Document 7OgenKjoVYMLjpZXj2VzLE5DB

T able 9. Return Pipe Capacities Capacity Expressed in Square Feet o f Equivalent Direct Radiation ' (Reference to this table w lll be b y column letter Af through E ) This table la based on pipe size data developed through, the research Investigations of the American Society of Heating and Vbntilating Engineers. j' " . . . : CAPACITY OF RETURN MAINS AND RISERS HEATING VENTILATING AIR CONDITIONING GUIDE 1941 ofOrN^Oo'roi'OofNfoOoOoCoOoOOo 3 > BQQq 2 I1 J Ok QQ MI1M!M!i 8 MMIMMM >t oCqQ 5| J* xx *1 *- cs m t-- es 1.400 450 2.400 962 3,800 1,512 8,000 3.300 13.400 5,450 21.400 10,000 32.000 14.300 44.000 21,500 e & d u. 0C0O'0^0^'SCOOOO-'6OO-'MOMOQO is >HNN)tOOO X a ,28388888 . : : wh cn Tt oTcs aT 1 o & fe H*4NiOOi--lOCNl tHo j | d iff S u 8VN8N8O8i8O8N8NO88O8NO8 H^Tj'*'Oo''0(NOOr4 it & ilMOooM'OqOOoOOoOOqOQqOQoOQoO . ) , ! j: si 1 E- 700 1,200 1,900 4.000 6,700 10,700 16.000 22,000 OO'ONlO^OOOQO d OG o vhkj. io. cOWNrwohOn X8 |i ft5 ** a liCOtOSAOtOoOOrOti--^Q^TOft-'CO^NOQOOQQ^*: \} *I i csco'CoorwoH 'i "S & o IMQOOOOOQOnioNQe^NOOtoQOioOScsOSn .:| . } i wirom GO TO 00 i 1 >8 a. !:!:!:!:!:!:':!:!:!:!:! 248 520 822 1,880 3,040 5,840 7,880 11,700 1 */# Lb or Os ; ' Drop per 100Ft * fe: ,:m8o8o8ro8oo8r-8>o8o8in ,;. .,: S o S i jl "a 276 190 450 990 1,500 .3,000 MM: :j:s: i1ii i -- csmoorn -- -- o fO ^ CN ooooo CMOChOO v-Tfo' ): jj : ^^-vOOOOOOOO OOviONO'OO'OgiwOitaHt^rMtNON'QO <H(S0 0'wOHPC4S'f-*5I4>j0'0000 OOOQQ O--riOOv imOO -- CO j ij 8888888888 NN&ONNOONO v-r^-TT^'OO'OcNOoes wHv-tMO'O 'j j 190 450 990 1,500 3,000 ji O'OC-'OfOOOOQ OOiON'*NOHO^' . . . . w-4 v-l co in 190 . 450 7 990 1,500 3,000 j : |: j : t : ::: :j: Ss: ::: j ; :. : CHAPTER 14. PIPING FOR STEAM HEATING SYSTEMS Column C; radiator runouts and undripped riser runouts from Column L; up-feed risers from Column J; the main riser on a down-feed system from Column C (it will be noted that if Column H is used the drop would exceed the limit of Xi lb); the dry return from Column R; and the wet return from Column Q. With a Jje-lb drop the sizing would be the same as for Xi lb except that the steam main and dripped runouts would be sized from Column B, the main riser on a down-feed system from Column B, the dry return from Column 0, and the wet return from Column N. Table 10. Pipe Sizes for One-Pipe Up-feed System Shown in Fig. 2 Part of Ststeh Section of Pips Branches to radiators.. Branches to radiators.. Riser------------------------Riser------ -----------------Riser.................. ............ Riser............................... Riser-------- ------ ---------Branch to riser_______ Supply main-------------Branch to supply main Dry return main_____ Wet return main_____ Wet return main-........ Wet return main.......... ___ a to b b to c ctod d toe e tof f tog g to h h toj /to 4 ktom mton to p Radiation Supplied (SqFt) Theoretical Pipe em (Inches) Practical Pipe size (Inches) 100 2 2 50 IX ix 200 2 2 300 2X 2X 400 2X 2X 500 3 3 600 3 3 600 3X 3X 600 3 3 600 2X 3 600 IX 2 600 1 2 600 1 2 600 1 2 SOlR CEL^tJE] Fig. 2. Riser, Supply Main and Return Main of One-Pipe System Example S. Size the one-pipe gravity steam system shown in Fig. 2 assuming that this is all there is to the system or that the riser and run shown involve the longest run on the system. Solution. The total length of run actually shown is 215 ft. If the equivalent length of run is taken at double this, it will amount to 430 ft, and with a total drop of X lb the drop per 100 ft will be slightly less than Ho lb. It would be well in this case to use Hi lb, and this would result in the theoretical sizes indicated in Table 10. These theo retical sizes, however, should be modified by not using a wet return less than 2 in. while the main supply, g-h, if from the uptake of a boiler, should be made the full size of the main, or.3 in. Also the portion of the main k-m should be made 2 in. if the wet return is made 2 in. Notes on Gravity One-Pipe Air-Vent Systems 1. Pitch of mains should not be less than X in. in 10 ft. 2. Pitch of horizontal runouts to risers and radiators should not be less than X inT in 10 ft. Where this pitch cannot be obtained runouts over 8 ft in length should be one size larger than called for in the table.. 3. In general, it is not desirable to have a main less than 2~in. The diameter of the far end of the supply main-should not be less than half its diameter at its largest part. 4. Supply mains, branches to risers, or risers, should be dripped where necessary. 277