Document VGdn020w8nnrdgqr39BydOV6w

American Society of Heating and Ventilating Engineers Guide, 1930 Table 10. Pipe Sizes for One-Pipe, Gravity, Low Pressure Steam Heating Systems, where-Equivalent Length of Run from Boiler or Source of Supply to Farthest Radiator Exceeds 200 Ft. Capacity in Sq. Ft. of Equivalent Radiation Based on 4 oz. Total Pressure Drop Pipe Size Inches orEquivalent Length Pipe prom Boileb to Farthest Radiator, Including Main and Riser. (See.Note 5.) Supply Main Dripped and Branches to Risen Dripped-- Steam and Condensate flowing in same direction. 100 Ft 200 Ft. 300 Ft. 400 Ft. 500 Ft. ~ 600 Ft AB C D E F G i 111 IX 245 79 173 65 141 56 122 49 110 46 100 m 2 380 771 269 546 220 446 190 386 165 345 155 315 -m 3 1270 2326 898 1645 734 1342 635 1163 568 1040 518 948 3X 4 3474 4914 2457 3475 2006 2828 1737 2457 1552 2196 1419 2011 5 9092 6429 6 14,924 10,553 5250 8618 4546 7462 4062 6669 3712 6094 8 31,066 21,967 17,935 15,533 13,880 12,682 10 56,689 40,085 32,730 28,345 25,334 23,144 12 90,985 64,336 52,530 45,492 40,660 37,145 Maximum Capacities Supply Risen Up-Feed Branches to Supply Risers and Radiators Not Dripped Radiator Valves and Vertical . Connections H Ji / 45 20 98 55 20 55 152 288 r 81 165 - 81 165 464 799 260 475 1144 1520 745 1110 -- 2180 -- ---- .-- -- -- --- Dht Return Main Wet Return Main Pipe ------ ---------------------- ---------------------------------- :---------:-------------------------------------:-----------------------------1------------------------------ Imtstka inches Equivalent Length of Run from Boiles to Foot of Farthest Riser in Feet Equivalent -Length of Run from Boiler to Foot of Farthest Ribeb in Feet 100 200 300 400 500 600 100 200 300 400 500 600 K L AT N 0 P Q R S T U V W i 460 412 368 320 275 227 1400 1000 820 700 640 580 IX 962 868 770 670 579 480 2400 1700 1390 1200 1080 990 m 1512 1362 1210 1058 909 757 3800 2700 2180 1900 1710 1570 . 2 3300 2960 2640 2300 1980 1630 8000 5600 4520 4000 3560 3240. 2X 5450 4900 4380 3800 3300 2770 13,400 9400 7600 6700 6000 5300 3 10,000 9000 8000 7000 6000 5000 21,400 15,000 12,500 10,700 9400 8500 3X 14,300 12,900 11,500 10,000 8600 7200 32,000 22,000 18,500 16,000 14,400 13,200 4 21,500 19,300 17,200 15,000 12,900 10,700 44,000 31,000 25,500 22,000 19,900 18,300 Cnnirldlu QT7 / American Societt of Heating and Ventilatino Engineers \ Not to be Reprinted Withvaipyngat, ava ^ Heating and Piping Contractor! National Aetociation f out Special Permission INSTRUCTIONS FOR USING TABLE 10 1. Radiator branches more than 8 ft. in length should be one size larger than shown in Column I. 2. These tables apply where pipes are properly reamed. No allowances tor defective ,, material or workmanship have been made. (Also see Tables 7 and 8). 3. Capacities based on l/i lb. condensation per square foot per hour equivalent radia-. tion and actual diameter of standard pipe. 4. Extra length to be added to straight run of pipe for various fittings and valves to determine equivalent length. (See Table 4). 348 Chapter 20--Piping for Steam Heating Systems INSTRUCTIONS FOR USING TABLE 10 (Continued) 5. Mains are to be proportioned according to the equivalent length of run from the boiler or source of supply to the farthest radiators supplied by the main. Determine equivalent length of run then use figures in corresponding Columns (B to G) for supply mains; (L to Q) for dry-return mains; (R to W) for wet-return mains for sizing the entire run. For example: If the distance from boiler or source of supply to the farthest radiator on the longest main should be 300 ft., all mains are to be sized from Column D; it 400 ft., Column E; if 600 ft., Column G. Risers are to be proportioned according to the equivalent length of run from the boiler or source of supply to the farthest radiator on each particular riser. Determine the distance to the farthest radiator then use the figures in the corre sponding Columns (B to G) for sizing each riser; providing the amount of radiation for that riser does not exceed amounts shown in Column H. Where riser capacities are found to be in excess of amounts in Column H, step up to necessary size indicated in that column. For example: If the distance from the boiler or source of supply to the farthest radiator on a supply riser is 300 ft., that riser is to be sized from Column D, providing the amount of radiation does not exceed the amount shown in Column H. If the amount exceeds that in Column H, use amounts shown in Column H for sizing that entire riser. If another riser taken from the same main as the one above is only 200 ft., this riser should be sized from Column C, providing the amount of radiation does not exceed that as shown in Column H. 6. The Guide Committee, 1930, after many check-tests, suggest that for practical purposes the pipe sizes on the usual heating system may be determined by using the pressure drop indicated by the longest main and riser on that system, neglecting the separate computations for each separate shorter fun. 7. Where it is necessary to drip a steam main, branch to riser or risers, same should be dripped separately into wet return. 8. Pitch of mains should be not less than l/f in. in 10 ft.; on horizontal branches to radiators and risers at least H in- in 10 ft. 9. In general it is desirable not to have a supply main smaller, than 2 in. in diameter. When the supply main is larger than 2J/ in. at the beginning, it is desirable that it shall not be smaller than 2J in. at the end. .................. is high and where all heaters are well above the water line, and where they do not have unusual condensing power, these sizes are permissible. The difference here is 4 oz., or approximately 8 in. Vacuum Pump Systems Fig. 5 shows a typical vacuum system of steam heating,'using a pump which handles both-the air from the system and the water of condensation from it. With such arrangements a wide difference in pressure between that in the supply main and that in the return main is permissible. A greater temperature range within the system than that obtainable, with vapor systems is insured. Heaters may be below the .water, line of the boiler, and even may be lower than the level of the pump, though such an arrangement generally should be -avoided. ................................... Table 15 gives approved pipe sizes for vacuum pump systems of com paratively small size, with a pressure drop not exceeding 4 oz., or a rise in the return connection of about 8 in., which, of course, easily can" be overcome by the vacuum pump. t Table 16 gives pipe sizes for larger systems in-which the vacuum pump is expected to maintain a greater suction, the allowable rise in. the return connection being about 16 in. 349