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MFA #23: Protecting Egress - And other hoseline placement myths

Coming to terms with the significant changes to firefighting tactics wrought by fire behavior researchers and the innovative implementors of their findings is an ongoing process, and there are repeated instances when the new information that has filtered into our understanding again changes our perspective.  This enlightenment is also cumulative, and even exponential, as the same knowledge is applied to other aspects of our craft, and it becomes steadily clearer that much of what we believed, taught and practiced was well-meant, but incorrect.  The revisions to our understanding of fire behavior, specifically how combustion within a building responds to air and water flow, impacts a variety of our tactics that were based on the previous, disproven interpretations.  

One such reconsideration involves the "rules" for the positioning and use of hoselines.  For instance, virtually every firefighting textbook, lecturer, and SOP has specified that the first hoseline should be positioned between the fire and the unburned portion of the structure, both to drive the fire away and to "protect the path of egress”.  I would argue that our new knowledge of fire dynamics indicates that the first hoseline should be stretched to where a stream can most quickly be directed into a compartment containing burning material.  This may still be via the front door, or around to the side or rear of the structure, or even from the front yard.  The intent is to get water on the fire as soon as possible, which, in turn, will immediately improve conditions throughout the structure.  Even if the burning involves several rooms, yet only one is immediately accessible, live fire experiments have shown that the profound cooling that results from water application to that single room will extend to those adjacent.

As you might have expected, the recommendations for positioning the second hoseline will also need to change.  Already a ripe topic for debate, varied and learned opinions include having it follow the route of the first as a backup, covering the most severe exposure, or even leaving it up to the IC (i.e., no “rule” for placement of the second line; just make sure you always have one).  The MFA approach would be that the second hoseline goes with the firefighting crew that enters the building.  (I know; Duh!)  If the first line already was taken into the structure to reach the seat of the fire, because that was the most direct route, it could not be located from the exterior, or it was on an upper story and out of reach of hand-operated streams, then I would default to the “it depends” rule for the second, and direct it to where it is determined to be the most useful for that situation. 

While accepting these tactical revisions may induce head explosions for some traditional fire tactic advocates, actually implementing them would be relatively easy.  Placing and operating an exterior hose stream can be accomplished by a single firefighter, leaving the rest of the crew to ready themselves for entry once the 30 seconds or so flow of water is completed.  (Two members on the outside line would be better, allowing for one to assist with line placement and to clear an opening, and a two-person initial line crew could then be the "two-out" portion of an OSHA-compliant fireground team as they would be available for such duty in short order.)  Since the exterior line is flowed for just a brief period - less than a minute - it can either be repositioned to support entry or, even more efficiently, merely left on the ground once shut down.  Deploying two lines should not be a problem from any NFPA 1901-compliant (i.e., "stock") Engine and, with only one flowing water at a time, would also not strain the water supply any more than a single line (and, given the efficiency of being able to first cool the fire room from the exterior, might actually result in reduced water flow requirements).  The two-line method could also be utilized even if there were only minimal staffing.  

In fact, this is the technique practiced by Hanover (VA) Fire and EMS, the initial proving ground for the SLICE-RS approach: the first line is stretched to the fire location and flows water to accomplish immediate interior cooling, while a second is taken to the point of entry.  After initial water application, the exterior line is usually shut down and left in place, thereby eliminating the difficulties and delays in repositioning a charged hoseline.  In the event that a single, 3-member Engine Company arrives on the scene of a reported entrapped victim and the two firefighters elect to make immediate entry, then the Engineer (driver) will place and operate an exterior hoseline to provide the rapid interior cooling.  The point is, the improvement in conditions is both so significant, and often so easy to accomplish, that it can be reckless not to first flow water!

Another hoseline placement myth is the whole notion that it is necessary, or even helpful, to place a hoseline between the burned and unburned portions of a building.  The concept of putting ourselves between the fire and the victims/unburned property inside a burning structure is powerful and romantic, but unfounded and unnecessary.  While it is certainly a valid tactic for outside fires (as in wildlands, or when fires are threatening to spread to other buildings), and it remains critical that firefighters enter and search a burning structure as soon as possible (See MFA #16: The Rescue Imperative at http://community.fireengineering.com/profiles/blog/show?xg_source=a...), structure fires are extinguished by the application of water to the burning material, and the direction from which that water flow occurs - from outside to inside/burned side to unburned side, or visa versa - has no bearing. 

In previous postings, I have attempted to debunk the claimed hazards of exterior streams (MFA #17: The Steaming Victims Issue at http://community.fireengineering.com/profiles/blog/show?xg_source=a...) and benefits of interior streams (MFA #18: Like Herding Bees with a Hoseline at http://community.fireengineering.com/profiles/blog/show?xg_source=a...).  We don't push away fire in a structure with our hose streams, and the presence of our hoseline in a doorway certainly doesn't make it easier for occupants to exit.  For basement fires, protecting the upper floors was the longstanding rationale for stretching a line to the top of the basement stairs, but the Governors Island (GI) experiments found no significant improvements from flowing water down those stairs into a burning cellar.  Substantial cooling, on the other hand, was accomplished with streams directed through cellar windows or, better yet, exterior doorways, indicating much more effective targets for the initial hoseline.  

 

The final water application tactical revision that follows from fire dynamics studies, including more than a few NIOSH LODD investigations, is the need to abandon our compulsion to get to the "seat" of the fire before water flow is started.  Certainly, the burning fuel needs to be extinguished sooner rather than later, but the fire compartment - the area within the structure, both including and remote from the fire, in which heat and smoke has accumulated - will respond rapidly, significantly, and extensively when water is introduced anywhere within.  Especially if there was no opportunity to first apply water to the fire from the exterior, the entering nozzle operator should periodically spray water into any overhead smoke and observe for evidence of excessive heat.  This will be indicated by the immediate vaporization of the hose stream, announced through loud “sizzling”, which should signal the nozzle operator to flow additional water until that effect ceases.  Cooling the overhead gases in this way prevents flashover while improving conditions far beyond the reach of the hose stream.  The lack of excessive overhead temperature will result in the hose stream merely bouncing off the ceiling and falling to the floor, at which time the nozzle can then quickly be shut down and the hoseline advanced. 

We use water to cool the products of combustion as soon as possible, and until we can reach the burning material itself and complete extinguishment.  Sometimes we are fortunate enough to be able to accomplish both from the same position, and other times we need to reposition to complete the process.  As I proclaimed in my initial posting on this subject (MFA#1: Unlearning at http://community.fireengineering.com/profiles/blog/show?xg_source=a...), firefighting has just got a lot easier, except for anyone who already knows how to fight fires.  These refinements in the use of our primary tool - the hoseline - are simple changes, based on sound science, and represent yet more examples of why the modern fire service is in desperate need of new textbooks.

MJC

The author can be reached at markjcotter@comcast.net

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