12- Building Construction- Special Structures and Design Features Flashcards
MODEL BUILDING CODES define a high-rise building as:
Being more than 75 feet in height.
The FIRE PROTECTION definition of a high-rise building is:
Any building with occupied stories beyond the effective reach of fire equipment located at the street level.
Two developments that made high-rise buildings possible and practical at the end of the 19th century were:
-The use of steel frame construction
-Elevators
High-rise buildings use ___ ____ construction. Usually a combination of reinforced concrete with a protected steel frame. Tall buildings usually have a reinforced concrete core housing the elevator shafts with the remainder of the frame being steel.
Fire-Resistive
Typically, model building codes require _ or _ hour fire resistance for the STRUCTURAL FRAME of a high-rise building, depending on the number of stories and occupancy, and _ hour fire resistance for FLOOR CONSTRUCTION.
structural frame = 2 or 3 hour
floors = 2 hour
In early high-rise buildings, fire protection was usually provided only by ____ _____.
Standpipe Systems
The _____ risers and hose valves are located within the stairwells to provide a protected location from which to advance a hoselien.
Standpipe
One unavoidable problem with standpipe systems is:
The variation of pressure in tandem with building heights (hydrostatic pressure).
In regards to hydrostatic pressure issues in standpipe systems, NFPA 14 mandates the use of ____ ____ _____ according to the jurisdiction’s needs.
Pressure Reducing Valves
_____ and _____ systems are typically supplied from the same vertical riser. These systems will be supplied by one or more fire pumps located in the basement of the building.
Sprinkler and Standpipe
In high rise buildings, vertical extension of fire and smoke can occur through floor penetrations, such as elevator shafts, stairwells, and utility shafts. Consequently, building codes require that vertical shafts be ______.
Enclosed
The elevator code requires a ____ ____ where the elevator hoistway or elevator room is protected by automatic sprinklers. This arrangement will shut down the power to the elevator before a sprinkler discharges water on the elevator equipment.
Shunt Trip
Only consider using an elevator during emergency operations if the fire is above the ___ floor.
Fifth
Codes contain mandatory provisions for the recall (Phase __ Operation) of all passenger elevators with vertical travel greater than 25 feet in the event of fire.
I
Phase __ Operation automatically stops all the cars that serve the fire floor if they are moving away from their terminal floor (the lobby). It also causes the cars to return nonstop to the lobby, or other designated level if the alarm originated from the lobby.
I
*Does not apply to freight elevators
During Phase I Operation, the elevator car’s ____ ____ and ____ ____ buttons are rendered inoperative so that car occupants who may be unaware of the fire or emergency cannot stop the car anywhere but at the terminal floor.
Emergency Stop and Floor Selection
Phase __ Operation is designed to override the recall feature to permit firefighters to use the elevators after they arrive on the scene.
II
Typically to activate Phase __ Operation, a firefighter must insert a key into a three-position switch within a car to place that particular car in “fire service.”
II
During Phase II Operation, an elevator becomes essentially a ____ _____ elevator. The floor-select buttons within the car remain operable but the floor-call buttons on the individual floors are inoperable. The elevator doors do not open automatically and the operator must push the “Door Open” button in the car.
Manually Operated
The ____ ____ ____, which prevents the doors from closing if there is a person or smoke in the doorway, is disabled during Phase II Operations to allow the doors to be closed ad the car moved if it inadvertently stops at a smoke-filled floor.
Electric Eye Safety
Underground buildings may have occupancy areas __ feet or more lower than their primary exit.
30
Probably the greatest single challenge in controlling fires in underground buildings comes from the difficulty in:
Venting heat and smoke
The maximum available fire-resistant protection is typically __ hours; therefore, fire exceeding this time are a serious threat.
4
Air-Inflated or Air-Supported structures have several limitations including:
-Limited to one story in height
-Vulnerable to the forces of high winds
-The membrane used may be a limited-combustible or noncombustible material (if limited-combustible, it is required to have a LOW flame spread and LOW smoke propagation)
-Can’t be used where fire-rated construction is required
____ _____ structures feature a rigid frame with a tensioned membrane covering, usually with internal columns.
Frame Membrane
Building codes require that mall walkways be a minimum of __ feet wide. This space permits pedestrian travel and also the use of open storefronts.
20
While some shopping malls may be built of fire-resistive construction, many are noncombustible (Type __) or wood (Type __) construction. In recent years, major developers of covered malls have preferred unprotected noncombustible (Type __) construction.
Type II or Type V
Type II-a
Codes require individual stores within a shopping mall to have __ hour fire-resistive separation from each other, but they do not require that individual storefronts are separated from the mall itself.
One
Functionally, an ____ is a large vertical opening extending through two or more floors of a building that is not used for building services such as enclosed stairs, elevators, or building utilities.
Atrium
Building codes have a basic requirement that an atrium be enclosed with 1-hour fire-rated construction or a combination of ____ and ____ _____.
Glass and Automatic Sprinklers
An _____ can be defined as an event that produces a rapid release of energy.
Explosion
The sudden release of energy from an explosion produces outward pressures, often referred to as ____ ____.
Blast Waves
What distinguishes explosions from other occurrences such as or ordinary combustion is:
The speed with which the process occurs.
The typical smoke barrier consists of a minimum __ hour fire-rated enclosure.
One
Warehouses may have multiple rows of racks wider than __ feet or with aisles narrower than __ feet.
Rows wider than 12 feet
Aisles narrower than 3.5 feet
