**ASME B16.34 vs. API 600: Understanding the Core Differences**
In the world of industrial valves for demanding services, two standards are paramount: ASME B16.34 and API 600. While often mentioned together, they serve distinct but complementary purposes. This guide cuts through the complexity to provide a clear comparison for engineers, specifiers, and procurement professionals.
Keyword: two commonly asme b16 34 and api 600
**Scope and Primary Focus**
ASME B16.34, titled “Valves – Flanged, Threaded, and Welding End,” is a foundational pressure-temperature rating standard. It defines the wall thickness, materials, and design requirements for valve bodies, bonnets, and covers to ensure pressure integrity. It applies to a broad range of valve types (gate, globe, check, etc.) made from various materials.
In contrast, API 600, “Steel Gate Valves – Flanged and Butt-Welding Ends, Bolted Bonnets,” is a product specification standard. It details the specific design, material, testing, and inspection requirements for bolted bonnet steel gate valves primarily used in refinery and pipeline services. API 600 valves must first meet the pressure-retaining requirements of ASME B16.34.
**Key Design and Material Requirements**
A major difference lies in construction. API 600 mandates a pressure seal bonnet or a bolted bonnet with a flexible, self-energizing gasket for certain pressure classes, enhancing sealing under high pressure. ASME B16.34 does not specify bonnet design.
For trim (sealing surfaces), API 600 has stricter minimum hardness requirements and often specifies Stellite or equivalent hardfacing for severe service, which is not a blanket requirement in B16.34. Furthermore, API 600 requires a minimum body wall thickness that is often greater than the minimum calculated by B16.34, adding a safety margin.
**Choosing the Right Standard for Your Application**
Selecting between these standards hinges on service conditions. For general industrial applications requiring pressure integrity, ASME B16.34 compliance is essential. For severe, critical services in the oil & gas, petrochemical, and refining industries—especially for gate valves handling hydrocarbons, high pressures, and erosive/corrosive flows—specifying an API 600 valve ensures a more robust, durable, and field-proven product.
Think of it this way: ASME B16.34 defines the minimum safety requirements for pressure containment. API 600 builds upon that foundation with additional requirements to ensure long-term reliability and performance in harsh environments.
**Common Questions Answered**
Can a valve meet both standards? Yes. An API 600 valve inherently meets the relevant requirements of ASME B16.34 for its pressure class. It is the more stringent specification.
Which standard is more expensive? API 600 valves typically cost more due to additional material, manufacturing, and testing requirements (like more rigorous NDE).
Is API 600 only for gate valves? Primarily, yes. API 602 covers compact steel gate valves, and API 608 covers ball valves. ASME B16.34 covers multiple valve types.
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