International Building Code Section 720


International Building Code 720.1

General. The provisions of this section contain prescriptive
details of fire-resistance-rated building elements. The
materials of construction listed in Tables 720.1(1), 720.1(2),
and 720.1(3) shall be assumed to have the fire-resistance ratings
prescribed therein. Where materials that change the capacity
for heat dissipation are incorporated into a
fire-resistance-rated assembly, fire test results or other substantiating
data shall be made available to the building official to
show that the required fire-resistance-rating time period is not
reduced.

Thickness of protective coverings. The thickness
of fire-resistant materials required for protection of structural
members shall be not less than set forth in Table
720.1(1), except as modified in this section. The figures
shown shall be the net thickness of the protecting materials
and shall not include any hollowspace in back of the protection.

Unit masonry protection. Where required, metal
ties shall be embedded in bed joints of unit masonry for protection
of steel columns. Such ties shall be as set forth in
Table 720.1(1) or be equivalent thereto.

Reinforcement for cast-in-place concrete column
protection. Cast-in-place concrete protection for steel
columns shall be reinforced at the edges of such members
with wire ties of not less than 0.18 inch (4.6 mm) in diameter
wound spirally around the columns on a pitch of not more
than 8 inches (203 mm) or by equivalent reinforcement.

Plaster application. The finish coat is not required
for plaster protective coatings where they comply with the
design mix and thickness requirements of Tables 720.1(1),
720.1(2) and 720.1(3).

Bonded prestressed concrete tendons. For members
having a single tendon or more than one tendon
installed with equal concrete cover measured from the nearest
surface, the cover shall not be less than that set forth in
Table 720.1(1). For members having multiple tendons
installed with variable concrete cover, the average tendon
cover shall not be less than that set forth in Table 720.1(1),
provided:
1. The clearance from each tendon to the nearest
exposed surface is used to determine the average
cover.
2. In no case can the clear cover for individual tendons
be less than one-half of that set forth in Table
720.1(1). A minimum cover of 0.75 inch (19.1 mm)
for slabs and 1 inch (25 mm) for beams is required for
any aggregate concrete.
3. For the purpose of establishing a fire-resistance rating,
tendons having a clear covering less than that set
forth in Table 720.1(1) shall not contribute more than
50 percent of the required ultimate moment capacity
for members less than 350 square inches (0.226m2) in
cross-sectional area and 65 percent for larger members.
For structural design purposes, however, tendons
having a reduced cover are assumed to be fully
effective.

International Building Code 720.1.1

Thickness of protective coverings. The thickness
of fire-resistant materials required for protection of structural
members shall be not less than set forth in Table
720.1(1), except as modified in this section. The figures
shown shall be the net thickness of the protecting materials
and shall not include any hollowspace in back of the protection.

International Building Code 720.1.2

Unit masonry protection. Where required, metal
ties shall be embedded in bed joints of unit masonry for protection
of steel columns. Such ties shall be as set forth in
Table 720.1(1) or be equivalent thereto.

International Building Code 720.1.3

Reinforcement for cast-in-place concrete column
protection. Cast-in-place concrete protection for steel
columns shall be reinforced at the edges of such members
with wire ties of not less than 0.18 inch (4.6 mm) in diameter
wound spirally around the columns on a pitch of not more
than 8 inches (203 mm) or by equivalent reinforcement.

International Building Code 720.1.4

Plaster application. The finish coat is not required
for plaster protective coatings where they comply with the
design mix and thickness requirements of Tables 720.1(1),
720.1(2) and 720.1(3).

International Building Code 720.1.5

Bonded prestressed concrete tendons. For members
having a single tendon or more than one tendon
installed with equal concrete cover measured from the nearest
surface, the cover shall not be less than that set forth in
Table 720.1(1). For members having multiple tendons
installed with variable concrete cover, the average tendon
cover shall not be less than that set forth in Table 720.1(1),
provided:
1. The clearance from each tendon to the nearest
exposed surface is used to determine the average
cover.
2. In no case can the clear cover for individual tendons
be less than one-half of that set forth in Table
720.1(1). A minimum cover of 0.75 inch (19.1 mm)
for slabs and 1 inch (25 mm) for beams is required for
any aggregate concrete.
3. For the purpose of establishing a fire-resistance rating,
tendons having a clear covering less than that set
forth in Table 720.1(1) shall not contribute more than
50 percent of the required ultimate moment capacity
for members less than 350 square inches (0.226m2) in
cross-sectional area and 65 percent for larger members.
For structural design purposes, however, tendons
having a reduced cover are assumed to be fully
effective.