Refrigerant classification

The ISO 817 and ANSI / ASHRAE 34 standards are safety classifications for refrigerants.

The toxicity rating is divided into two groups, Low Toxicity A and Low Toxicity B.

The flammability of a refrigerant is divided into four categories according to these standards, with Class 1 being virtually incombustible under most conditions of use. R 410A and R 22 both in Class 1 are considered virtually non-combustible.

Class 2L (L = low) is considered to be low flammability, classified as having low combustion rate and having lower heat of combustion. Class 2 and Class 3 designate flammable and highly flammable refrigerants. R 152a is a class 2 refrigerant, while the hydrocarbons (propane, butane) are classified as highly flammable class 3 refrigerants. 

ISO 817 Refrigerant Classification Scheme

Safety Classes for Refrigerants

Safety classes for refrigerants are categorized based on their flammability and toxicity:

• A1: Non-flammable and low toxicity
• A2L: Mildly flammable and low toxicity
• A3: Highly flammable and low toxicity
• B2L: Mildly flammable and higher toxicity

Examples of Refrigerants and Their Safety Classes

Natural Refrigerants:

• R744 (CO2): A1
• R717 (Ammonia): B2L
• R290 (Propane): A3
• R600a (Isobutane): A3

Synthetic Refrigerants:

• R404A: A1 (Banned in the EU since 2020 under F-Gas Regulation)
• R410A: A1 (No long-term future)
• R134a: A1 (Transitional refrigerant)
• R32: A2L (Suitable for transition)
• R1234yf: A2L (Future-proof)
• R1234ze: A2L (Future-proof)
• R407C: A1 (Suitable for transition)
• R448A: A1 (Transitional refrigerant)
• R449A: A1 (Transitional refrigerant)
• R513A: A1 (Transitional refrigerant)

The safety class of a refrigerant provides important information about its flammability and toxicity, which is crucial for safe handling and application in refrigeration and air conditioning systems.