Fluorocarbons: Designation and Safety Classification of Refrigerants

Designation of Refrigerants

The basis of the designation of the refrigerants fluids is based on a numbering system

Pure Fluorocarbons (HFC) refrigerants and their blends

The refrigerants are numbered with an R-, followed by the HFC-number, given by the rules of the fluorocarbons numbering system.

Isomers are identified with lower cases (ex R 134a).

HFC refrigerant blends (i.e. mixtures of pure refrigerants), are numbered after the internationally accepted ASHRAE nomenclature.

Blends having the same pure components but with different compositions are identified with upper cases (ex R 404A). Refrigerants having the form R-4xxx are zeotropic blends of two or more refrigerants, while those with the form R-5xxx are azeotropes.

The numbers are in chronological order of the refrigerant’s approval by ASHRAE.

For the GWP of Refrigerants go to FS nr18: Selecting and Using GWP values for Refrigerants

Miscellaneous organic compounds

Organic compounds are numbered with the same system as Fluorocarbons.

Example :

Propane C3H8 (R-290)
Nb of C atoms is X = 3
Nb of H atoms is Y = 8
Nb of F atoms is Z = 0
Substract 90 from 380 = 290

Inorganic compounds

Inorganic compounds shall be assigned a number in the 700 series, identification numbers are formed by adding the relative molecular mass of components to 700.

Examples:

R717 = ammonia (molecular mass 17)
R718 = water (molecular mass 18)
R744 = CO₂ (molecular mass 44)

Safety classification of refrigerants

The safety classification consists of two alphanumeric characters (e.g. A2); the capital letter corresponds to toxicity and the digit to flammability.

Toxicity classification

Refrigerants are divided into two groups according to toxicity:

• Class A signifies refrigerants for which toxicity has not been identified at concentrations less than or equal to 400 ppm
• Class B signifies refrigerants for which there is evidence of toxicity at concentrations below 400 ppm

Flammability classification

Refrigerants are divided into three groups according to flammability:

• Class 1 indicates refrigerants that do not show flame propagation when tested in air at 21°C and 101 kPa
• Class 2 indicates refrigerants having a lower flammability limit of more than 0.10 kg/m³ at 21°C and 101 kPa and a heat of combustion of less than 19 kJ/kg
• Class 3 indicates refrigerants that are highly flammable as defined by a lower flammability limit of less than or equal to 0.10 kg/m³ at 21°C and 101 kPa or a heat of combustion greater than or equal to 19 kJ/kg

Mixtures

Mixtures, whether zeotropic or azeotropic, with flammability and/or toxicity characteristics which may change as the composition changes during fractionation, shall be assigned a safety group classification based on the worst case of fractionation.

Example:

R404A is classified A1