ISO 21011:2008

Overview - ISO 21011:2008 (Cryogenic valves)

ISO 21011:2008 specifies requirements for the design, manufacture and testing of valves for cryogenic service - valves rated for temperatures of −40 °C and below. It applies to all types of cryogenic valves, including vacuum‑jacketed cryogenic valves up to DN 150, for use with cryogenic fluids and for operation from ambient down to cryogenic temperatures. This standard excludes pressure relief valves covered by ISO 21013‑1.

Key topics and technical requirements

• Scope and definitions: Nominal size (DN), rated pressure, rated minimum temperature, valve categories (Category A = 2 000 cycle operation simulation; Category B = 100 cycles), flow coefficients (Kv and Cv) and other terms.
• Materials: Metallic and non‑metallic material selection requirements, including conformity with ISO 21028‑1 / ISO 21028‑2 for toughness at cryogenic temperatures; requirements for oxygen compatibility (see ISO 21010), hydrogen compatibility (ISO 11114‑1/2) and specific guidance (e.g., copper content <70% for acetylene service).
• Design: Safe operation from +65 °C down to the rated minimum temperature; minimum wall/bonnet thickness referenced to valve standards; extended stems/bonnets for packing temperature control; prevention of trapped‑liquid cavities and debris, seat and stem securement, limits on manual operating torque (maximums expressed as multiples of handwheel/lever radius).
• Testing: Type approval tests (operation simulation, leak tightness), production tests, and test reporting requirements. Annex A provides recommended methods for leak‑tightness testing of cryogenic valves.
• Cleanliness and marking: Cleanliness requirements for cryogenic service (referencing ISO 23208), and mandatory marking on valve body and identification plate.

Applications and who uses ISO 21011:2008

• Manufacturers and designers of cryogenic valves and cryogenic vessel components to ensure materials, design and testing meet international safety and performance expectations.
• Procurement and quality assurance teams specifying valves for LNG, industrial gas (oxygen, nitrogen, hydrogen), research cryogenic equipment, and vacuum‑jacketed piping systems.
• Inspection, testing and certification bodies conducting type approval, production testing and issuing test reports.
• Operators and plant engineers who need assurance that valves will perform safely across ambient-to-cryogenic temperature ranges and in specific gas services (oxygen/oxidizers, hydrogen, acetylene).

Related standards (normative references)

• ISO 21013‑1 (pressure relief valves) - excluded from this standard
• ISO 21010 (cryogenic gas/materials compatibility)
• ISO 21028‑1 / ISO 21028‑2 (toughness at cryogenic temperatures)
• ISO 23208 (cleanliness for cryogenic service)
• ISO 5208, ISO 10434, ISO 15761, ISO 17292, ISO 11114‑1/2
• ASME B16.34 (valve design/end connections)

Keywords: ISO 21011:2008, cryogenic valves, valves for cryogenic service, cryogenic vessels, cryogenic valve testing, DN 150, design and materials, cryogenic valve standards.