ASTM D7794 Standard Practice for Blending Mid-Level Ethanol Fuel Blends for Flexible-Fuel Vehicles with Automotive Spark-Ignition Engines
1. Scope
1.1 This practice applies to the blending of automotive spark-ignition engine fuels with ethanol concentrations greater than those suitable for conventional-fuel vehicles and less than the minimum ethanol content specification limits of Specification D5798. These mid-level ethanol fuel blends are for use in flexible-fuel vehicles and are sometimes referred to at retail as "Ethanol Flex Fuel".

1.2 These mid-level ethanol fuel blends are only suitable for use in ground flexible-fuel vehicles equipped with spark-ignition engines. Flexible-fuel vehicles are designed to operate on gasoline or gasoline-ethanol blends that meet the requirements of Specification D4814, ethanol fuel blends that meet the requirements of Specification D5798, or any combination of these. In the United States, these vehicles are certified by the U.S. EPA as emissions compliant with these types of fuels.

1.3 The mid-level ethanol fuel blend shall be blended from either:
1.3.1 Denatured fuel ethanol conforming to the requirements of Specification D4806 with a reduced limit on inorganic chloride content that will ensure no more than 1 mg/kg inorganic chloride in the finished fuel and from spark-ignition engine fuel conforming to Specification D4814 (often at a distribution terminal or bulk plant), or

1.3.2 Ethanol fuel blends conforming to Specification D5798 and from spark-ignition engine fuel conforming to Specification D4814 (often at a retail site).

1.4 This practice describes the required procedures for blending various mid-level ethanol fuel blends for flexible-fuel vehicles at the bulk distribution point or retail/commercial delivery site. These requirements may be applied at other points in the production and distribution system when provided by agreement between the purchaser and the supplier.

1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

2. Referenced Documents
2.1 ASTM Standards:
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
D4175 Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
D4177 Practice for Automatic Sampling of Petroleum and Petroleum Products
D4806 Specification for Denatured Fuel Ethanol for Blending with Gasolines for Use as Automotive Spark-Ignition Engine Fuel
D4814 Specification for Automotive Spark-Ignition Engine Fuel
D4815 Test Method for Determination of MTBE, ETBE, TAME, DIPE, tertiary-Amyl Alcohol and C1 to C4 Alcohols in Gasoline by Gas Chromatography
D5191 Test Method for Vapor Pressure of Petroleum Products (Mini Method)
D5501 Test Method for Determination of Ethanol and Methanol Content in Fuels Containing Greater than 20% Ethanol by Gas Chromatography
D5599 Test Method for Determination of Oxygenates in Gasoline by Gas Chromatography and Oxygen Selective Flame Ionization Detection
D5798 Specification for Ethanol Fuel Blends for Flexible-Fuel Automotive Spark-Ignition Engines
D5842 Practice for Sampling and Handling of Fuels for Volatility Measurement
D5854 Practice for Mixing and Handling of Liquid Samples of Petroleum and Petroleum Products
D6469 Guide for Microbial Contamination in Fuels and Fuel Systems
D7319 Test Method for Determination of Existent and Potential Sulfate and Inorganic Chloride in Fuel Ethanol and Butanol by Direct Injection Suppressed Ion Chromatography
D7328 Test Method for Determination of Existent and Potential Inorganic Sulfate and Total Inorganic Chloride in Fuel Ethanol by Ion Chromatography Using Aqueous Sample Injection
D7923 Test Method for Water in Ethanol and Hydrocarbon Blends by Karl Fischer Titration

2.2 Other Standards:
16 CFR United States Code of Federal Regulations, Title 16, Part 306
40 CFR United States Code of Federal Regulations, Title 40, Part 86

3. Terminology
3.1 For general terminology, refer to Terminology D4175.

3.2 Definitions:
3.2.1 automotive fuel rating, n - the automotive fuel rating required under the amended Octane Certification and Posting Rule (or as amended, the Fuel Rating Rule), 16 CFR, Part 306.
3.2.1.1 Discussion - Under this Rule, sellers of liquid automotive fuels, including alternative fuels, must determine, certify, and post an appropriate automotive fuel rating. The automotive fuel rating for gasoline is the antiknock index (octane rating). The automotive fuel rating for alternative liquid fuels consists of the common name of the fuel along with a disclosure of the amount, expressed as a minimum percentage by volume, of the principal component of the fuel. For alternative liquid automotive fuels, a disclosure of other components, expressed as a minimum percentage by volume, may be included, if desired. This is applicable in the United States.

3.2.2 conventional-fuel vehicle, n - a vehicle designed to operate on spark-ignition engine fuel that complies with Specification D4814.

3.2.3 denatured fuel ethanol, n - fuel ethanol made unfit for beverage use by the addition of denaturants under formula(s) approved by the applicable regulatory agency to prevent the imposition of beverage alcohol tax.

3.2.4 ethanol, n - ethyl alcohol, the chemical compound C2H5OH.

3.2.5 ethanol fuel blend, n - a high concentration ethanol-based fuel for flexible-fuel spark-ignition engines and vehicles.

3.2.6 flexible-fuel vehicle, n - a vehicle designed to operate on either unleaded gasoline or ethanol fuel blends or mixtures of both.
3.2.6.1 Discussion - In the United States, these vehicles have U.S. EPA emissions certifications using gasoline complying with U.S. EPA requirements and ethanol fuel blends that meet the requirements of Specification D5798.

3.2.7 fuel blending dispenser, n - a device for measuring and dispensing fuel, conforming to the standards established by the applicable regulatory jurisdictions, that can volumetrically combine two different base products into newly formed blended products that may be dispensed through a single hose or multiple hose dispenser configuration.

3.2.8 fuel ethanol, n - a grade of undenatured ethanol with other components common to its production (including water) that do not affect the use of the product as a component for automotive spark-ignition engine fuels.

3.2.9 gasoline, n - a volatile mixture of liquid hydrocarbons, generally containing small amounts of additives, suitable for use as a fuel in spark-ignition, internal combustion engines.

3.2.10 gasoline-ethanol blend, n - a fuel consisting primarily of gasoline along with a substantial amount (more than 0.35 mass % oxygen) of ethanol.

3.2.11 mid-level ethanol fuel blend, n - an automotive spark-ignition engine fuel with an ethanol concentration greater than those suitable for conventional-fuel vehicles and less than the minimum ethanol content limit of Specification D5798.
3.2.11.1 Discussion - Mid-level ethanol fuel blends are often referred to as EXX, where XX represents the nominal percentage of denatured fuel ethanol.