# API 607 vs API 608: Key Differences Explained

API 607 vs API 608: Key Differences Explained

When it comes to valve testing standards in the oil and gas industry, API 607 and API 608 are two critical specifications that often get compared. While both standards relate to fire testing of valves, they serve different purposes and apply to different valve types. Understanding the differences between these standards is essential for engineers, procurement specialists, and safety professionals working with industrial valves.

What is API 607?

API 607 is the standard for fire testing of quarter-turn valves and valves equipped with non-metallic seats. Originally developed in 1985, this standard specifies the fire test requirements for soft-seated valves that need to demonstrate their ability to maintain sealing integrity during and after exposure to fire conditions.

The current edition, API 607 7th Edition, applies to various valve types including ball valves, butterfly valves, plug valves, and other quarter-turn designs. The standard requires valves to undergo rigorous testing where they’re exposed to temperatures up to 1,400-1,800°F (760-980°C) for 30 minutes while under pressure.

What is API 608?

API 608 covers metal-seated ball valves for flanged, threaded, and welding end connections. While it includes some fire testing requirements, API 608 is primarily a comprehensive standard that specifies design, materials, dimensions, testing, and inspection requirements for metal-seated ball valves.

The fire test portion of API 608 is similar to API 607 but specifically applies to metal-seated ball valves. The standard ensures these valves can maintain structural integrity and some degree of sealing capability during fire exposure.

Key Differences Between API 607 and API 608

1. Valve Types Covered

API 607 applies to quarter-turn valves with non-metallic seats, while API 608 specifically addresses metal-seated ball valves.

2. Scope of Standards

API 607 is exclusively a fire testing standard, whereas API 608 is a comprehensive standard covering design, manufacturing, and testing of metal ball valves including fire testing.

3. Seat Materials

The most significant difference lies in the seat materials: API 607 focuses on soft-seated (non-metallic) valves, while API 608 deals with metal-to-metal seated valves.

4. Testing Duration

API 607 requires a 30-minute fire test, while API 608’s fire test duration may vary based on valve size and application requirements.

5. Leakage Criteria

API 607 has more stringent leakage requirements after fire testing compared to API 608, reflecting the different performance expectations for soft-seated versus metal-seated valves.

When to Use Each Standard

Choose API 607 when you need to verify the fire safety of quarter-turn valves with soft seats, particularly in applications where zero leakage after fire exposure is critical.

Select API 608 when specifying metal-seated ball valves for general service, especially in applications where the valve may be exposed to fire but complete sealing after fire exposure isn’t the primary concern.

Conclusion

While both API 607 and API 608 address fire testing of valves, they serve distinct purposes in the industry. API 607 is the go-to standard for fire testing soft-seated quarter-turn valves, while API 608 provides comprehensive