Chapter 5 Reading Buildings Flashcards
Define Axial Load
A load that is imposed through the centroid of tanother object
Define Balloon framing
A construction method in which continuous wood studs run from the foundation to the roof, and floors are placed on a shelf-called a ribbon board-that hangs on the interior surface of the studs
In balloon framing what does the floor rest on
ribbon board hanging on the interior surface of the studs
Define beam
A structural element that transfers loads perpendicularly to the imposed load
Define Brittle
Description for a material that will fracture or fail as it is deformed or stressed past its design limits
Define Cantilever Beam
A beam supported at only one end, or a beam that extends well past a support in such a way that the unsupported overhang places the top of th ebeam in tension and the bottom in compression
Define Collapse zone
The area that is exposed to trauma, debris, and /or thrust should a building or part of a building collapse. It is a more specific form of a no-entry zone
Define Column
A structural element that transmits a compressive force axially through its center
Define Compression
A force that causes a material to be crushed or flattened axially through the material
Define Connection
A structural element used to attach other structural elements to one another
Define continuous beam
A beam that is supported in three or more places
Define Curtain wall
A non-loading-bearing wall that supports only itself and is used just to keep weather out
Define Dead Load
The weight of the building itself and anything permanently attached to it
Define Ductile
Description for a material that will bend, deflect, or stretch as a force is resisted, yet retain some strength
Define Eccentric load
A load that is imposed off-center to anther object
Define Emergency abandonment
A strict order for all crews to immediately escape from a building interior or roof, leaving hose lines and tools that can impede rapid retreat behind
Define Engineered wood
A host of products that consist of many pieces of native wood (chips, veneers, and sawdust) glued together to make a sheet, a long beam, or a strong column
Define false work
Temporary shoring, bracing, or formwork, used to support incomplete structural elements during building construction
Define General Collapse
The complete failure of a building to resist gravity
Define Girder
A beam that carries other beams
Define Hybrid building
A building that is a mix of multiple NFPA 220 types or that does not fit into any of the five types
Define a lintel
A beam that spans an opening in a load-bearing masonry wall, such as over a garage door opening (often called a “header” in street slang)
Define Live load
Any force or weight, other than the building itself, that a building must carry or absorb
Define a partial collapse
An event in which the building can accept the failure of a single component and still retain some strength (such as curtain wall collapse)
Define platform framing
A construction method in which a single-story wall is built and the next floor is built on the tops of the wall studs, creating vertical fire-stopping to help minimize fire spread
Define Precautionary Withdrawal
A directive for crews to exit a building interior or roof in an orderly manner, bringing hoses and tools along
Define Raker
A diagonal brace that serves primarily as a column but must absorb some beam forces as well
Define Shear
A force that causes a material to be torn in opposite directions perpendicular or diagonal to the material
Define spalling
The crumbling and loss of a concrete material when exposed to heat
Define spreader
A seemingly decorative star or other metal plate used to distribute force over more bricks or blocks as part of an unseen corrective measure that exists inside a building
Define tension
A force that causes a material to be stretched or pulled apart in line with the material
Define truss
A series of triangles used to from an open-web structural element to act as a beam
Define veneer wall
A decorative wall finish that supports only its own weight
What is the starting point for predicting collapse potential at a structure fire
various methods used to classify a building, building classifications
In building terms stressful elements create….What?
Loads
5 ways loads are delivered
Concentrated, distributed, static, suspended, or impact
What is stress and strain imposed on building materials
Force
What is imposed on building materials
Loads
3 types of forces
compression, tension, shear
What material characteristics affect response to force
Type, shape, orientation, mass
What directly affects a materials fire resistance
mass, or surface to mass ratio
Mass = ______________
Heat resistance = _________________
heat resistance, time
What type of material breaks before it bends
brittle
What type of material bends before it breaks
ductile
Two types of wood burning characteristics
native wood, engineered wood
What happens to rough cut native wood when exposed to flame?
surface char, slows burn rate
What happens to planed smooth finished native wood when exposed to flame
alligator check, speeding burn rate
At what temp does cold drawn steel lose 55% of its strength?
800 degrees
At what temp does extruded structural steel lose 50% of its strenght?
1100 degrees
At 1100 degrees, how much does a beam expand by?
10 inches
What is the strength of cement mostly dependent on?
Ratio of water to portland cement
When heated what causes concrete to expand and spall?
Moisture
What does a masonry wall rely on to keep it strong?
Axially imposed force
What causes cracks in the binding mortar in masonry walls
heating causes different heat stresses between the blocks and mortar
Slang term for lightweight wooden i-beams and what are they composed of?
I-joists, laminated veneer lumber, oriented strand board
Stud wall is a form of what?
Wall column
What dictates the amount of load a beam can carry or distance it can span?
The distance between the top of the beam and the bottom of the beam
Another name for chord on an I-beam
flange
Material between chords or flanges in beams
Web or stem
Define simple beam
a beam that is supported at the two points near its ends
Define Joist
A wood framing member used to support floors or roof sheeting
Define Purlin
A series of beams placed perpendicularly to other trusses or beams to help support roof decking
What does conventional construction consist of?
Solid wood or steel beams in the floors and roof
What does truss construction consist of?
open-webbed beams
What is the peak sometimes called?
Ridge board
A vaulted ceiling is missing what member?
Ceiling joists
What does a scissor-truss consist of?
Pitches in the bottom chord
3 types of trusses
Triangular, parallel chord truss, arched truss
What is a parallel chord truss?
Both top and bottom chord run in the same plane. Creating a flat roof or floor
Which truss does only the top chord attach to support?
Parallel chord truss
Most common type of truss?
Triangle truss
Two types of arched truss
Rigid frame, bow string
What are the 3 general types of connections
Pinned, rigid, gravity
What are types of pinned connections?
Bolts, screws, nails, rivets
What are types of rigid connections?
embedded rebar, beaded welds, and adhesives
What is a masonry wall pocket for a beam to sit in?
Let
What is a series of post columns and beams used to hold up a building?
Skeletal frame or post and beam
Building with internal load-bearing wall columns and an attached post and beam frame
Center-core
Building with the beams resting solely on the exterior walls are called
Wall-bearing
What building type has exterior walls that do not bear any weight but their own?
Center-core
Define Lamella arch or Summerbell roof
An arched roof that uses a weave of octagon, triangle, or diamond-petterned roof beams to form the arch
What are the four construction influences that help the fire officer classify the building?
Type, era, use , size
What are the 5 building types listed in NFPA 220
Type 1/fire resistive. Type 2/noncombustible Type 3/ordinary Type 4/Heavy timber Type 5/wood frame
Type 2 buildings are more often than not made of what
Steel
What do firefighters call ordinary/type 3 construction?
Taxpayers
What do firefighters call type 4 heavy timber construction?
Mill construction
What does the fire cut do in heavy timber construction?
Release the floor from load bearing walls
In what construction does a wall become an unstable cantilevered beam after the floor and roof fall away?
Type 4 heavy timber
ICF stands for in building construction?
Insulated concrete forming
Which ICF is of most concern to firefighters?
Grid block ICF
The four building eras
Founder era - 1700s to WW1
Industrial era - WW1-WW2
Legacy era - WW2 to roughly 1980s
Lightweight era - 1980s to present
What is an example of Industrial era framing?
Balloon framing
What is an example of Legacy era framing?
Platform framing
What era did drywall replace lath and plaster and plywood replace wood slats on roofs?
Legacy Era
What era saw a gradual transformation away form conventional construction and trusses used more frequently
Legacy era
What changed in 1980s with building codes?
Prescriptive codes transformed into performance codes
What are the elements of building size?
Footprint - single floor square footage
Interior arrangement - volume of space for any one room
number of floors
distance that must be traveled to reach a fire or victims
What is the building classification approach that an ISO should use?
type/era/use/size
5 step process to predict collapse
Classify, determine structural involvement, visualize and trace loads, evaluated time, predict and communicate collapse potential
What color smoke is released when untreated wood is rapidly heated
brownish smoke, a collapse warning sign in lightweight wood construction
What are the 9 historical weak links in building construction?
Connections, overloading, occupancy conversions, trusses, void spaces, stairs, large open interior spaces, parapet walls, facades
According to Niosh alert when should firefighters be evacuated from above or below truss systems?
As soon as the truss is exposed to fire, not according to a time limit
What are the three communications that an ISO can use to communicate collapse potential
Emergency abandonment, Precautionary withdrawal, Planning awareness
