Document daMk8x61vk0KYb2kq2wmoKeNR

American Society of Heating and Ventilating Engineers Guide, 1931 Table 13. Properties of Dry Air* Barometric Pressure 89.921 In. Temperature, Dso. Fahb. Weight pkb Cubic Foot, Pound Ratio or Volume to Volume at 70 Deo. Fa hr B.t.u. Absorbed bt 1 Cu. Ft. Dbt Am per Deo. Fahr. Cubic Feet Drt Am Warmed 1 Deg. per B.t.u. -50 -45 -40 --55 -30 -25 -20 -15 -10 -5 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 ' 145 150 160 170 180 190 200 220 240 260 280 300 350 400 450 500 550 600 700 800 900 1000 1200 0.09690 0.09573 0.09459 0.09348 0.09239 0.09133 0.09029 0.08927 0.08828 0.08731 0.08636 0.08544 0.08453 0.08363 0.08276 0.08190 0.08107 0.08025 0.07945 0.07866 0.07788 0.07713 0.07640 0.07567 0.07495 0.07424 0.07356 0.07289 0.07222 0.07157 0.07093 0.07030 0.06968 0.06908 0.06848 0.06790 0.06732 0.06675 0.06620 0.06565 0.06510 0.06406 0.06304 0.06205 0.06110 0.06018 0.05840 0.05673 0.05516 0.05367 0.05225 0.04903 0.04618 0.04364 0.04138 0.03932 0.03746 0.03423 0.031S1 0.02920 0.02720 0.02392 0.7735 0.7829 0.7924 0.8018 0.8112 0.8206 0.8301 0.8396 0.8490 0.8585 0.8680 0.8772 0.8867 0.8962 0.9057 0.9152 0.9246 0.9340 0.9434 0.9530 0.9624 0.9718 0.9811 0.9905 1.0000 1.0095 1.0190 1.0283 1.0380 K0472 1.0570 1.0660 1.0756 1.0850 1.0945 1.1040 1.1133 1.1230 1.1320 1.1417 1.1512 1.1700 1.1890 1.2080 1.2270 1.2455 1.2833 1.3212 1.3590 1.3967 1.4345 1.S288 1.6230 1.7)77 1.8113 1.9060 2.0010 2.1900 2.3785 2.5670 2.7560 3.1335 . 0.02335 0.02307 0.02280 ' 0.022S3 0.02226 0.02201 0.02176 0.02151 0.02127 0.02104 0.02080 0.02060 0.02039 0.02018 0.01998 0.01977 0.01957 0.01938 0.01919 0.01900 0.01881 0.01863 0.01846 0.01829 0.01812 0.01795 0.01779 0.01763 0.01747 0.01732 0.01716 0.01702 0.01687 0.01673 0.01659 0.01645 0.01631 0.01618 0.01605 0.01592 0.01578 0.01554 0.01530 0.01506 0.01484 0.01462 0.01419 0.01380 0.01343 0.01308 0.01274 0.01197 0.01130 0.01070 0.01018 0.00967 0.00923 0.00847 0.00782 0.00728 0.00680 0.00603 . Prom Mechanical Equipment of Buildings, VoL 1, by Harding and Willard, second edition, 1929. 42.82 43.34 43.87 44.39 44.91 45.43 45.96 46.48 47.00 47.52 48.08 48.55 49.05 49.56 50.05 50.58 51.10 51.60 52.11 52.64 53.17 ` 53.68 54.18 54.68 55.19 55.72 56.21 56.72 57.25 57.74 58.28 58.76 59.28 59.78 60.28 60.79 61.32 61.81 62.31 62.82 63.37 64.35 65.36 66.40 67.40 68.41 70.48 72.46 74.46 76.46 78.50 83.55 88.50 93.46 98.24 103.42 108.35 118.07 127.88 137.37 147.07 165.83 22 Chapter 3 HEAT LOSSES BY TRANSMISSION Transmission Coefficients by Test; Transmission Coefficients by Computation; Areas Where Transmission Losses Occur; Calcu lations for Transmission Losses; Economic Value.of Insulation. THE heat losses of a building are of two kinds; (1) the transmission losses through the walls, floors, roof, ceiling and windows, and (2) the infiltration losses through the cracks, crevices, etc., around doors and windows and through solid materials. Infiltration losses are treated in Chapter 4. The transmission losses are computed by' taking into account the heat transmission coefficients (See par. 5, p. 81) of the walls, roofs, etc., of the building. These coefficients may be determined experimentally by test, or they may be computed with sufficient accuracy when certain physical constants are known. TRANSMISSION COEFFICIENTS BY TEST Hot-Box Method: The standard method of testing built-up wall sections is by means of the guarded hot-box1, which consists of an insulated outer box about 5 ft. x 5 ft. x 5 ft., and an inner box about 3 ft. x 3 ft. x 3 ft., also insulated. The wall specimen is clamped to the open side of the outer box and in this position must come in firm contact with the edges of the open side of the inner box. The air in the inner box is heated by means of a resistance coil wound on a cubical frame, and the temperatures in the two boxes controlled thermostatically to maintain the same temperature in each. Fans are installed to maintain uniform temperatures in these two spaces with a minimum circulation of air. The heat transferred through the wall specimen is readily estimated from the heat input of the inner box, and the air-to-air coefficient of the specimen for still-air conditions determined by dividing this heat-loss by . the area of the specimen through which the heat passes, the temperature difference of the air on the two sides of the specimen and the number of hours of the test. Nicholls Heat Meter: The Research Laboratory of the American Society of Heating and Ventilating Engineers has. developed an apparatus known as the Nicholls heat meter for the determination of the heat transmission coefficient of any type of construction under natural weather conditions.2 The Nicholls' heat meter consists essentially of a *See Standard Code for Heat Transmission through Walls (A.S.H.V.E. Transactions, Vol. 34, 1938). *See Measuring Heat Transmission in Building Structures and a Heat Transmission Meter, by P. Nicholls (A.S.H.V.E. Transactions, Vol. 30, 1924), 23