☣️ UN 1147 • CLASS 3

UN 1147 — Decahydronaphthalene

Placard: Flammable. ERG Guide 130. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.

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⚠️ This page is a quick-reference aid. For real incidents: stage upwind, isolate, deny entry, request Hazmat early, and consult the current ERG + SOP/SOG.

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.

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UN 1147 Quick Details

UN 1147
Product name: Decahydronaphthalene
DOT Class: 3
Placard type: Flammable
ERG Guide: 130 (check current ERG)
Initial isolation: ERG 130: isolate spill 50m all directions; if tank/rail car involved in fire, isolate 800m all directions

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 asDecalinBicyclo[4.4.0]decaneNaphthanePerhydronaphthalene
CAS Number91-17-8
AppearanceColorless liquid with a mild, aromatic odor. Exists as cis and trans isomers. Oily consistency at room temperature.
Flash Point58C (136F)
Boiling Point189-196C (372-385F) depending on isomer
Vapor Density4.8 (much heavier than air)
Water ReactivityNo significant reaction; insoluble in water
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.

Fireground Response Guidance — UN 1147

Extinguishing Media

Alcohol-resistant foam, CO2, dry chemical, water spray for cooling

PPE Requirements

⚠️ Level B minimum in vapor areas; SCBA required in confined spaces or heavy vapor; chemical-resistant gloves and suit

Emergency responders should wear Level B protective equipment, including SCBA, and chemical-resistant gloves and suits to minimize exposure to decahydronaphthalene vapors.

Isolation & Evacuation

ERG 130: isolate spill 50m all directions; if tank/rail car involved in fire, isolate 800m all directions
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 130).

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).
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📋 Copy & Share Field Card

UN 1147 — Decahydronaphthalene
HAZMAT RADIO NOTE — UN 1147 Product: Decahydronaphthalene Class 3 / Flammable / ERG 130 PPE: Level B minimum in vapor areas; SCBA required in confined spaces or heavy vapor; chemical-resistant gloves and suit ISOLATION: ERG 130: isolate spill 50m all directions; if tank/rail car involved in fire, isolate 800m all directions ACTION: Stage upwind · Isolate · Deny entry · Request HazmatRADIO

Use for: Quick radio or face-to-face size-up. Short, structured, field-ready.

SMS WhatsApp
=== IC HAZMAT BRIEFING === UN 1147 — Decahydronaphthalene Class: 3 | Placard: Flammable | ERG Guide: 130 Appearance: Colorless liquid with a mild, aromatic odor. Exists as cis and trans isomers. Oily consistency at room temperature. Water Reactivity: No significant reaction; insoluble in water Extinguishing: Alcohol-resistant foam, CO2, dry chemical, water spray for cooling PPE: Level B minimum in vapor areas; SCBA required in confined spaces or heavy vapor; chemical-resistant gloves and suit Isolation: ERG 130: isolate spill 50m all directions; if tank/rail car involved in fire, isolate 800m all directions — Key Hazards — • 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. — First Actions — • 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. SOURCE: allfirefighter.com/hazmat/un/1147 | Always use current ERG + SOP/SOGIC BRIEFING

Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.

SMS (short)
UN1147 Decahydronaphthalene Cls3 ERG130 | ERG 130: isolate spill 50m all directions; if tank/rail car involved in fire, is | allfirefighter.com/hazmat/un/1147SMS / 160 CHAR

Use for: Quick text to command or incoming units. Fits in a single SMS.

⚠️ Quick-reference only. Always use current ERG + SOP/SOG for incident-specific actions. Page: https://allfirefighter.com/hazmat/un/decahydronaphthalene-un-1147

Related UN Numbers in Class 3

Discovery block for training / quick reference. Always consult the current ERG + your SOP/SOG for operations.
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Frequently Asked Questions about UN 1147

Yes, UN 1147 decahydronaphthalene is highly flammable and can be easily ignited by heat, sparks, or flames.

The recommended isolation distance for UN 1147 is 50m in all directions, with an isolation distance of 800m in all directions if a tank or rail car is involved in a fire.

Alcohol-resistant foam, CO2, dry chemical, and water spray for cooling are approved extinguishing agents for UN 1147 fires.
Sources (high level): DOT/PHMSA marking & class concepts + ERG usage principles. This page does not reproduce ERG guide text—always consult the current ERG for incident-specific protective actions.