Firefighter Safety Report: Truss System Failures
NIOSH | John Howard M.D.
At least three scenarios can occur in which fire fighters suffer fatalities and injuries while operating at fires involving truss roof and floor systems [Dunn 1992]:
1. While fire fighters are operating above a burning roof or floor truss , they may fall into a fire as the sheathing or the truss system collapses below them.
2. While fire fighters are operating below the roof or floor inside a building with burning truss floor or roof structures , the trusses may collapse onto them.
3. While fire fighters are operating outside a building with burning trusses , the floor or roof trusses may collapse and cause a secondary wall collapse.
The following case reports describe incidents involving fire fighter injuries and deaths due to fires involving truss system failures. The incidents were investigated through the NIOSH Fire Fighter Fatality Investigation and Prevention Program.
On March 8, 1998, one male career fire fighter, a captain (victim), died when the wooden-bowstring trussed roof of a building collapsed and blocked his exit route. The first company on the scene reported light smoke showing from a one-story commercial building.
While fire companies waited for the security doors to be opened, fire conditions changed dramatically on the roof. Heavy fire was coming from the ventilation holes opened by the ventilation crew. When the doors were opened, the fire fighters encountered heavy smoke with near-zero visibility approximately 15 feet inside the door.
The engine crews advanced until deteriorating conditions forced them to withdraw. During this time, the victim became separated from his crew and did not exit from the building. Approximately 20 minutes after the engine crews entered the building, the roof partially collapsed, blocking the front entry and hampering rescue operations.
The victim was later located by the Rapid Intervention Team, and cardiopulmonary resuscitation was performed immediately and enroute to the hospital, where the victim was pronounced dead [NIOSH 1998a].