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