I have long been an opponent of the use of PPV to support initial fire attack in single family, garden apartment and other similar structure fires. The basis for my opposition is that in order to properly coordinate the PPV support of a fire attack, units must share a common operational picture and the pathways of anticipated air movements must be known. You cannot simply stick a fan at the door, let it blow and hope that the fluid movement you are now influencing will go as you anticipate.
Despite my opposition to the use of PPV on smaller structures, I am an advocate of PPV use on high-rise fires. NIST has recently published a report on such use and has a seminar on fire behavior planned, one that I think will include the use of PPV to support or assist fire attack.
The short of it is that a fire in a high-rise residential structure presents challenges that are on the outer edge of normal operations. There is no other common circumstance that puts that many people at that much risk so quickly. Even a fire on a top floor has the potential to quickly fill the primary evacuation pathways with deadly smoke and greater than IDLH levels of carbon monoxide. While my experience says that the actual fire rarely leaves the apartment of origin, the smoke finds a way to travel great distances and has a huge impact on operations.
A few weeks ago I was in charge of a fire in a residential high-rise building, one that occurred on the top floor and with a report of multiple persons trapped. I elected to take a non-standard approach to the fire and learned a few lessons in the process. But before I get to the lessons that I learned, I would first like to discuss the theoretical basis for my decision making.
The theory
Arguably our biggest enemy in a high-rise fire is smoke. Even with residential sprinklers smoke spreads, and with it comes carbon monoxide and other deadly gases. During our incident, and faced with an eight-story building, fire showing from the top floor and a report of people trapped, I decided to try a new approach. I only had a non specific report of people trapped. The basis for this report was not provided, so I had no way to evaluate its validity. Of course given that it was 2200 hours in a building with hundreds of units, I had to assume that there was someone in that building somewhere. Having been on fires in these buildings before, I know that it is hours after the fire is out before we can conclusively confirm that all persons are out of the building. With that many individual dwellings units, the search process is slow.
Current firefighting paradigms suggest the demarcation of “attack,” “vent,” and evacuation stairways. But I find this thought process to be flawed. I believe that sufficient social science research, specifically fire behavior research, will say that when faced with an emergent situation, people will leave the building using the same pathways they do on a daily basis. Perhaps sufficient education about the dangers of using an elevator in a fire will prevent too many people from doing that. But you are still faced with people already operating in an emergent situation under their unpracticed “plan B.” Even if we could tell them which stairwell was the evacuation stairwell, would they understand and would they comply?
The more realistic scenario is that each of the stairs will have people in them of varying age, health and mental status, and in various states of need. While I buy the notion that most of the evacuees can self-rescue or be rescued with the help of their neighbors, I think it is imperative that the fire department ensure that stairs are clear of smoke to the greatest extent possible. This is how we do the greatest good for the greatest number.
With the exception of the fire apartment and the exposure apartments, what is the problem? In the exposure apartments, those immediately adjacent to the fire apartment in all directions, people are in danger of significant fire spread. For the rest of the building, they are in danger of significant smoke spread. I know for a fact that:
1. We cannot get to all the occupants in a timely fashion
2. They cannot safely self-evacuate through multiple floors of dense smoke.
Given all those factors, the incident commander is faced with two basic strategic approaches:
1. Go after the fire as quickly as possible with hose line supported searches of the exposure units and then manage smoke spread.
2. Confine the fire and smoke spread to the apartment/area of origin, provide safe evacuation routes for the self-evacuating, and then go after the fire as quickly as possible with hose line supported searches of the exposure units.
The difference in strategic approaches is significant, even more so if the initial alarm responding to the fire does not have sufficient staffing or a sufficient skill set to accomplish both smoke management and fire attack simultaneously.
I think that both approaches are valid and the one you choose has to be based on the assessment of real people looking at a real problem in real time. Theory begins to break down as people begin to engage reality.
In my scenario, there was no reporting apartment for the people trapped, there was no indication that a caller was still on the line; there was simply general information that people might be trapped. This information is critical, but the nature of its criticality is based on the methods and processes that generated that information.What the caller actually says is typically not in the knowledge domain of the incident commander.
My answer to the problem of an eight-story building with fire showing from the eighth floor was to use the first two engine companies to stretch a line to the fire floor; they were staffed heavily and they operated under a Division 8 Supervisor. Once assigned, it was up to Division 8 to decide if he had sufficient resources in material and personnel to accomplish all the tasks under his supervision. In a more controversial move, I used the first due truck company to establish a ventilation group, with the expressed goal of limiting smoke spread as discussed earlier.
The lessons
The fire was relatively small and handled quickly by the first line. The smoke was limited to the fire floor. There was little or no wind that night. We got lucky in many respects because there was confusion about the ventilation plan such that there was no support of the engine companies on the fire floor and no effective management of the smoke. Remembering that the trade off I was willing to make for truck support on the fire floor was effective smoke management.
My most glaring lesson was that I changed “the way we do things” on the fly. The standard mindset of a first due ladder with a report of persons trapped is to get to the fire apartment as quickly as possible. Without having discussed my theory or having trained with crews on it, they found what I was saying counterintuitive. Because they could not turn the message into effective action, that entire crew was lost.
Being able to quickly develop common frames of references and common operational pictures is critical to effective fireground operations. The standard fireground is not the place to try the new ideas for the first time.
Another lesson learned is that we all tend to make decisions with an expectation bias. In other words, the incident commander has a picture in his head of what the future state of operations will look like after the orders he gives are implemented. For example, after I gave the order to pressurize all the stairs, I had a vision of a truck company setting PPV at the bottom of each stair and firing them up. This is not what happened. However, my mind was made up that I had given this order and that my picture of what the world would look like would turn out to be true.
I am not certain if the failure was in the change in tactics or in the communication process. But what is certain is that my picture of how events were unfolding was not how they actually were. The only fix to that particular problem is the improvement of both the peer to peer and hierarchical communication pathways on firegrounds.
So we end a “lessons learned” session with a discussion of communications — but that is only because once again the failure to effectively communicate, as defined by the development of a common operational picture, was again a problem.
The editorial
As I final note, I would like to point out the need for more evidence-based training and practice in the fire service. For too long we have relied on what we have always done as the primary metric for judging success. As someone I know said recently when discussing aversion to an impending change, "…they don’t like it because it ain’t a leather helmet.” We continue to be stuck in the leather helmet school. But for me, modern hazards and modern construction both encourage us to push beyond tradition. Of course we can handle most of our fires and other emergencies with the leather helmet approach, but not all of them. If the research is being done, and it is, then the fire service should take that work and fold it into how they frame their respective approaches to fighting fires.
Related Resource: Fire.Gov: Positive Pressure Ventilation |
