ASTM D5798-21

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D5798 − 20 D5798 − 21
Standard Specification for
Ethanol Fuel Blends for Flexible-Fuel Automotive Spark-
Ignition Engines
This standard is issued under the fixed designation D5798; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope*
1.1 This specification covers the requirements for automotive fuel blends of ethanol and gasoline for use in ground vehicles
equipped with ethanol fuel blend flexible-fuel spark-ignition engines. Fuel produced to this specification contains 51 % to 83 %
by volume ethanol. This fuel is for use in flexible-fuel vehicles and is sometimes referred to at retail as “Ethanol Flex-Fuel.”
Appendix X1 discusses the significance of the properties specified.
1.2 The vapor pressure of ethanol fuel blends is varied for seasonal climatic changes. Vapor pressure is increased at lower
temperatures to ensure adequate flexible-fuel vehicle operability. Ethanol content and selection of hydrocarbon blendstock are
adjusted by the blender to meet these vapor pressure requirements.
1.3 This specification formerly covered Fuel Ethanol (Ed70-Ed85) for Automotive Spark-Ignition Engines, also known
commercially as E85. The nomenclature “fuel ethanol” has been changed to “ethanol fuel blends” to distinguish this product from
denatured fuel ethanol Specification D4806. To facilitate blending of ethanol fuel blends that meet seasonal vapor pressure
requirements, a new lower minimum ethanol content has been established.
1.4 The United States government has established various programs for alternative fuels. Many of the definitions of alternative
fuel used by these programs may be more restrictive than the requirements of this specification. See 4.1.2.1 for additional
information on alternative fuels containing ethanol.
1.5 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for
information only and are not considered standard.
1.6 The following safety hazard caveat pertains only to the test method portion, 8.1.8, of this specification. 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 specification is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is under the direct responsibility of
Subcommittee D02.A0.02 on Oxygenated Fuels and Components.
Current edition approved May 1, 2020Oct. 1, 2021. Published May 2020October 2021. Originally approved in 1996. Last previous edition approved in 20192020 as
D5798 – 19b.D5798 – 20. DOI: 10.1520/D5798-20.10.1520/D5798-21.
*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
D5798 − 21
2. Referenced Documents
2.1 ASTM Standards:
D86 Test Method for Distillation of Petroleum Products and Liquid Fuels at Atmospheric Pressure
D130 Test Method for Corrosiveness to Copper from Petroleum Products by Copper Strip Test
D381 Test Method for Gum Content in Fuels by Jet Evaporation
D525 Test Method for Oxidation Stability of Gasoline (Induction Period Method)
D1613 Test Method for Acidity in Volatile Solvents and Chemical Intermediates Used in Paint, Varnish, Lacquer, and Related
Products
D1688 Test Methods for Copper in Water
D3231 Test Method for Phosphorus in Gasoline
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
D4306 Practice for Aviation Fuel Sample Containers for Tests Affected by Trace Contamination
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
D4953 Test Method for Vapor Pressure of Gasoline and Gasoline-Oxygenate Blends (Dry Method)
D5191 Test Method for Vapor Pressure of Petroleum Products and Liquid Fuels (Mini Method)
D5453 Test Method for Determination of Total Sulfur in Light Hydrocarbons, Spark Ignition Engine Fuel, Diesel Engine Fuel,
and Engine Oil by Ultraviolet Fluorescence
D5501 Test Method for Determination of Ethanol and Methanol Content in Fuels Containing Greater than 20 % Ethanol by Gas
Chromatography
D5854 Practice for Mixing and Handling of Liquid Samples of Petroleum and Petroleum Products
D6423 Test Method for Determination of pHe of Denatured Fuel Ethanol and Ethanol Fuel Blends
D7039 Test Method for Sulfur in Gasoline, Diesel Fuel, Jet Fuel, Kerosine, Biodiesel, Biodiesel Blends, and Gasoline-Ethanol
Blends by Monochromatic Wavelength Dispersive X-ray Fluorescence Spectrometry
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
D7667 Test Method for Determination of Corrosiveness to Silver by Automotive Spark-Ignition Engine Fuel—Thin Silver Strip
Method
D7671 Test Method for Corrosiveness to Silver by Automotive Spark–Ignition Engine Fuel–Silver Strip Method
D7757 Test Method for Silicon in Gasoline and Related Products by Monochromatic Wavelength Dispersive X-ray Fluorescence
Spectrometry
D7795 Test Method for Acidity in Ethanol and Ethanol Blends by Titration
D7923 Test Method for Water in Ethanol and Hydrocarbon Blends by Karl Fischer Titration
E203 Test Method for Water Using Volumetric Karl Fischer Titration
E1064 Test Method for Water in Organic Liquids by Coulometric Karl Fischer Titration
2.2 Government Standards:
United States Code of Federal Regulations, Title 40, Part 801090
2.3 SAE Papers:
SAE 2007–01–4006 A Model for Estimating Vapor Pressures of Commingled Ethanol Fuels
3. Terminology
3.1 For general terminology, refer to Terminology D4175.
3.2 Definitions:
3.2.1 denaturants, n—materials added to ethanol to make it unsuitable for beverage use under a formula approved by a regulatory
agency to prevent the imposition of beverage alcohol tax.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
A printed copy of the Code of Federal Regulations may be purchased from the U.S. Government Printing Office, Superintendent of Documents, 732 N. Capitol Street,
N.W., Mail Stop: SDE, Washington, DC 20401 or the online store at http://bookstore.gpo.gov/. The Code of Federal Regulations may be browsed online at
http://www.gpoaccess.gov/cfr/index.html.
Available from SAE International (SAE), 400 Commonwealth Dr., Warrendale, PA 15096-0001, http://www.sae.org.
D5798 − 21
3.2.1.1 Discussion—
Denaturants are only those materials added by the denaturer to comply with the approved formula; any materials absorbed later
are not denaturants. D4806
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
3.2.4 finished fuel, n—a homogeneous mixture of blendstocks and fuel additives meeting all specification and regulatory
requirements for its intended use at the location where sold. D4814
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.
3.2.6 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
3.2.7 hydrocarbon, n—a compound composed solely of hydrogen and carbon.
3.2.8 methanol, n—methyl alcohol, the chemical compound CH OH.
3.2.9 pHe, n—a measure of hydrogen ion activity, defined by Test Method D6423. D6423
3.2.9.1 Discussion—
The traditional pH measurement of hydrogen ion activity is in an aqueous system but the measurement done in Test Method D6423
is in a nearly anhydrous environment. D6423
3.3 Definitions of Terms Specific to This Standard:
3.3.1 hydrocarbon blendstock, n—a blending component composed of hydrocarbons which boil in the gasoline temperature
distillation range and trace amounts of naturally occurring compounds or additives composed of hydrogen, carbon, and other
elements such as sulfur, oxygen and nitrogen.
4. Ordering Information
4.1 The purchasing agency shall:
4.1.1 Indicate the season and locality in which the fuel is to be used,
4.1.2 If requested, ensure that the ethanol concentration meets the requirements for an alternative fuel for federal fleets.
4.1.2.1 The composition of alternative fuels in the United States is regulated by various government agencies and regulations
including the U.S. Department of Energy (DOE) and U.S. Environmental Protection Agency (EPA). With regard to fuel properties
including volatility, this specification can be more or less restrictive than DOE or EPA rules, regulations and waivers. To qualify
as an alternative fuel for federal fleet use in the United States, the ethanol blend is required to meet the U.S. Department of
Energy’s definition of alternative fuels, enacted under the Energy Policy Act of 1992 (Title III, Sec. 301). For ethanol, the Act
defines “alternative fuel” as a mixture containing denatured ethanol at a volume of “85 percent or more (or such other percentage,
but not less than 70 percent, as determined by the Secretary, by rule.).” Correcting for denaturant content, a blend of 70 % to 85 %
D5798 − 21
by volume denatured fuel ethanol contains 68 % to 83 % by volume ethanol as measured by Test Method D5501. The U.S.
government has other programs and definitions for alternative fuels.
4.1.2.2 Users of this specification are advised to check with the applicable regulatory agency for specific alternative fuel
requirements.
5. Ethanol Fuel Blends Performance Requirements
5.1 Ethanol Fuel Blends shall conform to the requirements of Table 1.
5.1.1 The components used to produce Ethanol Fuel Blends are limited to denatured fuel ethanol and hydrocarbon blendstock as
defined in 5.2.
5.1.2 The intentional addition of lead or phosphorus compounds to ethanol fuel blends is not permitted.
5.2 Hydrocarbon Blendstock blended with the denatured fuel ethanol shall meet the requirements of Table 2.
5.2.1 The hydrocarbon blendstock may be unleaded gasoline, gasoline blendstock for oxygenate blending (BOB), natural gasoline
or other hydrocarbons in the gasoline boiling range.
5.2.2 In the United States, 40 CFR Part 1090.640 provides an exemption for use of deposit control additives for ethanol fuel
blends. The hydrocarbon blendstock (gasoline) is exempt from the gasoline deposit control requirements in 40 CFR Part 1090.260.
5.3 Vapor pressure is varied for seasonal and climatic changes by providing four vapor pressure classes for ethanol fuel blends.
5.3.1 Class 1 encompasses geographical areas with 6-hour tenth percentile minimum ambient temperature of greater than 5 °C
(41 °F).
5.3.2 Class 2 encompasses geographical areas with 6-hour tenth percentile minimum ambient temperature of greater than −5 °C
(23 °F) but less than or equal to 5 °C (41°F).
5.3.3 Class 3 encompasses geographical areas with 6-hour tenth percentile minimum ambient temperature greater than −13 °C
(9 °F) but less than or equal to −5 °C (23°F).
5.3.4 Class 4 encompasses geographical areas with 6-hour tenth percentile minimum ambient temperature less than or equal to
−13 °C (9 °F).
A
TABLE 1 Requirements for Ethanol Fuel Blends
Properties Class Class 2 Class Class 4 Test Methods
B
1 3
Vapor pressure, kPa (psi) 38–62 48–65 59–83 66–103 D4953 or D5191
(5.5–9.0) (7.0–9.5) (8.5–12.0) (9.5–15.0)
C
All Classes
Ethanol Content, volume % 51–83 D5501
Water, % by volume (% by mass), max 0.8 (1.0) D7923, E203, or E1064
Methanol Content, max, volume % 0.5 D5501
Sulfur Content, max, mg/kg 80 D5453 or D7039
Acidity, (as acetic acid CH3COOH), 0.005 (40) [50] D7795
mass % (mg/L) [mg/kg], max
Solvent-washed gum content, 5 D381
max, mg/100 mL
Unwashed gum content, max, 20 D381
mg/100 mL
pHe 6.5 to 9.0 D6423
Inorganic chloride content, max, mg/kg 1 D7319 or D7328
Copper content, max, mg/L 0.07 D1688
A
For information on alternative fuels, see 4.1.2.1.
B
See 5.3.1 for volatility class criteria.
C
Ethanol content and selection of hydrocarbon blendstock are adjusted by the blender to meet vapor pressure requirements. See X1.3.2 for additional information and
guidance for blending.
D5798 − 21
TABLE 2 Requirements for Hydrocarbon Blendstock
Properties Test Methods
Distillation, end point, max, °C (°F) 225 (437) D86
Oxidation stability, minimum, minutes 240 D525
Copper Strip Corrosion, max No. 1 D130
Silver Strip Corrosion, max No. 1 D7667, D7671
A
Vapor pressure Report D4953, D5191
A
While not a requirement of this specification, the blender will need to know the
vapor pressure of the hydrocarbon blendstock in order to choose a suitable blend
ratio for the components to meet the vapor pressure requirement of a particular
volatility class.
5.3.5 There is a 10 % probability that the highest temperature of the six coldest consecutive hourly temperature readings of a 24 h
day will be colder than the 6 h tenth percentile minimum ambient temperature.
5.3.6 See 5.4.4 and 5.5.2 for seasonal and geographical distributions.
5.4 Regulatory and Other Requirements in the United States:
5.4.1 Ethanol content requirements for ethanol alternative fuel blends can be found in 4.1.2.1.
5.4.2 The denaturant for the denatured fuel ethanol used in making ethanol fuel blends shall meet the requirements of Section 5
in Specification D4806.
5.4.3 Ethanol fuel blends of any volatility class shall meet certain U.S. Environmental Protection Agency (EPA) regulations for
unleaded gasoline. See Appendix X2.
5.4.4 The United States seasonal and geographical distribution for the four vapor pressure classes is shown in Table 3.
5.5 Regulatory and Other Requirements Outside the United States:
5.5.1 Users of this specification are advised to consult with the applicable regulatory agency for specific requirements for their
jurisdictions.
5.5.2 Users of the specification in geographical areas outside the United States need to determine the 6-hour tenth percentile
minimum ambient temperatures for their geographic areas and times of year in order to select the appropriate classes of fuel.
6. Workmanship
6.1 The finished fuel blend shall be visually free of sediment, suspended or undissolved matter. It shall be clear and bright at the
fuel temperature at the point of custody transfer or at an alternative temperature agreed upon by the purchaser and seller.
NOTE 1—Finished fuel should be resistant to phase separation or undissolved matter at the lowest temperatures to which it is likely to be subjected,
dependent on the time and place of its intended use. See Specification D4814, Table X7.1 for guidance.
NOTE 2—Solubility is temperature dependent. As this fuel cools some high molecular weight additives can become insoluble.
6.2 The hydrocarbon blendstock for ethanol fuel blends should avoid the use of materials at concentrations that can separate from
solution at the expected temperatures of blending, storage, and use. If drag reducing agent (additive) (DRA) or deposit control
additive is used in the hydrocarbon blendstock distribution system, it should not be present in the product delivered to be used as
a hydrocarbon blendstock at a concentration or shear condition, which can separate from the denatured fuel ethanol under those
conditions.
6.2.1 In the United States, 40 CFR Part 1090.640 provides an exemption for use of deposit control additives for ethanol fuel
blends. Hydrocarbon blendstock (gasoline) that is used to produce ethanol fuel blends is exempt from the gasoline deposit control
requirements in 40 CFR Part 1090.260.
D5798 − 21
TABLE 3 United States Seasonal and Geographical Volatility Specifications for Ethanol Fuel Blends
NOTE 1—This schedule, subject to agreement between the purchaser and the seller, denotes the vapor pressure class of the fuel at the time and place
of bulk delivery to fuel-dispensing facilities for the end user. Shipments should anticipate this schedule.
NOTE 2—Where alternative classes are listed, either class is acceptable; the option shall be exercised by the seller.
NOTE 3—This schedule was developed using actual (versus altitude-adjusted) 6 h tenth percentile minimum ambient temperatures.
State Jan Feb March Apr May June July Aug Sep Oct Nov Dec
Alabama 2 2 2 2 2/1 1 1 1 1 1/2 2 2
Alaska
Southern Region 4 4/3 3 3/2 2 2/1 1 1/2 2/3 3 3/4 4
South Mainland 4 4 4 4 4/2 2 2/1 1/2 2/3 3/4 4 4
Arizona
N of 34° Latitude 3 3 3 3/2 2 2/1 1 1 1/2 2/3 3 3
S of 34° Latitude 2 2 2 2/1 1 1 1 1 1 1/2 2 2
Arkansas 3 3 3/2 2/1 1 1 1 1 1/2 2 2/3 3
A
California
North Coast 2 2 2 2 2/1 1 1 1 1 1/2 2 2
South Coast 2 2 2 2 2/1 1 1 1 1 1/2 2 2
Southeast 2 2 2 2 2/1 1 1 1 1 1/2 2 2
Interior 2 2 2 2 2 2/1 1 1 1 1/2 2 2
Colorado
E of 105° Longitude 4 4/3 3 3/2 2 2/1 1 1 1/2 2/3 3 3/4
W of 105° Longitude 4 4 4/3 3 3/2 2 2/1 1/2 2/3 3/4 4 4
Connecticut 4 4 4/3 3/2 2 2/1 1 1 1/2 2 2/4 4
Delaware 3 3 3/2 2 2/1 1 1 1 1/2 2 2/3 3
District of Columbia 3 3 3/2 2 2/1 1 1 1 1/2 2 2/3 3
Florida
N of 29° Latitude 2 2 2 2/1 1 1 1 1 1 1/2 2 2
S of 29° Latitude 2 2/1 1 1 1 1 1 1 1 1 1/2 2
Georgia 3 3/2 2 2/1 1 1 1 1 1 1/2 2 2/3
Hawaii 1 1 1 1 1 1 1 1 1 1 1 1
Idaho 4 4 4/3 3/2 2 2 2/1 1/2 2 2/3 3/4 4
Illinois
N of 40° Latitude 4 4 4/3 3/2 2 2/1 1 1 1/2 2/3 3/4 4
S of 40° Latitude 4 4/3 3 3/2 2/1 1 1 1 1/2 2/3 3/4 4
Indiana 4 4 4/3 3/2 2/1 1 1 1 1/2 2/3 3/4 4
Iowa 4 4 4 4/2 2 2/1 1 1 1/2 2/3 3/4 4
Kansas 4 4/3 3 3/2 2 2/1 1 1 1/2 2/3 3/4 4
Kentucky 3 3 3/2 2 2/1 1 1 1 1/2 2 2/3 3
Louisiana 2 2 2 2/1 1 1 1 1 1 1/2 2 2
Maine 4 4 4 4/2 2 2/1 1 1/2 2 2/3 3/4 4
Maryland 3 3 3/2 2 2/1 1 1 1 1/2 2 2/3 3
Massachusetts 4 4 4/3 3/2 2 2/1 1 1 1/2 2 2/4 4
Michigan
Lower Michigan 4 4 4/3 3/2 2 2/1 1 1/2 2 2/3 3/4 4
Upper Michigan 4 4 4 4/3 3/2 2/1 1 1/2 2 2/3 3/4 4
Minnesota 4 4 4 4/3 3/2 2/1 1 1/2 2 2/4 4 4
Mississippi 2 2 2 2/1 1 1 1 1 1 1/2 2 2
Missouri 4 4/3 3 3/2 2/1 1 1 1 1/2 2/3 3 3
Montana 4 4 4 4/3 3/2 2 2/1 1/2 2/3 3/4 4 4
Nebraska 4 4 4/3 3/2 2 2/1 1 1/2 2 2/3 3/4 4
Nevada
N of 38° Latitude 4 4 4/3 3/2 2 2 2/1 1/2 2 2/3 3/4 4
S of 38° Latitude 2 2 2 2/1 2/1 1 1 1 1 1/2 2 2
New Hampshire 4 4 4/3 3/2 2 2/1 1 1/2 2 2/3 3/4 4
New Jersey 3 3 3/2 2 2/1 1 1 1 1/2 2 2/3 3
New Mexico
N of 34° Latitude 4 4/3 3 3/2 2 2/1 1 1 1/2 2/3 3 3/4
S of 34° Latitude 3 3 3/2 2/1 1 1 1 1 1 1/2 2/3 3
New York
N of 42° Latitude 4 4 4 4/2 2 2/1 1 1/2 2 2/3 3/4 4
S of 42° Latitude 4 4 4/3 3/2 2/1 1 1 1 1/2 2 2/3 3/4
North Carolina 3 3 3/2 2 2/1 1 1 1 1/2 2/3 3 3
North Dakota 4 4 4 4/3 3/2 2/1 1 1/2 2 2/4 4 4
Ohio 4 4 4/3 3/2 2 2/1 1 1 1/2 2/3 3/4 4
Oklah
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