Collapse 2nd Edition Flashcards
(107 cards)
According to NFPA the leading causes of FF deaths are?
- Stress
- responding/returning from emergencies
- falls
- falling objects
- coming in contact w/ objects
- ff caught/trapped
- burning building collapse
4 factors that will increase burning building collapse?
- age of building
- abandonments
- lightweight construction
- faulty renovations
Buildings have a life expectancy of ?
75 - 100 yrs
older buildings structures of this country will collapse at an increasing rate and kill more ff unless there is a much greater effort in?
preservation, rehabilitation and legal renovation
Abandoned and neglected, unoccupied structures are know as?
Target hazards
* must be targeted by FD for frequent inspections, board-up orders and fire preplanning
What cracks masonry walls?
Freeze-thaw cycle
*wind and rain erode mortar between bricks.
* water seepage into an unheated building s masonry wall will freeze, expand, and crack the bricks
NFPA states unprotected lightweight steel bar joist fail when exposed to fire for?
5 to 10 min
What part of the WTC towers was the first part of the building to collapse according to NIST?
Floors
During a fire a braced-framed building will often collapse?
Inward/outward
A bend twist or curve of a structural element?
Deflection
A facade includes 4 collapse dangers?
Marquee, cornice, canopy, parapet wall
A combination of dead load a live load is?
Gravity load
a gravity-support beam designed to release itself from the masonry wall during collapse?
Fire cut beam
* a beam end that is simply resting on a corbel shel or a girder
The roof a church with a peak is supported by?
side walls
an unsupported lean-to floor collapse can be caused by
A bearing wall failure
Most structural elements are designed with a safety factor of?
2 or more
A bearing wall that supports floors and roofs of 2 buildings?
Party Wall
The danger of a truss only exist when?
under fire conditions
To melt steel what temperature is requried?
2400°
* really reached at a structure fire
2 of the most common structural elements formed by bending steel is?
C-Beam and bar joist truss
the failure temperature of steel is in the range of?
1000° to 1100°
What temperature does a structure fire typically reach?
1700°
Time Temperature curve test states that ?
1000° takes 5 min
1300° takes 10 min
1700° 1 hour
2000° 4 hour
2400° 8 hours
Steel fails at temperatures of 1100° and looses?
40% of its load carrying capacity