Firefighter Safety Report: Truss System Failures
NIOSH | John Howard M.D.
On June 15, 2003, a 39-year-old male career lieutenant (Victim 1) died, and another 39-year-old career fire fighter (Victim 2) was fatally injured while trying to exit from a commercial structure following a partial collapse of the building’s flat metal roof, which was supported by lightweight metal trusses (bar joists).
Victim 1, the lieutenant of the first responding engine company, reported light smoke on arrival at a discount store. The flat roof consisted of metal decking covered by wooden fiber insulation and asphalt. A suspended ceiling in the main store area approximately 12 feet high covered the metal roof trusses and obstructed their view from below.
Victim 1 led his crew into the store to search for the fire. After proceeding approximately halfway to the rear of the store, he directed two fire fighters to go outside and bring in a pre-connected hand line. Victim 1 and a lieutenant from the second en gine company proceeded to the rear of the store.
This lieutenant found the fire behind the closed office door and exited to pull a second hand line. Soon afterward, Victim 1 requested a truck company to enter the store and pull ceiling tiles to search for fire extension; a third lieutenant and a fire fighter immediately responded.
The truck company searching for fire extension observed fire in the truss void above the suspended ceiling. The accumulation of smoke and hot gases within the truss void mixed with fresh air as the ceiling was opened and violently ignited. The fire rapidly spread from the rear office area to the main store room through the hidden truss void.
Victim 1 radioed that it was getting too hot and everyone needed to back out. At this point, the roof system at the rear of the store room began to fail, sending debris downward, with several bar joists coming to rest on metal merchandise shelving. Several fire fighters were able to escape by following the hose lines toward the front of the store.
Victim 1 and Victim 2 (the nozzleman from the first responding engine company) became separated from the rest of the fire fighters and were unable to escape. As conditions worsened, the building was evacuated, and a rescue attempt for the two missing fire fighters was initiated.
Fire fighters working at the rear of the building heard a personal alert safety system (PASS) device and quickly entered to investigate. Victim 2 was located in the rear storage room close to the office. A second PASS device was also heard further into the building. Soon after Victim 2 was brought outside, the rear of the building collapsed, preventing further rescue efforts until the fire was brought under control. Victim 1 was located approximately 1½ hours later.
Victim 2 was hospitalized and died the next day [NIOSH 2004].