Chapter 4 Building Construction Flashcards
All trusses constructed prior to the late 1960’s have a common code deficiency.
The bottom cord members have inadequate tensile strength to support roof loads allowed by the current existing code.
Common building materials include
Wood, Masonry, Metals, Reinforced Concrete, Gypsum, Lath and Plaster, Glass/Fiberglass, Plastic, Composite materials.
The most common building material in north america
Wood
Two factors that affect how wood react to fire.
Size and moisture content
Lumber of small dimensions needs to be protected by…….to increase its resistance or heat and fire.
gypsum or other insulation
Wood may be ……….to reduce the speed at which it ignites and burns.
pressure treated with fire-retardant chemicals
Green Wood
Wood with high moisture content
Pressure treating wood can weaken the woods strength by as much as
25%
Roofs, decks, walls, and sub floors are all commonly made of
OSB
Includes bricks,stones, and concrete blocks
Masonary
These may crack, but they usually retain most of their strength and basic structural stability.
Concrete Blocks
Veneer Wall
Walls with a surface layer of attractive material laid over a base of common material.
In masonry walls this may become degraded by heat and may show signs of weakening.
Mortar
Spalling
Expansion of excess moisture within masonry materials due to exposure to heat of a fire, resulting in tensile forces within the material, and causing it to break apart. May cause explosive pitting or chipping of the materials surface.
Metal building materials commonly include
cast iron, steel, aluminum, other metals.
Metal building materials are used for
structural support, decorative coverings, stairs, door and window frames, duct work, pipes, and fasteners.
The effects of heat and fire on metal materials is dependent on….
Metal type, whether it is exposed or not.
Two types of Iron that can be found in North America
Wrought Iron, Cast Iron
Commonly used metal in construction in the 1900’s.
Cast Iron.
With stands heat and fire but may crack if rapidly cooled.
Cast Iron
Metal used in construction in the 1800’s.
Wrought Iron
Used today as decoration on gates, fences, and railings.
Wrought Iron
Rivet or welded
Wrought Iron
Bolted or screwed
Cast Iron
Primary material used for structural support in large modern buildings.
Steel
When heated to 1000 degrees a 50 foot steel beam can elongate how many inches?
4
Failure of steel members should be expected at how many degrees?
1000
Reduces the effect of heat on steel structural members
Spray on concrete or insulation
Fire fighter can use ……………to cool steel and prevent or slow down its elongation.
water
Curtain wall
A non-load bearing wall, often glass or steel, fixed to the outside of a building and serving especially as cladding.
Can create entanglement hazards for firefighters.
Drop down ceiling framing and support wires.
Will be affected by heat more rapidly then steel
Aluminum
Provides the compression strength of concrete and the tensile strength of steel.
Reinforced concrete
Also known as drywall or sheetrock, also a inorganic product.
Gypsum
Gypsum provides a excellent heat and fire resistance due to
Its high water content.
Commonly used to insulate steel and structural members.
Gypsum
A process rather then a single material
Lath and Plaster
Generally found in buildings built prior to 1950
Lath and Plaster
May replace the lath for ceilings in some homes
Wire Mesh
Not used in structural supports. Used in sheets for doors and windows. Used in block form for non load bearing walls.
Glass
This type of glass may provide some thermal protection.
wire reinforced glass
Used as a insulating material
Fiberglass
A mineral fiber used as insulation before the 1970’s
Asbestos
Used in the 1970’s to insulate walls, caused high levels of formaldehyde emissions.
Urea Formaldehyde Foam Insulation (UFFI)
Most common insulation material prior to 1960’s.
Mineral wool
80% recycled newspaper
cellulose
Used in the exterior walls of hybrid or natural (green) construction.
Straw
Used as siding, pipes, decorative moldings, wall coverings, mantel pieces.
Plastics
Manufactured by combining two or more different materials. Results in lightweight, high structural strength, chemical resistant, corrosion resistant, and heat resistant material.
Composite Materials
Composite material examples
Finger jointed timber, Laminated Timber, Medium density fiber board, Particle board, Synthetic wood.
Used in particle board, it can off gas causing a health risk.
Urea Formaldyhyde
The type of building construction is determined by
the materials used and how well those materials resist fire.
NFPA 5000
Building construction and Safety code.
The two most recognized building codes in the U.S.
NFPA 5000 and International Code Council International Building codes.
Factory built homes are usually regulated by the …….and not local building codes.
Department of housing and urban development.
These buildings may be exempt from local building codes.
Federal and/or state government buildings.
Every building is composed of these three building elements.
Structural frame, Floor construction, Roof construction
Also known as fire-resistive construction.
Type I
Provides the highest level of protection from fire, spread, and collapse. All structural materials are limited or noncombustible materials. Structural components must resist fire for 3-4 hours.
Type I
Also known as noncombustible or limited combustible construction.
Type II
Are composed of materials that will not add to the fire potential. Fire resistance rating is usually half of Type I. More prone to collapse because of lighter weight materials. Usually used when fire risk is low or sprinkler installed can meet the fire load of the contents.
Type II
Fire resistance rating
Rating assigned to a material or assembly after a standardized testing by an independent testing organization. identifies the amount of time a material or assembly will resist a typical fire, as measured on a standard time-temperature curve.
Also known as Ordinary Construction
Type III
Exterior walls and structural members are made of noncombustible materials and interior walls, columns, beams, floors, and roofs, are completely or partially wood.
Type III
May contain voids that will contribute to rapid fire spread unless fire stops have been put in place. May also carry a larger load then for what is was designed due to renovations or occupancy type change
Type III
Also known as heavy timber/ mill construction.
Type IV
Characterized by the used of lumber greater then 8 inches as structural members. Very low collapse risk. The lumbers own char provides insulating effect reducing heat from penetrating into the core of a structural member.Non combustible exterior walls. No void spaces.
Type IV
Type of beam that may fail when exposed to fire because the glue holding it together may fail.
GluLam beams
Also known as wood frame or stick frame construction.
Type V
Exterior load bearing walls are composed of wood. Veneer over wood exterior provides little to no protection. Most single family homes but also may be found in muti story structures.
Type V
Most structure built in the northern climates mandate 6 inch ……….for increased insulation.
exterior wall cavities.
Current estimates indicate that 25% of homes are ……
manufactured homes
Manufacturer home built before 1976 have less……….then those of current construction.
fire resistance
May provide a additional oxygen source in manufactured homes.
open crawl space
Types of Factory built homes.
Manufactured, Modular, Panelized,Pre-cut, Hybrid.
Most common type of factory built home and cheapest.
Manufactured
Sections can be attached horizontal and vertically to make a home. Must conform to local building codes.
Modular homes
Made of panels of foam sandwiched between sheets of plywood. Normally 8 feet wide by up to 40 feet long. Self supporting so no framing members needed.
Panelized Homes
Come in varieties such as pole houses, post an beam, log homes, A-frame, and geodesic domes. Individual parts that assembled on site.
Pre-cut Homes
Includes elements of both the modular design and panelized design.
Hybrid modular homes
Structures may also be classified according to their intended use or…….
occupancy
Structures are divided into two types of occupancies which are ?
Single use or Separated Use.
If a structure contains multiple types of use it is classified according to …..
its primary use.