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API STD 594:2010 pdf download

API STD 594:2010 pdf download.Check Valves: Flanged, Lug, Wafer,and Butt-welding.
5.4 External Bolts and Threaded Holes
5.4.1 Bolts and threaded holes with a diameter 1 in. or smaller shall have coarse (UNC) threads. Those larger than
1 in. diameter shall be of the eight-thread series (8 UN). Bolt threads shall be Class 2A, and nut threads shall be
Class 2B. Threads shall conform to ASME Bi .1.
5.4.2 For bolts 1 in. diameter or smaller, threaded body-flange bolt holes shall be drilled and tapped according to the requirements for coarse thread series Class 2B in ASME Bi .1. For bolts larger than I in. diameter, such holes shall be drilled and tapped according to the requirements for eight-thread series Class 2B in ASME Bi .1.
5.4.3 For Type ‘B’ valves, cover flange bolts shall be continuously threaded stud bolts with heavy, semifinished hexagon nuts conforming to the requirements of ASME B18.2.2. Hex bolts or cap screws conforming to ASME B18.2.1 may also be used for DN 65 (NPS 21/2) and smaller valves. Hex bolts and cap screws shall be suitable for external wrenching only.
5.5 Flow Indication
The valve body shall be furnished with a clearly visible cast, forged, machined-in, or die-stamped arrow to indicate the direction of flow through the valve.
5.6 Gasket Surface
Fasteners in the flange seating surface shall be recessed to or below the flange gasket level. Interruptions in the seating area of a centered ASME B16.20 spiral-wound gasket for valve sizes DN 150 (NPS 6) and larger shall not exceed the limitations given in Figure 1. The permissible surface interruptions on smaller size valves shall be as agreed between purchaser and manufacturer but shall not exceed 50 % of the gasket seating width.
NOTE The degree of interruption may affect the sealability of a spiral-wound gasket.
6 Material
6.1 Bodyand Cover
The body of Type ‘A’ valves and the body and cover of Type ‘B’ valves shall be made of a material conforming to a purchaser selected material specification listed in the applicable ASME standard as referenced in 4.1.
6.2 Plate and Disc
Plate or disc shall be made of a material whose corrosion resistance is greater than or equal to that of the valve body.
6.3 Cover Gasket (Type ‘B’ Valves)
6.3.1 The cover flange gasket shall be:
— solid metal, corrugated or flat;
— filled metal jacketed, corrugated or flat;
— metal ring joint;
— spiral-wound metal gasket with filler and a centering/compression nng;
— spiral-wound metal gasket with filler, to be used in a body to cover joint design that provides gasket compression control.
9.1.1 Unless otherwise specified in the purchase order, the external surfaces of valve bodies shall be painted with the following colors:
carbon and low-alloy steel—aluminum,
— ductile iron—green,
— cast iron—black,
— nonferrous and austenitic stainless steel—none.
9.1.2 The machined surfaces of materials that are not rust resistant shall be coated with easily removable rust preventive.
9.1.3 All coatings and/or paints shall not contain lead.5
9.2 Valve Openings
9.2.1 Except for the ends of small, individually packaged valves, valve ends shall be covered to protect the gasket surfaces and valve internals during shipment and storage. The protective covers shall be wood, wood fiber, plastic, or metal and securely attached to the valve ends by bolts, steel straps, or suitable friction locking devices. The covers shall be no smaller than the outside diameter of the valve ends and designed so that the valves cannot be installed without complete removal of the covers.
9.2.2 All threaded connections in the valve body shall be fitted with solid, fully tightened plugs conforming to ASME B16.11, or ASME B16.14. Gray iron or malleable iron plugs shall only be used on gray iron or ductile iron valves respectively.
9.2.3 Type B Check valves shall be shipped with the disc secured or supported during transport. A warning label shall be attached to the protective cover with instructions to remove, prior to installation, material from inside the valve that secures or supports the disc.
9.3 Packaging
9.3.1 When export packaging is not specified in the purchase order, valves may be shipped loose, palletized, or packed in a box or crate. Valves shall be packaged to prevent damage during shipment.
9.3.2 When the purchase order specifies export packaging, valves shall be shipped in wooden boxes or crates, individually or collectively, and packed to prevent their shifting within the package. (The shipping agent representing the purchaser will normally provide detailed instructions.)
10 Recommended Spare Parts
When specified on the purchase order, the vendor shall submit a complete list of spare parts. The list shall include cross-sectional or assembly-type drawings for identification with parts.


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