Fixed CO2 decision with a crew member unaccounted for in the purifier flat
At 02:40 the fire detection panel on a 1,200 TEU feeder ship alarms for the purifier-room smoke detector. The same alarm has been silenced twice in the previous week because of steam from a purifier, and the duty engineer silences it again and sends the oiler to check. Three minutes later the oiler reports by sound-powered telephone: fire at the sludge tank, heavy smoke, he cannot get out of the flat. There is no further transmission. The purifier-room fire damper is open and the supply fan is still running. Muster shows 17 of 18 crew; the oiler is missing. The chief engineer calls the bridge for permission to release the fixed CO2 into the purifier flat immediately. The CO2 room key is in the master's cabin and the master is on the bridge. The paint locker is on the same flat, separated by a steel bulkhead.
1. Set out the actions in the first five minutes, in order, and explain the purpose of each.
Read the worked answer
- Sound the general and engine-room alarm and announce the location; muster at the fire station and take a head count by name. Purpose: everyone knows what and where, and the missing person is identified early.
- Inform the bridge. The master takes charge; the OOW adjusts course so smoke is carried clear of the accommodation and the funnel uptake.
- Stop the machinery serving the flat (purifier, fuel-oil and lube-oil pumps) and trip the supply and exhaust fans and close the fire damper. Purpose: starves the fire of air and, more urgently, stops smoke and flame being pushed into the accommodation and up the casing.
- De-energise the flat, keeping emergency lighting and the emergency fire pump.
- Close every opening to the space: doors, skylights, casing accesses, sounding arrangements.
- Boundary cool the deck and bulkheads of the flat and the paint locker with water spray, keeping clear of live electrical panels.
- Send two teams in BA, briefed, with a charged hose, under an entry control officer, to search for the oiler and attack the fire; a rescue team and a second hose stand by.
- Line up the fixed CO2 but do not release it until the search result is known.
2. Should the CO2 be released now? Give your reasoning, the conditions that must be met, and the circumstances that would change your answer.
Read the worked answer
Not yet. Releasing CO2 into a space where a person may be is a decision to be justified, not a reflex:
- The design concentration in a machinery space, 30-40 percent, is immediately dangerous to life. A person inside has no realistic chance, and gas leaking through openings can reach adjoining spaces, which is why everyone must be accounted for and openings sealed.
- The system requires the space sealed, ventilation stopped, a pre-discharge alarm sounded to warn everyone, two separate release controls operated, and release in a single operation, made under the master's authority in the SMS. None of those conditions is fully met while 17 of 18 are mustered.
- The fire is currently contained: supplies stopped, fans stopped, boundary cooling in progress, paint locker protected.
Decision: use the next 5-10 minutes for a rapid, methodical BA search of the flat, two teams, hard line, thermal imager, with CO2 held on the master's order. Reassess on the result.
Release immediately if: the search confirms nobody is inside, the fire is breaching the boundary towards the accommodation, or the space is untenable and the search is complete. On release, all personnel out of the space and off the deck above, alarm sounded, the space left sealed and not reopened until cooled. Log the time and reason.
3. What do the silenced alarm and the failed telephone call tell you, and what should change?
Read the worked answer
The silenced alarm. Silencing a repeated nuisance alarm twice in a week conditions the whole crew to disregard it. The third event was real, and three minutes were lost. A silenced alarm is a suppressed alarm. Every silencing must be logged with a reason and an investigation, and a detector that keeps alarming in an unmanned machinery space at night should be treated as a defect to be fixed, not a nuisance.
The communication. The oiler was sent alone, reported on a sound-powered telephone, and the circuit went dead with him at the fire - there is no recording and no way to locate the handset. Sending an untrained person alone as first responder to an alarm is the underlying failure.
Changes:
- Treat every alarm as real until a person at the scene confirms otherwise; send two, with a portable radio.
- Portable UHF/VHF sets on charge at designated stations with spare batteries; test PA, telephone and radios as part of the weekly drill.
- Repair the interlock so the detector signal stops the fan and closes the damper; test the damper, not just the detector.
- Muster by name, and require the report to include each missing person's last known location and time.