ISO 817:2024

Overview

ISO 817:2024 - "Refrigerants - Designation and safety classification" is the fourth edition of the International Standard that defines an unambiguous system for naming refrigerants and assigning safety classifications. The standard establishes rules for refrigerant designation, a matrix-based safety group classification (based on toxicity and flammability), and a method for determining refrigerant concentration limits. It also includes tables and annexes with classification data, property data and calculation methods submitted with refrigerant applications. ISO 817:2024 replaces ISO 817:2014 and expands the scope to include data necessary for safe application and updated toxicity classification rules.

Key Topics

• Refrigerant numbering and designation rules: detailed conventions for identifying refrigerants, including digits, prefixes, isomer and cyclic/ether-based compound rules, and blend identification.
• Safety classification system: assignment of toxicity and flammability classes and a matrix diagram for safety group determination.
• Refrigerant concentration limits (RCLs): methods to determine safe concentration limits, incorporating concepts such as Acute-toxicity Exposure Limit (ATEL) and Oxygen Deprivation Limit (ODL).
• Blends and azeotropes/zeotropes: rules for blend designation, tolerances and composition uniqueness.
• Data and testing requirements: reference to testing and data sources (flammability test methods, hot surface ignition, fractionation analysis) and annexes detailing test procedures and calculation methods.
• Special compound classes: treatment of ether-based, inorganic and miscellaneous organic refrigerants, isomer identification and stereoisomer rules.
• Annexes and tables: normative annexes with classifications and properties, calculation examples (e.g., ATEL for blends) and informative guidance (e.g., isomer designation examples).

Applications / Who Uses It

ISO 817:2024 is essential for:

• Refrigeration and air-conditioning manufacturers specifying refrigerants and labeling equipment.
• Product designers and safety engineers performing risk assessments and charge-limit calculations.
• Standards bodies, regulators and certification agencies harmonizing refrigerant naming and safety requirements.
• Test laboratories preparing and submitting data for refrigerant classification and for flammability/toxicity testing.
• HVAC service providers and building safety managers ensuring compliant refrigerant use and safe installation practices.

Related Standards

ISO 817 references and aligns with established test methods and standards such as ANSI/ASHRAE Standard 34 and ASTM test methods (e.g., flammability and ignition tests). Application and submission requirements for designation and classification have been centralized at the ISO maintenance page (see ISO 817 online resource).

Keywords: ISO 817:2024, refrigerants designation and safety classification, refrigerant concentration limits, ATEL, ODL, toxicity and flammability, refrigerant numbering, blends, HVAC safety.