October 16th, 2008
What is the difference between a fairy tale and a firehouse tale?
Fairy tales generally begin with once upon a time, while firehouse tales begin with you wouldn’t believe what happened last shift and no, this really happened. This post begins with a firehouse tale.
A crew of firefighters advances a 1 1/2 “hoseline up a stairwell in a large wood frame house. The second floor is well involved, and the smoke level is down close to the floor. The young firefighter with the nozzle indicates that it is too hot to advance onto the fire floor. The officer moves up close to the nozzle and evaluates conditions, finding that the firefighter is correct. The officer calls the incident commander and asks for ventilation to raise the smoke level and relieve some of the heat that is preventing advancement onto the fire floor and an attack on the fire. Moments later, the officer is enveloped in fire and feels himself flying backward through the air. This ends when he slams into a hard surface. Everything is black, and he is unable to see. It is not hot, and eventually, he sees a glimmer of sunlight. Attempting to remove his breathing apparatus facepiece, he experiences discomfort in both shoulders, but is able to pull the facepiece off, discovering that the darkness was caused by blackening of the exterior of his facepiece lens. The building is still well involved, the hoseline extended through the front door, but the crew of firefighters that was with the officer are nowhere to be seen. The officer pulls his facepiece back on and crawls back in along the hoseline, finding the firefighters frantically trying to make the fire floor, thinking that their officer had been blown down the hallway instead of up and over their heads, balling down the stairwell behind them and rolling out into the street. The officer withdraws his crew as other crews extend hoselines to the second floor, and extinguish the fire.
In this incident, the officer with the hoseline was unaware that significant indicators of a potential backdraft in an enclosed section of the second floor were visible from the rear of the structure (where the incident commander and the crew performing horizontal ventilation were located). The effects of the backdraft were serous but could have been much worse. The officer received minor burns, injured both shoulders, and severely damaged his facepiece and turnout coat. What made this incident worse was that it occurred during live fire training with a group of recruit firefighters.
I know that this firehouse tale really did happen as I was the officer in the story. This incident occurred in the late 1970s while I was working for the Massachusetts Firefighting Academy as a part-time instructor. Unfortunately, while academy staff investigated this incident, the outcome of this investigation did not impact substantively on training practices, and at the time, the academy staff did not widely communicate lessons learned.
How many of you have had a close encounter with extreme fire behavior? One where you said that was close or you suffered a minor injury? What did you learn and how did you share this information?
Often, as in this backdraft incident, those involved learn a valuable lesson, but do not share the information beyond the firefighters and officers they work with. Many things have changed since the 1970s. One is the existence of National Fire Protection Association 1403 Standard on Live Fire Training Evolutions. While not perfect (but that is another topic for discussion), it identifies systems of work that increase the safety of participants engaged in live fire training. Another, more recent change was the development of the National Firefighter Near Miss Reporting System. This system leverages the advantage of the World Wide Web to provide the ability to report near miss incidents and widely share our lessons learned. If you have been involved in or witnessed a near miss incident or have been told of the event, you can anonymously submit a report and share what you have learned.
The data submitted to the Near Miss Reporting System does not go into a vacuum. Following review, and removal of information which would identify the agency involved, reports are posted in a searchable database on the firefighternearmiss.com website.
This program is a tremendous resource! the Visit the site and search on flashover (38 reports), backdraft (9 reports), rapid fire progress (4 reports), or smoke explosion (33 reports). Remember, this database contains self-reported information. This does not make it less useful. In many ways it is more useful than distilled and analyzed information presented in other types of reports (particularly when the individual was involved in or witnessed the event). However, there may be technical inaccuracies (particularly with regards to extreme fire behavior phenomena) and the lessons learned by the individual who submitted the report may or may not be what you want to take away. Read the reports, think about the factors that influenced the occurrence of the event, how it could have been prevented, trapped or mitigated, and draw your own conclusions.
If you are involved in, witness, or are told about a near miss event, report it. The more information in the database, the greater the potential to identify patterns of causal factors and develop strategies for improving firefighter safety.
Ed Hartin, MS, EFO, MIFireE, CFO
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Tags: Extreme Fire Behavior, lessons learned, near miss
Posted in Extreme Fire Behavior, Random Thoughts | No Comments »
Near Misses, Injuries, and Fatalities, Just Part of the Job?
October 13th, 2008
In 2007, twenty firefighters in North America lost their lives due to extreme fire behavior while engaged in interior structural firefighting operations. The United States Fire Administration Report 2007 Firefighter Fatalities in the United States and the NFPA Report Firefighter Fatalities in the United States-2007 provide analysis of firefighter fatalities that occurred during this year. Neither report specifically addressed the issue of firefighter fatalities as a result of extreme fire behavior. In fact the NFPA report classified a significant number of these fatalities as being the result of structural collapse (despite the fact that collapse occurred some time after rapid fire development trapped the firefighters involved).
Thus far in 2008, eight more firefighters have died due to extreme fire behavior while working inside burning buildings. This is the tip of the iceberg! Since January 2008, there have been several incidents in which rapid fire progress trapped multiple firefighters. In each of these incidents the firefighters escaped with serious injuries.
· May 25, 2008 – Four firefighters trapped on the second floor by a flashover, Loudon County, Virginia
· October 7, 2008 – Four firefighters trapped on the second floor by a flashover, Sacramento, California
In What’s Changed Over the Last 30 Years, Fahy, LaBlanc, and Molis state that the rate of traumatic fatalities while engaged in offensive firefighting operations inside burning building has been increasing.
In many cases, extreme fire behavior is a causal or contributing factor. It is critical that firefighters understand compartment fire behavior and can apply that knowledge to maintain situational awareness and make effective decisions on the fireground. Fire behavior training for most firefighters and fire officers is limited to a few hours during recruit academy and possibly brief mention during tactical training. This is not adequate!
At the 2008 International Association of Fire Chiefs Conference in Denver, Colorado, Chief Fire Officer Charlie Hendry of Kent Fire Rescue Service and President of the United Kingdom (UK) Chief Fire Officers Association discussed a number of significant incidents that impacted his nation’s fire service. One of these incidents was a backdraft in townhouse apartment in rural Wales that killed Firefighters Kevin Lane and Stephen Griffin. This incident and the subsequent investigation by the British Fire Brigades Union and the Health and Safety Executive identified major training deficiencies, resulting in changes in fire behavior training across the UK. For a brief overview of the incident and discussion of its impact on the UK fire service, see Blaina: A Perpetual Legacy.
Where is the recognition that the American fire service faces the same problem on an even larger scale?
What can we do, individually and collectively to address this issue? I will be writing about this topic for the next couple of weeks. Add a comment to this post with your ideas!
Ed Hartin, MS, EFO, MIFireE, CFO
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Tags: Extreme Fire Behavior, Fire Behavior Training, firefighter fatality, firefighter injury
Posted in Extreme Fire Behavior, Fire Behavior Training | No Comments »
Hazard of Ventilation Controlled Fires
October 9th, 2008
In the Grading the Fireground on a Curve, published in the September issue of Firehouse magazine, Battalion Chief Mark Emery warned of the hazards of assuming that limited volume and velocity of visible smoke indicates a growth stage fire. He correctly identified that compartment fires may enter the decay phase as fuel is consumed or due to a lack of oxygen.
Emery cites National Institute for Occupational Safety and Health (NIOSH) Death in the Line of Duty reports 98-F07 and F2004-14, in which firefighters initiated offensive fire attack in commercial buildings and encountered rapidly deteriorating fire conditions due to changes in the ventilation profile. Concluding the introduction to his article, Emery observes “Unless you know which side of the fire growth curve you are entering, advancing into zero-visibility conditions is really a bad idea”.
I agree with BC Emery’s basic premise that appearances can be deceiving. However, this article points to two interrelated issues. The hazards presented by ventilation controlled fires and the dangerous conditions presented by enclosed buildings. In Smoke Burns,originally published on Firehouse.com I discussed the hazards of ventilation controlled fire and the relationship of burning regime to extreme fire behavior phenomena such as flashover and backdraft. The hazards presented by ventilation controlled fires are compounded when the fire occurs in an enclosed structure (a building with limited means of access and egress). Captain Willie Mora has written extensively on Enclosed Structure Disorientation on Firehouse.com.
BC Emery illustrated how appearances can be deceiving using data and still images from a full scale fire test in a warehouse in Phoenix, Arizona conducted by the National Institute for Standards and Technology (NIST). NIST conducted these tests as part of a research project on structural collapse. However, the video footage and temperature data from this test is extremely useful in studying the influence of ventilation on fire behavior and fire behavior indicators (Building, Smoke, Air Track, Heat, and Flame (B-SAHF)). The full report and video from this test is available on-line from the NIST Building Fire Research Laboratory (BFRS).
As an oxidation reaction, combustion requires oxygen to transform the chemical potential energy in fuel to thermal energy. If a developing compartment fire becomes ventilation controlled, with heat release rate limited by the oxygen available in the compartment, pyrolysis will continue as long as temperature in the compartment is above several hundred degrees Celsius. Pyrolysis products in smoke are gas phase fuel ready to burn. Increased ventilation at this point, may cause the fire to quickly transition to the fully developed stage (ventilation induced flashover). However, if the fire continues to burn in a ventilation controlled state and the concentration of gas phase fuel (pyrolysis products and flammable products of incomplete combustion) increases sufficiently, increased ventilation may result in a backdraft.
I take issue with BC Emery’s illustration of the growth side of the fire development curve as the value side of the cure and the decay side of the curve as the no value side of the curve. Depending on resources, a fire on the growth side of the curve may exceed the offensive fire control capability of the fire department. Conversely, a fire on the decay side of the curve which is limited to a single compartment or series of compartments may be effectively controlled using an appropriate tactics in an offensive strategic mode. However, Emery’s discussion of the more subtle indicators of burning regime that may warn firefighters of a ventilation controlled fire is right on track. For more information on fire behavior indicators and fire development, see Fire Behavior Indicators and Fire Development Parts I and II on Firehouse.com.
Ed Hartin, MS, EFO, MIFireE, CFO
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Tags: backdraft, burning regime, fire behavior, fire development, flashover, vent controlled fire
Posted in Extreme Fire Behavior, Reviews, Tactical Ventilation | No Comments »
Positive Pressure Ventilation: Theory and Practice
October 5th, 2008
Many firefighters consider Positive Pressure Ventilation (PPV) to be a new tactical approach, despite practical application in the United States since the 1980s. Since its inception, PPV has strong advocates and equally strong opponents. In many cases these opinions sprang from observation of inappropriate application of PPV without a sound understanding of how this tactic actually works. Early on there was little scientific research integrated with practical application of PPV tactics.
However, over the last six years the National Institute of Standards and Technology (NIST) has been conducting an ongoing program of research to identify how PPC works, factors influencing effectiveness in varied applications, and best practices in the application of this tactic. Steve Kerber served as principal investigator on this project. Steve is a fire protection engineer (who also serves as a volunteer Chief Officer in Prince Georges County, Maryland). Steve authored an excellent article titled NIST Goes Back to School published in the September/October issue of NFPA Journal.
This article provides a brief overview of the NIST research on PPV to date and outlines a series of tests conducted in a two-story, 300,000-square-foot (27,871-square-meter) retired high school in Toledo, Ohio, to examine the ability of PPV fans to limit smoke spread or to remove smoke from desired areas in a large low-rise structure.
Steve pointed out the effectiveness of appropriate use of PPV as demonstrated in this series of tests, observing:
In this limited series of experiments the pressure was increased sufficiently to: reduce temperatures, giving potential occupants a more survivable environment and increase fire fighter safety, limit smoke spread, keeping additional parts of the structure safe for occupants and undamaged and reducing the scale of the emergency for the fire fighters, and increase visibility, allowing occupants a better chance to self evacuate and providing fire fighters with an easier atmosphere to operate in. Positive pressure ventilation is a tool the fire service can utilize to make their job safer and more efficient.