Chp. 4 Building Systems Flashcards
What roles do stairs provide in a building system?
- enable access to multiple levels of a structure
- serve as a basic component of building egress during
an emergency.
Convenience stairs
- not part of the means of egress
- usually open and connect only two levels per code
limitations.
Six common types of stairs:
- straight run
- return
- scissor
- circular
- folding
- spiral
Buildings that often include scissor stairs:
- airport terminals
- convention centers
- malls
- cinema complexes
The modern design arrangement for scissor stairs allows for ______________ at each floor landing, which provides additional exit capacity. Older designs restrict egress from the stairway into one corridor on even numbered floors and into opposite corridors on odd numbered floors.
- ingress and egress
Circular stairs serve only ________. The minimum width of the run is usually _______.
- two levels
- 10 inches
Firefighters should be aware that springs in ___________ lose tension rapidly when exposed to heat, and the stair assembly may swing down into the structure during a fire, providing a vertical path for fire and smoke spread.
folding stairs
Both folding stairs and fixed ladders may have _________ lower than the weight of a firefighter wearing full PPE. Many departments recommend against using these stairs for firefighting purposes.
weight limitations
Measures indicated in building codes to protect stair enclosures include:
- limited penetrations for light, fire protection, and
environmental control - required self or automatic closing fire rated doors
- separation from rest of building
- stairway vestibules
Building codes have traditionally required a minimum of one smoke proof stair enclosure for stairs serving buildings ____________. More recently, codes also require protection for stairs serving floor levels more than ________ the level of exit discharge.
- five stories or higher
- 30 feet below
Typically located on the exterior perimeter of the building and are entered through ventilated vestibules or open exterior balconies .
smoke proof stair enclosures
A correctly operating system should allow firefighters to begin suppression operations concurrently with occupant egress. In high rise structures, codes require dedicated, ________________ designed solely to provide firefighters a safe route to access and attack a fire.
pressurized stairways
Protect the stairway enclosure and provide a means of smoke ventilation before smoke enters the stair enclosure. Accessed through a vestibule or an exterior balcony.
passive smoke proof enclosures
Building codes typically allow the use of open stairs in buildings only when they connect no more than __________ above the basement level.
two adjacent floors
Conveyor systems often penetrate fire barriers , and are protected by features such as:
- fire doors
- shutters
- water spray fixed fire suppression systems
Material conveyors are typically found in:
- manufacturing or storage occupancies
- airport baggage handling facilities
The driving machinery of a escalator is located where?
under an access panel at the upper landing
Escalator speeds are standardized at __________. Older escalators usually operate at speeds of either _________.
- 100 feet per minute
- 90 or 120 feet per minute
How deep is the draft stop with automatic sprinklers on all sides outside of it around the vertical opening of an escalator ?
- 18 inches
An elevator may be used during emergency response so long as it meets the necessary qualifications. Before such use, firefighters should ____________ and open the door from a floor level above the recalled elevator to check _______________.
- recall the elevator to the lobby
- the shaft for smoke infiltration
Elevators can be classified according to their use:
- passenger elevators
- freight elevators
- service elevators
Two most common types of power used in elevators are :
- hydraulic
- electric
Operates via fluid forced under pressure into a cylinder containing a piston or ram. Pumping in fluid raises the ram, moving car upward, and draining fluid allows car to lower through gravity. Does not have brakes, has height limitations.
hydraulic elevators
Electric elevators use a ______________.
hoisting cable and a drum
Four common style electric elevators are:
- drum elevators
- traction elevators
- machine room-less elevators (MRL)
- dumbwaiters (cargo)
Obsolete and found only in very old structures or in use as freight elevators, has height limitations.
Drum elevators
Most common type of elevator in buildings over six stories, fast with no height limitations.
Traction elevators
Drive motors may be either __________________ types.
- direct current (DC) or alternating current (AC)
Brakes on traction elevators with ____ motors aid directly in stopping the car at the correct floor, but on elevators with ______ motors, the brakes do not play in any part in actually stopping the car. The motor stops the car and then the brakes are applied to hold the car in place.
- AC
- DC
Passenger safety devices found on elevators may include:
- terminal device (terminates power)
- buffers (shock absorbers that only stop a car traveling
at its normal rate of speed) - speed reducing switch (speed governor, can trip
overspeed switch and apply car safeties) - overspeed switch (activated if speed reducing switch
fails) - car safeties (tapered pair of steel jaws designed to stop
a free falling car)
Elevator hoist way enclosures usually are required to be a fire rated assembly with a _______ rating, depending on the height of the building.
1 OR 2 hour rating
May act as a vertical chimney to spread fire and smoke throughout a building
hoist ways
