Document wD5jEeNe1gY4KDpJ1bVZzNpmB

American Society of Heating and Ventilating Engineers Guide, 1932 . It is especially necessary with light-weight radiators so to anchorahd so to give freedom for expansion of the piping that no strain therefrom shall be allowed to distort the radiators. When expansion strains from ' the pipes are permitted to reach these light metal heaters they usually emit sounds of distress which are exceedingly troublesome. '\ FITTINGS Fittings for joining the separate lengths of pipe together are made in a variety of forms, and are either screwed or flanged; the former being generally used for the smaller sizes of pipe up to and including 3J^ in., and the latter for the larger sizes, 4 in. and above. Screwed fittings of large size as well as flanged fittings of small size are also made and are used for certain classes of work at the proper pressure. The material used for fittings is generally cast iron, but in addition to this malleable iron, steel and steel alloys are also used, as well as various grades of brass or bronze. The material to be used depends on the character of the service and the pressure. As in the case of pipe, there are several weights of fittings manufac tured, designed to be used with pipe of corresponding grade. These varia tions in weights are known as (1) low-pressure fittings for steam working pressures of 25 lb (cast-iron flanged only, sizes 4 in. and larger), (2) standard fittings for saturated steam working pressures of 125 lb, and extra heavy fittings for saturated steam working pressures of 250 lb. The latter fittings are suitable for cold water working pressures of 350,-lb and are usually tested to twice the steam working pressure, or 500 lb; cold hydrostatic. V'\ Screwed Fittings Screwed fittings include nipples or short pieces of pipe of varying lengths; couplings, usually of wrought iron only; elbows for turning angles of either 45 deg or 90 deg; return bends, which may be of either the close or open pattern, and may be cast with either a back or side outlet; tees; crosses; laterals or Y branches; and a variety of plugs, bushings, caps,, lock-nuts, flanges and reducing fittings. Reducing fittings as well as bushings, both of which are used in changing from one pipe size to another, may have the smaller connection tapped eccentrically to permit free drpin- age of the water of condensation in steam.lines or free escape of air in water lines. Flanged Fittings Flanged fittings are generally used in the best practice for connecting all piping above 6 in. in diameter. While screwed fittings may be used for the larger sizes and are satisfactory under the proper working con ditions, it will be found difficult either to make or to break the joints in these large sizes. The dimensions of elbows, tees and crosses for 125 lb cast-iron screwed fittings are given in Table 3, whereas the dimensions for 125 lb cast-iron flanged fittings are given in Tables 4 and 5. '. A special type of joint known as the Sarlun joint consists of a lip which is provided for welding to make the joint fluid tight, while mechanical 182 Chapter 11--Pipe, Fittings, Valves and Pipe Welding strength is provided by bolted flanges. Another type of pipe joint, the lap flange, -\s made by using loose flanges on lengths of pipe whose ends are lapped to give a bearing surface for a gasket or metal joint. VALVES Valves, like fittings, are usually either made with screwed or threaded ends or else are flanged for bolted connection to corresponding flanges on the pipe or fitting, in which case the flange and bolting arrangement should conform with the American Standard for flanged fittings of cor responding ratings. The material- used for valves of small size is generally brass or bronze for low pressures and forged steel for high pressures, while in the larger sizes Table 3. Dimensions of Elbows, 45 Deg Elbows, Tees, and Crosses (Straight Sizes) for 125 Lb Cast Iron Screwed Fittings A Nominal* Pips Size Center to End. Elbows. Tees and Crosses c Center to End, 45 Deo Elbows BB Length op Thread Min. Width op Band, Min. F Inside Diameter op Fitting Min. Max. GH Metal Thickness, Min. Outbids Diameter op Band. Min. x % X Vi 1 m IX 2vx 3 3X 4 5 6 8 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 0.580.67 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 i.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 0.5500.690 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 AU dimensions given in inches. 183