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d. This is one o
ty of RPVOT te
bine Oil
Y B R I E F
n is more com
ing concern by
sults when it
s turbine oils
which impact
n of the test in
ent in the AST
of 12% and a
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roducibility of th
tween 30-50%
ational standa
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t with some ty
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is run on mo
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reproducibility
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e amount of tim
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e proper determ
ASTM stipulate
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n in Oil 2 ver
retation of the
g life after the
st, Point B or P
ting factors to
ations
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odern lubrican
ex, synergistic
on of RPVOT
es compared to
(ASTM D2272
of 22% for oils
y speaking, the
erally accepted
onducted mini-
reported 39%
eatability and
ch more difficul
determining an
e oils. RPVOT
me required to
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mination of the
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FLUITEC INTERNATIONAL | www.fluitec.com
Turbine Oil Oxidation Research
Test Start of
Test Value
End of
Test Value
Comments
Viscosity (cSt @ 40C) ASTM D‐445M
31.7 32.1 Insignificant. Within Test Reproducibility.
Acid Number (mg KOH/g) ASTM D‐664M
0.10 0.11 Insignificant. Within Test Reproducibility.
RPVOT (mins) ASTM D‐2272
945 900 Insignificant. Within Test Reproducibility.
Membrane Patch Colorimetry Draft ASTM Standard
2 57 Very Significant. Indicates high varnish potential.
RULER™ – Amines (% of new)
ASTM D‐6971
100% 91% Significant. Close relationship to RPVOT values.
RULER™ – Phenols (% of new)
ASTM D‐6971
100% 17% Significant. MPC increases as Phenols deplete.
0102030405060708090100
-15%
-10%
-5%
0%
5%
10%
15%
1 2 3 4 5 6 7 8
ViscosityANRPVOTMPCAminesPhenols
Summary of Oxidation Experiment
The results of the experiment show that Viscosity, Acid Number
and RPVOT show little change over the course of the 8-week
experiment. However, there is a clear change in looking at the
RULER results which measures the amine and phenol
antioxidants. There is also a significant rise in the Membrane
Patch Colorimetry test, which is measuring the accumulation of
oil oxidation products. The summary of the experiment
demonstrate the effectiveness in monitoring individual
antioxidants in aged turbine oils and some of the challenges in
using RPVOT and other testing methodologies. The experiment
also illustrates the value in running RULER™ testing along with
MPC testing.
MPC Patch at End of Test
RPVOT: 1850
Very high varnish potential.
MPC Patch at End of Test
RPVOT: 217
Very low varnish potential.
Understanding How Turbine Oils Degrade
Oil analysis has been the primary tool to detect incipient lubricant
failure for the last half century. The first step however in
determining an appropriate test slate for turbine oil is
understanding its mode of failure. Fluitec personnel were part of
a research project during which five turbine oils were circulated in
immersion heated baths at 120oC for 8 weeks (ASTM Paper
JAI100465). A wide range of analytical tests were performed in
order to better understand which specific testing methodologies
would provide the highest value for detecting early signs of
turbine oil degradation and the associated by-products which
negatively impact lubrication systems. Below is a summary of
results averaged from all 5 samples over the 8 week test.
MPC, Amines & Phenols are plotted on the right hand axis.
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