Coffee Break Training: Building Construction: Part 2: Fire Investigations: Building Loads and Fire Spread [open pdf - 166KB]
"Building loads of concern to investigators include dead load--the weight of the building and any permanently attached equipment, live load--which is produced by use and occupancy of the building, and impact load--which could be created by an investigator jumping onto a floor. A load-bearing wall is a wall that supports a vertical load, such as a floor or roof, in addition to its own weight. Failure in walls and other components can depend upon the composition material or materials. Combustible construction will burn, reducing mass and load-carrying capacity. Steel begins to weaken at about 600 °F (316 °C). It is estimated that at approximately 1,100 °F (593 °C), steel will lose about 60 percent of its load-carrying ability. Concrete is noncombustible and typically is strong in compression but weak in tension. It may be plain or reinforced. Plain walls include unreinforced brick where the effects of fire and fire suppression may cause failures. Reinforced walls can also fail, especially if the reinforcing elements become exposed to the effects of fire."
Coffee Break Training - Fire Investigation Series No. FI-2010-2
United States Fire Administration: http://www.usfa.fema.gov/