SPE UMR 6134 CNRS, University of Corsica, Campus Grimaldi BP 52, 20250 Corte, France
Copyright © 2011 Paul-Antoine Santoni et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
This work presents the extension of a physical model for the spreading of surface fire at landscape scale. In previous work, the model was validated at laboratory scale for fire spreading across litters. The model was then modified to consider the structure of actual vegetation and was included in the wildland fire calculation system Forefire that allows converting the two-dimensional model of fire spread to three dimensions, taking into account spatial information. Two wildland fire behavior case studies were elaborated and used as a basis to test the simulator. Both fires were reconstructed, paying attention to the vegetation mapping, fire history, and meteorological data. The local calibration of the simulator required the development of appropriate fuel models for shrubland vegetation (maquis) for use with the model of fire spread. This study showed the capabilities of the simulator during the typical drought season characterizing the Mediterranean climate when most wildfires occur.
The ability of the forest fire community in modelling and simulating forest fire spread [1–4], as well as developing management approaches and techniques , has increased significantly in recent years. Modelling has become an essential tool in forest fire research and becomes a crucial instrument in the studies of wildland-urban interface fires , fire mitigation, and risk mapping . Wildfires are driven by complex physical and chemical processes, operating on vastly different scales ranging from micrometers to kilometers. Their interactions depend on coupling between nonlinear phenomena such as turbulence in the lower part of the atmospheric boundary layer, topography, vegetation, and fire itself (chemical reactions, radiation heat transfer, and degradation of the vegetation). Different reviews of fire spread models have been conducted these last ten years [6, 7]. Depending on the authors, wildland fire mathematical models may be classified according to the nature of the equations (physical, quasiphysical, quasiempirical, and empirical) or according to the physical system modeled (surface fire models, crown fire models, spotting models, and ground fire models). With regard to the first classification, the simplest models are the statistical ones, which make no attempt to involve physical mechanisms . Empirical models  are based upon the conservation of energy, but they do not distinguish the mode of heat transfer. Finally, physical models differentiate the various kinds of heat transfer in order to predict fire behaviour . Among them, multiphase modeling  and coupled fire-fuel-atmosphere models [1, 11] represent the most complete approach developed so far. Whatever the classification, there is a general agreement on the fact that simple models have to be used if one wants to provide real-time operational tools. Conversely, multidimensional numerical fluid-dynamical wildfire simulation models must be used to study the behavior of wildfire and wildland-urban interface fires. However, these last models require computational resources that preclude real-time forecasts . The computational cost of physics-based wildland fire modeling limits the application of the approach to modeling wildfire behaviour within a certain scale range. On another hand, quasiempirical and empirical model may be very efficient for fuel and environmental conditions comparable to those of test-fires, but the absence of a real physical description makes them inapplicable to other situations. The dilemma is whether one wants to simulate wildfire phenomenon accurately or quickly.
The aim of the present paper is to extend at landscape scale a physical model of surface fire . Up to now, the model has been tested only at laboratory scale against experiments for which fuel beds of pine needles or straw were used . Although pine litter presents a clear fire hazard in pine forests by providing a continuous fuel matrix across the forest floor, fire hazard also corresponds clearly to grassfires, fires in shrubland and forest fires. Our model of fire spread was thus modified to take into account the structure of the actual vegetation. Particular attention was paid to intermixed live and dead vegetation found in the Mediterranean maquis. Fire behavior fuel models were developed for some Mediterranean vegetation types in order to match the requirements of the modified model of surface fire. The fire model was included in the wildland fire calculation system Forefire . Forefire allows conversion of the two-dimensional model () to three dimensions () and then simulating the propagation of the fire perimeter across a modeled landscape, taking into account spatial information. Two wildfire case studies have been reconstructed and used to test the simulation model. Wildland fires are very difficult, if not impossible, to study with full-scale repeatable experiments in the field  due to their expense, safety implications, and variations in atmosphere, terrain, and fuel conditions. However, although basic research on combustion is essential to a full understanding of fire behavior, such research would not be very useful without actual field experience gained and case study documentation. Wildfire case studies are invaluable in providing fire behavior data for developing and evaluating fire behavior models . The contribution of the present work is the development of a wildfire calculation system based on a physical model of fire spread that satisfies two contradictory properties: to be as complete as possible with regard to the equations that govern fires and to be as simple as possible to predict fire behavior faster than real time. The model distinguishes the mode of heat transfer and avoids the complexity of the chemical aspect related to combustion. It is, thus, able to provide information on physical quantities like radiant heat flux . Conversely, most commonly used operational models for wildland fire spread rely on empirically derived relations to predict the spread rate of a wildland fire across landscapes. In the United States, FARSITE  is based on the quasiempirical spread model of Rothermel . In Australia, SiroFire  uses McArthur’s fire spread models for grass  and forest  as well as the recommended replacement grassland model . The Canadian Wildland Fire Growth Model, Prometheus , is based on the Canadian Fire Behaviour Prediction System  and uses the wavelet propagation algorithms of Richards . The approach presented in the current paper is not a coupled atmosphere-wildland fire model. We use realistic precalculated wind field data as input. The impact of the fire on the atmosphere and the subsequent feedback of these fire-induced winds on fire behavior are not simulated.
2. Fire Model and Fire Simulator Overviews
2.1. Fire Model
The aim is to provide a model of surface fire that will form the core of a simulation tool for fire fighters. The model is derived from a simplified modeling of the transport phenomena governing the fire [3, 12]. It is physical, because in addition to rate of spread, it provides also the main global physical quantity related to the fire front such as radiant heat flux. Its computational time must be low to be usable under real time conditions for the simulation of actual wildland fires. Its accuracy must be reasonably good. The main calculation steps leading to the model equations are provided in appendix. The appendix describes the first version of the model elaborated at laboratory scale for dead fuel. The interested reader is referred to [3, 12] for more details on this model. In this section, we outline these equations, and we propose some modification to simulate actual vegetation. The main equations are for the flame tilt angle and for the rate of spread . and are, respectively, given by In (1), represents the slope angle, is the angle between the unit vector, normal to the fire front and the unit ground slope vector, and is the angle between the unit vector normal to the fire front and the wind velocity vector, . is the value of the wind velocity. In (2), and represent, respectively, the contributions to rate of spread, of the radiation due to embers, and radiation due to the flame when it is tilted under wind and/or slope condition (Figure 1).
Figure 1: Flame profile along the normal direction to the fire front.
In (3), is the depth of the vegetation, is the fuel load, is the Stefan-Boltzman constant ( W/(m2K4)), is the temperature in the burning fuel, is the specific heat of the fuel, , where is the temperature of ignition and is the ambient temperature, is the fuel moisture content on dry basis, and is the latent heat of vaporization of water ( kJ/kg). In (1) and (4), the terms , , and are given bywhere stands for the upward velocity of the combustion gases under no slope. It is given by (5a), (6a), and (6b) in which is the surface to volume ratio of the fuel, is the packing ratio of the fuel, is stoichiometric mass-based air/fuel ratio for the complete combustion of pyrolisis gases in air (), is the empirical constant provided by Anderson  for the residence time of fire, is the density of the fuel and is the density of ambient air. In (6c), represents the radiant fraction of the rate of heat release within the flame. The model assumes that the radiant heat transfer fraction decreases when the volume to surface ratio of the flame increases and is a model parameter used to establish this relationship . In (6d), is the net heat of combustion of the combustible gases and is the specific heat content of air at 1273 K ( J·kg−1·K−1). The values of the model parameters are s·m−1, and m·s−1. The fuel parameters are given in the section devoted to the presentation of the fire behaviour fuel model.
As mentioned in Section 1, we recall that our aim is to extend at landscape scale this model of surface fire. Hence, the simple structure of the model was kept, considering that shrubland fires are surface fires. Shrubland include both dead and live vegetations that must be considered in the thermal balance. Two hypotheses are thus formulated. We first assume that thin dead fuels (1-h) are mainly responsible of the fire spread considering that live fuels and coarse dead fuels (greater than 10-h) are partly desiccated within the flame and not only ahead of the fire front. We assume also that ahead of the fire front, the heat flux impinges both dead and live fuels in proportion to their leaf area index. With these hypotheses, (2), (6c), and (6d) become with In these relations, the subscripts and are, respectively, for 1-h dead and thin live fuels, while , , , and remain as defined in this section.
2.2. Fire Simulator
The model of fire spread is bidimensional, since it provides the flame height (not detailed here but given in ) and the forward rate of spread. It is, however, necessary to develop a method of converting the forward spread model into a two-dimensional one that could spread the entire perimeter across a landscape. This involves two distinct processes: first, representing the fire perimeter in a manner suitable for simulation, and second, propagating that perimeter in a manner suitable for the perimeter’s representation. Both processes are carried out by Forefire . The Forefire simulation code is based on a discrete event simulation (DEVS)  formalization of a front tracking method. In the front tracking method, the fire line is decomposed into a set of connected points, or markers, like in FARSITE . Each marker is a DEVS  atomic model that has a specific propagation direction and speed, as shown in Figure 2. The speed at which the marker is traveling along its propagation vector is given by the rate of spread of the fire model . The direction of the propagation vector is given by the bisector of the angle formed by the marker with its left and right neighbor’s (see Figure 2). Markers are redistributed along the front if separated by more than the resolution distance and removed if separated by less than . A fire line is defined as a full set of interconnected markers. If two points of different fire lines are separated by less than , the two fronts are merged. The integration of a marker advance is performed in a discrete event manner, with no global time step but specific activation time for markers. Every marker is always advancing by the same distance , estimated from the propagation speed when the marker would travel this distance. The timed activated events are placed in a sorted event list, and the simulation is performed by activating the most imminent event. The method has been selected because of its computational efficiency and its ability to simulate the propagation of an interface at high resolution (submeter) needed to take into account different vegetation, roads, houses, and fire breaks over a large area typical of wildfires (hundreds of square kilometers). Concerning ignition, the fire simulator necessitates defining a burning area (usually a triangle) since it follows a Lagrangian schema. The size of each segment of this polygon is given by the resolution of the numerical perimeter of the simulation. Usually, this resolution (quantum distance ) is 8 meters. Thus, the initial contour is an 8 meters sided equilateral triangle. Decreasing the quantum size does not influence the simulation results but increases the calculation time.
Figure 2: Front tracking and markers. Circles represent markers along the fire line. Arrows show the propagation vector (bisector of the local angle at the marker between the left point and the right point, ). The grey area represents the burned fuel.
3. Case Studies
This section summarizes the findings from the case studies of Favone fire and Suartone fire that occurred in South Corsica coastal region. In the last fifty years, this area was submitted to several catastrophic wildfires which lasted several days and burned thousands hectares of shrub. Most of them occurred in summer under western windy condition, high ambient temperature (greater than 30°), low relative humidity (lower than 30%), low fuel moisture content, and drought conditions. The case studies were selected in this area in order to get simultaneously some of those conditions for which high-intensity fires occurred. Although many of the environmental factors affecting severe fire occurrence have already been recognized , it has been observed that there is not some constant prevailing. There are, rather than that, mixes of several danger variables, that together produce conditions for a major fire to occur. Our aim was to reconstruct wildfires representative of weather and fuel state conditions encountered in severe fires. For both cases, we detail the chronology and behavior of the fire, the environmental conditions (topography and fuel mapping, meteorological data) as well as the suppression activities.
3.1. Favone Fire Case Study
3.1.1. Chronology and Behavior
This (human-caused) fire occurred in South-East Corsica in July 08, 2009 (Figure 3) near the village of Favone (ignition point: lat. 41°45′57.08′′, long. 09°23′44.84′′, 33 m a.s.l.), where about 30 ha were burned. The fire was detected at about 3:00 p.m. in a place (Figure 4(a)), where fuel load was reduced by mechanical treatment. Logs were burned and smoldered causing the Favone fire. The fire spread quickly, moving uphill (Figure 4(b)) and then shifted on the left towards the east driven by a western south-western wind of about 18 km/h in average. A tourist detected the fire and called firefighters. The first crews happened to arrive on scene at 3:05 p.m. within 5 minutes of the fire’s origin. The fire threatened some residential and resort areas on the left flank. Three crews (each crew composed of a pumper truck and men) were deployed to protect these residential and resort areas and to constrain the fire on its left flank. The terrain and fire intensity did not allow a direct suppression attack on the head of fire. At first, aerial resources (four air tankers) worked on the left flank to protect the residential and resort areas and to allow firefighters to be safely deployed. Then, aerial resources worked on the right flank. The idea was to push the fire towards the sea. The fire jumped over the road at 4:00 pm and reached the sea at about 4:15 pm. It was contained at this time by 10 crews deployed to extinguish the edges of the fire front. The fire was mopped up and declared out at 7:00 pm. The fire rate of spread was about 920 m/h between points A and B under upslope condition (see Figure 5) and about 666 m/h between points B and D under downslope condition.
Figure 3: Fire perimeter for the case study of Favone fire (courtesy of South-Corsica firefighters).
Figure 4: Ignition point and subsequent spreading.
Figure 5: Topography, fire perimeter (in black) and vegetation types as defined in Table 1 for the case study of Favone fire.
3.1.2. Site Description
The site is located near the sea. It is slightly hilly with two hills along the path of the fire that do not exceed an altitude of 100 m (Figure 5). The area is characterized by the typical subarid Mediterranean climate, with a remarkable water deficit from May through September and most of the annual rainfall amount occurring in fall and winter. The burned area was composed of three vegetation types (Figure 5): a small part of the area was a woodland of Quercus suber (cork-oak) near the ignition point (9 ha). It is referred to as Oakland 1 in the following. Near the road and the beach (end of the fire, point D in Figure 5), the area was covered by a low typical shrubland Mediterranean vegetation, with plant height of about 1.8 m. This type of vegetation is a Mixture of grass and shrub, up to about 90 percent shrub coverage and 50 percent grass coverage below the shrub. Dominant species included Erica arborea (60%), Phyllirea angustifolia (15%), Myrtus communis (15%), and other species in fewer amounts. This vegetation type is not represented in Figure 5, since it represent a negligible part of the burned area (less than 1 ha). The rest and main part of the burned area was covered by a high typical shrubland Mediterranean vegetation (20 ha), with plant height ranging from 2 to 4 m and a coverage of 100%. Quercus suber were scarcely present in this area. This type of vegetation is referred as Shrubland 2 in the following. There is no grass but a heavy litter of leaves of Arbutus unedo and Quercus suber. Dominant species included Arbutus unedo (50%), Erica arborea (30%), Pistacia lentiscus (10%), and Quercus suber (10%).
3.1.3. Environmental Conditions
Two regimes for wind speed and direction prevail in this area. The first one which is the most frequent is an easterly regime due to a sea breeze effect. It is especially present during daytime in the eastern façade of Corsica. The second one is a westerly regime due to large-scale atmospheric circulation. It takes place mainly during the night and after 4:00 pm when the sea breeze effects cease. The prevailing winds directions during which intense fire occur at the sites are typically west and southwest. It was the case for the Favone fire for which wind velocities varied between 5 and 7 m/s and wind direction ranged from 240° to 270°. Air temperatures varied from 25°C to 27°C during the fire, and relative humidity of air was between 41% and 46 %.
3.2. Suartone Fire Case Study
This site is about 30 km from Favone. Hence, the general description and environmental conditions provided in the previous section are similar. Only the local variation in vegetation and change in meteorological conditions the day of the fire are described in this section.
3.2.1. Chronology and Behavior
This fire occurred in South-East Corsica in July 28, 2003 (Figure 6) near the village of Suartone (ignition point: lat. 41°28′21.93′′, long. 9°13′30.48′′, 40 m a.s.l.) where about 456 ha were burned. The fire was detected at 3:00 p.m. The first crew (pumper truck and men) happened to arrive on scene at 3:15 p.m. within 15 minutes of the fire’s origin. The fire was spreading moderately in an area surrounded by shrubs on the left side of the road. Firefighters could not get near the fire and were too far away to drop water with their water cannon. Then, five more crews arrived on scene. The terrain and fire intensity did not allow the direct suppression attack on the head of fire. All crews were positioned on the road trying to extinguish the fire from their position. Suddenly, due to a local change in wind direction the fire jumped over the road. The right flank of the fire front was about 350–400 m. It became the fire head that accelerated both driven by a western wind of about 30 km/h in average and upslope effect. Then, nearing the village of Suartone the rate of spread of the fire decreased. Aerial resources arrived and dropped water on both flanks of the fire and constrained it. The fire ended when it reached the sea. It was mopped up at 7:00 pm and declared out in the night. The mean spread rate of the fire front between ignition and arrival at the sea was about 1440 m/h. Intermediate velocity was difficult to calculate due to few observations on scene.
Figure 6: Topography, fire perimeter (in black) and vegetation type as defined in Table 1 for the case study of Suartone fire.
3.2.2. Site Description
The site is located near the sea. Ignition occurred at the bottom of a canyon (Figure 6). Then, when the fire jumped over the road, it spread on a hilly area with four hills along the path of fire that do not exceed an altitude of 200 m. The burned area was composed of four vegetation types (Figure 6
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 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.
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.
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.
Tags: backdraft, case study, deliberate practice, Extreme Fire Behavior, firefighter injury, near miss, practical fire dynamics, reading the fire, situational awareness, vent controlled fire
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