1. Core design standards
API 602
Positioning: Special standard for forged steel stop valves, suitable for small-diameter (DN≤100mm) high-pressure scenarios, suitable for oil and natural gas pipeline systems.
Technical points:
Clear valve connection methods (threaded, socket welded, flanged) and structural compactness requirements;
The valve stem adopts an anti-blowout design (Anti-blowout stem) to ensure safe operation under high-pressure conditions.
API 598
Function: General specification for the sealing and strength testing of stop valves, used in conjunction with API 602.
Test requirements:
Shell strength test: 1.5 times the nominal pressure (Class 150 valves must withstand ≥3.1MPa), maintain pressure for 3 minutes without leakage;
Sealing test: Gas medium leakage rate ≤ISO 5208 Class VI (about 10^-6 mL/s).
2. Supporting standards
API 6D
Scope of application: Supplementary specifications for stop valves for oil and gas pipeline systems, including full bore and non-full bore structural design criteria.
Material requirements: High-strength materials such as ASTM A105 forged steel and A182 F304 stainless steel are commonly used for valve bodies, and MTR material certification reports are required.
API 6FA
Special scenarios: In response to fire protection requirements, the pressure bearing capacity verification method and fire resistance performance indicators of stop valves under fire conditions are specified.
3. Comprehensive application specifications
Structural length and connection
Flange end: Follow API 605/ASME B16.5 to define the flange size and sealing surface accuracy requirements for Class 150~2500; Welding end: Bevel processing is performed according to ASME B16.25 specifications, and is suitable for high-pressure pipeline welding processes.
Material and Seal
Valve Disc/Valve Seat: Overlaying Stellite or cemented carbide, hardness ≥ HRC40, to ensure erosion resistance; Stuffing Box: Multi-layer graphite or PTFE packing combination, meeting ASTM F104 leakage level requirements.
