Military depots hold shells, missiles and explosives. The 2020 Beirut ammonium-nitrate blast (2,750 t, 3 kt TNT) killed 220 and injured 6,500. NFPA 495 and DoD 6055.09 use IMESAFR (Quantity Distance) to set separation distances.
NET Explosive Weight
- Class 1.1: Mass detonation (TNT)
- Class 1.2: Projectile risk
- Class 1.3: Mass fire
- Class 1.4: Moderate (small arms)
- TNT equivalent: Explosive x factor
IMESAFR Quantity Distance
- Inhabited Building Distance (IBD): K40 m
- Public Traffic Route (PTR): K24
- Magazine-to-Magazine (IMD): K11
- D = K * W^(1/3): Scaled distance
- Example: 1000 kg TNT -> IBD 400 m
Depot Barriers
- Earth-covered magazine (ECM): 3 m earth
- Barricade: 3:2:1 earth wall
- Sprinkler: Class 1.3 needs 12.2 L/min/m2
- Ex electrical: Zone 1 throughout interior
- Lightning: API 2003 + mil spec
Ammonium Nitrate Risk
- Oxidizer Class III: FGAN
- Auto-decomp: 170 C
- Contamination: Organic + fuel = explosive
- Segregation: 30+ m distance
- Sprinkler: 20.4 L/min/m2 oxidizer
Historic Incidents
- Beirut 2020: 2,750 t AN - 220 dead
- Tianjin 2015: Chemical - 173 dead
- West TX 2013: Fertilizer - 15 dead
- Elazig Sivrice 2023: Controlled destruction
- Afyon April 2009: MKE - 16 martyred
Munitions with SprinkCalc
SprinkCalc sizes munition IMESAFR K-scaled distance, ammonium nitrate sprinkler 20.4 L/min/m2, earth-covered magazine and NFPA 495 layout.
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Sources & Further Reading
NFPA 495, DoD 6055.09, NATO AASTP-1, IMESAFR, OSHA 1910.109. NFPA 495 Explosive Materials Code.