Machinery Lubrication May June 2014 May June 2014 | Page 32

analyzed but most often have a marginal
limit of approximately 10 percent and a

that is too low can indicate high engine

critical limit of approximately 20

blow-by conditions (fuel, soot, etc.),

percent higher or lower than the

the presence of an incorrect lubricant,

intended viscosity.

32%

or additive depletion. A base number

internal leakage contamination (glycol)
or oil oxidation from extended oil drain

of lubrication professionals
would not understand how to
interpret an oil analysis report
from a commercial laboratory,
based on a recent poll at
MachineryLubrication.com

Acid Number/Base Number

intervals and/or extreme heat.

Acid number and base number tests are
similar but are used to interpret
different lubricant and contaminant-

FTIR is a quick and sophisticated

related questions. In an oil analysis test,

Viscosity

FTIR
method for determining several oil

the acid number is the concentration of

parameters including contamination

Several methods are used to measure

acid in the oil, while the base number is

from fuel, water, glycol a