Document 2N2LJp7OVX9ZVpLvKEDyv2Me5

Heating Ventilating Air Conditioning Guide 1939 Table 4. Heat Loss from Horizontal Tarnished Copper Pipe Expressed in Btu per hour per linear fool per degree Fahrenheit between the pipe and surrounding still air at 70 F Hot Water (Type K Copper Tube) Steam (Standard Pipe Size Pipe) Nominal. ' Pipe i 120 F Size (Inches) 150 F 180 F 210 F 227.1 F (5 Lb) Temperature Difference 297.7 F (50 Lb) 337.9 F (100 Lb) 'K k i IK iK 2 2K 3 3K 4 4K 5 6 8 50 F 0.250 0.340 0.440 0.500 0.580 0.730 0.880 1.040 1.180 1.460 1.600 1.840 2.400 80 F . 0.287 .0.381 0.475 0.559 . 0.656 0.825 1.000 1.175 1.350 1.500 L i 8i2 2.125 2.685 no f 0.300 0.409 0.509 0.618 0.710 0.890 1.091 1.272 1.454 1.635 1.980 2.270 2.910 140 F 0.321 0.429 0.536 0.622 0.750 0.957 1.143 1.343 1.535 1.715 2.071 2.430 3.110' 157.1 F 0.433 0.533 0.636 0.764 0.904 1.101 1.305 1.560 1.750 1.941 2.131 2.387 2.740 3.310 . 227.7 F 0.500 0.543 0.746 0.878 1.053 1.273 1.490 1.800 2.020 2.240 2.465 2.770 3.210 4.050 267.9 F 0.530 0.654 0.803 0.934 1.120 1.364 1.605 1.940 2.170 2.430 2.650 2.990 3.440 4.370 linear foot of pipe. Table 5 gives these areas for various standard pipe sizes, and Table 6 for copper tubing, while Table 7 gives the area in square feet for flanges and fittings for various standard pipe sizes. . Very often, when pipes are insulated, flanges and fittings are left bare due to the belief that the losses from these parts are not large. However, the fact that a pair of 8 in. standard flanges having an area of 2.41 sq ft Table 5. Radiating Surface per Linear Foot of Pipe Nominal Pipe Size (Inches) K: K 1 iK IK Surface Area (Sq Ft) 0.22 0.275 0.344 0.435 0.498 Nominal Pipe Size (Inches) 2 2K 3 3K 4; Surface Area (Sq Ft) ' 0.622 0.753 h.917 1.047 1.178 Nominal Pipe Size (Inches) 5 6 8 10 12 Surface Area (Sq Ft) 1.456 1.734 2.257 2.817 3.338 Table 6. Radiating Surface per Linear Foot of Copper Tubing (Inches) K K. . l ' IK IK Surface Area (Sq .Ft) 0.164, 0.229 0.295 0.360 0.426 Tube Size . (Inches) '2 2K. 3 3K 4 Surface Area (Sq Ft) 0.S56 0.687 0.818 0.949 1.080 Tube Sim . (Inches) i -5 6 8' Surface Area (Sq Ft) 1.342 1.604 2.128 ' Chapter 39. Piping and Duct Insulation Table 7. Areas of Flanged Fittings, Square Feet11 Nominal Pipe Size (Inches) i IK IK 2 2K 3 3K 4 4K 5 6 8 10 12 . Flanged Coupling -90 Deg Ell Long Radius Ell Tee Cross Standard Extra Heavy Standard Extra Heavy Standard Extra Heavy Standard Extra Heavy Standard Extra Heavy 0.320 0.438 0.795 i.015 0.892 1.083 1.235 1.575 1.622 2.07 0.383 0.510 0.957 1.098 1.084 1.340 1.481 1.925 1.943 2.53 0.477 0.727 1.174 1.332 1.337 1.874 1.815 2.68 2.38 3.54 0.672 0.848 1.65 2.01 1.84 2.16 2.54 3.09 3.32 4.06 . 0.841 1.107 2.09 2.57 2.32 2.76 3.21 4.05 4.19 5.17 0.945 1.484 2.38 3.49 2.68 3.74 3.66 5.33 4.77 6.95 1.122 1.644 2.98 3.96 3.28 4.28 4.48 6.04 5.83 7.89 1.344 1.914 3.53 4.64 3.96 4.99 : 5.41 7.07 7.03 9.24 1.474 2.04 3.95 5.02 4.43 5.46 - 6.07 7.72 7.87 10.07 1.622 2.18 4.44 5.47 5.00 6.02 6.81 8.52 8.82 10.97 1.82 .2.78 5.13 6.99 5.99 7.76 7.84 10.64 10.08 13.75 2.41 3.77 6.98 9.76 8.56 11.09 10.55 14.74 13.44 18.97 3.43 5.20 10.18 13.58 12.35 15.60 15.41 20.41 19.58 26.26 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. would lose, at 100 lb steam pressure, an amount of heat equivalent to more than a tori of coaLper year'shows the necessity for insulating such surfaces. HEAT LOSSES FROM INSULATED PIPES The [conductivities of various materials used for insulating steam and hot water pipes are given in Table 8. In this table the conductivities are given as functions of the mean temperatures or the mean of the inner and outer surface temperatures of the insulations. This method of stating conductivities makes it possible to readily calculate the heat loss through single or compound sections. It should be emphasized that the conduc tivities given in Table 8 for the various insulations are the average of Table 8. Conductivities (k) of Various Types of Insulating Materials for Medium and High Temperature; Pipes Types op Insulating Material . 100 F 85 per cent Magnesia Type................ :__ L_.:. ft. 425 Corrugated Asbestos Type.______ 1.......... ,o:.53o (4 Plies per 1 in', thick) Corrugated Asbestos Type. ... .(.... ... .. .. 0.480 (8 Plies per 1 in. thick) Laminated Asbestos Type................ :__ 0.360 (30-40 Laminations'per 1 in. thick) Laminated Asbestos Type.............. 0.545 (20 Laminations per X in. thick) Rock Wool Type ........... ...................... . 0.350 High Temperature Type.____ ...................... .. 0.515 (Diatomaceous Earth and Asbestos) Brown Asbestos Type.______ ____ ;.............. 0.600 (Felted Fibre) . Mean Temperature 200 F 0.465 0.650 0.555 300 F 0.505 0.770 0.630 400 F 0,550 0:890 0l705 0.415 0.470 0(525 0.605 0.665 0.725 0.410 0.470 0(530 0.545 0.575 0:605 0.640 0.675 0.715 500 F 0.590 0.585 0.785 0.590 0.635 0.750 R. H. Heilman, Mechanical Engineering, Vol. 46 (1924),p.593\