Document zGxwBEmO5GoGeNKLGMGO7qGn

American Society of Heating and Ventilating Engineers Guide, 1932 tures, an electromotive force will be set up between these junctions. Its amount will depend on the composition of the wires and the difference in temperature. When one junction is held at a constant temperature, the electromotive force will be dependent on the temperature of the other junction, and if a delicate galvanometer of high resistance be connected to the thermocouple, as it is called, the deflection of the needle will indicate the temperature of this other junction. Instruments for the measurement of high temperatures are calibrated with the aid of the known melting points of pure metals. Table. 4 Properties of Saturated Steam3 (Continued) Absolute Pbessube, S<L In Tem- PERATUBE. Deg.Fahb. Volume, Cu. Ft. peb Lb. Weight, Lb. peb Cu. Ft. Heat Content in B.t.u. Latent Heat in B.t.u. Entbopt of of of Vapor- In- of of Vapor Liquid Vapor ization ternal 1 Liquid ization Vapor P 120 122 124 126 128 130 132 134 136 138 140 142 144 146 148 150 152 154 156 158 160 162 164 166 168 170 172 174 176 178 180 182 184 186 188 100 192 194 196 198 200 202 204. 206 208 210 212 214 216 218 220 t 341.3 342.5 343.7 345.0 346.2 347.4 348.5 349.7 350.8 352.0 353.1 354.2 355.3 356.3 357.4 358.5 359.5 360.5 361.6 362.6 363.6 364.6 365.6 366.5 367.5 368.5 369.4 370.4 371.3 372.2 373.1 374.0 374.9 375.8 376.7 377.6 378. S 379.3 380.2 3S1.0 381.9 382.7 383.5 384.4 385.2 386.0 386.8 387.6 388.4 389.2 390.0 **fg 3.735 3.676 3.626 3.566 3.513 3.461 3.412 3.363 3/316 3.270 3-226 3.182 3.140 3.099 3:059 3.020 2.982 2.945 2.909 2.874 2.839 2.806 2.773 2.741 2.710 2.679 2.649 2.620 2.591 2.563 2.536 2.509 2.483 2.457 2.432 2.408 2.383 2.360 2.337 2.314 2.292 2.270 2.248 2.227 2.206 2.186 2.166 2.147 2.128 2.109 2.090 1 ^fg 0.2678 0.2720 0.2762 0.2805 0.2847 0.2889 0.2931 0.2973 0.3016 0.3058 0.3100 0.3142 0.3184 0.3227 0.3269 0.3311 0.3353 0.3396 0.3438 0.3480 0.3522 0.3564 0.3606 0.3648 0.3691 0.3733 0.3775 0.3817 0.3859 0.3901 0.3943 013985 0.4027 0.4069 0.4111 0.4154 0.4196 0.4238 0.4280 0.4322 0.4364 0.4406 0.44480.4490 0.4532 0.457 0.462 0.466 0.470 0.474 0.478 h 311.9 313.2 314.4 315.7 316.9 318.2 319.4 320.6 321.8 323.0 324.2 325.3 326.5 327.6 328.7 329.8 330.9 332.0 333.1 334.1 335.2 336.2 337.3 338.3 339.3 340.3 341.3 342.3 343.3 344.3 345.2 346.2 347.1 348.1 349.0 350.0 350.9 351.8 352.7 353.6 354.5 355.4 356.2 357.1 358.0 358.8 359.7 360.5 361.4 362.2 363.0 h% 1191.4 1191.6 1191.9 1192.1 1192.4 1192.6 1192.9 1193.1 1193.3 1193.5 1193.7 1193.9 1194.1 1194.3 1194.5 1194.7 1194.9 1195.1 1195.3 1195.5 1195.7 1195.8 1196.0 1196.2 1196.3 1196.5 1196.6 1196.8 1196.9 1197.1 1197.2 1197.4 1197.5 1197.6 1197.8 1197.9 1198.0 1198.1 1198.2 1198.4 1198.5 1198.6 1198.7 1198.8 1198.9 1199.0 1199.1 1199.2 1199.3 1199.4 1199.5 ^fg 879.5 878.5 877.5 876.4 875.4 874.4 873.5 872.5 871.5 870.5 869.6 868.6 867.7 866.8 865.8 864.9 864.0 863.1 862.3 861.4 860.5 859.6 858.7 857.9 857.0 856.2 855.3 854.5 853.6 852.8 852.0 851.2 850.4 849.5 848.7 847.9 847.1 846.3 845.6 844.8 844.0 843.2 842.5 841.7 840.9 840.2 839.4 838.7 837.9 837.2 836.5 U St Sfg SZ 796.9 795.8 794.8 793.7 792.6 791.6 790 5 789.S 788.5 787.4 786.4 785.4 784.5 783.5 782.5 781.6 780.6 779.7 778.7 777.8 776.9 776.0 775.1 774.2 773.3 772.4 771.5 770.6 769.8 768.9 768.0 767.2 766.4 765.5 764.7 763.9 763.0 762.2 761.4 760.6 759.8 759.0 758.2 757.4 756.7 755.9 755.1 754.3 753.6 752.8 752.1 0.4911 0.4927 0.4943 0.4958 0.4974 0.4989 0.5004 0.5019 0.5033 0.5048 0.5062 0.5076 0.5090 0.5104 0.5117 0.5131 0.5144 0.5157 0.S170 0.5183 0.5196 0.5209 0.5221 0.5233 0.5245 0.5258 0.5270 0.5281 0.5293 0.5305 0.5316 0.5328 0.5339 0.5350 0.5361 0.5372 0.5383 0.5394 0.5404 0.5415 0.5426 0.5436 0.5446 0.5457 0.5467 0.5477 0.5487 0.5497 0.5507 0.5516 0.5526 1.0982 1.0952 1.0922 1.0894 1.0865 1.0836 1.0808 1.0781 1.0754 1.0727 1.0700 1.0674 1.0648 1.0623 1.0598 1.0573 1.0548 1.0524 1.0500 1.0476 1.0453 1.0429 1.0406 1.0384 1.0361 1.0339 1.0317 1.0295 1.0274 1.0252 1.0231 1.0210 1.0189 1.0169 1.0148 1.0128 1.0108 1.0089 1.0069 1.0049 1.0030 1.0011 0.9992 0.9973 0.9954 0.9936 0.9918 0.9900 0.9881 0.9864 0.9846 1.5893 1.5879 1.5865 1.5852 1.5838 1.5825 1.5812 1.5800 1.5787 1.5775 1,5762 1.5750 1.5738 1,5727 .1,5715 1.5704 1.5692 1.5681 1.5670 1.56S9 1.5649 1.5638 1.5627 1,5617 1.5607 1.5597 1.5587 1.5577 1.5567 1.5557 1,5547 1.5538 1.5528 1.5519 1.5509 1.5500 1.5491 1.5482 1.5473 1.5464 1.5456 1.5447 1.5438 1.5430 1.5421 1.5413 1.5405 1.5396 1.5388 1.5380 1.5372 This table U abstracted by permission from Properties of Steam and Ammonia, by the late Prof. G. A. Goodenough. 536 Chapter 39--Physical Data In the measuring of room temperatures care must be exercised to pre vent the results from being affected by the body heat of the observer, by drafts from doors, windows and other openings or by radiant heat from some local source such as a radiator, wall, etc. All thermometers should be mercury thermometers with engraved stems. The total gradua tions of the thermometers should be from 20 to 120 F, in one degree graduations. No ten degrees should occupy a space of less than one-half inch. The accuracy throughout the whole scale must be within one-half degree. The operator should take,hold of the top and no part of the body, including the hand, should be nearer than 10 in. to the bulb. The thermometer should not be closer than 5 ft to any door, window, or other opening; should not be closer than 12 in. to any wall; and should be between 3 and 5 ft from the floor. A sling instrument should be used for extreme accuracy. For measuring duct temperatures an angle-duct thermometer should be used, having a flange to bolt on the side of the duct, with the bulb extending into the duct at least 6 in. Recording thermometers generally have considerable lag and should not be used for the taking of temperatures for testing, but rather for giving continuous records of the operation of the plant, as the charts will indicate any lack of attention on the part of those responsible for the operation of the plant. Humidity The sling psychrometer is the recognized standard instrument for determining humidities. In order to obtain accurate readings consider able skill is required on the part of the operator. The wicking must be clean, distilled water should be used, and the temperature of the water should be slightly above the wet-bulb temperature of the surrounding air. The psychrometer should be swung rapidly and two or three obser vations should be made to see that the wet-bulb temperature has become stationary before the final reading is noted. Standard psychrometric tables should be used. In taking humidity readings in ducts it is usually impracticable to use a sling psychrometer. For this work the stationary hygrodeik arranged for bolting on to the side of the duct, with two bulbs extending into the duct, will be found very convenient. Due to the velocity of the air passing over the bulbs within the duct an accurate reading will be secured, corresponding to that given by the sling psychrometer. CO* Determinations At ordinary concentrations carbon dioxide is not harmful. The amount of carbon dioxide in the air is a convenient index of the rate of air supply, and of the distribution of the air within large rooms. A high carbon dioxide concentration in parts of an occupied room may indicate air stag nation which can result in objectionable odors or in failure to remove local surplus heat. The Petterson-Palmquist apparatus has been generally accepted as the standard device for the determination of carbon dioxide in air investiga tions. The principle involved is the measurement of a given volume of 537