Cantilever Walls
Walls that extend beyond the structure that supports them.
Collapse Zone
The area extending horizontally from the base of the wall to one and one-half times the height of the wall.
Fire-Resistive Construction
Another term for Type I construction; construction that maintains its structural integrity during a fire.
Fire Wall
Fire-rated wall with a specified degree of fire resistance, built of fire-resistive materials and usually extending from the foundation up to and through the roof of a building, that is designed to limit the spread of a fire within a structure or between
Gang Nail
Form of gusset plate. These thin steel plates are punched with acutely V-shaped holes that form sharp prongs on one side that penetrate wooden members to fasten them together.
Green Wood
Wood with high moisture content.
Gusset Plates
Metal or wooden plates used to connect and strengthen the intersections of metal or wooden truss components roof or floor components into a load-bearing unit.
Heavy Fire Loading
Presence of large amounts of combustible materials in an area or a building.
Lightweight Steel Truss
Structural support made from a long steel bar that is bent at a 90-degree angle with flat or angular pieces welded to the top and bottom.
Lightweight Wood Truss
Structural supports constructed of 2 x 3-inch or 2 x 4-inch or 2 x 6-inch (50 mm by 75 mm or 50 mm by 100 mm) members that are connected by gusset plates.
Load-Bearing Wall
Wall that is used for structural support.
Masonry
Bricks, blocks, stones, and unreinforced and reinforced concrete products.
Noncombustible Construction
Another term for Type II construction; construction made of the same materials as fire-resistive construction except that the structural components lack the insulation or other protection of Type I construction.
Nonload-Bearing Wall
Wall, usually interior, that supports only its own weight.
Ordinary Construction
Another term for Type III construction; construction that requires that exterior walls and structural members be made of noncombustible or limited combustible materials.
Partition Wall
Interior non-load bearing wall that separates a space into rooms.
Rain Roof
A second roof constructed over an older roof.
Roof Covering
Final outside cover that is placed on top of a roof deck assembly.
Situational Awareness
Awareness of immediate surroundings.
Veneer Walls
Walls with a surface layer of attractive material laid over a base of common material.
Wood-Frame Construction
Another term for Type V construction; construction that has exterior walls, bearing walls, floors, roofs, and supports made completely or partially of wood or other approved materials of smaller dimensions than those used for heavy-timber construction.
Bowstring truss
a roof assembly with a curved (arched) top chord and a horizontal bottom chord
Column
a vertical supporting member, made of heavy timber
Gypsum
An inorganic product from which plaster and wallboard are constructed. It is unique because it has high water content, and the evaporation of this water absorbs a great deal of heat. Commonly used to provide insulation to steel and wood.
Wooden I-Beam
Also used in lightweight construction.
Fire Load
total potential heat release if a building and its contents burn
Flat Roof
a roof that is flat or nearly flat relative to the horizon
Party Wall
a wall shared by two adjoining buildings, usually a load-bearing wall and a fire wall
Reinforced Concrete
concrete that has been poured into forms that contain an interconnected network of steel rebar
Most common building material used in North America
wood
Primary material used for structural support in the construction of large modern buildings
steel
Has the compressive strength of concrete along with the tensile strength of steel
reinforced concrete
Type I construction
Fire resistive
Commonly used to construct typical single family residence or apartment house of up to 7 stores
Type V construction( Wood frame)
Type IV
Heavy timber
Strengths of Type I Construction (Fire -resistive)
resists direct flame impingement
confines fire well
little collapse potential from effects of fire
impervious to water damage
Weakness of Type I Construction (Fire -resistive)
difficult to breach for access or escape
difficult to ventilate during fire
massive debris following collapse
floors, ceilings,and walls retain heat
Type II
noncombustible
Type of construction resistant to collapse from earthquake due to lightweight and flexibility
Type V (wood frame)
Indicators of building collapse
cracks in walls, floors,ceilings, and roof structures
existing structural instability
loose bricks blocks, or stones falling
deterioration of mortar between masonry
walls that appear to be leaning
structural members that appear distorted
excessive weight
Unprotected lightweight steel and wooden trusses can fail after ___ minutes of exposure to fire
5 to 10
Temperature steel trusses begin to fail
1,000 F
What happens if steel is restrained from movement at its end
buckles and fails in the middle
Two factors with wood's reaction to fire
Size of the wood and its moisture content
Masonry Materials
Includes bricks, stones and concrete blocks, which do not burn and so a variety of masonry walls are used in the construction of fire walls
Uses of Masonry walls
Fire walls
Affect of fire on Mason
Very little efffect on Masonry walls even at high temperatures. Bricks rarely show any signs of loss of integrety or serious deterioration. Stones may spall or lose small portions of their surface when heated. Concrete may crack but will retain most of it
Rapid cooling of Masonry
May cause cracking and can be a common problem in chimney fires.
Cast iron
Rarely used in modern construction, commonly used as exterior veneer in older buildings.
Primary concern for cast iron
The bolts or connections that hold the cast iron to the building can fail.
Steel in Buildings
used for structural support of large modern buildings.
Steel behavior when exposed to heat
Will fail at around 1000 F
Will elongate when heated, 50ft beam up to 4". This can push over load bearing walls
Glass
Not typically used for structural support. Wire glass may perform some thermal protection as separation. heated glass can shatter when hit by cold stream.
Fiberglass
used for insulation purposes. glass is is not a significant fuel. materials used to bind the glass can be combustible and difficult to put out.
NFPA 220
Standards on Types of of Building Construction
Type I
(Fire Resistive) Maintains its structural integrity during a fire and that is intended to allow its occupants time to get out. Consists of mainly reinforced concrete with structural members protected by blow-on insulation or sprinklers. interior contents
Type II
(non-combustible construction) made of the same components as type I except that it lacks the insulation or other protection of type I. All metal buildings fit into this category. one of the primary protection concerns is the contents of the building. oft
Type III Construction
(ordinary Construction) requires that exterior walls and structural members be made of noncombustible or limited combustible materials such as concrete or clay tile blocks
Type IV
(heavy timber construction) interior/exterior walls and structural members be made of noncombustible/limited combustible materials. Solid/laminated wood with no concealed spaces Primary fire hazard is massive amount of combustible contents presented by st
Type V
wood-frame. this has exterior walls, bearing walls, floors, roofs and supports made completely or partially of wood or other approved materials of smaller dimensions. Used for single family homes or apartment house up to 7 stories
When to report unusual conditions
immediately and to your supervisor
2 primary types of dangerous conditions that buildings may pose
conditions that contribute to the spread and intensity of the fire, conditions that make the building Susceptible to collapse
Fire Load
Maximum heat that can be produced if all the combustible materials in a given area burn.
Heavy fire loading
the presence of large amounts of combustible materials in an area or a building. Arrangement of said materials greatly impacts fire development and severity and must be considered analyzing the fire.
Heavy content fire
one of the most critical hazards in commercial and storage facilities becasue the fire can overwhelm the capabilities of a fire sprinkler system.
2 Major factors in the loss of live in fires
combustible furnishings and finishes.
Wooden shakes
these in particular, even when treated with a fire retardant will contribute significantly to the spread of fire. problem in wildfires.
Large open spaces
proper vertical ventilation is essential to slowing the spread of the fire.
Structural Collapse
in almost every case this results from damage to structural system of the building caused by the fire or by fire fighting operations.
Collapse Zone
must be one and a half times the height of the building and extends horizontally from the base of the building.
Suspected collapse
As you and crew exit the building command and any others in the building must be notified. After this no one save someone to place unmanned master stream devices
Most common types of lightweight construction
lightweight steel and wooden trusses
lightweight wooden trusses
constructed of 2x3, 2x4, or 2x6 and are connected by gusset plates(gang nails) which penetrate 3/8" into the wood.
Failure time for lightweight construction
Can fail after 5-10 minutes. Can fail from exposure to heat alone without direct contact from flames.
Trusses
if one member fails the entire truss is likely to fail, no matter what kind of truss it is.
Whats the difference between Type I construction and Type II
Type I has blown-on insulation or automatic sprinklers, when Type II does not
What are types of Heavy Timber
Beams, Columns, Arches, Floors, and roofs, are made of solid or laminated wood with no concealed spaces.