Document JEE03zvygJ3VRBx5rZOZb1GB

450 CHAPTER 31 1959 Guide Table 19 .... Dimensions of Flanged Cast-Iron and Steel Valves Notes for Table 19 from Anaien Stanford /or Paet^Foc* Dinauinii a] Perm* PIsivd ani WtlUni 8*4 ASA B18-10-1639. WKw dirodtficm* an out ziren, tba km either are not made or there ta in* sufficient denmad to wmnent the erpeme of onifieatteo- Female and groove Kant have bottom at groove in came plane u jbnft tift, *< center to contactsurface dimensions for these facing! are reduced by the amount of the raised lace. > *rK~ . pMiiTi. .Wipiatiiuv* ertwh refer to the primary service ratings in lb per eq in. of the connecting end flanges* tk connecting end fiangce of 175 lb valves are tbe tame as those on 250 lb valves. Th mtui rr*tn*riinf end flinfim for 400 lb valves S in. nse and smaller, are identical with those of 600 lb valves; Tj the contact surface to contact aurfaea dimeoxkua and connecting end Baages far 900 lb vahrse 1H in. eiae and smaller, are identical with those of 1500 lb valves. Table 20___ Thermal Stresses Due to Total Constraint Theme} Sirenet, Pti Choose, f Dog Steel Wrought too Cost Iron Brass or bronze Copp*, 20 3900 3800 1428 2760 40 7800 7600 2856 5520 60 11700 11400 4284 8280 80 15600 15200 5712 11040 100 19500 19000 7140 13800 * Far temperatures between SI and 400 F. 2980 59G0 8940 11920 14900 2700 5400 8100 10800 13500 Table 21 . Physical Properties for Determining Thermal Stress (Tmpcnrtwfi between 32 and 400 f) Steel Wrought Cost Iron Cop Alumper Coefficient ol Linear Expansion, a X 10*... 6.5 6.8 5.95 9.85 9.3 13.5 Modulus of Elasticity, E, psi X 10"*............... 30 28 12 14 16 10 Product of oB, psi......... 195 190 71.4 138 149 135 Bzam-pU: Tbe coefficient of expansion for steel -- 0.0300005 in-An. and the modulus of elasticity 30,000.000 pei. Therefore oB 195 psi. Table 22 .... Equations for Bending Stress and Deflection between Supports Type of Support Bending Stress, Pd 5 Deflection, Inches Y Single span (free ends)........................ Continuous line........ 8 = ---j-------S,, = 0'L.z5--Wj--U--D-- ,, 22.5 WL* Y~ El v 4.5 WL* Y- TT W Total weight (pipe, Quid, etc.) pounds per foot. D OD of pipe, inches. L Length of span, feet. E Modulus of elasticity, pounds per square inch. I Moment of inertia, (inches)4. / , OD, and ID in inches. Pipe, Fittings, Welding 451 Table 23 .... Application of Pipe, Tube, and Fittings for Heating and Air Conditioning Application Materials Commonly Utod Appflcofroa Materials Commonly Utod Chilled water Type K or L hard copper or black steel, Schedule 40 Cooling tower Type K or L hard copper, wrought iron, or black steel. Schedule 40 Underground water 2-in. and smaller 2)4-in. and larger Type K, soft copper or gal vanized steel, Schedule 40 (for corrosive soils, a coated steel pipe should be used) Type K, soft copper, cast iron. Class 150 or galvanized steel, Schedule 40 (for cor rosive soils, a coated steel pipe should be used) City water--inside building Type K or L, hard copper or galvanized steel. Schedule 40 Underground rain water con ductors Small installations Under paved areas Large installations 8-in. and smaller 10 to 24-in. 30-in. and larger 5 feet outside bldg, and under paving Vitrified clay or cast-iron soil Cast-iron soil Cast-iron soil XU or vitrified clay Vitrified clay or concrete Concrete Cast-iron soil XH Hot water heating* Refrigerant* Steam^ heating Supply 125 psi and less 125 to 250 psi Return pipe Ail sizes Receiver vent Ail sizes Sanitary* Small installations Waste: l)-in. and smaller 2-in. and larger Vents: 2^-in. and smaller Type K, hard copper or black steel, Schedule 40 Type K or L hard copper or black steel, Schedule 40 Black steel, Schedule 40, standard fittings Black steel, Schedule 40. For fittings see Table 8 Black wrought iron or steel. Schedule 40. Standard fit tings Galvanized wrought iron or steel, Schedule 40. Standard fittings Galvanized wrought iron or steel, Schedule 40 Cast iron Galvanized wrought iron or steel, Schedule 40 Interior rain water conduc tors Small installations Large installations Panel heating* Black or galvanized wrought iron or steel Schedule 40 Cast-iron soil XH, black or galvanized wrought iron or steel, Schedule 40 Type K or L soft copper. Black steel or wrought iron. Schedule 40 Large installations Waste: 2-in. and larger Vents: 2-in. and larger Gas (all kinds) All sizes Cast iron Cast iron Black steel. Schedule 40. Mal leable iron fittings * P*AcL hcati&t copper fittasgs should be soldered with #5-6 solder. Bteel fittings sluuld be welded. Ail underground feed and return lines buried is slab, should be equipped with fittings ss outlined for * Refrigerant fittings on copper pipe must be wrought copper. All welded fitting* should be tom. * House sewer to mein should be mat iron the fluid being carried. There is also the bending moment that may be caused by the flexure of the pipe. For this chap ter, however, the flexure loading will not be treated for the reason of complexity, as previously stated for the problem of expansion. Since hangers should always be designed to take the bend ing moment (including buckling) from the pipe, it is neces sary to design the hangers or supports for the maximum bending stress. Even with perfect support spacing there will be some sagging; therefore, the supports should be on a gradient if it is necessary to prevent pockets. Such a condi tion arises for condensate piping. Typical bending and deflection equations are given in Table 22 in order that supports can be properly sized, and if neces sary, pitched. These equations are typical beam equations. If more complex loadings exist, proper beam equations ran be applied. Such equations are found in standard texts on mechanics of materials. By application of the equations given in this section and the section on Expansion and Flexibility, it is possible to de termine the proper location and type of support for straight lines. The types are anchors and hangers. Anchors are used to guide the expansion (sliding anchors) or to fix the pipe. They are needed to take the stress out of the line and translate the stresses to the foundations. In that way all stress can be taken out of the ling before it can be transferred to such equipment as boilers or pumps. By manna of solid anchors, the anchors can be used to divide the piping into isolated sections that cannot transmit the stresses to other sections. Hangers are used to support the piping and to take out the bending stresses. They are of the spring, roller, or rod type. Such types generally allow the free movement of the pipe and yet maintain full support. The Code for Pressure Piping, ASA B31.1, has strict re quirements for the materials used in hangers and supports. The structural properties have a safety factor of five, and consequently there is little chance of failure due to a sud den change of load. There is a type of support for almost everv conceivable