UN 1973 — Chlorodifluoromethane and chloropentafluoroethane mixture
Placard: Non-Flammable Gas. ERG Guide 126. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1973 is Chlorodifluoromethane and chloropentafluoroethane mixture, a non-flammable liquefied compressed refrigerant gas assigned to ERG Guide 126. The main concerns are pressure, oxygen displacement, frostbite and toxic decomposition in fire.
Hazard overview: NON-FLAMMABLE liquefied compressed refrigerant gas; pressure and asphyxiation hazards are primary. Heavy vapor may collect in low or confined areas and displace oxygen. Contact with liquefied gas may cause frostbite or cold burns.
Response guidance: For a UN 1973 incident, verify the product with shipping papers, container markings, SDS and ERG Guide 126. Establish incident command, isolate the area, stay upwind, control ignition or downwind hazards, cool exposed containers from a protected distance when appropriate and base entry decisions on monitoring and local SOP.
Firefighter training notes: Training for UN 1973 should emphasize pressure hazards, oxygen displacement, frostbite, cylinder rupture/rocket risk, ventilation and atmospheric monitoring. Use ERG 126, SDS and local SOP.
Regulatory context: Chlorodifluoromethane and chloropentafluoroethane mixture is regulated as a hazardous material for transportation and emergency response purposes. Storage, workplace exposure, emergency planning, spill reporting and waste handling requirements vary by exact product, concentration, quantity and jurisdiction. Verify current requirements through shipping papers, SDS, container markings and applicable DOT, OSHA, EPA, NFPA, state or local authority guidance.
Storage & handling: Chlorodifluoromethane and chloropentafluoroethane mixture cylinders should be secured in a cool, ventilated area away from heat, physical damage and incompatible materials. Prevent leaks into confined or low areas and follow SDS and refrigerant cylinder requirements.
UN 1973 Quick Details
Common Hazards of UN 1973
- NON-FLAMMABLE liquefied compressed refrigerant gas; pressure and asphyxiation hazards are primary.
- Heavy vapor may collect in low or confined areas and displace oxygen.
- Contact with liquefied gas may cause frostbite or cold burns.
- Containers may rupture or rocket when heated.
- Fire or hot surfaces may decompose refrigerant and produce toxic/corrosive gases such as hydrogen halides.
- Vapor may cause dizziness or unconsciousness in poorly ventilated spaces.
- Specific refrigerant hazards should be confirmed from SDS and cylinder markings.
Chemical Identity & Physical Properties
Colorless liquefied compressed gas with faint ethereal odor. Heavier than air as vapor. Stored under pressure in cylinders.
| Also known as | R-502Refrigerant 502HCFC-22/CFC-115 mixtureAzeotropic refrigerant blendGenetron 502 |
| Appearance | Colorless liquefied compressed gas with faint ethereal odor. Heavier than air as vapor. Stored under pressure in cylinders. |
| Flash Point | Not applicable (non-flammable gas) |
| Boiling Point | -45°C (-49°F) at atmospheric pressure |
| Vapor Density | 3.5 (air = 1) - heavier than air, vapors collect in low areas |
| Water Reactivity | No significant reaction with water. Slightly soluble in water. |
Fireground Response Guidance — UN 1973
Extinguishing Media
PPE Requirements
Use SCBA and oxygen monitoring in confined or oxygen-deficient areas. Wear face shield, insulated or cryogenic gloves and protective clothing when liquefied or refrigerated gas contact is possible.
Isolation & Evacuation
First Actions for a UN 1973 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.
- Avoid breathing vapors, gas, smoke, mist or dust and avoid skin or eye contact.
- Do not touch damaged containers or spilled/released material unless properly trained and wearing appropriate protective equipment.
- Ventilate closed spaces before entering, but only if properly trained, equipped, monitored and authorized by incident command.
- Isolate the release or spill area and expand the perimeter for fire involvement, vapor accumulation, cylinder/tank heating or unknown product identity.
- Use ERG Guide 126, shipping papers, SDS, air monitoring and incident command for protective actions.
📋 Copy & Share Field Card
UN 1973 — Chlorodifluoromethane and chloropentafluUse 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.