R-456A
For R-456A, ashrae safety class is A1, verified against its source on 2026-08-11.
- Refrigerant
- R-456A verified
- ASHRAE safety class
- A1 verified
- Retrofit / new
- retrofit per federalregister.gov
- Listing status / notes
- acceptable, subject to use conditions per federalregister.gov
What the source says
ASHRAE 34-2024 categorizes HFO-1234yf and R-444A as being in the A2L Safety Group and R-453A, R-456A, and R-480A in the A1 Safety Group.
— federalregister.gov, retrieved 2026-08-11
What federalregister.gov says
List the blend R-456A as acceptable, subject to use conditions, in retrofit LMDV MVACs, retrofit HD pickup trucks and van MVACs (complete and incomplete), retrofit HDOH MVACs, and retrofit MVACs on buses and trains;
— federalregister.gov, retrieved 2026-08-11
Source
- federalregister.govhttps://www.federalregister.gov/documents/2025/11/10/2025-19812/protection-of-stratospheric-ozone-listing-of-substitutes-under-the-significant-new-alternatives