What is the difference between API 598 and 607

1. Standard positioning and target differences
‌API 598‌:
It is a general inspection and pressure test standard for valves, applicable to all types of industrial valves (such as gate valves, ball valves, stop valves, etc.). The core goal is to verify whether the sealing performance and structural strength of the valve meet the design requirements.
‌API 607‌:
Specially formulated for the fire performance test of 1/4-turn valves (such as ball valves and butterfly valves), focusing on verifying the emergency sealing ability and structural integrity of the valve under fire environment.
2. Test content and verification indicators
‌API 598 test requirements‌:
‌Shell strength test‌: Test the leakage-free ability of pressure-bearing parts such as valve body and valve cover at 1.5 times the rated pressure;
‌Sealing performance test‌: Leakage detection of valve seat seal (low-pressure gas + high-pressure liquid) and valve stem packing, respectively, with the maximum allowable leakage rate ≤100ppm;
‌Operation torque test‌: Verify whether the mechanical performance of the valve opening and closing process is stable.
‌API 607 ​​test requirements‌:
‌High temperature fire resistance test‌: Place the valve in a 650℃~1,000℃ flame for 30 minutes to simulate the continuous sealing performance under fire environment;
‌Emergency seal verification‌: After the soft seal fails, the metal sealing structure must be used to maintain the leakage within a controllable range (such as gas leakage rate ≤40cm³/min);
‌Anti-static and fire-proof redundant design‌: The valve is required to have a built-in spring anti-static device and fire-proof graphite packing.
3. Applicable objects and industry scenarios
‌API 598 scope of application‌:
Applicable to factory inspection and acceptance testing of all industrial valves, which is the basic basis for valve manufacturers and users to verify product compliance.
‌API 607 ​​scope of application‌:
Mainly for flammable and explosive media scenarios in the fields of petroleum, natural gas and chemicals, it is mandatory for valves to maintain basic cutoff functions after a fire.
4. Differences in certification processes
‌API 598‌:
The manufacturer usually performs the test and records the data according to the standard, and the user can request a third-party agency to review it.
‌API 607‌:
Must pass the flame simulation test certification of a third-party laboratory and cover valve models of different sizes and pressure levels.