Understanding ISO 24664:2024 Compliance Requirements
SN EN ISO 24664:2025
Kälteanlagen und Wärmepumpen - Druckentlastungseinrichtungen und zugehörige Leitungen - Berechnungsverfahren (ISO 24664:2024)
Refrigerating systems and heat pumps - Pressure relief devices and their associated piping - Methods for calculation (ISO 24664:2024)
This document describes the calculation of: — mass flow for sizing pressure relief devices for parts of refrigerating systems; — discharge capacities for pressure relief valves and other pressure relief devices in refrigerating systems including the necessary data for sizing these when relieving to atmosphere or to part of the refrigerating system at lower pressure; — the pressure loss in the inlet and outlet lines of pressure relief valves and other pressure relief devices and includes the necessary data. This document specifies the requirements for selection of pressure relief devices to prevent excessive pressure due to internal and external heat sources, the sources of increasing pressure (e.g. compressor, heaters, etc.) and thermal expansion of trapped liquid. NOTE The term "refrigerating system" used in this document includes heat pumps.
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Purpose and objectives
The primary aim of SN EN ISO 24664:2025 is to provide standardized methodologies for calculating the mass flow rates and discharge capacities of pressure relief devices. This standard ensures that pressure relief systems are designed to function effectively and safely under various operational conditions. By adhering to these guidelines, manufacturers and operators can minimize risks associated with pressure buildup in refrigerating systems and heat pumps, thereby enhancing safety and compliance with international regulations. Ultimately, the standard promotes engineering practices that contribute to the reliability and efficiency of pressure relief devices in diverse applications.
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Scope: who must comply
SN EN ISO 24664:2025 applies to a broad range of stakeholders involved in the design, manufacturing, and operation of refrigerating systems and heat pumps. This includes:
- Manufacturers of pressure relief devices such as discharge valves and burst discs.
- Engineers and designers responsible for system design and safety assessments.
- Facility managers in industries such as food processing, pharmaceuticals, and HVAC.
- Regulatory bodies ensuring compliance with safety standards in the Energy & Heat Transfer context. By following the compliance requirements outlined in this standard, organizations can ensure that they meet both safety and regulatory expectations.
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How SN EN ISO 24664:2025 relates to other standards
SN EN ISO 24664:2025 is interconnected with several other standards that enhance its framework:
- ISO 9001: A quality management standard that ensures organizations consistently meet customer and regulatory requirements.
- SN EN 13136+A1:2019: This standard focuses on the performance and testing of pressure relief devices, providing complementary guidelines.
- Pressure Equipment Directive 2014/68/EU: A regulatory framework that mandates safety standards for pressure equipment, including those covered by ISO 24664:2025.
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Revision history and current status
The standard was last revised in 2025, reflecting ongoing developments in technology and safety practices. Significant changes in this revision included updated calculation methods for mass flow rates and enhanced guidelines for pressure drop calculations in inlet and outlet piping. These updates are designed to align better with current industry practices and regulatory requirements, ensuring that users have access to the most relevant and effective guidelines for pressure relief devices.