ASTM D7547-23

Standard Specification for Hydrocarbon Unleaded Aviation Gasoline

ABSTRACT
This specification establishes the requirements for purchases of Grade UL 91 unleaded aviation gasoline under contract and is intended primarily for use by purchasing agencies. It does not cover any other gasolines satisfactory for reciprocating aviation engines. The unleaded aviation gasoline, except as otherwise specified here, shall consist of blends of refined hydrocarbons derived from crude petroleum, natural gasoline, or blends thereof, with synthetic hydrocarbons or aromatic hydrocarbons, or both. Additives for electrical conductivity and corrosion inhibition, as well as certain types of antioxidants may be added separately, or in combination, in specified compositions and concentrations. Properly sampled specimens shall undergo test procedures and conform, accordingly, to the following requirements: knock value (motor octane number); density; distillation (initial boiling point, fuel evaporated, and final boiling point); recovery, residue and loss volumes; vapor pressure; freezing point; sulfur content; net heat of combustion; corrosion (copper strip); oxidation stability (potential gum); water reaction (volume change); and electrical conductivity.
SCOPE
1.1 This specification covers formulating specifications for purchases of aviation gasoline under contract and is intended primarily for use by purchasing agencies.  
1.2 Unleaded aviation gasoline defined by this specification is for use in engines and associated aircraft that are specifically approved by the engine and aircraft manufacturers. This fuel is not considered suitable for use in other engines and associated aircraft that are certified to use only leaded aviation gasolines of the same octane grade.  
1.3 This specification, unless otherwise provided, prescribes the required properties of unleaded aviation gasoline at the time and place of delivery.  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 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.  
1.6 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.

General Information

• Status: Published
• Publication Date: 30-Apr-2023
• ICS: 75.160.20 - Liquid fuels
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.J0.02 - Aviation Piston Engine Fuels

Relations

• Replaces: ASTM D7592-15a - Standard Specification for Specification for Grade 94 Unleaded Aviation Gasoline Certification and Test Fuel (Withdrawn 2016)
• Effective Date: 13-Dec-2016
• Refers: ASTM D1094-24 - Standard Test Method for Water Reaction of Aviation Fuels
• Effective Date: 01-Mar-2024
• Refers: ASTM D2700-24 - Standard Test Method for Motor Octane Number of Spark-Ignition Engine Fuel
• Effective Date: 01-Mar-2024
• Refers: ASTM D86-23a - Standard Test Method for Distillation of Petroleum Products and Liquid Fuels at Atmospheric Pressure
• Effective Date: 01-Dec-2023
• Refers: ASTM D86-23ae1 - Standard Test Method for Distillation of Petroleum Products and Liquid Fuels at Atmospheric Pressure
• Effective Date: 01-Dec-2023
• Refers: ASTM D2700-23b - Standard Test Method for Motor Octane Number of Spark-Ignition Engine Fuel
• Effective Date: 01-Nov-2023
• Refers: ASTM D4865-23 - Standard Guide for Generation and Dissipation of Static Electricity in Petroleum Fuel Systems
• Effective Date: 01-Nov-2023
• Refers: ASTM D2700-23a - Standard Test Method for Motor Octane Number of Spark-Ignition Engine Fuel
• Effective Date: 01-Oct-2023
• Refers: ASTM D5453-19a - Standard Test Method for Determination of Total Sulfur in Light Hydrocarbons, Spark Ignition Engine Fuel, Diesel Engine Fuel, and Engine Oil by Ultraviolet Fluorescence
• Effective Date: 01-Jul-2019
• Refers: ASTM D5059-14(2019) - Standard Test Methods for Lead in Gasoline by X-Ray Spectroscopy
• Effective Date: 01-May-2019
• Refers: ASTM D5191-18a - Standard Test Method for Vapor Pressure of Petroleum Products and Liquid Fuels (Mini Method)
• Effective Date: 01-Dec-2018
• Refers: ASTM D4809-18 - Standard Test Method for Heat of Combustion of Liquid Hydrocarbon Fuels by Bomb Calorimeter (Precision Method)
• Effective Date: 01-Jul-2018
• Refers: ASTM D909-17 - Standard Test Method for Supercharge Rating of Spark-Ignition Aviation Gasoline
• Effective Date: 01-Oct-2017
• Refers: ASTM D2700-17 - Standard Test Method for Motor Octane Number of Spark-Ignition Engine Fuel
• Effective Date: 01-Oct-2017
• Refers: ASTM D909-16 - Standard Test Method for Supercharge Rating of Spark-Ignition Aviation Gasoline
• Effective Date: 15-Dec-2016

Overview

ASTM D7547-23: Standard Specification for Hydrocarbon Unleaded Aviation Gasoline establishes the requirements for the procurement and use of Grade UL 91 unleaded aviation gasoline. Developed by ASTM International, this specification is primarily intended for purchasing agencies and suppliers involved in providing aviation fuels for aircraft and engines specifically approved for unleaded gasoline. The standard ensures that unleaded aviation gasolines meet critical quality and safety standards at the time and place of delivery, addressing properties essential for safe and efficient aircraft operation.

This standard addresses a growing demand for unleaded aviation gasoline products, aligned with environmental and regulatory initiatives to reduce lead emissions in aviation fuel. It meticulously details performance properties, compositional requirements, and approved additives to support reliable and consistent fuel quality.

Key Topics

• Scope of Applicability: Applies exclusively to Grade UL 91 unleaded aviation gasoline for engines and aircraft certified for its use. It is not valid for engines or aircraft requiring leaded fuels of similar octane grades.
• Fuel Composition: Unleaded aviation gasoline under this standard must consist of refined hydrocarbons from crude oil, natural gasoline, or their blends, potentially combined with synthetic or aromatic hydrocarbons.
• Additives: Certain additives may be included to enhance fuel properties:
  • Electrical conductivity improvers
  • Corrosion inhibitors
  • Specific antioxidants
  • Approved dyes for identification and compliance
• Required Fuel Properties: Quality limits are specified for:
  • Knock value (motor octane number)
  • Density and distillation characteristics
  • Vapor pressure, volatility, and boiling points
  • Sulfur content and net heat of combustion
  • Corrosion potential, oxidation stability, and water reaction
  • Electrical conductivity
• Testing and Certification: Employs multiple ASTM test methods (e.g., D2700 for octane, D86 for distillation, D323 for vapor pressure) to verify fuel performance and composition.
• Sampling and Reporting: Outlines procedures for manual and automatic fuel sampling, emphasizing the importance of preventing contamination and ensuring accurate laboratory results.
• Safety Considerations: Calls for users to establish suitable safety, health, and environmental practices before handling or applying the fuel.

Applications

ASTM D7547-23 unleaded aviation gasoline is specifically engineered for use in certified aircraft and engines designed to operate with unleaded fuel. Practical applications include:

• Small Aircraft Operations: Enables operators of piston-engine aircraft to utilize unleaded gasoline while maintaining required engine performance.
• Purchasing and Contracting: Purchasing agencies and fuel suppliers rely on this standard to specify product requirements, conduct quality checks, and validate conformance before delivery.
• Environmental Compliance: Supports efforts to reduce lead in aviation fuels, contributing to greener, regulatory-compliant airport and aviation operations.
• Fuel Quality Assurance: Ensures that the fuel delivered meets stringent safety and performance benchmarks, minimizing risks of engine knock, vapor lock, icing, or corrosion.
• Additive Management: Guides proper selection and use of additives to control properties such as electrical conductivity and oxidation stability, resulting in improved fuel handling and longer storage life.

Related Standards

For implementation and assessment, ASTM D7547-23 references various related ASTM standards and guides, ensuring comprehensive fuel evaluation and safety:

• ASTM D2700 - Motor Octane Number of Spark-Ignition Engine Fuel
• ASTM D86 - Distillation of Petroleum Products and Liquid Fuels
• ASTM D323/D5191 - Vapor Pressure of Petroleum Products
• ASTM D873 - Oxidation Stability of Aviation Fuels
• ASTM D1094 - Water Reaction of Aviation Fuels
• ASTM D2622, D4294, D5453, D7220 - Sulfur Content Determination
• ASTM D4057/D4177 - Sampling Procedures
• ASTM D2392 - Color of Dyed Aviation Gasolines
• ASTM D4865 - Generation and Dissipation of Static Electricity in Petroleum Fuels

These standards collectively enable thorough specification, testing, and quality assurance processes vital for unleaded aviation gasoline applications.

Keywords: ASTM D7547-23, unleaded aviation gasoline, UL 91, aviation fuel specification, avgas, aviation gasoline standard, unleaded avgas, fuel quality, aviation fuel additives, ASTM aviation standards.

Standards Content (Sample)

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.
Designation: D7547 − 23
Standard Specification for
Hydrocarbon Unleaded Aviation Gasoline
This standard is issued under the fixed designation D7547; 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* D130 Test Method for Corrosiveness to Copper from Petro-
leum Products by Copper Strip Test
1.1 This specification covers formulating specifications for
D323 Test Method for Vapor Pressure of Petroleum Products
purchases of aviation gasoline under contract and is intended
(Reid Method)
primarily for use by purchasing agencies.
D873 Test Method for Oxidation Stability of Aviation Fuels
1.2 Unleaded aviation gasoline defined by this specification
(Potential Residue Method)
is for use in engines and associated aircraft that are specifically
D909 Test Method for Supercharge Rating of Spark-Ignition
approved by the engine and aircraft manufacturers. This fuel is
Aviation Gasoline
not considered suitable for use in other engines and associated
D1094 Test Method for Water Reaction of Aviation Fuels
aircraft that are certified to use only leaded aviation gasolines
D1298 Test Method for Density, Relative Density, or API
of the same octane grade.
Gravity of Crude Petroleum and Liquid Petroleum Prod-
1.3 This specification, unless otherwise provided, prescribes
ucts by Hydrometer Method
the required properties of unleaded aviation gasoline at the
D2386 Test Method for Freezing Point of Aviation Fuels
time and place of delivery.
D2392 Test Method for Color of Dyed Aviation Gasolines
1.4 The values stated in SI units are to be regarded as
D2622 Test Method for Sulfur in Petroleum Products by
standard. No other units of measurement are included in this
Wavelength Dispersive X-ray Fluorescence Spectrometry
standard.
D2624 Test Methods for Electrical Conductivity of Aviation
and Distillate Fuels
1.5 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the D2700 Test Method for Motor Octane Number of Spark-
responsibility of the user of this standard to establish appro- Ignition Engine Fuel
priate safety, health, and environmental practices and deter- D3237 Test Method for Lead in Gasoline by Atomic Absorp-
mine the applicability of regulatory limitations prior to use. tion Spectroscopy
1.6 This international standard was developed in accor-
D3338 Test Method for Estimation of Net Heat of Combus-
dance with internationally recognized principles on standard-
tion of Aviation Fuels
ization established in the Decision on Principles for the
D4052 Test Method for Density, Relative Density, and API
Development of International Standards, Guides and Recom-
Gravity of Liquids by Digital Density Meter
mendations issued by the World Trade Organization Technical
D4057 Practice for Manual Sampling of Petroleum and
Barriers to Trade (TBT) Committee.
Petroleum Products
D4171 Specification for Fuel System Icing Inhibitors
2. Referenced Documents
D4177 Practice for Automatic Sampling of Petroleum and
2.1 ASTM Standards: Petroleum Products
D86 Test Method for Distillation of Petroleum Products and
D4294 Test Method for Sulfur in Petroleum and Petroleum
Liquid Fuels at Atmospheric Pressure Products by Energy Dispersive X-ray Fluorescence Spec-
trometry
D4306 Practice for Aviation Fuel Sample Containers for
Tests Affected by Trace Contamination
This specification is under the jurisdiction of ASTM Committee D02 on
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
D4529 Test Method for Estimation of Net Heat of Combus-
Subcommittee D02.J0.02 on Aviation Piston Engine Fuels.
tion of Aviation Fuels
Current edition approved May 1, 2023. Published May 2023. Originally
D4809 Test Method for Heat of Combustion of Liquid
approved in 2009. Last previous edition approved in 2021 as D7547 – 21. DOI:
10.1520/D7547-23.
Hydrocarbon Fuels by Bomb Calorimeter (Precision
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Method)
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
D4865 Guide for Generation and Dissipation of Static Elec-
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. tricity in Petroleum Fuel Systems
*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
D7547 − 23
D5006 Test Method for Measurement of Fuel System Icing 5.2.1.2 The only blue dye that shall be present in the
Inhibitors (Ether Type) in Aviation Fuels finished gasoline shall be essentially 1,4-
D5059 Test Methods for Lead and Manganese in Gasoline dialkylaminoanthraquinone.
by X-Ray Fluorescence Spectroscopy 5.2.2 Antioxidants—The following oxidation inhibitors may
D5191 Test Method for Vapor Pressure of Petroleum Prod- be added to the gasoline separately, or in combination, in total
ucts and Liquid Fuels (Mini Method) concentration not to exceed 12 mg of inhibitor (not including
D5453 Test Method for Determination of Total Sulfur in weight of solvent) per litre of fuel.
Light Hydrocarbons, Spark Ignition Engine Fuel, Diesel 5.2.2.1 2,6-ditertiary butyl-4-methylphenol.
Engine Fuel, and Engine Oil by Ultraviolet Fluorescence 5.2.2.2 2,4-dimethyl-6-tertiary butylphenol.
D6469 Guide for Microbial Contamination in Fuels and Fuel 5.2.2.3 2,6-ditertiary butylphenol.
Systems 5.2.2.4 75 % minimum 2,6-ditertiary butylphenol plus 25 %
D7220 Test Method for Sulfur in Automotive, Heating, and maximum mixed tertiary and tritertiary butylphenols.
Jet Fuels by Monochromatic Energy Dispersive X-ray 5.2.2.5 75 % minimum di- and tri-isopropyl phenols plus
Fluorescence Spectrometry 25 % maximum di- and tri-tertiary butylphenols.
E29 Practice for Using Significant Digits in Test Data to 5.2.2.6 72 % minimum 2,4-dimethyl-6-tertiary butylphenol
Determine Conformance with Specifications plus 28 % maximum monomethyl and dimethyl tertiary
butylphenols.
3. Terminology
5.2.2.7 N,N’-di-isopropyl-para-phenylenediamine.
3.1 Definitions: 5.2.2.8 N,N’-di-secondary-butyl-para-phenylenediamine.
5.2.3 Fuel System Icing Inhibitor (FSII)—One of the fol-
3.1.1 unleaded aviation gasoline, n—gasoline possessing
specific properties suitable for fueling aircraft powered by lowing may be used:
5.2.3.1 Isopropyl Alcohol (IPA, propan-2-ol), in accordance
reciprocating spark ignition engines, where lead is not inten-
tionally added for the purpose of enhancing octane perfor- with the requirements of Specification D4171 (Type II). May
be used in concentrations recommended by the aircraft manu-
mance.
3.1.1.1 Discussion—Principal properties include volatility facturer when required by the aircraft owner/operator.
limits, stability, detonation-free performance in the engine for
NOTE 2—Addition of isopropyl alcohol (IPA) can reduce knock ratings
which it is intended, and suitability for low temperature
below minimum specification values (see X1.2.3).
performance.
5.2.3.2 Di-Ethylene Glycol Monomethyl Ether (Di-EGME),
3.2 Abbreviations:
conforming to the requirements of Specification D4171 (Type
3.2.1 UL—unleaded.
III) may be used in concentrations of 0.10 % volume to 0.15 %
volume when required by the aircraft owner/operator.
4. Classification
5.2.3.3 Test Method D5006 may be used to determine the
4.1 Two grades of unleaded aviation gasoline are provided,
concentration of Di-EGME in aviation fuels.
known as: Grades UL91 and UL94.
5.2.4 Electrical Conductivity Additive—Stadis® 450 in
concentrations up to 3 mg ⁄L is permitted. When loss of fuel
NOTE 1—Grades UL91 and UL94 are based on their octane number as
conductivity necessitates retreatment with electrical conductiv-
measured by Test Method D2700 motor method.
ity additive, further addition is permissible up to a maximum
5. Materials and Manufacture
cumulative level of 5 mg ⁄L of Stadis® 450.
5.2.5 Corrosion Inhibitor Additive—The following corro-
5.1 Unleaded aviation gasoline, except as otherwise speci-
sion inhibitors may be added to the gasoline in concentrations
fied in this specification, shall consist of blends of refined
not to exceed the maximum allowable concentration (MAC)
hydrocarbons derived from crude petroleum, natural gasoline,
listed for each additive.
or blends, thereof, with synthetic hydrocarbons or aromatic
hydrocarbons, or both.
DCI-4A MAC = 24 g/m
DCI-6A MAC = 15 g/m
5.2 Additives—These may be added to each grade of un- 3
HITEC 580 MAC = 22.5 g/m
leaded aviation gasoline in the amount and of the composition NALCO 5403 MAC = 22.5 g/m
NALCO 5405 MAC = 11.0 g/m
specified in the following list of approved materials. The
UNICOR J MAC = 22.5 g/m
quantities and types shall be declared by the manufacturer. 3
SPEC-AID 8Q22 MAC = 24.0 g/m
TOLAD 351 MAC = 24.0 g/m
Additives added after the point of manufacture shall also be
TOLAD 4410 MAC = 22.5 g/m
declared.
5.2.1 Dyes—The maximum concentration limits in each
6. Detailed Requirements
grade of gasoline are specified in Table 1.
6.1 The unleaded aviation gasoline shall conform to the
5.2.1.1 The only red dye that shall be present in the finished
requirements prescribed in Table 1.
gasoline shall be essentially alkyl derivatives of azobenzene-
4-azo-2-naphthol.
Supporting data have been filed at ASTM International Headquarters and may
be obtained by requesting Research Report RR:D02-1526. Contact ASTM Customer
Supporting data have been filed at ASTM International Headquarters and may Service at [e-mail].
be obtained by requesting Research Report RR:D02-1859. Contact ASTM Customer Stadis® 450 is a registered trademark marketed by Innospec, Inc., Innospec
Service at [e-mail]. Manufacturing Park, Oil Sites Road, Ellesmere Port, Cheshire, CH65 4EY, UK.
D7547 − 23
A
TABLE 1 Detailed Requirements for Unleaded Aviation Gasolines
Grade Grade
B
Property ASTM Test Method
UL91 UL94
COMBUSTION
C
Net heat of combustion, MJ/kg min 43.5 43.5 D4529 or D3338
D
Octane Rating
E
Knock value, Motor Octane Number min 91.0 94.0 D2700
COMPOSITION
Sulfur, mass percent max 0.05 0.05 D2622, D4294, D5453, or
F
D7220
Tetraethyl lead, g Pb/L max 0.0130 0.0130 D3237 or D5059
G
COLOR Red Purple D2392
H
Dye content , mg/L
Red dye max 2.3 0.9
I
Blue dye max 0.2 1.2
Requirements for All Grades
VOLATILITY
J
Vapor pressure, 38 °C, kPa min 38.0 D323 or D5191
max 49.0
Density at 15 °C, kg/m Report D1298 or D4052
Distillation, °C D86
Initial boiling point Report
Fuel Evaporated
10 volume percent at °C max 75
40 volume percent at °C min 75
50 volume percent at °C max 105
90 volume percent at °C max 135
Final boiling point max 170
Sum of 10 % + 50 % evaporated tem- min 135
peratures
Recovery volume percent min 97
Residue volume percent max 1.5
Loss volume percent max 1.5
FLUIDITY
K
Freezing point, °C max −58 D2386
CORROSION
Copper strip, 2 h at 100 °C max No. 1 D130
CONTAMINANTS
Oxidation stability, mg/100 mL D873
L
(5 h aging)
Potential gum max 6
Lead precipitate max 3
Water reaction D1094
Volume change, mL max ±2
OTHER
M
Electrical conductivity, pS/m max 600 D2624
A
For compliance of test results against the requirements of Table 1, see 6.2.
B
The test methods indicated in this table are referred to in Section 10.
C
For all grades use either Eq 1 or Table 1 in Test Method D4529 or Eq 2 in Test Method D3338. Test Method D4809 may be used as an alternative. In case of dispute,
Test Method D4809 shall be used.
D
If mutually agreed upon between the purchaser and supplier, a minimum 98 octane requirement as per Test Method D909 may be specified.
E
Knock ratings shall be reported to the nearest 0.1 octane/performance number.
F
Test Method D2622 shall be the referee sulfur detection method.
G
A two-year transition to this new standard has been agreed to assist producers of aviation gasoline, ending December 31, 2024. During this period batches of grade UL91
or UL94 are permitted to be colorless or have significantly reduced color while fully meeting the requirements of D7547. Supporting data on the use of dyes in these fuel
grades has been filed at ASTM International Headquarters and may be obtained by requesting Research Report RR:D02-2049. Contact ASTM Customer Service at
[e-mail].
H
The maximum dye concentrations shown do not include solvent in dyes supplied in liquid form.
I
Inclusion of blue dye in UL91 is non-mandatory. 0.2 mg ⁄L maximum is permitted to simplify tank turnover where the previous grade contained blue dye.
J
Test Method D5191 shall be the referee vapor pressure method.
K
If no crystals have appeared on cooling to −58 °C, the freezing point may be reported as less than −58 °C.
L
If mutually agreed upon between the purchaser and the supplier, a 16 h aging gum requirement may be specified instead of the 5 h aging gum test; in such case the
gum content shall not exceed 10 mg/100 mL and the visible lead precipitate shall not exceed 4 mg/100 mL. In such fuel the permissible antioxidant shall not exceed
24 mg ⁄L.
M
Applies only when an electrical conductivity additive is used; when a customer specifies fuel containing conductivity additive, the following conductivity limits shall apply
under the condition at point of use:
Minimum 50 pS/m
Maximum 600 pS ⁄m.
The supplier shall report the amount of additive added.
D7547 − 23
6.2 Test results shall not exceed the maximum or be less 10. Test Methods
than the minimum values specified in Table 1. No allowance
10.1 The requirements enumerated in this specification shall
shall be made for the precision of the test methods. To
be determined in accordance with the following ASTM test
determine the conformance to the specification requirement, a
methods:
test result may be rounded to the same number of significant
10.1.1 Knock Value (MON)—Test Method D2700.
figures as in Table 1 using Practice E29. Where multiple
determinations are made, the average result, rounded according
10.1.2 Density—Test Methods D1298 or D4052.
to Practice E29, shall be used.
10.1.3 Distillation—Test Method D86.
7. Workmanship, Finish, and Appearance 10.1.4 Vapor Pressure—Test Methods D323 or D5191.
10.1.5 Freezing Point—Test Method D2386.
7.1 The unleaded aviation gasoline specified in this speci-
fication shall be free from undissolved water, sediment, and
10.1.6 Sulfur—Test Methods D2622, D4294, D5453, or
suspended matter. The odor of the fuel shall not be nauseating
D7220.
or irritating. No substances of known dangerous toxicity under
10.1.7 Net Heat of Combustion—Test Methods D4529,
usual conditions of handling and use shall be present.
D3338, or D4809.
8. Sampling
10.1.8 Corrosion (Copper Strip)—Test Method D130, 2 h
test at 100 °C in bomb.
8.1 Because of the importance of proper sampling proce-
dures in establishing fuel quality, use the appropriate proce- 10.1.9 Potential Gum—Test Method D873 except that wher-
dures in Practice D4057 or Practice D4177.
ever the letter X occurs (referring to oxidation time) insert the
8.1.1 Although automatic sampling following Practice
number 5, designating the number of hours prescribed in this
D4177 may be useful in certain situations, initial refinery
specification.
specification compliance testing shall be performed on a
10.1.10 Water Reaction—Test Method D1094.
sample taken following procedures in Practice D4057.
10.1.11 Electrical Conductivity—Test Method D2624.
8.2 A number of unleaded aviation gasoline properties,
10.1.12 Lead Content—Test Method D3237 and D5059.
including copper corrosion, electrical conductivity, and others
10.1.13 Color—Test Method D2392.
are very sensitive to trace contamination which can originate
from sample containers. For recommended sample containers,
11. Keywords
refer to Practice D4306.
11.1 Avgas; aviation gasoline; gasoline; unleaded Avgas;
9. Report
unleaded aviation gasoline
9.1 The type and number of reports to ensure conformance
with the requirements of this specification shall be mutually
agreed to by the purchaser and the supplier of the unleaded
aviation gasoline.
APPENDIX
(Nonmandatory Information)
X1. PERFORMANCE CHARACTERISTICS OF UNLEADED AVIATION GASOLINE
X1.1 Introduction aviation engines; however, certain equipment or conditions of
use may require fuels having other characteristics.
X1.1.1 Unleaded aviation gasoline is a complex mixture of
X1.1.3 Specifications covering antiknock quality defines the
relatively volatile hydrocarbons that vary widely in their
grade of unleaded aviation gasoline. The other requirements
physical and chemical properties. T
...

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: D7547 − 21 D7547 − 23
Standard Specification for
Hydrocarbon Unleaded Aviation Gasoline
This standard is issued under the fixed designation D7547; 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 specification covers formulating specifications for purchases of aviation gasoline under contract and is intended primarily
for use by purchasing agencies.
1.2 Unleaded aviation gasoline defined by this specification is for use in engines and associated aircraft that are specifically
approved by the engine and aircraft manufacturers. This fuel is not considered suitable for use in other engines and associated
aircraft that are certified to use only leaded aviation gasolines of the same octane grade.
1.3 This specification, unless otherwise provided, prescribes the required properties of unleaded aviation gasoline at the time and
place of delivery.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5 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.
1.6 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:
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
D323 Test Method for Vapor Pressure of Petroleum Products (Reid Method)
D873 Test Method for Oxidation Stability of Aviation Fuels (Potential Residue Method)
D909 Test Method for Supercharge Rating of Spark-Ignition Aviation Gasoline
D1094 Test Method for Water Reaction of Aviation Fuels
D1298 Test Method for Density, Relative Density, or API Gravity of Crude Petroleum and Liquid Petroleum Products by
Hydrometer Method
D2386 Test Method for Freezing Point of Aviation Fuels
This specification is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcommittee
D02.J0.02 on Aviation Piston Engine Fuels.
Current edition approved May 1, 2021May 1, 2023. Published June 2021May 2023. Originally approved in 2009. Last previous edition approved in 20182021 as
D7547 – 18a.D7547 – 21. DOI: 10.1520/D7547-21.10.1520/D7547-23.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*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
D7547 − 23
D2392 Test Method for Color of Dyed Aviation Gasolines
D2622 Test Method for Sulfur in Petroleum Products by Wavelength Dispersive X-ray Fluorescence Spectrometry
D2624 Test Methods for Electrical Conductivity of Aviation and Distillate Fuels
D2700 Test Method for Motor Octane Number of Spark-Ignition Engine Fuel
D3237 Test Method for Lead in Gasoline by Atomic Absorption Spectroscopy
D3338 Test Method for Estimation of Net Heat of Combustion of Aviation Fuels
D4052 Test Method for Density, Relative Density, and API Gravity of Liquids by Digital Density Meter
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
D4171 Specification for Fuel System Icing Inhibitors
D4177 Practice for Automatic Sampling of Petroleum and Petroleum Products
D4294 Test Method for Sulfur in Petroleum and Petroleum Products by Energy Dispersive X-ray Fluorescence Spectrometry
D4306 Practice for Aviation Fuel Sample Containers for Tests Affected by Trace Contamination
D4529 Test Method for Estimation of Net Heat of Combustion of Aviation Fuels
D4809 Test Method for Heat of Combustion of Liquid Hydrocarbon Fuels by Bomb Calorimeter (Precision Method)
D4865 Guide for Generation and Dissipation of Static Electricity in Petroleum Fuel Systems
D5006 Test Method for Measurement of Fuel System Icing Inhibitors (Ether Type) in Aviation Fuels
D5059 Test Methods for Lead and Manganese in Gasoline by X-Ray Fluorescence Spectroscopy
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
D6469 Guide for Microbial Contamination in Fuels and Fuel Systems
D7220 Test Method for Sulfur in Automotive, Heating, and Jet Fuels by Monochromatic Energy Dispersive X-ray Fluorescence
Spectrometry
E29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
3. Terminology
3.1 Definitions:
3.1.1 unleaded aviation gasoline, n—gasoline possessing specific properties suitable for fueling aircraft powered by reciprocating
spark ignition engines, where lead is not intentionally added for the purpose of enhancing octane performance.
3.1.1.1 Discussion—
Principal properties include volatility limits, stability, detonation-free performance in the engine for which it is intended, and
suitability for low temperature performance.
3.2 Abbreviations:
3.2.1 UL—unleaded.
4. Classification
4.1 Two grades of unleaded aviation gasoline are provided, known as: Grades UL91 and UL94.
NOTE 1—Grades UL91 and UL94 are based on their octane number as measured by Test Method D2700 motor method.
5. Materials and Manufacture
5.1 Unleaded aviation gasoline, except as otherwise specified in this specification, shall consist of blends of refined hydrocarbons
derived from crude petroleum, natural gasoline, or blends, thereof, with synthetic hydrocarbons or aromatic hydrocarbons, or both.
5.2 Additives—These may be added to each grade of unleaded aviation gasoline in the amount and of the composition specified
in the following list of approved materials. The quantities and types shall be declared by the manufacturer. Additives added after
the point of manufacture shall also be declared.
5.2.1 Dyes—The maximum concentration limits in each grade of gasoline are specified in Table 1.
Supporting data have been filed at ASTM International Headquarters and may be obtained by requesting Research Report RR:D02-1859. Contact ASTM Customer
Service at [e-mail].
D7547 − 23
A
TABLE 1 Detailed Requirements for Unleaded Aviation Gasolines
Grade
B
Property Grade ASTM Test Method
UL94
UL91
Property
COMBUSTION
D
Net heat of combustion, MJ/kg min 43.5 43.5 D4529 or D3338
C
Net heat of combustion, MJ/kg min 43.5 43.5 D4529 or D3338
C
Octane Rating
D
Octane Rating
E
Knock value, Motor Octane Number min 91.0 94.0 D2700
COMPOSITION
Sulfur, mass percent max 0.05 0.05 D2622, D4294, D5453, or
F
D7220
Tetraethyl lead, g Pb/L max 0.0130 0.0130 D3237 or D5059
G
COLOR Red Purple D2392
H
Dye content , mg/L
Red dye max 2.3 0.9
I
Blue dye max 0.2 1.2
Requirements for All Grades
VOLATILITY
G
Vapor pressure, 38 °C, kPa min 38.0 D323 or D5191
max 49.0
J
Vapor pressure, 38 °C, kPa min 38.0 D323 or D5191
max 49.0
Density at 15 °C, kg/m Report D1298 or D4052
Distillation, °C D86
Initial boiling point Report
Fuel Evaporated
10 volume percent at °C max 75
40 volume percent at °C min 75
50 volume percent at °C max 105
90 volume percent at °C max 135
Final boiling point max 170
Sum of 10 % + 50 % evaporated tem- min 135
peratures
Recovery volume percent min 97
Residue volume percent max 1.5
Loss volume percent max 1.5
FLUIDITY
H
Freezing point, °C max −58 D2386
K
Freezing point, °C max −58 D2386
CORROSION
Copper strip, 2 h at 100 °C max No. 1 D130
CONTAMINANTS
Oxidation stability, mg/100 mL D873
I
(5 h aging)
Oxidation stability, mg/100 mL D873
L
(5 h aging)
Potential gum max 6
Lead precipitate max 3
Water reaction D1094
Volume change, mL max ±2
OTHER
J
Electrical conductivity, pS/m max 600 D2624
M
Electrical conductivity, pS/m max 600 D2624
A
For compliance of test results against the requirements of Table 1, see 6.2.
B
The test methods indicated in this table are referred to in Section 10.
C
If mutually agreed upon between the purchaser and supplier, a minimum 98 octane requirement as per Test Method D909 may be specified.
C
For all grades use either Eq 1 or Table 1 in Test Method D4529 or Eq 2 in Test Method D3338. Test Method D4809 may be used as an alternative. In case of dispute,
Test Method D4809 shall be used.
D
If mutually agreed upon between the purchaser and supplier, a minimum 98 octane requirement as per Test Method D909 may be specified.
E
Knock ratings shall be reported to the nearest 0.1 octane/performance number.
F
Test Method D2622 shall be the referee sulfur detection method.
G
A two-year transition to this new standard has been agreed to assist producers of aviation gasoline, ending December 31, 2024. During this period batches of grade UL91
or UL94 are permitted to be colorless or have significantly reduced color while fully meeting the requirements of D7547. Supporting data on the use of dyes in these fuel
grades has been filed at ASTM International Headquarters and may be obtained by requesting Research Report RR:D02-2049. Contact ASTM Customer Service at
[e-mail].
H
The maximum dye concentrations shown do not include solvent in dyes supplied in liquid form.
I
Inclusion of blue dye in UL91 is non-mandatory. 0.2 mg ⁄L maximum is permitted to simplify tank turnover where the previous grade contained blue dye.
J
Test Method D5191 shall be the referee vapor pressure method.
K
If no crystals have appeared on cooling to −58 °C, the freezing point may be reported as less than −58 °C.
L
If mutually agreed upon between the purchaser and the supplier, a 16 h aging gum requirement may be specified instead of the 5 h aging gum test; in such case the
gum content shall not exceed 10 mg/100 mL and the visible lead precipitate shall not exceed 4 mg/100 mL. In such fuel the permissible antioxidant shall not exceed
24 mg ⁄L.
D7547 − 23
M
Applies only when an electrical conductivity additive is used; when a customer specifies fuel containing conductivity additive, the following conductivity limits shall apply
under the condition at point of use:
Minimum 50 pS/m
Maximum 600 pS ⁄m.
The supplier shall report the amount of additive added.
D7547 − 23
5.2.1.1 The only red dye that shall be present in the finished gasoline shall be essentially alkyl derivatives of azobenzene-4-azo-
2-naphthol.
5.2.1.2 The only blue dye that shall be present in the finished gasoline shall be essentially 1,4-dialkylaminoanthraquinone.
5.2.2 Antioxidants—The following oxidation inhibitors may be added to the gasoline separately, or in combination, in total
concentration not to exceed 12 mg of inhibitor (not including weight of solvent) per litre of fuel.
5.2.2.1 2,6-ditertiary butyl-4-methylphenol.
5.2.2.2 2,4-dimethyl-6-tertiary butylphenol.
5.2.2.3 2,6-ditertiary butylphenol.
5.2.2.4 75 % minimum 2,6-ditertiary butylphenol plus 25 % maximum mixed tertiary and tritertiary butylphenols.
5.2.2.5 75 % minimum di- and tri-isopropyl phenols plus 25 % maximum di- and tri-tertiary butylphenols.
5.2.2.6 72 % minimum 2,4-dimethyl-6-tertiary butylphenol plus 28 % maximum monomethyl and dimethyl tertiary butylphenols.
5.2.2.7 N,N’-di-isopropyl-para-phenylenediamine.
5.2.2.8 N,N’-di-secondary-butyl-para-phenylenediamine.
5.2.3 Fuel System Icing Inhibitor (FSII)—One of the following may be used:
5.2.3.1 Isopropyl Alcohol (IPA, propan-2-ol), in accordance with the requirements of Specification D4171 (Type II). May be used
in concentrations recommended by the aircraft manufacturer when required by the aircraft owner/operator.
NOTE 2—Addition of isopropyl alcohol (IPA) can reduce knock ratings below minimum specification values (see X1.2.3).
5.2.3.2 Di-Ethylene Glycol Monomethyl Ether (Di-EGME), conforming to the requirements of Specification D4171 (Type III) may
be used in concentrations of 0.10 % volume to 0.15 % volume when required by the aircraft owner/operator.
5.2.3.3 Test Method D5006 may be used to determine the concentration of Di-EGME in aviation fuels.
5.2.4 Electrical Conductivity Additive—Stadis® 450 in concentrations up to 3 mg ⁄L is permitted. When loss of fuel conductivity
necessitates retreatment with electrical conductivity additive, further addition is permissible up to a maximum cumulative level of
5 mg ⁄L of Stadis® 450.
5.2.5 Corrosion Inhibitor Additive—The following corrosion inhibitors may be added to the gasoline in concentrations not to
exceed the maximum allowable concentration (MAC) listed for each additive.
DCI-4A MAC = 24 g/m
DCI-6A MAC = 15 g/m
HITEC 580 MAC = 22.5 g/m
NALCO 5403 MAC = 22.5 g/m
NALCO 5405 MAC = 11.0 g/m
UNICOR J MAC = 22.5 g/m
SPEC-AID 8Q22 MAC = 24.0 g/m
TOLAD 351 MAC = 24.0 g/m
TOLAD 4410 MAC = 22.5 g/m
Supporting data have been filed at ASTM International Headquarters and may be obtained by requesting Research Report RR:D02-1526. Contact ASTM Customer
Service at [e-mail].
Stadis® 450 is a registered trademark marketed by Innospec, Inc., Innospec Manufacturing Park, Oil Sites Road, Ellesmere Port, Cheshire, CH65 4EY, UK.
D7547 − 23
6. Detailed Requirements
6.1 The unleaded aviation gasoline shall conform to the requirements prescribed in Table 1.
6.2 Test results shall not exceed the maximum or be less than the minimum values specified in Table 1. No allowance shall be
made for the precision of the test methods. To determine the conformance to the specification requirement, a test result may be
rounded to the same number of significant figures as in Table 1 using Practice E29. Where multiple determinations are made, the
average result, rounded according to Practice E29, shall be used.
7. Workmanship, Finish, and Appearance
7.1 The unleaded aviation gasoline specified in this specification shall be free from undissolved water, sediment, and suspended
matter. The odor of the fuel shall not be nauseating or irritating. No substances of known dangerous toxicity under usual conditions
of handling and use shall be present.
8. Sampling
8.1 Because of the importance of proper sampling procedures in establishing fuel quality, use the appropriate procedures in
Practice D4057 or Practice D4177.
8.1.1 Although automatic sampling following Practice D4177 may be useful in certain situations, initial refinery specification
compliance testing shall be performed on a sample taken following procedures in Practice D4057.
8.2 A number of unleaded aviation gasoline properties, including copper corrosion, electrical conductivity, and others are very
sensitive to trace contamination which can originate from sample containers. For recommended sample containers, refer to Practice
D4306.
9. Report
9.1 The type and number of reports to ensure conformance with the requirements of this specification shall be mutually agreed
to by the purchaser and the supplier of the unleaded aviation gasoline.
10. Test Methods
10.1 The requirements enumerated in this specification shall be determined in accordance with the following ASTM test methods:
10.1.1 Knock Value (MON)—Test Method D2700.
10.1.2 Density—Test Methods D1298 or D4052.
10.1.3 Distillation—Test Method D86.
10.1.4 Vapor Pressure—Test Methods D323 or D5191.
10.1.5 Freezing Point—Test Method D2386.
10.1.6 Sulfur—Test Methods D2622, D4294, D5453, or D7220.
10.1.7 Net Heat of Combustion—Test Methods D4529, D3338, or D4809.
10.1.8 Corrosion (Copper Strip)——TestTest Method D130, 2 h test at 100 °C in bomb.
10.1.9 Potential Gum—Test Method D873 except that wherever the letter X occurs (referring to oxidation time) insert the number
5, designating the number of hours prescribed in this specification.
10.1.10 Water Reaction—Test Method D1094.
10.1.11 Electrical Conductivity—Test Method D2624.
D7547 − 23
10.1.12 Lead Content—Test Method D3237 and D5059.
10.1.13 Color—Test Method D2392.
11. Keywords
11.1 Avgas; aviation gasoline; gasoline; unleaded Avgas; unleaded aviation gasoline
APPENDIX
(Nonmandatory Information)
X1. PERFORMANCE CHARACTERISTICS OF UNLEADED AVIATION GASOLINE
X1.1 Introduction
X1.1.1 Unleaded aviation gasoline is a complex mixture of relatively volatile hydrocarbons that v
...