Document G5w6wkm7odGevYp1L8BG22prq

American Society of Heating and Ventilating Engineers Guide, 19^ Table 11. Maximum Allowable Capacities of Up-Feed Risers for Two.p Low Pressure Steam 1 Based on A. S. H. V. E. Research Laboratory Tests Pm 8ms Velocitt Feet peb Second Pbzssdbb Dbop Oonceb peb 100 Ft. So. Ft. Radiation Capacitt B.La. per Hour 4 20 23 27 14 30 35 m 38 41 34 42 43 1.78 1.57 1.48 1.33, 1.16 0.95 0.81 0.71 40 74 151 228 438 678 1129 1548 2042 9550 17,900 36,500 55,200 106,100 164,100 273,500 375,500 495,000 INSTRUCTIONS FOR USING TABLE 11 1. The capacities given in this table should never be exceeded on two-pipe risers. 2. Capacities based on 4 lb. condensation per square foot equivalent radiation and actual diameter of standard pipe. 3. All pipe should be well reamed and free from constrictions. Fittings should be up to size. (See Tables 7 and 8). It may be desirable in some cases to utilize a condensation pump rather than a vacuum pump where the heaters are too close to, or must be below, the boiler water line. Fig. 6 illustrates an approved hook-up for such a condition though, of course, the apparatus may be used with a wet return as well as with the dry return shown. It will be noted that each heater has a trap. When a condensation pump is used with a one-pipe system a false water line should be established sp that the sealing of each dry return against the others, so important with one-pipe systems, shall.be main tained. Sometimes, in this contingency, it is desirable to place a float trap on the end of each separate dry return connection to the pipe which supplies the pump-suction. There are a number of meritorious proprietary types of steam, vacuum return line, differential, and vapor heating systems,'which vary in certain particulars from the foregoing typical examples. These systems have been developed to meet the requirements of the newer architecture of modern building construction and are based on well established engineer ing principles of control for occupancy, wind and sun effect, zone demands, etc. Descriptions of these systems will be found in the catalog section of The Guide. 166 Chapter 10--Piping for Steam Heating Systems T/^LE Sizes for Two-Pipe Vapor15 Systems, where Equivalent Length ! " pim from Boiler or Source of Supply to Farthest 0F * Radiator does not exceed 200 Ft. Capacity in Sq. Ft. of Equivalent Radiation - n-An | nz, oer 200 RANCHES TO risers DaiFrt . and^on- SlTPPLT RlSZSS Up-Feed offledjieeUo"* 1163 1737 " 30 56 122 190 386 635 1129 1548 2042 *----- Branches to Sumi j jgpinfl and Radiators Not Drifted Return Ribers Da 26 58 95 195 395 700 1150 1700 3150 B 190 450 990 1500 3000 -- --- -- Wet Return Main P 700 1200 1900 4000 6700 10,700 ----- ---------- Dbt Return Main 320 670 1058 2300 3800 7000 10,000 Dsapnifeyfecpiraealntriteticsmuvalaakrreymsaoaskfteos.ucpaVppelayrctaiictnyau,l tchoenrneefocrtei-o--nu--ss--e-t-o-sizbee aosfrseacmoxensmizeenaasevua>lvwe | and trap used. Return horizontal runout to be not less than X In. / ANEBicANSocreTTOrHEATtKOAND VzimLATtNo Enqineebs ) Not to be Reprinted WlthCopyright, 1927 ^ Heating and Piping Contractors National Attoeiatim J out Special Permission INSTRUCTIONS FOR USING TABLE 12 1. Radiator branches more than 8 ft. in length should be one size larger than shown in>C2o. lTumhisn Dta.ble is for systems which are open to atmosphere or operate under slight pre3s.suTrheeoser ptaabrlteiaslavpapclyuuwmhewreithpoipuets uasree oprfovpaecrulyumreapmuemdp. s.No allowances for defective material or workmanship have been made. (Also see Tables 7 and 8). 4. Capacities based on 4 lb. condensation per square foot per hour equivalent rad5i.atEioxntraanldenagctthuatlodbiaemaedtdeerdotfostsatnradiagrhdt pruipne.of pipe for various fittings and valves to'd6.etWerhmeinree ietqisuivnaelceenstslaernygttoh.dr(iSpeea Tsaubplpely4)m. ain, 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. 7. Pitch of mains should be not less than 4 in. in 10 ft.; on horizontal branches to rad8ia- toI"rsgaennderarilsietrsisadtesleiraasbtle4noint .toinha1v0efat. supply main smaller than 2 in. in diameter. When the supply main is larger than 24 in. at the beginning, it is desirable that it shall not be smaller than 24 in* at the end. 167