MORE REASONS THAT COLLAPSE ON THE FIREGROUND SHOULD NOT BE A SURPRISE
BY TOM BRENNAN
Let`s talk about incidents that would forecast to forces within the building a “Mayday” call indicating that collapse is imminent.
On the side: Mayday–the signal/message that demands that all interior forces cut and run–is just that. It is an order to forces to get out of the building any way possible–as opposed to an orderly withdrawal because the strategy must shift to defensive. I pause here to mention this because the difference between the two often is confused and causes serious trauma on the fireground. Many of us have signals that tell us to get out of the structure–sometimes it`s a horn or siren sounded on the fireground, and other times it`s tones generated from central communications to the portable radios at the scene.
The safety point here is that many have this romantic love affair with “pulling the plug” for situations that indicate an orderly withdrawal. Without collapse as an imminent factor, handlines must account for those they are protecting (other areas of the fire floor, particularly those on the floors above the firefight) before they back out. I can vividly recall many instances in which I was directly and indirectly involved in such situations. Near panic takes over the command function: Mayday signals are used, and all the handlines are dropped instantly. The members in the position mentioned above are left to shift for themselves. Fire rapidly cuts off those behind it and takes possession, unchecked, of the protected interior stair. Fortunately, because of the cool heads inside the building and rapid understanding of those outside, portable ladders and aerials were able to be positioned and repositioned for escape–at least in my case. But, there were other cases where more unfortunate results occurred–you really never hear about those!
“MAYDAY” INDICATORS OF COLLAPSE
Perhaps the most dangerous sign–and the easiest to recognize–is the partial collapse of a portion of the structure that is part of the structural integrity of the whole. A parapet lets go into the street for no apparent reason (or was there a reason?). An unseen section of a side enclosure or rear wall fails. Mayday!
The only comment on partial collapse is that it must be detected. A myth is that collapse makes a lot of noise. This is not true. There is very little noise; and if the area is interior and remote from fire forces and their immediate focus, the event may have no mental consequence or not be detected at all until it is too late. Our people must be made aware that they should question unknown noises or concussions and should report and investigate them.
Taking the danger signs in order of importance (severity), the next sign would be a crack in structure. In masonry construction, the crack could be horizontal, vertical, diagonal, or any combination of the three. I know that many of you are thinking, “Come on, all masonry has cracks. I`ve had cracks in my cellar floors and walls for years.” What we are talking about here is a moving crack that appears longer or wider the next time you look at it. The movement tells you one thing: The building is moving. Get out! Mayday!
The frame building does not display cracks until it begins to bulge or lean. The most common crack usually is horizontal and at the point where ceiling plates and studs of the next floor are joined. Another Mayday.
If cracks are not easily seen, it doesn`t mean they are not there. Watch the smoke, you on the outside of the building. Is it coming through the masonry facade? Smoke is not supposed to be able to issue through a concrete or block building. Even to the least sophisticated, it means that there is an opening from inside the structure to the outside where there was none before.
The next sign is bulges in walls. Why would a wall bulge and what does it mean? Something is pushing it from inside. In masonry bearing walls, it usually means that steel beams are moving. Steel is elastic and moves eight to nine inches in 100 feet when heated to relatively low levels of 700°F. The important consideration when a wall is bulging is that the wall no longer has any strength. It is like the support factor of spaghetti–uncooked some, cooked none. Mayday!
Distortion is another factor. It can be detected easily from outside and subtly from inside. Distortion is indicated when the building openings seem to be suddenly out of square–the window assemblies and doors no longer are configured with the shapes of the openings. The building has moved or is continuing to move. Get out!
Inside signs of distortion show themselves during overhaul: Doors do not shut in their frames or, for some reason, a door opens in the room in which you are working. This time it may not mean “get out,” but it should be reported, and other areas of the interior should be checked.
Another Mayday situation is when occupants (them or us) are inside an exposure that is within the collapse zone of a building whose integrity is in question. These structures are doomed when one building falls on another. A close friend was killed years ago when a portion of the four-story original fire building collapsed on the roof of the one-story extension. Any building within the horizontal distance of the height of the one planned for collapse is in danger and must be vacated immediately–just as the fire building. Buildings are not strong enough to take the hit of a falling building.
Well, these are the major signs that signify the need for immediate action and evacuation. There are many others that, although not as urgent in and of themselves, must be recognized, communicated, and recorded. Eventually, the growing list of these indicators will signal that interior operations are no longer worth the risk, and strategy will change–collapse will be planned for and not come as a surprise. We`ll hit these basics next time. n
TOM BRENNAN is chief of the Waterbury (CT) Fire Department and a technical editor of Fire Engineering. He spent more than 20 years in some of the world`s busiest ladder companies in the City of New York (NY) Fire Department.
