Understanding Refrigerant Designation per ANSI/ASHRAE 34-2019

The ANSI/ASHRAE Standard 34, titled "Designation and Safety Classification of Refrigerants," provides a uniform system for assigning reference numbers and safety classifications to refrigerants. This standard helps in clearly identifying different refrigerants and their safety properties.

Refrigerant Nomenclature Series

The standard assigns identifying numbers based on the chemical composition and properties of the refrigerant. Different series numbers are used for different types of refrigerants:

• 100 series: Typically single-component hydrofluorocarbons (HFCs).
• 200 series: Typically single-component fluorocarbons containing chlorine (CFCs).
• 300 series: Typically single-component hydrochlorofluorocarbons (HCFCs).
• 400 series: Assigned to Zeotropic mixtures.
• 500 series: Assigned to Azeotropic mixtures.
• 600 series: Assigned to organic compounds.
• 700 series: Assigned to inorganic compounds.
• 1000 series: Assigned to unsaturated organic compounds (e.g., olefins).

Zeotropic Mixtures and the 400 Series

A zeotropic mixture, also known as a non-azeotropic mixture, is a blend of two or more refrigerants that evaporate or condense over a range of temperatures at a constant pressure. Unlike azeotropic mixtures, the composition of the vapor phase and liquid phase of a zeotropic mixture is different.

According to ANSI/ASHRAE 34-2019, Zeotropic mixtures are specifically assigned identifying numbers within the 400 series.

For example, R-410A and R-407C are common zeotropic refrigerant mixtures, and their designations start with 400.

Therefore, based on the ANSI/ASHRAE 34-2019 standard for Designation and Safety Classification of Refrigerants, Zeotropic mixtures are assigned an identifying number in the 400 series.