Document EbO473145M0VgjGM631KMDZL

708 CHAPTER 27 1958 Guide Table 3. Heat Loss from Horizontal Tarnished Copper Pipe* Expressed in Btu per (hour) (linear foot) (Fahrenheit degree difference between the pipe and surrounding still airat 70 F) Hot Wateb (Type K Copper Tube) Steam (Standard Pipe Size Pipe) Nominal Pipe Size (Inches) 120 F 150 F 180 F 210 F 227.1 F 297.7 F 337.9 F (5 psig) (50 psig) (100 psig) --FTemperature Difference Deo 50 80 110 140 157.1 227.7 267.9 h H 1 m 0.250 0.340 0.440 0.500 0.580 0.287 0.381 0.475 0.559 0.656 0.300 0.409 0.509 0.618 0.710 0.321 0.429 0.536 0.622 0.750 0.433 0.533 0.636 0.764 0.904 0.500 0.543 0.746 0.878 1.053 0.530 0.654 0.803 0.934 1.120 2 0.730 0.825 0.890 - 0.957 1.101 1.273 1.364 2H 3 3H 0.880 1.040 1.180 1.000 1.175 1.350 1.091 1.272 1.454 1.143 1.343 1.535 1.305 1.560 1.750 1.490 1.800 2.020 1.605 1.940 2.170 4 1.460 1.500 1.635 1.715 1.941 2.240 2.430 4H 5 6 8 1.600 1.840 2.400 1.812 2.125 2.685 1.980 2.270 2.910 2.071 2.430 3.110 2.131 2.387 2.740 3.310 ^ 2:465 2.770 3.210 4.050 2.650 2.990 3.440 4.370 Table 4. External Surface per Linear Foot of Copper Tubing Outside diameter 3^ in. greater than nominal size Tube Size (INCBE8) H 1 lH m Surface Abba (Sq Ft) 0.164 0.229 0.295 0.360 0.426 Tube Size (Inches) 2 2M 3 3H 4 Surface Area (Sq Ft) 0.556 0.687 0.818 0.949 1.080 Tube Size (Inches) 5 6 8 Subface Abea (Sq Ft) 1.342 1.604 2.128 Table 5. Area of Flanged Fittings, Square Feet" Nominal Pipe Size (Inches) Flanged Coupling 90 Deg Ft.t. Standard Extra Heavy Standard Extra. Heavy Long Radius Ft.t. Standard Extra Heavy . Tee Standard Extra Heavy Cross Standard Extra Heavy 1 1M IH 2 2H 0.320 0.383 0.477 0.672 0.841 0.438 0.510 0.727 0.848 1.107 0.795 0.957 1.174 1.65 2.09 1.015 1.098 1.332 2.01 2.67 0.892 1.084 1.337 1.84 2.32 1.083 1.340 1.874 2.16 2.76 1.235 1.481 1.815 2.54 3.21 1.575 1.925 2.68 3.09 4.05 1.622 1.943 2.38 3.32 4.19 2.07 ^ 2.53 3.54 4.06 5.17 3 3H 4 0.945 1.122 1.344 1.474 1.484 1.644 1.914 2.04 2.38 2.98 3.53 3.95 3.49 3.96 4.64 5.02 2.68 3.28 3.96 4.43 3.74 4.28 4.99 5.46 3.66 4.48 5.41 6.07 5.33 6.04 7.07. 7.72 4.77 5.83 7.03 7.87 6.95 7.89 9.24 10.07 5 1.622 2.18 4.44 5.47 5.00 6.02 6.81 8.52 8.82 10.97 6 8 1.82 2.78 2.41 3.77 5.13 6.98 6.99 9.76 5.99 7.76 7.84 10.64 10.08 8.56 11.09 10.55 14.74 13.44 13.75 18.97 10 3.43 5.20 10.18 13.58 12.35 15.60 15.41 20.41 19.58 26.26 12 4.41 6.71 13.08 17.73 16.35 18.76 19.67 26.65 24.87 34.11 * Including areas of accompanying flanges bolted to the fitting. previous example. If the system is operating at an overall efficiency of 55 percent, determine the monetary value of the annual heat loss from the line. Solution: The cost of heat per 1000 Mb supplied to the system = 1,000,000 X H-5 (dollars) -4- [13,000 (Btu) X 2000 (lb) X 0.55 (efficiency)] = $0,804. The total cost of heat lost per year = 0.804 X 171.1 (thousand Mb) = $137.56. I>ij>e:and Industrial Insulation 709 CONDUCTIVITY OF INDUSTRIAL INSULATIONS ' The conductivities of various materials used for insulating steam and hot water systems are given in Table 1. They are given as functions of the mean temperatures or the arithmetic mean of the inner and outer surface temperatures of the insulations. Fig. 1. Heat Loss through 1 In. Thick Pipe Insulation (Use with Table 6 for Various Insulations) HEAT FLOW CALCULATIONS . The heat losses through 1, 1J4> And 2-in. thick pipe insulation on various size pipes for various temperature differences between the pipe and the surrounding atmosphere up to 525 F, are shown in Figs. 1, 2, and 3. The actual thickness of many molded pipe coverings are not exactly 1 in. However, the loss through any given thickness of insulation can be obtained by interpolation.