Document vykVdpQO4EVrvqwMb8Lp7MBZZ

American Society of Heating and Ventilating Engineers Guide, 1930 On large installations, however, it may generally be assumed that welding is less costly than threading. It is to be remembered that a considerable saving in weight is made where welding is used, due to the elimination of heavy cast iron fittings. An indirect saving due to welding is that resulting from the lighter supports and hangers required. Non-Ferrous Piping A recent development in the pipe trades is the use of copper tubing with compression fittings. No threads are cut on the tubing, but the ends are expanded so as to fit against smooth spherical surfaces in the fittings, and are clamped there by a sleeve which may be screwed over the fitting, but which has no contact with the transported material inside the tube. The tube is thin enough to be bent readily, so that no elbow-fittings ordinarily are required. A typical example of this sort of piping and fittings is evidenced in the gasoline piping of any automobile. It is possible that piping and fittings of the non-ferrous type may prove most satisfactory for comparatively large sizes and for heavy pres sures and for rather high temperatures. Table 3. Standard Roughing-in Dimensions Angle Type Valves Size of Valve A" A" l' lA" 1A" 2" Tolerance H ADimension Steam and Hot Water Angle Valves and Union Elbows Effective Jan. 1,1926 2A" 3" 3A" 3 A" iA" ADimension Modolatino Valves Effective Jan. 1, 1926 2K" m" 3" m" 3A" iA" * A" ADimension Return Line Vacuum Valves Effective Jan. 1, 1925 3 A" The standardization of the Roughing-in Dimensions of Angle Steam and Hot Water, and Modulating Radiator Valves was made possible by the cooperation .of the Manufacturers Standardization Society of the Valves and Fittings Industry. 304 Chapter 18--Pipe and Fittings Expansion and Contraction In all piping systems which are subject to temperature variation pro vision must be made for adequate anchorages with expansion and con traction arrangements between them. In designing any system of steam or hot water piping the expansion for each straight run should be calculated and allowed for. All risers must be anchored and safeguarded so that the difference in length when hot from the length when cold shall not disarrange the normal and orderly provisions for drainage of the branches. It is especially necessary with ultra-modern light-weight radiators so Table 4. Dimensions of Elbows, 45 Deg. Elbows, Tees, and Crosses (Straight Sizes) A Nominal Pipe Size Center to End, Elbows, Tees and Crosses cBE Center to End, 45 Deg. Elbows Length of Thread Min. Width of Band, Min. F Inside Diameter of Fitting Min. Max, GH Metal Thickness, Min. Outside Diameter of Band, Min. A Vs A % l iA m 2 2A 3 m 4 5 6 f8 10 12 14 O.D. 16 O.D. 0.81 0.95 1.12 1.31 1.50 1.75 1.94 2.25 2.70 3.08 3.42 3.79 4.50 5.13 6.56 8.08 9.50 10.40 11.82 0.73 0.80 0.88 0.98 1.12 1.29 1.43 1.68 1.95 2.17 2.39 2.61 3.05 3.46 4.28 5.16 5.97 0.32 0.36 0.43 0.50 0.58 0.67 0.70 0.75 0.92 0.98 1.03 1.08 1.18 1.28 1.47 1.68 1.88 2.00 2.20 0.38 0.44 0.50 0.56 0.62 0.69 0.75 0.84 0.94 1.00 1.06 1.12 1.18 1.28 1.47 1.68 1.88 2.00 2.20 0.540 0.675 0.840 1.050 1.315 1.660 1.900 2.375 2.875 3.500 4.000 4.500 5.563 6.625 8.625 10.750 12.750 14.000 16.000 0.584 0.719 0.897 1.107 1.385 1.730 1.970 2.445 2.975 3.600 4.100 4.600 5.663 6.725 8.725 10.850 12.850 14.100 16.100 0.110 0.120 0.130 0.155 0.170 0.185 0.200 0.220 0.240 0.260 0.280 0.310 0.380 0.430 0.550 0.690 0.800 0.880 1.000 0.93 1.12 1.34 1.63 1.95 2.39 2.68 3.28 3.86 4.62 5.20 5.79 7.05 8.28 10.63 13.12 15.47 16.94 19.30 All dimensions given in incties. Dimensions for reducing elbows and reducing tees are given in Table 2 and Table 3, respectively. . 305 ^i