Posts Tagged ‘reading the fire’

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

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

Taxpayer Fire

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

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

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

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

Ed Hartin, MS, EFO, MIFireE, CFO

Fifteen years ago tomorrow, three members of the Fire Department of the City of New York (FDNY) lost their lives while conducting search in a three story apartment building located at 62 Watts Street in Manhattan. Captain Drennan and Firefighters Young and Seidenburg were trapped in a stairwell by rapid fire progression that occurred as other companies forced entry into the fire apartment on the floor below.

The Case

This case study was developed using a paper written by Richard Bukowski (1996) of the National Institute for Standards and Technology (NIST) Building and Fire Research Laboratory (BFRL). The FDNY requested the NIST assistance in modeling this incident to develop an understanding of the extreme fire behavior phenomena that took the lives of Captain Drennan and Firefighters Young and Seidenburg.

At 1936 hours on March 28, 1994, FDNY responded to a report of heavy smoke and sparks from a chimney of a three-story apartment building at 62 Watts Street (see Figure 1) in Manhattan. On arrival companies observesd smoke from the chimney, but no other evidence of fire. The first due engine and truck companies stretched a hoseline to the first floor unit and vertically ventilated over the stairwell.

Figure 1. 62 Watts Street-Side A

Working as the inside team of the second due truck company, Captain John Drennan (Ladder 5), Firefighter James Young, and Firefighter Christopher Seidenburg (both detailed from Engine 24 to Ladder 5) went to the second floor to begin primary search of the upper floors. At the doorway to the second floor apartment unit they were trapped by an explosion and rapid fire progression from the first floor apartment up the common stairwell. Both firefighters died within 24 hours as a result of thermal injuries. Captain Drennan survived for 40 days in the burn unit before succumbing to his injuries.

Building Information

The fire occurred in a 6.1 m (20′) x 14 m (46′), 3 � story apartment building of ordinary (Type III) construction, containing four dwelling units (the basement apartment was half below grade). Each unit had a floor area of slightly less than� 81.7 m² (880 ft²). The basement unit had its own entrance and the units on Floors 1-3 were served by a common stairwell on Side D of the building (see Figure 1). Exposure B was an attached building identical to the fire structure. Exposure D was a similar structure. Neither exposure was involved.

Figure 2. Floor Plan-First Floor Apartment

Note: Adapted from Modeling a Backdraft Incident: The 62 Watts St. (NY) Fire.

The building was originally built in the late 1800s and had undergone numerous renovations. Recent renovations involved replacement of plaster and lath compartment linings with drywall over wood studs and lowering of the ceiling height from 2.8 m (9’3″) to 2.5 m (8’4″). All apartments had heavy wood plank flooring. During the latest renovation, windows and doors were replaced and extensive thermal insulation added to increase energy efficiency. The building was originally heated with the use of multiple fireplaces in each apartment. However, most of these had been sealed shut. However, the fireplace in the living room of the first floor apartment (unit of origin) was operable and had a 0.209 m² (2.25 ft²) flue.

All apartments had similar floor plans (differences resulting from location of the stairwell). The floor plan of the first floor apartment (unit of origin) is illustrated in Figure 2. Each apartment consisted of a living room, kitchen, bathroom, and bedroom. The first floor unit had an office constructed within the bedroom.

The structure had a flat roof with a scuttle and skylight over the stairwell.

The Fire

The occupant left the first floor apartment at 1825 hours, leaving a plastic trash bag on top of the gas fired kitchen range (see Figure 2). Investigators deduced that the bag was ignited by heat from the pilot light. Fire extended from the bag of trash to several bottles of high alcohol content liquor located on the counter adjacent to the stove. The fire progressed into the growth stage, involving other fuel packages within the apartment. The apartment was tightly sealed with the only sources of ventilation being the open fireplace flue and minimal normal building ventilation.

Weather Conditions

The weather was 10^o C (50 ^o F) with no appreciable wind.

Conditions on Arrival

On arrival companies observed smoke from the chimney of the apartment building, but no other signs of fire from the exterior.

Firefighting Operations

The outside team from the first due truck went to the roof and opened the scuttle over the stairwell while the first arriving engine company stretched a hoseline to the interior and prepared to make entry into the first floor apartment along with the inside team from the ladder company. Ladder 5 was the second due truck. The inside team from Ladder 5, Captain Drennan, Firefighter Young, and Firefighter Seidenburg, went to the second floor to begin primary search.

When the first due engine and truck forced the door to the first floor apartment they observed a pulsing air track consisting of an inward rush of air followed by an outward flow of warm (not hot) smoke. This single pulsation was followed by a large volume of flame from the upper part of the door and extending up the stairwell.

Figure 3. 3D Cutaway View of 62 Watts Street

Note: Adapted from Modeling a Backdraft: The 62 Watts Street Incident.

The crews working on Floor 1 were able to escape the rapid fire progression, but Ladder 5’s inside team was engulfed in flames which filled the stairwell. Flames extended from the doorway of the first floor apartment through the stairwell and vented out the scuttle opening and skylight. This flaming combustion continued in excess of 6 minutes 30 seconds. The intense fire in the stairwell severely damaged the stairs and melted the wired glass in the skylight.

Questions

The following questions focus on fire behavior, influence of tactical operations, and related factors involved in this incident.

1. Other than smoke and sparks from the chimney, what B-SAHF indicators might have been present and visible from the exterior or at the doorway that may have provided an indication of conditions inside the apartment?
2. What do you make of the observations of the company making entry to the first floor apartment for fire attack? Is this consistent with your understanding of backdraft indicators? Why or why not?
3. What steps can you take when making entry if you suspect that the fire is ventilation controlled? How would this change if you suspected or saw indicators of potential backdraft conditions?
4. Firefighters often identify vertical ventilation when given a scenario where backdraft indicators are present. If there is value (savable people or property) and the fire is on a lower floor (as it was in the Watts Street incident), what tactical options are available to mitigate the hazards of potential backdraft conditions?

Analysis and Computer Modeling

My next post will examine the results of this investigation and how the computer modeling performed by NIST contributes to our understanding of the events that took the lives of Captain Drennan and Firefighters Young and Seidenburg.

Ed Hartin, MS, EFO, MIFIreE, CFO

My last post examined National Institute for Standards and Technology (NIST) tests of wind control devices to mitigate hazards presented during wind driven compartment fires (Fire Fighting Tactics Under Wind Driven Conditions). Heat release rate (HRR)� data from Experiment 1 (baseline test with no wind) and Experiment 3 (wind driven) illustrates the dramatic influence of increasing ventilation to a ventilation controlled fire and even more dramatic impact when increased ventilation is coupled with wind (see Figure 1). This post posed several questions related to the HRR data from these experiments.

Figure 1. Heat Release Rates in Experiments 1 (Baseline) and 3 (Wind Driven)

Note: Adapted from Firefighting Tactics Under Wind Driven Conditions.

Questions

Examine the HRR curves in Figure 1 and answer the following questions:

• What effect did deployment of the wind control device have on HRR and why did this change occur so quickly?
• How did HRR change when the wind control device was removed and why was this change different from when the window was vented?
• What factors might influence the extent to which HRR changes when ventilation is increased to a compartment fire in a ventilation controlled burning regime?

Answers: Application of the wind control device rapidly decreased heat release rate from approximately 19 MW to 5 MW. With the window covered, the fire lacked sufficient oxygen to maintain the higher rate of HRR. As oxygen was quickly consumed (and oxygen concentration was decreased) by the large volume of flaming combustion in the compartments, heat release rate was rapidly reduced.

As with the change in HRR when the window was vented, removal of the wind control device resulted in an extremely rapid increase in HRR as additional oxygen was provided to the ventilation controlled fire inside the structure. In this case, the increase was even more significant with the peak HRR reaching approximately 32 MW. Examination of the oxygen concentration curve provides a hint of why this might have been the case (see Figure 2). The oxygen concentration was higher before the window was vented than when the wind control device was removed. The more rapid and greater rise in HRR is likely a result of the extent to which the fire was ventilation controlled and the available concentration of gas phase fuel. After the wind control device was removed, note that the oxygen concentration increased sharply (which relates to the rapid increase in HRR), followed by a rapid decrease as ventilation was inadequate to maintain that rate of combustion.

Figure 2. Oxygen Concentration in the Bedroom

Note: Adapted from Firefighting Tactics Under Wind Driven Conditions.

Practical Application

The results of the NIST research are extremely interesting to students of fire behavior. However, it is essential that we be able to transform this information into knowledge that has practical application. This gives rise to three fundamental questions:

• How do changes in ventilation influence fire behavior? Note that this is always a concern, not just under wind conditions!
• What impact will wind have if the ventilation profile changes?
• What tactical options will be effective in mitigating hazards presented by extreme fire behavior under wind driven conditions?

It is important to consider air track and the flow path from inlet to exhaust opening and the potential consequences of introducing air under pressure without (or with an inadequate) exhaust opening. Both can have severe consequences!

Tactical Problem

One good way to wrestle with the influence of wind on compartment fire behavior is to put it into a realistic context. In the following tactical problem you will be presented with an incident scenario and a series of questions. Apply what you have learned and consider how you would approach this incident.

Resources: You have what you have! Use your normal apparatus assignment and staffing levels when working through this tactical problem.

Weather Information: Conditions are clear with a temperature of 20^o C (68^o F) and a 24 kph (15 mph) wind out of the Northwest.

Dispatch Information: You have been dispatched to a residential fire at 0700 on a Sunday morning. The caller reported seeing smoke from a house at 1237 Lakeview Drive. After companies go enroute, the dispatcher provides an update that she is receiving multiple calls for a fire at this location.

Conditions on Arrival: Approaching the incident location you observe a moderate volume of medium gray smoke from a wood frame, single family dwelling (most structures in this area are of lightweight construction). Smoke is blowing towards the A/D corner of the structure. As illustrated in Figure 3, smoke is visible from the front entry (window and door) of the house and it appears that smoke is showing from Side C as well. On closer examination, you observe that the upper level of the windows on Side A are stained with condensed pyrolysis products, but are intact.

Figure 3. View from Side A

360^o Reconnaissance: Moving down Side B, you observe a substantial body of fire in the center of the house. Smoke is pushing from around several sliding glass doors on Side B (see Figure 4) and flames are visible in the upper layer. The glass in the sliding doors is blackened and cracked, but is still intact. Smoke is also visible from around a large window on Side B Floor 2. Smoke discharge on Side B is swirling and being pushed up over the roof by the wind.

Figure 4. View from the BC Corner

Proceeding around the structure to Sides C and D, you observe a small amount of smoke pushing out from around the windows on Side D.

Questions: The first set of questions deals with size-up and development of an initial plan of action.

• What B-SAHF indicators do you observe in Figures 2 and 3?
• What stage(s) of fire development is (are) likely to exist in the structure?
• What burning regime is the fire in?
• How is the fire likely to develop in the time that it will take to develop and implement your incident action plan?
• Would you have given orders to your crew (or would they have taken pre-planned standard actions) based on your observation of conditions on Side A (Figure 1)? If so what would have been done? Why?
• Would your action plan have changed based on your observations from the B/C corner? What would you do differently? Why?
• What is your action plan at this point? Do you have sufficient resources? What orders would you give the first alarm companies? What actions would you have your crew take? Why?

Your action plan is dependent on size-up and assessment of incident conditions.� Variation in conditions may result in a change in the priority or sequence of tactical action. Would your action plan have been different if the dispatcher had indicated that the caller was trapped in the house? If it would have, what would you have done differently? Why?

Things to Think About

This tactical problem presents a number of challenges. Click on the link to examine the Floor Plan and then consider the following questions:

• What conditions would firefighters have encountered if they made entry through the door on Side A (front door)? Why?
• How would these conditions have changed if glass in one or more of the sliding doors on Side B had failed after firefighters had made entry? Why?
• What conditions would have resulted if the glass in one or more of the sliding doors on Side B had failed and the door on Side A was not open? Why?
• What options for fire attack and tactical ventilation would have been effective in this situation? Would your choice fire attack and tactical ventilation location, sequence, and coordination have varied based on the report of occupants? Why?
• How did your knowledge of the results of the NIST tests on wind driven fires impact your understanding of this incident? How did this understanding influence your tactical decision-making?

It is important to practice strategic and tactical decision-making. However, it is also important to think about how and why we make these decisions. This meta-learning (learning about our learning) has a significant impact on our professional development and ability to learn our craft.

Remember the Past

As discussed in previous posts, it is important to honor the sacrifices of firefighters who have died in the line of duty and not lose lessons learned as time passes. The following narratives were taken from the United States Fire Administration (USFA) reports on Firefighter Line of Duty Deaths (1994 and 2004).

March 29, 1994
Captain John Drennan, 49, Career
Firefighter James Young, 31, Career
Firefighter Christopher Seidenburg, 25, Career
Fire Department of the City of New York, New York

On March 29, three firefighters trapped in the stairwell of a brownstone were burned when they were enveloped in fire while attempting to force their way through a heavy steel door to a second floor apartment. Captain John Drennan, Firefighter James Young, and Firefighter Christopher Seidenburg of the New York City Fire Department were conducting a search when the hot air and toxic gases that collected in the stairwell erupted into flames as other fire crews forced entry into the first floor apartment where the fire had originated. The fire exhibited characteristics of both a backdraft and a flashover. Firefighter Young, in the bottom position on the stairs, was burned and died at the scene. Firefighter Seidenberg and Captain Drennan were rescued by other firefighters. They were transported to a burn unit with third and fourth degree burns over 50 of their bodies. Seidenburg died the next day. Drennan passed away several weeks later. The fire cause was determined to be a plastic bag left by the residents on top of the stove of the floor apartment.

For additional information on this incident see:

Bukowski, R. (1996). Modeling a backdraft: The 62 Watts Street incident. Retrieved March 14, 2009 from http://fire.nist.gov/bfrlpubs/fire96/PDF/f96024.pdf

March 21, 2003 – 0850
Firefighter Oscar “Ozzie” Armstrong, III, Age 25, Career
Cincinnati Fire Department, Ohio

Firefighter Armstrong and the members of his fire company responded to the report of a fire in a two-story residence. The first fire department unit on the scene, a command officer, reported a working fire.

Firefighter Armstrong assisted with the deployment of a 350-foot, 1-3/4-inch handline to the front door of the residence. Once the door was forced open, firefighters advanced to the interior. The handline was dry as firefighters advanced; the hose had become tangled in a bush.

As the line was straightened and water began to flow to the nozzle, a flashover occurred. The firefighters on the handline left the building and were assisted by other firefighters on the front porch of the residence. All firefighters were ordered from the building, air horns were sounded to signal a move from offensive to defensive operations.

Several firefighters saw Firefighter Armstrong trapped in the interior by rapid fire progress. These firefighters advanced handlines to the interior and removed Firefighter Armstrong. A rapid intervention team assisted with the rescue.

Firefighter Armstrong was severely burned. He was transported by fire department ambulance to the hos�pital where he later died.

The origin of the fire was determined to be a pan of oil on the stove.

For additional information on this incident see:

National Institute for Occupational Safety and Health (NIOSH). (2005). Death in the line of duty report F2003-12. Retrieved March 14, 2009 from http://www.cdc.gov/niosh/fire/pdfs/face200312.pdf

Laidlaw Investigation Committee. (2004)Line of duty death enhanced report Oscar Armstrong III March 21, 2004. Retrieved March 14, 2009� from http://www.iafflocal48.org/pdfs/enhancedloddfinal.pdf

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.

United States Fire Administration (USFA). (1995) Analysis report on firefighter fatalities in the United States in 1994. Retrieved March 14, 2009 from http://www.usfa.dhs.gov/downloads/pdf/publications/ff_fat94.pdf

United States Fire Administration (USFA). (2005). Frefighter fatalities in the United States in 2004. Retrieved March 14, 2009 from http://www.usfa.dhs.gov/downloads/pdf/publications/fa-299.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

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

The Incident

Kernersville Fire Rescue and responded to a residential in the 1300 block of Union Cross Road shortly after 0200 hours on January 14, 2009. Occupants had been evacuated by two civilians returning home from work at a nearby Dell computer plant. First arriving units initiated offensive operations and began primary search to ensure that all occupants were out of the residence.

Less than 15 minutes into initial operations, an explosion occurred resulting in partial collapse of the building. Kernersville Firefighter Jay Coleman and three firefighters from the Winston-Salem Fire Department were caught in the collapse, but were able to self-extricate. Firefighter Coleman suffered minor injuries.

Chief Walt Summerville of Kernersville Fire Rescue reported “as we entered the building and began to ventilate and to flow air by moving hose lines, the heated gases got the air it needed”.� Chief Summerville believes the explosion was a backdraft, which was caused by a build-up of smoke in the crawl space of the home.

Explosion Captured on Video

A Kernersville police officer’s dashboard camera caught a burning home as it suddenly exploded. The police car was (appropriately) positioned a considerable distance from the house and provides a view of Side A from the Alpha/Delta corner. Watch the video several times to get a general sense of what happened Then download and print the B-SAHF Worksheet and identify any key indicators that might have be visible in the video.

Post fire video and an interview with Firefighter Coleman are available on the WGHP Fox Channel 8 web site.

At this point, information available about this incident is limited to news reports and video. However, we will be in touch with Kernersville Fire Rescue in an effort to obtain more detailed and fire behavior focused information about this incident. More to follow!

Important Lessons

An initial look at the limited information available about this incident points to several important considerations:

• Conditions can vary widely in different compartments. In this incident (like many others) flaming combustion is visible in one location, while extremely under-ventilated backdraft conditions exist elsewhere.
• Backdraft can occur in an entire building, one or more habitable compartments, or in a void space.
• Backdraft indicators may be pronounced, they may be subtle, or may not be visible from firefighters working positions.

Ed Hartin, MS, EFO, MIFireE, CFO

Deliberate Practice

As discussed in my posts on Outstanding Performance and Reading the Fire improving proficiency requires sustained 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.

Residential Fire

Download and print the B-SAHF Worksheet and then view the first 45 seconds of the following video of conditions on Side C of a residential fire as the crew of Toronto Pumper 223 makes entry into a window on Floor 2, Side A to check for extension from a fire in the basement. 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. What state(s) of fire development is the fire likely to be in (incipient, growth, fully developed, or decay)? Remember that fire in adjacent compartments can be in a different stage of development?
3. What burning regime is the fire in (fuel or ventilation controlled)?
4. What conditions would you expect to find on Floor 2? Is the environment tenable for properly protected firefighters?
5. Is it likely that the fire has extended to Floor 2? Why or why not?
6. How would you expect the fire to develop over the next two to three minutes

Find more videos like this on firevideo.net

Back the video up to the beginning and then watch the first three minutes of the clip and consider the following questions:

1. What changes in indicators did you observe prior to the egress of the crew of Pumper 223 from Floor 2?
2. What changes in indicators did you observe following their egress from Floor 2?
3. What might have caused the change in conditions while the crew of Pumper 223 was checking for extension
4. Were there significant indicators of worsening fire behavior visible from the exterior prior to the egress of the members working on Floor 2?
5. What indicators of changing conditions would you have expected on the interior of Floor 2?
6. What tactical options might have reduced the probability of developing untenable conditions on Floor 2?
7. Review your answers on the B-SAHF worksheet. Did any of your answers change based on the additional information provided by the second segment of the video clip? Did you successfully predict the fire behavior that occurred?

After completing the B-SAHF exercise, view the remainder of the video. Placement of the tip of the ladder above the window sill made egress from Floor 2 a bit more difficult. However, Captain Mark Fitzsimmons and Firefighters Geoff Mortimer and Mark Ashcroft from Toronto Pumper 223 escaped without serious harm because they recognized changing conditions and quickly made the decision to exit.

As noted in my earlier post on Flashover & Survival Skills it is essential to train on emergency procedures, but it is even more important to ensure that firefighters and officers are proficient at reading the fire and managing the fire environment to reduce the probability that emergency procedures will be required.

Comments Fixed!

Thanks to Dr. Stefan Svensson for alerting me to a problem with the comments feature of the blog. The problem has been fixed and you can now provide feedback on the posts in the CFBT Blog. Please feel free to do so!

Ed Hartin, MS, EFO, MIFireE, CFO

Deliberate Practice

As discussed in my posts on Outstanding Performance and Reading the Fire improving proficiency requires sustained 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.

Commercial Fire

Download and print the B-SAHF Worksheet and then view the first 8 seconds of the following video of conditions on Side C of a commercial 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. What state(s) of fire development is the fire likely to be in (incipient, growth, fully developed, or decay)? Remember that fire in adjacent compartments can be in a different stage of development?
3. What burning regime is the fire in (fuel or ventilation controlled)?
4. What conditions would you expect to find inside this building? Is this likely to be a survivable environment for unprotected occupants? For firefighters?
5. How would you expect the fire to develop over the next two to three minutes?

Find more videos like this on firevideo.net
Back the video up to the beginning, watch the first 15 seconds, and review your answers on the B-SAHF worksheet. Did any of your answers change based on the additional information provided by the view of Side A?
After completing the B-SAHF exercise, view the remainder of the video. Did you successfully predict the fire behavior that occurred? This video provides excellent examples of smoke and air track indicators. However, sometimes the indicators of potential for extreme fire behavior might not be so obvious. Under these circumstances, you will need a higher level of skill to anticipate fire development.

Make it a Habit!

As Geoff Colvin emphasizes in Tallent is Overrated the quantity and quality of deliberate practice is the major determinant in expertise at all levels from novice to expert. Developing skill in reading the fire requires practice. Additional B-SAHF exercises will be posted on a regular basis at cfbt-us.com. Also check the CFBT-US Resources page for additional information on Reading the Fire!

Consider making B-SAHF exercises a regular part of your training schedule. During a recent Compartment Fire Behavior Training (CFBT) Instructor course conducted at Tualatin Valley Fire & Rescue we used B-SAHF drills each morning to help the participants develop skill in reading the fire. However, these drills are equally appropriate for recruit firefighters. Understanding fire behavior and the ability to read the fire and anticipate changes in fire development are critical for everyone working on the fireground!

Ed Hartin, MS, EFO, MIFireE, CFO

Photo by Mark E. Brady, Prince Georges County Fire/EMS Department

Experienced Judgment

Firefighters frequently base their expectations of how a fire will behave on their experience. Wildland fire scientist Harry Gisborne’s1948 observations about wildland firefighters experienced judgment can be paraphrased to apply to structural firefighters as well:

For what is experienced judgment except opinion based on knowledge acquired by experience? If you have fought fires in every type of building with every different configuration and fuel load, under all types of conditions, and if you have remembered exactly what happened in each of these combinations your experienced judgment is probably very good

Unfortunately this is rarely the case. Firefighters and fire officers often have limited experience and do not have sufficient understanding of fire dynamics to recognize potential for extreme fire behavior.

Riverdale Flashover

Two firefighters from the Riverdale Volunteer Fire Department in Prince Georges County Maryland recently were surprised by a flashover in a small, single family dwelling. Probationary Firefighter Tony George captured initial operations in a series of four photos taken over a period of two minutes.

In the first photo, firefighters from Engine 813 and Truck 807 prepare to make entry. Note that the front door is closed, the glass of the slider and windows are darkened, and smoke can be observed in the lower area of the front porch.

• What can be inferred from these observations?
• What is the stage of fire development and burning regime?

Six seconds later it appears that the front door has been opened, flames are visible through the sliding glass door, and the volume of smoke in the area of the porch has increased. However, the smoke is not thick (optically dense).

• Has your perception of fire conditions changed?
• Why did fire conditions change after the door was opened?

Forty eight seconds later, as the crew from Truck 807 makes entry to perform horizontal ventilation the volume of smoke from the front door increases and thickens (becomes more optically dense). The crew from Engine 813 experiences a burst hoseline, delaying fire attack.

• If the fire was ventilation controlled prior to opening the door, how are fire conditions likely to change?
• If the truck crew increases ventilation by opening windows, how will this influence fire development?
• What is the potential impact of the delay in deployment of a hoseline to attack the fire?

Two minutes after the first photo, and shortly after the crew from Truck 807 made entry, flashover occurred.

According to a press release from Prince Georges County Fire/EMS Department Chief Spokesperson Mark Brady:

The engine from Riverdale Heights arrived first and advanced a hoseline to the front door and paused to don their personal protective equipment (PPE) and self contained breathing apparatus (SCBA). The house was vacant and a small fire could be seen in the front living room. The ladder truck from Riverdale Fire/EMS Station #807 was the second to arrive, almost at the same time as Riverdale Heights. The crew from Truck 807 donned their PPE and SCBA and entered the structure to begin ventilation by removing windows. As the engine crew from Riverdale Heights prepared to enter the structure and extinguish the fire their hoseline sustained damage from glass or debris and was cut; rendering it useless. As additional arriving firefighters stretched another hoseline into position, a flashover occurred.

Two firefighters involved in this incident were seriously injured, FF Johnston was treated and released. FF Blazek was admitted to the MedStar Burn unit. Visit the Riverdale Volunteer Fire Department Web Site for updates on FF Blazek’s condition.

Things to Think About

Near misses and injuries such as occurred during this incident happen all too frequently. All too often, firefighters and officers consider this to be part of the job. Fire behavior is extremely predictable. It will do the same thing every single time under the same conditions. The problem is that the conditions are seldom exactly the same and our experienced judgment is not perfect.

What can you do to reduce the risk of being surprised by extreme fire behavior? Become (or continue to be) a student of your craft and develop an improved understanding of fire dynamics and the influence of tactical operations on fire behavior. Practice reading the fire (see my earlier post Reading the Fire: B-SAHF) using photos, video, and every fire you respond to.

Ed Hartin, MS, EFO, MIFireE, CFO