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FIRE AND SMOKE PROTECTION FEATURES
h h 2
L * * L 2 d
L h L 1 h 1 b f As
(a) (b) (c)
PRECAST CONCRETE CONCRETE
CONCRETE ENCASED ENCASED
COLUMN STRUCTURAL WIDE-FLANGE
COVERS TUBE SHAPE
FIGURE 722.5.1(6)
CONCRETE PROTECTED STRUCTURAL STEEL COLUMNS a, b
a. Where the inside perimeter of the concrete protection is not square, L shall be taken as the average of L 1 and L 2 . Where the thickness of concrete cover is not
constant, h shall be taken as the average of h 1 and h 2 .
b. Joints shall be protected with not less than a 1-inch thickness of ceramic fiber blanket but in no case less than one-half the thickness of the column cover (see
Section 722.2.1.3).
D=2(w+d)+2(w-t web ) D = d D = 2w + 2d
w d w
0.25p
d t d
web
0.25p
W SHAPE COLUMN STEEL PIPE COLUMN STRUCTURAL TUBE COLUMN
FIGURE 722.5.1(7)
CONCRETE OR CLAY MASONRY PROTECTED STRUCTURAL STEEL COLUMNS
For SI: 1 inch = 25.4 mm.
d = Depth of a wide flange column, outside diameter of pipe column, or outside dimension of structural tubing column (inches).
t web = Thickness of web of wide flange column (inches).
w = Width of flange of wide flange column (inches).
722.5.1.2.1 Attachment. The gypsum board or gyp- shall be the same as the thickness determined for a
sum panel products shall be supported as illustrated W14 × 233 wide flange shape.
in either Figure 722.5.1(2) for fire-resistance ratings 722.5.1.3 Sprayed fire-resistant materials. The fire
of 4 hours or less, or Figure 722.5.1(3) for fire-resis- resistance of wide-flange structural steel columns pro-
tance ratings of 3 hours or less. tected with sprayed fire-resistant materials, as illus-
722.5.1.2.2 Gypsum wallboard equivalent to con- trated in Figure 722.5.1(5), shall be permitted to be
crete. The determination of the fire resistance of determin fr th following expression:
structural steel columns from Figure 722.5.1(4) is
2
1
permitted for various thicknesses of gypsum wall- R = [C (W/D) + C ]h (Equation 7-13)
board as a function of the weight-to-heated-perime- where:
ter ratio (W/D) of the column. For structural steel R = Fire resistance (minutes).
columns with weight-to-heated-perimeter ratios (W/D) h = Thickness of sprayed fire-resistant material
greater than 3.65, the thickness of gypsum wall- (inches).
board required for specified fire-resistance ratings
2018 INTERNATIONAL BUILDING CODE ® 195
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