Peak side-on overpressure is estimated from the Cranz–Hopkinson scaled
distance Z = R / W^(1/3) (R in metres, W the TNT-equivalent charge mass in kg)
using a Brode-style curve fit, then structures are marked damaged once the
overpressure at their standoff crosses light/heavy damage thresholds.
Z = R / W^(1/3)
Pso ≈ 6.7/Z³ + 1 bar (Z < 0.3)
Pso ≈ 0.975/Z + 1.455/Z² + 5.85/Z³ − 0.019 bar (0.3 ≤ Z < 10)
shock radius(t) ≈ charge-dependent decelerating expansion
- Charge mass — TNT-equivalent explosive mass; larger charges push the same overpressure further out.
- Structure standoffs — three fixed distances from ground zero; each is colour-coded green/amber/red once the shock passes it, by damage threshold (≈7 kPa light, ≈35 kPa heavy).
- Detonate — triggers the expanding shock shell and starts the overpressure-vs-time trace.
Real safety-distance and quantity-distance tables for explosives storage are
built from exactly this scaled-distance relationship.