722.5.1 Structural steel columns.
BC § 722.5.1
The fire-resistance ratings of structural steel columns shall be based on the size of the element and the type of protection provided in accordance with this section. Figure 722.5.1(1)Determination of the Heated Perimeter of Structural Steel Columns Figure 722.5.1(2)Gypsum-Protected Structural Steel Columns with Sheet Steel Column Covers For SI: 1 inch = 25.4 mm, 1 foot = 305 mm.
1.Structural steel column, either wide flange or tubular shapes.
2.Type X gypsum board or gypsum panel products in accordance with ASTM C 1177, C 1178, C 1278, C 1396 or C 1658. The total thickness of gypsum board or gypsum panel products calculated as h in Section 722.5.1.2 shall be applied vertically to an individual column using one of the following methods: 1. As a single layer with no horizontal joints.
3.As multiple layers with horizontal joints are staggered not less than 12 inches vertically between layers and not less than 8 feet vertically in any single layer. The total required thickness of gypsum board or gypsum panel products shall be determined on the basis of the specified fire-resistance rating and the weight-to-heated-perimeter ratio (W/D) of the column. For fire-resistance ratings of 2 hours or less, one of the required layers of gypsum board or gypsum panel product may be applied to the exterior of the sheet steel column covers with 1-inch long Type S screws spaced 1 inch from the wallboard edge and 8 inches on center. For such installations, 0.0149-inch minimum thickness galvanized steel corner beads with 1 1/2-inch legs shall be attached to the wallboard with Type S screws spaced 12 inches on center.
4.Galvanized 0.0149-inch minimum thickness steel corner beads with 1 1/2-inch legs attached to the gypsum board or gypsum panel products with 1-inch-long Type S screws spaced 12 inches on center.
5.No. 18 SWG steel tie wires spaced 24 inches on center.
6.Sheet metal angles with 2-inch legs fabricated from 0.0221-inch minimum thickness galvanized steel.
7.Type S screws, 1 inch long, shall be used for attaching the first layer of gypsum board or gypsum panel product to the steel studs and the third layer to the sheet metal angles at 24 inches on center. Type S screws 1 3/4-inch long shall be used for attaching the second layer of gypsum board or gypsum panel product to the steel studs and the fourth layer to the sheet metal angles at 12 inches on center. Type S screws 2 1/4 inches long shall be used for attaching the third layer of gypsum board or gypsum panel product to the steel studs at 12 inches on center. Figure 722.5.1(4)Fire Resistance of Structural Steel Columns Protected with Various Thicknesses of Type X Gypsum Wallboard a For SI: 1 inch = 25.4 mm, 1 pound per linear foot/inch = 0.059 kg/m/mm. a. The W/D ratios for typical wide flange columns are listed in Table 722.5.1(1). For other column shapes, the W/D ratios shall be determined in accordance with Section 722.5.1.1. Figure 722.5.1(5)Wide Flange Structural Steel Columns with Spray-Applied Fire-Resistant Materials Figure 722.5.1(6)Concrete Protected Structural Steel Columns a, b a. When the inside perimeter of the concrete protection is not square, L shall be taken as the average of L 1 and L 2 . When 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 a minimum 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). For SI: 1 inch = 25.4 mm. Figure 722.5.1(7)Concrete or Clay Masonry Protected Structural Steel Columns 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). Table 722.5.1(1)W/D Ratios for Steel Columns Structural ShapeContour ProfileBoxProfileStructural ShapeContour ProfileBoxProfileStructural ShapeContour ProfileBoxProfileStructural ShapeContour ProfileBoxProfileW14 × 2332.553.65W10 × 1121.812.57× 2112.323.35× 1001.642.33× 1932.143.09× 881.452.08× 1761.962.85× 771.281.85× 1591.782.60× 681.151.66× 1451.642.39× 601.011.48× 1321.562.25× 540.9221.34× 1201.422.06× 490.841.23× 1091.291.88× 450.8881.24× 991.181.72× 390.781.09× 901.081.58× 330.6610.93× 821.231.68× 741.121.53W8 × 671.371.94× 681.041.41× 581.201.71× 610.9281.28× 481.001.44× 530.9151.21× 400.8491.23× 480.8351.10× 350.7491.08× 430.7520.99× 310.6650.97× 280.6880.96W12 × 1902.503.51× 240.5910.83× 1702.263.20× 210.5770.77× 1522.042.90× 180.4990.67× 1361.862.63× 1201.652.36W6 × 250.6961.00× 1061.472.11× 200.5630.82× 961.341.93× 160.5830.78× 871.221.76× 150.4310.63× 791.111.61× 120.4480.60× 721.021.48× 90.3380.46× 650.9251.35× 580.9251.31W5 × 190.6440.93× 530.8551.20× 160.550.80× 500.9091.23× 450.8291.12W4 × 130.5560.79× 400.7341.00 For SI: 1 pound per linear foot per inch = 0.059 kg/m/mm. Table 722.5.1(2)Properties of Concrete PropertyNormal Weight ConcreteStructural Lightweight ConcreteThermal conductivity (k c )0.95 Btu/hr • ft • °F0.35 Btu/hr • ft • °FSpecific heat (c c )0.20 Btu/lb °F0.20 Btu/lb °FDensity (P c )145 lb/ft 3110 lb/ft 3Equilibrium (free) moisturecontent (m) by volume4%5% For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 lb/ft 3 = 16.0185 kg/m 3 , Btu/hr • ft • °F = 1.731 W/(m • K) Table 722.5.1(3)Thermal Conductivity of Concrete or Clay Masonry Units Density (dm) of Units (lb/ft3)Thermal Conductivity (K) of Units (Btu/hr • ft • °F)Concrete Masonry UnitsDensity (dm) of Units (lb/ft3)Thermal Conductivity (K) of Units (Btu/hr • ft • °F)Concrete Masonry Units800.207850.228900.252950.2781000.3081050.3401100.3761150.4161200.4591250.5081300.5611350.6201400.6851450.7581500.837Clay Masonry Units1201.251302.25 For SI: 1 pound per cubic foot = 16.0185 kg/m 3 , Btu/hr • ft • °F = 1.731 W/(m • K). Table 722.5.1(4)Weight-to-heated-perimeter Ratios (W/d) for Typical Wide Flange Beam and Girder Shapes Structural ShapeContour ProfileBoxProfileStructural ShapeContour ProfileBoxProfileStructural ShapeContour ProfileBoxProfileStructural ShapeContour ProfileBoxProfileW36 × 3002.503.33W24 × 680.9421.21× 2802.353.12× 620.9341.14× 2602.182.92× 550.8281.02× 2452.082.76× 2301.952.61W21 × 1471.872.60× 2101.962.45× 1321.682.35× 1941.812.28× 1221.572.19× 1821.722.15× 1111.432.01× 1701.602.01× 1011.301.84× 1601.511.90× 931.401.80× 1501.431.79× 831.261.62× 1351.291.63× 731.111.44× 681.041.35W33 × 2412.132.86W21 × 620.9521.23× 2211.972.64× 570.9521.17× 2011.792.42× 500.8381.04× 1521.531.94× 440.7460.92× 1411.431.80× 1301.321.67W18 × 1191.722.42× 1181.211.53× 1061.552.18× 971.422.01W30 × 2112.012.74× 861.271.80× 1911.852.50× 761.131.60× 1731.662.28× 711.221.59× 1321.471.85× 651.131.47× 1241.391.75× 601.041.36× 1161.301.65× 550.9631.26× 1081.211.54× 500.881.15× 991.121.42× 460.8781.09× 400.7680.96W27 × 1781.872.55× 350.6720.85× 1611.702.33× 1461.552.12W16 × 1001.592.25× 1141.391.76× 891.432.03× 1021.241.59× 771.251.78× 941.151.47× 671.091.56× 841.031.33× 571.091.43× 500.9621.26× 450.8701.15W24 × 1621.882.57× 400.7801.03× 1461.702.34× 360.7020.93× 1311.542.12× 310.6610.83× 1171.381.91× 260.5580.70× 1041.241.71× 941.281.63W14 × 1321.893.00x 841.151.47x 1201.712.75× 761.051.34× 1091.572.52W14 × 991.432.31W10 × 300.8061.12× 901.312.11× 261.7080.98× 821.452.12× 220.6060.84× 741.321.93× 190.6070.78× 681.221.78× 170.5430.70× 611.101.61× 150.4840.63× 531.061.48× 120.3920.51× 480.9701.35W14 × 430.8741.22W8 × 671.652.55× 380.8091.09× 581.442.26× 340.7250.98× 481.211.91× 300.6440.87× 401.031.63× 260.6280.79× 350.9071.44× 220.5340.68× 310.8031.29× 280.8191.24W12 × 871.472.34× 240.7041.07× 791.342.14× 210.6750.96× 721.231.97× 180.5830.84× 651.111.79× 150.5510.74× 581.101.69× 130.4830.65× 531.021.55× 100.3750.51× 501.061.54× 450.9741.40W6 × 250.8391.33× 400.8601.25× 200.6781.09× 350.8101.11× 160.6840.96× 300.6990.96× 150.5210.83× 260.6120.84× 120.5260.75× 220.6230.77× 90.3980.57× 190.5400.67× 160.4570.57W5 × 190.7761.24× 140.4050.50× 160.6641.07W10 × 1122.173.38W4 × 130.6701.05× 1001.973.07× 881.742.75× 771.542.45× 681.382.20× 601.221.97× 541.111.79× 491.011.64× 451.061.59× 390.941.40× 330.771.20 For SI: Pounds per linear foot per inch = 0.059 kg/m/mm. Table 722.5.1(5)Fire Resistance of Concrete Masonry Protected Steel Columns Column SizeConcrete Masonry Density Pounds per Cubic FootMinimum Required Equivalent Thickness for Fire-Resistance Rating of Concrete Masonry Protection Assembly, Te (inches)Column SizeConcrete Masonry Density Pounds per Cubic FootMinimum Required Equivalent Thickness for Fire-Resistance Rating of Concrete Masonry Protection Assembly, Te (Inches)1 hour2 hours3 hours4 hours1 hour2 hours3 hours4 hoursColumn SizeConcrete Masonry Density Pounds per Cubic FootMinimum Required Equivalent Thickness for Fire-Resistance Rating of Concrete Masonry Protection Assembly, Te (inches)Column SizeConcrete Masonry Density Pounds per Cubic FootMinimum Required Equivalent Thickness for Fire-Resistance Rating of Concrete Masonry Protection Assembly, Te (Inches)1 hour2 hours3 hours4 hours1 hour2 hours3 hours4 hoursW14 × 82800.741.612.363.04W10 × 68800.721.582.333.011000.891.852.673.401000.871.832.653.381100.961.972.813.571100.941.952.793.551201.032.082.953.731201.012.062.943.72W14 × 68800.831.702.453.13W10 × 54800.881.762.533.211000.991.952.763.491001.042.012.833.571101.062.062.913.661101.112.122.983.731201.142.183.053.821201.192.243.123.90W14 × 53800.911.812.583.27W10 × 45800.921.832.603.301001.072.052.883.621001.082.072.903.641101.152.173.023.781101.162.183.043.801201.222.283.163.941201.232.293.183.96W14 × 43801.011.932.713.41W10 × 33801.062.002.793.491001.172.173.003.741001.222.233.073.811101.252.283.143.901101.302.343.203.961201.322.383.274.051201.372.443.334.12W12 × 72800.811.662.413.09W8 × 40800.941.852.633.331000.911.882.703.431001.102.102.933.671100.991.992.843.601101.182.213.073.831201.062.102.983.761201.252.323.203.99W12 × 58800.881.762.523.21W8 × 31801.062.002.783.491001.042.012.833.561001.222.233.073.811101.112.122.973.731101.292.333.203.971201.192.233.113.891201.362.443.334.12W12 × 50800.911.812.583.27W8 × 24801.142.092.893.591001.072.052.883.621001.292.313.163.901101.152.173.023.781101.362.423.284.051201.222.283.163.941201.432.523.414.20W12 × 40801.011.942.723.41W8 × 18801.222.203.013.721001.172.173.013.751001.362.403.254.011101.252.283.143.901101.422.503.374.141201.322.393.274.061201.482.593.494.284 × 4 × 1/2wall thickness800.931.902.713.434 double extra strong 0.674 wall thickness800.801.752.563.281001.082.132.993.761000.951.992.853.621101.162.243.133.911101.022.102.993.781201.222.343.264.061201.092.203.123.934 × 4 × 3/8wall thickness801.052.032.843.574 extra strong 0.337 wall thickness801.122.112.933.651001.202.253.113.881001.262.323.193.951101.272.353.244.021101.332.423.314.091201.342.453.374.171201.402.523.434.234 × 4 × 1/4wall thickness801.212.203.013.734 standard 0.237 wall thickness801.262.253.073.791001.352.403.264.021001.402.453.314.071101.412.503.384.161101.462.553.434.211201.482.593.504.301201.532.643.544.346 × 6 × 1/2wall thickness800.821.752.543.255 double extra strong 0.750 wall thickness800.701.612.403.121000.981.992.843.591000.851.862.713.471101.052.102.983.751100.911.972.853.631201.122.213.113.911200.982.022.993.796 × 6 × 3/8wall thickness800.961.912.713.425 extra strong 0.375 wall thickness801.042.012.833.541001.122.143.003.751001.192.233.093.851101.192.253.133.901101.262.343.224.001201.262.353.264.051201.322.443.344.146 × 6 × 1/4wall thickness801.142.112.923.635 standard 0.258 wall thickness801.202.193.003.721001.292.323.183.931001.342.393.254.001101.362.433.304.081101.412.493.374.141201.422.523.434.221201.472.583.494.288 × 8 × 1/2wall thickness800.771.662.443.136 double extra strong 0.864 wall thickness800.591.462.232.921000.921.912.753.491000.731.712.543.291101.002.022.893.661100.801.822.693.471201.072.143.033.821200.861.932.833.638 × 8 × 3/8wall thickness800.911.842.633.336 extra strong 0.432 wall thickness800.941.902.703.421001.072.082.923.671001.102.132.983.741101.142.193.063.831101.172.233.113.891201.212.293.193.981201.242.343.244.048 × 8 × 1/4wall thickness801.102.062.863.576 standard 0.280 wall thickness801.142.122.933.641001.252.283.133.871001.292.333.193.941101.322.383.254.021101.362.433.314.081201.392.483.384.171201.422.533.434.22 For SI: 1 inch = 25.4 mm, 1 pound per cubic feet = 16.02 kg/m 3 . Note: Tabulated values assume 1-inch air gap between masonry and steel section. Table 722.5.1(6)Fire Resistance of Clay Masonry Protected Steel Columns Column SizeClay Masonry Density, Pounds per Cubic FootMinimum Required Equivalent Thickness For Fire-Resistance Rating of Clay Masonry Protection Assembly, Te (inches)Column SizeClay Masonry Density, Pounds per Cubic FootMinimum Required Equivalent Thickness For Fire-Resistance Rating of Clay Masonry Protection Assembly, Te (inches)1 hour2 hours3 hours4 hours1 hour2 hours3 hours4 hoursW14 × 821201.232.423.414.29W10 × 681201.272.463.264.351301.402.703.784.741301.442.753.834.80W14 × 681201.342.543.544.43W10 × 541201.402.613.624.511301.512.823.914.871301.582.893.984.95W14 × 531201.432.653.654.54W10 × 451201.442.663.674.571301.612.934.024.981301.622.954.045.01W14 × 431201.542.763.774.66W10 × 331201.592.823.844.731301.723.044.135.091301.773.104.205.13W12 × 721201.322.523.514.40W8 × 401201.472.703.714.611301.502.803.884.841301.652.984.085.04W12 × 581201.402.613.614.50W8 × 311201.592.823.844.731301.572.893.984.941301.773.104.205.17W12 × 501201.432.653.664.55W8 × 241201.662.903.924.821301.612.934.024.991301.843.184.285.25W12 × 401201.542.773.784.67W8 × 181201.753.004.014.911301.723.054.145.101301.933.274.375.34Nominal tube size (inches)Clay masonry density, pounds per cubic footMinimum required equivalent thickness for fire-resistance rating of clay.Masonry protection assembly Te, (inches)Nominal tube size (inches)Clay masonry density, pounds per cubic footMinimum required equivalent thickness for fire-resistance rating of clay.Masonry protection assembly Te, (inches)1-hour2-hour3-hour4-hour1-hour2-hour3-hour4-hour4 × 4 × 1/2wall thickness1201.442.723.764.684 double extra strong 0.674 wall thickness1201.262.553.604.521301.623.004.125.111301.422.823.964.954 × 4 × 3/8wall thickness1201.562.843.884.784 extra strong 0.337 wall thickness1201.602.893.924.831301.743.124.235.211301.773.164.285.254 × 4 × 1/4wall thickness1201.722.994.024.924 standard 0.237 wall thickness1201.743.024.054.951301.893.264.375.341301.923.294.405.376 × 6 × 1/2wall thickness1201.332.583.624.525 double extra strong 0.750 wall thickness1201.172.443.484.401301.502.863.984.961301.332.723.844.836 × 6 × 3/8wall thickness1201.482.743.764.675 extra strong 0.375 wall thickness1201.552.823.854.761301.653.014.135.101301.723.094.215.186 × 6 × 1/4wall thickness1201.662.913.944.845 standard 0.258 wall thickness1201.712.974.004.901301.833.194.305.271301.883.244.355.328 × 8 × 1/2wall thickness1201.272.503.524.426 double extra strong 0.864 wall thickness1201.042.283.324.231301.442.783.894.861301.192.603.684.678 × 8 × 3/8wall thickness1201.432.673.694.596 extra strong 0.432 wall thickness1201.452.713.754.651301.602.954.055.021301.622.994.105.088 × 8 × 1/4wall thickness1201.622.873.894.786 standard 0.280 wall thickness1201.652.913.944.841301.793.144.245.211301.823.194.305.27 For SI: 1 inch = 25.4 mm, 1 pound per cubic foot = 16.02 kg/m 3 . Table 722.5.1(7)Minimum Cover (inch) for Steel Columns Encased in Normal-Weight Concrete aFigure 722.5.1(6)(c) Structural ShapeFire-Resistance Rating (hours)11 1/2234Structural ShapeFire-Resistance Rating (hours)11 1/2234W14 × 2331111 1/22× 1762 1/2× 1322× 901 1/2× 61× 481 1/22 1/2× 43W12 × 15211122 1/2× 96× 651 1/21 1/23× 502 1/2× 40W10 × 8811 1/21 1/223× 4912 1/2× 45× 393 1/2× 332W8 × 67111 1/22 1/23× 58× 481 1/23 1/2× 3123× 21× 184W6 × 2511 1/2233 1/2× 2022 1/24× 163 1/2× 151 1/2× 9 For SI: 1 inch = 25.4 mm. a. The tabulated thicknesses are based upon the assumed properties of normal-weight concrete given in Table 722.5.1(2). Table 722.5.1(8)Minimum Cover (inch) for Steel Columns Encased in Structural Lightweight Concrete aFigure 722.5.1(6)(c) Structural ShapeFire-Resistance Rating (hours)11 1/2234Structural ShapeFire-Resistance Rating (hours)11 1/2234W14 × 23311111 1/2× 1931 1/2× 742× 612 1/2× 4311 /22W12 × 651111 1/22× 5322 1/2× 401 1/2W10 × 1121111 1/22× 88× 6022 1/2× 331 1/2W8 × 35111 1/222 1/2× 283× 242 1/2× 181 1/2 For SI: 1 inch = 25.4 mm. a. The tabulated thicknesses are based upon the assumed properties of structural lightweight concrete given in Table 722.5.1(2). Table 722.5.1(9)Minimum Cover (inch) for Steel Columns in Normal-Weight Precast Covers aFigure 722.5.1(6)(a) Structural ShapeFire-Resistance Rating (hours)11 1/2234Structural ShapeFire-Resistance Rating (hours)11 1/2234W14 × 2331 1/21 1/21 1/22 1/23× 2113 1/2× 1762× 1453× 10922 1/2× 994× 613 1/2× 434 1/2W12 × 1901 1/21 1/21 1/22 1/23 1/2× 1522× 12034× 96× 8722 1/23 1/2× 584 1/2× 40W10 × 1121 1/21 1/2233 1/2× 884× 7722 1/2× 543 1/2× 334 1/2W8 × 671 1/21 1/2234× 5822 1/23 1/2× 48× 284 1/2× 212 1/23× 184W6 × 251 1/222 1/23 1/24 1/2× 202 1/23× 164× 122× 95 For SI: 1 inch = 25.4 mm. a. The tabulated thicknesses are based upon the assumed properties of normal-weight concrete given in Table 722.5.1(2). Table 722.5.1(10)Minimum Cover (inch) for Steel Columns in Structural Lightweight Precast Covers aFigure 722.5.1(6)(a) Structural ShapeFire-Resistance Rating (hours)11 1/2234Structural ShapeFire-Resistance Rating (hours)11 1/2234W14 × 2331 1/21 1/21 1/222 1/2× 1763× 1452 1/2× 132× 109× 992× 683 1/2× 433W12 × 1901 1/21 1/21 1/222 1/2× 152× 1363× 1062 1/2× 963 1/2× 87× 652× 403W10 × 1121 1/21 1/21 1/223× 1002 1/2× 88× 7723 1/2× 60× 393× 332W8 × 671 1/21 1/21 1/22 1/23× 48233 1/2× 35× 282× 182 1/24W6 × 251 1/22233 1/2× 152 1/24× 93 1/2 For SI: 1 inch = 25.4 mm. a. The tabulated thicknesses are based upon the assumed properties of structural lightweight concrete given in Table 722.5.1(2). (Am. L.L. 2023/077, 6/11/2023, eff. 6/11/2023) Editor's note: For related unconsolidated provisions, see Appendix A at L.L. 2023/077.
