PART A QUALITY SURVEILLANCE TESTING
Quality surveillance for you as a senior laboratory NCO, will involve having thorough knowledge of all visual and
analytical testing methods, as well as the causes and indications of contamination.
Fibrous Material. When looking at a clear quart glass container, fibrous material will appear as pieces of
thread-like material, similar to fiberglass threads, suspended in the product or lying at the bottom of the
container.
Sediment. This will appear as dust, powder, flakes, and/or granular material. Total sediment includes both
organic and inorganic material. You may categorize sediment either as coarse or fine.
Coarse sediment. Sediment which easily settles out of the product or can be removed by filtration.
Ordinarily, "coarse sediment" refers to particles of 10 mn (micron) size or larger. This type of sediment
is quite visible in a clear glass container.
Fine sediment. Sediment that is smaller than 10 microns. To a limited degree, this type of sediment can
be removed by settling or filtration. Fine particles are not visible to the naked eye as separate or distinct
particles. However, the particles will scatter light and may appear as pinpoint flashes of light (like the
shimmer of a diamond) or as a slight haze in a sample.
Microbiological Growth. This growth consists of living organisms that grow at the fuel-water interface.
These organisms include protozoa, fungus, and bacteria, and they normally have a brown, black, or gray color in
addition to a stringy, fibrous-like appearance when observed in a clear glass container. Removal of water
bottoms will prevent this problem.
Water. Water in fuels may be either fresh or salty and may be present as either dissolved, entrained, or free
water.
Dissolved water. This is water that has been absorbed by the fuel and is not visible during sample
inspections at ambient temperature. When the fuel is cooled, dissolved water becomes entrained and
appears as a cloud. Dissolved water is only fresh water and cannot be removed except by freezing.
Fuel system icing inhibitor (FSII) is added to jet fuels to prevent dissolved water from freezing.
Entrained water. This is an emulsion of water in fuel and is visible as a cloud. Entrained water can be
removed by filtration.
Free water. This is water that may appear in the form of a cloud, emulsion, emulsion droplets, or in
larger amounts in the bottom of a tank or other container. Free water is normally readily detectable
during visual sample inspections and settles out in storage within 24 hours.
Commingling. Commingling is the accidental mixing of products that usually occurs when too much interface
mixture is pumped into the storage tanks. Upon settling, the contaminants will usually stratify into layers in the
tank.
PART B TESTING PROCEDURES
API Gravity Test (ASTM D-287).
Scope. This test method covers the determination by means of a glass hydrometer of the API gravity of crude
petroleum and petroleum products normally handled as liquids and having a Reid vapor pressure of 26 psi or
less.
Summary of Test. The API gravity is read by observing the freely floating API hydrometer and noting the
graduation nearest to the apparent intersection of the horizontal plane surface of the liquid with the vertical scale
of the hydrometer and observing the temperature of the sample.
Significance of Test. Accurate determination of gravity of petroleum and its products is necessary for the
conversion of measured volumes to volumes at the standard temperature of 60 degrees Fahrenheit. Also gravity
is a factor governing the quality of crude oils. However, the gravity of a petroleum product is an uncertain
indication of its quality.
QM 5184
3-2
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