Document zQwwqVyJzqYqkJyBvEKGjbNB6

450 CHAPTER 24 .1965 Guide And. Data Book Table 22 .. .. Heat Losses, from Horizontal Bare Steel Pipes and Hat Surfaces. (a stu per (Sq ft of Pip* Surface} (Hood (F Deg Temperature Difference Between Pipe end Mr] India* Umar Pool factor* 50 Temperature Difference F Deg Betaeen Pip* Surface trad Surrounding Mr. Air at BO F. 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 900 950 1000 H 0.220 2.12 2.48 2.80 3.10 3.42 3.74 4.07 4.47 4.86 5.28 5.72 6.19 6.69 7.22 7.79 8.39 9.03 9.70 10.42 11.18 H 1 0.275 2.08 2.43 2.74 3.04 3.35 3 67 4.0U 4.40 4.79 5.21 5.65 6.12 6,61 7 15 7.71 8.31 8.95 9.62 10.34 11.09 0.344 2 04 2.38 2.6S 2 W 3.30 3.61 3.94 4.33 4.72 5.14 5.58 6.05 6.64 7.07 7.64 8.23 8.87 9.66 10.26 11.02- IX 0.435 2.00 2.34 2.64 2.93 3.24 3.55 3.88 4.27 4.66 5.07 5.51 5.97 6.47 7.00 7.66 8.16 8.79 9.47 10.18 10.94 1H 2 0.497 0.622 1.98 2.31 2.61 2.9(1 3 20 3,52 3:84 4.23 4.62 5.03 5.47 5.93 6.43 6.98 7.52 8.12 8.75 9.43 10.14 10.89 1.95 2.27 2.56 2.85 3.15 3 46 3.78 4.17 4.56 4.97 5.41 6.87 6.37 6.89 7.46 8.06 8.68 9.36 10.0/ 10.82 2K 0.753 1.92 2.23 2.52 2.81 3 11 3.42 3.74 4.12 4.51 4.92 5.36 6.82 6.31 6.84 7.4U 7.99 8.63 9.30 10.01 10.77 3 0.916 1.89 2.20 2.49 2.77 3.07 3.37 3.69 4.08 4.46 4.87 5.31 5.77 6.26 6.79 7.36 7.94 8.67 9.26 9.96 10.71 3H 1.047 1 87 2.18 2.46 2.74 '3,04 3.34 3.66 4.05 4.43 '4.84 5.27 5.73 6.23 6.75 7.31 7.91 8.54 9.21 9.92 10.67 4 1.178 1 85 2.16 a 44 2 7S 3 m 3 32 3.64 4.02 4.4(1 4.81 5.25 5.71 6.20 6.72 7.28 7.87 8.61 9.18 9.89 10.64 4K 1.309 1.84 2.14 2.42 2.70 2.99 3 3(1 3.61 4.00 4,38 4,79 5.22 5.68 6.17 6.69 7.26 7.85 8.48 9.16 9.86 10.61 6 1.456 1.83 2.13 2.40 2.68 2.97 3.28 3.59 3.97 4.35 4.76 5.20 5.65 6.15 6.68 7.23 7.82 8.46 9.12 9.83 10.58 6 1.734 1.80 2.10 2.37 2.65 2.94 3 24 3.55 3.94 4.32 4.721 5.16 5.61 6.10 6.63 7.19 7.78 8.41 9.08 0.79 10.54 7 1.996 1.79 2 08 2,35 2 63 2.91 3.21 1M 3.91 4 29 4.69 5.13 5.58 6.07 6.6(1 7.16 7.76 8.33 9.06 9.76 10.51 8 2.258 1.77 2.06 2.33 2.6(1 2 fill 3.19 3.5(1 3.88 4.26 4.67 5.10 5.56 6.05 6.67 7.12 7.72 8.36 9.02 9.73 10.48 9 2.520 1.76 2.05 2.31 2.59 2.87 3.17 3.48 3.86 4.24 4.65 5.08 5.53 6.02 6.64 7.10 7.69 8.32 8.99 9.70 10.45 10 2.814 1.75 2.03 2.30 2.57 2.85 3 15 3 46 3,84 4.22 4.62 5.05 5.51 ft 00 6.62 7.08 7.67 8.30 8.97 9.68 10.43 12 3.2OS 1.72 2.01 2.25 2 M 2.83 3.12 3.42 3.81 4.19 4.5f 5.02 5.43 5.96 6.43 7.04 7.63 8.2d 8.93 9.64 10.39 14 3.665 1.75 2.(K 2.2f a 5? 2.81 3 11 3.41 3.79 4.15 4.51 6.UC 6.46 5.94 6.47 7.02 7.61 8.24 8.91 9.62 10.37 16 4.189 1.70 1.98 2.24 2.51 2.79 3.08 s.sy 3.77 4.14 4.55 4.98 5.43 5.92 6.44 6.99 7.69 8.21 8.88 9.to 10.34 18 4.717 20 6.236 24 6.283 Vertical 8cITface Horizontal Facing Upward Horixontal Surface Facing Downward 1.69 1.96 2 27 2 49 2.77 3.07 3.37 3.75 4.12 4.53 4.96 5.41 5.90 6.42 6.97 7.56 8.19 8.86 9.67 10.32 1.68 1.95 2.21 2.41 2.75 3.05 3.3f 8.VS 4.11 4.51 4,94 6.39 6.83 6.4C 6.95 7.64 8.17 8.84 9.5^ 10.29 1.66 1 K 2.15 2.45 9 7? 3.05 3.3? 3.71 4.01 4.41 4.91 5.:i 5.84 6.36 6.92 7.6J ,8.14 8.8C 9.6J 10.26 1.84 2.14 2.42 2.70 3.00 3.30 3.62 4.00 4.38 4.79 5.22 6.68 6.17 6.70 7.2b 7.86 8.48 9.15 9.86 10.62 2.03 2.37 2.67 2.97 3.28 3.59 3.92 4.31 .4.70 5.12 5.56 6.02 6.52 7.05 7.61 8.21 8.85 .9.52 10.24 10.99 1.61 1.86 2.11 2.36 2.64 2.93 3.23 3.60 3.97 4.37 4.80 5.25 5.73 6.25 6.80 7.39 8.02 8.69 9.39 10.14 Value* an for Rat Bmftees (oar eqwe (set or mere in ana. * To neun Iona per linear foot, moltip(7 eq ft fonaa in table by this foctor. The k * per aq ft of pipe torfoee for pipes larger than 14 in. can be onaairicred the emeu the loon for the 14-in- pip*. Solution; fi, 1 uRe 0.14 Then, by Equation 9: 7.14. 1Q 1.80 70 -fc. 7.14 " 70 - ( - 20) t, - 47.3 P. The concrete surface temperature is of interest since'refer* ence to a psychrometric chart or table will show that moisture condensation could occur on this surface under the above conditions (47.3 F) if the relative' humidity in the room ex ceeds 44 percent Additional roof insulation should be con sidered above the slab to avoid condensation at this point if higher relative humidities in the room are anticipated. The same procedure can be used for determining the tem perature at any point within the structure. A chart for determining inside wall surface temperature is given in Fig. 13 of Chapter 14 of the 1964 Guide And Data Book. CONDUCTIVITY OF INDUSTRIAL INSULATIONS The conductivities of various materials used for insulating .steam and hot water'systems are given in'Table 21. They are given as functions of the mean temperatures or the arithmetic mean of the inner and outer surface, temperatures of the in sulations. BARE SURFACE HEAT LOSSES--FLAT . SURFACES AND PIPE . Heat losses from horizontal bare steel pipes, based on tests at Mellon Institute and ca1r.nlAt*rf from the fundamental radiation and convection equations (Chapter 4), are given in Table 22. This table also gives the heat losses or surface con ductances for flat, vertical, and horizontal surfaces forsurface temperatures up to 1080 F with the surrounding air"at 80 F. The surface per linear foot of pipe is given in the second column of Table 22. Design Heat Transmission Coefficients 451 Table 23 .. Heat Losses from Bare Tarnished Capper Tube* Temperature of Tube, f 120 150 180 *10 240 270 300 330 - Moadnel Diameter of Temperature Difference, Tube to Mr, F Deg 80 110 uo 170 200 230 260 . , .' X ft ft i X IK ' 1H 2H Heat lots per faaor Foot of Tube, Btu per Hr. 8 14 21 29 37 46 56 66 10 18 28 37 48 60 72 85 13 22 33 45 59 72 88 104 15 26 39 53 08 85 102 121 17 30 46 61 ; 79 97 117 139 21 37 55 75 97 120 146 173 75 45 66 90 117 145 ` 175 207 29 52 77 1115 135 16"/ 203 241 37 66 97 132 171 212 257 305 44 78, 117 160. 206- 255 310 367 51 92 136 186 240 297 360 428 3X 4 59 104 156 212 274 340 ' 66 118 174 238 307 381 412 462 490 550 5 80 142 212 288 373 464 561 -669 6 93 166 246 336 432 541 -656 776 8 120 215 317 435 562 699 848 1010 10 146 260 387 SHI 681 848 1031 1227 12 172 304 447 621 802. 999 1214 1446 * Extracted trdm Beferenoe 9, Oaed by petmueioa. Heat losses from tarnished copper pipe and tube' are given in .Table 23.'The surface per linear foot of tube is given in Table 24. Table. 2, Section A, also gives the surface con ductances for flat surfaces of different emissivities antLorientations in contact with still air. Table25 gives the area,- in square feet, of flanges and fittings for various standard pipe sizes. These tables can be used to advantage in estimating the amount of insulation required. Example IS shows how the *nnmj heat loss from uncovered pipe may be computed from the data in Table 22. Example IS: Compute the total annual heat loss from 165 ft of 2 in. bare pipe in service 4000 hr-per'year. The pipe is carry- Table 24 .... External Surface per Linear Foot of Copper Tubing Outride diameter ^ fa. giNhr (baa nominal *** (fneftei) Surface Area Tube Size Surface Area Tab* Site Surface Area (Sq Ft) (Jndns) (Sq Ft) (Inched (Sqft) X ' 0.164 2 0.556 s 1.342 H 0.229 2X 0.687 6 1.604 1 0.295 3 0.818 8 2.123 IX 0.380 3X 0.949 IX . 0.426 4 1.080 mg steam at 10 pei pressure temperature of 80 F. is* exposed to an average air Solution: The pipe temperature is taken as the steam tem- perature,which is 239.4 F, obtained tor interpolation from Steam Tables. The temperature difference between the pipe and air = 239.4 -- 80 -- 159.4 F. By interpolation in Table 22 between temperature differences of 150and 200 F, the heat loss from a 2-in. pipe at a temperature difference of 159.4 F is found to be 2.615 Btu per (hr) (aq ft) .(F deg). The total annual heat loss from the entire line - 2.615 X 159.4 X 0.622 (linear ft factor) X 165 (linear ft) X 4000 (hr) - 171,100 (MB - 1000 Btu). HEAT ROW CALCULATIONS In calculating heat flow, Equations 10 and 11 are generally used. Equation 10 is used for flat surfaces (Fig. 5)) and Equa tion 11 is used for cylindrical surfaces (Fig. 6).. GO) (ID xohere q, -- rate of heat transfer per square foot of outer surface of insulation, Btu per (hour) (square foot). Nominal ftp* Sir* (Indtei) 1 IK 2K 3 3K <x 5 6 8 Table -25 ..Area of Hanged Fittings, Square Feet* flanged Coupling 90 Deg 0 long Radon St TM Cron Standard Extra Heavy 0.320 0.383 0.477 0.672 0.841 0.438 0.510 0.727 0.848 1.107 0.945 1.122 L344 1.474 1.622 1.484 1.644 1.914 2.04 2.18 1.82 2.78 2.41 3.77 3.43 5.20 4.41 - . 6.71 Standard Extra Heavy Standard Extra Heavy Standard Extra Heavy .Standard Extra - Heavy 0.795 0.957 ' 1.174 ' 1.65 2.09 2.33 2.98 3.53 3.95 4.44 5.13 6.98 10.18 13.08 1.015 1.098 1.332 2.01 2.57 3.49 3.96 4.64 5.02 5.47 6.99 9.76 13.58 17.73 0.892 1.084 1.337 1.84 2.32 2.68 3.28 3.96 4.43 5.00 5.99 8.56 12.35 16.35 1.083 1.340 1.874 2.16 2.76 3.74 4.28 4.99 5.46 6.02. 7.76 11.09 15.60 18.76 1.235 1.481 1.815 2.54 3.21 1.575 1.925 2.68 . 3.09 4.05 3.66 - 4.48 5.41 6.07 6.81 5.33 - 6.04 7.07 7.72 8.52 7.84 . 10.55 15.41 19.67 . 10.64 14.74 20.41 26.65; 1.622 1.943 2.38 3.32 4.19 4.77 5.83 7.03 7.87 8.82 10.0S 13.44 19.68 24.87 2.07 2.53 3.54 4.06 5.17 6.95 7.89 9.24 10.07 10.97 13.75 18.97 26.28 34.11