User:Ezelezel/Jacketed fuel Injection Pipes

Jacketed fuel injection pipes (Also known as double walled, twin walled or sheathed fuel injection pipes) are a special type of fuel injection pipe fitted to diesel engines.

The pipes incorporate an outer jacket that shrouds the inner high pressure pipe. This jacket is usually metallic in construction and can either be a thin walled tube or convoluted hose. In the event of a burst in the injection pipe the leaking fuel will be collected by the jacket and piped away safely.

Jacket fuel lines are found predominately in marine applications where they can be required by law, although adoption in power generation is becoming more common.

Legislation
IMO Resolutions MSC.31(63) (adopted on 23 May 1994) required that all ships over 500 GT be fitted with jacketed fuel lines. Existing vessels and new builds constructed before 1998 were required to comply by 1st July 2003.

Dispensation was given to engines smaller than 375 kW (500 hp) providing they were fitted in a suitable enclosure.

Controversy
The fact that resolution MSC.31(63) required existing ships to be retrofitted by July 2003 was a major cause of concern for many operators of older vessels. The retrospective introduction of this regulation was difficult and expensive to implement for many legacy engines as no provision had been made for sheathed fuel pipes during the engines design.

A few specialist companies existed that could provide retrofit options, but these tended to be an expensive option for equipment that was nearing the end of its service life.

Under increasing pressure, the IMO finally relented and issued resolution MSC.201(81) (adopted on 18 May 2006) which relaxed the regulation so as to apply to ships constructed on or after 1 February 1992