Document baYLje8qwkKv2KQd8ZD7L7d3y

HEATINC VENTILATING AIR CONDITIONING CUIDE 1941 Grooved seam r Double seam Standing seam Pittsburgh seam S s^P Bar Angle Angle S,'P connection.' bar slip Good Fair Heater, filter, and washer connections Poor 586 CHAPTER 31. AIR DUCT DESIGN Table 4. Recommended Sheet Metal Gages for Ducts3 u. s. Std. Gage 26 24 24 22 Round Diameter. Inches Up to 18 19 to 30 * 31 to 45 Maximum Side, Inches Up to 12 13 to 24 25 to 30 31 to 48 Rectangular Ducts Type of Joint Connections S or Drive Slips 5 or Drive Slips 5 or Drive Slips Bar or Drive Slips 20 46 to 60 49 to 60 1J4 in. Angle Bar Slips or 1 >n- Angle Connections 18 61 and up 61 to 90 1% in. Angle Connections .. 18 91 and up 2 in. Angle Connections Bracing None None 1 in. Angle 4 ft from Slips iyi in. Angle 4 ft on Centers 1 H in. Angle 2 ft 8 in. on Centers \H in. Angle 2 ft 8 in. on Centers 2 in. Angle 2 ft 8 in. on Centers ali flat sides are not cross-broken two gages heavier material should be used. Table 5. Weights of Sheet Metal Used for Duct Construction u. s. Std. Gage Black Sheets Approximate Thickness, In. Weight Per Square Foot Steel Iron Ounces Pounds Galvanized Sheets* Approximate . Thickness, In. Weight Per Square Foot Steel Iron Ounces Pounds 30 0.0123 0.0125 8 0.500 0.0163 0.0165 10.5 0.656 28 0.0153 0.0156 10 0.625 0.0193 0.0196 12.5 0.781 26 0.0184 0.0188 12 0.750 0.0224 0.0228 14.5 0.906 24 0.0245 0.0250 16 1.000 0.0285 0.0290 18.5 1.156 22 0.0306 0.0313 20 1.250 0.0346 0.0353 22.5 1.406 20 0.0368 0.0375 24 . 1.500 0.0408 0.0415 26.5 1.656 18 0.0490 0.0500 32 2.000 0.0530 0.0540 34.5 2.156 16 0.0613 0.0625 40 14 0.0766 0.0781 50 12 0.1072 0.1094 70 11 0.1225 0.1250 80 10 0.1379 0.1406 90 2.500 3.125 4.375 5.000 5.625 0.0653 0.0806 0.1112 0.1265 0.1419 0.0665 0.0821 0.1134 0.1290 0.1446 42.5 52.5 72.5 82.5 92.5 2.656 3.281 4.531 . 5.156 5.781 ^Galvanized sheets are gaged before galvanizing and are therefore approximately 0.004 in. thicker. Table 6. Weights and Thicknesses of Standard Copper Sheetsc _____________________________ Rolled to Weight_____________________________ Weight per Square Foot Ounces Pounds Thickness, Inches Decimal Equivalent Nearest Fraction Nearest Gage No. B. & S. Stubs U. S. Std. 10 0.625 0.0135 Hi 27 29 29 12 0.750 0.0162 Hi 26 27 28 14 0.875 0.0189 Hi 25 26 26 16 1.000 0.0216 Hi 23 24 25 18 1.125 0.0243 Hi 22 23 24 20 1.250 0.0270 Hi 21 22 23 24 1.500 0.0324 Hi 20 21 22 28 1.750 0.0378 Hi 32 2.000 0.0432 Hi 36 2.250 0.0486 Hi 40 2.500 0.0540 Hi 19 20 20 17 19 19 16 18 18 _ 15 17 17 44 2.750 0.0594 He 48 3.000 0.0648 He 56 3.500 0.0756 Hi 64 4.000 - - 0.0864 Hi 15 17 17 14 16 16 13 15 14 11 14 13 .Variations from these weights must be expected in practice. 587