WHY FIRES ARE MORE
|By Andrew A. Fredericks|
By Ted Corporandy
While medical responses have increased our call volume, we should not forget that responding to fires is, after all, our primary mission. The next time you are at headquarters take a moment to look at the wall displaying the names of those San Francisco firefighters who made the supreme sacrifice. They died at fires, not medical calls. Medical training receives significant attention, as it should, but not at the expense of fire training. Nationwide the incidence of fire is supposedly on the decrease, yet the death and injury rate has not declined. The point here is that the fire environment is becoming increasingly more complex with a greater potential for death and injury. Unless we understand this and prepare for it by training and remaining tactically up-to-date, we are flirting with disaster. A friend of mine, Andy Fredericks, a firefighter with the Fire Department of New York City has kindly allowed me to reprint a recent article he wrote for the web magazine, Firenuggets.com. I hope you find it insightful and thought provoking. In order to establish his credibility for those who have not heard of him, I am presenting his qualifications, much to his embarrassment, I am sure. Andy is a nationally renowned authority on engine company operations, hoseline stretches, and nozzle selection. He has written extensively for Fire Engineering magazine and has authored a number of training videos. He is a co-author of FDNYs engine company operations manual and a New York State certified fire instructor at the Rockland County Fire Training Center in Pomona, NY, an adjunct instructor at the New York State Academy of Fire Science, a field instructor for the Illinois Fire Service Institute, an instructor for the New York State Association of Fire Chiefs, and an adjunct lecturer at John Jay College of Criminal Justice in New York City. He is a member of the Editorial Advisory Board of Fire Engineering and the FDIC Educational Advisory Board. Andy holds a bachelor of arts in political science, a bachelor of science in public safety/fire science, and a masters degree in fire protection management.
For several years now we have been told that fires are more dangeroushotter, less predictablethan they were 50 or even 25 years ago. The primary reason given for this is the ever-expanding use of plastics in our homes and businesses. Others have countered that this is simply not true, because it is the available oxygen that regulates the heat produced by any compartment (room) fire. For each cubic foot of oxygen consumed in the combustion processregardless of the fuel involveda fairly uniform 535 Btus of heat is produced. Since all interior fires are oxygen or ventilation regulated, in theory, the heat produced by burning a one-pound block of polystyrene will be almost exactly the same as the heat produced by burning a one-pound block of oak.
The problem with this explanation, however, and one of the reasons why fires are more dangerous today, is that it ignores differences in the heat release rates of plastics and traditional or cellulosic fuels. Plastics, in general, have much higher heat release rates. Early in the development of a compartment fire, it is not the oxygen available for consumption that controls the burning rate, but the characteristics of the fuel itself. If the materials burning have higher rates of heat release, we can expect a more rapid build up of heat within the fire area and a reduced time frame until a flashover or other rapid fire development event occurs. As Tom Brennan points out: fires maybe fewer today (compared to the peak fire activity years of the 1970s), but the incidence of flashover is greater. The dangers posed to firefighters operating in this volatile environment are very real. But an increasing number of flashovers is only part of the story. Smoke conditions have worsened as well.
The dark, choking smoke characteristic of fires involving petrochemicals has become a signature of the modern structure fire as petrochemical derivatives (plastics) now represent the single greatest portion of residential and commercial fire loads. One of the dangers posed by volumes of dense smoke is the ease with which a firefighter or team of firefighters can become disoriented and lost. Incidences of firefighters becoming lost in the smoke and subsequently dying from asphyxiation or from burns caused by rapid fire spread have become tragically common. In some cases, the firefighters had a charged handline with them when they entered the burning structure, but somehow became separated from the line and subsequently died. In other cases, firefighters have been severely burned while clinging to the handline and the reason for this phenomenon requires a closer look at smoke and its makeup.
Smoke is made up of solid particulates and aerosols carried along by convected air and carbon monoxide gas. When you ask firefighters about carbon monoxide (CO) and its attendant hazards, most will reply by rote that its colorless, odorless, and tasteless. While these characteristics are important, there are three others that cause death and injury to operating firefighters: CO is highly flammable; it has a wide explosive range (12.5% to 74%); it ignites at about 1,128 degrees Fahrenheit (a temperature quickly attained in many room fires). Although the lower explosive limit (LEL) of CO is high when compared to other flammable gases, once the LEL is achieved, CO remains within its flammable limits over a wide range of fireground conditions.
When pockets of CO ignite, firefighters performing searches and even those advancing handlines are often burned. Insulated by modern bunker gear and protective hoods from the heat radiating downward from the smoke above them and blinded to rollover by the dark smoke that surrounds them, the critical warning signs of impending flashover go unnoticed. Even state of the art turnout clothing cannot protect against burns caused by flashover. Remember too that a charged handline cant offer protection if it isnt in operation. Perhaps opening the nozzle on smoke, despite what we have been taught, is something we should consider in some cases. If we can reduce the volatility of the smoke, we can prevent burn injuries. Fires involving commercial occupancies, cellars, and confined spaces should be considered prime candidates for applying water on smoke.
Still another issue involves the types of buildings and structures we fight fires in today. Void spaces are commonplace in new construction. Voids have also become a problem in buildings that are renovated using lightweight components and assemblies. Voids create ideal places for CO to collect and build-up dangerous temperatures and pressures that often result in collapse, smoke explosions or other rapid fire progress events. Buildings are also more insulated today and smoke and heat seepage to the outside is often eliminated. Without benefit of a fire that has self vented prior to the arrival of the first due fire companies, firefighters are frequently subjected to extreme punishment while performing primary search duties and advancing the initial attack handline.
So it is truefires are more dangerous today. Unfortunately, both human evolution and fireground tactics havent kept pace with changes in the modern fireground environment and advances in modern turnout gear. Firefighters still get burned at the same temperatures today as generation ago. Although modern protective clothing has reduced the incidence of many types of burns, when firefighters do get burned, the severity is often very high. Aggressive interior fire attack is the hallmark of a good fire department yet in an increasing number of instances, it is incompatible with the volatile, well-insulated, lightweight fireground of today. What then, is the answer?
It is not one answer, but several. Here are five to start with.
First, lets restore firefighting to its proper place at the head of the fire department table. Service diversity has in many cases created mediocrity on the fireground. Second, lets utilize our protective equipment wisely and gain a better understanding of its limitationsphysical, physiological, and psychological. Third, lets train more realistically. Use acquired structures whenever possible and forget the propane simulators and theater smoke. Fourth, make sure we know how much water were flowing on our fires. The only way to do this is to measure it and make sure we are achieving minimum flows and reach with manageable nozzle reaction burdens. Fifth, increase staffing. As retired FDNY Deputy Chief Vincent Dunn has pointed out, we often have most of our too few personnel on the fireground assigned to every task imaginable except stretching and operating the life saving first handline. Amen for NFPA 1710. The road just ahead may be a little rocky, but the long-term benefits will be tremendous. Until next timestay low and stay safe!