Overview
EN ISO 21922:2021/A1:2024 - "Refrigerating systems and heat pumps - Valves - Requirements, testing and marking - Amendment 1" (CEN) is an amendment to the ISO 21922:2021 standard. It specifies safety and selected functional requirements, testing procedures and marking for valves (including valves with extension pipes) used in refrigerating systems and heat pumps. The amendment clarifies seat tightness classes, leakage measurement definitions and calculation formulae, and reinforces requirements for design, material selection and low-temperature performance. It applies to valves with a maximum operating temperature ≤ 200 °C and a maximum allowable pressure ≤ 160 bar.
Key topics and requirements
- Scope and applicability
- Valves and valve-like components for refrigerating systems and heat pumps, including extension pipes.
- Design of bodies and bonnets for pressure relief devices only with respect to pressure containment.
- Safety and functional requirements
- Procedures for designing parts subjected to pressure and criteria for material selection.
- Methods to account safely for reduced impact values at low temperatures.
- Seat tightness and leakage testing (clarified in Amendment 1)
- Seat tightness classes A–H with maximum leakage percentage limits and test methods.
- Specific requirement: valves permanently venting to atmosphere require seat tightness class A.
- Leakage measurement definitions added/updated: mass flow (Q in kg/h), upstream/downstream volumetric flow (V1, V2), and flow coefficient K (m3/h).
- Formulas (1)–(3) for calculating leakage percentage L from measured leakage, K, test differential pressure and densities.
- Type testing with gas (air or nitrogen) covering the full differential pressure range.
- Marking and documentation
- Requirements for marking, technical documentation and operating instructions aligned with pressure-equipment directives where applicable.
Applications and users
- Intended for:
- Valve manufacturers designing and testing valves for refrigeration and heat pumps.
- OEMs and system designers specifying valve performance and sealing requirements.
- Test laboratories performing seat tightness and pressure containment tests.
- Compliance engineers, notified bodies and inspection authorities verifying conformity with safety requirements and EU Directive 2014/68/EU (presumption of conformity under specified referenced editions).
- Practical uses:
- Selecting valve types and materials for low-temperature refrigerants.
- Defining test protocols and acceptance criteria for seat leakage and pressure containment.
- Ensuring correct marking and documentation for regulatory compliance.
Related standards
Normative and informative cross-references included in the amendment:
- ISO 148-1 (Charpy impact test)
- ISO 5149 (refrigerating systems safety)
- ISO/TR 15608 (welding material grouping)
- EN 12516-2 (industrial valve shell design calculation)
- EN 13445-3 (unfired pressure vessel design)
- EN 14276-2 (pressure equipment for refrigerating systems and heat pumps)
This amendment improves clarity on leakage measurement and seat tightness classification, making EN ISO 21922:2021/A1:2024 essential for professionals involved in valve design, testing and compliance within refrigeration and heat pump applications.