Document YGdDKb8wZa2a0d155L6LXJYXk

468 CHAPTER 32 Table 2------Heot Losses from Horizontal Bare Steel Pipes and Flat Surfaces h tfo per [Sq Ft of Pipe Woce) {Hour) (f Deg Temperator* Difference Between Pip* and Air) 1960 Guide P* Str# tadw* I linear fwrf Focter* SO TeAverofvre Difference F Deg Between Ftp* Surface and Surrounding Air. Air at 80 F. TOO 150 200 250 300 350 400 450 500 550 600 700 750 600 850 900 950 1000 x 0.220 X 0.275 0.344 IX 0.435 IX 0.497 0.622 2X 0.753 3 0.916 3H 1.047 4 1.178 *X 1.309 5 1.456 6 1.734 N6 8 2.258 2.520 10 2.814 12 3.338 14 3.665 16 4.189 18 4.717 20 5.236 6.283 Vertical Sur- face 2.12 2.W 2.0 2.00 2.48 2.42 2.31 2.34 2.80 2.7i . 2.64 3.10 S.fc 2.9S 2.93 3.42 3 35 3.3C 3.24 3 74 3.67 3.6i 3.55 4.07 4.00 3.94 3.88 4.47 4.40 4.33 4.27 4.86 4.79 4.66 5.28 5.21 6.14 5.07 5.72 5.65 5.51 6.51 6.19 6.12 6.05 5.97 1.98 1.95 1.92 1.89 2.31 2.2i 2.2< 2.20 2.61 2.66 2.62 2.49 2.90 2.85 2.81 2.77 3.20 3.15 3 11 3.07 3.52 3.46 3 4? 3.37 3.84 3.76 3.74 3.69 4.23 4.17 4.12 4.08 4.56 4.46 5.03 4.9'/ 4.92 4.8/ 5.47 5.41 5.31 5.31 5.93 5.87 5.82 5.77 1.87 1.86 l.M 1.83 2.18 2.16 2.H 2.13 2.46 2.44 2.42 2.40 2.74 2.72 2.7( 2.68 3,fH 3.01 2W 2.97 3 34 3.32 3 3ft 3.28 3 66 3.64 3 61 3.59 4.05 4.02 4.00 3.97 4.43 4.35 4.84 4.81 4.7i 4.76 5.27 5,25 5.22 5.20 5 73 5 71 6 <W 5.65 1.80 l./S 1.77 1.76 2.10 2.06 2.06 2.05 2.37 2.36 2.5E! 2.31 2.65 2.6c 2.6C 2.59 2.94 2.91 2.B9 2.87 3 24 3 21 3.19 3.17 3 55 3 53 3 80 3.48 3.94 3.91 3.88 3.86 4.28 4.24 4.72 4.6H 4.67 4.65 5.16 6.ia 5.It 6.08 5.61 6 68 5.56 5.53 1.75 1.73 1.72 1.70 2.03 2.01 2.00 1.98 2.30 2.27 2.2tj 2.24 2.57 2.54 2.M 2.51 2.85 2.83 2.81 2.79 3 15 3.46 3.121 3.43 3 11 3.41 3.08 3.39 3.84 3.81 3.79 3.77 4.22 4.19 4.14 4.62 4.59 4.57 4.55 5.05 5.02 5.0U 4.98 5.51 6 48 5.46 5.43 1.69 1.66 1.66 1.84 1.96 1.95 1.93 2.14 2.22 2.21 2.19 2.42 2.49 2.47 2.45 2.70 2.77 2.75 2.73 3.00 3.07 3.05 3.02 3.30 3 37 3.36 3.33 3.62 3.75 3.73 4.00 4.12 4.11 4.38 4.53 4.51 4.48 4.79 4.96 4.94 4.90 6.22 5.41 5.39 5.36 5.68 7.22 7.79 8.39 9.03 9 70 10.42 11.18 7.15 7.71 8.31 8.95 9.62 10.34 11.09 7.01 7-tM 8.2i 8.81 9.55 10.26 11.02 7.00 7.56 8.16 8.79 9.47 10.18 10.94 6.96 7.52 8.12 8.75 9.43 10.14 10.89 6.1Si 7.45 8.05 8.6a 9.36 10.01 10.82 6.84 7.4C 7.911 8.6a 9.3C 10.01 10.77 6.79 7.35 7.94 8.57 9.25 9.96 10.71 6.75 7.31 7.91 8.54 9.21 9 9? 10.67 6.72 7.28 7.87 8.61 9.18 9 R? 10.64 6.61 7.25 7.85 8.4& 9 15 9 86 10.61 6.68 7.23 7.82 8.45 9.12 9.83 10.58 6.63 7.19 7.78 8.41 9.08 9.79 10.54 6.60 7.15 7.75 8.38 9.05 9.76 10.51 6.57 7.12 7.72 8.35 9 02 9.73 10.48 6.54 7.10 7.69 8.32 8.99 9.70 10.45 6.52 7.08 7.67 8.30 8.97 9.68 10.43 6.48 7.04 7.63 8.26 8.93 9.64 10.39 6.4V 7.02 7.61 8.24 8.91 9.62 10.37 6.44 6.99 7.59 8.21 8.88 9.59 10.34 6.42 6.97 7.56 8.19 8.86 9.57 10.32 6.40 6.95 7.64 8.17 8.84 9.55 10.29 6.36 6.92 7.51 8.14 8.80 9,51 10.26 6.70 7.26 7.85 8.48 9.15 9.86 10.62 Horizontal Burtace Facing Upward 2.03 2.37 2.67 2.97 3.28 3.59 3.92 4.31 4.70 5.12 5.56 6.02 7.05 7.61 8.21 8.85 9.52 10.24 10.99 Horizontal] Surface Facing Downward 1.61 1.86 2.11 2.36 2.64 2.93 3.23 3.60 3.97 4.37 4.80 6.25 6.25 6.80 7.39 8.02 8.69 9.39 10.14 Values ere for Flat Surfaces four eqoam bet ar aor* ia ere*. ` To eecor* loanee per linear toot, multiply eq ft lceea in table by this factor. The k * *# the faeces tor the ll-ia. pipe. * Pr *q ft of pipe eurtoce for pipe* Urge? then ?4 m. mb be considered the layer must be determined along with the thickness of each. This is readily done in two or three calculations performed as a series of approximations, in which assumptions of thick ness and mean temperature are adjusted as indicated in the discussion which follows. . I& the case of a single thickness of pipe covering, the quan tity of heat transferred per square foot of outer surface of the insulation is given by the equation: where - Tt log, -- Tt q. " Btu per (hour) (square foot of outer surface of insula tion). ri *= outer radius of pipe or inner radius of insulation, inches. ri " outer radius of insulation, inches. k thermal conductivity of insulation, Btu per (hour) (square foot) (Fahrenheit degree per inch). ti ** temperature of inner surfaoe of insulation, Fahrenheit. tt ** temperature of outer surface of insulation, Fahrenheit. It is convenient to work from the outer surface of the in sulation, since the los3 through the covering must be deter mined from the outer surface loss by means of surface loss curves such as given in Fig. 5. The curves were plotted from tests conducted at the Mellon Institute. After the true heat loss is obtained, the loss per square foot of pipe surface can be calculated from the relationship: where ffi = J.(r*/r,) ffi -- Btu per (hour) (square foot outer surface of pipe). The heat loss through two or more thicknesses of insulation applied to a pipe can be calculated by means of the equation: Industrial Insulation Table 3.... Heat lenses from Bare Tarnished Copper Tube1 Horizontal Tubes Temperature of Tube, F 100 ,30 150 180 210 240 270 300 Nominal Diameter of Tube (Indies) Temperafere Difference, Tub* to Air, F Des 30 50 eo no uo ,30 200 230 XXXXX 1IiXx 2 2* 3ZX 4 6 6 8 10 12 Hoot loss per Umar Foot of Tube, Bto per Hr. 4 . 8 14 21 6 - 10 18 28 7 13 22 33 8 15 26 39 9 17 30 45 11 21 37 55 14 25 45 66 16 29 52 77 20 37 66 97 24 44 78 117 28 51 92 136 32 59 104 156 36 66 118 174 43 80 142 212 51 93 166 246 66 120 215 317 80 146 260 387 94 172 304 447 29 37 37 48 45 59 53 68 61 79 75 97 90 117 105 135 132 171 160 206 186 240 212 274 238 307 288 373 336 432 435 562 527 681 621 802 46 56 60 72 72 88 85 102 97 117 120 146 145 175 167 203 212 257 255 310 297 360 340 412 381 462 464 561 541 656 699 848 848 1031 999 1214 330 260 66 85 104 121 139 173 207 241 305 367 428 490 550 669 776 1010 1227 1446 469 300 390 290 320 77 99 121 141 162 201 242 28! 356 429 501 573 644 783 915 1184 1442 1699 88 114 139 L63 187 . 232 279 324 411 496 578 662 744 905 1059 1372 1670 1969 Vertical Tubes Temperature of Tube, F 340100 ,20 ,30 ,80 2,0 240 270 300 330 390 Nomina/ Dioeaeter of Feb* (fndt) Temperature Difference, Tub* to Air, F Deg 30 30 eo no UO ,20 200 230 260 290 320 XXXXH 122ImXX Hoof loss per Linear Foot of Tube, fitv per Hr. 3 6 10 15 21 27 34 41 49 57 66 4 8 14 21 28 38 45 55 65 77 88 5 10 17 26 35 46 57 69 82 96 111 6 12 21 31 42 54 68 82 98 114 132 7 14 24 36 49 64 79 96 114 134 155 10 18 31 46 63 82 102 123 147 172 198 12 21 38 57 77 100 125 151 180 210 243 14 25 45 67 91 118 147 178 212 248 287 18 33 59 88 120 155 192 233 277 325 375 22 41 73 109 148 191 238 288 343 402 464 ZX3 27 49 87 129 176 227 283 343 408 478 552 31 57 101 150 204 264 328 398 474 554 641 4 35 64 114 171 232 300 374 453 539 631 729 5 43 80 142 212 288 373 464 . 661 669 783 905 6 52 96 170 253 344 445 554 670 798 934 1080 8 69 127 228 337 458 592 737 892 1063 1244 1438 10 86 158 281 419 570 737 917 1110 1322 1548 1789 12 103 189 336 501 682 881 1097 1328 1582 1851 2140 1 Fran JUteiuxe 1. 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