Document zoy2oo4kQnr0pXdBwKLvVE65a

American Society of Heating and Ventilating Engineers Guide, 1929 If it is desired to determine the capacity of a pipe for any other length than 100 ft. or for any initial pressure other than 1 lb. Tables .2 and 3 are used. 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 opposite the required pressure indicated in Column 1. 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 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.? Solution.--From Table 2 it is found that the capacity of a 100 ft. 4 in. pipe with 1 lb. initial pressure and 2 oz. pressure drop, is 3475 sq. ft. Multiplying this value by 0.841 the constant for a 140 ft. length as given in Table 3 gives 2922 the capacity for the given conditions. 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 2457, the capacity of the 4 in. pipe with 1 lb. initial pressure and 1 oz. pressure drop. Multiplying 2457 by 1.03 the constant found in Column 2 of Table 3 for 2 lb. initial pressure gives 2531 as-the capacity of the 4 in. pipe with 2 lb. initial pressure and a pressure drop of 1 oz. per 100 ft. length. Example.--What is the capacity of a 140 ft. 4 in. pipe with 2 lb. initial pressure and a pressure drop of 2 oz.? Solution.--From Table 2 find 3475, the capacity of the 4 in. pipe with 1 lb. initial pressure and 2 oz. pressure drop. Multiplying 3475 by 1.03 the constant found in Column 2 for 2 lb. initial pressure and this by 0.841 the constant found under Column B the constant for 140 ft. length all as given in Table 3 gives 3010 as the capacity of the 4 in. pipe with 2 lb. initial pressure and a pressure drop of 2 oz. in the 140 ft. length. Should lengths other than those given in Column,.<4 Table 3 and under length of pipes in feet in Table 1 be desired the constant may be obtained from the formula in Column 4 Table 1. Example.--What would be the constant for 2500 ft. of pipe to be used either in Table 1 or 3? ' SoluEon.--The ^ 25(S) = or t^le constant t0 use,3- In determining the length of pipe used in any system, the actual length' must be increased for the various fittings, and valves, in determining the) equivalent length before applying any of the tables given. . Gate valves are recommended in all cases where the service calls for the valve to be either entirely closed or open. They should never be used forthrottling. Angle and globe valves should be used for throttling such as the by-pass valve in a pressure reducing outfit. 98 IIIChapter --Steam Heating Systems and Piping These tables are all based on the latest available scientific data with the idea of conserving pipe sizes as far as possible but without in any way jeopardizing proper operation. In this connection it has been assumed that all pipes will be reamed, that the piping will be properly pitched and in every respect will be of good construction and workmanship. It is recommended that pipes be not loaded beyond the capacities given. In using these tables special dare should be taken to read the headings describing the system, the pressure drop, etc., and particular attention should be given to the footnotes. Observation of these rules will make the effective application of these tables easy and save much time for the user. if Table 12. Pipe Sizes for Two-Pipe, Gravity, Vapor! Systems, where Equivalent Length of Run from Boiler or Source-of Supply to Farthest Radiator does- not exceed 200 ft. Capacity in Sq. Ft. of Equivalent Radiation Based on Total Pressure Drop of 1 oz. per 100 ft. Pipe Size Inches Supply Main Dripped and Branches to Risers Dripped Steam and Con densate flowing in same direction. AB SA 1 56 Supply Risers Up-Feed Branches to Supplt Risersand Radiators Not Dripped Return! Rttorh C 30 56 V 26 B 190 450 Wet Return Main P 700 Dry Return Main a 320 1M 122 190 122 190 58 990 1200 670 95 1500 1900 1058 2 386 VA 635 386 635 195 395 3000 -- 4000 6700 2300 3800 3 3'A 4 5 1163 1737 2457 4546 1129 1548 . 2042 -- 700 1150 1700 3150 -- -- -- 10,700 -- ____ 7000 10,000 ____ __ 6 7462 Different makes of supply and return valves, steam traps and other specialties vary as to capacity, therefore.use size as recommended for any particular make. Vertical connections to be of same size as valve and trap used. Return horizontal runout to be not less than ^ in. Copyright, 1927 / American Societi' orHeating and Ventilating Enoineebs \ Not to be Reprinted With- -\ Healing and Piping Contmdort National Auociation / out Special Permission *Radiator branches more than 8 ft. in length should be one size larger than shown in- CoL D. fThis table is for systems which are open to atmosphere or operate under slight pressure or partial vacuum without use of vacuum pumps. . Note I.--These tables apply, where pipes are properly reamed. No allowances for defective material or workmanship have been made. (Also see Tables 8 and 9). cumtciuuw actual diameter of standbaarsdedpipoen. H lb. condensation per square foot per hour equivalent radiation and cquivalent'length1 '(sfeTabled'f'1'* 10 8tra`ght mn of pipe for variou3 fittings and valves to determine it is nwxssaiy to drip a supply main, supply riser or branch to a supply riser, same should be dripped separately into a wet return. The drip for a vapor or vacuum system may be taken into a dry return through a steam trap. , rulsce.TMrs0a"t.fle~asft i/*j?inn. fi.nnfn1i0nsits.hould be not less than X in in 10 ft.; on horizontal branches to radiators and 99