On August 18th 2014 an engine room fire aboard the Bahamian flagged 485ft chemical tanker not only disabled the vessel but killed a crew member out of the 22. The vessel remained without propulsion 700 miles west Cape Blanco. A ship’s engine room is home to a variety of machines with a single purpose which is to keep the ship afloat and moving as it houses propulsion systems; making this part more dangerous as it relates to fuel substances which have a chance of either combustion or any other dangerous consequence of under maintenance or careless operation.
The engine room/ER fires, according to DNV (Det Norske Veritas) start when minor details go wrong with 2/3 fires starting there along with a 63% chance of occurrence with most being controllable. The rest of fire-prone places are crew accomodations (10% chance) and cargo holds. (27%) The engine room fire is also able to spread to other areas of the ship and cause more damage with incidents such as “Romantica” passenger vessel in the Mediterranean where the fire aboard damaged the entire vessel. Another example of ER fire damage is “Sun Vista” cruise liner which sunk off the coast of Malaysia; showing that such accidents can determine the vessel’s fate. Finally, according to DNV’s statistics a shipowner operating 20 vessels should expect at least one major ER fire every 10 years; establishing ER fires as common in maritime and asking ship management to implement a clear policy on avoidance.
To begin our approach it is beneficial to breakdown the entire dimension from the ground up; analysing the nature and position of an ER and possible sparks for the fire. The ER is the largest physical compartment for machinery which houses the vessel’s prime mover, commonly a variation of a heat- diesel engine or a gas-steam turbine with some ships having more than one ER; present in port and starboard, forward and aft or simply numbered. However the most common position of an ER is near the bottom, rear, at the aft or the end of the vessel and usually comprising a few compartments. Some vessels, especially those built from 1900 to 1960 have the ER in the mid-ship area.
Engines, the namesake of the ER also breakdown into different categories; propulsion/main engines which turns the propeller and burns either diesel or heavy oil fuel and having the ability to switch between the two. Larger propulsion engines also drive electrical generators to supply the ship’s electrical equipment; larger vessels typically have 3+ synchronised generators to ensure smooth operation; produced the combined output which is above the power requirement of the vessel which accommodates maintenance or loss of one generator.
Steam-driven vessels are moved and powered by one or more large boilers, creating the alternative name “boiler room,” driving the engine with high-pressure steam and powering the vessel with turbo generators. A steam vessel, aside from propulsion and auxiliary engines also has smaller engines, generators, air compressors, feed pumps and fuel pumps. Finally, the conclusion on the possible nature of ERs and boiler rooms is that these are volatile places which have almost zero margin of error as all systems are connected and use potentially hazardous materials.
The nature of ER systems leads to the fact that fires start due to the smallest details going wrong and producing a chain reaction as a result which, if not properly addressed can sink the entire vessel. Since there are many systems to keep track of it is difficult to establish focus and anticipate fires along with finding experience data being hard on its own. However, according to DNV the ER fire incidents originate from:
- 9% electrical errors
- 7% hotwork
- 14% component failure
- 14% boiler incidents
- 56% oil leakage
After seeing the statistics above it is somewhat easier to establish the first tactic; an on-site survey. This tactic can identify possible errors in the machinery; faults, leakages, assessment of the fuel systems, active and passive fire protection. Theoretically, the counter-measures should start from removal of hot surfaces and correct installation of couplings and hosings at fuel oil-using systems; providing rapid response if a fire was to occur. Talking about hot surfaces, most fuel oils ignite upon hitting a surface whose temperature is above 250 degrees; requiring shielding or insulation of surfaces above 220. However the challenge here is detecting what surfaces are hot and thus dangerous which is impossible to do with the naked eye; therefore requiring knowledge of zones which get hotter.
Areas to consider in a Diesel Engine; (!) marking common trouble areas
- Engine body
- Indicator valves (!)
- Cylinder hoods
- Exhaust pipes from all cylinders (!)
- Tie-in to exhaust manifold
- Exhaust manifold overlapping between steel sheets and laggings (!)
- Turbochargers and flanges to them (!)
- Cut-outs for pressure/ temperature sensors (!)
- Surfaces of floodlights
Any of the above areas can start a fire in the ER if fuel leaks, requiring to know about known leakage zones which are randomly distributed between flexible hoses, couplings, clogged filters and fractured pipes. Parts such as flexible hoses should only be installed where necessary to absorb vibrations; avoiding sharp bends.
ERs are places of high temperature and pressure which directly affects crew working there as such factors are known to impact health and productivity; serving as a second factor for accident. Pressure can create one of the most dangerous accidents in ER; boiler explosion. This type of accident is caused by either overheating or lack of purging. Overheating also is a factor which is caused by loss of water circulation.
Another accident associating with pressure is the highly-pressurised air compressor equipment; occurring during maintenance when the discharge air valve is closed to minimise air leakage. Explosion occurs when the valve is not opened again while starting the compressor while relief valves fail to operate.
So far, it can be seen that to address dangerous accidents is to predict and avert them; done by knowing in advance the possible zones which need to be addressed with proper maintenance. However, in order to do a proper inspection of possible accident zones one needs proper instruments. There are 3 essential instruments; surface/ contact thermometer, laser-based infrared heat tracers and infrared thermo-scanning video equipment.
Contact thermometers are less dependent on calibration and will measure directly onto the surface without the need to estimate the emissivity factor. Laser-based infrared tracers will measure average local temperature; dependent on the distance from the tracer. Infrared thermo-scanning video equipment is used for tracing the source of the high temperature.