdf

National Institute for Occupational Safety and Health. (2008). Death in the line of duty (Report Number F2007-09). Retrieved February 16, 2009, from http://www.cdc.gov/niosh/fire/pdfs/face200709.pdf

Shimer, R. (2007) Independent investigation report: Baltimore city fire department live fire training exercise 145 South Calverton Road February 9, 2007. Baltimore, MD: City of Baltimore.

The previous post (Shielded Fires) examined US Navy research on the effectiveness of different nozzle techniques when dealing with shielded fires conducted on the ex-USS Shadwell, the US Navy full scale damage control research facility (see Figure 1).

Figure 1. USS Shadwell

The researchers tested two different methods for controlling flaming combustion overhead while moving from the entry point to a location in a compartment where firefighters could make a direct attack on the seat of the fire. The first method involved use of a straight stream or narrow fog pattern and the second involved the use of a medium (60^o) fog pattern directed upward at a 45^o angle. In both cases, one to three second pulses were used in application of water into the hot gas layer.

US Navy Findings

Analysis of this series of tests resulted in identification of a number of specific findings related to tactics, equipment, and training. Three of these findings were particularly relevant to the differences between straight stream/narrow fog and medium fog applied to control flaming combustion in the upper layer.

• Pulsed application with a medium fog pattern directed upward at a 45^o angle resulted in less disruption of the thermal layer than use of a straight stream/narrow fog pattern.
• Use of a straight stream/narrow fog resulted in production of a large amount of steam. This was attributed to the fact that the hose streams had to be deflected compartment linings.
• Water management is important when controlling fire in the upper layer, particularly when using a straight stream/narrow fog. Excess water will only result in excess steam production.

Discussing the findings, the researchers observed that pulsed application of medium fog appeared to be an effective tactic for controlling flaming combustion in the upper layer. This conclusion is supported by consistent reduction of upper layer temperature over the course of the tests involving use of pulsed application of a medium fog pattern.  Previous concerns that this approach would result disruption of thermal layering and excess steam production appeared to be unfounded. This conclusion is supported by the heat flux data at 0.9 M (7′ 10″) and 2.9 M (3′) above the floor. Disruption of thermal layering is indicated by an upward spike in lower level heat flux or equalization of heat flux at the lower and upper levels.

Questions

Several questions about the outcome of these tests were posed at the end of the Shielded Fires post.

• Why did the application of water in a straight stream/narrow fog pattern fail to effectively control flaming combustion in the upper layer?
• Why did the upper layer temperature fluctuate when a straight stream/narrow fog was used?
• Why did the upper layer temperature drop consistently when a medium angle fog pattern was used?
• How did the heat flux measurements correlate with the upper layer temperatures in these two tests?
• What are the implications of the heat flux data recorded during these tests on tenability within the compartment for both firefighters and unprotected occupants?

Water converted to steam on contact with compartment linings or other hot objects cools the surfaces. This indirectly lowers gas layer temperature as the hot gases will continue to transfer heat to compartment linings and other cooler objects in an attempt to equalize temperature. However, the effect on upper layer temperature is limited, minimizing effectiveness of stream application in controlling flaming combustion in the upper layer. In addition, as gas temperature is not significantly reduced, steam produced on contact with hot surfaces is added to the volume of hot gases, resulting in a less tenable environment.

Ineffectiveness of straight stream/narrow fog attack in controlling flaming combustion in the upper layer and the perception of increased steam production with this type of attack likely have a common cause. Conversion of water to steam requires much more energy than simply heating water from ambient temperature to its boiling point. When water changes phase from liquid to gas (steam) while in the hot gas layer, the temperature of the gases is reduced. This has several consequences. First, sufficient reduction in temperature results in extinguishment of flaming combustion. Second, reduction of gas layer temperature causes a proportional reduction in gas volume. As illustrated in Figure 2, if 35% of the water is truned to steam in the hot gas layer, the total volume of steam and hot fire gases is less than the original volume of hot fire gases alone (Särdqvist, 2002). As this is often difficult to understand, I will provide a more detailed explanation of this in a subsequent post.

Figure 2. Gas Temperature and Relative Volume

Note. Adapted from Water and Other Extinguishing Agents (p. 155) by Stefan Särdqvist, 2002, Karlstad, Sweden: Raddningsverket. Copyright 2002 by Stefan Särdqvist and the Swedish Rescue Services Agency.

Production of the same volume of steam can have far different consequences depending on where it is produced (in the hot gas layer versus on contact with hot surfaces!

Total heat flux includes energy transferred through radiation, convection, and conduction. However, in these full scale fire tests, radiant and convective heat transfer was most significant. Radiant heat transfer is dependent on the temperature of upper layer gases and flaming combustion. Convective heat transfer is dependent on gas temperature, movement of hot gases, and moisture. Reduction in upper layer temperature while maintaining thermal layering minimizes total heat flux at the lower level where firefighters are working.

Other Considerations

These tests were conducted on a ship (see Figure 1) with most of the compartment linings being metal (rather than gypsum board, plaster, or wood as typically encountered in buildings. The fire compartment did not have windows or other ventilation openings that may exist in more typical buildings encountered by structural firefighters. These differences are significant, but do not diminish the importance of the results of these tests and findings by the researchers.

These tests provide substantive evidence in support of the effectiveness of water converted to steam in the hot gas layer (as opposed to on surfaces) in controlling flaming combustion in the hot gas layer. However, this does not diminish the importance of direct application of water onto burning fuel in a direct attack to complete the process of extinguishment.

Reference

Särdqvist, S. (2002). Water and other extinguishing agents. Karlstad, Sweden: Swedish Rescue Services Agency.

Scheffey, J., Siegmann, C., Toomey, T., Williams, F., & Farley J. (1997) 1994 Attack Team Workshop: Phase II-Full Scale Offensive Fog Attack Tests, NRL/MR/6180-97-7944. Washington, DC: United States Navy, Naval Sea Systems Command

Remember the Past

In Myth of the Self-Vented Fire I pointed out that every week represents the anniversary of the death of one or more firefighters as a result of extreme fire behavior. Some firefighters have heard about these incidents, but many have not. In an ongoing effort to encourage us to remember the lessons of the past and continue our study of fire behavior, I will occasionally be including brief narratives and links to NIOSH Death in the Line of Duty reports and other documentation in my posts.

February 11, 1998 – 1030
Firefighter Paramedic Patrick Joseph King
Firefighter Anthony E. Lockhart
Chicago Fire Department, Illinois

Firefighter King and Firefighter Lockhart responded on different companies to a report of a structural fire in a tire shop. No visible fire was encountered, there was no excessive heat, and only light smoke was found in most of the building with heavier smoke in the shop area. Ten firefighters were in the interior of the structure when an event that has been described as a flashover or backdraft occurred. The firefighters were disoriented by the effects of the backdraft. Some were able to escape but Firefighter King and Firefighter Lockhart were trapped in the structure. A garage door that self-operated due to fire exposure may have introduced oxygen into the fire area and may have been a factor in the backdraft. The exit efforts of firefighters were complicated by congestion in the building. Within minutes of the backdraft, the building was completely involved in fire and rescue efforts were impossible. Both firefighters died from carbon monoxide poisoning due to inhalation of smoke and soot. Further information related to this incident can be found in NIOSH Fire Fighter Fatality Investigation 98-F-05.

February 9, 2007
Firefighter-Paramedic Apprentice Racheal Michelle Wilson
Baltimore City Fire Department, Maryland

Firefighter Wilson and the members of her fire academy class were attending a live fire training exercise in a vacant rowhouse in Baltimore.

Firefighter Wilson was assigned to a group of apprentices and an instructor designated as Engine 1. Her group advanced a dry attack line into the structure. As they climbed the stairs, the line was charged. Engine 1 encountered and extinguished fire on the second floor but did not check the rest of the second floor for fire prior to proceeding to the third floor. On the third floor, they again encountered and began to extinguish fire.

Fire conditions began to worsen with a marked increase in smoke and heat that appeared to be coming from the second floor. Engine 1 firefighters who were on the stairs began to receive burns from the fire conditions. The instructor for Engine 1 climbed out a window at the top of the stairs and helped one burned firefighter escape to the roof.

Firefighter Wilson appeared at the window in obvious distress and attempted to escape. The windowsill was unusually high (41 inches) and she was unable to escape. Firefighter Wilson momentarily moved away from the window, at which time she advised other firefighters to go down the stairs to escape. When she returned to the window, her SCBA facepiece was off and she was beginning to receive burns. She was able to get her upper body out of the window but she could not make it through. Firefighters on the exterior were unable to pull her through until firefighters were able to gain access on the interior and assist with the effort.

When Firefighter Wilson was pulled to the roof, she was in full cardiac and respiratory arrest. She was immediately removed from the roof and received advanced life support care and transportation to the hospital. She was pronounced dead at 1250 hours. Firefighter Wilson received total body surface burns of 50 percent. The cause of death was listed as thermal burns and asphyxiation.

Further information related to this incident can be found in NIOSH Firefighter Fatality Investigation F2007-09 and the Independent Investigation Report on the Baltimore City Fire Department Live Fire Training Exercise, 145 South Calverton Road, February 9, 2007.

My next post will examine the incident in which Rachael Wilson lost her life in greater detail.

Ed Hartin, MS, EFO, MIFIreE, CFO

Fire control and extinguishment is a fairly straightforward process when water can be applied directly to the burning fuel. In the case of burning ordinary combustibles, the energy required to heat the water to its boiling point and convert it to steam cannot be used to continue the process of pyrolysis and lowers fuel temperature to the point where the fire goes out.

However, this process is complicated when the fire is shielded from direct application of water. Assuming that an offensive strategy is appropriate, there are several options for attacking a shielded fire: 1) Make an indirect attack from the exterior (assuming you can access the involved compartment(s) from an exterior location) or 2) Move inside the building to a point inside the building where a an indirect attack can be made from outside the involved compartment(s), or 3) Move inside to a location where a direct attack can be initiated.

When adequate resources are available offensive attack from the interior addresses both life safety and fire control priorities. Proper hoseline placement and coordination of fire control and ventilation tactics protects civilian occupants and provides a safer work environment for firefighters.

The Ongoing Debate

The topic of fire stream selection (fog versus straight or solid stream) likely generates more energy than a fully developed compartment fire. Firefighters bring a great deal of passion based on experience, knowledge, and ignorance to the discussion.

There is not a single answer to the question of which type of fire steam is best. Fog and straight or solid streams have different performance characteristics and are best suited for different applications. Keep in mind that:

• An effective fire stream puts the appropriate amount of water in the right form and right location to achieve the desired result.
• An efficient fire stream accomplishes this with the smallest volume of water and least water damage.

Understanding the effectiveness and efficiency of fire stream application requires both qualitative and quantitative evidence. Firefighters can observe the effects of fire stream application and make a judgment as to effectiveness and efficiency. However, this understanding can be deepened by scientific examination that measures the impact of fire stream application methods.

US Navy Research

In 1994, the United States Navy conducted a series of tests to investigate the aggressive use of water fog for shipboard firefighting (Scheffey, Siegmann, Toomey, Williams, & Farley, 1997). Prior to this time, shipboard firefighting either involved direct attack with a straight stream or narrow fog pattern or indirect attack from outside the involved compartment. This series of tests compared the use of pulsed application of a medium (60o) fog pattern with use of a straight stream in controlling shielded fires and fire conditions involving high temperature and thick smoke conditions that impeded location of the seat of the fire.

The conditions (heat, smoke, and fire gases) associated with these fire scenarios typically does not prevent initial entry into the fire compartment. However, the extra time that it takes to maneuver within a space to locate and attack the seat of the fire does present a significant threat, primarily due to the stage of the fire. Uncontrolled, these fires may continue grow rapidly, potentially resulting in flashover conditions. This is particularly true where the fire is ventilation limited…and entry by the attack team introduces additional air [emphasis added].

While the Navy is concerned with shipboard firefighting, ventilation controlled, shielded fires are commonly encountered by structural firefighters as well.

Test Conditions

The tests were conducted on the ex-USS Shadwell, the Navy’s full-scale damage control research and development platform and involved several different fire scenarios. This post will examine tests involving Fire Threat 1, a growth stage fire involving multiple fuel packages within a compartment to create a well developed growth stage fire approaching flashover (upper layer temperatures in the range of 400^o-600^o C (752^o-1152^o F)). In addition, obstructions were placed to preclude the possibility of direct attack from the point of entry. Firefighters were required to control flames in the upper layer in order to penetrate deep enough into the compartment to make a direct attack on the fire.

Compartment Size and Configuration: The compartment used for the test was irregularly shaped (see Figure 2) with approximate dimensions of 8.5 M x 5.4 M (28′ x 17′ 7″) for an approximate floor area of 45.9 M² (494 ft²).

Figure 1. Compartment Configuration

Fuel Load: Varied fuel types, including wood (red oak) cribs of varied dimensions, 1200 mm x 2400 mm (4′ x 8′) sheets of particle board (two layers of 6.4 mm particle board nailed together to provide a thickness of 13 mm (0.5″), and cardboard boxes of crumpled newspaper. All of the boxes were 457 mm x 381 mm x 305 mm (18″ x 15″ x 12″) and were taped closed after being loosely filled with newspaper. These fuel packages were distributed between three separate fire areas see (Figure 1).

• Fire Area 1 included a triangular wood crib, three particleboard panels (placed vertically against the compartment walls), and nine cardboard boxes filled with newspaper. Fire in these fuel packages was initiated using 2.8 L (0.5 gallon) of heptanes in a 610 mm (24″) pan.
• Fire Area 2 included a square wood crib and nine cardboard boxes filled with newspaper. Fire in these fuel packages was initiated using 18.9 L (5 gallons) of heptanes in a 914 mm (36″) square pan.
• Fire area 3 included a rectangular wood crib and three particleboard panels (placed vertically against the compartment walls). Fire in these fuel packages was initiated using 2.8 L (0.5 gallon) of heptanes in a 610 mm (24″) pan.

Ventilation Profile: Temperature in the upper layer was monitored using thermocouples. Watertight Doors 2-22-2 and 2-21-2 were used to control the air supply to the fire and maintain consistent temperature conditions and flaming combustion in the hot gas layer for each test. When the attack team entered the compartment, air also entered the fire compartment through the entry point at Joining Door 2-16-0 (see Figure 1).

Tactical ventilation was not used in coordination with fire attack during these evolutions. The only ventilation provided while the attack team was engaged in firefighting operations involved the entry point as both exhaust and inlet opening.

Fire Control Procedures: In each of the tests the fire attack team used a 38 mm (1.5″) hoseline with a combination nozzle delivering 360 L/min (95 gpm) at 700 kPa (100 psi). For the pulsed water fog attack, the nozzle team applied oneto three second pulses with a 60^o fog pattern directed upward at a 45^o angle.  For the straight stream attack, the tactics were the same, but a straight stream or narrow fog pattern was used.

Note: It is important to note that the researchers and Navy firefighters involved in these tests considered a narrow fog pattern and straight stream equivalent within the context of shipboard firefighting. While the characteristics of a narrow fog pattern and straight or solid stream are different, both will penetrate through the hot gas layer and result in conversion of water to steam on contact with compartment linings (rather than within the hot gas layer)

The Tests

Test 14 was performed using traditional straight stream tactics. The nozzle operator applied two pulses with a narrow fog pattern in an attempt to control fire in upper layer. This water application produced a large amount of steam, but failed to control flaming combustion in the hot gases. After application of three more short pulses, the attack team moved to Fire Area 2 (see Figure 1) and commenced a direct attack on the fire in Fire Areas 2 and 3. However, 150 seconds (2 minutes 30 seconds) after commencing fire attack, the fire in Fire Area 1 reignited and flaming combustion in the hot gas layer caused the attack team to withdraw towards the entry point and attempt to regain control of the overhead fire. This was unsuccessful and the attack team withdrew to the entry point. A second attempt was made to enter and control the fire overhead using three long (five second) straight stream application from the doorway. These had minimal effect with continued flaming combustion overhead and involvement of fuel packages in all three fire areas. 420 seconds (seven minutes) after the initial attack, the evolution was terminated.

Test 17 replicated conditions used in Test 14, but pulsed application of a medium (60^o) fog pattern was used to control fire in the upper layer, rather than a narrow fog/straight stream. Immediately after making entry, the nozzle operator applied three short pulses directed upward at a 45^o Angle in the direction of Fire Area 2. The first pulse appeared to cause the flaming combustion to increase in Fire Area 2, but subsequent pulses controlled flaming combustion overhead. Visibility was reduced slightly, but the attack team was able to advance and make a direct attack on the seat of the fire. The fuel packages in Fire Area 1 reignited, but the fire was quickly controlled.

Influence on the Fire Environment

Quantitative data on factors such as upper level temperature and heat flux (heat transfer per unit area) within the compartment were recorded in addition to qualitative observations by the firefighters and researchers involved in the test. Figure 2 illustrates the temperature changes in the fire compartment during Tests 14 (straight stream/narrow fog) and 17 (medium angle fog) attacks.

Figure 2.  Average Upper Layer Temperature: Tests 14 and 17

Total heat flux (e.g., radiant and convective) was recorded 2.4 M (7′ 10″) and 0.9 M (3′) above the floor. Figures 3 and 4 illustrate conditions recorded during Test 14 (straight stream/narrow fog) and Test 17 (medium angle fog).

The dashed gray lines are provided as a point of reference at 20 kW/m2, 12.5 kW/m2, and 4.5 kW/m2. These correspond to heat flux conditions required for rapid auto ignition of ordinary combustibles, sufficient pyrolysis for piloted ignition of ordinary combustibles, and second degree burns to exposed skin within 30 seconds respectively.

Figure 3. Heat Flux Test 14

Figure 4. Heat Flux Test 17

Questions

Based on the information on the US Navy tests presented in this post, consider the following questions:

1. Why did the application of water in a straight stream/narrow fog pattern fail to effectively control flaming combustion in the upper layer?
2. Why did the upper layer temperature fluctuate when a straight stream/narrow fog was used?
3. Why did the upper layer temperature drop consistently when a medium angle fog pattern was used?
4. How did the heat flux measurements correlate with the upper layer temperatures in these two tests?
5. What are the implications of the heat flux data recorded during these tests on tenability within the compartment for both firefighters and unprotected occupants?

More to Follow

My next post will examine the answers to these questions and the conclusions reached by the Navy researchers as a result of this series of tests.

Ed Hartin, MS, EFO, MIFireE, CFO

References

Scheffey, J., Siegmann, C., Toomey, T., Williams, F., & Farley J. (1997) 1994 Attack Team Workshop: Phase II-Full Scale Offensive Fog Attack Tests, NRL/MR/6180-97-7944. Washington, DC: United States Navy, Naval Sea Systems Command

Deliberate Practice

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. As you complete this Reading the Fire exercise, think about what you saw and what you did not see. Did you recognize developing conditions, what might you have missed? Watch the video several times. Remember that deliberate practice is focused on continuous improvement and requires repetition of critical skills.

Residential Fire

Download and print the B-SAHF Worksheet and then view the first 25 seconds of the following video of conditions on Side A of a residential fire. First, describe what you observe in terms of the Building, Smoke, Air Track, Heat, and Flame Indicators. Second, answer the following five questions:

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

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Back the video up to the beginning and then watch the first 45 seconds of the clip. Consider the following questions:

1. What changes in in fire behavior did you observe?
2. What fire behavior phenomena occured? What changes in conditions were the likely cause?
3. How could the crew on the hoseline have mitigated the hazards presented by this change in fire behavior?

After completing the B-SAHF exercise, view the remainder of the video. Safe and effective fireground operations require that firefighters and officers are proficient at reading the fire and managing the fire environment. Developing proficiency requires ongoing deliberate practice.

Ed Hartin, MS, EFO, MIFireE, CFO