Firefighter Safety Report: Truss System Failures
NIOSH | John Howard M.D.
• Consider using a thermal imaging camera as part of the size-up operation to aid in locating fires in concealed spaces.
• Account for the type of building construction (i.e., presence of truss construction) when determining (1) the number of fire fighters available, (2) the amount of apparatus and equipment needed to control the blaze, (3) the most effective point of fire extinguishment attack, (4) the most effective method of venting heat and smoke, and (5) whether the attack should be offensive or defensive.
• Continually conduct size-up from the time the alarm is received until the fire is under control [Brunacini 1985]. Analyze risk versus gain continuously during incident operations [Dunn 1998].
• Evaluate the type of structure (residential, commercial, etc), time of day, occupancy, contents of the structure, hazards, exposures, etc.
• Try to find out the type of construction, age of the building, and whether modifications or additions have been completed to help assess structural stability [Dunn 1996].
• Pay close attention to the conditions outside the structure, monitor the roof, and also check on interior conditions [Dunn 1996; NIOSH 1999].
• Plan for search and rescue operations before an emergency occurs in case a fire fighter becomes trapped.
• Immediately notify the Rapid Intervention Team when truss construction is identified.
• Ensure that fire fighters performing fire-fighting operations under or above trusses are evacuated as soon as it is determined that the trusses are exposed to fire (not according to a time limit).
• Establish a collapse zone when operating outside a burning building, since truss roof collapses can push out on the walls, causing a secondary collapse of the exterior walls.
• The collapse zone should be equal to the height of the building plus allowance for scattering debris [Brannigan 1999; Klaene and Sanders 2000; NIOSH 1999], usually at least 1½ times the height of the building.
• Use defensive overhauling procedures after fire extinguishment in a building containing truss construction. Use outside master streams to soak the smoldering truss building and pre vent rekindling [Brannigan 1999; Klaene and Sanders 2000].
• Consider becoming involved in the building code development and enforcement process.
• For more information about preventing fire fighter injuries and deaths from structural collapse, see NIOSH 1999 and relevant research on new structural collapse prediction technologies: www.usfa.fema.gov/inside-usfa/research/safety/nist1.shtm [USFA 2004a].