API 600 Steel Gate Valve Standards

API 600 is the primary standard for bolted bonnet steel gate valves used in petroleum and natural gas industries. It establishes design, material, inspection, and testing requirements for valves from NPS 2 through NPS 24 in pressure classes 150 through 2500.

Scope and Application

• Flanged and butt-welding end connections in all standard pressure classes

• Full port and reduced port bore configurations

• Flexible and solid wedge, and slab gate designs

• Outside screw and yoke (OS&Y) stem design standard

• Rising stem and non-rising stem configurations covered

Material Requirements

API 600 references ASTM material specifications for all pressure-containing parts. Body and bonnet materials must conform to ASTM A216 (carbon steel), A217 (alloy steel), or A351 (stainless steel) casting specifications, or equivalent forging standards. Trim materials are classified by ASTM grade, with API Trim 8 (13Cr seats and stem) the most common selection for general hydrocarbon service.

Design Requirements

• Wall thickness per ASME B16.34 pressure-temperature ratings

• Backseat design to allow packing replacement under pressure

• Gland follower and packing arrangement requirements

• Stem thread form and geometry requirements

• Hand wheel to stem torque calculations and stem sizing

Testing Requirements

Every API 600 valve must undergo shell hydrostatic test at 1.5 times the 38°C (100°F) pressure rating and seat leakage test. The seat leakage test uses water at the valve's maximum allowable working pressure (MAWP), with acceptance criteria depending on the leakage class specified. API 598 governs the detailed test procedures for API 600 valves.

Related Standards

• API 598: Valve inspection and testing

• ASME B16.34: Valves - flanged, threaded and welding end

• ASME B16.10: Face-to-face and end-to-end dimensions

• ASME B16.5: Pipe flanges and flanged fittings

• NACE MR0175/ISO 15156: Materials for sour service