Overview
ISO 14903:2025 - Refrigerating systems and heat pumps - Qualification of tightness of components and joints establishes a type-approval procedure to verify the leak tightness of hermetically sealed and closed components, joints and parts used in refrigerating systems and heat pumps. The standard covers assemblies (as supplied and assembled according to the manufacturer) including metal flexible piping, with applicability limits of joints up to DN 50, internal volumes up to 5 L, and weights up to 50 kg. Components tested and found compliant with ISO 14903:2017 remain compliant with this edition.
Key technical topics and requirements
- Scope and applicability: Hermetically sealed and closed components (fittings, bursting discs, flanged assemblies, valves, service ports) regardless of material or seal design. Excludes non‑metallic flexible piping (see ISO 13971).
- Type‑approval and tightness levels: Defines the required level of tightness for whole components and assemblies, and the information suppliers must provide for testing and qualification.
- Test programme:
- Sampling and test temperature requirements
- Quantitative tightness testing and tightness level control
- Pressure–temperature–vibration (PTV) testing - updated in 2025 edition (removal of the integrated vibration method; retained/updated the combined pressure–temperature cycle with a separate vibration test)
- Torque control for joints, testing of reusable and permanent joints, and special requirements for hermetically sealed joints
- Operation simulation, freezing tests, vacuum tests and fatigue tests for sealed joints
- Compatibility screening of sealing materials and refrigerants
- Test reporting and user information: Required content of test reports and the minimal information manufacturers must provide to test laboratories and system installers.
- Normative references: Connects to related standards such as ISO 5149 (system safety and environmental requirements) and ISO 20485 (tracer gas leak testing).
Practical applications
- Qualification of fittings, welded/brazed assemblies, service valves and other components for refrigerant containment in refrigeration and heat pump systems.
- Verifying component performance under combined thermal, pressure and vibration stresses representative of real operation.
- Supporting product development, quality assurance, supplier audits and regulatory compliance for refrigerant leak control.
- Supplying tested components for systems that must meet the safety and environmental requirements of the ISO 5149 series.
Who should use this standard
- Manufacturers of refrigeration and heat‑pump components and metal flexible piping
- Independent test laboratories and certification bodies performing type approval and leak testing
- HVACR design engineers, procurement and quality managers focused on refrigerant containment and safety
- Regulatory and compliance professionals referencing international tightness qualification criteria
Related standards
- ISO 5149 (refrigerating systems and heat pumps - safety & environmental requirements)
- ISO 13971 (tightness of flexible piping made from non‑metallic material)
- ISO 20485 (tracer gas leak testing)
- ISO 175 / ISO 1817 (material compatibility testing references)
Keywords: ISO 14903:2025, refrigerating systems, heat pumps, tightness qualification, hermetically sealed, leak test, PTV, refrigerant containment, ISO 5149.