How should post-discharge ventilation be handled?

• A. Ventilation may be controlled to purge the space and restore normal air conditions, with caution to avoid re-entrance hazards.
• B. Ventilation should be avoided entirely.
• C. Ventilation should run at full rate forever.
• D. Ventilation is irrelevant after discharge.

Answer: (A)

Post-discharge ventilation is used to purge the space of the extinguishing agent and restore normal air conditions, while also guarding against re-entrainment of contaminated air. After the agent is released, residual concentrations can linger and still pose inhalation hazards, so controlled ventilation helps remove those residues safely. It’s important to manage the rate and direction of airflow so you don’t inadvertently draw contaminated air back into the space or spread the agent to adjacent areas. Monitoring is used to determine when the air is safe for occupancy, and re-entry should occur only after conditions meet established safety criteria. This approach ensures that the space is cleared of the agent and safe for people to return, rather than leaving the space sealed or venting indefinitely.