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HEATINC VENTILATING AiR CONDITIONING GUIDE 1942 first cost is said to be justified on the basis of longer life expectancy. Wrought-iron pipe may be identified by the spiral line marked into each length, either knurled into the metal or painted on it in red or other bright color. Otherwise, there is little difference in the appearance of wrought iron and steel pipe, although microscopic examination of polished and etched specimens will readily disclose the difference. Cast Ferrous Pipe. There are now available several types of castferrous metal pipe made of a good grade of cast-iron with or without additions of nickel, chromium, or other alloy. This pipe is available in sizes from 1 in. to 6 in., and in standard lengths of 5 or 6 ft with external and internal diameters closely approximating those of extra strong wrought pipe. Cast ferrous pipe may be obtained coupled, beveled for welding, or with ends plain or grooved for the several types of couplings. It is easily cut and threaded as well as welded. The fact that it is readily welded enables the manufacturers to supply the pipe in any lengths practicable for handling. Alloy Metal Pipe. Steel pipe bearing a small alloy of copper or other alloying element and iron pipe bearing a small alloy of copper and molyb denum have been claimed to possess more resistance to corrosion than plain steel pipe and they are advertised and sold under various trade' names. Copper Pipe and Fittings. Owing to its inherent resistance to cor rosion, copper and brass pipe have always been used in heating, venti lating, and water supply installations, but the cost with standard dimen sions for threaded connections has been high. The recent introduction' of fittings which permit erection by soldering or sweating allows the use of pipe with thinner walls than are possible with threaded connections, thereby reducing the cost of installations. The initial cost of brass and copper pipe installations generally runs higher than the corresponding job with steel pipe and screwed connections in spite of the use of thin wall pipe, but the corrosive nature of the fluid conveyed or the inaccessibility of some of the piping may warrant use of a more expensive material than plain steel. The advantages of corrosionresisting pipe and fittings should be weighed against the correspondingly higher initial cost. COMMERCIAL PIPE DIMENSIONS The IPS dimensions of commercial pipe universally used at the present time conform to the recommendations made by a Committee of the A.S.M.E. in 1886. Pipe up to 12 in. in diameter is made in certain definite sizes designated by nominal internal diameter which is somewhat different from the actual internal diameter, depending on the wall thickness required. There are three weights of wrought iron and steel pipe commonly used, known as standard-weight, extra-strong, and double extra strong. Because of the necessity of maintaining the same external dia meter in all three weights for the same nominal size, the added wall thickness is obtained by decreasing the internal diameter. The term' full-weight, when applied to sizes below 8 in., means that the pipe is up to the nominal weight per foot. When applied to sizes between 8 and 12 in., inclusive, it often indicates that the pipe has the heaviest of several wall 342 CHAPTER 18. PIPE, FITTINGS, WELDING thicknesses listed. In sizes 14 in. and upward, pipe is designated by its outside diameter (O.D.) and the wall thickness is specified. While the demands for pipe for the heating and ventilating industry are reasonably well served by the standard-weight and extra-strong pipe, demands for pipe for higher pressures and temperatures in industry resulted in the use of a multiplicity of wall thicknesses for all sizes. Even in heating installations, the erection of piping by welding was deemed to Table 1. Dimensions of Schedules 30 and 40 and Standard Weight Pipe3 Diameter In. Weight per Ft, Lb Circum ference, In. Transverse Area, Sq In. Lbnoth of Pipe, Ft per 8a Ft Length y of Pipe 1 91Siz& J5 1 11 i -ca 1 a 11 1 13 J3 JS" w E-* Oh ac M W ie I SH *a3 2 a o 3 GO Ft 8 *2 030 Con- tainino 1 Cu Ft Lb peh Ft a1 3 2 3 a 2a '/ X y X 0.405 0.540 0.675 0.840 0.269 0.068 0364 0.088 0.493 0.091 0.622 0.109 0.244 0.424 0.567 0.S50 oooo 27 18 18 14 1.272 0.845 1.696 1.144 2.121 1.549 2.639 1.954 0.129 0.229 0.358 0.554 0.057 0.104 0.191 0.304 0.072 9.431 14.199 2533.775 0.125 7.073 10.493 1383.789 0.167 5.658 7.748 754360 0.250 4347 6.141 473.906 0.025 0.045 0.083 0.132 X i m IX 1.050 1.315 1.660 1.900 0.824 0.113 1.049 0.133 1.380 0.140 1.610 0.145 1.130 1.678 2.272 2.717 1.134 14 1.684 HH 2.281 HH 2.731 HA 3.299 4.131 5.215 5.969 2.589 3.296 4.335 5.058 0.866 1.358 2.164 2.835 0.533 0.864 1.495 2.036 0333 0.494 0.669 0.799 3.637 2.904 2.301 2.010 4.635 3.641 2.768 2.372 270.034 166.618 96.275 70.733 0.231 0.375 0.65 0.88 2 2H 3 3H 2.375 2.875 3.500 4.000 2.067 0.154 2.469 0.203 3.068 0.216 3.548 0.226 3.652 5.793 7.575 9.109 3.678 U'A 7.461 6.494 5.819 8 9.032 7.757 7.616 8 10.996 9.638 9.202 8 12.566 11.146 4.430 6.492 9.621 12.566 3355 4.788 7393 9.886 1.075 1.704 2.228 2.680 1.608 1328 1.091 0.954 1.847 1347 1345 1.076 42.913 30.077 19.479 14365 1.45 2.07 3.20 4.29' 4 5 6 8C 4.500 5.563 6.625 8.625 4.026 0.237 10.790 10.889 8 5.047 0.258 14.617 14.810 8 6.065 0.280 18.974 19.185 8 8.071 .0.277 24.696 25.000 8 14.137 12.648 17.477 15.856 20.813 19.054 27.096 25.356 15.904 24.306 34.472 58.426 12.730 20.006 28.891 51.161 3.174 0.848 0.948 4300 0.686 0.756 5.581 0376 0.629 7.265 0.443 0.473 11312 5.50 7.198 8.67 4.984 12.51 2315 22.18 8 10 10C .8.625 7.981 0.322 28.554 28.809 10.750 10.192 0.279 31.201 32.000 10.750 10.136 0.307 34.240 35.000 8 8 8 10 10.750 10.020 0.365 40.483 41.132 8 27.096 25.073 33.772 32.012 33.772 31.843 33.772 31.479 58.426 90.763 90.763 90.763 50.027 81385 80.691 78.855 8399 9.178 10.072 11.908 0.443 0355 0355 0355 0.478 0.374 0376 0.381 2378 21.70 1.765 35.37 1.785 34.95 1.826 34.20 12c 12 12.75C 12.750 12.09C 12.000 033( 0.375 43.773 49.562 45.0GC 50.70f 8 8 40.055 37.982 127.676 114.800 40.055 37.69 127.67C 113.097 12.87C 14.579 0.299 0399 0315 0315 1.254 49.70 1.273 49.00 ^Standard-weight wrought-iron pipe has approximately the same wall thicknesses and weights as contained herein for steel pipe. For exact dimensions, see American Standardfor Wrougfif-fron and WrougfuSUelPipe, A.S.A. B36.10. bThicknesses shown in bold face type are identical with thicknesses for Schedule 40 pipe of A-S.A. B36.10. warrant the use of pipe lighter than standard weight. For these reasons, a Sectional Committee on Standardization of Wroughl-Iron and WroughtSteel Pipe and Tubing functioning under the procedure of the American Standards Association was appointed to standardize the dimensions and materials of pipe. The pipe standard recommended by that sectional committee has set up several schedules of pipe including standard-weight and extra-strong thicknesses which are now included in Schedules 40 and 80, respectively. Dimensions and other useful data for standard-weight and extra-strong pipe are given in Tables 1 and 2. Table 3 from A.S.T.M. Specifications 343