Document rpzrmK3dg6ZOoe4qdB71mRyOa

American Society of Heating and Ventilating Engineers Guide, 1928 Chimneys recommended for larger boilers 15 to 250 hp. are propor tioned in accordance with the report made by a joint Committee of the American Boiler Manufacturers Association and Stoker Manufacturers Association and approved by these organizations. The sizes are given in Table 2. Table 2. Height of Stack for Average Installations (Sea Level) Forced Draft Stokers 100 0.15 0.18 0.10 0.43 80 150 0.15 0.4 0.10 0.65 112 200 0.15 0.65 0.10 0.90 145 250 0.15 0.9 0.10 1.15 178 300 . 0.15 1.20 0.10 1.45 220 Diameter of Chimney in Inches for Horizontal Return Tubular Boilers Nominal H. P. 15 20 25 30 35 40 50 60 75 90 100 115 125 150 175 200 210 225 250 100% Rating 13 14 16 17 18 19 20 21 23 25 26 27 28 30 32 33 34 35 36 150% Rating 14 16 18 19 20 21 23 24 26 28 29 31 32 34 36 38 38 40 41 200% Rating 17 18 20 21 22 23 25 27 29 31 33 34 35 38 40 43 44 45 47 Height of Stack in Feet--For Sea Level and 60 deg. fahr. Outside Temp. Assumed Fric tion Loss in Stack 0.1 in. per 100 ft. Draft at 100% Base of Stack Rating 150% Rating 200% Rating 0.12 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55 0.60 0.65 ____ ____ ___ 21 22 25 26 28 30 35 37 41 43 46 51 52 56 61 60 65 71 69 74 81 78 84 91 86 93 101 95 102 111 104 112 122 112 121 132 ___ :__ ___ ___ . ____ _______ -- ___ Data on Which Tables are Based Rating............ Efficiency___ CO,................ 100% 65% 8% 150% 65% 9% 200% 63% 10% Stack Temp, deg. fahr................. 450 500 550 Lbs. of Gas................ . 85 77- 73 Average Friction Loss Through Boilers Per Cent Rating............. 100 150 200 250 Loss Ins., Water............. 0.1to0.3 0.2to0.6 0.3 to 0.9 0.5 to 1.4 300 0.7tol.9 ", Friction loss through boiler varies according to construction. For Furnace Draft.--Allow 0.15 for forced draft. For Natural Draft 0.35 in. or higher should be used depending upon rate of combustion and fuel used. For Breeching Friction Loss.--Allow 0.05 in. for each right angle bend and 0.1 in. per 100 ft. of length. Cross sectional area should be 20 per cent larger than that of stack. 162 Chapter VII--Steam and Hot Water Heating Boilers Height of Stack in Feet For Sea Level and 60 deg. fahr. Outside Temperature and 0.1 in. Friction Loss per 100 ft. Total Draft Required In. for Furnace Boiler and Breeching Per,Cent of Boiler Rating 100 150 200 250 300 0.3 56 0.4 74 69 0.5 93 86 81 0.6 111 103 97 0.7 130 120 113 108 0.8 148 138 129 123 0.9 155 145 139 132 1.0 172 161 154 147 1.1 190 177 170 162 1.2 194 185 176 1.3 209 200 191 1.4 226 2i6 206 1.5 231 221 1.6 236 1.8 265 Assumed Flue Gas Temp................... 500 550 600 650 700 Correction for Altitude Height Above Sea Level (Ft.) Ratio Increase in Diameter 0 1,000 2,000 4,000 6,000 8,000 10,000 1.000 1.015 1.030 . 1.063 1.096 1.130 1.165 Ratio Increase in Height 1.000 1.046 1.097 1.205 1.321 1.456 1.612 The principal factors which affect the loss of . draft through the fuel bed according to J. G. Mingle,1 are: 1. Character of fuel burned, 2. Amount of fuel burned per square foot of grate surface per hour, or the rate of com bustion. - The loss of draft through the boiler is affected mainly by: 1. Type and size of boiler, 2. Rate of operation. The required height of a chimney is affected by the following: 1. Character of fuel burned, 2. Rate of combustion, 1 Draft and Capacity of Chimneys.