Document MGQo2mvrrNOz0O4DnnppQ03yM

516 CHAPTER 28 1946 -Guide Table 5. Areas of Flanged Fittings, Square Feet Nominal Pipe Size (Inches) i IK IK 2 2K 3 3K 4 4K 5 6 8 10 12 Flensed Coupling 90 Deg Ell Long Radius Et-t. Tex ^ Cooes Standard Extra Heavy Standard Extra Heavy Standard Extra Heavy Standard Extra Heavy Standard Extra Heavy 0.320 0.383 0.477 0.672 0.841 0.945 1.122 1.344 1.474 1.622 1.82 2.41 3.43 4.41 0.438 0.795 1.015 0.892 1.083 1.235 1.575 1.622 2.07 0.510 0.957 1.098 1.084 1.340 1.481 1.925 1.943 2.53 0.727 1.174 1.332 1.337 1.874 1.815 2.68 2.38 3.54 0.848 1.65 2.01 1.84 2.16 2.54 3.09 3.32 4.06 1.107 2.09 2.57 2.32 2.76 3.21, 4.05 4.19 5.17, 1.484 2.38 3.49 2.68 3.74 3.66 5.33 4.77 6.95 1.644 2.98 3.96 3.28 4.28 4.48 6.04 5.83 7.89 1.914 3.53 4.64 3.96 4.99 5.41 7.07- 7.03 9.24 2.04 3.95 5.02 4.43 5.46 6.07 7.72 7.87 10.07 2.18 4.44 5.47 5.00 6.02. 6.81 8.52 8.82 10.97 2.78 5.13 6.99 5.99 7.76 7.84 10.64 10.08 13.75 3.77 6.98 9.76 8.56 11.09 10.55 14.74 13.44 18.97 5.20 10.18 13.58 12.35 15.60 15.41 - 20.41 19.58 26.26 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. 1 each type of material, also, that in the use of conductivity all variables due to differences in thickness, pipe sizes, and air conditions are eli minated. Individual manufacturer's materials will, of course, vary in conductivity to some extent from these values. The heat losses through 1, i}/2, and 2-in. thick 85 per cent magnesia type of insulation for temperature differences between the pipe and the surrounding atmosphere up to 280 F are shown in Figs. 1, 2, and 3. Standard thicknesses of 85 per cent 'magnesia pipe covering are not exactly 1 in. However, the loss through any given thickness of insulation can be obtained by interpolation. Also, the losses through any of the insulations given in Table 6 can be obtained by multiplying the losses obtained from Figs. 1, 2, or 3 by the factors given in Table 7. . Pipes operating at high temperatures are frequently insulated to the best advantage by combining a high temperature insulation near the pipe with a moderate or low temperature insulation around it as an outer Table 6. Thermal Conductivity (k) of Various Type Pipe Insulations for Medium and High Temperature Pipe2 Expressed in Biu per (hour) {square foot) {Fahrenheit degree temperature difference per.inch) Types of Insulating Materials Density Lb/Cu Ft Temp. Range FMean Temperature. Deg *of Accepted Use 100 200 300 400 500 85% Magnesia---Type.................. 13-15 Corrugated Asbestos--Type 4 Ply per 1 in.............................. -11--13 6 Ply per 1 in-........:................... 15-17 8 Ply per 1 in.............................. 18-20 laminated Asbestos--Type (35-40 laminations per 1 in.)___ 30-35 Mineral Wool--Type..................... 10-15 Diatomaceous Silica--Type......... 25-30 Brown Asbestos Fiber--Type.. . 13-15 Up to 600 F 0.41 0.45 0.48 0.52 Up to- 300 F 0.57 0.68 0.80 Up to 300 F 0.51 0.59 0.69 Up to 300 F 0.49 0.57 0.65 Up to 700 F Up to 800 F Up to 1900 F Up to 1200 F 0.39 0.44 0.49 0.54 0.40 0.45 0.50 0.55 0.63 0.66 0.69 0.72 6.75 0.34 0.39 0.44 0.49 0.54 `Average values from various laboratories for insulating materials of various manufacturers. TEMP 01FF FROM PIPE TO ROOM, F DEG Fig. 1. Heat Loss Through 1 In. Thick 85 per cent Magnesia Type Covering layer. By this method an efficient material may be used for each of the two temperature ranges encountered. In calculating the heat loss through such a combination the mean temperature of each layet must be determined along with the thickness of each. This is readily done in