Refinery Definitions FAQ
API Gravity - An arbitrary scale of the American Petroleum Institute for
measuring the density of oils.
Baume Gravity - A unit of measurement of specific gravity used in the chemical
industry. We use for caustic and acid.
A.S.T.M. DISTILLATION - The standard procedure of the American Society
for Testing Materials for determining the boiling range of petroleum distillates.
SPECIFIC GRAVITY - The ratio of the weight of a volume of a body to the
weight of an equal volume of some standard sub-stance. In the case of liquids
and solids, the standard is water; and in the case of gases, the standard is air.
VISCOSITY - A test to determine the internal friction or resistance to flow. It is
measured by the number of seconds required for a sample to pass through a
standard opening or orifice at a specified temperature.
REID VAPOR PRESSURE - A test that indicates the volatility of a liquid by
measuring the amount of pressure generated in a bomb at a specific temperature
COLOR-SAYBOLT - A test used for determining the color of gasoline and
burning oils - range from 30 for gasoline to -16 for furnace oils.
A.S.T.M. - UNION - A test for determining the color of furnace oils and heavier
products - range from 0 for clear oils to 10 for dark oils.
FLASH POINT - A test designed to determine the lowest temperature at which a
petroleum product forms vapor, under specified conditions, at a rate sufficient to
produce a momentary flash when a small flame is passed over it.
10. OCTANE NUMBER - A test to determine the anti-knock properties of a
gasoline sample. It is performed by burning a sample in a gasoline motor and
comparing its performance with reference fuels (iso-octane: 100 octane number
and normal heptane: 0 octane number). The octane is the percent of iso-octane in
a mixture of iso-octane and heptane that matches the performance of the sample.
11. POUR POINT - A test which determines the lowest temperature at which oil will
flow when chilled under prescribed conditions.