September 2022 - 20

feature | lubrication solutions
review oil-analysis data in reports and
write recommendations based on data
that is in alarm, or outside of the
alarm limits. Th ese analysts
understand the nuances of
laboratory test methods,
the alarm limits for those
tests and how they are
determined, how some
test data correlates to
other test data, characteristics
of diff erent
lubricant types/chemistries,
lubricationrelated
failure modes,
industrial equipment
applications, and lubrication
requirements.
Th ese are some of the
underlying competencies of an
analyst who reviews your oil-analysis
report. Th eir knowledge is wide and deep,
but it can only be applied within the context
of the data on the report. Ideally, this data
has been collected consistently over time
and trends have been established. Sometimes
this is not the case. Note that a single
oil-analysis report is a snapshot in time and
does not indicate trends and rates of change.
Also note that there are many operational
variables involved in lab test data. Without
an understanding of these variables, even
the best-trained and most-experienced
analyst will have only a partial picture with
which to assess data and determine machine
and lubricant condition.
WHAT A PLANT KNOWS
Th e plant staff , charged with operating and
maintaining assets, possess the contextual
information that make an oil-analysis report
data meaningful. Th is information includes
any activity performed on or related to the
equipment that might aff ect its operation
or the lubricant within it, including the
samples drawn from it.
20 | EFFICIENTPLANTMAG.COM
industry governing bodies. Most commercial
labs can implement custom static limits
according to customer request and can
provide guidance to that end. Among
common tests found in routine
oil-analysis test slates, static
limits are employed for viscosity,
particle count, and water
concentration.
Some common modern
viscosity standards are the
ISO (International Standards
Organization) 3448 standard
for industrial lubricants, and
SAE (Society of Automotive
Engineers) J300 for crankcase
(engine) oils, and SAE J306 for
gear oils (all measured in centistokes,
or cSt). Th ese standards
classify lubricants into " grades, " each of
which encompasses a range of viscosities
A lab analyst's knowledge is extensive, but it
can only be applied within the context of data
that has been collected consistently over time.
First and foremost, the plant team knows
precisely how and when samples are collected.
Th e quality of lubricant samples and
the consistency used to obtain them are the
primary determinants of the resulting data
reliability.
Second, lubricant top-off s, drains and
fi lls, changes to the lubricant product in use,
any mechanical maintenance, changes in
operational cycles, and potential introduction
of contaminants from nearby activity
are contextual factors that can aff ect lubricant-analysis
data.
ALARM LIMIT METHODOLOGIES
Broadly speaking, there are two types of
alarm limits: static and dynamic. Static
alarm limits do not change in value and are
based on fi xed characteristics. Th ey are
oſt en specifi ed by OEM requirements and
around a midpoint.
Th e ISO standard is +/-10% from that
midpoint. Oſt en an OEM will require an
ISO-grade lubricant, for example ISO 32.
In this case, the acceptable viscosity range
for a lubricant in this system is 32 +/-3.2,
or 28.8 to 35.2. Th erefore, the static alarm
limits are 35.21 (upper bound) and 28.79
(lower bound). Th ese are the marginal
alarm limits.
Critical alarm limits are most commonly
+/- 20% from the midpoint, or 38.41
(upper bound) and 25.59 (lower bound).
Th ese static limits will not change based on
trended data. Th e in-service fl uid is either
in or out of the OEM specifi cation of ISO 32
grade. More information about the SAE and
ISO standards is widely available.
Similarly, the alarm limits for the particle-count
test depend on the specifi c equipment
application, such as the component
clearances and fl uid pressure levels. Particle
count is measured by the ISO 4406 Standard
Cleanliness Code system, which is based on
the number of particles within specifi ed size
SEPTEMBER 2022
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September 2022

Table of Contents for the Digital Edition of September 2022

September 2022 - Cover1
September 2022 - Cover2
September 2022 - 1
September 2022 - 2
September 2022 - 3
September 2022 - 4
September 2022 - 5
September 2022 - 6
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September 2022 - Cover3
September 2022 - Cover4
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