Overview - What ISO 21922:2021 covers
ISO 21922:2021, "Refrigerating systems and heat pumps - Valves - Requirements, testing and marking", defines safety, functional and marking requirements for valves used in refrigerating systems and heat pumps. The standard covers valves (including those with extension pipes), design procedures for pressure-bearing parts, material selection criteria, and methods to safely account for reduced impact values at low temperatures. It also addresses pressure containment for bodies and bonnets of pressure relief devices (e.g., bursting discs). ISO 21922:2021 applies to valves with a maximum operating temperature ≤ 200 °C and maximum allowable pressure ≤ 160 bar.
Key technical topics and requirements
- Safety and functional requirements for valves used in refrigeration and heat pump systems.
- Design procedures for pressure-bearing parts (normative annexes include calculation and experimental design methods).
- Material selection and compatibility rules, including guidance on metallic and non-metallic materials, castings, forgings, and ageing.
- Low-temperature considerations: procedures to account for reduced impact energy and avoid brittle fracture.
- Pressure containment requirements for bodies and bonnets of pressure relief devices (limited to pressure containment aspects).
- Testing and production checks: strength pressure testing, tightness testing, seat sealing capacity, and other production tests.
- Marking and documentation: mandatory marking elements, allowable pressure/temperature markings, and required documentation for valves and valve assemblies.
- Annexed methods and verification: includes Annexes A–M covering calculation methods, experimental design, allowable pressure at temperature extremes, material characteristics, pressure strength verification, DN sizing, sight glass requirements, compatibility screening, and stress corrosion guidance.
Practical applications and who uses this standard
ISO 21922:2021 is used by:
- Valve manufacturers and designers to ensure safe mechanical design, material selection and conformity with refrigeration/heat pump requirements.
- Test laboratories and quality control teams to carry out strength, tightness and seat sealing tests per the standard.
- System integrators and OEMs specifying valves for refrigeration, air conditioning and heat pump systems.
- Certification bodies and regulators assessing compliance for safety and marking.
- Maintenance and safety engineers seeking guidance on operating limits, documentation and inspection criteria.
Benefits include improved safety, reliable pressure containment, clearer traceability through marking, and reduced risk of brittle failure in low-temperature applications.
Related standards and references
- ISO 148-1 (Charpy impact test for metallic materials) - cited for low-temperature impact assessment.
- ISO 5149-1 (Refrigerating systems and heat pumps - Safety and environmental requirements) - normative context.
- ISO 21922:2021 is based on EN 12284:2003; consult national standards bodies for adoption and implementation details.
Keywords: ISO 21922:2021, refrigerating systems, heat pumps, valves, valve testing, valve marking, pressure containment, material selection, low temperature brittle fracture.
