| Status of the door of lobby | Status of pressure differential (ΔP) between the accommodation and the lobby | Operating condition of leakage air flow blade | Operating condition of supplementary air flow blade |
| Closed | ΔP is higher than ΔP1 | · Opened in case ΔP is higher than ΔP1 · PID-controlled to maintain ΔP to be ΔP2 | Closed in case ΔP is higher than ΔP1 |
| Opened | ΔP is lower than ΔP1 | · Closed in case ΔP is lower than ΔP1 | Completely opened in case ΔP is lower than ΔP1 |