API 594 Check valves: flanged, lug, wafer and butt-welding

Is API 594 still current?

Yes. API 594 10th ed., Sept 2026 (Errata 1, Oct 2026) is the latest edition MechAtlas found (MechAtlas review: 27 October 2026). Check the publisher for amendments before you specify it.

What it covers

Process check valves incl. dual-plate wafer types.

Parts that use API 594

• Check valve (USA (ASME / ASTM), main)
  Valve that lets flow pass one way and closes automatically to stop back-flow.
  Grades: Class 150 to 2500
  Flanged, lug, wafer and butt-weld check valves (10th ed. 2026).

Official source

MechAtlas does not reproduce standards. Check the official edition at the publisher's page for API 594 or the API store.

Other valves standards

• API 598 / ISO 5208 / EN 12266-1 Changing
  Valve inspection and pressure testing
• API 526 / 527 / 520 / ISO 4126 Current
  Relief valve dimensions, seat tightness, sizing
• API 598 Current
  Valve inspection & testing
• API 600 Current
  Steel gate valves
• API 602 / 608 / 609 Current
  Compact gate, ball, butterfly valves
• API 6D Current
  Specification for valves (absorbed RP 6DR)
• ASME B16.10 / EN 558 Current
  Face-to-face dimensions
• ASME B16.34 Current
  Valves — flanged, threaded & welding end
• AWWA C504 Current
  Rubber-seated butterfly valves (water)
• BS 1868 Current
  Steel check valves, flanged and butt-welding, petroleum industry
• EN 1171 Current
  Cast iron gate valves
• EN 16767 Current
  Metallic check valves

All Valves standards →