Document B8n1mnKrb8DN43qrd4pb9O4eE

American Society of Heating and Ventilating Engineers Guide, 1932 Table 13. Pipe Sizes for Two-Pipe Vapor Heating Systems, where Equivalent Length of Run from Boiler or Source of Supply to Farthest Radiator Exceeds 200 Ft. Capacityin Sg. Ft. Equivalent Radiation Based on 2 oz. Total Pressure Drop Equivalent Length or Pipe prom Boiler to Farthest Radiator. Including Main and Riser. (See Note 6.) SuddIv Main Dripped and Branches to Risen Dripped-- Steam and Condensate Sowing in same direction. Maximum Capacities 100 Ft 200 Ft. 300 Ft. 400 Ft. Su^Iy^Risere Branches to Supply Risen and Return Risers Radiators Not Dripped A.) % i l Pi m 2 2H 3 3Pi 4 5 6 8 10 12 B 79 173 269 546 898 1645 2457 3475 " 6929 10,553 21,967 40,085 64,336 C 56 122 190 386 635 1163 1737 2457 4546 7462 15,533 23,345 45,492 D. 46 100 155 315 518 948 1419 2011 3712 6094 12,682 23,144 37,145 B 39 87 134 273 449 822 1228 1738 3214 5276 10,983 20,043 32,168 F Ga H 30 190 56 26 450 122 58 990 190 95 1500 386 635 1129 1548 2042 195 395 700 1150 1700 3150 3000 __ _ ____ -- 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 hori zontal runout to be not less than ^ In. Dry Return Main Pips Sms Inches Equivalent Length or Run prom Boiler to Farthest Radiator in Feet Wet Return Main Equivalent Length or Run rttou Boiler to Farthest Radiator in Feet / i iPi iPi .2 2Pi 3 3^ 4 100 / .355 745 1173 2680 4300 7800 11,100 16;700 200 k/ 320 670 1058 2300 3800 7000 10,000 15,000 300 L 285 : 595 943 2140 3470 6250 8800 13,400. 400 M 248 520 822 1880 3040 5480 7880 11,700 100 N 1000 1700 2700 5600 9400 15,000 22,000 31,000 200 0 700 1200 1900 4000 6700 10,700 16,000 22,000 300 P 580 990 1570 3240 5300 8500 13,200 18,300 400 <? 500 850 . 1350 2800 4700 7500 11,000 15,500 ^. 0__ / American Society o? Heating and Ventilating ENGmBBra 1 Not to be Reprinted Wifht<opyri(iit, lszy y Heating and Piping Contractors National Auoddtfon / out Special Permission 152 yrr Chapter 9--Steam Heating Systems and Pipe Sizes INSTRUCTIONS FOR USING TABLE 13 - . aj4 Radiator branches more than 8 ft. in length should be one size larger than shown in Column G. 2. This table is for systems which are open to atmosphere or operate under slight pressure or partial vacuum without use of vacuum pumps. 3. These tables apply where pipes are properly reamed. No allowances for defective material of workmanship have been made. (Also see Tables 7 and 8). 4. Capacities based on M lb. condensation per square foot per hour equivalent radiation and actual diameter of standard pipe. 5. Extra length to be added to straight run of pipe for various fittings and valves to determine equivalent length. (See Table 4). 6. 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 E) for supply mains; (/ to M) for dry-return mains; (N to Q) 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; if 400 ft., Column E. Supply and return 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 riser. For supply risers determine the distance from the boiler to the farthest radiator served by that riser then use the figures in the corresponding Columns (B to E) for sizing each supply riser; providing the amount of radiation for that riser does not exceed amounts shown in Column F. Where supply riser capacities are found to be in excess of amounts shown in Column F, 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 F. If the amount exceeds that in Column F, use amounts shown in Column F for sizing that entire riser. If another riser taken from the same main as the one indicated 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 F. For return risers determine the equivalent length of run in feet from the top of each riser to the boiler, then use the figures in the corresponding Columns (J to M) for sizing each riser. 7. For practical purposes the pipe sizes on the usual heating system may be deter mined by using the pressure drop indicated by the longest main riser on that system, neglecting the separate computations for each separate shorter run. 8. Where it is necessary to drip a supply main or a supply riser or a branch to a supply riser, same should drip separately into a wet return. The drip'for a vapor or vacuum system may be taken into a dry return through a steam trap. 9. Pitch of mains should be not less than pi in. in 10 ft.; on horizontal branches to radiators and risers at least in. in 10 ft. 10. In general it is desirable not to have a supply main smaller than 2 in. in diameter. When the supply main is larger than 2J4 in. at the beginning, it is desirable that it shall not be smaller than 23^ in. at the end. -- 153