Video of several incidents involving explosions during structural firefighting operations have been posted to YouTube in the last several weeks. Two of these videos, one from New Chicago, IN and the other from Olathe, KS involve residential fires. The other is of a commercial fire in Wichita, KS.
When a video shows some sort of spectacular fire behavior there is generally a great deal of speculation amongst the viewers about what happened. Was it a smoke (fire gas) explosion, backdraft, flashover, or did something else happen? Such speculation is useful if placed in the framework of the conditions required for these phenomena to occur and the Building, Smoke, Air Track, Heat, and Flame (B-SAHF) indicators that provide cues of to current fire conditions and potential fire behavior.
Occasionally, what happened is fairly obvious such as flashover resulting from increased ventilation under ventilation controlled conditions. However, the phenomena and its causal factors are often much more of a puzzle.
Limited information was posted along with this pre-arrival video of a residential fire in Olathe, KS. The home was unoccupied when the fire occurred.
Watch the thirty seconds (0:30) of the video. First, describe what you observe in terms of the Building, Smoke, Air Track, Heat, and Flame Indicators; then answer the following five standard questions (based only on what you observe during the first thirty seconds of the video)?
What additional information would you like to have? How could you obtain it?
What stage(s) of development is the fire likely to be in (incipient, growth, fully developed, or decay)?
What burning regime is the fire in (fuel controlled or ventilation controlled)?
What conditions would you expect to find inside this building?
How would you expect the fire to develop over the next two to three minutes
Watch remainder of the video and consider the following questions:
Did fire conditions progress as you anticipated?
What changes in the B-SAHF indicators did you observe?
What may have caused the explosion (consider all of the possibilities)?
Were there any indications that may have given warning of this change in conditions?
Residential Fire-New Chicago, IN
Companies from New Chicago and Hobart were dispatched to a reported house fire at 402 Madison in New Chicago, IN on February 17, 2012.
Watch the thirty seconds (0:30) of the video. First, describe what you observe in terms of the Building, Smoke, Air Track, Heat, and Flame Indicators; then answer the following five standard questions (based only on what you observe during the first thirty seconds of the video)?
What additional information would you like to have? How could you obtain it?
What stage(s) of development is the fire likely to be in (incipient, growth, fully developed, or decay)?
What burning regime is the fire in (fuel controlled or ventilation controlled)?
What conditions would you expect to find inside this building?
How would you expect the fire to develop over the next two to three minutes
Watch remainder of the video and consider the following questions:
Did fire conditions progress as you anticipated?
What changes in the B-SAHF indicators did you observe?
What may have caused the explosion (consider all of the possibilities)?
Were there any indications that may have given warning of this change in conditions?
Commercial Fire-Wichita, KS
Wichita Fire Department on scene of a working building fire in large, non-combustible commercial building. Extreme heat and fire conditions cause an unknown cylinder to explode.
Keep in mind that gas cylinders and other closed containers can result in explosions during structural firefighting operations. Unlike backdraft and smoke explosion, the only clue may be building factors related to occupancy (and this may not be a good indicator when operating at a residential fire).
Wichita Fire Department on scene of a working building fire in a large metal structure. Extreme heat and fire conditions cause an unknown cylinder to explode. If you listen close, you can hear it vent before it goes off. Concussion actually cuts out my audio for just a couple seconds. No one was injured.
Potential for explosions related to extreme fire behavior such as backdraft and smoke explosion may be recognized based on assessment and understanding the B-SAHF (Building, Smoke, Air Track, Heat, and Flame) indicators. Other types of explosions such as those resulting from failure of closed containers (e.g., containing liquids or gases) may be a bit more difficult as this potential is likely to be present in most types of occupancies. However, commercial and industrial occupancies present greater risks.
Recognizing that even with sound experienced judgment, there may be undetected hazards on the fireground. Managing the risk requires developing a solid knowledge base and skills and operating within sound rules of engagement such as the IAFC Rules of Engagement for Structural Firefighting. However, considering the hazards presented by rapid fire progression and potential for changes in conditions following explosive events, I would add the following:
Base your strategies and tactics on current and anticipated fire behavior and structural stability.
Ensure that members correctly wear complete structural firefighting clothing and SCBA when working in the hazard zone and practice good air management. Buddy check before entry!
Crews operating on the interior should have a hoseline or be directly supported by a crew with a hoseline. If conditions deteriorate, a hoseline allows self-protection and provides a defined egress path.
My next post will address the impact of a closed door on tenability during a residential fire as the ninth tactical implication identified in the UL study on the Impact of Ventilation on Fire Behavior in Legacy and Contemporary Residential Construction.
Subsequent posts will come back to the Olathe, KS and New Chicago, IN residential fires to examine potential impacts on fire behavior and explosions that resulted during these incidents.
Developing and maintaining proficiency in reading the Fire using the B-SAHF (Building, Smoke, Air Track, Heat, and Flame) organizing scheme for fire behavior indicators, requires practice. This post provides an opportunity to exercise your skills using a video segment shot during a commercial fire.
Residential Fire
This post examines fire development during a residential fire in New Chicago, Indiana.
Watch the first 30 seconds (0:30) of the video. First, describe what you observe in terms of the Building, Smoke, Air Track, Heat, and Flame Indicators; then answer the following five standard questions?
What additional information would you like to have? How could you obtain it?
What stage(s) of development is the fire likely to be in (incipient, growth, fully developed, or decay)?
What burning regime is the fire in (fuel controlled or ventilation controlled)?
What conditions would you expect to find inside this building?
How would you expect the fire to develop over the next two to three minutes
In addition, consider how the answers to these questions impact your assessment of the potential for survival of possible occupants.
Now watch the video clip from 0:30 until firefighters make entry at 3:05. Now answer the following questions:
Did fire conditions progress as you anticipated?
What changes in the B-SAHF indicators did you observe?
How do you think that the stage(s) of fire development and burning regime will change over the next few minutes?
What conditions would you expect to find inside this building now?
How would you expect the fire to develop over the next two to three minutes
The crews working in this video appeared to achieve fire control fairly quickly and without incident. However, consider the following tactical and task related questions:
It did not appear that any member of the first arriving companies performed a 360o recon and size-up (they may have, but this was not visible in the video). Why might this be a critical step in size-up at a residential fire?
It appeared that two lines were run simultaneously (the first line to the door ended up as the back-up line, possibly due to a slight delay in charging the line). How should fire attack and backup roles be coordinated?
Fire attack was initiated from the interior (unburned side). What would have been the impact of the first line darkening the fire from the exterior (prior to entry)?
Were there any indicators of potential collapse (partial) of the roof? How would you manage this risk when working in a lightweight wood frame residence with observed extension into the trussloft? What factors would influence your decision-making and actions?
Reading the Fire
See the following posts for more information on reading the fire:
I recently traveled to Peru to deliver a presentation on 3D Firefighting at the First International Congress on Emergency First Response which was conducted by the Cuerpo General de Bomberos Voluntarios del Perú. This congress was being conducted in conjunction with the Peruvian fire service’s 150th anniversary celebration (establishment of Unión Chalaca No. 1, the first fire company).
In addition to my conference presentation, I spent 10 days teaching fire behavior and working alongside the Bomberos of Lima No.4, San Isidro No. 100, and Salvadora Lima No. 10.
Fire & Rescue Services in Lima, Peru
Lima is a city of 8 million people served by a volunteer fire service which provides fire protection, emergency medical services, hazmat response, and urban search and rescue. The stations that I worked in were busy with call volumes from 2000 to 5000 responses in an urban environment ranging from modern high-rise buildings to poor inner city neighborhoods. Each station was equipped with an engine, truck, rescue, and ambulance. Staffing varied throughout the day with some units being cross staffed or un-staffed due to limited staffing. At other times, units were fully staffed (5-6 on engines and trucks, 4 on rescues, and 3 on ambulances). While the Peruvian fire service has some new apparatus, many apparatus are old and suffer from frequent mechanical breakdown. Faced with high call volume and old apparatus and equipment, the Firefighters and Officers displayed a tremendous commitment to serve their community.
The firefighters I encountered had a tremendous thirst for knowledge and commitment to learning. My friend Giancarlo had arranged for a short presentation on fire behavior for a Tuesday evening and the room was packed. Class was scheduled from 20:00 until 22:00. However, when we reached 22:00, the firefighters wanted to stay and continue class. We adjourned at 24:00. This continued for the next two nights. Sunday, between calls, we had breakfast at San Isidro No. 100 and then conducted a hands-on training session on nozzle techniques and hose handling. At the start of class, Firefighter Adryam Zamora from Santiago Apostol No. 134, related that he used the 3D techniques we had discussed in class at an apartment fire the night before with great success.
Staff Ride
Staff rides began with the Prussian Army in the mid-1800s and are used extensively by the US Army and the US Marine Corps. A staff ride consists of systematic preliminary study of a selected campaign or battle, an extensive visit to the actual sites associated with that campaign, and an opportunity to integrate the lessons derived from these elements. The intent of a staff ride is to put participants in the shoes of the decision makers on a historical incident in order to learn for the future. Wildland firefighters have adapted the staff ride concept and have used it extensively to study large wildland fires, fatalities, and near miss incidents. However, structural firefighters have not as commonly used this approach to learning from the past.
When I traveled to Lima, I only knew two Peruvians; Teniente Brigadier CBP (a rank similar to Battalion Chief in the US fire service) Giancarlo Passalaqua and Teniente CBP (Lieutenant) Daniel Bacigalupo. However, I left Lima with a much larger family with many more brothers and sisters.
Backdraft!
Many firefighters have seen the following video of an extreme fire behavior event that occurred in Lima, Peru. This video clip often creates considerable discussion regarding the type of fire behavior event involved and exactly how this might have occurred. Photos and video of fire behavior are a useful tool in developing your understanding and developing skill in reading the fire. However, they generally provide a limited view of the structure, fire conditions, and incident operations.
Note: While not specified in the narrative, this video is comprised of segments from various points from fairly early in the incident (see Figure 3, to later in the incident immediately before, during, and after the backdraft).
When I was invited to Lima, I asked my friend Teniente Brigadier CBP Giancarlo Passalaqua who worked at this incident, if it would be possible to talk to other firefighters who were there and to walk the ground around the building to gain additional insight into this incident.
The Rest of the Story
The morning after I arrived, I was sitting in the kitchen of San Isidro No. 100 and was joined in a cup of coffee by Oscar Ruiz, a friendly and engaging man in civilian clothing who I assumed was a volunteer firefighter at the station. After my friend Giancarlo arrived, he told me that Oscar was actually Brigadier CBP (Deputy Chief) Oscar Ruiz from Lima No. 4 and one of the two firefighters who had been in the bucket of the Snorkel pictured in the video. Oscar and I had several opportunities to spend time together over the course of my visit and he shared several observations and insights into this incident.
At 11:00 hours on Saturday, March 15, 1997, two engines, a ladder, heavy rescue, medic unit, and command officer from the Lima Fire Department were dispatched to a reported commercial fire at the intersection of Luis Giribaldi Street and 28 de Julio Street in the Victoria section of Lima.
Companies arrived to find a well developed fire on Floor 2 of a 42 m x 59 m (138’ x 194’) three-story, fire resistive commercial building, The structure contained multiple, commercial occupancies on Side A (Luis Giribaldi Street) and Side B (28 De Julio Street). Floors 2 and 3 were used as a warehouse for fabric (not as a plastics factory as reported in the video clip). The building was irregularly shaped with attached exposures on Sides B and C.
Exposure A was a complex of single-story commercial occupancies, Exposure B was an attached two-story commercial complex, Exposure C was an attached three story commercial complex, and Exposure D was a three story apartment building. All of the exposures were of fire resistive construction.
Figure 1. Plot Plan
Floors 2 and 3 had an open floor plan and were used for storage of a large amount of fabric and other materials. As illustrated in Figure 1, there were two means of access to Floors 2 and 3; a stairway on Side A and an open shaft and stairway on Side C.
Due to heavy fire involvement, operations focused on a predominantly defensive strategy to control the fire in this multi-occupancy commercial building. The incident commander called for a second, and then third alarm. Defensive operations involved use of handlines and an aerial ladder working from Side A and in the Side A stairwell leading to Floor 2. However, application of water from the ladder pipe had limited effect (possibly because of the depth of the building and burning contents shielded from direct application from the elevated stream.
Figure 2. Early Defensive Operations
Note: Video screen shot from the intersection of Luis Giribaldi and 28 de Julio.
The third alarm at 14:05 hours brought two engines and articulating boom aerial platform (Snorkel) from Lima 4 to the incident. Snorkel 4, under the command of Captain Roberto Reyna was tasked to replace the aerial ladder which had been operating on Side A and operate an elevated master stream to control the fire on Floor 2 (Figure 2).
Placing their master stream into operation Teniente Oscar Ruiz and Captain Roberto Reyna worked to darken the fire on Floor 2. As exterior streams were having limited effect, Snorkel 4 was ordered to discontinue operation and began to lower the bucket to the ground. At the same time, efforts were underway to gain access to the building from Side C. Using forcible entry tools, firefighters breached the large loading dock door leading to the vertical shaft and stairwell in the C/D quadrant of the building.
Prior to opening the large loading dock door on Side C (Charlie/Delta Corner), a predominantly bi-directional air track is visible at ventilation openings on Side C. Flaming combustion from windows on Side A was likely limited to the area at openings with a bidirectional air track. Combustion at openings on Side A likely consumed the available atmospheric oxygen, maintaining extremely ventilation controlled conditions with a high concentration of gas phase fuel from pyrolyzing synthetic fabrics deeper in the building.
The ventilation profile when Snorkel 4 initially began operations included intake of air through the open interior stairwell (inward air track) serving floors 1-3 and from the lower area of windows which were also serving as exhaust openings (bi-directional air track). Interview of members operating at the incident indicates that there were few if any ventilation openings (inlet or exhaust) on Sides B, C, or D prior to creation of an access opening on Floor 1 Side C.
At approximately 15:50, Snorkel 4 was ordered to stop flowing water. As smoke conditions worsened, they did so and began to lower the aerial tower to the ground. At the same time, crews working to gain access to Floor 1 on Side C, breached the large loading dock door. A strong air track developed, with air rushing in the large opening and up the open vertical shaft leading to the upper floors as illustrated in Figure 3.
Figure 3. Layout of Floors 1 and 2
As the Snorkel was lowered to the ground, Teniente Oscar Ruiz observed a change in smoke conditions, observing a color change from gray/black to “phosphorescent yellow” (yellowish smoke can also be observed in the video clip of this incident). Less than two minutes after the change in ventilation profile, a violent backdraft occurred, producing a large fireball that engulfed Captain Roberto Reyna and Teniente Oscar Ruiz in Snorkel 4 (see Figure 4). The blast seriously injured the crew of Snorkel 4 along with numerous other members from stations Lima 4, Salvadora Lima 10, and Victoria 8 who were located in the Stairwell (these members were blown from the building) and on the exterior of Side A.
This incident eventually progressed to a fifth alarm with 63 companies from 26 of Lima’s 58 stations in attendance.
Figure 4. Backdraft Sequence
Watch the video again; keeping in mind the changes in air track that resulted from breaching the loading dock door on Side C. Consider the B-SAHF (Building, Smoke, Air Track, Heat, and Flame) indicators that are present as the video progresses.
Luis Giribaldi Street and 28 de Julio Street Today
The building involved in this incident is still standing and while it has been renovated, is much the same as it was in 1997. On December 6, 2010, Teniente Brigadier Giancarlo Passalaqua, myself and Capitáin Jordano Martinez went to Luis Giribaldi and 28 de Julio to walk the ground and gain some insight into this significant incident.
Figure 5. Luis Giribaldi Street
As illustrated in Figure 5, Luis Giribaldi Street is a one-way street with parking on both sides and overhead electrical utility lines.
Figure 6. A/D Corner
There are a number of obvious structural changes that have been made since the fire. Including installation of window glazing flush with the surface of the building (the original windows can be seen behind these outer windows).
Figure 7. Snorkel 4’s Position
Figure 7 shows the view from Snorkel 4’s position, just to the left of center is the entry way leading to the stairwell used to access Floors 2 and 3. Piled fabric and other materials can be seen through the windows of Floors 2 and 3, likely similar in nature to conditions at the time of the incident.
Figure 8. Side A
Figure 8 provides a view of Side A and Exposure B, which appears to be of newer construction and having a different roofline than the fire building. The appearance of the left and right sides of the fire building are different, but this is simply due to differences in masonry veneer on the exterior of the building.
Figure 9. A/B Corner
Figure 10. Side B
Figure 11. B/C Corner
As illustrated in Figures 10-11 this block is comprised of several attached, fire resistive buildings. It is difficult to determine the interior layout from the exterior as there are numerous openings in interior walls due to renovations and changes in occupancy over time. The floor plan illustrated in Figure 4 is the best estimate of conditions at the time of the fire based on interviews with members operating at the incident.
Figure 12. Side C and the Loading Dock Door
Figure 12shows Side C of the fire building and Exposure C and the loading dock door that was breached to provide access to the fire building from Side C immediately prior to the backdraft.
Figure 13. Side D and Exposure D
Figure 13illustrates the proximity of Exposure D, a three-story, fire-resistive apartment building.
Lessons Learned
This incident presented a number of challenges including a substantial fuel load (in terms of both mass and heat of combustion), fuel geometry (e.g., piled stock), and configuration (e.g., shielded fire, difficult access form Side C). Analysis of data from the short video clip and discussion of this incident with those involved provides a number of important lessons.
Knowledge of the buildings in your response area is critical to safe and effective firefighting operations. While a challenging task, particularly in a large city such as Lima, developing familiarity with common building types and configurations and pre-planning target hazards can provide a significant fireground advantage.
Reading the fire is essential to both initial size-up and ongoing assessment of conditions. In this incident, fire behavior indicators may have provided important cues needed to avoid the injuries that resulted from this extreme fire behavior event.
Some fire behavior indicators can be observed from one position, while others may not. It is particularly important that individuals in supervisory positions be able to integrate observations from multiple perspectives when anticipating potential changes in fire behavior.
Any opening, whether created for tactical ventilation or for entry has the potential to change the ventilation profile. It is important to consider potential changes in fire behavior that may result from changes in ventilation (particularly when the fire is ventilation controlled).
Communication and coordination are critical during all fireground operations. It is essential to communicate observations of key fire behavior indicators and changes in conditions to Command. Tactical ventilation (or other tactical operations that may influence fire behavior) must be coordinated with fire attack.
Protective clothing and self-contained breathing apparatus are a critical last line of defense when faced with extreme fire behavior (even when engaged in exterior, defensive operations).
I would like to recognize the members of the Peruvian fire service who assisted in my efforts to gather information about this incident and identify the important lessons learned. In particular, I would like to thank Teniente Brigadier Giancarlo Passalaqua, Brigadier CBP Oscar Ruiz, and my brothers at Lima 4 who generously shared their home, their time, and their knowledge.
Ed Hartin, MS, EFO, MIFIreE, CFO
When I was invited to Lima, I asked my friend Teniente Brigadier CBP Giancarlo Passalaqua who worked at this incident, if it would be possible to talk to other firefighters who were there and to walk the ground around the building to gain additional insight into this incident.
Greetings from Peru! I am writing this post in the kitchen of Station #100 in San Isidro, which is one of the districts in Lima. I am in Lima to speak on the concepts of practical fire dynamics and 3D Firefighting at a fire and rescue conference later in the week.
I would like to extend special thanks the Station Chief Paul Zarak and the members of Station 100 for making me welcome in their house. Paul and my friend Daniel Bacigalupo of Lima Station 4 picked me up at the airport and provided me with a great welcome to the Peru and the City of Lima.
Reading the Fire-The Journey Continues
Developing and maintaining proficiency in reading the Fire using the B-SAHF (Building, Smoke, Air Track, Heat, and Flame) organizing scheme for fire behavior indicators, requires practice. This post provides an opportunity to exercise your skills using a video segment shot during a fire in a detached garage. While a fairly simple incident, remember that the description of many tragic events begin with the words “it appeared to be a routine incident”. There are no routine incidents
This post examines fire development during a fire in a detached garage with an exposed dwelling on Side C which occurred in Lake Station, Indiana. The video begins prior to the start of firefighting operations.
Watch the first 25 seconds (0:25) of the video. First, describe what you observe in terms of the Building, Smoke, Air Track, Heat, and Flame Indicators; then answer the following five standard questions?
What additional information would you like to have? How could you obtain it?
What stage(s) of development is the fire likely to be in (incipient, growth, fully developed, or decay)?
What burning regime is the fire in (fuel controlled or ventilation controlled)?
What conditions would you expect to find inside this building?
How would you expect the fire to develop over the next two to three minutes
watch the next 20 seconds (from 0:25 to 0:40). How do the B-SAHF indicators change? Why might this be the case?
Watch 20 seconds the video showing conditions at the doorway on Side B starting 50 seconds (0:50 to 1:10). Are the indicators visible from this vantage point similar to those on Side A? Why or why not?
Now watch the video up until the arrival of the first engine company (at 1:25). How do you think fire conditions are changing inside the garage? Is the heat release increasing, decreasing, or remaining relatively constant? Why?
Continue watching the video until 3 minutes 45 seconds (3:20). How do the smoke and air track indicators change (both before and after the overhead door on Side A was opened)?
At approximately 4:18 flames become visible from a window on Side C? Is this surprising? Why or why not?
How is a fire in a garage different than a fire in the living areas of a dwelling? How might these differences influence fire behavior and impact on firefighter safety?
Reading the Fire
See the following posts for more information on reading the fire:
At breakfast this morning, I met Commander Oscar Ruiz member at Lima Station 4 and former Chief of Station 100. In 1997, Oscar was injured as the result of a backdraft while operating in the basket of an aerial platform at a commercial fire in the Victoria district of Lima. My next post will examine this incident and important lessons learned.
This post continues examination of the incident that took the life of Firefighter Brian Carey and seriously injured Firefighter Kara Kopas on the evening of March 30, 2010 while they were operating a hoseline in support of primary search in a small, one-story, wood frame dwelling with an attached garage at 17622 Lincoln Avenue in Homewood, Illinois.
This post focuses on firefighting operations, key fire behavior indicators, and firefighter rescue operations implemented after rapid fire progression that trapped Firefighters Carey and Kopas.
Firefighting Operations
After making initial assignments, the Incident Commander performed reconnaissance along Side Bravo to assess fire conditions. Fire conditions at around the time the Incident Commander performed this reconnaissance are illustrated in Figure 7. After completing recon of Side B, the Incident Commander returned to a fixed command position in the cab of E-534 (in order to monitor multiple radio frequencies).
Figure 7. Conditions Viewed from Side C during the Incident Commander’s Recon
Note: John Ratko Photo from NIOSH Death in theLine of Duty Report F2010-10.
Engine 1340 (E-1340) arrived and reported to Command for assignment. The five member crew of this company was split to assist T-1220 with vertical ventilation, horizontally ventilate through windows on Sides B and D, and to protect Exposures D and D2.
One member of E-1340 assisted T-1220 and the remaining members vented the kitchen windows on SidesD and B, while the E-1340 Officer stretched a 1-3/4” (45 mm) hoseline from E-534 to protect exposures on Side D. However, this line was not charged until signficantly later in the incident (see Figure 14). Figure 8 (a-c) illustrates changing conditions as horizontal ventilation is completed on Sides B and D.
Figure 8. Sequence of Changing Conditions Viewed from the A/B Corner
At 2105 Command reported that crews were conducting primary search and were beginning to vent.
Note the B-SAHF indicators visible from the A/B Corner in Figure 8a: Dark gray smoke from the door on Side A with the neutral plane at approximately 18” (0.25 m) above the floor. Velocity and turbulence are moderate and a bidirectional air track is evident at the doorway.
As the 2-1/2” (64 mm) handline reached the kitchen, flames were beginning to breach the openings in the Side C wall of the house and thick black smoke had banked down almost to floor level. As noted in Figure 3 (and subsequent floor plan illustrations), there were doors and windows between the house and addition in the Utility Room and Bedroom 2 . The Firefighter from E-534 had a problem with his protective hood and handed the nozzle off to Firefighter Carey and instructed him to open and close the bail of the nozzle quickly. After doing so, the Firefighter from E-534 retreated along the hoseline to the door on Side A to correct this problem (heis visible in the doorway in Figure 8c).
As E-1340 vents windows on Sides B (see Figure 8b) and D, the level of the neutral plane at the doorway on Side A lifts, but velocity and turbulence of smoke discharge increases. Work continues on establishing a vertical vent, but is hampered by smoke discharge from the door on Side A.
After horizontal ventilation of Sides B and D, velocity and turbulence of smoke discharge continues to increase and level of the upper layer drops to the floor as evidenced by the neutral plane at the door on Side A (see Figures 8b and 8c)
The photo in Figure 8c was taken just prior to the rapid fire progression that trapped Firefighters Carey & Kopas. The Firefighter from E-534 is visible in the doorway correcting a malfunction with his protective hood.
As T-1220B reached the hallway leading to the bedrroms, they felt a significant increase in temperature and visibility worsened. After searching Bedroom 2 and entering Bedroom 1 temperature contiued to increase and T-1220B observed flames rolling through the upper layer in the hallway leading from Bedroom 2 and the Bathroom. Note: NIOSH Death in the Line of Duty Report 2010-10 does not specify if T-1220B searched Bedroom 2, but this would be consistent with a left hand search pattern. They immedidately retreated to the Living Room looking for the hoseline leading to the door on Side A. As they did so, they yelled to the crew on the 2-1/2” (64 mm) handline to get out.
Extreme Fire Behavior
Firefighter Kopas felt a rapid increase in temperature as the upper layer ignited throughout the living room and the fire in this compartment transitioned to a fully developed stage. She yelled to Firefighter Carey, but received no response as she turned to follow the 2-1/2” (64 mm) hoseline back to the door on Side A. She made it to within approximately 4’ (1.2 m) of the front door when her protective clothing began to stick to melted carpet and she became stuck. T-1220B saw that she was trapped, reentered and pulled her out.
Figure 12. Position of the Crews as the Extreme Fire Behavior Phenomena Occurred
Note: It is unknown if T-1220B searched Bedroom 2 before entering Bedroom 1. However, this would be consistent with a left hand search pattern.
Figure 13. Conditions Viewed from the Alpha/Bravo Corner as the Extreme Fire Behavior Occured
Note: Warren Skalski Photo from NIOSH Death in theLine of Duty Report F2010-10.
Figure 14. Conditions Viewed from the Alpha/Delta Corner as the Extreme Fire Behavior Occured
Note: Warren Skalski Photo from NIOSH Death in theLine of Duty Report F2010-10.
Following the transition to fully developed fire conditions in the living room, the Incident Commander ordered T-1220 off the roof. As illustrated in Figure 14, the exposure protection line stretched by E-1340 was not charged until after Firefighter Carey was removed from the building.
Figure 15. Position of Search and Fire Control Crews after Rapid Fire Progress
Firefighter Rescue Operations
The Incident Commander and Firefighter from E-534 (who had retreated to the door due to a problem with his protective hood), pulled a second 1-3/4” (45 mm) line from E-534. T-1220B re-entered the house with this hoseline to locate Firefighter Carey.
While advancing into the living room, T-1220B discovered that E-534’s 2-1/2” (64 mm) handline. They controlled the fire in the living room using a direct attack on burning contents and advanced to the kitchen where they discovered Firefighter Carey entangled in the 2-1/2” (64 mm) handline. Firefighter Carey’s helmet and breathing apparatus facepiece were not in place.
T-1220B removed Firefighter Carey from the building where he received medical care from T-1145. A short time later, Firefighter Carey became apenic and pulseless. After the arrival of Ambulance 2101 (A-2101), Firefighter Carey was transported to Advocate South Suburban Hospital in Hazel Crest, IL where he was declared dead at 10:03 pm.
According to the autopsy report, Firefighter Carey had a carboxyhemoglobin (COHb) of 30% died from carbon monoxide poisoning. The NIOSH Death in the Line of Duty Report (2010) did not indicate if the medical examiner tested for the presence of hydrogen cyanide (HCN) or if thermal injuries were a contributing factor to Firefighter Carey’s death.
Timeline
Review the Homewood, Illinois Timeline (PDF format) to gain perspective of sequence and the relationship between tactical operations and fire behavior.
Contributing Factors
Firefighter injuries often result from a number of causal and contributing factors. NIOSH Report F2010-10 identified the following contributing factors in this incident that led to the death of Firefighter Brian Carey and serious injuries to Firefighter Kara Kopas.
Well involved fire with trapped civilian upon arrival.
Incomplete 360o situational size-up
Inadequate risk-versus-gain analysis
Ineffective fire control tactics
Failure to recognize, understand, and react to deteriorating conditions
Uncoordinated ventilation and its effect on fire behavior
Removal of self-contained breathing apparatus (SCBA) facepiece
Inadequate command, control, and accountability
Insufficient staffing
Questions
The following questions focus on fire behavior, influence of tactical operations, and related factors involved in this incident.
What type of extreme fire behavior phenomena occurred in this incident? Why do you think that this is the case (justify your answer)?
How did the conditions necessary for this extreme fire behavior event develop (address both the fuel and ventilation sides of the equation)?
What fire behavior indicators were present in the eight minutes between arrival of the first units and occurrence of the extreme fire behavior phenomena (organize your answer using Building, Smoke, Air Track, Heat, and Flame (B-SAHF) categories)? In particular, what changes in fire behavior indicators would have provided warning of impending rapid fire progression?
Did any of these indicators point to the potential for extreme fire behavior? If so, how? If not, how could the firefighters and officers operating at this incident have anticipated this potential?
What was the initiating event(s) that lead to the occurrence of the extreme fire behavior that killed Firefighter Carey and injured Firefighter Kopas?
How did building design and construction impact on fire behavior and tactical operations during this incident?
What action could have been taken to reduce the potential for extreme fire behavior and maintain tenable conditions during primary search operations?
How would you change, expand, or refine the list of contributing factors identified by the NIOSH investigators?
A number of years ago, several nozzle manufacturers developed a break apart combination nozzle (shutoff separate from the tip) with an integrated solid stream tip. This design allowed the user to adjust the pattern using the combination tip, or if desired, remove the combination tip and use the nozzle to develop a solid stream. Good idea or not? On the surface this sounds like it might be a reasonable idea. The combination tip allows adjustment of the pattern while the internal solid stream may provide improved performance in penetration to reach burning fuel surfaces. In addition, if the combination tip became clogged with debris it is also possible to remove the tip and still have the capability to develop a usable fire stream.
Used on various size handlines, internal solid stream tips are generally available in sizes ranging from 7/8” to 1-1/4”. What effect does an integrated solid stream tip have on nozzle performance when a combination tip is used? Manufacturers such as Elkhart Brass and Task Force Tips warn that the integrated smooth bore tip may restrict the flow of single flow, variable flow, or automatic combination tips.
CWIFR Nozzle Tests
Tests conducted by Firefighter Jim Huff of Central Whidbey Island Fire & Rescue (CWIFR) demonstrate the potential friction loss impact of integrated solid stream tips. CWIFR conducted flow tests using an mid-range Elkhart Phantom tip, a 1-1/2” (38 mm) ball valve, and a 1-1/2” (38 mm) ball valve with an integrated 15/16” (23.8 mm) tip. Line gages were inserted at the base of the nozzle and between the shutoff and the tip. Nozzle inlet pressure was adjusted to maintain the designed nozzle pressure of 100 psi (690 kPa) at the tip and pressure measurements were made at each of the nozzles flow settings of 30, 95, 125, 150, and 200 gpm (114, 360, 473, 658, and 757 lpm).
As illustrated in Figure 1, the ball valve without the integrated tip had limited impact on tip pressure.
Figure 1. Full Flow Ball Valve
However, the results obtained when using a 1-1/2” (38 mm) ball valve with an integrated 15/16” (23.8 mm)solid stream tip were dramatically different. As illustrated in Figure 2, a considerably higher inlet pressure was required to provide the designed operating pressure of 100 psi (690 kPa) at the tip.
Figure 2. Ball Valve with a Solid Stream Tip
When equipped with an integrated solid stream tip, the friction loss in the nozzle shutoff is significantly impacted by tip size (the smaller the tip, the greater the friction loss at a given flow rate).
This is my nozzle, there are many like it but this one is mine. My nozzle is my best friend. It is my life. I must master it as I master my life. Without me it is useless, without my nozzle I am useless.
I will use my nozzle effectively and efficiently to put water where it is needed. I will learn its weaknesses, its strengths, its parts, and its care. I will guard it against damage, keep it clean and ready. This I swear.
It is essential that firefighters, apparatus operators, and fire officers have an in-depth knowledge of their tools. A handline nozzle is your primary firefighting weapon in offensive firefighting operations, develop your nozzle knowledge and master this important tool.
Developing and maintaining proficiency in reading the Fire using the B-SAHF (Building, Smoke, Air Track, Heat, and Flame) organizing scheme for fire behavior indicators, requires practice. This post provides an opportunity to exercise your skills using a video segment shot during a commercial fire.
Commercial Fire
This post examines fire development during a fire in an agricultural facility in Spain. First arriving firefighters observed a small amount of light gray smoke issuing from roof ventilators and doorways with low velocity.
Watch the first 50 seconds (0:50) of the video. First, describe what you observe in terms of the Building, Smoke, Air Track, Heat, and Flame Indicators; then answer the following five standard questions?
What additional information would you like to have? How could you obtain it?
What stage(s) of development is the fire likely to be in (incipient, growth, fully developed, or decay)?
What burning regime is the fire in (fuel controlled or ventilation controlled)?
What conditions would you expect to find inside this building?
How would you expect the fire to develop over the next two to three minutes
Now watch the next 20 seconds (1:10) of the video clip and answer the following questions:
Did fire conditions progress as you anticipated?
What changes in the B-SAHF indicators did you observe?
How do you think that the stage(s) of fire development and burning regime will change over the next few minutes?
What conditions would you expect to find inside this building now?
How would you expect the fire to develop over the next two to three minutes
Watch the remainder of the video. If you were the Incident Commander and had crews working inside the building, what information would you communicate to them as conditions change?
Reading the Fire
See the following posts for more information on reading the fire:
It has been a number of months since the last Reading the Fire post. It is essential to continue the process of deliberate practice in order to continue to improve and refine skill in Reading the Fire.
As we start the New Year it is a good time to reaffirm our commitment to mastering our craft. Developing and maintaining proficiency in reading the Fire using the B-SAHF (Building, Smoke, Air Track, Heat, and Flame) organizing scheme for fire behavior indicators, requires practice. This post provides an opportunity to exercise your skills using a video segment shot during a residential fire.
Residential Fire
In mid-January 2010, the Gary, Indiana Fire Department was dispatched to a residential fire on Massachusetts Street at East 24th Avenue, on arrival Battalion 4 advised of a working fire in a 2 story dwelling. While the first arriving engine was laying a supply line from a nearby hydrant, the first in truck forced entry.
Watch the first 35 seconds (0:35) of the video. This segment was shot from Side A. First, describe what you observe in terms of the Building, Smoke, Air Track, Heat, and Flame Indicators; then answer the following five standard questions?
What additional information would you like to have? How could you obtain it?
What stage(s) of development is the fire likely to be in (incipient, growth, fully developed, or decay)?
What burning regime is the fire in (fuel controlled or ventilation controlled)?
What conditions would you expect to find inside this building? If presented with persons reported (as the first arriving companies were) how would you assess potential for victim survival?
How would you expect the fire to develop over the next two to three minutes
Now watch the remainder of the video clip and answer the following questions:
Did fire conditions progress as you anticipated?
A voice heard in the video states that this was a backdraft. Do you agree? Why or why not?
It is likely that the first in truck company in this incident made entry to search for occupants and to locate the fire. Regardless of your perspective on search with or without a hoseline, this video clip provides lessons.
It is essential to read the fire, recognize the stage(s) of fire development and burning regime(s) in the involved compartments.
In addition to reading current conditions, anticipate likely fire development and potential for extreme fire behavior.
Making entry (and leaving the door fully open) creates a ventilation opening (inlet, exhaust, or both). Recognize the potential influence of changes to the ventilation profile on fire behavior.
To borrow a phrase from a number of National Institute for Occupational Safety and Health Death in the Line of Duty reports; Ventilation and fire attack must be closely coordinated. One key element in this coordination is that charged lines must be in place before completion of ventilation openings. This is critical when dealing with a ventilation controlled fire.
The previous post in this series presented a video clip of an incident on the afternoon of February 18, 2010 that injured four Chicago firefighters during operations at a residential fire at 4855 S. Paulina Street.
First arriving companies discovered a fire in the basement of a 1-1/2 story, wood frame, single family dwelling and initiated fire attack and horizontal ventilation of the floors above the fire. Based on news accounts, the company assigned to fire attack was in the stairwell and another firefighter was performing horizontal ventilation of the floors above the fire on Side C when a backdraft or smoke explosion occurred. Two firefighters on the interior, on at the doorway and the firefighter on the ladder on Side C were injured and were transported to local hospitals for burns and possible airway injuries.
In analyzing the video clip shot from inside a nearby building, we have several advantages over the firefighters involved in this incident.
Time: We are not under pressure to make a decision or take action.
Reduced Cognitive Workload: Unlike the firefighters who needed to not only read the fire, but also to attend to their assigned tactics and tasks, our only focus is analysis of the fire behavior indicators to determine what (if any) clues to the potential for extreme fire behavior may have been present.
Repetition: Real life does not have time outs or instant replay. However, our analysis of the video can take advantage of our ability to pause, and replay key segments, or the entire clip as necessary.
Perspective: Since the field of view in the video clip is limited by the window and the fidelity of the recording is less than that seen in real life, it presents a considerably different field of view than that of the firefighters observed in operation and does not allow observation of fire behavior indicators and tactical operations on Sides A, B, and D.
Initial Size-Up
What B-SAHF indicators could be observed on Side C up to the point where firefighters began to force entry and ventilate the basement (approximately 02:05)?
Figure 1. Conditions at 01:57 Minutes Elapsed Time in the Video Clip
Building: The structure is a 1-1/2 story, wood frame, dwelling with a daylight basement. The apparent age of the structure makes balloon frame construction likely, and the half story on the second floor is likely to have knee walls, resulting in significant void spaces on either side and a smaller void space above the ceiling on Floor 2. One window to the left of the door on Side C appears to be covered with plywood (or similar material). Given the location of the door (and door on Side A illustrated in the previous post in this series), it is likely that the stairway to the basement is just inside the door in Side C and a stairway to Floor 2 is just inside the door on Side A.
Smoke: A moderate volume of dark gray smoke is visible from the Basement windows and windows and door on Floor 1 as well as a larger volume from above the roofline on Side B. While dark, smoke on Side C does not appear to be thick (optically dense), possibly due to limited volume and concentration while smoke above the roofline on Side B appears to be thicker. However smoke on Side C thickens as time progresses, particularly in the area of the door on Floor 1. The buoyancy of smoke is somewhat variable with low buoyancy on Side C and greater buoyancy on Side B. However, smoke from the area of the door on Floor 1 Side C intermittently has increased buoyancy.
Air Track: Smoke on Side C appears to have a faintly pulsing air track with low velocity which is masked to some extent by the effects of the wind (swirling smoke due to changes in low level wind conditions). Smoke rising above the roofline on Side B appears to be moving with slightly greater velocity (likely due to buoyancy).
Heat: The only significant heat indicators are limited velocity of smoke discharge and variations in buoyancy of smoke visible from Sides B and C. Low velocity smoke discharge and low buoyancy of the smoke on Side C points to relatively low temperatures inside the building. The greater buoyancy and velocity of smoke observed above the roofline on Side B indicates a higher temperature in the area from where this smoke is discharging (likely a basement window on Side B).
Flame: No flames are visible.
Initial Fire Behavior Prediction
Based on assessment of conditions to this point, what stage(s) of development and burning regime(s) is the fire likely to be in?
Dark smoke with a pulsing air track points to a ventilation controlled, decay stage fire.
What conditions would you expect to find inside the building?
Floors 1 and 2 are likely to be fully smoke logged (ceiling to floor) with fairly low temperature. The basement is likely to have a higher temperature, but is also likely to be fully smoke logged with limited flaming combustion.
How would you expect the fire to develop over the next few minutes?
As ventilation is increased (tactical ventilation and entry for fire control), the fire in the basement will likely remain ventilation controlled, but will return to the growth stage as the heat release rate increases. Smoke thickness and level (to floor level) along with a pulsing air track points to potential for some type of ventilation induced extreme fire behavior such as ventilation induced flashover (most likely) or backdraft (less likely). Another possibility, would be a smoke explosion; ignition of premixed gas phase fuel (smoke) and air that is within its flammable range (less likely than some type of ventilation induced extreme fire behavior)
Ongoing Assessment
What indicators could be observed while the firefighter was forcing entry and ventilating the daylight basement on Side C (02:05-02:49)?
There are few changes to the fire behavior indicators during this segment of the video. Building, Heat, and Flame indicators are essentially unchanged. Smoke above the roofline appears to lighten (at least briefly) and smoke on Side C continues to show limited buoyancy with a slightly pulsing air track at the first floor doorway.
What B-SAHF indicators can be observed at the door on Side C prior to forced entry (02:49-03:13)?
Figure 2. Conditions at 03:06 Minutes Elapsed Time in the Video Clip
Figure 3. Conditions at 03:08 Minutes Elapsed Time in the Video Clip
Building, Smoke, Heat and Flame indicators remain the same, but several more pulsations (03:05-03:13) providing a continuing, and more significant indication of ventilation controlled, decay stage fire conditions.
What indicators can be observed at the door while the firefighter attempts to remove the covering over the window adjacent to the door on Floor 1 (03:13-13:44)?
No significant change in Building, Heat, or Flame Indicators. However, smoke from the doorway has darkened considerably and there is a pronounced pulsation as the firefighter on the ladder climbs to Floor 2 (03:26). It is important to note that some of the smoke movement observed in the video clip is fire induced, but that exterior movement is also significantly influenced by wind.
What B-SHAF indicators do you observe at the window on Floor 2 prior to breaking the glass (03:44)?
Figure 4. Conditions at 03:43 Minutes Elapsed Time in the Video Clip
The window on Floor 2 is intact and appears to be tight as there is no smoke visible on the exterior. It is difficult to tell due to the angle from which the video was shot (and reflection from daylight), but it would be likely that the firefighter on the ladder could observe condensed pyrolizate on the window and smoke logging on Floor 2. It is interesting to note limited smoke discharge from the top of the door and window on Floor 1 in the brief period immediately prior to breaking the window on Floor 2.
What indicators are observed at the window on Floor 2 immediately after breaking the glass (03:44-03:55)?
Figure 5. Conditions at 03:52 Minutes Elapsed Time in the Video Clip
No significant changes in Building, Heat, or Flame indicators. Dark gray smoke with no buoyancy issues from the window on Floor 2 with low to moderate velocity immediately after the window is broken.
What B-SAHF indicators were present after the ventilation of the window on Floor 2 Side C was completed and 04:08 in the video clip (03:44-04:08)?
Buoyancy and velocity both increase and a slight pulsing air track develops within approximately 10 seconds. In addition, the air track at the door on Floor 1 shifts from predominantly outward with slight pulsations to predominantly inward, but with continued pulsation (possibly due to the limited size of the window opening on Floor 2, Side C.
Anticipating Potential Fire Behavior
Unlike the firefighters in Chicago who were operating at this incident, we can hit the pause button and consider the indicators observed to this point. Think about what fire behavior indicators are present (and also consider those that are not!).
Initial observations indicated a ventilation controlled decay stage fire and predicted fire behavior is an increase in heat release rate with potential for some type of extreme fire behavior. Possibilities include ventilation induced flashover (most likely) or backdraft (less likely), or smoke explosion (less likely than some type of ventilation induced extreme fire behavior).
Take a minute to review the indicators of ventilation controlled, decay stage fires as illustrated in Table 1.
Table 1. Key Fire Behavior Indicators-Ventilation Controlled, Decay Stage Fires
Which of these indicators were present on Side C of 4855 S. Paulina Street?
Building: The building appeared to be unremarkable, a typical single family dwelling. However, most residential structures have more than enough of a fuel load to develop the conditions necessary for a variety of extreme fire behavior phenomena.
Smoke: The dark smoke with increasing thickness (optical density) is a reasonably good indicator of ventilation controlled conditions (particularly when combined with air track indicators). Lack of buoyancy indicated fairly low temperature smoke, which could be an indicator of incipient or decay stage conditions or simply distance from the origin of the fire. However, combined with smoke color, thickness, and air track indicators, this lack of buoyancy at all levels on Side C is likely an indicator of dropping temperature under decay stage conditions. This conclusion is reinforced by the increase in buoyancy after ventilation of the window on Floor 2 (increased ventilation precipitated increased heat release rate and increasing temperature).
Air Track: Pulsing air track, while at times quite subtle and masked by swirling smoke as a result of wind, is one of the strongest indications of ventilation controlled decay stage conditions. While often associated with backdraft, this indicator may also be present prior to development of a sufficient concentration of gas phase fuel (smoke) to result in a backdraft.
Heat: Velocity of smoke discharge (air track) and buoyancy (smoke) are the only two heat indicators visible in this video clip. As discussed in conjunction with smoke indicators, low velocity and initial lack of buoyancy which increases after ventilation is indicative of ventilation controlled, decay stage conditions.
Flame: Lack of visible flame is often associated with ventilation controlled decay and backdraft conditions. However, there are a number of incidents in which flames were visible prior to occurrence of a backdraft (in another compartment within the structure). Lack of flames must be considered in conjunction with the rest of the fire behavior indicators. In this incident, lack of visible flames may be related to the stage of fire development, but more likely is a result of the location of the fire, as there is no indication that flames were present on Side C prior to the start of the video clip.
What Happened?
Firefighters had entered the building for fire attack while as illustrated in the video clip, others were ventilating windows on Side C. It is difficult to determine from the video if a window or door at the basement level on Side C was opened, but efforts were made to do so. A window on Floor 2 had been opened and firefighters were in the process of removing the covering (plywood) from a window immediately adjacent to the door on Floor 1. At 04:12, an explosion occurred, injuring two firefighters on the interior as well as the two firefighters engaged in ventilation operations on Side C.
Starting at approximately 03:59, velocity of smoke discharge from the window on Floor 2 Side C increases dramatically. At 04:08 discharge of smoke begins to form a spherical pattern as discharged from the window. This pattern becomes more pronounced as the sphere of smoke is pushed away from the window by increasing velocity of smoke discharge at 04:12, immediately prior to the explosion. Velocity of smoke discharge at the door increases between 03:59 and -4:12 as well, but as the opening is larger, this change is less noticeable. As pressure increases rapidly during the explosion a whooshing sound can be heard. After the explosion, there was no noticeable increase in fire growth.
Figure 6. Conditions at 04:08 Minutes Elapsed Time in the Video Clip
Figure 7. Conditions at 04:09 Minutes Elapsed Time in the Video Clip
Figure 8. Conditions at 04:10 Minutes Elapsed Time in the Video Clip
Figure 9. Conditions at 04:11 Minutes Elapsed Time in the Video Clip
Figure 10. Conditions at 04:12 Minutes Elapsed Time in the Video Clip
Figure 11. Conditions at 04:13 Minutes Elapsed Time in the Video Clip
Based on observation of fire behavior indicators visible in the video clip, we know that a transient extreme fire behavior event occurred while a crew was advancing a hoseline on the interior and ventilation operations were being conducted on Side C. What we dont know is what firefighting operations were occurring on the other sides of the building or in the interior. In addition, we do not have substantive information from the fire investigation that occurred after the fire was extinguished.
The Ontology of Extreme Fire Behavior presented in an earlier post classifies these types of phenomena on the basis of outcome and conditions. As a transient and explosive event, this was likely a backdraft or smoke explosion. In that this occurred following entry and during ongoing ventilation operations, I am inclined to suspect that it was a backdraft.
Indicators visible on Side C provided a subtle warning of potential for some type of ventilation induced extreme fire behavior, but were likely not substantially different from conditions observed at many fires where extreme fire behavior did not occur.
As the title of the wildland firefighting course S133 states; Look Up, Look Down, Look Around! Anticipation of fire development and extreme fire behavior requires not only recognition of key indicators, but that these indicators be viewed from a holistic perspective. Firefighters and/or officers performing a single task or tactical assignment may only see part of the picture. It is essential that key indicators be communicated to allow a more complete picture of what is occurring and what may occur as incident operations progress.
Updated March 7, 2010 with Longer Video Clip of this Incident
On the afternoon of February 18, 2010, firefighters in Chicago responded to a residential fire at 4855 S. Paulina Street. First arriving companies discovered a fire in the basement of a 1-1/2 story, wood frame, single family dwelling and initiated fire attack and horizontal ventilation of the floors above the fire.
Based on news accounts, the company assigned to fire attack was in the stairwell and another firefighter was performing horizontal ventilation of the floors above the fire on Side C when a backdraft or smoke explosion occurred. Three firefighters on the interior and the firefighter on the ladder on Side C were injured and were transported to local hospitals for burns and possible airway injuries.
Figure 1. Consider Key Fire Behavior Indicators
B-SAHF Indicators
Recognizing subtle fire behavior indicators during incident operations can be difficult and important indicators are often only visible from one location (other than where you are). What Building, Smoke, Heat, and Flame (B-SAHF) indicators would you anticipate seeing if potential backdraft conditions exist (or may develop as the incident progresses)? How would this differ from the indicators that conditions may present risk of a smoke explosion?
For more information on key fire behavior indicators related to ventilation controlled burning regime, decay stage fires, backdraft, and smoke explosion, see the following posts:
A video of the incident at 4855 S. Paulina Street was recently posted on YouTube (a shorter version is posted on Firevideo.net). It appears that the video may have been shot through a window by an occupant of the D2 exposure. The title of this video is Chicago Smoke Explosion. After watching the video and answering the questions posed in this post, do you think that this was a backdraft or smoke explosion? Why?
One of the great assets of using video as a learning tool is the ability to stop the action and go back to review key information. Watch the video and stop the action as necessary to answer the following questions
Pause at 02:05. What B-SAHF indicators could be observed on Side C up to this point in the video clip?
Pause at 02:49. What indicators could be observed while the firefighter was forcing entry and ventilating the daylight basement on Side C?
Pause at 03:13. What B-SAHF indicators can be observed at the door on Side C prior to forced entry?
Pause at 03:35. What indicators can be observed at the door after forcing the outer door (prior to ventilation of the window on Floor 2)?
Pause at 03:44. What B-SHAF indicators do you observe at the window on Floor 2 prior to breaking the glass?
Pause at 03:55. What indicators are observed at the window on Floor 2 immediately after breaking the glass?
Pause at 04:08. What B-SAHF indicators were present after the ventilation of the window on Floor 2 Side C was completed and 04:08 in the video clip?
After answering the questions, watch the complete clip. Do you think that this was a backdraft or smoke explosion? If you thought that this was a backdraft: Did you see potential indicators? If so what were they? If not, why do you think that this was the case? If you think that this was a smoke explosion, what indications lead you to this conclusion? What indicators were present?
You may want to watch this video clip several times and give some thought to what factors were influencing the B-SAHF indicators (particularly smoke, air track, and heat). Were these indicators consistent with your perception of backdraft indicators? Is so, how? If not, what was different? What indicators may have been visible from other vantage points. Remember that the video provides a view from a single perspective (and one that is considerably different than the crews working at this incident).
The next post in this series will take a closer look at the video and key fire behavior indicators.
