Trunnion ball valves (fixed ball valves) must meet a number of international and industry standards to ensure their reliability and safety under high pressure and harsh working conditions. The core standard system is as follows:
1. Main body design standards International general specifications API 6D: Standardizes the design, materials and testing requirements of ball valves for oil and gas pipelines, and clarifies the difference in the pressure application range between trunnion structures and floating balls.
ASME B16.34: Specifies valve pressure-temperature ratings, wall thickness calculations and connection flange dimensions, covering Class 150 to 2500.
Domestic standards GB/T 12237: Equivalent to API 6D, specifies the manufacturing and inspection requirements of fixed ball valves (such as minimum wall thickness of the valve body and sealing structure).
JB/T 79: Standardizes flange connection dimensions to ensure the compatibility of valves and pipelines.
2. Key performance test standards
Sealing test
API 598/GB/T 13927: requires high-pressure gas sealing test (usually ≥1.1 times the working pressure) and liquid sealing test, leakage rate ≤ISO 5208 A grade (zero visible leakage).
Fire safety certification
API 607/ISO 10497: mandatory requirement that the metal seal can still maintain sealing for 30 minutes after the soft sealing seat is burned (simulating fire environment).
Extreme working condition verification
Ultra-low temperature test: liquid nitrogen environment (-196℃) to verify material toughness and sealing performance;
High temperature test: the highest verification temperature reaches 850℃ (such as metallurgical flue gas valves).
3. Special certification and structural requirements
Explosion-proof and safety certification
ATEX/IECEx: certification of pneumatic actuators suitable for flammable and explosive environments.
Valve seat configuration standard
DBB (double blocking and bleed): valve cavity pressure can be released after closing to verify the integrity of upstream and downstream seals;
DIB (double isolation and bleed): single valve seat bidirectional seal to meet the isolation requirements of high-risk scenarios such as nuclear power plants.
Anti-flyout structure
The valve stem needs to be integrated with an anti-slip design (such as a stepped shaft structure) to prevent the valve stem from being detached due to the impact of high-pressure media.
4. Materials and manufacturing standards
Material of pressure-bearing parts
Valve body/ball: ASTM A216 WCB (carbon steel), A351 CF8M (stainless steel) or customized alloy (such as zirconium);
Valve seat seal: metal hard seal (Stellite alloy) or composite PTFE (≤232℃).
Non-destructive testing
Pressure-bearing welds need 100% radiographic testing (RT) or ultrasonic testing (UT) to meet ASME BPVC Section V requirements.
