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138 Am. Soc. of Heat.-Vent. Engineers Guide. 1922 where fV = Weight of steam flowing through the pipe in lb. per minute. P = Difference of pressure between the two ends of the pipe. C -- Density of steam in lb. per cu. ft. d -- Actual inside diameter of pipe. L = Length of pipe in feet. This formula with the capacity expressed in sq. ft. of radiation on the basis of each sq. ft. of radiation with connected piping condensing 0.3 lb. of steam per hr. will be as follows: ^ 17400 VrSS . where R = Sq. ft. of radiation. Capacities of dry returns have been calculated by the Chezy formula for flow in open conduits which is expressed in the form Q=a cl/r s where Q -- Discharge in cu. ft. per sec. o= Wet area of pipe in sq. ft. r=>Hydraulic mean depth (areas of wet cross-section divided by the wet-perimeter.) c -- Constant from Kutter's formula. s -- Slope or grade. In the tables for one-pipe, two-pipe and vapor systems without the use of thermostatic traps the tables have been calculated on the basis of the water occupying % the area of the pipe while for vapor systems using thermostatic traps the capacity is based on water occupying 3/16 the area. All supply mains, branches to risers, when dripped, where steam and condensation flow in the same direction, and supply risers, (with the exception of up feed one-pipe risers) are based on a pressure drop of 1 oz. per 100 ft. length of pipe or equivalent. All supply mains, branches to risers, not dripped where condensation and steam are flowing in opposite directions and up feed one-pipe risers are based on a velocity of 16 ft. per sec. Branches to radiators 5 ft. in length or less are based on velocities from 10 to 19 ft. per sec. depending on the size of bfanch while branches to radiators 5 to 10 ft. in length are based on a velocity of approximately 10 ft. per sec. Wet returns are calculated on a drop of l/2 oz. per 100 ft. length of pipe or equivalent. Radiator valve sizes for one and two pipe gravity systems are based on standard practice. An allowance must be made for ells and fittings in the line of flow by adding the number of feet given in the table to the straight run of pipe to obtain the total equivalent length. Table V P Ol CU OI -- -- Jx"3 MMl^'OOvNi/tONf>>'O'<0Q00<d 9 3 o C w**" "*** *C** j oo -- oo*r ^iii omno WwjOHNwin-oHoNNNNnfmltN'fl _i v> H i^-oOo . ::::::::::: <= Je(S9 u J~S -.s'* '.m,,(0.s'O.oNOCOOOts(O'0O0 HHiqirttO - 2 .2 c9*c2 Oo jVC V '.ea cS aM 6.S *c .Ea .8c Sa luxQ.E c 3OOi-u0iOOO0O0OOO0OO *-TCM*V*<OOS __ SS I a 6 s .s-; 11 XQOu t2ooS8w E < <bH] sKfOa<. % m ucus 6t o. c 53 1/3 U1 Z oA >H C< 82 Q-5^ 2 -5.9 5 i^"o9o0iol OOS Q* ISSoSooS^8o8o -.j *>VoN Q EC !5 E <9 * ?-o -co g w "2 . JM *.S o 3 -oc 'Sco | 02 = 2 <gs2-ss %2 o *S SV aV ow .-3,0 Z -0 5 S fl g 8 d-a ' ''saa:! <->*2,,go zsh1-8-S S.S--3 o nOooooe a | q; 2 ` S2 go=g=> o.g -,, JVi .S v *-C0-C_E3 o ** *<nzo i 3 : ?o3 o O Socxos8 ' 2 S * | e a.=5-s-S O.CS ,*!*< c=/1 .!2!''' &(/) omOooooOoooOoOA Vt^t'^4OniOAOOOnOoOO'oOoOoooOOoo B'o S a "5 u > Ooor- .S " _ `t = "2 o 6 j l s s &s 8.i fue`Sc hs- :: "c go-g "ol1 o ii '3I'gg&^Cs/l ^^'"NN*MX99'Xin'CNON 31 i-i 139