Document Y9mG62aY9y1vg0r4DLB6d5jB8

of and 1936American Society Heating Ventilating Engineers Guide, Fig. 1. Chart for Estimating Dollar Value of Heat Loss from Bare Iron Pipes; (See Table l)a oThis chart is based on 100 linear feet per 1000 hours. For fractions or multiples of these factors, multiply by proper percentage. heat equivalent to more than a ton of coal per year shows the necessity for insulating such surfaces. STEAM AND HOT WATER LINES The conductivities of various materials used for insulating steam and hot water pipes are given in Table 5. In this table the conductivities are given as functions of the mean temperatures or the mean of the inner and 654 36--Chapter Insulation of Piping Table 1. Heat Losses from Horizontal Bare Iron Pipes Expressed in Btu per linearfoot per degree Fahrenheit difference in temperature between the pipe and surrounding still air at 70 F Nominal Pm Size (Inches) H X l lX m 2 2X 3 3X 4 4X 5 6 S 10 12 120 F ' 50 F 0.543 0.660 0.791 0.979 1.09 1.34 1.58 1.88 2.13 2.36 2.60 2.87 3.39 4.32 5.32 6.25 Hot Water 150 F 180 F I 227.1 F 1 (5 Lb) Temperature Difference . 80 F 0.573 0.690 0.829 1.02 1.15 1.40 1.67 1.99 2.24 2.50 2.75 3.02 3.56 4.55 5.61 6.62 110 F 0.605 0.729 0.878 1.087 1.220 1.491 1.778 2.100 2.380 2.650 2.920 3.200 3.775 5.050 5.925 6.995 140 F 0.638 0.762 0.920 1.15 1.29 1.58 1.87 2.22 2.51 2.78 3.08 3.38 4.01 5.14 6.34 7.46 157.1 F 0.656 0.781 0.953 1.184 1.335 1.637 1.937 2.301 2.585 2.873 3.170 3.493 4.115 5.270 6.551 7.670 Steam 297.7 F (50 Lb) 227.7 F 0.742 0.886 1.084 1.345 1.520 1.866 2.215 2.641 2.972 3.312 3.655 4.030 4.755 6.120 7.592 8.900 337.9 F (100 Lb) 267.9 F 0.796 0.955 1.166 1.450 1.640 2.015 2.388 2.853 3.215 3.582 3.956 4.368 5.153 6.635 8.245 9.670 Table 2. Heat Losses from Horizontal Bare Copper Pipes Expressed in Btu per linear foot per degree Fahrenheit difference in temperature between the pipe at 210 F and surrounding still air at 70 F Nominal Pipe Size * (Inches) X X 1 ix m 2 Outside Diameter (Inches) 0.625 0.875 1.125 1.375 1.625 2.125 Temperature Difference 140 F 0.405 0.478 .0.550 0.623 0:695 0.841 Nominal Pipe . Size (Inches) 2X 3 3X 4 .5 6 Outride Diameter (Inches) 2.625 3.125 3.625. 4.125 5.125 6.125 Temperature Difference 140F 0.986 1.131 1.276 1.422 1.713 2.004 Table 3. Radiating Surface per Linear Foot of Pipe Nominal Pipe Size (Inches) X X 1 ix Surface Area (SqFt) 0.22 0.275 0.344 0.435 0.498 H Nominal 1 Pm Size | (Inches) i 2. 2X 3 3X 4. Surface Arba (SqFt) . 0.622 0.753 0.917 1.047 1.178 Nominal Pm Size (Inches) 5 6 8 10 12 Surface Arb^ (8q Ft) 1.456 1.734 2.257 2.817 3.338