API and ISO Standards for Large Bore Butterfly Valves Large bore butterfly valves are critical components in industrial applications, particularly in oil and gas, water treatment, and chemical processing. To ensure reliability, safety, and performance, these valves must comply with international standards set by organizations such as the American Petroleum Institute (API) and the International Organization for Standardization (ISO). Below is an overview of key API and ISO standards applicable to large bore butterfly valves. API Standards for Large Bore Butterfly Valves 1. API 609 – This standard specifies requirements for butterfly valves with a center-guided design, covering sizes from DN 50 (NPS 2) to DN 1200 (NPS 48) and pressure classes up to ASME 1500. It defines design, materials, testing, and inspection criteria to ensure durability in demanding applications. 2. API 6D – While primarily for pipeline valves, API 6D includes provisions for large bore butterfly valves used in high-pressure systems. It covers design, material selection, pressure testing, and fire-safe requirements. 3. API 598 – This standard outlines valve inspection and testing procedures, including pressure tests (shell, seat, and backseat) to verify leak-tightness. Large bore butterfly valves must undergo rigorous testing to meet API 598 requirements. 4. API 607/API 6FA – These standards define fire-safe testing for soft-seated butterfly valves, ensuring they can maintain integrity under extreme heat conditions. ISO Standards for Large Bore Butterfly Valves 1. ISO 10631 – This standard specifies general requirements for butterfly valves, including dimensions, materials, and pressure-temperature ratings. It applies to valves used in water, gas, and chemical services. 2. ISO 5752 – Defines face-to-face dimensions for flanged butterfly valves, ensuring interchangeability between manufacturers. 3. ISO 5211 – Standardizes mounting dimensions for valve actuators, facilitating compatibility with automated systems. 4. ISO 15848-1 – Addresses fugitive emissions testing, ensuring large bore butterfly valves meet stringent environmental regulations by minimizing leakage. Key Considerations for Compliance - Material Selection: Valves must use materials resistant to corrosion, erosion, and high temperatures, as specified in API and ISO standards. - Testing Requirements: Hydrostatic, pneumatic, and fire tests are mandatory to validate performance under operational conditions. - Dimensional Compliance: Large bore valves must adhere to standardized face-to-face and flange dimensions to ensure proper installation and interchangeability. Conclusion API and ISO standards provide a comprehensive framework for the design, manufacturing, and testing of large bore butterfly valves. Compliance with these standards ensures reliability, safety, and efficiency in critical industrial applications. Manufacturers and end-users must adhere to these guidelines to maintain operational integrity and regulatory compliance.