From my perspective – that being someone who entered the fire service just as the era of “surround and drown” was being replaced by the “get in and hit it up close” approach – the most immediate and practical operational change inspired by fire dynamics research is the early application of water. While the recommendation to delay ventilation also has significant benefits – and loud critics – “opening up”, especially vertically, was a tactic that many of us who worked in small departments with limited staffing often performed only belatedly. We were exceptionally disciplined, though, about passing showing fire with a charged hoseline in order to instead enter through a doorway and extinguish the fire “correctly”, often stretching that same line down a smoke-filled hallway without flowing water until we reached the “seat of the fire”.
Our previous motivations to comply with this indirect approach were the mistaken beliefs that water flow from the exterior was both potentially harmful, driving as it would products of combustion throughout the structure; and less beneficial, with no significant effects expected on any fire in rooms beyond the immediate area of water application. Spraying water into smoke was dismissed as a waste of time and a “rookie mistake”. The almost complete elimination of these concerns, in repeated demonstrations, involving varied combinations and arrangements of compartments, has, in effect, provided us with a powerful new method for fire extinguishment. It has removed a significant, misguided, self-imposed restraint on our collective behavior; an edict that we had accepted so completely that we would enthusiastically defend our actions when questioned by a non-firefighter (a civilian or a cop) as to why we were ignoring the fire spewing from the windows, and instead taking the time to find, and often force, a door that might be located on the opposite side of the building. Unfortunately, that same level of conviction continues to be demonstrated by many in the fire service who still do not accept this new advice as sound.
Research performed by the non-profit Underwriters Laboratories (UL) and the federal government’s National Institutes of Standards and Technology (NIST) showed conclusively that straight or solid streams directed into a compartment containing fire do not entrain sufficient air to over-pressurize a room and cause heat, smoke and steam to be pushed further inward, as long as the nozzle is not moved about so as to also block those same products of combustion from exiting. Instead, the tremendous cooling effect of the water leads to a contraction of what had just previously been an expanding cloud of badness. Furthermore, the reduction of heat from water application is transmitted throughout the adjacent open areas of the entire involved structure: corridors, common areas, or any room with an open door. Just like a fire in one room will quickly send heat and smoke to all contiguous areas, the reverse also holds true as cooling one or more of those areas will, in turn, absorb the heat energy being spread, and result in cooling throughout the building. Of course, applying water directly to the burning material is still required to complete extinguishment, and as soon as possible. Still, even just cooling the hot gases emanating from the involved area will temporarily (for several minutes) improve conditions. Often, given the heat production from the burning of modern furnishings, this early application of water is a mandatory step in order to be able to reach the seat of the fire, regardless of the quality of a firefighter’s PPE, training, or “aggressiveness”.
All of this having been said many times previously, I have to admit that I’m tiring of repeating the same information regarding the benefits of applying water early and delaying ventilation until after the fire is cooled, and, more than likely, many of you are tired of hearing me recite these same mantras So, in this blog, I will avoid further promotion of basic tenets, and instead move on to discussing the practical use of external streams. (Those readers who still disagree with the whole MFA concept might find something else to read from here on.) Prompting me to focus on this aspect were the repeated instances I have viewed of firefighters who attempted to implement the external stream maneuver, but with less-than-optimal technique, leading to predictably disappointing results. (While many of these examples have been brought to my attention via the internet, I have intentionally declined to provide links to specific videos as I found it too easy to fall into the trap of criticizing the actions of fire crews as they attempted to address complex, dangerous, evolving hazards while I sat and watched it all unfold on a computer screen. Instead, I will leave it to the reader to apply the concepts here discussed to their analysis of events, whether experienced first-hand or vicariously through various media, and draw their own conclusions.)
What particularly bothers me are those situations where the nozzle operator was ordered to attack a fire from the exterior, and yet did so in such a timid, haphazard, and/or ill-performed manner as to have little effect on the fire within. I have seen videos of heavy fire showing from the “B” side of a single-story home, some 20 feet from firefighters with a charged hoseline, who were instead waiting for the door on the “A” side to be forced. When directed to apply water to the fire, they moved just beyond the A-B corner to enable their stream to reach the emanating flames, succeeding in merely cooling the air outside the building, while ensuring they could quickly return to their prior position once the door was opened; or burned through. At many such incidents, the focus on entering through a doorway allowed the fire to extend and enlarge significantly, with no additional benefit derived from the eventual success in accessing the preferred entry point.
This is the result of firefighters knowing, or at least believing in, only one way to extinguish a fire. Such weak attempts at utilizing exterior streams represent the most glaring example of a failure of the Aggressive Interior Attack (AIA) mindset; the counterpoint to the traditionalists’ concern that firefighters will “waste time” seeking an exterior path to the fire and delay building entry. Eddie Buchanan, one of the initiators of the SLICE-RS approach, said it best when he explained that the best route to the fire is the quickest route, and it does not matter if that is a hose stream directed through a window, or one that was dragged through a door remote from the fire and down an interior hallway. “Whoever gets to the fire first wins!” In that vein, the proper descriptive term for our preferred approach should be merely “Aggressive Attack”, as the ideal (quickest, easiest) direction (interior or exterior) must be determined anew for each situation.
At other fires, well-positioned exterior streams – that is, placed directly in front of a first- or second-story window in which flames can be seen – show them being moved about continuously to extinguish burning window frames, siding, soffits, and, again, the flames already outside the building, but with only brief applications of water directly into the involved compartment. This “Restless Stream Syndrome” is a comprehensive but ineffective hose stream application. While wetting all involved and threatened areas is a natural, and recommended, response to being confronted by multiple sites of burning and soon-to-be burning material, it must not be the sole focus of the nozzle operator. Until water is flowed into the compartment at a sufficient rate to overcome the amount of heat being produced – and this might take just 15 seconds with a handline – there will be no reduction in the progress of the fire.
To find instruction as to how to best to apply water from outside a building, we need merely go to the Governors Island videos at http://www.firecompanies.com/modernfirebehavior/governors%20island%20online%20course/story_html5.html
In these experiments, total water application into the burning structure lasted from just 15 to 60 seconds, flowing from 45 to 180 gallons. Straight stream patterns were utilized to minimize both any obstruction of the opening to exiting products of combustion and the entrainment of air. The water flow was also directed upwards when possible, best accomplished when doors or windows were above grade, in order to directly cool the hottest gases that are highest in the room, as well as to strike the ceiling of the compartment and cause water to rain down onto any burning contents. This dual effect – cooling the smoke and, when reachable, the burning contents – is very effective at reducing temperatures significantly, extensively, and persistently. In the basement fire experiments, where the doors and windows were “on grade”, breaking up the stream by hitting the ceiling was neither feasible nor, as it turns out, entirely necessary, with significant temperature reductions accomplished regardless.
Still, while the proper technique is simple and effective, it is neither intuitive nor foolproof. Therefore, it requires training and practice in its execution. It goes beyond handing a firefighter a charged hoseline and pointing her/him toward a burning building. The fireground is not the appropriate venue for introducing, practicing, and refining these, or any other, new skills. The first step is the necessity of ensuring that a solid or straight stream is selected, which, in the case of a combination nozzle, is determined by briefly flowing the line while it is aimed elsewhere than the fire compartment. Secondly, directing the stream to quickly extinguish any materials burning on the outside of the structure in order to halt fire extension via exterior paths (through soffits, higher windows, etc.) remains a vital step, though, to state again, not a complete goal. Thirdly, angling the stream upward in order to reach the upper layers of heat and smoke, and to have the stream contact the ceiling to break it into smaller droplets, optimizes its beneficial effects. Finally, continuing the flow of water for at least 15 seconds while leaving the nozzle immobile is key, although longer water applications will have only improved effects.
Again, the recommended method for operating an exterior stream is relatively simple. The difficulty lies in it being both the exact opposite of the methods on which most of us have been taught, trained, and drilled, requiring us to overcome long-ingrained habits; as well as intentionally minimalist (i.e., point it into the window and don’t move it for at least 15 seconds), even unnaturally so, contradicting as it does firefighters’ apparently innate tendency to constantly move a stream about. This combination leaves us with an approach that is more than a little challenging to accept and perform, yet one that is well worth the effort. While it should go without saying, I’ll say it anyway: Whatever technique is used for firefighting, it must be performed correctly!
Exterior streams might be viewed as a new tactic, or “another tool for the toolbox”, though an old tool which had been neglected might be a more accurate metaphor. Since every firefighter already has this tool available, we are all obligated to become proficient in its use, and to understand its indications, limitations, and execution, in case a specific instance presents where it may be the best approach – like, maybe, at your next structure fire. It’s certainly not difficult: the use of a straight or solid stream, kept in one position, or at least repositioned only slowly, quickly and extensively cools the compartment into which water is flowed, and allows products of combustion, even as they cool, to continue venting from the same opening. On the other hand, whipping a stream about will have a similar effect to applying a fog pattern to the window, increasing the pressure in the compartment, and potentially forcing those same gases deeper into the structure if a flow path exists.
Choosing the right tool for the job must not be a result of habit, bias, or laziness, but a decision made after a careful analysis of the factors at play at each incident. Exterior streams often have distinct advantages (e.g., speed, ease, and safety) over interior streams in the results that count – halting fire growth – and need not slow, nor be slowed by, the continued need to enter involved buildings for search and completing fire extinguishment. In fact, the application of water from the exterior can enhance the success of interior operations by providing immediate, significant, and prolonged cooling, buying additional time for potential victims.
The author can be reached at firstname.lastname@example.org