Water Reaction of Aviation Fuels (ASTM D-1094).
Scope. This test method covers the determination of the presence of water-miscible components in aviation
gasoline and turbine fuels, and the effect of these components on the fuel-water interface.
Summary. A sample of fuel is shaken, using standardized technique, at room temperature with a phosphate
buffer solution. The change in volume of the aqueous layer, the appearance of the interface, and the degree of
separation of the two phases are taken as the water reaction of the fuel.
Significance. Water extraction of aviation fuels using this technique reveals the presence of relatively large
quantities of partially water soluble contaminants such as surfactants. Contamination that affect the interface or
create emulsions in the water or fuel layers are apt to disarm filter separators quickly and allow free water and
particulates to pass. A change in volume of the aqueous layer indicates that water soluble materials such as
alcohol or ethers are present.
Particulate Contaminant in Aviation Turbine Fuels (ASTM D-2276).
Scope. This test method describes a procedure for the evaluation of particulate contaminant in aviation turbine
fuels.
Summary. A known volume of fuel is filtered through a preweighed test membrane filter and the increase in
membrane filter weight determined after washing and drying. The total contaminant is determined from the
increase in weight of the test membrane filter relative to the control membrane filter.
Significance. This test method provides gravimetric measurements of the particulate matter present in aviation
turbine fuels, which must be minimized to avoid filter plugging and other operational problems.
Existent Gum in Fuels by Jet Evaporation (ASTM D-381).
Scope. This test method covers the determination of the existent gum in motor gasoline and aircraft fuels at the
time of the test.
Summary. A measured quantity of fuel is evaporated under controlled conditions of temperature and flow of air
or steam. For aviation gasoline and aircraft turbine fuel, the resulting residue is weighed and reported as
milligrams per 100 ml. for motor gasoline. The residue is weighed before and after extracting with n-heptane,
and the results are reported as milligrams per 100 ml.
Significance. The true significance of this test method for determining gum in motor gasoline is not firmly
established.
Water-Separation Characteristics - MICRO WSIM (ASTM D-3948).
Scope. This method provides a rapid portable means for field and laboratory use to rate the ability of aviation
turbine fuels to release entrained or emulsified water when passed through fiberglass coalescing material. It is
intended to measure the water-separation characteristics of fuel as produced, after it has been blended with
additives or delivered to the point of use.
Summary. The fuel sample is emulsified with water in a syringe using a high-speed mixer. The emulsion is then
expelled from the syringe at a programmed rate through a standard fiberglass coalescer, and the effluent is
analyzed for uncoalesced water by light transmission measurement. High ratings indicate the water is easily
coalesced and, therefore, that the fuel is relatively free of surfactant materials.
Significance. The test provides a measure of the presence of surface active substances in aviation turbine
fuels. It can detect carry-over of traces of refinery treating residues in fuel as produced. It can also detect surface
active substances added to or picked up by fuel during handling from point of production to point of use.
Fuel System Icing Inhibitor in Hydrocarbon Fuels - FSII (FTM 5327.4).
Scope. This method is used for determination of 0.05 to 0.20 volume percent ethylene glycol monomethyl ether
(EGME) and diethylene glycol monomethyl ether (DiGME) in hydrocarbon fuels.
Summary. Two compounds are approved as fuel system icing inhibitors (FSII) in hydrocarbon fuels. In this
method, FSII will denote EGME or DiGME. The test consists of removing the FSII from the hydrocarbon fuel by
extraction with water. The water solution is allowed to react with an excess of standard potassium dichromate
solution in the presence of sulfuric acid, and the excess dichromate is determined iodometrically.
Significance. FSII is an additive in aviation turbine fuel that prevents dissolved water from freezing at high
altitudes (above 8,500 feet). If the FSII % by volume is too low: DETERIORATION (loss of additive) due to
CONTAMINATION with water.
3-5
QM 5184
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