Recently, we discussed apparatus positioning for truck companies at the scene of a working fire, and we approached this topic with considerations towards operating in an offensive mode; that is, crews were going to be assigned specific areas of the structure and perform assigned tasks with the engine companies working inside to find the seat of the fire. This month, we take an alternative view and discuss some of the same topics taking into consideration that operations will be strictly defensive, or from the exterior of the structure. While many people feel that this is an overall safer approach to fighting the fire, there have been many instances where operating in such a manner has resulted in a significant line-of-duty injury or death. Our discussion this month will provide some points of consideration to keep you and your crew members safely protected on the fire scene.
Much to the distain of many firefighters, many times we find ourselves outside the confines of the structure attempting to extinguish the fire raging within. It is in our nature to be aggressive and efficient; however, this is a trait that can land us in significant danger, sometimes with catastrophic results (see Photo 1). Progressive officers and incident commanders must evaluate the “bigger picture,” and have the wisdom to make the defensive call when the need arises. In my years as a fire officer and an incident commander (IC), there are a few “clues” that almost always scream Defensive:
Buildings that have burned before: For some reason, somebody, somewhere, wanted that building to burn. Usually when responding back the second (or third) time, the fire is larger and much more developed during the previous alarm.
Buildings under construction: Structures that are still in the early phases of construction are nothing more than stacked lumberyards, and in today’s construction practices, are filled with larger open void spaces and engineered structural components (i.e., lightweight components). Open void spaces will result in rapid ventilation and fire spread, making the defensive posture upon arrival the most prudent decision (see Photo 2).
Buildings that are abandoned/under demolition: While this may seem like a common sense decision, many times firefighters are injured or killed risking their lives for no sustainable life hazard or property (see Photo 3). The building is coming down, no matter how aggressive the attack.
Adding to the list of clues, there are some significant construction issues that should cause concern in the mind of the IC:
Cornices:These ornate decorative moldings originally were designed to throw rainwater away from the front wall of a structure, but they also serve as a significant collapse hazard. Whether they are eccentrically secured to the front wall, or designed to be freestanding, they can come crashing down with little or no warning (see Photo 4).
Parapet Walls: A freestanding extension of the front wall of a building, they can also have coping stones around the top edge of the wall, compounding the total weight of the assembly. Connections made from the parapet to the structure are limited, and usually are exposed to the elements, resulting in deterioration of the connections. Furthermore, heavy fire will begin to distort the lintel the parapet rests on; the twisting of the steel span will result in the assembly failing as an entire unit.
Tension Rods: These rods can be cable or threaded materials, and are utilized to hold parallel masonry walls together. At each end of the rod, there is a protrusion of the rod through the wall where a connection is made to a spreader plate, which is used to distribute the load throughout the wall. Many times the original plans for the structure included tension rods in the construction process; in this case, the rods will look symmetrical in nature, orderly and aligned throughout the structure. An alarm should go off when these rods are located throughout the structure in various sporadic locations (see Photo 5). Furthermore, these assemblies have been proven to fail at around 800°F, leading to total wall assembly failure.