Engine Room Fire and Fixed CO2
At 0230, 12 nm offshore, a 130-ft steel vessel is underway at 9 kts. Smoke is coming from the engine-room vents; a crew member reports flames near the port main. You have six persons aboard; the oiler is unaccounted for. The engine room has a fixed CO2 system with a manual pull station outside the space. The fire is growing. Wind is 15 kts. You have VHF and an EPIRB. The engine room is the only space protected by the CO2 system; the paint locker is adjacent but not protected. No one has yet shut down the fuel or ventilation.
1. What must be done before releasing CO2, and what is the controlling constraint?
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Muster the crew and take a head count. Stop the engines, close the fuel quick-closing valve, shut down ventilation, and close all openings to the engine room. Start boundary cooling and prepare to seal the space. The controlling constraint is that CO2 is lethal: never release it while anyone may be inside. All persons must be accounted for before the pull station is operated.
2. If the missing oiler cannot be found, how do you decide whether to release?
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Do not assume the oiler is outside the space. Conduct a rapid search with SCBA and a thermal imager if it is safe to do so. If the fire prevents search, treat the space as occupied and do not release CO2. Protect the rest of the crew, prepare to abandon or request assistance, and continue boundary cooling. Releasing CO2 with a person inside knowingly converts a fire emergency into a fatality. Release only after all persons are accounted for and the space is sealed.
3. After release, what indicates the fire is out, and what do you do next?
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Look for falling boundary temperatures, no smoke from seams or vents, and no re-ignition after a waiting period. Do not open the space immediately; admitted air can cause reflash. Keep the space sealed, continue boundary cooling, and maintain a reflash watch. When cooled, ventilate under SCBA control, test the atmosphere, and only then enter with fire teams.