Preparing for collapse

Whether they were on the roof or under it, in the collapse zone, four firefighters lost their lives in a restaurant fire that spread to an adjoining hotel in Houston Texas. The after-action report, though not out yet, will share valuable information about what went wrong. Building collapses hurt or kill firefighters and civilians alike. The point is that buildings that are prone to collapse, simply because of construction, should be known before the fire ever occurs. Buildings with a bowstring truss roof have been known to collapse quickly, when fire impinges on the roof members. There are buildings on Jefferson Davis Highway with this roof construction, even though some have been concealed by reconstruction. Roofs with steel bar joist construction have collapsed, whether due to fire impingement, heavy stock in the attic area or a combination of both.

One would think that new construction would be less likely to collapse, but this is not true. Lightweight construction has become the norm, reducing costs for the consumer. Truss construction with metal gang plates is the norm, rather than the exception. When fire impinges on trusses, they burn through or weaken. The loss of two or three trusses could cause a collapse of the entire roof system. The philosophy of departments performing roof operations varies from one department to the next. Lightweight construction should serve as a deterrent to putting firefighters on the roof, when a building is involved in fire.

Though there can be older construction in our counties, the cities are most prone to this type of construction. In some cases, the roof construction may be heavy timber. Collapse is possible, but not likely in the beginning stages. As buildings begin to age, the wall systems begin to weaken. To draw them back together, steel tie rods are used to hold walls together. The problem occurs when flames impinge on these rods. Wall collapse can occur a distance out of 2-3 times the wall height. Being able to determine buildings with these rods should affect apparatus placement and be cause for a high index of suspicion.

Concerning buildings on fire, collapse should be expected when:

  • The fire has impinged on roof members for a period of time
  • Smoke is issuing from wall cracks
  • A bowing of floor members is noted
  • More water is going in than coming out
  • Weight has already been added to the roof, such as snow or HVAC units
  • A twisting of steel bar joists is noted

There are many other indications of collapse when a building is on fire.

I am thankful for Chesterfield Fire & EMS’s emphasis on safety. A number of years ago, Chesterfield put a Tactical Safety Officer or TSO on each shift. The TSO’s job, among many things, is to respond to various incidents, performing the work of the Safety Sector in the Incident Command Structure. I had the privilege of serving in this role as an alternate TSO. Firefighter safety must be at the forefront of every firefighter, officer and Incident Commander’s thought process. I have a difficult time accepting the loss of firefighter lives for nothing except attempting to save the life of another. Once all occupants have been accounted for, “every” precaution must be taken to protect the lives of firefighters. No building is worth the life of a firefighter.

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