UN 1147 — Decahydronaphthalene
Placard: Flammable. ERG Guide 130. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
Decahydronaphthalene is a highly flammable liquid that can be easily ignited by heat, sparks, or flames. It is a colorless liquid with a mild, aromatic odor and exists as cis and trans isomers.
Hazard overview: Decahydronaphthalene is highly flammable and can form explosive mixtures with air, posing a significant risk of fire and explosion. Prolonged exposure to decahydronaphthalene vapors can also cause respiratory problems and other health issues.
Response guidance: In the event of a decahydronaphthalene spill, it is essential to take immediate action to prevent ignition and minimize exposure. Emergency responders should wear Level B protective equipment, including SCBA, and use alcohol-resistant foam or other approved extinguishing agents to control the fire.
UN 1147 Quick Details
Common Hazards of UN 1147
- HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames.
- Vapors may form explosive mixtures with air.
- Vapors may travel to source of ignition and flash back.
- Most vapors are heavier than air. They will spread along the ground and collect in low or confined areas
- Vapor explosion hazard indoors, outdoors or in sewers.
- Those substances designated with a (P) may polymerize explosively when heated or involved in a fire.
- Runoff to sewer may create fire or explosion hazard.
- Containers may explode when heated.
Chemical Identity & Physical Properties
Decahydronaphthalene is a colorless liquid with a mild, aromatic odor and an oily consistency at room temperature.
| Also known as | DecalinBicyclo[4.4.0]decaneNaphthanePerhydronaphthalene |
| CAS Number | 91-17-8 |
| Appearance | Colorless liquid with a mild, aromatic odor. Exists as cis and trans isomers. Oily consistency at room temperature. |
| Flash Point | 58C (136F) |
| Boiling Point | 189-196C (372-385F) depending on isomer |
| Vapor Density | 4.8 (much heavier than air) |
| Water Reactivity | No significant reaction; insoluble in water |
Fireground Response Guidance — UN 1147
Extinguishing Media
PPE Requirements
Emergency responders should wear Level B protective equipment, including SCBA, and chemical-resistant gloves and suits to minimize exposure to decahydronaphthalene vapors.
Isolation & Evacuation
First Actions for a UN 1147 Incident
- Keep unauthorized personnel away.
- Stay upwind, uphill and/or upstream.
- Ventilate closed spaces before entering, but only if properly trained and equipped.
- Isolate spill or leak area for at least 50 meters (150 feet) in all directions.
- Consider initial downwind evacuation for at least 300 meters (1000 feet).
📋 Copy & Share Field Card
UN 1147 — DecahydronaphthaleneUse 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.