UN 3340 — Refrigerant gas R-407C
Placard: Non-Flammable Gas. ERG Guide 126. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 3340 is Refrigerant gas R-407C, a non-flammable liquefied refrigerant gas assigned to ERG Guide 126. Asphyxiation, frostbite and HF fire products are key concerns.
Hazard overview: Non-flammable liquefied refrigerant gas; pressure release, frostbite and asphyxiation are primary hazards. Vapors are heavier than air and can collect in low or confined areas, displacing oxygen. Liquefied gas contact can cause frostbite or cold burns.
Response guidance: For UN 3340, isolate low/confined areas, ventilate only after monitoring and use SCBA. Cool cylinders from protection and watch for frostbite and asphyxiation hazards.
Firefighter training notes: Training for UN 3340 should emphasize product verification, SCBA use, exposure control, decontamination, runoff containment and SDS/shipping paper review. Use ERG 126, SDS and local SOP.
Regulatory context: Refrigerant gas R-407C is regulated as a hazardous material for transport and emergency response. Storage, reporting, exposure, waste and incident-notification duties depend on quantity, package type, formulation and jurisdiction; verify shipping papers, SDS and authority guidance.
Storage & handling: Refrigerant gas R-407C cylinders should be secured upright in a cool, ventilated area away from heat, physical damage and confined low spaces, with leak response and oxygen monitoring plans.
UN 3340 Quick Details
Common Hazards of UN 3340
- Non-flammable liquefied refrigerant gas; pressure release, frostbite and asphyxiation are primary hazards.
- Vapors are heavier than air and can collect in low or confined areas, displacing oxygen.
- Liquefied gas contact can cause frostbite or cold burns.
- Cylinders exposed to fire may vent, rupture or rocket.
- Fire or hot surfaces may decompose refrigerant into hydrogen fluoride and other toxic/corrosive fluorinated products.
- Ventilation and oxygen monitoring are critical before entering low or enclosed spaces.
- Exact blend and cylinder condition should be verified from labels and SDS.
Chemical Identity & Physical Properties
Colorless, liquefied gas with slight ethereal odor. Shipped as a pressurized liquid blend of three hydrofluorocarbons. Heavier than air.
| Also known as | R-407CHFC-407CDifluoromethane/Pentafluoroethane/Tetrafluoroethane blendR-32/R-125/R-134a mixture |
| CAS Number | 75-68-3 |
| Appearance | Colorless, liquefied gas with slight ethereal odor. Shipped as a pressurized liquid blend of three hydrofluorocarbons. Heavier than air. |
| Flash Point | Not applicable (non-flammable gas) |
| Boiling Point | -43.6C (-46.5F) |
| Vapor Density | 3.0 (heavier than air) |
| Water Reactivity | No significant reaction with water |
Fireground Response Guidance — UN 3340
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for releases, fire or confined spaces. Wear eye/face protection and insulated gloves for liquefied-gas frostbite risk.
Isolation & Evacuation
First Actions for a UN 3340 Incident
- Call 911 and the emergency response number on the shipping paper, if available.
- Keep unauthorized personnel away and establish incident command.
- Stay upwind, uphill and upstream.
- Avoid breathing vapor, dust, gas, mist, smoke or aerosols and avoid skin or eye contact.
- Do not touch damaged containers, cylinders, packages or spilled material without proper training and PPE.
- Prevent contaminated liquid, dust, runoff, residue and decontamination waste from spreading.
- Ventilate confined spaces only after monitoring and only if properly trained and equipped.
- Use ERG Guide 126, SDS, shipping papers and monitoring to set isolation, evacuation and entry decisions.
📋 Copy & Share Field Card
UN 3340 — Refrigerant gas R-407CUse for: Quick radio or face-to-face size-up. Short, structured, field-ready.
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
Use for: Quick text to command or incoming units. Fits in a single SMS.