# API 607 vs API 608: A Comprehensive Comparison for Valve Selection
Choosing the right fire-safe valve is critical for safety and compliance in demanding industries. Two key standards often cause confusion: **API 607 and API 608**. This guide provides a detailed comparison to inform your valve selection process.
## **Core Purpose and Application Scope**
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Understanding Fire Test Standards for Valves
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Both API 607 and API 608 define fire-test requirements for quarter-turn valves, but their scope differs significantly. API 607 is a testing standard applicable to a wide range of quarter-turn valves, including ball, butterfly, and plug valves, regardless of their design or material. Its primary focus is on evaluating the valve’s ability to contain internal and external leakage during and after a fire simulation.
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API 608: The Metal Ball Valve Standard
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Conversely, API 608 is a comprehensive product specification for metal ball valves. It covers design, materials, dimensions, testing, and inspection. The fire-test within API 608 is just one part of this larger specification. Essentially, API 608 valves are built to a specific design standard and must also pass a fire test based on API 607’s methodology.
## **Key Differences in Testing and Performance**
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Fire Test Duration and Acceptance Criteria
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A major difference lies in the fire test duration. The latest edition of API 607 (7th Edition) mandates a rigorous 30-minute fire test. API 608 references an older, less stringent 15-minute fire test from a previous API 607 edition. The longer test in modern API 607 represents a more severe and realistic performance benchmark for extreme fire scenarios.
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Seat Material and Design Implications
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This difference often relates to seat materials. Valves certified to the full API 607 standard frequently use advanced polymeric or elastomeric seats designed to char in a controlled way to maintain a seal. API 608 metal-seated ball valves rely on metal-to-metal sealing, which is inherently more fire-resistant but may have different performance characteristics in normal operation.
## **Making the Right Choice for Your System**
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Selection Criteria: Safety, Fluid, and Cost
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Your choice depends on operational risk, the process fluid, and budget. For the highest level of assured fire safety, especially with flammable fluids, a valve certified to the latest API 607 standard is often specified. For general hydrocarbon service where a robust metal ball valve is required, an API 608 compliant valve is a common and reliable choice.
For a deeper technical breakdown of design and testing nuances, you can explore this detailed resource on api 607 vs api 608.
## **Frequently Asked Questions (FAQ)**
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Can an API 608 valve also be API 607 certified?
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Yes. A metal ball valve manufactured to API 608 can be independently fire-tested and certified to the API 607 standard, offering dual compliance.
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Which standard is more stringent?
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The fire test in the latest API 607 edition (30 minutes) is more severe than the test referenced in API 608 (15 minutes).
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