By P.J. Norwood and Frank Ricci
Scientific research and data are critical to increasing our understanding of the dynamic environments we face as firefighters. However, it is important that the message does not get lost in the noise. While the fire service is attempting to reconcile the findings of the Underwriters Laboratories (UL) and National Institute of Safety and Technology (NIST) studies, we will focus on the practical application of this technology.
The new information is not as scary as it seems. What we consider new is based on tactical pieces of the puzzle experienced truck and rescue companies have been practicing for years. We are not talking about the engine member who rides the truck and gets his first taste of breaking windows indiscriminately! We are talking about the need for coordinating venting and the limiting of venting. There is no change; tactical discipline is and has always been critical in controlling the building. What we are learning is that it is even more important than we thought and that the fire behavior model of the past is not the same as the model of today.
As we discuss the UL and the NIST studies, we are finding that the latest science has just given us the full picture to link understanding and improving on our tactical disposition.
Terminology is critical to understanding. However, just because an event has a new name doesn’t mean it is something altogether different. A fuel-limited fire is no different from a fire that is producing high volumes of smoke, the type of fire during which firefighters were taught not to break windows until the line was applying water. We have called this “keeping it rich.” We should continue this practice, but now we have a better understanding of the implications of our actions and inactions. The fact is that the fire environment has become less forgiving. As an example, in truck school, we were taught not to vent before applying water. We have all witnessed a member taking windows indiscriminately in violation of this rule and getting away with it. Now, we are seeing that these faults are resulting in catastrophic consequences.
We all understand that building construction and home contents have changed. Furniture has become the equivalent of solid-state gasoline. Long gone are the days of wood and natural fibers. What some may not understand is how today’s contents and building materials are affecting fire behavior.
The traditional fire behavior model we all learned to understand is outlined in Figure 1. below courtesy of UL’s Firefighter Safety and Research Institute.
Figure 1. Traditional Fire Behavior, Fuel-Limited Fire
The traditional fire behavior model still works today for a fuel-limited fire as for a pile of pallets in your department’s burn building. However, most of the fires we face today are not fuel limited. Today, we are experiencing a fire behavior model as illustrated in Figure 2.
Figure 2. Typical Structural Fire Behavior, Ventilation-Limited Fire
Today’s fires are becoming ventilation limited, which, at times, occurs before the first companies arrive. Therefore, when we force entry, a window fails, or air is introduced into the structure, we see a rapid acceleration of energy and heat. During the many UL tests, it was found that the time from ventilation to untenable conditions in a one-story home was 1 minute, 40 seconds; in a two-story home, it was 3 minutes, 20 seconds. Both scenarios should be used as an order of magnitude, as times can be shorter or longer based on circumstances. Remember, ventilation is any action that allows smoke out of and air into the structure. When air is allowed in or out of a structure, we are feeding the flow path and increasing the energy of the fire. Note: A ventilation-limited fire is one in which the heat release rate and fire growth are regulated by the available oxygen within the space. (Fire Department of New York [FDNY] Procedures, Vol 1, book 10.)
Outside Vent Team
When venting for fire, you must apply the water before your team takes out windows. Once water is applied to the main body of fire, the first windows to be taken should be in the fire room, and then work back. Indiscriminately venting before the fire is being controlled could create untenable conditions, forcing the attack crew out of the building. This is especially dangerous if you vent behind the line, lighting up the entire hallway. Smoke is fuel waiting for you to make a mistake.
(1) No additional windows should be taken until signs of suppression are visible. (Photos courtesy of author.)
In photo 1, for example, venting additional windows before the line is applied could result in a ventilation-induced flashover. Temperature increase can be greater than 1,000°F. You must coordinate this action; you must be patient and have vent discipline. You can coordinate by radio or by paying attention to the signs of suppression.
Recommendation 1: When venting for fire, you must have the attack line in place at the main body of fire.
The flow path affects “keeping rich.” Flow path is defined as the movement of heat and smoke from the higher pressure area within the fire area toward the lower-pressure areas accessible by doors, widow openings, and roof structures. Generally, unless the thermal layering is disturbed, hot air travels out on top and cool air travels in on the bottom. It is critical that you understand what the flow path is and the potential results of being within the flow path.
Heated fire gases are moving toward the low-pressure areas; based on varying buildingdesigns and the available ventilation openings (doors, windows, and so on). The fire’s energy is pulling in additional oxygen from the low-pressure areas. Note that there may be several flow paths within a structure. Any operations conducted in an uncontrolled flow path without an attempt to limit the velocity of the flow path could place the members at significant risk because of an increase in the movement of the fire (heat and smoke toward their position). The speed of convention heat and smoke has been measured at up to 15 miles per hour (mph). You cannot outcrawl the flow path. Therefore, you could become trapped within this hostile environment, sustaining serious injuries or even death.
(2) The door still must be controlled in the almost closed position. The line stretched in must be charged. Stationing a firefighter at the door is the recommended practice.
Recommendation 2: By controlling the flow path and the amount of air entrained in the structure, you are limiting the amount of energy available for the fire.
Recommendation 3: Stretch a charged line from the point of entry on the fire floor. There is no excuse to stretch dry on the fire floor.
Experienced firefighters have considered flow path without even knowing it while performing the truck search and vent-enter-search (VES) for years. Many truck firefighters have been closing doors during their unprotected search. Yes, we now call it “vent-enter-isolate-search” (VEIS) to be clear. VES and door control have been part of that tactic for more than a decade. When conducting conventional search tactics, make the flow path your primary consideration. Since 2007, we have advocated on a national level that when the firefighter enters a bedroom, he must close the door behind him. The fire cannot tell the difference between VEIS and conventional tactics. There are also many advantages to closing the door. First, it creates an area of refuge. Second, when you or your partner vents for life, no flow path will be created. The smoke in the room will also lift, reducing carbon monoxide (CO), hydrogen cyanide (HCN), and a host of other nasty actors. Visibility will increase, facilitating a quicker search.
When you open the door, you are now in a flow path. If the line is in place and applying water, you can chock the door open to aid in ventilation. If the line is not in place, have your partner leapfrog into another bedroom and close the door to the room (which is already searched), and move to your partner’s new area of refuge. By closing doors and conducting protective searches, we should see a reduction in the number of firefighters forced to bail out windows.
Recommendation 4: The old tactic of checking for deteriorating conditions with the door to the room being searched open should be taken out of the books.
Recommendation 5: When venting for life, you must be able to isolate your position. If you cannot, you cannot vent windows. Note that in most cases, this means windows in the kitchen and living room cannot be vented until water is being applied to the fire.
(An instructional video on Hostile Search is at http://bit.ly/1AGk404.)
Hostile searches typically consist of bathroom and fire room searches that pose a higher risk because of a lack of egress and proximity to the fire. Fire Department of New York’s Vincent Dunn taught us not to go farther than five feet when flashover is possible. The rule is based on how the average firefighter crawls 2½ feet per second. That is equivalent to 1.7 miles per hour (mph). As previously stated, flow path can travel at speeds of up to 15 mph. We do not recommend conducting a free search without having a guarantee that you can control the door to the room. Plastics are producing high volumes of black smoke, makingvisibility even more limited than in the past. Rollover used to be a reliable sign of impending flashover, but now we find that this sign can be masked by black smoke.
Figure 3. Hostile Search
Recommendation 6: When conducting a hostile search, hook your foot on the doorframe. This way, if conditions deteriorate rapidly, you will not miss the opportunity to close the door.
Fire Attack and the Truck
This piece to this new understanding also involves the front door or the forced, open door used to facilitate the fire attack. This door, like the interior doors, must be controlled and closed as much as possible to limit the amount of air entrained into the fire environment. Now, you may be saying, “You want me to close the front door behind my fire attack crew? There is no way I am going to block their means of egress behind them.” Don’t fret; the Los Angeles City (CA) Fire Department has adopted a policy to have a control firefighter placed at the door. The policy calls for the hand light to be stationed at the opening. This firefighter manages the door and pulls more line to facilitate a clean stretch. Another option that is commercially available which manufacturers are now selling is, essentially, a door curtain that controls the flow path without limiting the ability to safely egress, thus robbing energy from the fire (photo 3).
See photo 4: courtesy of Tempest Technology
(3) Courtesy of Tempest Technology Corporation and John Schafer www.greenmaltese.com.
Many Some “truckies” advocate forcing the door to the fire apartment and holding it closed or controlling it until the line is ready to enter. This practice should be commonplace now. For an apartment or a tenement fire, holding the apartment door closed until the line is ready also gives the truck or rescue time to clear the stairs. However, those same truckies (me included) entering a house would often leave and chock open the door with little regard for timing the engine advance. Again, these “new” tactics are not necessarily new. We are now putting the pieces of the puzzle together based on our new understanding.
Recommendation 7: If the truck enters the home, they must control the door or hang a curtain to limit energy to the fire.
If the truck is going to locate the fire for the engine, they must manage the flow path to maintain safety margins. Remember, if the hose team enters the home and opens the door wide, it can influence the fire’s growth in the area where the truck is operating. The engine officer is responsible for communicating changes to the truck or the rescue.
The truck can play a pivotal role by closing the door to the fire room. This action will have the biggest impact on the flow path and will stall or reset the fire. We saw this firsthand when filming the ventilation portion of the Tactical Perspective DVD series. We had a room fully involved in fire and venting out of two failed windows. When the truck crew closed a louver door to the room and called for the line, the fire stalled, flames turned to smoke, and heat levels dropped rapidly.
(4) A firefighter moves to close the door to stall and contain the fire.
Recommendation 8: Do not crowd the hall or stairways. Conditions can change rapidly.
Modern Structure Fire Attack
We have all been taught that offensive strategy is fighting fire from within the building and defensive operations are done from outside. We agree with Daniel Madrzykowski and Steve Kerber that this mentality needs to change! If you are moving in toward the fire, you should be calling this offensive. When you are backing up and moving away, then you are in a defensive position. Why does defensive and offensive attack have to be defined from the location from which water is being flowed? As aggressive firefighters, we all accept an inherent risk in our professions. However, every day we take steps to make our job safer: We wear seat belts, wear new and improved turnout clothing, and we wear our self-contained breathing apparatus (SCBA) in any toxic environment. Yet, too many firefighters and fire officers continue to fall back on their original training, which was “Get in, get close, and get the wet stuff on the red stuff!”
That may have worked for you in the past, and it still may work in the majority of the fires today. However, analyzing the flow path and conditions is a must for all firefighters andofficers. Getting in close has very little benefit; all members should use the reach of the stream to increase safe operations. Potential energy should be reduced before we put firefighters in the flow path. Many feel this is a new concept, but the blitz attack has been around for more years than I have been in the fire service. It’s not all that new! Today, some call it “blitz,” “hitting it hard from the yard,” “transitional attack”, and many other catchy phrases. However, whatever you call it, you are still on the offensive as long as you are moving forward.
(5) Fire envelopes the front of a building.
(6) Crews sweep the front of a building with a deck gun to stall the energy while initial handlines are being stretched to the front door to begin an interior attack.
(7) Hitting the fire head on.
Recommendation 9: Attacking the fire from the outside is acceptable as long as no crews are already inside and you are moving forward. Note the crew in Photo 4 used the reach of the stream to knock down the fire on the eaves and then advanced.
Firefighters across the country must weigh the risk of operating in the flow path without limiting the energy available to the fire. Some departments cannot stage a firefighter at the door to control the door because they cannot purchase new products to perform this skill. Some departments and some fires don’t allow for water to flow onto the seat of the firewithin the time frames stated earlier before the environment became untenable. This does not mean we chalk it up as, “Well, we do what we can do…. We have done it this way for years, and it has worked.” Short-staffed fire departments that do not call for additional help at a working fire are failing to lead and keep your personnel safe.
Recommendation 10: Find a way to take the energy out of the fire. You must attack the fire from the outside before moving in.
Blitz attacks or hitting it hard from the yard is not a defensive operation. Additionally, it is not a tactic where you flow water indiscriminately from the outside until the fire goes out and all the smoke clears. It is a 10-second application of water through the window or the door to reset the fire or to take away the energy. This is done so you can safely go in and make a complete extinguishment. Again, this is not a defensive tactic; it is an offensive tactic to keep your firefighters safe.
Departments from cities such as New York; Washington, D.C.; Los Angeles; Detroit; and New Haven, Connecticut, have been hitting the fire from the outside and moving in quickly whenever they are faced with a fire blowing out of the front door. This tactic has proven effective and has demonstrated that fire cannot be pushed by water. In most cities, going around to the back door and pushing the fire out is not an option. You would have to go through an adjoining building, fake out a dog, break down a fence, or move around cars while the fire is getting bigger. It is also important to size up the fire; not all fires require hitting it from the outside. If you stay outside the fire, it will continue to burn in remote locations and in the voids. Thus, you will lose the building and victims. UL and NIST proved this observation through exhausting scientific research. It would behoove you to take the time to read it and view it on line. (http://ulfirefightersafety.com/)
Water does not push fire; air and ventilation do.
That water does not move fire was a surprise to us. We were always taught to make a hard push when fire is blowing out the front door; my experience backed up this move. However, I have also been on the inside when a hose stream was placed in a window, and I felt as if the sky were falling. The research indicates that placing a line in the window can change the flow path and disrupt the thermal layering.
Perception can also differ from reality. In the NIST and UL studies featuring the Fire Department of New York in real occupancies, the heat increase was measured only at a maximum of 10°F. When wearing heat-saturated gear and a hood, a 10°F bump feels drastic. The hose stream will also lower visibility and move debris. In addition, the force of the stream can injure firefighters. With this new knowledge, we now know that a quick outside application of water from a handline will not endanger possible victims. The reduction in energy outweighs any risk from a handline stream.
Recommendation 11: Combining defensive and offensive tactics while crews are inside is still a bad idea and can result in injury.
Playing Water on Smoke
Many of us have been taught, “Never flow water on smoke.” If you haven’t figured this out yet, let us be the first to tell you. We were trained based on the experience of others and thefire behavior model of a fuel-controlled fire. Most fires today require us to take the energy, limiting the chances of the smoke igniting. When it comes to playing water on smoke, the circumstances will dictate your actions.
Size-up is key if the smoke is not superheated and endangering your position; applying water will only increase water damage. If the smoke is angry and moving quickly, it may be necessary to reduce the energy by hitting it with water. Limiting the flow path is critical in all operations. Some of the tactical implications are not “new.” However, some necessitate smart aggressive firefighting that limits the flow path and prevent the environment that is too rich to reach the right oxygen-to-fuel mixture from lighting off. Keep It Rich!
Photo (8) Smoke is fuel and when heated, as seen here, requires hitting the fire, controlling the flow path, and playing water on this smoke to reduce the energy available to the fire.
The last issue we must touch on is vertical ventilation. There are some firefighters andofficers who have familiarized themselves with the studies. Many have attended classes, read articles, and participated in webcasts. Some of those fire service members have determined that because of what they have read or translated and the presence of lightweight construction, today’s firefighters should not ventilate roofs. We disagree with this thought process based on research, knowledge, and experience. However, vertical ventilation cannot be a random skill performed at will without communicating with the attack crew. Vertical ventilation still has a place on today’s fireground. However, the roof team must perform just as the outside vent team taking the windows. The roof team must not push down the ceiling until the attack line is in place at the main body of fire and flowing water. With a fire that has penetrated into the attic space, the hole can be cut as crews are stretching. However, the roof covering should not be pulled until the line is in place and extinguishment has begun.
Today’s fireground must be better choreographed! Firefighter, officers and chiefs must coordinate and communicate all tactics to keep the members safe!
Special thanks to Steve Kerber, UL Firefighter Safety Research Institute, and Deputy Chief FDNY George Healy for their input on this article.
P.J. NORWOOD is a deputy chief -training officer for the East Haven (CT) Fire Department and has served four years with the Connecticut Army National Guard. He has authoredDispatch, Handling the Mayday (Fire Engineering Books and Videos, 2012), coauthoredTactical Perspectives of Ventilation and Mayday DVDs (2011, 2012), and was a key contributor to the Tactical Perspectives DVD series. Norwood is an FDIC instructor, contributor to Fire Engineering, co-creator of Fire Engineering’s weekly video blogs “The Job,” and hosts a Fire Engineering Blog Talk Radio show. He serves on the UL Technical Panel for the Study of Residential Attic Fire Mitigation Tactics and Exterior Fire Spread Hazards on Fire Fighter Safety. He has lectures internationally and is certified to the instructor II, officer III, and paramedic levels.
FRANK RICCI is a contributing editor and advisory board member for Fire Engineering. He is a lieutenant in the New Haven (CT) Fire Department and co-host of the radio show “Politics & Tactics.” He contributed to the Safety and Survival chapter for Fire Engineering Handbook for Firefighting I and II (PennWell 2008). He was the project manager for Emergency Training Solutions for the Firefighters Handbook I & II Power Point presentations. He has been an FDIC hot instructor and lecturer. He won a landmark case before the U.S. Supreme Court, has testified before Congress, and has been a lead consultant for Yale on several studies. He has worked on a heavy rescue unit covering Bethesda and Chevy Chase, Maryland, and was a “student live in” at station 31 in Rockville, Maryland. He appears in Fire Engineering’s digital blog The Job and developed the Fire Engineering film Smoke Showing. He co-created Fire Engineering’s Tactical Building Blocksposter series and is featured in several Training Minute segments. He authored several DVDs including Firefighter Survival Techniques and Fire Engineering’s Tactical Perspectives series: Command, Ventilation, Search Mayday, Fire Attack, and Dispatchers Handling the Mayday.