A fixed CO2 system on a MODU with a capacity of over 300 lbs (136 kilograms) CO2 which protects spaces other than tanks must have __________.

Correct Answer: Option D — an audible alarm and time delay

Under 46 CFR 108.439, fixed CO2 systems carrying more than 300 pounds of agent and protecting spaces other than tanks require an audible pre-discharge alarm coupled with a pneumatic or electrical time delay device. This safeguards personnel in occupied spaces by giving mandatory warning time prior to gas discharge.