☣️ UN 1727 • CLASS 8
Ammonium hydrogendifluoride, solid
Placard: Corrosive. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
🚒☣️
⚠️ 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.
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Quick details
UN 1727
Class: 8
Placard type: Corrosive
ERG: Guide 154 (check current ERG)
Isolation: ERG 154: Initial isolation 50m in all directions. Spill: daytime 100m, nighttime 200m downwind. Fire: evacuate 800m radius if tank/railcar involved.
Chemical & Response Details
| Also known as | Ammonium bifluorideAmmonium hydrogen fluorideAmmonium acid fluorideABF |
| CAS Number | 1341-49-7 |
| Appearance | White crystalline solid or powder with a sharp, pungent odor. Deliquescent (absorbs moisture from air). |
| Flash Point | Not applicable (non-flammable solid) |
| Boiling Point | Decomposes at 240C (464F) releasing hydrogen fluoride gas |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Soluble in water, forming acidic and corrosive solution. Hydrolyzes to release hydrogen fluoride in moist conditions. |
| Extinguishing | Dry chemical, CO2, or dry sand. Water spray may be used to cool containers but avoid direct contact with material. |
| PPE | ⚠️ Level B minimum required. Full face SCBA, acid-resistant suit, neoprene or butyl rubber gloves. Avoid all skin and eye contact due to severe burn hazard from fluoride. |
| Isolation | ERG 154: Initial isolation 50m in all directions. Spill: daytime 100m, nighttime 200m downwind. Fire: evacuate 800m radius if tank/railcar involved. |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Common hazards (high level)
- TOXIC and/or CORROSIVE; inhalation, ingestion or skin contact with material may cause severe injury
- Contact with molten substance may cause severe burns to skin and eyes.
- Avoid any skin contact.
- Fire may produce irritating, corrosive and/or toxic gases.
- Runoff from fire control or dilution water may be corrosive and/or toxic and cause environmental
- Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive
- Some are oxidizers and may ignite combustibles (wood, paper, oil, clothing, etc.).
- Corrosives in contact with metals may evolve flammable hydrogen gas.
First actions (field-minded)
- CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper
- 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 in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters
- For highlighted materials: see Table 1 - Initial Isolation and Protective Action Distances.
- For non-highlighted materials: increase the immediate precautionary measure distance, in the downwind
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UN 1727 — Ammonium hydrogendifluoride, solid HAZMAT RADIO NOTE — UN 1727
Product: Ammonium hydrogendifluoride, solid
Class 8 / Corrosive / ERG 154
PPE: Level B minimum required. Full face SCBA, acid-resistant suit, neoprene or butyl rubber gloves. Avoid all skin and eye contact due to severe burn hazard from fluoride.
ISOLATION: ERG 154: Initial isolation 50m in all directions. Spill: daytime 100m, nighttime 200m downwind. Fire: evacuate 800m radius if tank/railcar involved.
ACTION: Stage upwind · Isolate · Deny entry · Request HazmatRADIO
Use for: Quick radio or face-to-face size-up. Short, structured, field-ready.
=== IC HAZMAT BRIEFING ===
UN 1727 — Ammonium hydrogendifluoride, solid
Class: 8 | Placard: Corrosive | ERG Guide: 154
Appearance: White crystalline solid or powder with a sharp, pungent odor. Deliquescent (absorbs moisture from air).
Water Reactivity: Soluble in water, forming acidic and corrosive solution. Hydrolyzes to release hydrogen fluoride in moist conditions.
Extinguishing: Dry chemical, CO2, or dry sand. Water spray may be used to cool containers but avoid direct contact with material.
PPE: Level B minimum required. Full face SCBA, acid-resistant suit, neoprene or butyl rubber gloves. Avoid all skin and eye contact due to severe burn hazard from fluoride.
Isolation: ERG 154: Initial isolation 50m in all directions. Spill: daytime 100m, nighttime 200m downwind. Fire: evacuate 800m radius if tank/railcar involved.
— Key Hazards —
• TOXIC and/or CORROSIVE; inhalation, ingestion or skin contact with material may cause severe injury
• Contact with molten substance may cause severe burns to skin and eyes.
• Avoid any skin contact.
— First Actions —
• CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper
• Keep unauthorized personnel away.
• Stay upwind, uphill and/or upstream.
• Ventilate closed spaces before entering, but only if properly trained and equipped.
SOURCE: allfirefighter.com/hazmat/un/1727 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN1727 Ammonium hydrogendifluoride, solid Cls8 ERG154 | allfirefighter.com/hazmat/un/1727SMS / 160 CHAR
Use for: Quick text to command or incoming units. Fits in a single SMS. Includes link to full page.
⚠️ Quick-reference only. Always use current ERG + SOP/SOG for incident-specific actions. Page: https://allfirefighter.com/hazmat/un/1727
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FAQ
TOXIC and/or CORROSIVE; inhalation, ingestion or skin contact with material may cause severe injury Contact with molten substance may cause severe burns to skin and eyes. Avoid any skin contact. Fire may produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may be corrosive and/or toxic and cause environmental Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive Some are oxidizers and may ignite combustibles (wood, paper, oil, clothing, etc.). Corrosives in contact with metals may evolve flammable hydrogen gas.
CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper Keep unauthorized personnel away. Stay upwind, uphill and/or upstream.
Level B minimum required. Full face SCBA, acid-resistant suit, neoprene or butyl rubber gloves. Avoid all skin and eye contact due to severe burn hazard from fluoride.
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 154 and your department SOP/SOG for incident-specific protective actions.
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.