UN 3252 — Refrigerant gas R-32
Placard: Flammable Gas. ERG Guide 115. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 3252 Refrigerant gas R-32 is assigned to ERG Guide 115 for initial emergency response. Colorless, odorless gas at room temperature. Shipped as a liquefied compressed gas under pressure. Verify the exact product from shipping papers and SDS before selecting tactics.
Hazard overview: Primary hazards: an extremely flammable gas; vapors may form explosive mixtures and cylinders may rocket if heated. EXTREMELY FLAMMABLE. Will be easily ignited by heat, sparks or flames.
Response guidance: For a UN 3252 incident, isolate the area, keep unauthorized personnel away, stay upwind/uphill and confirm the exact material from shipping papers and SDS. Eliminate ignition sources and use the listed extinguishing media; for burning gas, do not extinguish unless the leak can be stopped. Follow ERG Guide 115 and local incident command procedures.
UN 3252 Quick Details
Common Hazards of UN 3252
- EXTREMELY FLAMMABLE.
- Will be easily ignited by heat, sparks or flames.
- Will form explosive mixtures with air.
- Vapors from liquefied gas are initially heavier than air and spread along ground.
- Vapors may travel to source of ignition and flash back.
- Cylinders exposed to fire may vent and release flammable gas through pressure relief devices.
- Containers may explode when heated.
- Ruptured cylinders may rocket.
Chemical Identity & Physical Properties
Colorless, odorless gas at room temperature. Shipped as a liquefied compressed gas under pressure.
| Also known as | DifluoromethaneHFC-32Methylene fluorideR-32CH2F2 |
| CAS Number | 75-10-5 |
| Appearance | Colorless, odorless gas at room temperature. Shipped as a liquefied compressed gas under pressure. |
| Flash Point | Not applicable (gas) |
| Boiling Point | -51.7C (-61F) |
| Vapor Density | 1.8 (heavier than air) |
| Water Reactivity | No significant reaction with water |
Fireground Response Guidance — UN 3252
Extinguishing Media
PPE Requirements
Level B minimum; SCBA required; cold-resistant gloves for handling liquefied gas to prevent frostbite
Isolation & Evacuation
First Actions for a UN 3252 Incident
- CALL 911. Then call the emergency response telephone number on the shipping paper if available.
- Keep unauthorized personnel away.
- Stay upwind, uphill and/or upstream.
- Many gases are heavier than air and will spread along the ground and collect in low or confined areas.
- Isolate spill or leak area for at least 100 meters (330 feet) in all directions.
- Consider initial downwind evacuation for at least 800 meters (1/2 mile).
📋 Copy & Share Field Card
UN 3252 — Refrigerant gas R-32Use 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.