DUNN Flashcards
What is the weak link in the construction of fire resistive high rise buildings
Floors
Spray fire retardant material needs 3 things to be effective
Adhesion
Consistency
Thickness
Factors that will increase the number of burning building collapses
Age (buildings have a lifespan of 75-100 years)
Abandonment
Lightweight construction material
Faulty renovations
Which part if the building is more likely to collapse and kill firefighters
Floors
Order according to Dunn Floors Roofs Walls Ceilings
The 7 primary structural members
Bearing walls Columns Girders Headers Hip rafters Ridge poles Trimmer floor beams
Heat activated fire damper may stop the flame spread but does not
Stop the spread of smoke throughout the systems air ducts
Experience has shown us that firefighters operating hose lines cannot extinguish fires in floor areas over
5000 SQ FT
Most common type of masonry wall failure
Straight out at a 90 degree angle
The most dangerous canopy is
Metal or wood shed suspended over a truck loading area, covered with tarpaper and thus extremely flammable
What is more of a collapse danger? A canopy or a marquee
Canopy
The most dangerous time for floor collapse occurs in what stage of the fire
Decay stage
After the fire has been extinguished
When should you increase the collapse zone from the height of the building to 1 1/2 to 2 times the height of the building
Truss roof that may trigger the wall collapse
Explosion
Ordered by the IC
The most dangerous area outside a burning building
Sidewalk in front of the building and it is even more dangerous if the building has a parapet wall
The most dangerous parapet wall is
Front wall of a one story structure above several large display window
The most deadly type of floor collapse
Multilevel floor collapse
A multi level floor collapse most often happens in buildings that have
Columns and girders supporting the floors. A building with a frontage of 25 feet or more usually has columns and girders
What is the safest sloping roof to walk on
Rafter constructed roof
What is the largest unsupported roof deck
Truss roof
Next largest is the plank and beam roof
The most common timber truss roof
Bowstring truss
The most unstable parts of a house of worship
The tower and steeple
Lightweight wood truss construction can fail in
5-10 minutes
The failure temperature of steel
1,000 - 1,100 degrees
The fire service considers 1,100 to be the failure temperature
The least effective way of protecting steel from fire
Spray on fire retarding material - SFRM
Also the most popular but least effective
50 foot long beam heated uniformly over its length will increase
3 feet 9 inches
Because of severe hazards associated with truss construction New York has a law requiring
2 vertical lines to identify truss construction
The rate of fire spread in a buildings concealed spaces that utilize parallel chord lightweight truss will be
100% faster than in conventional solid wood construction
The most dangerous ceiling is a
Suspended ceiling
After a suspended ceiling collapse there is always
A rapid fire increase
The ceiling collapse killing most NYC Firefighters is the
Wood grid suspended ceiling
The most important 1st step to rescue trapped members under a collapsed ceiling during a store fire is to
Sweep the collapse area above the ceiling with a hose line and knock down the flames
In most multi story buildings the stairway is the safest area in the wooden interior of the building and logically the best avenue for the initial fire attack
True
The preferred stair in modern building construction is the
U-return
Which type of stair will not fail if the floor collapses
U-return
The most serious injury to members on steel framed u-return stairs occur when the
Intermediate stair landing collapses
The most frequent cause of collapse in the steel u-return stair is the
Stone stair tread or step
What is the safest type of fire escape
Exterior screened stairways
The best way to remove numerous people from a fire escape is
Through the designated horizontal exit and into the adjoining apartment window or door
The most dangerous type of wood frame building collapse
The inward-outward collapse
It may involve the collapse of 2, 3 or 4 walls simultaneously. Only firefighters in the corner safe zones will survive the collapse. The corner safe areas are the 4 flanking zones around a burning wood frame building
The 4 most widely used methods of wood framed construction
Braced frame
Ballon
Platform
Lightweight wood frame
Out of the 4 most widely used methods of wood frame construction which one is the most dangerous to firefighters
Braced frame
What is the danger to firefighters during the early stages of fire in a building built using lightweight wood construction
Early floor and roof collapse of truss floors and roofs
Wooden buildings located on a corner plot or standing alone are more susceptible to
Global collapse during fires than wood buildings in the center of a row. When a serious fire burns out the entire 1st floor of a 3 story wood building there is a danger of global collapse
Concrete reaches its maximum strength after
27 days
After how many hours does concrete floors have enough strength to enable the wood formwork below be removed and reconstructed above
48 hours
Shanties are required to be non combustible and at least______
Feet from the building under construction and they cannot be grouped together
30 feet
A party wall where roof beams from both sections are supported by the wall is not a true fire division. Collapse of the roof on one side could cause the party wall to collapse on the other side
( True or False)
True
Applications of sprayed on fire retardant material (SFRM)over primer painted steel reduce its effectiveness by
1/3 to 1/2
During what stage or stages of fire is the buildings structural framework most often affected by a fire
2nd stage (fully developed stage) 3rd stage (decay stage)
The most important strategy and tactical consideration at a fire is
Water supply and pressure
What is the correct collapse danger of private dwellings
Collapse of 1st floor
In a finished basement with a ceiling the ceiling barrier can give floor supports_____ or more minutes of fire protection
20 or more minutes
Can SA battalion chiefs due theater inspections
Yes
Hierarchy Of Collapse
1) Bearing Wall (most serious)
2) Column
3) Girder
4) Beams (floor or roof)
5) Deck (least serious)
2 Types of ceilings
Directly affixed
Suspended
3 Types of suspended ceilings
Wood Grid
Metal Grid
Lightweight Grid
