Document ykKmZeZGYbZ8q7N84Ova2bnwD

496 CHAPTER 20 1951 Guide giving a perfect swing joint when connected to the vertical riser or radia tor connection, whereas the preferred connection does not give this swing without distorting the angle of the pipe. Runouts are usually made about 5 ft long to provide flexibility for movement, in the main. Offsets in steam and'return piping should preferably be made with 90-deg ells, but occasionally fittings of other angles are used, and in such cases the length of the diagonal offset will be found as shown in Fig. 38. Dirt pockets, desirable on all systems employing thermostatic traps, should be so located as to protect the traps from scale and sludge which Steam Heating Systems _ /Runout above floor --Riser/ Wall ,jne^ '''Swing''7' M..l...........R.a.d.ia.t.o.r..................\\0 ID'"* Runout below floor PLAN 497 Fig. 43. Flash Leg Installation foe 80 psi Maximum Steam WOBKING PRESSURE Table 13. Dimensions Applying to Fig. 43 Tram '- CONDENOATS FBB Ha., Lb AT 70 Psi HP SlDS i0Se0 & s tsa oc LP 8xdb i Plate Flash Lbo, IPS A Ft. In. In. In. In. F In. In. THICK NESS, In. 1 & <fat S 12 200 300 1 1 s1 21-80 31-70 1 1 6-20 a 0-15 4 4 36 36 83 i ui 83 i ui 700 1500 i 1 31-70 ! i 0-15 4 61-80 1 - i 0-15 5 3 6 83 4 6 10 4 1 u *. in i 2500 1 * 61-80 11 i 0-15 8 5 6 10 4 1 2 li 4000 " 8000 ou. H 61-80 2 1A 0-15 JL 6P80 21 lA 0-15 10 12 15000 21 A 61-80 21 lA 0-15 16 6 6 6 6 6 8 12 5 n 21 H 12 5 2 3 2 14 6 3 3 3 i t i I i i i i Fig. 44. Onb-Pipe Radiatob Connections will interfere with their operation. Dirt pockets are usually made 8 in. to 12 in. deep, and serve as receivers for foreign matter which otherwise would be carried into the trap. They are constructed as shown in Fig. 39 On vapor systems where the end of the steam main is dripped down into the wet-return, the air venting at the end of the main is accomplished by an air vent passing through a thermostatic trap into the dry-return line as shown in Fig. 40. On low pressure or vacuum systems, the ends of the steam mains are dripped and vented into the return through drip traps opening into the return line.' A float and thermostatic type trap is recommended for dripping , steam .mains and risers as indicated in Mgs. 41 and 42. The dripping of high pressure mains, or of equipment using high pressure steam into low pressure or vacuum returns,' is generally accomplished by the use of a flash tank or flash leg into which the high pressure trap is arranged to discharge. This tank provides the required space.for the flashing from high temperature condensate to low pressure steam to take place. The low pressure steam therein generated is passed directly to the low pressure steam mains, and the condensate is discharged through a second trap to the Fig. 45. Two-Pipe Top and Bottom Opposite End Radiator Connections Fig. 46. Two-Pipe Connections to Radiator Hung on Wall