ASTM D7794-21

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Designation: D7794 − 20 D7794 − 21
Standard Practice for
Blending Mid-Level Ethanol Fuel Blends for Flexible-Fuel
Vehicles with Automotive Spark-Ignition Engines
This standard is issued under the fixed designation D7794; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
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.
This practice is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcommittee
D02.A0.02 on Oxygenated Fuels and Components.
Current edition approved July 1, 2020April 1, 2021. Published July 2020April 2021. Originally approved in 2012. Last previous edition approved in 20182020 as
D7794 – 18a.D7794 – 20. DOI: 10.1520/D7794-20.10.1520/D7794-21.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7794 − 21
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 C to C Alcohols in
1 4
Gasoline by Gas Chromatography
D5191 Test Method for Vapor Pressure of Petroleum Products and Liquid Fuels (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
D7794 Practice for Blending Mid-Level Ethanol Fuel Blends for Flexible-Fuel Vehicles with Automotive Spark-Ignition
Engines
D7923 Test Method for Water in Ethanol and Hydrocarbon Blends by Karl Fischer Titration
2.2 Other Standards:Government Regulations:
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.
3.2.1 conventional-fuel vehicle, n—a vehicle designed to operate on spark-ignition engine fuel that complies with Specification
D4814. D5798
3.2.2 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. D4806
3.2.3 ethanol, n—ethyl alcohol, the chemical compound CH CH OH. D4806
3 2
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cfr.
D7794 − 21
3.2.4 ethanol fuel blend, n—an automotive spark-ignition engine fuel composed of hydrocarbon and ethanol blendstocks for
flexible-fuel vehicles with ethanol concentrations greater than those used for conventional-fuel vehicles. D5798
3.2.4.1 Discussion—
Ethanol fuel blends are often referred to as Ethanol Flex Fuel or EXX, where XX represents the nominal percentage by volume
of denatured fuel ethanol in the finished fuel. D5798
3.2.5 flexible-fuel vehicle, n—a vehicle designed to operate on both gasoline and ethanol fuel blends and can operate on any
mixture of both.
3.2.5.1 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.
3.2.5.2 Discussion—
Flex-fuel vehicle and FFV are commonly used synonyms for flexible-fuel vehicle.
3.2.5.3 Discussion—
The fuels may also contain anti-oxidants, corrosion inhibitors, metal deactivators, and dyes but do not contain lead additives. A
jurisdiction may set limits on lead content from all sources D5798
3.2.6 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.
3.2.7 fuel ethanol, n—a grade of 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. D4806
3.2.7.1 Discussion—
The common components do not include denaturant.
3.2.8 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. D4814
3.2.9 gasoline-ethanol blend, n—a fuel consisting primarily of gasoline along with a substantial amount (more than 0.35 0.35 %
by mass % oxygen) of ethanol. D4806
3.3 Definitions of Terms Specific to This Standard:
3.3.1 automotive fuel rating, n—in the United States, the automotive fuel rating required under the amended Automotive Fuel
Rating Certification and Posting Rule (or as amended, the Fuel Rating Rule), 16 CFR, Part 306.
3.3.1.1 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 octane rating (antiknock index). 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.
3.3.2 mid-level ethanol fuel blend, n—an automotive spark-ignition engine fuel made by blending a Specification D4814 fuel and
a Specification D5798 fuel according to Practice D7794.
3.3.2.1 Discussion—
Ethanol fuel blends are often referred to as Ethanol Flex Fuel or EXX, where XX represents the nominal percentage by volume
of ethanol in the finished fuel.
4. Summary of Practice
4.1 This practice provides procedures for blending automotive spark-ignition engine fuels with ethanol concentrations greater than
those suitable for conventional-fuel vehicles and less than the minimum ethanol content limit of Specification D5798. It addresses
in detail the various factors which need to be considered when blending. These considerations include selection of fuel components
for blending and general handling information.
D7794 − 21
5. General Requirements
5.1 The fuel blending components specified in this practice shall meet the performance requirements of Specifications D4814, and
either D5798 or D4806 and all applicable regulatory fuel requirements.
5.2 The blending party, being responsible for the finished product, shall be provided, at the time of delivery of the fuel, on product
transfer documents, an invoice, bill of lading, shipping paper, or other documentation, a declaration of the product type and grade
of the fuels that are the intended fuel blending components. It is recommended that the blending party conduct testing and
inspections to determine applicable properties that are necessary to ensure the blending of compliant mid-level ethanol fuel blends.
5.3 Product transfer documents alone may not be sufficient to demonstrate conformance. A Certificate of Analysis representative
of the fuel being delivered is recommended to ensure compliance.
5.4 The fuel blender or testing analyst, or both, is warned that some requirements and test methods applicable to automotive
spark-ignition engine fuels depend on whether the fuel is a gasoline, a gasoline-ethanol blend, or ethanol fuel blend. Once the
amount of ethanol is known for the gasoline or gasoline-ethanol blend component and for the Specification D5798 ethanol fuel
blend or Specification D4806 fuel ethanol component, the appropriate blending ratios can be determined for the blending of the
two components.
5.4.1 Test Method D5501 shall be used for determination of the volume percent ethanol for the fuel ethanol component (that is,
high concentration ethanol) and to verify the mid-level blend fuel, and Test Methods D4815 or D5599 shall be used for the gasoline
or gasoline-ethanol blend component (that is, low concentration ethanol).
5.5 In order to ensure the presence of no more than 1 mg/kg inorganic chloride in the finished fuel or in Specification D5798, the
ethanol component specified herein shall meet all the requirements of Specification D4806 with a more restrictive inorganic
chloride limit as determined in Test Methods D7319 and D7328. The hydrocarbon blending component specified herein shall meet
all the requirements of Specification D4814.
5.6 Mid-level ethanol fuel blends shall be visually free of water, sediment, and suspended matter. It shall be clear and bright at
the point and condition of custody transfer and display no indication of phase separation.
5.7 The finished fuel shall also be free of any adulterant or contaminant that could render the fuel unacceptable for its commonly
used applications.
6. Blending Procedures
6.1 This practice includes procedures for blending mid-level ethanol fuel blends at the bulk distribution terminal and at retail using
a fuel blending dispenser.
6.2 A fuel blending plan shall be developed describing the necessary actions needed to achieve the targeted mid-level ethanol fuel
blends and performance expectations of flexible-fuel vehicles.
6.2.1 Blending plans utilizing new equipment installation or conversion of existing equipment depend on thorough preparation and
planning for the entire fuel system.
6.2.2 The investigation and design of the wetted fuel system starts with a review of the flow of the fuel from receipt through retail
delivery ensuring materials compatibility with the blending components and the blended mid-level ethanol fuel blends.
6.2.3 Fuel storage and blending systems shall be approved by the jurisdictions in charge of storage tanks, fuel dispensers, and
associated equipment.
6.2.4 If a single hose blending dispenser is used, the entire dispenser shall be dedicated to serving flexible-fuel vehicles. If a
multiple hose dispenser configuration is used, one hose may be dedicated to E0 or E10 fuel, and one or more additional hoses may
be dedicated to mid-level ethanol fuel blends.
D7794 − 21
6.2.5 Documentation of the findings and changes made during the system review may prove beneficial for the fuel blender’s future
reference.
6.2.6 The plan should include a strategy for handling the variability in ethanol and gasoline content in fuels being delivered and
shall take into consideration the design and operational abilities of the blending meters that will be used.
6.2.7 This review should apply to the initial handling point at the terminal, through the distribution and transport system, and
ultimately to the end point—the retail point of sale.
6.3 Determination of Blending Component Properties:
6.3.1 It is the responsibility of the suppliers of fuels that will be used for blending mid-level ethanol fuel blends to provide the
blending parties with product transfer documents that contain, at a minimum, the information required by all applicable regulatory
agencies. In the United States, this includes, among other items, a product description and the applicable Automotive Fuel Rating.
The fuel supplier is responsible
...