API 594-2004 pdf download.Check Valves: Flanged, Lug, Wafer and Butt-welding.
1 General 1.1 SCOPE This standard covers design, material, face-to-face dimen- sions, pressure-temperature ratings, and examination, inspec- tion, and test requirements for two types of check valves. 1.1.1 Type ‘A’ check valves are short face-to-face as defined in Tables 2A and 2B and can be: wafer, lug, or double flanged; single plate or dual plate; gray iron, ductile iron, steel, nickel alloy or other alloy designed for installation between Class 125 and 250 cast iron flanges as specified in ASME B16.1, between Class 150 and 300 ductile iron flanges as specified in ASME B16.42, between Class 150 – 2500 steel flanges as specified in ASME B16.5, and between Class 150 – 600 steel pipeline flanges as specified in MSS SP-44 or carbon steel flanges as specified in ASME B16.47. 1.1.2 Type ‘B’ check valves are long face-to-face as defined in 4.1.2 and can be: flanged or butt-welding; steel, nickel alloy or other alloy designed for installation between Class 150 – 2500 steel flanges as specified in ASME B16.5 or for butt-welding into industry accepted piping systems. 1.2 SIZES This standard covers the following nominal valve size ranges: Type ‘A’ valves: a. Classes 125 and 250, 2 ≤ NPS ≤ 48 (excluding NPS 3 1 / 2 ). b. Classes 150 and 300, 2 ≤ NPS ≤ 48* c. Class 600, 2 ≤ NPS ≤ 42* d. Classes 900 and 1500, 2 ≤ NPS ≤ 24* e. Class 2500, 2 ≤ NPS ≤ 12* Type ‘B’ valves: f. Classes 150 through 1500, 2 ≤ NPS ≤ 24* g. Class 2500, 2 ≤ NPS ≤ 12* Note: *Valve sizes NPS 3 1 / 2 and 5 are non-preferred sizes whose usage is discouraged. 1.3 VALVE NOMENCLATURE The standard nomenclature for valve parts is shown in Fig- ures 1, 2, 3, 4 and 5. Figures 1, 2, 3 and 4 illustrate typical Type ‘A’ check valves and Figure 5 illustrates a typical Type ‘B’ check valve. These figures show typical designs only and are not to be construed as precluding other available designs that comply with the requirements of this standard.
2 Normative References The following standards contain provisions which, through reference in this text, constitute provisions of this standard. At the time of publication of this standard, the editions of record are valid. All standards are subject to revision and parties to agreements based on this standard are encouraged to investi- gate the possibility of applying the most recent editions of the standards indicated below. API Std 598 Valve Inspection and Testing API 600 Bolted Bonnet Steel Gate Valves for Petro- leum and Natural Gas Industries ASME 1 B1.1 Unified Inch Screw Threads (UN and UNR Thread Form) B16.1 Cast Iron Pipe Flanges and Flanged Fittings B16.5 Pipe Flanges and Flanged Fittings B16.10 Face-to-Face and End-to-End Dimensions of Valves B16.11 Forged Steel Fittings, Socket-Welding and Threaded B16.14 Ferrous Pipe Plugs, Bushings, and Lock- nuts with Pipe Threads B16.20 Metallic Gaskets for Pipe Flanges—Ring Joint, Spiral Wound, and Jacketed B16.25 Butt-welding Ends B16.34 Valves—Flanged, Threaded and Welding End B16.42 Ductile Iron Pipe Flanges and Flanged Fittings, Classes 150 and 300 B16.47 Large Diameter Steel Flanges; NPS 26 Through NPS 60 B18.15 Forged Eyebolts
4 Design 4.1 BODY AND COVER 4.1.1 The minimum body wall thickness for various mate- rials shall be as follows: Type ‘A’ valves only: a. Gray iron: as shown in Tables 1A and 1B for Class 125 and Class 250 only. b. Ductile iron: as shown in Tables 1A and 1B for Class 150 and Class 300 only. Type ‘A’ and Type ‘B’ valves: c. Steel and chrome-moly steels per ASME B16.34, Table 1, Group 1: as shown in Tables 1A and 1B, for Classes 150, 300, 600, 900, 1500 and 2500 d. Nickel-base alloys per ASME B16.34, Table 1, Group 2 and other alloys per ASME B16.34, Table 1, Group 3: 1. For Classes 150, 300 and 600 only: as shown in ASME B16.34, Table 3. 2. For Classes 900, 1500 and 2500: as shown in Tables 1A and 1B. e. Special materials: The minimum body wall thickness for materials not covered by ASME B16.34 shall be as agreed between the purchaser and manufacturer. 4.1.2 The face-to-face dimensions shall be as follows: Type ‘A’ valves (including valves with ring-joint facings) shall con- form to those shown in Tables 2A and 2B. Type ‘B’ valves shall conform to ASME B16.10. Short pattern or special lengths are not permitted unless by agreement between pur- chaser and manufacturer. 4.1.3 The purchase order shall specify for Type ‘A’ valves whether the body type shall be wafer, lug or double flanged and for Type ‘B’ valves whether the body type shall be flanged or butt-welding. Type ‘A’ double-flanged valves will only be supplied where nut space between flanges is ade- quate. End and cover flanges of steel, nickel alloy and other alloy valves shall be integrally cast or forged with the body. However, flanges may be attached by full penetration butt- welding if agreed to by the purchaser. Flanges shall conform to ASME B16.5 and have butt-welding ends for use without backing rings.