A2L Refrigerants Introduction : 2 Characteristics of A2L Refrigerants

 ASHRAE Classification System:

• Toxicity:

• A = low toxicity, B = high toxicity.

• Flammability:

• 1 = non-flammable, 2 = low flammability, 3 = high flammability.

• Safest refrigerant: A1 (non-flammable, low toxicity).

• Most dangerous refrigerant: B3 (high flammability, high toxicity).

• A2L refrigerants have low flammability and low toxicity.

Toxicity of A2L Refrigerants:

• Routes of exposure: inhalation, skin contact, ingestion.

• Occupational Exposure Limit (OEL):

• Refrigerants in the A classification have an OEL ≥ 400 PPM, making them less toxic.

• Toxicity depends on molecular structure, exposure routes, concentration, and both short- and long-term exposure.

Flammability of A2L Refrigerants:

• The "L" in A2L stands for Low Burning Velocity (burns at less than 10 cm/sec).

• Lower Flammable Limit (LFL): Minimum concentration needed to ignite.

• Upper Flammable Limit (UFL): Maximum concentration that can support combustion.

• A2L refrigerants typically have an LFL below 3% and UFL above 17%.

• Minimum Ignition Energy (MIE): Energy required to ignite a flammable substance.

Burning Velocity & Heat of Combustion:

• Burning velocity: Rate at which a flame spreads through the refrigerant.

• Heat of combustion (HOC): Amount of energy released as heat during combustion.

Safety Measures:

• A2L refrigerants are generally safe with proper handling and adherence to safety guidelines.