ClassDirect Live (Lloyd’s Register) has published a warning that leakage from the main and auxiliary diesel engines’ fuel systems has resulted in a number of recent machinery space fires. The causes have been identified as loosening of threaded plugs in engine fuel delivery systems, resulting in a spray of fuel igniting on contact with the exhaust manifold or turbocharger casing. Any leakage of fuel is a potential fire hazard and crew should inspect fuel systems on a regular basis. Particular attention should be given to the tightness of connections and more specific checks depending on the type of any plugs fitted.

Lloyd’s Register’s experience to date indicates that particular care needs to be taken with two types of plugs:
1. ‘Erosion’ plugs on fuel injection pump bodies, which protect the inner surface of the fuel injection pump body from erosion damage caused by the impact of fuel jets during operation. Because of erosion, these plugs have to be replaced at set intervals, determined by the engine builder, e.g. 16,000 running hours. Engine builders’ instructions for these should be strictly followed. Particular attention must be paid to the tightening torque and securing by the fitting of locking wire or equivalent device.

2. Plugs in ’low’ pressure fuel pipe lines from the booster pump, which are fitted for a variety of reasons, e.g. for bleeding purposes. It is important that proper care is taken when fitting these plugs and they should be secured by fitting a locking device.