The weight of steam required to heat a given quantity of water from a certain temperature to boiling point can be found by the following rule:

### Rule

Multiply the number of pounds of water to be heated by the number of degrees temperature the water is to be raised, and divide the product by the total heat of steam at the pressure it is to be used, less the sensible heat at atmospheric pressure. This may be expressed by the formula:

S= (w h)/ (L-l) In which w=weight of steam in pounds w=pounds of water to be heated h=degrees Fahr. water is to be heated L=total heat of steam at pressure used l=sensible heat at atmospheric pressure

Example-How many pounds of steam at 70 pounds pressure will be required to heat 7,500 pounds of water from 48 degrees Fahr. to boiling point?

### Solution

{7500 (212-8)}/ (1174-180) = 1237 pounds of steam. Answer.

An empirical rule that is sufficiently approximate for most purposes is to allow 1 pound of steam for 6 pounds of water to be heated. Taking the above example then 7500/6=1250 pounds of steam. Answer.

The temperature of steam at different pressures can be found in Table LIII. To use this table, add 14.7 to the reading of the gauge to get absolute pressure; the quantities desired will be opposite this figure.

Usually 15 pounds added to the gauge pressure to get the absolute pressure will be sufficiently accurate for all ordinary purposes.

## Table LII - Properties Of Saturated Steam

 Absolute Pressure Temperature Degrees Fahr. Heat Units above 32 Degrees Fahr. Contained in 1 Pound of Steam Weight1 CubicFoot inPounds Volume of 1 Pound inCubicFeet In Water Latent Heat Total Heat 14.7 212.0 180.9 965.7 1146.6 .0379 26.37 15 213.1 181.6 965.3 .9 .0387 25.85 16 216.3 184.9 963.0 1147.9 .0411 24.33 17 219.5 188.1 960.8 1148.9 .0435 22.98 18 222.4 191.1 958.7 1149.8 .0459 21.78 19 225.3 193.9 956.7 1150.6 .0483 20.70

## Table LIII - Continued

 Absolute Pressure Temperature Degrees Fahr. Heat Units above 32 Degrees Fahr. Contained in 1 Pound of Steam Weight1 CubicFoot inPounds Volume of 1 Pound inCubicFeet In Water Latent Heat Total Heat 20 228.0 196.7 954.8 1151.5 .0507 19.73 21 230.6 199.3 953.0 1152.3 .0531 18.84 22 233.1 201.8 951.2 1153.0 .0554 18.04 23 235.5 204.3 949.5 .8 .0578 17.30 24 237.8 206.6 947.9 1154.5 .0602 16.62 25 240.1 208.9 946.3 1155.2 .0625 16.00 26 242.2 211.1 944.7 .8 .0649 15.42 27 244.3 213.2 943.3 1156.5 .0672 14.88 28 246.4 215.3 941.8 1157.1 .0695 14.38 29 248.4 217.3 940.4 .7 .0719 13.91 30 250.3 219.3 939.0 1158.3 .0742 13.48 31 252.2 221.2 937.7 .9 .0765 13.07 32 254.0 223.0 936.4 1159.4 .0788 12.68 33 255.8 224.8 935.1 .9 .0812 12.32 34 257.5 226.6 933.9 1160.5 .0835 11.98 35 259.2 228.3 932.7 1161.0 .0858 11.66 36 260.9 230.0 931.5 .5 .0881 11.36 37 262.5 231.6 930.4 1162.0 .0904 11.07 38 264.1 233.3 929.2 .5 .0927 10.79 39 265.6 234.8 928.1 .9 .0949 10.53 40 267.2 236.4 927.0 1163.4 .0972 10.28 41 268.7 237.9 926.0 .9 .0995 10.05 42 270.1 239.4 924.9 1164.3 .1018 9.83 43 271.6 240.8 923.9 .7 .1041 9.61 44 273.0 242.3 922.9 1165.2 .1063 9.40 45 274.3 243.7 921.9 .6 .1086 9.21 46 275.7 245.1 920.9 1166.0 .1109 9.02 47 277.0 246.4 920.0 .4 .1131 8.84 48 278.3 247.7 919.1 .8 .1154 8.67 49 279.6 249.1 918.1 1167.2 .1177 8.50 50 280.9 250.3 917.3 .6 .1199 8.34 51 282.2 251.6 916.4 1168.0 .1222 8.19 52 283.4 252.9 915.5 .4 .1244 8.04 53 284.6 254.1 914.6 .7 .1267 7.89 54 285.8 255.3 913.8 1169.1 .1289 7.76 55 287.0 256.5 912.9 .4 .1312 7.62 56 288.1 257.7 912.1 1169.8 .1334 7.50 57 289.3 258.9 911.3 1170.2 .1357 7.37 58 290.4 260.0 910.5 .5 .1379 7.25 59 291.5 261.1 909.7 .8 .1401 7.14 60 292.6 262.3 908.9 1171.2 .1424 7.02 61 293.7 263.3 908.2 .5 .1446 6.92 62 294.7 264.4 907.4 .8 .1468 6.81 63 295.8 265.5 906.6 1172.1 .1491 6.71 64 296.8 266.6 905.9 .5 .1513 6.61 65 297.8 267.6 905.2 .8 .1535 6.52

## Table LIII - Continued

 Absolute Pressure Temperature Degrees Fahr. Heat Units above 32 DegreesFahr.Contained in 1 Pound of Steam Weight of1 CubicFoot in Pounds Volume of 1 Pound inCubicFeet In Water Latent Heat Total Heat 66 298.8 268.7 904.4 1173.1 .1557 6.42 67 299.8 269.7 903.7 .4 .1579 6.33 68 300.8 270.7 903.0 .7 .1602 6.24 69 301.8 271.7 902.3 1174.0 .1624 6.16 70 302.8 272.7 901.6 .3 .1646 6.08 71 303.7 273.6 901.0 .6 .1668 6.00 72 304.7 274.6 900.3 .9 .1690 5.92 73 305.6 275.6 899.6 1175.2 .1712 5.84 74 306.5 276.5 898.9 .4 .1734 5.77 75 307.4 277.4 898.3 .7 .1756 5.69 76 308.3 278.4 897.6 1176.0 .1778 5.62 77 309.2 279.3 897.0 .3 .1800 5.56 78 310.1 280.2 896.3 .5 .1822 5.49 79 311.0 281.1 895.7 .8 .1844 5.42 80 311.9 282.0 895.1 1177.1 .1866 5.36 81 312.7 282.8 894.5 .3 .1888 5.30 82 313.6 283.7 893.9 .6 .1910 5.24 83 314.4 284.5 893.3 .8 .1932 5.18 84 315.3 285.4 892.7 1178.1 .1954 5.12 85 316.1 286.2 892.1 .3 .1976 5.06 86 316.9 287.1 891.5 .6 .1998 5.01 87 317.7 287.9 890.9 .8 .2020 4.95 88 318.5 288.8 890.3 1179.1 .2042 4.90 89 319.3 289.6 889.7 .3 .2063 4.85 90 320.1 290.4 889.2 .6 .2085 4.80 91 320.9 291.2 888.6 .8 .2107 4.75 92 321.7 291.9 888.1 1180.0 .2129 4.70 93 322.4 292.8 887.5 .3 .2151 4.65 94 323.2 293.5 887.0 .5 .2173 4.60 95 323.9 294.3 886.4 .7 .2194 4.56 96 324.7 295.1 885.9 1181.0 .2216 4.51 97 325.4 295.8 885.4 .2 .2238 4.47 98 326.2 296.6 884.8 .4 .2260 4.43 99 326.9 297.3 884.3 .6 .2281 4.38 100 327.6 298.1 883.8 .9 .2303 4.34 101 328.3 298.8 883.3 1182.1 .2325 4.30 102 329.1 296.6 882.7 .3 .2346 4.26 103 329.8 300.3 882.2 .5 .2368 4.22 104 330.5 301.0 881.7 .7 .2390 4.19 105 331.2 301.7 881.2 .9 .2411 4.15 106 331.9 302.4 880.7 1183.1 .2433 4.11 107 332.6 303.2 880.2 .4 .2455 4.07 108 333.2 303.9 879.7 1183.6 .2476 4.04 109 333.9 304.6 879.2 .8 .2498 4.00 110 334.6 305.3 878.7 1184.0 .2519 3.97 111 335.3 305.9 878.3 .2 .2541 3.94

## Table LIII - Continued

 Absolute Pressure Temperature Degeees Fahr. Heat Units above 32 DegreesFahr.Contained in 1 Pound of Steam Weight of1 CubicFoot in Pounds Volume of1 Pound inCubicFeet In Water Latent Heat Total Heat 112 335.9 306.6 877.8 1184.4 .2563 3.90 113 336.6 307.3 877.3 .6 .2584 3.87 114 337.2 308.0 876.8 .8 .2606 3.84 115 337.9 308.6 876.4 1185.0 .2627 3.81 116 338.5 309.3 875.9 .2 .2649 3.78 117 339.2 310.0 875.4 .4 .2670 3.75 118 339.8 310.6 875.0 .6 .2692 3.72 119 340.4 311.3 874.5 .8 .2713 3.69 120 341.1 311.9 874.1 1186.0 .2735 3.66 121 341.7 312.5 873.6 .1 .2757 3.63 122 342.3 313.1 873.2 .3 .2778 3.60 123 342.9 313.8 872.7 .5 .2799 3.57 124 343.5 314.4 872.3 .7 .2821 3.55 125 344.1 315.1 871.8 .9 .2842 3.52 126 344.7 315.7 871.4 1187.1 .2864 3.49 127 345.3 316.3 871.0 .3 .2885 3.47 128 345.9 316.9 870.5 .4 .2907 3.44 129 346.5 317.5 870.1 .6 .2928 3.42 130 347.1 318.1 869.7 .8 .2950 3.39 131 347.7 318.7 869.3 1188.0 .2971 3.37 132 348.3 319.3 868.9 .2 .2992 3.34 133 348.9 319.9 868.4 .3 .3014 3.32 134 349.4 320.5 868.0 .5 .3035 3.30 135 350.0 321.1 867.6 .7 .3057 3.27 136 350.6 321.7 867.2 .9 .3078 3.25 137 351.1 322.3 866.8 1189.1 .3099 3.23 138 351.7 322.8 866.4 .2 .3121 3.20 139 140 352.3 352.8 323.4 324.0 866.0 865.6 .4 .6 .3142 .3163 3.18 3.16 141 353.4 324.6 865.1 .7 .3185 3.14 142 353.9 325.1 864.8 .9 .3206 3.12 143 354.5 325.7 864.4 1190.1 .3227 3.10 144 355.0 326.2 864.0 .2 .3249 3.08 145 355.6 326.8 863.6 .4 .3270 3.06 146 356.1 327.4 863.2 .6 .3291 3.04 147 356.6 327.9 862.8 .7 .3313 3.02 148 357.2 328.5 862.4 .9 .3334 3.00 149 357.7 329.0 862.0 1191.0 .3355 2.98 150 358.2 329.6 861.6 .2 .3376 2.96 160 363.3 334.9 857.9 1192.8 .3589 2.79 170 368.2 339.9 854.4 1194.3 .3801 2.63 180 372.9 344.7 851.0 1195.7 .4012 2.49 190 377.4 349.3 847.7 1197.0 .4223 2.37 200 381.6 353.7 844.6 1198.3 .4433 2.26

## Table LIII - Continued

 Properties of Saturated Steam of from 32 Degrees to 212Degrees Fahr. at Pressures underOne Atmosphere Temperature Degrees Fahr. Pressure Total Heat ofOne PoundReckoned from Water at32 DegreesFahr.Units Weight of 100 CubicFeet Pounds Volume ofOne Pound ofVapor Cubic Feet Inches of Mercury Pounds per Square Inch 32 .181 .089 1091.2 .031 3226 35 .204 .100 1092.1 .034 2941 40 .248 .122 1093.6 .041 2439 45 .299 .147 1095.1 .049 2041 50 .362 .178 1096.6 .059 1695 55 .426 .214 1098.2 .070 1429 60 .517 .254 1099.7 .082 1220 65 .619 .304 1101.2 .097 1031 70 .733 .360 1102.8 .114 877.2 75 .869 .427 1104.3 .134 746.3 80 1.024 .503 1105.8 .156 641.0 85 1.205 .592 1107.3 .182 549.5 90 1.410 .693 1108.9 .212 471.7 95 1.647 .809 1110.4 .245 408.2 100 1.917 .942 1111.9 .283 353.4 105 2.229 1.095 1113.4 .325 307.7 110 2.579 1.267 1115.0 .373 268.1 115 2.976 1.462 1113.5 .426 234.7 120 3.430 1.685 1118.0 .488 204.9 125 3.933 1.932 1119.5 .554 180.5 130 4.509 2.215 1121.1 .630 158.7 135 5.174 2.542 1122.6 .714 140.1 140 5.860 2.879 1124.1 .806 124.1 145 6.662 3.273 1125.6 .909 110.0 150 7.548 3.708 1127.2 1.022 97.8 155 8.535 4.193 1128.7 1.145 87.3 160 9.630 4.731 1130.2 1.333 75.0 165 10.843 5.327 1131.7 1.432 69.8 170 12.183 5.985 1133.3 1.602 62.4 175 13.654 6.708 1134.8 1.774 56.4 180 15.291 7.511 1136.3 1.970 50.8 185 17.044 8.375 1137.8 2.181 45.9 190 19.001 9.335 1139.4 2.411 41.5 195 21.139 10.385 1140.9 2.662 37.6 200 23.461 11.526 1142.4 2.933 34.1 205 25.994 12.770 1143.9 3.225 31.0 210 28.753 14.126 1145.5 3.543 28.2 212 29.922 14.700 1146.1 3.683 27.2