Document 65yY4JpkK87pp2gDkJ4o1b6GR

American Society of Heating and Ventilating Engineers Guide, 1931 _______________ ___ Table 1. Flow of Steam in Pipes P = loss in pressure in pounds. d = inside diameter of pipe in inches. L = length of pipe in feet. D = weight of 1 cu. ft. of steam. W -- pounds of steam per hour. VoW = 5220 PDd5 + 3.6' (>+)P = 0.0000000367 W* L Dd* Col. 1 Pm Size Pressure 522VwOunces Actual Nomina Internal Diameter Internal Area op Pipe Bq. Inches Col. 2 V1+iSm Steam Press. Gage Col 3 Length or PtPB Feet Cot, 4 V? 0.25 0.50 1.00 2 3 4 5 65.28 92.28 130.5 184.6 226.0 261.0 291.8 i IK IK 2 2K 3 3K 1.049 1.380 1.610 2.067 2.469 3.068 3.548 0.864 1.496 2.036 3.356 4.788 7.393 9.887 0.536 -1.0= 0.187 1.178 -0.5a 0.190 L.828 0.0 0.193 3.710 0.3 0.195 6.109 1.3 0.201 11.183 2.3 0.207 16.705 5.3 0.223 20 2.240 40 1-580 60 1.290 80 1.120 100 1.000 120 0.912 140 0.841 6 319.7 4 4.026 12.730 23.631 10.3 0.248 160 0.793 7 345.3 4K 4.506 15.947 32.134 15.3 0.270 180 0.741 8 369.1 5 5.047 20.006 43.719 20.3 0.290 200 0.710 10 412.7 6 6.065 28.886 71.762 30.3 0.326 250 0.632 12 452.0 7 7.023 38.743 106.278 40.3 0.358 300 0.578 14 488.3 8 7.981 50.027 149.382 50.3 0.388 350 0.538 16 522.0 9 8.941 62.786 201.833 60.3 0.415 400 0.500 20 583.6 10 10.020 78.854 272.592 75.3 0.452 450 0.477 24 639.3 12 12.000 113.098 437.503. 100.3 0.507 500 0.447 28 690.5 14 13.250 '137.880 566.693 125.3 0.557 600 0.407 32 738.2 16 15.250 182.655 816.872 150.3 0.603 700 0.378 40 825.4 Column I X 2 X 3 X 4 - lb. of steam 175-3 - 0.645 800 0.354 48 904.1 pipe for a given condition. 200.3 0.685 900 0.333 80 1167.2 -- 1.31b. press. -- 100 ft. equivalent length: 160 1650.7 130.5 X 3.710 X 0.201 X 1 - 07.2 lb. per hour. 97.2 X 4b s 388.8 sq. ft. equivalent radiation. 1000 0-316 1200 0.289 320 2334.5 Table 1 does not allow for entrained water in low-pressure steam, condensation in covered pipe and roughness in corn- 1500 0.258 480 2859.1 2000 . 0.224 Pounds per square inch gage 2.04 in. Vacuum, Mercury Column. bThe factor 4 is the approximate equivalent in square feet of steam radiation of 1 lb. of steam per boar 150 Chapter 10--Piping for Steam Heating Systems Unusual Conditions Mings which are heated intermittently or which have less radiation ,-s renuired for quick initial warming prior to occupancy, must have than 1 ^ pjpjng jn or(jer to compensate for the unusual demand on the piping per unit of radiation. GENERAL DATA ON PIPE SIZES The rate of flow of dry steam or steam with a small amount of water flowing in the same direction is in accordance with the general laws of as flow and is a function of the length and diameter of the pipe, the density of the steam and the pressure drop through the pipe. This rela tionship has been established by Babcock in the formula given at the too of Table 1. In columns 1, 2, 3 and 4 of this table, the numerical values of the factors for different pressure losses, pipe diameters, steam densities and lengths of pipe have been worked out in convenient form so that the steam flowing in any pipe may be calculated by multiplying together the proper factors in each column as shown in the example at the bottom of the table. Table 2 is a basic table giving the theoretical capacities of pipe in square feet of direct cast iron radiation (Based on 34 lb. steam per hour per square foot) and the resulting velocity in feet per second for various pressure drops in ounces per 100 ft. length of .pipe with an initial steam pressure of 1 lb. gage. This table was compiled from the values given in Table 1. In using Tables 1 or 2 the total pressure drop figured should never equal or exceed the initial pressure. Example: In a 3 in. pipe, what pressure drop is required in ounces per 100 ft. of length of pipe to supply steam to 2,014 sq. ft. of equivalent radiation? The initial steam pressure is 1 lb. gage. Solution: In Table 2, column for 3 in. pipe, find that steam for 2,014 sq. ft. of equivalent radiation will be supplied at 1 lb. initial pressure and a pressure drop of 3 oz. per 100 ft. length of run. Table 3 is to be used with Table 2 for calculating the capacity of a steam pipe, for other initial pressures and lengths when the capacity is known for 1 lb. pressure and 100 ft. length. To determine the capacity of any pipe under initial pressure other than 1 lb., multiply the capacity given in Table 2 by the pressure factor in Column 2, Table 3, opposite the required pressure indicated in Column 1. . Example: What is the capacity of a 100 ft! 4 in. pipe with 2 lb. initial pressure and pressure drop of 1 oz.? Solution: From Table 2, find 2,457, the capacity of the 4 in. pipe with 1 lb. initial pressure and 1 oz. pressure drop. Multiplying 2,457 by 1.03 the constant found in Column 2 of Table 3 for 2 lb. initial pressure gives 2,531 as the capacity of the 4 in. pipe with 2 lb. initial pressure and a pressure drop of 1 oz. per 100 ft. length. To determine the capacity for any length other than 100 ft., multiply the capacity given in Table 2 by the length factor in Column B, Table 3, opposite the required length in Column A. Example: What is the capacity of a 140 ft. 4 in. pipe with an initial pressure of 1 lb. and pressure drop of 2 oz. in the 140 ft.? 151