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FLORIDA BUILDING CODE
BCT 1760
Chapter 2
Types of Construction
MICHAEL KNOTEK
27
TYPES OF CONSTRUCTION
GENERAL
The occupancy is considered by hazard; the building itself, housing the occupancy, is
considered by its capacity to resist the hazard.
The interest lies in:
The kinds of building materials use in the building and;
The rating of fire resistance of various parts of the building and the building as a whole
EXAMPLES
Construction or construction material may be classified as combustible or noncombustible,
and unprotected or fire resistive.
For example, a exposed structural steel elements will not ignite or burn, but is not
capable of supporting its design load under the attack of fire for an extended time
period without failure
A masonry wall element is noncombustible and has a fire resistance rating
A wood frame wall, properly framed, with 5/8” type X gypsum wallboard installed properly
on each face is combustible and fire resistive.
The same wall with plywood paneling in place of the gypsum board is combustible and
unprotected
GENERAL
A noncombustible fire-resistive building, it is evident, has a greater degree of fire safety than
a combustible unprotected building and therefore should be considered more hazard
resistant.
As you might expect, these higher types of construction have certain advantages and
privileges under the BUILDING CODE with respect to permitted floor area and height
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Noncombustible
Type
I
Section 602.2
Type
*A& B
II
Section 602.2
*A& B
Exterior or Interior
(bearing or nonbearing)
walls, floors, roofs and
structural elements to be of
noncombustible materials
Combustible / Noncombustible
Type
III
Section 602.3
Type
Section 602.4
IV
*A& B
Exterior walls to be of
noncombustible materials –
Interior walls, any material
provided by Code
** HT
** Heavy Timber
Combustible
Type
Section 602.5
V
All Building elements
* A & B any material provided
by Code
7
TYPE I CONSTRUCTION
TYPE I CONSTRUCTION
Type I buildings to be built throughout of concrete, masonry, or fire-protected steel to satisfy
the dual requirement of noncombustible, fire-resistive construction.
Columns, elements directly supported by columns (such as beams, spandrel beams,
and girders), and other structural elements relating to the total stability constitute
the structural frame.
Curtain walls (nonstructural fillers), floor and roof systems with no immediate
connection to columns, and other structural or nonstructural elements or systems are
not part of the structural frame
29
30
Types IA and IB construction are identical in obvious features only.
In Table 601, for example, the floor construction protection is maintained in either type;
however, Type IA construction presents a higher order of fire protection for exterior and
interior bearing walls, the structural frame, and the roof than does Type IB construction.
Logically, the safer type would have certain design advantages of greater area and
height
TYPE II CONSTRUCTION
TYPE II CONSTRUCTION
If buildings in which the building elements listed in Table 601 are of noncombustible
materials and do not measure up to the levels of fire protection of Type I construction, they
would be classified as Type IIA or IIB
Type IIA is protected throughout with one-hour fire resistance and IIB is unprotected
31
COMBUSTIBLE MATERIALS IN TYPE I AND II CONSTRUCTION
Combustible materials shall be permitted in buildings of Type I or II construction in the
following applications:
Fire-retardant-treated wood shall be permitted in:
Nonbearing partitions where the required fire-resistance rating is 2 hours or less
Nonbearing exterior walls where no fire rating is required
Roof construction as permitted in Table 601, note c, item3
Thermal and acoustical insulation, other than foam plastics, having a flame spread
index of not more than 25
Insulation placed between two layers of noncombustible materials without an
intervening airspace shall be allowed to have a flame spread index of not more
than 100
Insulation installed between a finished floor and solid decking without intervening
airspace shall be allowed to have a flame spread index of not more than 200
Foam plastics
Roof covering that have an A, B, or C classification
Interior floor finish and interior finish, trim and millwork such as doors, door frames,
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window sashes and frames
Where not installed over 15 feet above grade, show windows, nailing or furring strips,
wooden bulkheads below show windows, their frames, aprons and show cases
Finished flooring applied directly in the floor slab or to wood sleepers that are
firestopped
Partitions dividing portions of stores, offices or similar places occupied by one tenant
only and which do not establish a corridor serving an occupant load of 30 or more
shall be permitted to be constructed of fire-retardant-treated wood, 1-hour fireresistance-rated construction or of wood panels or similar light construction up to 6
feet in height
Platforms
Combustible exterior wall coverings, balconies, bay or oriel windows, or similar
appendages
Blocking such as for handrails, millwork, cabinets, and windows and door frames
Light-transmitting plastics
Mastics and caulking materials applied to provide flexible seals between components
of exterior wall construction
Exterior plastic veneer
Nailing or furring strips
Heavy timber
Aggregates, component materials and admixtures
Sprayed cementitious and mineral fiber fire-resistance-rated materials
Materials used to protect penetrations in fire-resistance-rated assemblies
Materials used to protect joints in fire-resistance-rated assemblies
Materials allowed in the concealed spaces of buildings of Type I and II construction
Materials exposed within plenums
Ducts – The use of nonmetallic ducts shall be permitted
Piping – The use of combustible materials shall be permitted
Electrical – The use of electrical wiring methods with combustible insulation, tubing,
raceways, and related components shall be permitted
33
TYPE III CONSTRUCTION
TYPE III CONSTRUCTION
Type III construction is that type of construction in which the exterior walls are of
noncombustible materials and the interior building elements are of any materials permitted
by code.
Fire-retardant-treated wood framing shall be permitted within exterior wall assemblies
of a 2-hour rating or less.
TYPE IV CONSTRUCTION
TYPE IV CONSTRUCTION
Type IV (Heavy Timber, HT) is that type of construction in which the exterior walls are of
noncombustible materials and the interior building elements are of solid or laminated wood
without concealed spaces.
34
Firefighter feel more comfortable fighting fire in a building with unprotected timber
elements than in a building with unprotected steel members.
Wood may burn and char, but it will continue to maintain structural integrity under high
temperature conditions that could cause unprotected steel to collapse.
Columns – Wood columns shall be sawn or glued laminated and shall not be less than 8”,
nominal, in any dimension where supporting floor loads and not less than 6” nominal in
width and not less than 8” nominal in depth where supporting roof and ceiling loads only.
Columns shall be continuous or superimposed and connected in an approved manner
Floor framing – Wood beams and girders shall be sawn or glued-laminated timber and shall
be not less than 6” nominal in width and not less than 10” nominal in depth
Framed timber trusses supporting floor loads shall have members of not less than 8”
nominal in any dimensions
Roof framing – Wood-frame or glued-laminated for roof construction, which spring from the
floor line or from grade and do not support floor loads, shall have members not less than 6”
nominal in width and have less than 8” nominal in depth for the lower half of the height
and not less than 6” nominal in depth for the upper half.
Framed or glued-laminated arches for roof construction that spring from the top of walls or
wall abutments, framed timber trusses and other roof framing, which do not support floor
loads, shall have members not less than 4” nominal in width and not less than 6” nominal in
depth
35
Floors – Floors shall be without concealed spaces and shall be of sawn or glued-laminated
planks, splined or tongue-and-groove, of not less than 3” nominal in thickness covered with
I” nominal dimension tongue-and-groove flooring, laid crosswise or diagonally, or 0.5”
particleboard or planks not less than 4” nominal in width set on edge close together and
well spiked and covered with I” nominal dimension flooring or 15/32” wood structural panel
or 0.5” particleboard.
Roof – Roofs shall be without concealed spaces and wood roof decks shall be sawn or glued
laminated, splined or tongue-and-groove plank, not less than 2” thick, 1 1/8” thick wood
structural panel (exterior glue), or of planks not less than 3” nominal in width, set on edge
close together and laid as required for floors
Partitions – shall be of solid wood construction formed by not less than two layers of 1”
matched boards or laminated construction 4” thick, or of 1-hour fire-resistance-rated
construction
Exterior structural members – Where a horizontal separation of 20 feet or more is provided,
wood columns and arches conforming to heavy timber sizes shall be permitted to be used
externally
TYPE V CONSTRUCTION
TYPE V CONSTRUCTION
Type V - construction is that type of construction in which the structural elements, exterior
walls and interior walls are of any materials permitted by code
36
TABLES 601 & 602
Table 601
37
Table 602
38