From the ICC (International Code Council) A2L Refrigerant Related Changes

Based on the 2021 International Fire Code, Building Code, and Mechanical Code

HVAC-Related Content

The document includes updates to several model codes affecting HVAC installations, especially in relation to the safe use of A2L refrigerants (mildly flammable). Key HVAC code updates appear in the following codes:

1. International Mechanical Code (IMC):

   • Introduces definitions and scope clarifications for A2L refrigerants.

   • Includes detailed requirements for mechanical ventilation, detectors, and safety shut-off valves when using A2Ls.

   • Mandates compliance with UL 60335-2-40 and ASHRAE 15 for refrigerant system safety.

2. International Residential Code (IRC):

   • Incorporates A2L refrigerant provisions into residential settings.

   • Updates HVAC appliance installation guidelines in dwellings to include A2L use.

   • Details acceptable installation locations (e.g., not in habitable attics or closets unless specific criteria are met).

3. International Fire Code (IFC):

   • Requires refrigerant detection systems and ventilation to be installed and interlocked with HVAC equipment.

   • Addresses handling, storage, and leakage concerns, especially in commercial or mixed-use occupancies.

🧪 A2L Refrigerant-Related Content

A2L refrigerants are central to the document’s changes. Here are the main updates and safety provisions:

1. Definitions and Classifications:

   • Clearly defines A2L refrigerants and distinguishes them from A1 (non-flammable) and A3 (highly flammable) refrigerants.

   • Discusses implications of ASHRAE 34 classifications.

2. Leak Detection and Mitigation:

   • Detection systems are now required in certain occupancies or when system charge exceeds specific thresholds.

   • Must trigger mechanical ventilation or equipment shutdown.

3. Ventilation and Discharge Requirements:

   • Updates required discharge pathways and airflow rates for refrigerant release.

   • Some occupancies require dedicated mechanical ventilation systems.

4. Refrigerant Concentration Limits (RCLs):

   • Ensures installed systems keep potential leak concentrations below hazardous thresholds.

   • Aligns with ASHRAE 15 safety standards.

5. Use Location Restrictions:

   • Restrictions based on building type, room volume, and occupancy use.

   • For example, tight volume limits for use of A2L systems in residential bedrooms or sleeping areas.

6. Labeling and Signage:

   • Units using A2Ls must be clearly labeled.

   • Areas with refrigerant piping or equipment must have safety signage.

Codes Affected:

• IMC (International Mechanical Code)

• IRC (International Residential Code)

• IFGC (International Fuel Gas Code)

• IFC (International Fire Code)

• IEBC (International Existing Building Code)

• IBC (International Building Code)