OFFSHORE TOOLKIT · CALCULATOR 05

Dropped Object Consequence Calculator

Same methodology as the DROPS Calculator this plots an object's mass against its fall height to classify the likely consequence of a dropped object incident. A guide only; not a substitute for a full risk assessment.

Equipment / item name (optional, shown on the printed report)

Fall height (to solid deck/ground — don't subtract a person's height)

Object mass

Assumes full PPE is worn and the object is blunt (no sharp edges — a sharp or pointed object gives a worse outcome than shown). Chart and classification cover 0.1–10kg; below 0.1kg, skin puncture risk becomes the dominant factor rather than blunt trauma.

POTENTIAL OUTCOME

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Impact energy—

40J rule—

Consequence chart

Mass (kg) vs fall height (m), banded by likely outcome. Marker shows your current input. Chart range: 0.1–10kg, 0–15m.

Slight (first aid)

Minor (recordable)

Major (lost time / DAFWC)

Fatality

Quick reference — DROPS Calculator

Outcome definitions

Fatality — death resulting from an injury or trauma
Major — Lost Time Incident / Days Away From Work Case (DAFWC): non-fatal injury causing loss of time beyond the day it occurred
Minor — Medical Treatment Case: injury needing treatment beyond first aid, no lost time
Slight — First Aid Case: limited or no injury

The 40 Joule rule

Any blunt object reaching 40 Joules or more of fall energy is likely to cause a Recordable incident or worse on an unprotected person
Example from the source calculator: a 200g bolt falling 27m ≈ 53J (0.2kg × 27m × 9.8066m/s²)
This is a quick rule of thumb alongside the mass/height classification, not a replacement for it

Considerations

Assumes standard PPE (hard hat, safety boots, eye protection) and a blunt object
Not compatible with sharp objects like broken glass or metal shards — outcome would be worse
Even a small object falling from height can be lethal in reality — this is a guide, not a guarantee

Purpose

Common benchmark for classifying potential consequences of a dropped object, following the DROPS Calculator methodology recognised by HSE organisations
Used in task planning, risk assessment, and incident reporting
Also useful during design for positioning, fixtures, and securing items at height