Overview
SIST EN ISO 21922:2022 (identical to ISO 21922:2021) specifies safety, functional, testing and marking requirements for valves used in refrigerating systems and heat pumps. The standard covers valves (including those with extension pipes) intended for systems with a maximum operating temperature up to 200 °C and a maximum allowable pressure up to 160 bar (1 bar = 0.1 MPa). It also addresses design procedures and material selection for pressure-bearing parts and provides methods to account for reduced impact properties at low temperatures. The document applies to bodies and bonnets of pressure relief devices (including bursting discs) only with respect to pressure containment.
Keywords: SIST EN ISO 21922:2022, ISO 21922:2021, refrigerating systems, heat pumps, valves, testing, marking, pressure containment.
Key Topics and Requirements
- Scope and applicability: Valves for refrigerating systems and heat pumps, including valves with extension pipes; limits of 200 °C and 160 bar.
- Materials: Selection criteria for metallic and non-metallic materials for pressure-bearing parts, ductility, ageing, castings, forgings, nuts/bolts, spindles and glass components.
- Design: Procedures for designing bodies, bonnets, joints and assemblies to withstand pressure; rules for allowable stresses and strength calculations or experimental verification.
- Low-temperature behavior: Methods for safely taking reduced impact energy values into account when operating at low temperatures.
- Pressure relief components: Design requirements for bodies and bonnets of pressure relief devices limited to pressure containment.
- Manufacturing and production testing: Requirements for strength pressure testing, tightness testing, seat sealing capacity tests, and caps.
- Function and operability: Requirements for hand-operated and actuator-operated valve operation and tightness.
- Marking and documentation: Mandatory marking, labelling, operating instructions and manufacturer documentation; guidance on marking allowable pressure/temperature limits.
- Regulatory alignment: Annex ZA links the standard to essential safety requirements of EU Directive 2014/68/EU for pressure equipment.
Practical Applications and Users
This standard is essential for:
- Valve manufacturers and designers producing components for refrigeration and heat pump systems.
- OEMs and system integrators specifying valve performance, materials and testing.
- Testing laboratories performing type and production tests (pressure, tightness, seat tests).
- Regulatory and compliance teams ensuring conformity with pressure equipment directives and national adoption (CEN endorsement).
- Maintenance and safety engineers assessing valves for low-temperature operation, pressure relief containment and correct marking.
Practical benefits include improved safety, consistent testing/marking, clearer material selection rules and traceable documentation for valves in refrigeration and heat pump applications.
Related Standards
- ISO 21922:2021 (international text) - adopted as SIST EN ISO 21922:2022.
- Supersedes EN 12284:2003.
- Links to Directive 2014/68/EU (pressure equipment).