What is the difference between automatic and manual release in NFPA 2001?

• A. Automatic release is initiated by a person at a pull station; manual release is triggered by detectors.
• B. Automatic release is triggered by detectors; manual release is initiated by a person at a pull station.
• C. Automatic release uses water-based agents; manual uses inert gas.
• D. Automatic release requires occupancy clearance; manual does not.

Answer: (B)

In NFPA 2001, the way the system initiates discharge is what sets automatic apart from manual. Automatic release is triggered by detectors that sense a fire condition and automatically release the clean agent without the need for a person to act. Manual release, on the other hand, is started by a person at a pull station or release device, giving human oversight or control over when the agent is discharged.

This distinction matters because automatic release provides rapid fire suppression as soon as the detectors indicate a fire, while manual release allows an operator to verify conditions, coordinate with evacuation, or intervene if automatic release isn’t desirable in a given situation. The other choices don’t fit: they either flip who initiates the release, suggest a difference in agent type (water-based versus inert gas) that isn’t what defines automatic vs manual in this context, or incorrectly tie automatic release to occupant clearance.