The International Maritime Organization (IMO) has introduced requirements that are applicable retrospectively to oil fuel systems on board existing ships. The requirements, as detailed in IMO Resolution MSC.31 (63), are to be complied with by July 1, 2003. They may require modifications to diesel engine high pressure fuel delivery pipes, insulation of hot surfaces and screening of low pressure fuel pipes.

Existing single-walled fuel pipes between high pressure fuel pumps and injectors are to be jacketed i.e. fitted with an outer pipe capable of containing fuel from a high pressure pipe failure. This will normally mean replacement of single-walled pipes with the engine manufacturer’s approved double-walled pipe and installation of suitable oil collection and alarm arrangements. Engines with a power output of less than 375kW having fuel-injection pumps serving more than one injector, may be fitted with an enclosure to effectively contain any fuel leakage.

Low pressure fuel pipes are to be screened to avoid oil spray or leakage onto hot surfaces, into machinery air intakes, or other sources of ignition. All pipe connections close to such locations must be carefully considered and in some cases, particularly where a connection is directly above a hot surface, the pipe may need to be re-routed or the connection replaced by a butt welded joint.Surfaces with temperatures above 220 deg C, which may be impinged as a result of a leak from an oil system failure, are to be insulated. Where the insulation is oil absorbent, the insulation should be encased in steel sheathing.