Oil mist detector is fitted in 1C engine to alarm engine room personnel of initiation of oil mist formation inside the engine crankcase. If ignored, the oil mist can turn into a deadly explosion.
When the oil mist alarm sounds, following procedure has to be followed:
For UMS operation, the engine will give OMD alarm and after 10 sec delay, the engine will automatically slowdown For manned engine, inform the bridge about the alarm and slow down the main engine Stop the engine after consulting with bridge as soon as it is safe to stop Keep the lube oil pump running Some makers recommends to leave the engine room for at least 20 minutes after the OMD alarms sounds and engine is in stop mode Shut all the engine room doors and skylight to avoid flow of sudden excess of air to crankcase Once back in the engine room, engage turning gear and start rotating the engine Prepare to open the crankcase after engine is cooled down Check for any hotspots in the crankcase If hotspot is not found, check in cam case, chain or gear case as the alarm indicated in the OMD may not be accurate because oil mist circulates throughout the crank case Start the engine only when the cause of mist is identified and rectified
References
A Pocket Guide To Fixed Fire Fighting Systems and Emergency Procedures For Ship’s Engine Room (Author: Marine Insight)