By Ron Kanterman
New Fire Loads
We’ve been discussing new fire loads for about 15 years because we’re not going to our fathers’ fires anymore. Battalion Chief Dave Dodson’s “Art of Reading Smoke,” program appears on the 4th edition of the Everyone Goes Home DVD and tells us: “Forget what you’ve learned about the fact that fire grows exponentially–2, 4, 8, 16, 32 times, and so on– and that flashover is at 1,400°F. Fires are growing to flashover in a matter of seconds in some cases, and the temperatures are near the 1,900° to 2,000°Flevel.” Chief Dodson is right and the science is backing up what he’s saying.
My guess is that most of you have seen these types of fires firsthand over the past few years. From the 1980s and even earlier, jet-black smoke and deep-orange flames blowing out the windows of a building most often signified “a pour” (a term for an arson fire for anyone born after 1990). Of course, if the roof was already involved, the asphalt would be contributing to that black-and-orange pattern, but from the windows, it signified something else. The color of the smoke and flames was a result of the hydrocarbons burning and aiding the standard Class A combustibles in the structure toward rapid pyrolysis.
Once noted, fire officers and firefighters adjusted their tactics to include a larger line, perhaps because there were more British thermal units (Btus) and a hotter fire, and the immediate awareness that the fire was an “on purpose” and not an accident. Most arsonists wanted (and still want) the building to burn all the way down so they might put things in our way or make it harder for us to operate. It was little things such as sawing the stair treads halfway through so when you and your buddies were in the middle of the staircase, it would break through and send you the basement via the express route. They also hung plastic bottles of gasoline from the ceiling to accelerate the fire as you got inside. Great group of guys, huh? We had enough problems with operational safely; we certainly didn’t need that.
Today’s fire loads could be equated to the “booby traps” of the past because of the greater heat release rate (HRR) of the materials. The average house fire today looks like the old “pour” fires of yesterday. They have a ton of hydrocarbon-based materials, and the average commercial building has two tons. In the past, we were taught that the color of the smoke was some indication of what was on fire: grey smoke was an indication of an incipient fire with cloth or paper involved; brown smoke gave us a hint that dry, structural wood was involved; and, of course, black signified hydrocarbons or the roof, as previously mentioned. Since most fires are showing black smoke off the bat, the color of the smoke is no longer a reliable arson indicator, but it does demonstrate that our hydrocarbon load is heavier than ever. If you look around your house, they’re easy to spot: TV, computer, furniture coverings, furniture stuffing (polyurethane foam cushions covered with vinyl), laminate counters, laminate cabinets, polyester carpeting and drapes, the kids’ toys, stereos, 500 CDs in a tower holder, hardwired phones (I’m an old guy), cell phones, fax machines, printers, among other things. In addition, there’s wood furniture framing, a breakfront or show case, wood handrails, a bed post or two, a dining room set, clothing, newspapers and magazines–and again, other things. Don’t forget that all of this stuff may be in buildings of lightweight wood construction. Today we see new homes that are larger, have more open-floor plans, vaulted ceilings, “great rooms,” and overall less compartmentation. These so called “McMansions” are filled with interconnected void spaces that enable a room-and-contents fire to quickly become a structure fire. One thing that old-style balloon-frame Victorian, Queen Anne-type homes and other old homes with basements have in common with the new stuff is the increased fire load. On top of all this, you may have “hoarders” or, for you seasoned vets out there, “Collyer’s Mansion conditions.”
This proliferation of synthetic materials is occurring at a time when structures are becoming more vulnerable to rapid fire spread and collapse. We now know that engineered lumber fails rapidly as compared to the dimensional “legacy” lumber of the past. Perhaps attempting the extinguishment of these types of fires far exceeds what a 1¾-inch hoseline can deliver. Fire loads have changed, and we must make adjustments in the interest of community fire protection and the safety of our members.
Bread-and-Butter Fires
So, knowing what we now know based on firefighters’ firsthand experiences and science, consider the following: For many years, we attacked structure fires, house fires, and fires in smaller buildings with 1½-inch hoselines that gave us 125 gallons per minute (gpm). It worked well for its time and for the fires we were fighting in that era. Necessity drove the fire service to evolve and go to 1¾-inch lines, which delivered more water with the same amount of effort, because the fire loads were starting to change. Some departments around the nation over the past 20 years even went to 2-inch hose and are getting even more water with a tad more effort than wrestling with a 1¾-inch line.
We know what we need to do. So why not do it? Why not consider that when you have more than one room of hydrocarbon-laden materials on fire, take a
2½-inch line with a smooth-bore nozzle into the house (staffing permitting)? Why not look at it like a commercial fire? The new fire loads are putting out more Btus than ever before. The fires are hotter, producing more energy than ever before, and more fierce. Let’s give ourselves a better chance at knockdown/cool-down.
What else can we do? My 20 years in industrial fire protection made me a true believer in three things: a lot of water real fast, foam, and dry chemical. With all this talk about transitional attack and limited staffing, we need to look at things through a different set of glasses. Picture this: You pull up with three people on your engine and two on your truck. Fire is blowing out the front two widows of the first-floor bedroom. What if a member of the truck crew took a 20-pound ABC dry chemical fire extinguisher and emptied it into the window while the engine crew was stretching to the front door?
Fire Extinguisher Standards
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Underwriters Laboratories (UL) is the organization that developed the standards for fire extinguishers in the United States, based on effectiveness and safety. The ratings on an ABC multipurpose dry chemical (ammonium phosphate) fire extinguisher will usually weigh heavily toward the BC side of the unit. Portable units are available up to a “20A120BC” rating. The A rating is based on a “1A” unit, which contains 1¼ gallons of water. A 2½-gallon water can is rated “2A.” A “10A” rated unit should put out four times more fire than a 2A unit. UL used wood crib fires at different dimensions to create the ratings. A “10B” rated unit is rated for a 25-square-foot pan of flammable liquid (31 gallons of heptane in an 8-inch deep pan.) A “40B” rated unit should extinguish a 100-square-foot pan containing 125 gallons of heptane. NOTE: Flow rates vary from one-third pound per second to 2½-pounds per second. An average 20-pound dry chem unit will give you a total discharge in 20 to 30 seconds. |
The “A” part of the dry chemical will give the fire a slap. The “BC” part will give it a punch, particularly for those pesky plastics we’ve been talking about. This solves two problems and/or answers two questions. You will no doubt get some knockdown right away. This will buy time for occupant escape and fire department entry. For those of you who believe that you can or will push the fire with your line if you put it in the window to knock down the fire before you go in, there’s no pushing here. A circular motion in the window and 20 pounds of dry chem won’t push anything. I’m not suggesting we tie down the handle and lob dry chemical units into the windows of buildings like the old fire grenades, but it’s time to get creative. Don’t forget two things, however. You don’t get any cooling from the dry chemical, but you will get a chemical reaction and an interruption in the fourth side of the old fire tetrahedron (the continuing-chain reaction side) to stop or slow the fire. The dry chem will stick to the surfaces and retard ignition. That’s what it’s designed to do.
Let’s say the dry chemical thing is too far out of the tactical box for you (even though I asked you to smash it for the sake of this article) because it’s not water-based and we love water and water-based stuff. For those of you who have a compressed air foam system (CAFS) on your rigs, you already know the benefit of using foam in structures and other places. Foam holds the water where it’s applied and causes it to soak in to the burning materials rather than run off. There is almost no runoff when using CAFS as opposed to water lines, which create rivers or water features cascading down the stairs of a private home. We also know that most fire departments have some class B foam for a flammable liquid fire.
Can we put class B foam in a structure? We already know most of the place is full of hydrocarbons or solid petroleum, so why not? Foam is water with its specific gravity changed, right? If you drill a few times and get the practice of “break the line and place the foam proportioner with the pick-up tube and foam pail in the middle” thing down cold, you’re ahead of the game. You may also be able to get out of doing all that work, because most modern day rigs have a 50- or 60-gallon foam cell with a preconnected line. Consider stretching this line at a working fire first to achieve a quick knockdown from the outside or the inside. A quick circular motion for perhaps 15 or 30 seconds will accomplish this. Then head inside and go to water for final extinguishment–or not. With a built-in foam cell, it’s usually takes only the turn of a valve or the closing of a gate to switch between water and foam production. If your engine has the capability to proportion your Class B foam down from 3 or 6 percent to 1 percent, you’re in Class A foam land! I know some of you are thinking “budget” at this point. Water is cheap and easy to get in most places, and there’s usually plenty of it. But if you use your foam wisely, you’ll make it work.
In light of limited career staffing or the lack of volunteers, here are some recommendations:
- Volunteers: Consider using these tactics during the day when staffing is light.
- Career departments: Consider these methods when deemed necessary.
- All: Look at these tactics as a matter of regular practice. Get out and try them in an acquired structure or burn building.
Foam and Sprinklers
In November 2001, my article “Put the Foam Where, Chief?” was published in Fire Engineering. It was about thinking outside the box specifically when fighting flammable liquid fires. I worked on an industrial site in which flammable liquids were in just about every building. My foam salesman also said foam will work on deep-seated Class A fires. We were looking for new and innovative ways to fight fire.
With the amount of hydrocarbon fires we’re battling in today’s structures, might the same train of thought make sense? We know the qualities of Class B foam and how they work on flammable liquid fires; however, it will work on Class A fires as well (it’s water, remember?). Am I supporting taking a foam line into a structure yet again? If you have a lot of hydrocarbon-based fire, solid or otherwise, foam is the answer.
Just to try it, my last command and I experimented with a fixed system at the local fire academy burn building. The sprinkler heads were regular 165° heads with ½-inch orifices, found in most commercial buildings, stores, offices, schools, and so on. They were not foam spray heads designed specifically for foam. There were lengthy discussions in the past about aspirating or aerating foam (injecting air into the foam), particularly out of a nozzle of a handline. The new aqueous film-forming foam (AFFF) doesn’t need much to work right, and we found that the sprinkler deflectors did a good job of aerating the foam on discharge. The old foams needed aspiration, but not so much when it comes to the modern concentrates. In fact, we pushed finished foam solution through the fire department connection (FDC) to the two sprinklers and extinguished a 5 × 5 pan with four liters of hexane with a three- to four-minute preburn time in under a minute.
Think what you might accomplish at a large commercial building or a big box store by pushing foam out of the sprinklers as opposed to plain old water. It will do well on the Class A materials because of its inherent qualities (low surface tension), where it has the ability to cling to surfaces and soak in to the materials as well as cover them. As we know, water has a high surface tension; only about 10 percent of the water you apply actually extinguishes the fire (consider the cascading stairwell water feature mentioned earlier in the article).
Consider a big-box store and do a mental walk-around of a large home center. What do you see? Paints and thinners, carpet rolls, flooring, and an indoor lumber yard, for starters. Now imagine a large furniture store full of solid hydrocarbons (coverings, foam rubber pillows over wood framing, and so on) stacked to the ceiling. Take a look around your district and see where you may consider putting a foam line into the FDC or a 2½-inch foam line in your hands. It can be a preconnected line if you have a foam cell on your apparatus, or it can be made up in the street with lines, pails, and a pick-up tube. Take a look at what you have, play with it, test it, and come up with a plan. Depending on your foam educator, pump pressures may exceed the system pressure, which could lead to some problems. In most cases, however you should get good results just from what you carry on your engine. The only way to find out is to try it and then mark your preplans accordingly. In addition, work with the facility owners to see if you can affix a permanent sign listing pump pressures and other important data at or near the FDC for that 0300-hour fire.
Sample First Due Preplan or Quick Action Plan (QAP)
Address: 100 Main Street
Business: Feldman’s Furniture Outlet
Building: 100 × 300
Hydrant: IFO building main entrance
Sprinklers: YES
FDC: Corner of Walk and Don’t Walk (SE)
First Due: Foam line to the sprinkler system for knockdown.
2 ½-inch hoseline in the door for mop-up and final extinguishment.
Shut sprinklers upon entry of crew.
NOTE: Shutting sprinklers must be a coordinated activity and be done only by order of the incident commander. There are many cases in the books showing a premature closing of sprinkler valves that resulted in a large-loss fire–e.g., General Motors Transmission Plant in Livonia, Michigan, in 1953. For some unexplained reason, a security guard shut the sprinklers even before the fire department arrived and burned the plant down, resulting in a $100 million loss. Fighting fires in sprinklered buildings requires a different strategy.
Mutual Aid: Transmit a second alarm.
Add whatever else you think is important. Not all of your preplans may look like this. Include foam or even the aforementioned dry chemical. Start with your target hazards and then your bread-and-butter jobs, and go from there.
Foam and Standpipes
In 2006, we were thinking about our new 133-foot high-rise flammable liquid process building and how we were going to get foam to the upper floors. Of course, the first thing was to look at a tower ladder with a foam system (yes, they do exist–in fact, most refineries have them.) We had all of the manufacturers bring us demo models, and we drove them around the plant, set them up numerous times, and had our entire department drooling at the prospect of having a tower ladder with a foam system. This was at about the same time we were thinking about putting foam into the sprinklers as noted above.
One day while the building was under construction, we took the rig to the building, connected a line to the FDC, and pumped the standpipe system with foam. First we used plain water to flush the lines through an open butt hose. We put the nozzle back on (a typical spinning tooth, adjustable fog nozzle) and then called for foam. We made perfect foam on the top floor of the building with little or no effort. The “typical” nozzle we used aerated the foam just enough to be effective. This experiment along with the foam in the sprinkler system made us change our standard operating guidelines (SOGs). On responding to an automatic alarm or worse in any of our process buildings, a foam line was run to the FDC for the sprinkler and/or standpipe systems. You can start with water and then simply open the foam valve if needed. Again, this will work on deep-seated, stubborn Class A fires better than water. By the way, we never purchased the foam tower ladder. We were disappointed (not getting a rig), but we had already found the best way to go about protecting the facility. Needless to say that although they were ready and willing to buy this rig, management was extremely happy. They saved $1.2 million in 2006 dollars.
Summary
- Buildings are loaded with hydrocarbons, solid petroleum, and so on.
- Consider a 2½-inch line with a smooth bore nozzle vs. a 1¾-inch line for multiple rooms of fire because of high heat and Btus and the new open floor plans.
- Consider a foam line instead of plain old water inside the structure.
- Consider dry chemical for exterior rapid knockdown.
- Consider foam for exterior rapid knockdown.
- Consider pumping foam into sprinkler systems.
- Consider pumping foam into standpipe systems.
- Try these methods and see what works for you.
Should this be your part of your SOGs or standard operating procedures? Should you start carrying 20-pound ABC dry chemical units on your rigs for quick knockdown? Should you stretch a foam line into an out-of-control residential or commercial fire? Start thinking about using alternate extinguishing media on stubborn hot hydrocarbon-loaded fires. It’s all about knockdown, confinement, containment, and the safety of our people. Work smarter not harder. Work safely, think safety, and get everyone home after the job.
Bibliography
Dodson, David W. The Art of Reading Smoke. Pennwell Publishing. 2007.
Federal Emergency Management Agency/U.S. Fire Administration/National Fire Academy. “Fire Protection Systems for Emergency Operations.” Course #N227.
Fire Engineering Handbook for Firefighter I & II. G. Corbett, Ed. Fire Engineering/Pennwell. 2009.
International Association of Fire Chiefs and National fire Protection Association. Industrial Fire Brigade, Principles and Practices. Jones and Bartlett. 2008.
Kanterman, Ronald. “Put the Foam Where, Chief?” Fire Engineering. November 2001.
Ron Kanterman is a 37-year veteran of the fire service. He holds a bachelor’s and two master’s degrees and is a career fire chief in southeast Connecticut. He is an advocate for the National Fallen Firefighters Foundation and serves as chief of operations for the annual Memorial Weekend ceremonies each year in Emmitsburg, Maryland. He teaches graduate and undergraduate fire science and lectures each year at FDIC and on a variety of topics around the country. He can be reached at mfdcar1@comcast.net.
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