Analysis of Barrier Performance on HOPE Fuel Tanks Using a Mini-SHED Test Procedure

A test facility has been designed and constructed by Air Products and Chemicals Inc. for evaluating the barrier properties of plastic automotive fuel tanks. A procedure for evaluating the hydrocarbon emissions from fuel tanks during the EPA Diurnal Breathing Loss Test has been proposed. This emissions level is then characterized in terms of its contribution to the permissible level for total hydrocarbon emissions. In-situ fluorinated high density polyethylene (HDPE) tanks, post-fabrication sulfonated HDPE tanks and untreated HDPE tanks were tested, and it was shown that both treatment methods reduced emission levels for hydrocarbon fuel by a factor of thirty. Isothermal emission tests confirmed the improvement in barrier properties resulting from these treatments.