General rule: PNBs are diagrammed to allow a break away from the cab environment.
DRI2 1.3.1
Wherever possible: a clear 30-minute break will be diagrammed.
DRI2 1.3.1.1
Turns over ADLT 08:45: a full 30-minute break will be diagrammed.
DRI2 1.3.1.1.1
2 × 20-minute breaks: may only be diagrammed for turns under 08:45, unless agreed locally with the relevant LLC.
DRI2 1.3.1.2
Up to 5h 59m: the PNB may be anywhere in the turn, including at the start or finish.
DRI2 1.3.1.3
6h and above: the PNB must not be before any work is undertaken or once all work has been completed.
DRI2 1.3.1.3
Midpoint rule: for 6h+ turns, the single PNB, or one of the 2 PNBs where 2 × 20 is used, will be within the 2-hour limit of the midpoint where this does not increase the overall number of diagrams required.
DRI2 1.3.1.3
Walking / mobilising time: all PNBs are exclusive of mobilising, immobilising and walking times.
DRI2 1.3.4