Time rules
| Rule | Measured value |
|---|---|
| Validity | One shift |
| Daily limit for the same party | 11 hours |
| Number of extensions | 6 at most |
| Shifts on one form | 7 at most; a new form on the eighth |
| Party change threshold | More than a third closes the permit |
| Break | A day or more closes the permit |
The emergency rule
When the emergency plan is activated, every active permit becomes void. That rule decides whether anyone knows who is where during an evacuation: work cannot restart until permits are closed, so the list of open permits is the backbone of the post-evacuation head count.
Breaks do not close a permit
Tea and meal breaks did not require renewal; the area was left in a made-safe state. The distinction is this: if work stops but the site stays in the same condition, the permit survives; if the condition changes, a new permit is needed.
The hidden cost of extensions
On paper an extension means adding another signature to the same form. By the third shift a single sheet carries more than a dozen signatures, and both its legibility and the question of who is accountable become blurred. The time rules can be right while the medium fails at exactly this point.
Why the party change has a threshold
Once more than a third of the party has changed, the number of people who never heard the toolbox talk becomes critical. The threshold protects the answer to "who knows what"; it measures shared knowledge rather than headcount.