UN 3358 — Refrigerating machines, containing flammable, non-poisonous, liquefied gas
Placard: Flammable Gas. ERG Guide 115. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 3358 At a Glance
UN 3358 (Refrigerating machines, containing flammable, non-poisonous…) is listed as DOT Class 2 Flammable Gas and is assigned to ERG Guide 115. Use this page to review placard data, common hazards, PPE notes, isolation context, first actions, and related UN numbers.
UN 3358 applies to refrigeration units or machinery containing flammable, non-poisonous liquefied gas refrigerants.
Hazard overview: If the sealed system leaks, flammable vapor can collect in low areas and ignite. Liquefied gas contact may cause frostbite.
Response guidance: Isolate the area, remove ignition sources, ventilate if safe and cool exposed machinery from a distance. Do not enter confined areas without SCBA.
UN 3358 Quick Details
Common Hazards of UN 3358
- 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
Complete refrigeration units or machines containing flammable, non-toxic liquefied gases such as hydrocarbons (propane, isobutane) or ammonia refrigerants. Typically metal enclosures with compressor, condenser, and evaporator components.
| Also known as | Refrigerating machinesRefrigeration equipment containing flammable gasRefrigerant-containing appliancesCooling units with flammable refrigerant |
| Appearance | Complete refrigeration units or machines containing flammable, non-toxic liquefied gases such as hydrocarbons (propane, isobutane) or ammonia refrigerants. Typically metal enclosures with compressor, condenser, and evaporator components. |
| Flash Point | Not applicable (pressurized liquefied gas within sealed system) |
| Boiling Point | Varies by refrigerant: typically -42C to -12C (-44F to 10F) for common flammable refrigerants |
| Vapor Density | Heavier than air (most flammable refrigerants 1.5-2.0 relative to air) |
| Water Reactivity | No significant reaction with water |
Fireground Response Guidance — UN 3358
Extinguishing Media
PPE Requirements
Use SCBA for leaks or fire. Wear thermal and cold-protection gloves if liquefied refrigerant contact is possible.
Isolation & Evacuation
First Actions for a UN 3358 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 may 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 3358 — Refrigerating machines, containing flammUse 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.