Document peZ1yEL9063aQp97Da2Km5M6B

American Society of Heating and Ventilating Engineers Guide, 1928 capacities of branches to risers and radiators are based upon past ex perience and the Laboratory's findings. Table 9 is for small two-pipe systems, and is similar to Table 8. It gives values for parts of a two-pipe system. It was designed for laying out small two-pipe systems where the greatest equivalent length of run from the boiler to the farthest radiator does not exceed .200 ft. Table 10 is recommended for laying out small vapor systems. Table 11 and 12 were designed for larger one and two-pipe low-pressure gravity steam heating systems, respectively. These tables are based upon a 4 oz. pressure drop from the _ boiler to the farthest radiator and give capacities based upon such pressure drop for equivalent lengths ranging from 100 to 600 ft. These tables can be used for determining the size Table 10. 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 Pipe Size Inches Supply Main Dripped and Branches to Risers Dripped Steam and- Con densate flowing in same direction. AB X i 56 Supply Risers Up-Feed Branches to Supply Risers and Radiators Not Dripped Return Risers C D* E 30 190 56 26 450 Wet Return Main F 700 Dry Return Main G 320 m 122 m 190 122 190 58 990 1200 670 95 1500 1900 1058 2 386 2'A 635 3 1163 3H 1737 386 635 1129 1548 195 395 700 1150 3000 -- -- 4000 6700 10,700 -- 2300 3800 7000 10,000 4 2457 2042 1700 ........ --.... 5 4546 -- 3150 :----- -- 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. --i l., io-w / American Societt or Heating and Ventilating Engineebb \ Not to be .Reprinted With- v<op;Tignc, iv*/ | Heating and Piping Contraeton National Association / out Special Permission Radiator branches more than 8 ft. in length should be one size larger than shown in Col. D. tThis table is .for systems which are open to' atmosphere or'operate under slight pressure or partial vacuum without use of vacuum pumps. - Note 1.--These tables apply where pipes are properly reamed. No allowances for defective material or workmanship have been made. (Also see Tables 18. 19 and 20). " Notes.--Capacities based on diameter of standard pipe. lb. condensation per.square foot equivalent radiation and actual Note S.--Extra length to be added to straight run of pipe for various fittings and .valves to determine equivalent length. (See Table 6.) . ,. . Note 4--Where it is necessary 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.. Note 6.--Pitch of pipe should be not less than \i in. in 10 ft.; on horizontal branches to radiators, at least yi in. in 10 ft. 100 .. Chapter III--Steam Heating Systems and Piping- of pipe necessary to handle a given amount of radiation, either in a main, branch to the riser, riser, or radiator branch. Risers, or branches to risers or radiators, must not, however, be loaded above the maximum capacities for different parts of the system as given in the tables. Tables 13 and 14 are for sizing pipe for vapor systems where the equivalent length of run exceeds 200 ft. Table 13 is for systems up to 400 ft. equivalent length and is based upon a total pressure drop of 2 oz. from the source of steam supply to the farthest radiator. Table 14 is for larger systems where the equivalent length of run from the boiler or source of steam supply does not exceed 600 ft. It is based upon a total pressure drop of 4 oz. Risers and branches to risers and radiators should not be loaded above their maximum capacity as given in Columns F and G. Table 15 is a pipe sizing table for small vacuum pump systems where the equivalent length of run from the boiler or source of steam supply to the farthest radiator ranges from 100 to 600 ft. The table is based upon a total pressure drop in the entire equivalent length from steam supply. to farthest radiator of 4 oz. Up-feed risers, branches to risers and radiators should not be loaded beyond the maximum capacities given in Columns H and I. Table 16 is similar to Table 15 and is for larger systems where the equivalent length of run ranges up to 1200 ft. It is based on a total pressure drop of 8 oz. in the entire equivalent length. In designing any kind of a heating system it is well to avoid excessive pressure drop in any part of the system. While under proper design and good workmanship, higher drop may give good results, it is generally not considered good practice to exceed a drop of 1 oz. in 100 ft. equivalent' length. TYPICAL EXAMPLE Example in the use of the tables for. determining the size of pipe necessary in various parts of tlie vacuum pump system are shown in the accompanying diagram (Page 109): The equivalent length of run from the source of steam supply A to the farthest radiator supplied by any supply main (or the radiator on floor g Riser E) is between 600 and 800 ft.--therefore size the entire run according to Column H, Table 16, ob serving-Vote 4 as regards maximum capacity of up-feed supply risers given in Column K. Part of System Section of Pipe Radiation Supplied, Sq. Ft. Pipe Size, Inches Riser E ** Branch Supply Main " '" / tag e to / d to e c to d b to c a to b to Riser E . D to E C to D B to C A to B / 400 600 800 1000 1200 1400 1400 1600 2400 3200 4800 2H 2H 3 3 3H 3H 3H 4 5 6 p---------------------------------- The equivalent length of run from the source of steam supply A to the farthest radiator supplied by riser D is between 500. and 600 ft.--therefore size riser D and its branch, according to Column G observing Note 4 as regards maximum capacity of up-feed risers given in Column K. Note that the maximum allowable capacity of the 101