Fire Inspection and Code
Enforcement, 7th Edition
Chapter 5 — Building Construction:
Materials and Structural Systems
Inspector II
Learning Objective 1
Discuss the common construction
materials used in the building of
structures.
Inspector II
5–1
Building Materials
• Usefulness determined by properties or
characteristics
• Shared properties
– Combustibility
– Thermal conductivity
– Rate of thermal expansion
– Variation of strength with temperature
Inspector II
5–2
Wood
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•
•
•
•
Cheap to produce
Renewable
Disadvantages
Strength varies significantly
May be treated with fire-retardant
chemicals
Inspector II
5–3
DISCUSSION QUESTION
What are some possible defects of
wood?
Inspector II
5–4
Learning Objective 2
Describe the common forms of wood
products.
Inspector II
5–5
Solid Lumber
• Boards
• Dimension lumber
• Timbers
Inspector II
5–6
Laminated Members
• Small, flat strips jointed together with
glue
• Advantage
• Scarf joints
• Permits higher
quality control
Inspector II
5–7
Panels
• Used for roofs, subflooring, and siding
• Require less labor
• Graded for structural use and exposure
durability
Inspector II
5–8
Manufactured Members
• Prefabricated from components then
shipped to construction site for erection
• Permit greater quality control and
efficient use of materials
• Panels
• Common uses
Inspector II
5–9
Learning Objective 3
Describe the methods used to reduce
the combustibility of wood.
Inspector II
5–10
Fire-Retardant Treatment
• Permitted by building codes for certain
applications
• Treated wood
– Resists ignition
– Has increased fire endurance
– Should not be confused with materials that
are fire resistive
Inspector II
5–11
Surface Coating
• Primarily used to reduce the surface
burning of wood
Inspector II
5–12
Pressure Impregnation
• Process
• Advantage
• Uses a number of fire-retardant
chemicals
Inspector II
5–13
DISCUSSION QUESTION
What types of fire-retardant chemicals
may be used in pressure impregnation?
Inspector II
5–14
Learning Objective 4
Describe the forms in which masonry
materials are produced.
Inspector II
5–15
Masonry
• Fundamental construction technique —
Stacking individual units on top of one
another and bonding them into a solid
mass
• Inherently resistant to fire and insects
• Disadvantages
• Mortar
Inspector II
5–16
Brick
• Produced from variety of locally
available clay and shale
• Manufactured by placing clay in molds
then drying bricks
• Fired in kiln;
intense heat
converts to a
ceramic material
Inspector II
5–17
Concrete Block
• Most commonly used is hollow concrete
block
• Also produced as bricks or solid blocks
Inspector II
5–18
Stone
• Pieces of rock removed
from quarry and cut to
desired shape and size
• Principal types used in
construction
Inspector II
5–19
DISCUSSION QUESTION
In what ways can stone be used in
construction?
Inspector II
5–20
Clay Tile Block
• Used for foundations and walls where
clay is available as a building material
• Deteriorate over time and are
susceptible to damage from water and
freezing temperatures
Inspector II
5–21
Gypsum Blocks
• Can be used for internal partitions but
are not applicable for exterior use
• Have diminished in modern practice
Inspector II
5–22
Learning Objective 5
Discuss the use of concrete as a
building material.
Inspector II
5–23
Concrete
• Types
• Produced from portland cement, coarse
and fine aggregates, and water
• Strength depends on:
– Admixtures
– Reinforcement
– Water-to-cement ratio
Inspector II
5–24
DISCUSSION QUESTION
What are the advantages of concrete as
a building material?
Inspector II
5–25
Learning Objective 6
Compare the advantages and
disadvantages of steel as a construction
material.
Inspector II
5–26
Advantages of Steel
• Low carbon content
• Strongest of structural materials
• Subject to tight
quality control
• Relatively expensive,
but can be used in
smaller quantities
Inspector II
5–27
Disadvantages of Steel
• Melts when exposed to tremendous
levels of heat
• Tendency to rust
• Loss of strength
when exposed to
heat of fire
Courtesy of Ed Prendergast
Inspector II
5–28
DISCUSSION QUESTION
Upon what factors does the quickness
with which unprotected steel fails
depend?
Inspector II
5–29
Fire Protection of Steel
• Most common method — Use of
insulating material
• Lightweight materials
• Sprayed-on coatings
• Intumescent coatings
Inspector II
5–30
Learning Objective 7
Discuss the use of other metals as
construction materials.
Inspector II
5–31
Aluminum
• Limited in use by several factors
• Will melt under fire conditions
• If used for roofing, does not provide
safe surface for firefighters
• May become electrically energized
Inspector II
5–32
Other Metals
• Cast iron — Brittle and tends to fail
• Copper — Limited in use; used for
decorative purposes
• Zinc — Limited in use; used for
construction hardware and in
production of nails
Inspector II
5–33
Learning Objective 8
Describe the uses of glass in
construction.
Inspector II
5–34
Types of Glass
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•
•
•
•
Ordinary, single-strength annealed
Heat-strengthened
Fully tempered
Laminated
Glass block
Inspector II
5–35
Types of Glass Used Where Fire
Resistance is Required
• Wired glass
• Fire-rated glass
Inspector II
5–36
DISCUSSION QUESTION
In what types of applications might
wired glass be desirable?
Inspector II
5–37
Learning Objective 9
Explain the use of gypsum board in
building construction.
Inspector II
5–38
Gypsum Board
•
•
•
•
Inexpensive substitute
Used in fire-resistive assemblies
Production
Exposure to fire
Inspector II
5–39
Types and Applications of
Gypsum Board
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•
•
•
•
•
•
Regular
Water-resistant
Type X
Type C
Foil-backed
Gypsum backing board
Coreboard
Inspector II
5–40
Learning Objective 10
Discuss the use of plastic construction
materials.
Inspector II
5–41
Plastic Construction Materials
• Synthetic, organic materials of high
molecular weight formed by pressure,
heat, extrusion, and other methods
• Types
• Used for number of construction
components
• Variations
(Continued)
Inspector II
5–42
Plastic Construction Materials
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•
•
•
•
•
•
Strength — Close to wood
Not used for structural applications
Increasing in use
Flammability
Fire hazards
Thermal barriers
Exterior veneers
Inspector II
5–43
DISCUSSION QUESTION
What are some exceptions to the
thickness requirement of thermal
barriers?
Inspector II
5–44
Learning Objective 11
Explain the uses, advantages, and
disadvantages of fabric as a
construction material.
Inspector II
5–45
Fabric
• Part of enclosing surfaces of structures
known as membrane structures
• Used as part of
existing walls
and roofs of
permanent
structures
Inspector II
5–46
Advantages of Fabric
• Weighs less
• Erects in less time
• Can flex and absorb some stresses from
seismic and wind forces
• Permits development of innovative
architectural shapes
Inspector II
5–47
Disadvantages of Fabric
• Cannot support compressive forces
• Must include support system
• Cannot be used to support building
appliances
• Considerably thinner than other
assemblies
• Must use noncombustible materials
Inspector II
5–48
Learning Objective 12
Describe the uses and advantages of
concrete in construction of buildings.
Inspector II
5–49
Uses of Concrete
• In construction of all buildings
• Most commonly to form:
– Foundation stem walls
– Floor slabs
– Driveways
– Walks
Inspector II
5–50
Precast Concrete
• Placed in forms and cured at precasting
plant away from job site
• Advantages
– Higher degree of quality control
– Buildings can be built using whole precast
modular units
– Elements can be assembled in several
ways
(Continued)
Inspector II
5–51
Precast Concrete
Inspector II
5–52
DISCUSSION QUESTION
What are the potential disadvantages of
using precast concrete?
Inspector II
5–53
Cast-in-Place Concrete
• Does not develop strength until after
placed
• Typical design — Concrete frame
– Flat-slab concrete frame
– Slab and beam frame
– Waffle construction
Inspector II
5–54
Concrete Systems
• Curtain wall
– Building’s exterior enclosure
– Made of variety of materials
• Difficulties
• Solutions
• Knowledge of concrete system
Inspector II
5–55
Learning Objective 13
Explain how steel components are used
in construction.
Inspector II
5–56
Steel
• Construction of structural framework
that supports floors, roof, and exterior
walls
• Can be used in several different
techniques
Inspector II
5–57
Beam and Girder Frames
• Connection design extremely important
• Must include means to resist wind load
and other lateral forces
• Classifications
– Rigid
– Semirigid
– Simple
Inspector II
5–58
Steel Trusses
• Can carry loads across greater spans
more economically than beams
• Open web joist
• Joist girder
Inspector II
5–59
DISCUSSION QUESTIONS
How can open web joists be
created?
In what types of construction are rigid
steel frames used?
Inspector II
5–60
Rigid Frames
• Allow increase in interior clear space
• Fabricated by welding or bolting steel
shapes and plates together
• Crown and knees are designed as rigid
joints with no rotation between
members.
Inspector II
5–61
Steel Arches
• Support roofs on buildings where large
unobstructed floors are needed
• Girder arches
• Trussed arch
Inspector II
5–62
Steel Suspension Systems
• Strength of steel allows use in slender
forms
• Subject to buckling
• Limited to support
of tension forces
• Suspension roof
systems
Inspector II
5–63
Steel Columns
• Cross section must be small compared
to length
• Have greater possibility of buckling
• Can vary from simple to complex
• Critical to structural integrity
Inspector II
5–64
DISCUSSION QUESTION
What are the most common column
cross sections of steel columns?
Inspector II
5–65
Learning Objective 14
Describe the use of masonry
construction.
Inspector II
5–66
Use of Masonry Construction
• Load-bearing walls
• Non-load-bearing curtain or partition
walls
• Architectural veneer
• Exterior walls
Inspector II
5–67
Masonry Walls
• Thickness varies
and depends on
several factors
• Strength and
stability
(Cont.)
Inspector II
5–68
DISCUSSION QUESTION
What is the purpose of a vertical cavity
between the exterior wythe and interior
wythes?
Inspector II
5–69
Masonry Walls
• Reinforcement
(Continued)
Inspector II
5–70
Masonry Walls
• Openings
• Parapet
Inspector II
5–71
DISCUSSION QUESTION
What problem is encountered when
openings are created in masonry walls?
Inspector II
5–72
Interior Structural Framing
• Classifications
• Beam pocket
– Indentation in masonry
wall in which wood
joists or beams rest
• Fire cut
Inspector II
5–73
Fire Resistance of Masonry Walls
• Depends on type of masonry units and
thickness of wall
• Ratings from 2 to 4 hours
• Likely fire behavior determined by
several factors
• Exterior fire-resistive walls
Inspector II
5–74
Deterioration of Masonry Walls
• Result of erosion of mortar
• Causes formation of cracks and
misalignment
• Can be affected by
rotting wooden
interior members
• Repair
Inspector II
5–75
Learning Objective 15
Describe the use of wood construction.
Inspector II
5–76
Wood
• Fundamental structural material
• Distinguishing characteristic — Basic
structural system is combustible
– Contributes fuel to fire
– Structural integrity lost as wood is
consumed
– Lighter weight wood assemblies increase
speed of failure
Inspector II
5–77
DISCUSSION QUESTION
How do the concealed spaces created
by wood construction affect the
structure in the event of a fire?
Inspector II
5–78
Heavy Timber
• Structural support provided by
•
•
•
•
framework of beams and columns of
wooden timbers
Basic concept
Design
Connection between members
Mortise and tenon joint
Inspector II
5–79
Post and Beam
• Columns and beams are of dimensions
less than those used in heavy timber
framing but greater than light-frame
construction
• Leaves interior
wood surface
exposed
– Advantage
Inspector II
5–80
Light Wood
• Makes use of 2-inch (50 mm) nominal
pieces of lumber
• Walls formed from studs
• Floors supported by joists or trusses
• Inclined roofs supported by rafters or
light trusses
(Continued)
Inspector II
5–81
Light Wood
• Balloon framing
– Used in wood frame buildings composed of
closely spaced studs continuous from sill to
top plate of roof line
– Characteristics
• Platform framing
– Characteristics
– Greater shrinkage than balloon frame
Inspector II
5–82
(Continued)
Light Wood
Inspector II
5–83
Exterior Wall Materials
• Sheathing
• Siding material
• Insulation
– Loose fill material
– Blown or packed by hand
– Foam plastics
Inspector II
5–84
Brick Veneer
• Brick styling at less cost
• Tied to wood-frame wall
every 16 inches (400 mm)
• Adds to thermal insulating
value of wall
• Difficult to determine
from outside
Inspector II
5–85
DISCUSSION QUESTION
How can you tell whether a building
utilizes brick-veneer walls or masonry
bearing walls?
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5–86
Summary
• Knowledge of the materials used to
construct a building and the common
structural components of buildings is
necessary to evaluate the structure’s
ability to resist the effects of fire.
(Continued)
Inspector II
5–87
Summary
• Combined with the construction types,
the inspector can categorize a building
and determine the necessary code
enforcement approaches and
applications that apply to it.
(Continued)
Inspector II
5–88
Summary
• The inspector must have a strong
working knowledge of these building
elements and how they reduce risk in
case a fire does occur.
Inspector II
5–89
Review Questions
1. How can stone be used in
construction?
2. Why does cast iron tend to fail?
3. Discuss cast-in-place concrete
systems.
(Continued)
Inspector II
5–90
Review Questions
4. How are joist girders used?
5. What wood-framing systems are most
frequently encountered?
Inspector II
5–91