16 CFR Part 306; Automotive Fuel Ratings, Certification and Posting; Project No. R811005
Fuel Rating Rule Review, 16 CFR Part 306, Project No. R811005 I am commenting on the use of ASTM D6122 to determine compliance with (R+M)/2 posting on gasoline dispensers. I am a consultant on fuels and fuel specifications and retired from an oil company with over 50 years experience. I have been a member of ASTM International for 38 years and I have been the chairperson of Section 1 of ASTM Subcommittee D02.A for 29 years. which is responsible for D4814 Specification for Automotive Spark-Ignition Engine Fuel. The FTC proposal states, "(3) Use a multivariate infrared spectrophotometer, as described in Section 6.1.1 of ASTM D6122--10, ''Standard Practice for Validation of the Performance of Multivariate Infrared Spectrophotometers,'' to determine the research octane number and the motor octane number following the procedures set forth in ASTM D6122--10 to correlate the measured research and motor octane numbers with the results of test methods ASTM D2699--09 and ASTM D2700--09 (incorporated by reference, see § 306.0(b)(2))." The title of D6122 indicates it is not a test method that provides any test results. It does not even mention octane number. It only covers "liquid petroleum products" in its scope which doesn't cover using it for gasoline-alcohol blends. An ASTM Practice "is an accepted procedure for the performance of one or more operations or functions." D6122 provides requirements for calculations of physical and chemical properties, not just octane number. It has no precision statement as is required of test methods. Section 6.1.1 doesn't provide much useful guidance. More procedural information than just approving the use of D6122 is required to determine octane numbers. While IR procedures have good repeatability and reproducibility, the result for an unknown sample relies on how well the correlation is with D2699/D2700 engine test results of a group of calibration fuels. The result may be biased if the correlation fuel set does not cover the composition of the unknown test fuel. The correlation that is developed by one laboratory is not necessarily applicable to another laboratory because the correlation depends upon the composition of the correlation fuel set. There is no universal correlation fuel set that can be used by all laboratories for all possible unknown samples. There currently is no approved ASTM test method that reports octane number using IR spectroscopic data. Before the FTC approves a non-engine test method for octane number determination for compliance, a standard ASTM test method covering products of interest in the scope in the octane number range of interest and with published precision needs to be approved. IR testing of fuels with compositions outside the correlation fuel set can result in incorrect results compared to D2699/D2700. This is why it is important to specify that the basic engine test methods D2699 and D2700 are the referee test methods in case of dispute. An example of the problem occurred in a major U.S. city a number of years ago when a newspaper hired a laboratory with an IR octane number instrument to test premium-grade gasolines. The instrument produced lower values than were posted on the dispensers. The newspaper wrote an article claiming that the gasoline marketers were cheating the public. When the gasolines in question were engine tested by D2699/D2700, they were found to be in compliance. It is my understanding that many state inspection laboratories are using an IR method to screen gasoline samples for further testing by D2699/D2700 those samples that appear low. Citations are issued based on the engine tests. With the approval of using only D6122 to determine compliance of field samples, the use of engine testing may end resulting in marketers being falsely cited for not meeting the dispenser posted value and having no official recourse. Another concern relates to referencing old versions of ASTM standards. The current ASTM versions used in the proposed rules are D4814-13b, D2699-13b and D2700-13b, D2885-13, and D6122-13. Changes are made to improve, update apparatus, expand the scope, update the precision statement, improve safety, and correct or clarify wording in a standard.