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API 608:2008 pdf download

API 608:2008 pdf download.Metal Ball Valves-Flanged,Threaded and Welding Ends.
5.5 BaIl-stem Design and Construction
5.5.1 The valve shall be designed to insure that if a failure occurs at the stem-to-ball connection or of the stem itself within the pressure boundary, no portion of the stem is ejected by internal pressure.
5.52 The torsional strength of both the stem-to-ball connection and the portion or the stem within the pressure boundary (below top of packing) shall exceed the torsional strength of the stem portion above the pressure boundary (above the top of the packing) by at least 10%.
5.5.3 The stem and the ball-to-stem connection shall be designed such that no permanent deformation ojrs and no failure of any part occurs when a force applied to the lever or gear operator handwheel produces a torque equal to the greater of
— 15 ft-lbs (20 N-ni), or
— twice the manufacturers maximum published torque.
The manufacturers maximum published torque shall be based upon clean, dry air service at the maximum differential pressure rating of the valve.
5.6 Ball Construction
Ball shall have a cylindrical bore and shall be of solid. one-piece construction. Other constructions, such as hollowtype, cored cavtiy, or sealed cavity may be furnished only if agreed loby the purchaser.
5.7 Packing Glands and Gland Bolting
5.7.1 Adjustable packing glands shall be accessible for re-sealing stem packing without the disassembly of valve paris or operator parts
5.7.2 Packing glands that are threaded into bodies or covers or onto stems shall not be used for valve sizes greater than NPS 3 (DN 80) unless otherwise specified by purchaser. (See Figure 1 and Figure 2 for parts identification.)
5.7.3 Vertically split glands shall not be used.
5,7.4 When used, gland bolts shall pass ttwough holes in the packing wand. The use of open slots is not permitted on any portion of the packing wand,
5.7.5 Packing gland bolts shall be designed so that the bolt stress shall not exceed ?3 of the ultimate tensile strength of the bolting material when compressing packing material to a compressive stress of 5500 PSI (38 Mpa) at
100 F (36 C).
5.8 Operation
5.8.1 Unless otherwise specified on the purchase order, manually operated valves shall be equipped with lever-type handles.
5.8.2 Gear operators shall be fitted with handwheels and shall be sized to comply with the requirements of 5.8.3
5.8.3 Unless otherwise specified by the purchaser, the length of the lever handle or the gear ratio, efficiency and handwheel diameter of gear operators shall be designed so that the required input force to fully open and close valve shall not exceed 80 lb (360 N) when operating valve at manufacturer’s maximum published torque as described in 5.5.3.
5.8.4 Valves shall be cdosed by rotating the closure device (lever or handwheel) in a clockwise direction.
5.8.5 Position stops shall be provided for both flly open and fully closed positions of valve.
5.8.6 Handwheels on manual gear operators shall be marked to indicate the direction of opening and/or closing.
5.8.7 Lever type handles shall be parallel to the ball bore, so that lever always indicates ball bore position. If the
purchaser specifes round or oval direct-mounted handwheels, a permanent means of indicating ball bore position
shall be included in handwheel design.
5.8.8 An indication of the position of ball bore of the valve shall be integral with the valve stem. This indication may
be by permanent marking to the top of the stem, or by shape of exposed stem portion.
5.8.9 Levers, handwheels and other operaling mechanisms shall be fttd so that they may be removed and
replaced without affecting the integrity of the stem seal(s), body seal(s) or stem retention means.
5.8.10 Lever or manual gear operators shall be designed so that the lever or gear operator cannot be assembled to
the valve other than in the correct configuration to indicate open and closed positions.
5.8.11 When specifhed in the purchase order, valves shall be furnished with a lockable device that accepts a
purchaser-supplied padlock that llows the valve to be locked in both the flly open and flly closed positions. The
lockable device shall be designed such that a lock with a
5/16-in. (8-mm) diameter shank, not more than 4.0 in.
(102 mm) long can be inseted direty through hole(s) in lockable device and locked. Provision for lockable device is
permitted, even when not specifed on purchase order.
5.8.12 Position stops integral with packing gland, gland fiange or gland blling shall not be used.
5.9 End Flange Face Interruptions
5.9.1 Ring shaped radial gaps in the faces of end flanges of flanged ball valves, located in the sealing surface of a centered ASME B16.20 spiral-wound gasket, shall not exceed 0.030 in. (0.75 mm): see dimension b on Figure 1. An example of this condition is the radial gap that exists between the outer diameter of a body insert and the inner bore
of the body end flange of a valve as shown in Figure B.1.
5.9.2 For ball valves designed with a body insert as shown in Figure B.1, with a gasket seating face outer diameter located within the sealing area of a centered ASME B16 20 spiral-wound gasket, the body insert flange face shal not protrude beyond the valve body end flange face. The body insert fiange face shall not be recessed below the body end flange face by more than 0.010 in. (0.25 mm). See dimension a on Figure 1.
5.10 Valve Shell Joints
5.10.1 Nut and bolt head bearing surfaces of shell parts assembled by bolting shall be perpendicular to the centerdine of tapped or cdlearance holes for the fasteners within土1.0 degree.


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