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The need to meet today's stringent environmental legislation requires that all fuel system components, including flexible rubber hoses, have exceptional permeation resistance to standard and oxygenated fuels. To help meet this need, new ultra low permeation laminates that retain the flexibility of rubber fuel hose have been developed. These laminates are made up of a fuel contact layer of fluoroelastomer (FKM), a permeation barrier of very thin (0.05 mm) fluorinated ethylene propylene (FEP) plastic film and a conventional elastomeric backing layer. Adhesion between the layers exceeds the tear strength of the elastomers. These laminates are useful for making fuel hose that exhibits outstanding permeation resistance while retaining the ease of coupling and the flexibility associated with standard rubber hose.

Environmental actions by the California Air Resources Board (CARB) may have a significant effect on emission requirements in the Small Off-Road Engine (SORE) segment. Meeting these new proposed standards will require material and design changes to engine seals, fuel hoses, and fuel tanks. New membrane filter technology is also being developed to manage diurnal emissions from fuel systems. This paper discusses what these options are in each of the critical application areas. Relative permeation rates of the various materials were determined by either a simple gravimetric cup method or a gas chromatographic technique that permits identification of the permeating species. Data from experiments of this type were shown to correlate well with results obtained on actual parts in the Sealed Housing Evaporative Determination Test (SHED).