A lock-out/tag-out trainer on a pressurised line. Valves take sustained effort and spring back if you let go early, and the line only bleeds down once both ends are shut. Unsafe acts are recorded rather than prevented, so a trainee can finish the whole procedure and still fail it.
How we built it
A captured place shows how something looked. A procedure needs parts that move, resist and read out, so the panel is built geometry with a simulated process behind it: valve travel, line pressure and the status lamp.
A valve needs about 1.6 s of sustained effort and springs back to open in 0.45 s if released early. Driven fully home it latches, as a gate valve does. Closing one is a decision you have to hold, not a click.
Pressure only falls once both ends are shut, taking 4.28 s to drop from 5.98 bar to the 0.2 bar safe mark, and rises again if a valve is reopened. The gauge has to be read before locking off, because the reading is the evidence.
Locking a live line is allowed to happen and is written down as a fault. A trainer that prevents mistakes teaches nothing about them; one that records them can show you what you did.
Across four scripted runs: a correct run completes 5/5 and passes; locking a live line and recording a false verification both complete 5/5 and fail; skipping the lock finishes 4/5 and fails. Completing every step is not the same as doing it safely.
Limits