Machinery Lubrication May June 2014 May June 2014 | Page 36

report presents previously identified

additional viscosity measurements will

from past analysis. The acid number

sample information from the customer

be identified. The viscosity for engine

often will jump considerably at some

such as oil manufacturer, brand,

crankcase oils is typically reported at

point. This may be your best indicator

viscosity grade and in-service time, as

100 degrees C.

for when the oil is oxidizing rapidly and

well as if an oil change has been

should be changed.

performed. This is important data that

Water contamination, which commonly

can provide an explanation for what

is measured by the Karl Fischer test, is

The last section of the oil analysis report

could be false positives in alarming

presented in percentages or ppm. While

generally provides written results for

data changes.

some systems are expected to have high

each of the final few test samples along

levels of water (more than 10,000 ppm

with recommendations for required

The “physical tests” section of a report

or 10 percent), the typical alarm limits

actions.

offers details on viscosity at both 40

for most equipment are between 50 to

recommendations are entered manually

degrees C and 100 degrees C, along

300 ppm.

by laboratory personnel and based on

with the viscosity index and percentage

Typically,

these

information provided by the customer

of water. For common industrial oils,

The “additional tests” section shows

and the data collected in the lab. If

the viscosity measurement at 40 degrees

two final tests: acid number (AN) and

there is an explanation for the data that

C is usually given, since this correlates

particle size distribution (aka, particle

stems from something not explicitly

to the oil’s ISO viscosity grade. If the

count). When analyzing the acid

stated by the customer, the results must

viscosity index must also be calculated,

number, you should have both a

be reinterpreted by those familiar with

such as for engine oil, then these

reference value and the ability to trend

the machine’s history of environmental

Graphs in an oil analysis report can help illustrate notable trends in the data. (Ref. Fluid Life)

34| May-June 2014 | www.machinerylubricationindia.com

www.machinerylubrication.com

|

November - December 2013

| 34