A new day has dawned for the American fire service. It did not happen instantly, but gradually. Over time, astute and aware fire service professionals have been monitoring the changes in building construction techniques and materials, the changes in how structures are furnished in terms of Btu...
To access the remainder of this piece of premium content, you must be registered with Firehouse.Already have an account? Login
Register in seconds by connecting with your preferred Social Network:
A new day has dawned for the American fire service. It did not happen instantly, but gradually. Over time, astute and aware fire service professionals have been monitoring the changes in building construction techniques and materials, the changes in how structures are furnished in terms of Btu content and heat release rates, and the similarities between fire events, especially tragic events. Over time these industry sages have been telling us what they have observed. In a November 2008 posting at www.firehouse.com, Ozzie Mirkhah and Sean DeCrane outlined numerous fires across the country where firefighters were killed as a result of the modern fire environment. In "Enter Through the Door, Fall Through the Floor," they described similar events where fire rapidly consumed lightweight construction members and firefighters fell to their deaths.
While these events are nothing new, as stated by Mirkhah and DeCrane, why do these tragic endings continue? Despite warnings from such fire service experts as Brannigan ("The building is your enemy!"), Brennan ("Make the building behave!") and Brunacini ("It's not OK to die at structure fires!"), it seems that the fire service has been slow to respond or, worse yet, slow to find solutions or alternatives to outdated strategies and tactics. What is needed, then, to overcome this apparent information jet lag that the fire service suffers from is a new paradigm.
The first part of this series (July 2009) discussed the problem that the American fire service now faces and that which was reviewed above. The second part (August 2009) discussed the need to know and understand fire behavior in order to quickly recognize the situation and then react appropriately. This final part of the series will outline changes that need to occur in order to respond to structure fires safely and to better affect the annual firefighter death and injury toll by connecting-the-dots and offering a better, safer way to fight fires.
John Norman, retired FDNY deputy assistant chief, wrote in his Fire Officer's Handbook of Tactics, "Modern firefighting is a continually evolving science." Similarly, while our basic strategies of protecting life, confining the fire and extinguishment have not changed, our tactics should, especially if we are students of the game. In our present circumstances, it behooves the fire service to look at all events critically and make the necessary adjustments. This analysis, then, must be constant and ongoing. In this new age, "adapt and overcome" must be our mindset if we are to affect and reverse current firefighter line-of-duty-death trends.
With everything that this series has brought to light, the following is offered as an up-to-date alternative, or a "new-school" approach, to fighting today's fires, especially those involving lightweight construction. With a big-picture view, our current "old-school" fire attack methods are simply not working. Be cautioned, though; there are no claims here that this prescription is the latest silver bullet, but merely a reasonable alternative to current practices. Nor does this new choreography recommend that interior structural firefighting cease, but rather we, as the American fire service, temper our approach with great caution in respect to high-risk situations that our current circumstances present. Smart and aggressive firefighting practices can co-exist on today's fireground, however, and the modern firefighter will know the difference!
Everything in our culture is built around speed of response, but we really need to transition to a more deliberate and cautious response in the name of safety. This approach will most importantly get us to the scene safely, but also better enable us to take in the information that is presented upon arrival. In several ways, speed kills because in our haste to react quickly we miss important clues that will enhance our safety on the fireground.
In a Firehouse® Magazine article, Battalion Chief Mark Emery of the Woodinville, WA, Fire and Life Safety District stated, "The so-called 'fast-attack' mode has no place on the contemporary fireground" ("Grading the Fireground on a Curve," September 2008). Emery continues by stating that safe, effective and meaningful size-ups and action plans cannot be completed quickly and that there is "nothing fast about an intelligent and safe fireground operation." These concepts are also reinforced by William R. Mora, a retired captain from the San Antonio, TX, Fire Department who has authored numerous articles concerning the dangers of fast fire attacks, especially within enclosed buildings.
The slow-down concept should not only be prudent practice, but a frame of mind that will better enable responders to gather important incident information and process it without compromising safety. This approach entails accessing electronic pre-emergency plans enroute, recognizing important clues upon arrival from reading the building, reading the smoke and then making comprehensive size-ups. The slow-down concept also lets responders take a deep breath, collect their thoughts and use discretionary time while making an accurate situation assessment.
Do the "Hot Lap"
Upon arrival, another concept that needs to be completed is a look around the entire structure that is involved. This "hot lap" is also called a "360" or a "circle check," and its importance cannot be overstated. Again, a complete look will provide clues on the building's construction, life hazards and occupancy, the fire location, intensity and potential growth, and other tactical information that will better enable responders to safely tackle the problem.
It can be argued that the fire service has to some degree drifted away from this important practice at the sacrifice of speed or maybe even because of a widely accepted practice of a stationary incident commander. Yet, the absence of a complete hot lap has also been a key component of numerous fire service tragedies, such as the Mary Pang Fire in Seattle, WA, and a building collapse line-of-duty-death in Green Bay, WI. Also, a near miss recently occurred in Loudoun County, VA, where a complete hot lap would have better enabled responders to understand the fire dynamics and the effect on the structure.
A quick hot lap can also be completed with a thermal imaging camera to better look for the seat of the fire. Heat is commonly communicated through Type V, stick-frame buildings and will therefore show up on the imager while viewing from the outside. Responders can also look inside windows for signs of smoke and fire and even note the effects of fire on the structure, especially with basement fires. All of this will better enable responders to make accurate risk assessments.
Decision: Go or No Go
With all of the precautions and clues from above, responders are then better able to make a decision regarding their tactics. A decision may be made toward a defensive approach, or even an offensive approach, but all decisions should be considered through a comprehensive risk assessment. No building is worth the life of a firefighter and while we may sometimes take great risk to save others, we should not be risking our lives to save property only.
With risk in mind, Deputy Chief of Operations John Tippett of the Charleston, SC, Fire Department has likened the engineered, lightweight, glued-wood building components of today as "hydrocarbon impregnated wicks" ("Take a Lap/Walk Around," www.firefighterclosecalls.com, posted May 2008). Tippett also warns firefighters how two-story homes with brick on side A and vinyl siding on sides B, C and D are "widow makers" in fire situations. He reminds firefighters that they should not be surprised at how fast these "solidified, gasoline-wrapped structures" burn.
Therefore, regarding our modern environment and the risk of fire attack, here are some entry preclusion considerations:
- Lightweight construction with significant fire involvement and all residents are outside and accounted for
- Lightweight construction with known or unknown prolonged fire impingement
- Lightweight construction with impending and immediate chance of collapse
Earlier parts of this series discussed the modern fire environment and fire dynamics. The volatility of a fire is predictable, but the actual timeframe has surprised many firefighters. Numerous case studies cite examples of fire situations that grew so fast that even experienced firefighters were caught off guard. There have even been statements to the effect that upon arrival, the fire scene appeared to be "usual" or even "benign," only to change drastically a few minutes later.
The first part in this series also likened a smoke-filled environment to a propane gas cloud in terms of flammability, yet that is the setting that we commit firefighters to every day. With apologies to the great Tom Brennan, who spoke of the need to make the building behave, isn't it more appropriate to make the fire behave? That is, by knowing that fire, being both a chemical and physical event that creates smoke, flammable gases, and heat, shouldn't we take actions to rid the building of the products of fire? That is where effective ventilation practices come in.
While there are structure fire situations where vertical ventilation is both warranted and effective, a best-practice ventilation technique, especially with stick-frame, residential structure fires, is positive-pressure ventilation (PPV). Study after study by the National Institute of Standards and Technology (NIST) and major fire departments have shown the advantages and effectiveness of PPV techniques. The data is nearly incontrovertible, so the only questions that remain concern the application of this technique at fire scenes. Those questions are answered in the "Positive Pressure Attack for Ventilation and Firefighting" book that was mentioned in the first article of this series. (Read this book!)
However, reading the book alone is not necessarily believing, but seeing PPV work is. PPV not only clears the environment of smoke, heat and toxic and flammable gases for firefighters, it also improves survivability for victims. Again, NIST data show the immediate cooling and improvement of atmospheres seconds after PPV was initiated inside structure fire environments. Should not victims be part of the equation here also? Don't we exist to save them as well?
One other noteworthy consideration concerning the victim profile is the effect of applying water streams in a super-heated environment on unprotected victims. What is the chance of their survival when water is converted to steam, much less being in a hot, smoke-filled environment? Not good, according to an unscientific study of over 10,000 firefighters from around the world. The study by Battalion Chiefs Kriss Garcia and Reinhard Kauffmann and retired Firefighter Ray Schelble of the Salt Lake City, UT, Fire Department found that fewer than 1% of victims survive the hostile fire event after water has been applied. Effective PPV practices not only make fire situations safer for firefighters, but also victims.
Finally, proper ventilation before firefighters enter the structure for fire attack greatly diminishes risk, but also makes moot points of debates over the effectiveness of "penciling" and even pulsating fog techniques, and also the age-old debate over fog nozzles versus smooth-bore nozzles. Properly applied, PPV also can eliminate hostile fire events, the dangers of firefighter disorientation and prolonged zero-visibility conditions, and concerns of the dangers with ventilation-controlled fires, especially with our bread-and-butter type of residential fires that we encounter often. Simply stated, remove the dangerous atmosphere in a building and everything gets better.
The Attack-Line Punch
It is commonly accepted around our country that a minimum flow for attack lines should be 150 gpm. Even some national standards recommend that initial responders be able to flow a minimum of 300 gpm from at least two hoselines. But in light of the increased Btu content in our modern fire environment, our new paradigm should use 180 gpm as the minimum flow per attack line. This flow will enable firefighters to hit the fire with an adequate punch at most room-and-content fires, and in combination with other attack lines be able to knock out fires that have begun to assault the structure of residential occupancies.
Reasoning for multiple attack lines depend upon the size of the fire area and the fuel type and load. A rule of thumb for fire-flow has historically been the National Fire Academy (NFA) formula of building length times width divided by three times the percent of involvement. While this basic formula has been used for years, most firefighters are unaware of its existence or how its use can assist with on-scene tactics. The key is to get an adequate flow of water to "kill" the fire.
However, the NFA formula was developed approximately 25 years ago, and as this series has discussed, the fire environment has changed. The noteworthy change has been the heat release rates (HRRs) of furnishings, including furniture and floor, wall and ceiling coverings. HRR is a common method that is used to measure the energy produced from a fire. It is measured in watts, which is joules per second. Since fire involves a great amount of energy, the units can be recorded as kilowatts (1,000 watts) or megawatts (1 million watts). The key concept for firefighters to recognize is that HRR is directly related to the required fire flow for extinguishment.
Consider the following HRRs (sources: "Compartment Firefighting, Part One — Flow Rates" by Paul Grimwood, Fire Magazine, September 2000; Kirk's Fire Investigation, fifth edition, by J.D. DeHaan, 2002, Brady Publishing):
It is also commonly accepted that the average size of a family room is approximately 250 square feet. Assuming that such a room can contain a three-seater sofa, two upholstered chairs and other combustible furnishings, a room-and-contents fire could potentially involve approximately 9.5 megawatts. By the NFA formula alone, the required fire-flow calculates to 83.3 gpm if the room is 100% involved, yet, it can easily be recognized that this flow is woefully inadequate and even unsafe. The question that surfaces, then, is how much fire-flow would be required to extinguish a 9.5-megawatt fire in an average-size living area?
Grimwood, a retired London firefighter, answered the fire-flow question in his September 2000 article in Fire Magazine. Grimwood wrote that water has a theoretical cooling capacity of 2.6 megawatts per liter per second (l/s), but in reality, in terms of applying cooling water to object(s) on fire, can absorb only 0.84 mW/l/s when applied on fire attacks. When square footage is factored in, and with a conversion of metric units to English units, here is the energy produced by modern living-area fires and the required fire flows:
Based on these calculations, it can be observed that the NFA fire-flow formula needs to be updated. Suffice it to say that the required fire-flow in the 21st century is more along the lines of 70% of the area of fire involvement.
Another overlooked aspect of fire-flow capability is the use of a Class A foam water additive. Water additives have been referred to as "voodoo science" over the years because of the mystery of how surfactants work along with eduction practices and calculations. Many firefighters are baffled by Class A foam, much less Class B, foam operations, but in reality they are quite simple. For the purposes of structural fire attack, Class A foam additives make water more effective. That is, water becomes "wetter" and can penetrate materials more easily, which assists with extinguishment and helps to prevent post-extinguishment flare-ups.
Manufacturers of Class A foam recommend eduction at 0.5%, but the additive begins to make water wetter at 0.1% to 0.2% eduction rates. In other words, a little Class A foam educted into a hoseline goes a long way. Consequently, Class A foam additives are inexpensive, yet they greatly aid in our firefighting capabilities. It should be the standard practice to use Class A foam additive for all structure fire operations.
With the proper flow to hit the modern-day fire, Class A foam additives properly educted and the smart approach to committing to an aggressive fire attack, the next step is the execution. That is where practice, determination and discipline pay off. Generally speaking, extinguishing the fire makes other problems go away.
It's Your Call
With everything above being considered and applied, firefighters should be able to reduce their risk, save more property and save more lives, including both the publics' and their own, much more readily in today's modern fire environment. Smart firefighters will recognize that their worksites have changed, especially for lightweight-construction residential fires, and they will react accordingly. In short order, new tactics for these frequent fire events should affect our profession's safety statistics.
DAVID F. PETERSON is a lieutenant in the Madison, WI, Fire Department, where he is the lead fire and hazmat training officer. He is in his 30th year as an emergency responder. Peterson is enrolled in the National Fire Academy's Executive Fire Officer program and is a master instructor for the International Association of Fire Fighters (IAFF). He is the managing member of the Wisconsin FLAME Group LLC, a leadership and management company, and operates www.hazmatpetie.com, a hazardous materials response training website. Please send your comments and questions to him at www.hazmatpetie.com or firstname.lastname@example.org.
|Enroute||Consult electronic pre-plan of involved structure|
|Arrival||Size-up, assume command |
Devise and communicate initial tactical plan and assignments (rescue victims if needed)
|"Hot Lap"||With a thermal imaging camera, completely circle structure |
Look for hot spots, seat of fire location and exit points
|Risk assessment||Decide to go or no-go! (Risk/benefit analysis)|
|Ventilate||Exhaust point made for ventilation, PPV blower readied|
|Adjustments||Decide if initial plan needs to be altered|
|Attack Line||Select suitable attack line with adequate flow along with Class A foam|
|Area (in sq. ft.)||GPM required||mW cooling capacity||Attack lines needed|
|Chair||Small upholstered||150 to 250 kW|
|Christmas tree||Six feet, dry||1.0 to 3.0 mW|
|Gasoline||Two-liter pool on concrete||1.0 mW|
|Mattress||Cotton||100 to 970 kW|
|Queen-size (PU foam) with covers||2.0 to 4.0 mW|
|Pine bunk bed||4.5 mW|
|Small trash can||300 kW|