Common materials for modern fuel filter elements are synthetic fibres and/or cellulose. Micro glass fibres can also be used but because of the risk of migration of small glass fibre pieces broken off from the main element into critical fuel system components, their use in some applications is avoided [Petiteaux 2009]. In the past, pleated paper, packed cotton thread, wood chips, a mixture of packed cotton thread and wood fibres and wound cotton have also been used [Brady 1996].

The degree of filtration required depends on the specific application. In general, when two filters are used in series, the primary filter retains particles down to about 10 - 30 µm, while the secondary filter is capable of retaining particles greater than 2-10 µm. As fuel systems evolve, clearances and stresses on high pressure components increase and the need for clean fuel becomes event more critical. Both the capability of fuel filters to keep up with demands for cleaner fuel [Salvador 2009] as well as methods quantifying acceptable fuel contamination levels have needed to evolve [van Stockhausen 2009].