Logical zones grouped by device function for D-304. Physical detection-zone boundaries (Clause 13) are defined on the as-designed drawing.
| Optical Smoke | 10 |
| CO Detector | 2 |
| Zone total | 12 |
| Manual Call Point | 2 |
| Zone total | 2 |
| Visual Alarm Device | 4 |
| Sounder | 4 |
| Zone total | 8 |