ASTM D7960 Standard Specification for Unleaded Aviation Gasoline Test Fuel Containing a Non-hydrocarbon Component
4. General
4.1 This specification, unless otherwise provided, prescribes the required properties of unleaded aviation gasoline test fuel at the time and place of delivery.
5. Classification
5.1 One grade of unleaded aviation gasoline is described, UL102 aviation gasoline test fuel.
NOTE 1 - The above grade name is based on the fuel's motor octane as measured by Test Method D2700.
6. Materials and Manufacture
6.1 D7960 test fuel, except as otherwise specified in this specification, shall consist of blends of refined hydrocarbons derived from crude petroleum, natural gasoline, biomass or blends thereof, with synthetic hydrocarbons or aromatic hydrocarbons, or both; with hetero-molecules such as amines, alcohols, carboxylic acids, esters and ethers.
6.1.1 See Appendix X1 for a representative composition that meets the parameters of Table 1.
6.2 Additives - These may be added to D7960 test fuel in the amount and of the composition specified in the following list of approved materials:
6.2.1 Other Additives - These may be added 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.
6.2.1.1 Antioxidants - The following oxidation inhibitors may be added to the fuel separately, or in combination, in total concentration not to exceed 12 mg of inhibitor (not including mass of solvent) per liter of fuel.
(1) 2,6-ditertiary butyl-4-methylphenol.
(2) 2,4-dimethyl-6-tertiary butylphenol.
(3) 2,6-ditertiary butylphenol.
(4) 75 % minimum 2,6-ditertiary butylphenol plus 25 % maximum mixed tertiary and tritertiary butylphenols.
(5) 75 % minimum di- and tri-isopropyl phenols plus 25 % maximum di- and tri-tertiary butylphenols.
(6) 72 % minimum 2,4-dimethyl-6-tertiary butylphenol plus 28 % maximum monomethyl and dimethyl tertiary butylphenols.
(7) N,N'-di-isopropyl-para-phenylenediamine.
(8) N,N'-di-secondary-butyl-para-phenylenediamine.
6.2.1.2 Fuel System Icing Inhibitor (FSII) - One of the following may be used:
(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) may reduce knock ratings below minimum specification values.
(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 % to 0.15 % by volume when required by the aircraft owner/operator.
6.2.1.3 Corrosion Inhibitor Additive - Corrosion inhibitors that conform to the latest issue of MIL-PRF-25017 may be added to the D7960 test fuel in amounts not exceeding the maximum allowable concentrations listed in the latest revision of QPL-25017.
7. Detailed Requirements
7.1 The D7960 test fuel shall conform to the requirements prescribed in Table 1.
7.2 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.
8. Workmanship, Finish, and Appearance
8.1 The D7960 test fuel specified in this specification shall be free from undissolved water, sediment, and suspended matter. No substances of known dangerous toxicity under usual conditions of handling and use shall be present except as permitted in this specification.
9. Sampling
9.1 Because of the importance of proper sampling procedures in establishing fuel quality, use the appropriate procedures in Practice D4057 or Practice D4177.
9.1.1 Although automatic sampling following Practice D4177 may be useful in certain situations, initial manufacturer/supplier specification compliance testing shall be performed on a sample taken following procedures in Practice D4057.
9.2 A number of D7960 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.
