Fire Resistance Rating Unfilled Cmu Standard Calculation Methods Structural

At wind speeds of 110 miles per hour (mph), all the coated walls resisted water penetration, but the uncoated wall failed early in the testing at lower wind speeds (62 mph).

A brick wall’s fire resistance rating can be calculated.

Fire Resistance and Smoke Protection – Fire Resistance Rating Unfilled Cmu Masonry

At wind speeds exceeding 155 mph, traditional ½ inch stucco provided excellent resistance to moisture penetration. The ½-inch coating allowed much less water than the skim coat to pass through the wall over the test duration. The thickness of panels with tapered cross sections shall be that determined at a distance 2t or 6 inches (152 mm), whichever is less, from the point of minimum thickness, where t is the minimum thickness.

Equivalent thickness of the panel calculated as the net cross-sectional area of the panel divided by the width, in which the maximum thickness used in the calculation shall not exceed 2t.

Dry unit weight of 35 pcf or less and consisting of cellular, perlite or vermiculite concrete. Rn0.59 value for two 1/2″ to 31/2″ airspaces is 6.7. The fire-resistance rating for this thickness exceeds 4 hours. Joints between precast concrete wall panels that are not insulated as required by this section shall be considered as openings in walls. Figure 722.2.1.3.1 shows thicknesses of ceramic fiber blankets to be used to insulate joints between precast concrete wall panels for various panel thicknesses and for joint widths of 3/8 inch (9.5 mm) and 1 inch (25 mm) for fire-resistance ratings of 1 hour to 4 hours.

Other tested and labeled materials are acceptable in place of ceramic fiber blankets. Where finishes applied to one or both sides of a concrete wall contribute to the fire-resistance rating, the concrete alone shall provide not less than onehalf of the total required fire-resistance rating.

Sections 722.2.2.2 and 722.2.2.3, respectively. For hollow-core prestressed concrete slabs in which the cores are of constant cross section throughout the length, the equivalent thickness shall be permitted to be obtained by dividing the net cross-sectional area of the slab including grout in the joints, by its width.

Equivalent thickness of the slab calculated as the net area of the slab divided by the width, in which the maximum thickness used in the calculation shall not exceed 2t.

Joints between adjacent precast concrete slabs need not be considered in calculating the slab thickness provided that a concrete topping not less than 1 inch (25 mm) thick is used.

For beam widths between the tabulated values, the minimum cover thickness can be determined by direct interpolation. The cover for an individual reinforcing bar is the minimum thickness of concrete between the surface of the bar and the fire-exposed surface of the beam.

For beam widths between 8 inches and 12 inches, minimum cover thickness can be determined by direct interpolation. Not practical for 8-inch-wide beam but shown for purposes of interpolation. The cross-sectional area of a stem is permitted to include a portion of the area in the flange, provided the width of the flange used in the calculation does not exceed three times the average width of the stem.

These tables are applicable to slabs that are either cast in place or precast. Table 722.2.3(4) apply to beams 8 inches (203 mm) or greater in width. Table 722.2.3(5) apply to beams or stems of any width, provided the cross-section area is not less than 40 square inches (25 806 mm2).

Table 722.2.3(4) or 722.2.3(5), it is permitted to use the smaller value. The concrete cover for an individual tendon is the minimum thickness of concrete between the surface of the tendon and the fire-exposed surface of the beam, except that for ungrouted ducts, the assumed cover thickness is the minimum thickness of concrete between the surface of the duct and the fire-exposed surface of the beam.

For corner tendons (tendons equal distance from the bottom and side), the minimum cover used in the calculation shall be one-half the actual value.

The minimum dimension is permitted to be reduced to 8 inches for rectangular columns with two parallel sides not less than 36 inches in length.

The minimum dimension is permitted to be reduced to 10 inches for rectangular columns with two parallel sides not less than 36 inches in length.

Standard Calculation Methods for Structural Fire Protection

The free ends of circular ties shall terminate with a 90-degree (1.6 rad) standard tie hook. The free ends of spirals, including at lap splices, shall terminate with a 90-degree (1.6 rad) standard tie hook. The equivalent thickness of concrete masonry construction shall be determined in accordance with the provisions of this section. Values between those shown in the table can be determined by direct interpolation. For a wall having no finish on one side or having different types or thicknesses of finish on each side, the calculation procedures of this section shall be performed twice, assuming either side of the wall to be the fire-exposed side.