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Objectives (1 of 3)
• Describe the characteristics of the following building materials: masonry, concrete, steel, glass, gypsum board, and wood.
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Objectives (2 of 3)
• List the characteristics of each of the following types of building construction: fire-resistive construction, noncombustible construction, ordinary construction, heavy timber construction, and wood-frame construction.
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Objectives (3 of 3)
• Describe how each of the five types of building construction react to fire.
• Describe the function of each of the following building components: foundations, floors, ceilings, roofs, trusses, walls, doors, windows, interior finishes, and floor coverings.
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Introduction (1 of 2)
• Knowing building construction enables fire fighters to:
– Predict how a fire will spread– Make determinations about structural integrity– Recognize warning signs of imminent
collapse
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Introduction (2 of 2)
• Fire risks also depend on occupancy and contents.
• Occupancy: how a building is used
• Contents: vary, but usually related to building use
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Construction Material Properties and Fire Behavior
• Key factors affecting combustibility:– Combustibility– Thermal conductivity– Loss of strength when heated– Rate of thermal expansion
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Types of Construction Materials
• Masonry• Concrete• Steel and other metals• Glass• Gypsum board• Wood• Plastics
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Masonry
• Inherently fire-resistive
• Poor conductor of heat
• Openings can allow fire to spread.
• With prolonged exposure to fire, masonry can collapse.
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Concrete
• Inherently fire-resistive
• Poor conductor of heat
• Strong under compression
• Weak under tension
• Can be damaged through exposure to fire
– Spalling
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Steel (1 of 2)
• Strongest material in common use
• Strong in both compression and tension
• Will rust if exposed to air and moisture
• Not fire-resistive
• Good conductor of heat
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Steel (2 of 2)
• Expands and loses strength when heated
• Any sign of bending, sagging, or stretching indicates immediate risk of failure.
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Other Metals
• Aluminum– Often melts and drips in fires
• Copper– Primarily used for piping and wiring
• Zinc– Primarily used as a protective coating for
metals
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Glass
• Noncombustible, but not fire-resistive
• Ordinary (non-treated) glass will break when exposed to flame.
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Gypsum Board (1 of 2)
• Not a strong structural material• Used mainly for finishing • Very good insulator• Limited combustibility
– Paper will burn, but gypsum itself will not.
– Often used as a firestop
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Gypsum Board (2 of 2)
• Prolonged exposure to fire will cause failure.
– Moisture in the material will evaporate causing deterioration.
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Wood
• Most common building material
• Highly combustible
• Weakens when heated
• Fire-retardant chemicals can weaken wood.
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Plastics
• Rarely used for structural support
• Combustibility varies
• Many plastics release dense, toxic smoke when they burn.
• Thermoplastic materials melt and drip.
• Thermoset materials lose strength but will not melt.
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Construction Type Determination
• Classification based on combustibility and fire resistance
• Codes specify construction type required based on:
– Height– Area– Occupancy– Location
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Types of Construction
• Type I: Fire-Resistive
• Type II: Noncombustible
• Type III: Ordinary
• Type IV: Heavy Timber
• Type V: Wood Frame
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Type I: Fire-Resistive (1 of 2)
• All structural components must be noncombustible.
• Used for:– Large numbers of
people– Tall or large area– Special occupancies
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Type I: Fire-Resistive (2 of 2)
• Building materials should not provide fuel for a fire.– Contents may burn but the building should not.
• Steel framing must be protected.• Fires can be very hot and hard to ventilate.• In extreme conditions Type I buildings can
collapse.
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Type II: Noncombustible (1 of 2)
• All structural components must be noncombustible.
• Fire-resistive requirements are less stringent than Type I.
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Type II: Noncombustible (2 of 2)
• Structural components contribute little or no fuel.
• Fire severity is determined by contents.
• Most common in single-story warehouses or factories
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Type III: Ordinary (1 of 2)
• Used in a wide range of buildings
• Masonry exterior walls support floors and roof.
• Usually limited to no more than four stories
• Limited fire resistance requirements
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Type III: Ordinary (2 of 2)
• Two separate fire loads:– Construction materials– Contents
• Fire resistance depends on building age and local building codes.
• Exterior walls, floors, and roof are connected.
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Type IV: Heavy Timber (1 of 2)
• Exterior masonry walls
• Interior structural elements, floors, and roof of wood
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Type IV: Heavy Timber (2 of 2)
• No concealed spaces or voids
• Used for buildings as tall as eight stories
• Open spaces suitable for manufacturing and storage
• New Type IV construction is rare.
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Type V: Wood Frame (1 of 3)
• Most common type of construction in use
• All major components are wood or other combustible materials.– Can rapidly become
fully involved– Collapse frequently
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Type V: Wood Frame (2 of 3)
• Used in buildings of up to four stories
• Wooden I-beams and trusses– Just strong enough to carry required load– No built-in safety margin– Collapse early and suddenly
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Type V: Wood Frame (3 of 3)
• Balloon-frame construction– Exterior walls assembled
with continuous wood studs from the basement to the roof.
• Platform-frame construction– Exterior wall studs not
continuous.
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Building Components
• Foundation
• Floors and ceilings
• Roofs
• Trusses
• Walls
• Doors and windows
• Interior finishes and floor coverings
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Foundation
• Ensures building is firmly planted
• Helps keep all other components connected
• Weak or shifting foundations can cause collapse.
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Floors and Ceilings (1 of 2)
• Fire-Resistive Floors– Floor-ceiling system designed to prevent
vertical fire spread– If space above ceiling is not partitioned or
sprinklered, fire can quickly extend horizontally across a large area.
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Floors and Ceilings (2 of 2)
• Wood-Supported Floors– Heavy-timber floors can often contain a
fire for an hour or more.– Conventional wood flooring burns readily
and can fail in as little as 20 minutes.– Modern, lightweight wood I-beams and
trusses• Little fire resistance
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Roofs
• Not designed to be as strong as floors
• Three primary designs:– Pitched roofs– Curved roofs– Flat roofs
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Pitched Roofs
• Sloped or inclined• Can be gable, hip,
mansard, gambrel, or lean-to
• Usually supported by rafters or trusses
• Require some sort of roof covering
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Curved Roofs
• Used for large buildings that require large, open interiors
– Supermarkets– Warehouses– Industrial buildings
• Usually supported by bowstring trusses or arches
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Flat Roofs (1 of 2)
• Usually found on houses, apartment buildings, warehouses, factories, schools, and hospitals
• Have a slight slope for drainage
• Wood support structures use solid wood beams and joists.
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Flat Roofs (2 of 2)
• Lightweight construction techniques employ wood I-beams and trusses.
• Open-web steel trusses (bar joists) often used for support
• Most coverings highly combustible
• Ventilation may involve cutting through many layers of roofing.
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Trusses (1 of 2)
• Triangular geometry creates a strong, rigid structure.
• Usually prefabricated wood or steel
• Three types:– Parallel chord– Pitched chord– Bowstring
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Trusses (2 of 2)
• Parallel chord– Used for flat roofs and floors
• Pitched chord– Used for pitched roofs
• Bowstring– Used for curved roofs
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Walls
• Most visible part of a building
• Constructed of a variety of materials
• Walls are:– Load-bearing– Nonbearing– Specialized
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Load-Bearing Walls
• Give structural support
• Either interior or exterior
• Support both “dead load” and “live load”
• Damaged wall can result in collapse
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Nonbearing Walls
• Support only their own weight
• Can be breached or removed without compromising structural integrity
• Either interior or exterior
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Specialized Walls (1 of 2)
• Party walls– Common to two properties– Almost always load-bearing– Often a fire wall
• Fire walls– Designed to limit horizontal fire spread– Extend from foundation through roof– Constructed of fire-resistant materials
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Specialized Walls (2 of 2)
• Fire partitions– Interior walls that extend from a floor to underside
of floor above
• Fire enclosures– Fire-rated assemblies that enclose vertical
openings
• Curtain walls– Nonbearing exterior walls attached to the outside
of a building
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Walls
• Solid, load-bearing masonry walls can reach six stories high.
• Nonbearing masonry walls can reach almost any height.
• Never assume that exterior walls are masonry.
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Doors
• Can be used for entry, exit, light, and ventilation
• Mostly constructed of wood or metal– Hollow-core wood doors offer little fire
resistance.– Solid-core doors provide some fire
resistance.– Metal doors more durable and fire-
resistant.
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Window Assemblies
• Used for light, ventilation, entry, and exit
• Window type depends on a variety of factors.
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Fire Doors and Fire Windows(1 of 2)
• Constructed to prevent spread of flames, heat, and smoke
• Must meet NFPA 80• Labeled according to
approved-use– Class A– Class B– Class C– Class D– Class E
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Fire Doors and Fire Windows(2 of 2)
• Fire windows are used when a window is needed in a required fire-resistant wall.
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Interior Finishesand Floor Coverings
• Finishes and coverings are exposed interior surfaces of a building.
• Different interior finish materials contribute in various ways to a building fire.
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Construction or Demolition
• Construction or demolition sites pose special problems for fire fighters.
• Built-in fire protection features are often missing.
• Fire-resistive enclosures can be missing.
• Often unoccupied for long periods
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Summary (1 of 2)
• Many materials are used in building construction, and each material reacts differently to heat and fire.
• The five types of building construction each have their own strengths and weaknesses and differing levels of resistance to fire.
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Summary (2 of 2)
• Buildings contain a variety of parts or components.
• Materials used in building components vary.
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