Valve Standards Overview: ASME, API, ISO, and EN Comparison

Industrial valves are manufactured and tested to a large number of standards published by different standards bodies in different regions and for different industry sectors. Navigating this landscape of valve standards is essential for valve specifiers, purchasers, and inspectors who need to ensure that valves meet the technical requirements appropriate for each application. The major standards bodies whose valve standards are widely used globally include ASME (American Society of Mechanical Engineers), API (American Petroleum Institute), ISO (International Organization for Standardization), and EN (European Norm, published by CEN). Understanding which standards apply in which situations and how they relate to each other simplifies the specification process.

ASME Valve Standards

ASME publishes several foundational valve standards used globally. ASME B16.34 is the primary pressure-temperature rating standard for valves, defining the allowable working pressures at various temperatures for steel, stainless steel, and alloy valves in Classes 150 through 4500. ASME B16.10 specifies face-to-face and end-to-end dimensions for ferrous flanged and butt-welding end valves, ensuring dimensional interchangeability between different manufacturers. ASME B16.5 governs flange dimensions and pressure-temperature ratings. The ASME Boiler and Pressure Vessel Code (BPVC) Section I covers power boiler safety valves, and Section VIII Division 1 covers pressure relief valves on pressure vessels. ASME PTC 25 provides performance test code for pressure relief devices.

• ASME B16.34: pressure-temperature ratings for steel valves, Classes 150 to 4500

• ASME B16.10: face-to-face and end-to-end dimensions for flanged and butt-weld valves

• ASME B16.5: flanged fittings, pressure-temperature ratings for pipe flanges

• API 600: bolted bonnet steel gate valves for petroleum and natural gas industries

• API 6D: pipeline valves, ball, check, gate, and plug valves for pipelines

• ISO 17292: metal ball valves for petroleum, petrochemical, and natural gas industries

API Valve Standards

API publishes valve standards specifically for the petroleum, natural gas, and petrochemical industries. API 600 covers bolted-bonnet steel gate valves for refinery and general industry use, defining body design, materials, and testing requirements. API 602 covers compact steel gate valves. API 6D is the major pipeline valve standard, covering ball, gate, check, and plug valves for pipeline applications and defining requirements for pipeline-specific features such as full bore, double block and bleed, and pressure-testing procedures. API 607 defines fire test requirements for soft-seated quarter-turn valves to verify that they maintain acceptable leakage performance after exposure to fire conditions. API 6A governs wellhead and Christmas tree equipment.

ISO and EN Standards

ISO valve standards provide internationally harmonized requirements that are widely adopted outside North America and increasingly specified alongside or in place of ASME and API standards in global projects. ISO 17292 covers metal ball valves for petroleum and gas applications. ISO 10434 (equivalent to API 600) covers steel gate valves for the petroleum industry. ISO 15848 parts 1 and 2 address fugitive emissions testing and qualification, providing the international standard for low-emissions valve certification. EN 1176 series covers industrial valves for European markets, including gate, globe, check, ball, and butterfly valves with requirements harmonized with the EU Pressure Equipment Directive (PED). For projects with international procurement, specifying both the applicable ASME/API standard and the equivalent ISO/EN standard simplifies global sourcing.