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Scaled distance (Hopkinson-Cranz)

Cube-root scaled distance Z = R / W^(1/3), the canonical first parameter for blast standoff and civil-protection planning.

Civil-protection / accidental-explosion scope only (UFC 3-340-02, public release). Weapon-effects and penetration calculations are out of scope.

Inputs

Unit system

Standoff distance Rm

Equivalent TNT charge Wkg

Results

W^(1/3) —

Scaled distance Z — m/kg^(1/3)

Citations and assumptions

Z Z = R / W^(1/3) — Hopkinson-Cranz cube-root scaling. UFC 3-340-02 (Approved for Public Release).

TNT W must already be expressed as equivalent TNT mass. Use the TNT-equivalent tool first if your charge is another explosive.

Engine: blast.js v0.1.0 · Code pack: — (country-independent) · Date:

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Preliminary calculation tool. Results are for preliminary sizing and cross-check only. Final design, sealed responsibility, and permit submissions require the full official text of the referenced regulations and the review of a licensed engineer.