In a full NFPA 2001 discharge, which sequence is correct?

• A. Detection triggers release, design concentration is reached, alarms activate, hold time observed, then system is cleared
• B. Detection triggers alarms, release activates, design concentration is reached, hold time observed, then system is cleared
• C. Detection triggers release, alarms activate, design concentration is reached, hold time is observed, then system is cleared
• D. Alarms activate, hold time observed, design concentration is reached, detection triggers release, then system is cleared

Answer: (C)

In a full NFPA 2001 discharge, the events unfold in a specific order to ensure rapid extinguishment while alerting occupants and then restoring safe conditions. Detection triggers release, so the releasing devices activate as soon as the system detects a fire. As soon as the release command is issued, alarms activate to warn occupants. The agent concentration then rises and reaches the design concentration needed for effective extinguishment. Once that design concentration is achieved, the hold time begins, maintaining the concentration for the required duration to ensure the fire is suppressed. After the hold time elapses, the system is cleared and normal ventilation or purge procedures restore safe air levels. This sequence captures the intended flow: detection leads to release, alarms alert, design concentration is reached, hold time is observed, then the system is cleared.