An alarm goes off and with it being a "single zone" how do you know which apartment (unless they are individually labelled on the panel)?

Based on the information provided—an addressable fire alarm system with apartments and a single zone—it appears that the panel display identifies the specific apartment or area where the alarm has been activated. If this is the case, multiple zones may not be necessary, as the panel effectively assigns a virtual zone to each apartment or designated area.

The key question then becomes: "How do the fire service personnel identify the exact location of the activation in relation to their current position at the fire panel?"

To address this, a diagram should be provided that clearly indicates the layout of the premises and the location of named areas as they appear on the fire panel display.

However, if the system only provides a general "activation in zone" light rather than specifying an exact location, then the zoning arrangement may be incorrect and require reassessment.

It is possible that the Fire Risk Assessor (FRA) is not requesting a traditional zone map, but rather a navigation aid to help responders unfamiliar with the building quickly locate the activated detector and determine the best route to access it.

Hope it helps.