A high speed car ferry with passengers onboard was on its way to port when a fire was detected in the port auxiliary engine room (picture 1). The fire was effectively extinguished by the ship's water fog system within 5-10 minutes. Extent of damage

Even though the fire was quickly extinguished, the heat was intense resulting in:

• Damaged instrumentation cabling on the engine.
• Damaged control cabling to/from engine panel and alarm panels.
• Destroyed air intake filters on the turbo charger.
• Light fittings, smoke detector head, telegraph, alarm sounder, junction boxes, and most electrical cabling in trays running close to the deck head were all heat damaged. The insulation around some cables melted, exposing conductors.
• The aft two fire dampers were immobilised in the closed position.
• The inboard side fuel-rail section upper joining pipe was detached from its correct location.
  

Probable cause
On this type of engine the fuel rails are split fwd/aft and are joined by short coiled lengths of single walled low pressure pipes (picture 2 and 3). These pipes are retained by composite rubber olives with steel inserts, which are designed to be renewable (picture 4). In this case, one of the pipes was blown out, thus releasing two jets of fuel directed at the turbocharger. The pipe that came out appeared to have been fitted and refitted a number of times. Being relatively thin walled, the pipe was probably crushed to a smaller diameter than the original.

Lessons to be learned

• Low pressure fuel pipes like the coiled pipes used on this engine should always be shielded, so that any possible oil spray from a leakage is kept away from the engines hot spots and the turbocharger. The screening is required even if all hot surfaces in the vicinity are insulated, and is always to be as good as if the surfaces were not insulated. The requirement for screening is emphasised in the retroactive SOLAS requirements II-1/15.2.10 (Consolidated Edition 2001).
  
• Proper insulation of an engine's hot spots should always be given high attention. All surfaces with a temperature above 220*C should be insulated, even if the fuel pipes in the vicinity have been screened. This is also emphasised in the retroactive SOLAS requirements II-1/15.2.9 (Consolidated Edition 2001).
  
• The re-use of fuel pipes in the engine's fuel injection system must always be in accordance with the engine's instruction manual and the guidelines from the engine manufacturer. It is also important to ensure that the components are not damaged or deformed in any way before refitting.

For more information contact:
Helge.Johannessen@dnv.com