Before releasing the CO2 into the space, the alarm for a fixed CO2 system must sound for at least __________.

Correct Answer: Option A — 20 seconds

Title 46 CFR 108.439 mandates that the pre-discharge alarm for a fixed CO2 fire extinguishing system must sound automatically for at least 20 seconds before the carbon dioxide enters the space. This critical delay permits personnel to safely evacuate the compartment prior to oxygen depletion and toxic atmosphere concentration.