Overview
EN ISO 13971:2025 specifies requirements, classification, and installation best practices for flexible pipe elements, vibration isolators, expansion joints, and non-metallic tubes used in refrigerant circuits within refrigeration systems and heat pumps. Developed by CEN and based on ISO 13971:2012, this standard ensures the safe and efficient use of these components. It addresses both metallic (e.g., bellows, coiled tubes) and non-metallic (e.g., plastic, elastomer) elements, focusing on material selection, system design, tightness, and permeability to refrigerants and water vapor.
Key Topics
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Scope and Applicability
- Covers flexible pipe elements, vibration isolators, expansion joints, and non-metallic tubes in refrigeration and heat pump applications.
- Addresses both design and installation procedures.
- Does not include flexible pipes occasionally stressed beyond their elastic limit or free-hinged/rotating joints.
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Performance Requirements
- Specifies tightness and permeability criteria for non-metallic tubes.
- Sets out durability, fatigue, and internal cleanliness requirements for all pipe elements.
- Describes pressure resistance, including vacuum and burst test performance.
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Material Selection
- Materials must be resistant to the effects of specific refrigerants and remain flexible at low temperatures.
- Outlines compatibility testing under ISO 175 and ISO 6605 for both metallic and non-metallic elements.
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Installation and Safety
- Details proper installation to prevent over-stressing and ensure tight connections.
- Recommends that elements are installed according to manufacturer guidelines to avoid vibration and movement-related failures.
- Requires durable marking for identification (manufacturer, pressure, temperature, leak rate class).
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Environmental Protection
- Limits the permeation of refrigerants, reducing environmental impact (global warming, ozone depletion).
- Sets maximum allowable water vapor permeability for non-metallic tubes.
Applications
EN ISO 13971:2025 is critical for the design, manufacturing, and maintenance of refrigeration systems and heat pumps used in:
- Commercial refrigeration (supermarkets, cold stores, food processing)
- Industrial refrigeration systems
- Air conditioning and HVAC units
- Heat pumps in residential and commercial buildings
- Transport refrigeration (trucks, containers)
By standardizing requirements for flexible elements and expansion joints, this document helps:
- Prevent refrigerant leaks and reduce maintenance costs.
- Enhance the service life of refrigeration systems by minimizing failure points due to stress, vibration, or corrosion.
- Promote safe practices and compliance with environmental regulations.
Related Standards
EN ISO 13971:2025 should be used in conjunction with other key standards, including:
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ISO 5149 Series - Refrigeration systems and heat pumps - Safety and environmental requirements:
- ISO 5149-1: Definitions, classification, and selection criteria
- ISO 5149-2: Design, construction, testing, marking, and documentation
- ISO 5149-3: Installation site requirements
- ISO 5149-4: Operation, maintenance, repair, and recovery
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ISO 175 - Plastics - Methods of test for the determination of the effects of immersion in liquid chemicals
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ISO 6605 - Hydraulic fluid power - Hoses and hose assemblies - Test methods
By adhering to EN ISO 13971:2025 and these related standards, organizations ensure the reliability, efficiency, and environmental performance of their refrigeration and heat pump systems. This standard is essential for manufacturers, installers, and maintenance professionals working with refrigerant circuits.