Question 1

A small bolt (around 50g) is dropped from a height of roughly 30 metres on a tanker. A nearby crew member assumes it's too light to cause serious harm and doesn't react with concern.

Is this assumption correct, based on dropped-objects energy principles?

Accepted Answer

No - even small/light objects can cause fatal injury when dropped from sufficient height, due to the energy gained in the fall DROPS hazard charts demonstrate that mass and height combine to produce striking energy - even objects as light as 500g have been shown to be potentially fatal from around 10 metres, so a 50g bolt from 30 metres is far from harmless.

Question 2

Per DROPS' official Reliable Securing terminology, what is "Primary Fixing"?

Accepted Answer

The method by which an item is installed, mounted and secured to prevent it falling - e.g. bolted connections, screws, pins, buckles, clips, welds Primary Fixing is the main installation method keeping an item in place under normal conditions; DROPS defines two further layers (Secondary Retention, Safety Securing) that exist specifically to cover the case where the Primary Fixing fails.

Question 3

DROPS' Reliable Securing guidance defines THREE distinct layers of securing, not two. What are they, in order?

Accepted Answer

Primary Fixing, then Secondary Retention, then Safety Securing Secondary Retention (e.g. locking washers, locking wire, split pins) prevents loss of clamping force or displacement of the Primary Fixing's own components. Safety Securing (e.g. rated nets, baskets, wires, slings) is an additional, independent restraint where Secondary Retention isn't feasible.