Distillate Fuel Trends: International Supply Variations and Alternate Fuel Properties

The U.S. Army uses two fuels in the majority of its vehicles, aircraft, and support equipment. They are diesel fuel and jet fuel. These two fuels, and the specifications that govern them around the world, have undergone significant changes over the past two decades. There is a general trend toward a more uniform diesel around the world but the use of alternative fuels, such as biodiesel, has introduced additional variations in the world market. Aviation fuel, by comparison, is moving from a fairly narrowly defined, semi-formal set of standards to a formal international requirement. This report contains a discussion of the recent changes, as well as possible future changes, in the specifications and composition of these two important fuels. In addition to a comparison of specifications and composition, a series of inspection tests was performed on selected alternate diesel and jet fuels. Although there were some failures to meet specification limits, it was remarkable how often an alternate fuel that was clearly not suitable for routine use, passed the conformance testing. This work demonstrated that conformance to a specification is often insufficient as proof of fit for purpose conformance.