General Description

Refrigerant Gas R404A is a colorless odorless mixture of three hydrofluorocarbon compounds in near-azeotropic proportions.
It was designed to replace R-502 and R-22 used in commercial refrigerator equipment for low and medium temperature ranges. Its properties make it ideal for use in display cases, refrigerated vehicles, ice makers, and other applications.
Azeotropic mixtures have sharp boiling points instead of boiling over a range of temperatures, which is the case with most mixtures. Bp (at 1 atm) -46.5°C. Density (as a liquid) 0.485 kg/L. Shipped as a liquid under its own vapor pressure. The vapors are heavier than air and can cause asphyxiation by the displacement of air. Contact with the liquid can cause frostbite. Prolonged exposure to fire or intense heat may cause the containers to rupture violently and rocket.

Air & Water Reactions
No rapid reaction with air. No rapid reaction with water.
Fire Hazard
Excerpt from ERG Guide 126 [Gases - Compressed or Liquefied (Including Refrigerant Gases)]:
Some may burn but none ignite readily. Containers may explode when heated. Ruptured cylinders may rocket.
CAUTION: Aerosols (UN1950) may contain a flammable propellant. (ERG, 2020)
Health Hazard
Excerpt from ERG Guide 126 [Gases - Compressed or Liquefied (Including Refrigerant Gases)]:

Vapors may cause dizziness or asphyxiation without warning. Vapors from liquefied gas are initially heavier than air and spread along ground. Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite. Fire may produce irritating, corrosive and/or toxic gases. (ERG, 2020)

Reactivity Profile
Refrigerant Gas R404A is a blend of CF3CHF2 (R-125, 44% by mass), CF3CH3 (R-143A, 52%) and CH2FCF3 (R-134A, 4%). Non-combustible, but toxic gases can be produced by thermal decomposition in a fire.


Source: https://cameochemicals.noaa.gov/chemical/26023#:~:text=Refrigerant%20Gas%20R404A%20is%20a%20blend%20of%20CF3CHF2%20(R%2D125,thermal%20decomposition%20in%20a%20fire.