By Charles Bailey
The modern firefighting environment is defined by structures, interior configurations, and fuel packages that are capable of producing extreme changes in fire behavior in short periods of time. This situation is radically different from legacy structures and has been driven primarily by changes in materials, both structural and furnishing.
When rapid changes in fire behavior will occur is variable and unpredictable. To that end the fire service has no choice but to change its operational paradigm. Our ability to predict rapid changes in fire behavior rely on our knowledge of the current state of fire growth, interior flow paths, and our ability to sense changes in the environment all of which are inaccessible to us during initial operations.
Because firefighters cannot possibly make rational risk decisions (What is likely to happen?) during structural fire suppression operations unless they are afforded full access to all pertinent variables, the modern firefighter must rather engage in assessments of uncertainty (What could possibly happen?).
What has not changed is that life safety remains the foremost incident priority. We still exist primarily to save lives and property from the ravages of fire.
What has changed is that fire in modern environments grows so quickly, produces so much heat, and requires so much oxygen, that tactically the best way to have a positive impact on life safety is to apply an overwhelming cooling streams to interior compartments as quickly as possible from the most advantageous points possible. This must be done while limiting, to the extent possible, any introduction of new oxygen and/or the creation of any possible flow paths until such time as the interior environments are being effectively cooled by water streams.
The under-ventilated fires typical of the modern fire environment are capable of generating carbon monoxide at 50,000 ppm; the IDLH for carbon monoxide is 1,500 ppm.
Further an under-ventilated fire is characterized by the presence of dense, turbulent smoke, by definition sufficient heat and fuel are present to support combustion, but without sufficient oxygen there is no flaming combustion; this is the same oxygen that possible victims require to breathe. Finally, the heat present in a fire dying down from a lack of oxygen is present in sufficient quantities to render unprotected human life impossible.
The best possible protection for trapped occupants is to be isolated from the seat of the fire. It is nearly impossible for the fire department to arrive, establish water supplies, stretch lines, get prepared at the threshold, stretch inside, search, find and remove victims before they are adversely affected by carbon monoxide. Victims isolated by fire are as safe as they are going to get while the structure or its contents are burning.
Any actions conducted by the fire department must consider what happens to these relative safe havens as:
- The fire continues to grow (and the danger continues to grow)
- The fire department moves through interior spaces, opening doors, creating flow paths and otherwise interfering with interior conditions
People trapped by fire are trapped by fire and it stands to reason that first, most appropriate, action is to suppress the fire.
There are certainly occasions where victims are visibly in need of rescue on fire department arrival. These victims all deserve the immediate attention of all available fire department resources. In such cases the first arriving officer must make the critical decision of whether he or she can effect the rescue immediately without first suppressing the fire or whether both tasks can be accomplished simultaneously.
There may also be cases where a report exists of a trapped occupant, even though that occupant is not visible. In this case the fire officer must engage in an effort to locate the missing person but only to the extent that he or she can reasonable expect to be able to isolate the search from the main body of the fire.
Interior searches are proper and are necessary but they are not the same as the rescue of visible victims. Interior searches must be conducted at every structure fire but always subsequent to the application of water streams.
All fire ground operations must be initially directed, conducted and conceived of as a water supply and delivery operation for the first due suppression line with all other functions, save for the obvious rescue, beings subordinate functions. No additional effort can be launched until the first line is in place, charged, and operating.
Finally, the firefighter must go to work believing without fail that any platform he or she operates on, near, under, or above that has been subjected to fire is inherently unstable and likely to collapse. It is neither wise nor necessary to operate on, near, under, or above a platform that is likely to collapse.
To that end fires must always be suppressed from the lowest level first and operations above that level should come only after there has been sufficient time for rational analysis of the prevailing conditions.
The basic need for fire suppression has not changed, and while the equipment available to firefighters has improved dramatically over the past few decades, concurrent changes in the nature of the fire environment have changed more dramatically.
It is no longer prudent for the educated fire officer who is focused on victim and crew safety to continue to engage structure fires as if nothing has changed. It is critically important for the fire department to realize that successful outcomes are more likely when crews simply do whatever they can to put the fire out quickly.