The test method for acidity currently referenced in D5798 is D1613. D1613 isunder the jurisdiction of Committee D01 and was developed for solvent related products and does not include ethanol/hydrocarbon blends in its scope. There have also been concerns that the method, as written, does not consider the possible interferences encountered in the fuels and fuel components under SubcommitteeD02.A jurisdiction. This ballot will add an acidity method developed by and under the jurisdiction of Committee D02. Subcommittee D02.6 has members familiar with the ethanol/hydrocarbon blends covered by D5798 and the needs of a test method to address the acidity characteristics of this fuel. There has been concern for some time that dissolved carbon dioxide will interfere with the current acidity method specified in D5798. The acidity method is intended to determine the concentration of organic acids in ethanol. However, carbon dioxide is very soluble in ethanol, and in the presence of water it converts to carbonic acid. The current method, D1613, adds water to the sample and the mixture is titrated with a sodium hydroxide solution. Dissolved CO2, converted to carbonic acid while running the method, will be titrated as acid. The presence of dissolved CO2 will thus create a high bias in the results. If there is sufficient dissolved CO2, Test Method D1613 can incorrectly indicate the sample is above the maximum allowed acidity in the specification.This could lead to on-test product being declared off-test in the distribution system, which, in turn, could adversely impact product availability.In view of the shortcomings of D1613, and the excellent initial experience with DXXXX, members of the Task Force expect to eventually ballot for withdrawal of D1613, leaving only DXXXX as the test method for acidity in D5798. The Subcommittee D02.A Test Method Task Force asked Subcommittee D02.06 to develop a test method for acidity in the fuels and fuel components under the jurisdiction of Subcommittee D02.A. The method development was begun in 2009 as work item # 24458. As the method was being developed data were presented to Subcommittee D02.06 to verify that removing the dissolved CO2 did not impact the organic acid content of a sample. The Subcommittee D02.06 ballot to approve this method passed in the fall of 2011. This concurrent Committee D02/Subcommittee D02.A ballot is to incorporate the new test method into D5798. The ASTM document number will be incorporated when it is assigned by ASTM staff. There has been a desire by many parties to expedite the addition of this method to D5798. This ballot is running simultaneous with and is linked to the D02 main committee ballot for the test method. If the test method fails to pass the main committee ballot, this ballot will also fail.
acidity; alcohol; automotive spark-ignition engine fuel; chloride; copper corrosion; E85; ether; ethanol fuel blends for flexible-fuel automotive spark-ignition engines; flexible-fuel; hydrocarbon; inorganic chloride; lead; MTBE; oxidation stability; oxygenates; pHe; phosphorus; solvent washed gum content; sulfur; vapor pressure; volatility; water: Automotive engine fuels/oils--specifications; Ethanol; Fuel ethanol (Ed70-Ed85); Petroleum products--specifications;
Citing ASTM Standards
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