After what time can a dirty apparatus be cleaned by the next shift?

The correct choice indicates that a dirty apparatus can be cleaned by the next shift at 1500 hours. This time is significant because it allows an adequate window for the apparatus to be in service during the busy hours of the day, while also ensuring that cleaning operations do not interfere with emergency responses.

Cleaning at 1500 hours typically falls into a timeframe when shifts are preparing to transition, allowing for a practical and efficient schedule to ensure that apparatus are returned to a ready state. This routine is important for maintaining operational readiness and compliance with departmental standards, as a clean apparatus reflects professionalism and is safer for personnel to work with.

The other options represent times that may interfere with shift changes or operational demands. For instance, cleaning too early in the shift could also limit the availability of the apparatus for emergencies, whereas later times might not provide enough time for the cleaning to be effectively conducted before the end of the shift. Thus, 1500 hours strikes a balance between operational efficiency and maintenance.