Document bBz5ME5GzGonzJL3QO7EnQYmD

504 CHAPTER 21 1951 Guide Table 2. Heat-carrying Capacity of Standard Black Pipes with Temperature Drop of 20 Deg Nominal Pipe Sizes % in. to IS in., and Friction 4 to 800 miHnehes perfool (A = Capacity, Moh. B = Velocity, inches per second) (One milinch equals 0.001 in.) Mclutch Frio* Foot or Pipb 4A B 6A B 8A B WA B 13 A B 14 ' A B to A B SO A B 39 A B 30 A B 85 A B. 40 A B 50 A B 00 A B 70 A B 80 A B 100 A B 160 . A B 300 A B 800 A B 400 A B 800 A B 000 A B 800 A B Nominal Pips Sees. Itches H X H 1 IK IX 2 m 8 ax 4 5 6 8 10 12 0.75 165 2.85 5.4 114 174 334 53.1 95 141 197 363 596 1250 2320 3730 16 1.7 2.1 2.4 2.9 83 86 46 54 66 64 74 7.9 9.6 11 12 06 1,7 8.6 '6,75 144 213 413 664 119 176 248 456 748 1570 2920 4690 U 2.1 2.6 34 34 44 4.7 53 63 64 73 83 10 12 14 16 1.05 20 42 79 16.4 248 484 779 140 207 291 635 879 1850 3440 5520 2.1 26 3.0 36 43 4.7 5.6. 66 73 8.0 83 10 12 14 17 19 1.2 2.2 47 89 184 28.0 54.7 881 158 234 329 605 997 2100 3910 6270 2.4 26 3.4 44 46 53 66 7.1 83 9.1 9.9 12 13 16 19 27 185 2.45 5.2 96 206 814 60,4 97.4 175 259 364 671 1100 2320 4330 6950 2.7 8.1 8.7 4.4 56 54 64 76 9.1 10 11 13 15 18 21 24 1.45 2.65 5.65 10,7 223 83.7 656 106 190 282 897 731 1200 2530 4730 7590 2.9 3.4 4.1 46 6.7 6.4 74 84 94 11 12 14 16 20 23 26 1.55 8.85 6.05 116 24.0 863 706 114 205 803 428 787 1300 2730 5100 8190 8.1 8.6 4.4 5.1 63 : m 84 9.7 11 12 13 15 17 21 25 28 1.75 8.25 665 134 27.1 414 80.0 129 232 844 484 892 1470 3100 6790 9300 86 44 4.9 56 74 7.7 93 10 12 18 16 17 20 24 . 28 32 2.0 8.65 7,75 14.7 304 466 906 146 .263 889 548 1010 1670 8510 6570 10560 .44 4.6 5.6 66 74 86 10 12 14 15 17 19 22 27 82 86 22 44 855 163 336 51.2 100 162 290 430 607 1120 1850 8900 7280 11710 4.4 54 6J 73 8.7 9.7 11 18 15 17 18 22 25 30 85 40 265 4.4 96 17.6 366 55.7 109 176 816 469 661 1220 2010 4250 7940 12780 4.7 66 6.7 74 94 11 18 14 16 18 20 23 27 33 89 44 265 6.1 4,7 100 189 896 594 6.9 73 &4 10 11 117 S3 186 841 15 18 505 20 712 1820 2170 4580 8570 13780 22 25 29 35 42 47 265 56 116 21.4 44.7 67.7 183 214 886 572 807 1490 2460 5190 9720 15650 6.7 6.7 8.1 96 12 13 15 17 20 22 24 29 83 40 47 54 815 585 12,4 23.6 49.4 744 147 238 427 633 893 1650 2730 5760 10780 17300 06 7A 8.9 , 11 13 14 17 19 22 25 27 82 36 44 62 60 8.45 665 136 25.7 636 81.4 6.9 84 9.7 11 14 15 160 18 258 21 465 24 690 27 973 1800 2970 6280 11760 18950 29 85 40 48 57 65 8.7 7.4 6,8 146 274 57.9 874 8.6 10 12 15 17 172 278 20 22 500 26 743 1050 1940 3200 6770 12690 20440 29 32 37 43 62 62 70 415 86 7.7 16.4 31.1 65.4 990 9.7 12 14 . 17 19 194 22 314 666 25 30 840 1190 2200 8630 7680 14400 23200 83 86 42 48 69 70 80 52 10 96 20.4 38.8 814 12 15 17 21 124 23 243 393 709 1050 1490 2760 4560 9650 18120 29220 28 32 37 41 45 68 61 74 88 10S 605 11.2 23.9 45.4 956 12 14 17 20 25 145 27 285 33 461 37 832 1240 1750 3240 5360 11350 21320 34400 43 , 48 53 62 71 87 104 118 76 13.9 29^ 564 .119 15 18 31 25 31 181 84 856 41 577 1040 1550 2190 4060 6730 14270 26830 43300 46 54 60 66 78 90 110 131 149 8.75 163 34.7 66.2 18 21 26 80 HO 36 212 40 417 48 676 1220 1820 2570 4780 7910 16790 31S80 51000 64 64 71 . 78 92 105 129 154 175 965 186 893 746 20 23 29 . >8 158 41 239 45 471 64 765 1380 2060 2910 5410 8970 19040 35840 67880 62 72 80 88 104 119 147 174 199 10.9 20.2 433 825 22 26 32 37 174 45 264 50 521 60 846 1530 2280 8220 5990 9930 21100 39740 64S10 68 80 89 97 115 132 162 193 221 12.7 23.6 506 966 25 80 37 43 204 52 810 59 610 70 992 1760 2670 3780 7030 11670 24820 46780 75620 80 94 104 114 135 155 191 228 260 For other temperature drops the pipe capacities may be changed correspondingly. For example, with I temperature drop of 30 deg toe capacities shown in this table are to be maJtipiieo by 1.5. \ Hot Water Heating Systems 505 alent number of elbows of the same pipe size which would have the same friction loss. An elbow is assumed to have the same friction' loss as a straight pipe having a length equal to 25 diameters (nominal) of the elbow. The resistance of various types of fittings expressed in equivalent elbow resistance is shown in Table 1. The friction loss in pipes and tubing may be determined from Fig. 2 and Table 2 for black iron pipes, and from Fig. 3 and Table 3 for type L copper tubing. The scale at bottom of Figs. 2 and 3 is the heat carrying capacity in thousands of Btu per hour based on a 20 deg temperature difference between flow and return risers. In order to use the scale for other than 20 deg difference, refer to footnote under Figs. 2 and 3. If the flow in a given pipe is calculated in pounds per how, it may be FLOW OF WATER IN GALLONS PER MINUTE Lower acute of char, is based on 20 deg temperature difference between flow and return risen. To find Irirtion when temperature drop ts other than 20 deg. multiply tbs actual heat conveyed by ( actual temp, drop ) "d ra*d the corre,poIld" friotton- converted to corresponding gallons per minute by dividing the flow in pounds by 500, after which the friction may be found by entering Figs. 2 and 3 at the top scale reading which corresponds to the flow in gallons per minute as determined. Orifices drilled in plates inserted in pipe unions are convenient means for introducing friction, where required to balance various circuits. The friction losses caused by various sizes of orifices are given in Table 4. CLASSIFICATION OF SYSTEMS ' Gravity or forced systems of piping may be classified, according to piping arrangement and type of circulation as shown in Table 5. Flow and return main piping (gravity systems) for one-pipe, two-pipe direct return, and two-pipe reversed return systems are shown in Figs. 4, 5, and 6, re-1