Oil analysis (OA) is the laboratory analysis of a
lubricant
A lubricant (sometimes shortened to lube) is a substance that helps to reduce friction between surfaces in mutual contact, which ultimately reduces the heat generated when the surfaces move. It may also have the function of transmitting forces, t ...
's properties, suspended contaminants, and wear debris. ''OA'' is performed during routine
predictive maintenance
Predictive maintenance techniques are designed to help determine the condition of in-service equipment in order to estimate when maintenance should be performed. This approach promises cost savings over routine or time-based preventive maintena ...
to provide meaningful and accurate information on lubricant and machine condition. By tracking oil analysis sample results over the life of a particular machine, trends can be established which can help eliminate costly repairs. The study of wear in machinery is called
tribology
Tribology is the science and engineering of interacting surfaces in relative Motion (physics), motion. It includes the study and application of the principles of friction, lubrication and wear. Tribology is highly interdisciplinary, drawing on m ...
. Tribologists often perform or interpret oil analysis data.
OA can be divided into three categories:
# analysis of oil properties including those of the base oil and its additives,
# analysis of contaminants,
# analysis of wear debris from machinery,
Oil sampling
Oil sampling is a procedure for collecting a volume of fluid from lubricated or hydraulic machinery for the purpose of oil analysis. Much like collecting forensic evidence at a crime scene, when collecting an oil sample, it is important to ensure that procedures are used to minimize disturbance of the sample during and after the sampling process. Oil samples are typically drawn into a small, clean bottle which is sealed and sent to a laboratory for analysis.
History
OA was first used after
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
by the US
railroad industry to monitor the health of locomotives. In 1946 the
Denver and Rio Grande Railroad
Denver () is a consolidated city and county, the capital, and most populous city of the U.S. state of Colorado. Its population was 715,522 at the 2020 census, a 19.22% increase since 2010. It is the 19th-most populous city in the United ...
's research laboratory successfully detected
diesel engine
The diesel engine, named after Rudolf Diesel, is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression; thus, the diesel engine is a so-call ...
problems through
wear
Wear is the damaging, gradual removal or deformation of material at solid surfaces. Causes of wear can be mechanical (e.g., erosion) or chemical (e.g., corrosion). The study of wear and related processes is referred to as tribology.
Wear in m ...
metal analysis of used oils. A key factor in their success was the development of the
spectrograph, an instrument which replaced several
wet chemical
Wet may refer to:
* Moisture, the condition of containing liquid or being covered or saturated in liquid
* Wetting (or wetness), a measure of how well a liquid sticks to a solid rather than forming a sphere on the surface
Wet or WET may also refe ...
methods for detecting and measuring individual
chemical element
A chemical element is a species of atoms that have a given number of protons in their nuclei, including the pure substance consisting only of that species. Unlike chemical compounds, chemical elements cannot be broken down into simpler sub ...
such as
iron
Iron () is a chemical element with symbol Fe (from la, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, right in f ...
or
copper
Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkis ...
. This practice was soon accepted and used extensively throughout the railroad industry.
By 1955 OA had matured to the point that the United States
Bureau of Naval Weapons The Bureau of Naval Weapons (BuWeps) was part of the United States Navy's material organization between 1959 and 1966, with responsibility for procurement and support of naval aircraft and aerial weapons, as well as shipboard and submarine naval we ...
began a major research program to adopt wear metal analysis for use in aircraft component failure prediction. These studies formed the basis for a
Joint Oil Analysis Program (JOAP) involving all branches of the U.S. Armed Forces. The JOAP results proved conclusively that increases in component wear could be confirmed by detecting corresponding increases in the wear metal content of the lubricating oil. In 1958
Pacific Intermountain Express (P.I.E.) was the first trucking company to set up an in-house used oil analysis laboratory to control vehicle maintenance costs which was managed by Bob Herguth. In 1960 the first independent commercial oil analysis laboratory was started by Edward Forgeron in
Oakland, CA
Oakland is the largest city and the county seat of Alameda County, California, United States. A major West Coast port, Oakland is the largest city in the East Bay region of the San Francisco Bay Area, the third largest city overall in the Bay ...
.
Standard practices
In addition to monitoring oil contamination and wear metals, modern usage of OA includes the analysis of the additives in oils to determine if an extended drain interval may be used. Maintenance costs can be reduced using OA to determine the remaining useful life of additives in the oil. By comparing the OA results of new and used oil, a tribologist can determine when an oil must be replaced. Careful analysis might even allow the oil to be "sweetened" to its original additive levels by either adding fresh oil or replenishing additives that were depleted.
Oil analysis professionals and analysts can get certified in compliance with ISO standards by passing exams administered by the International Council for Machinery Lubrication (ICML).
For purposes of Oil Analysis Program (OAP) trend analysis, replacement, replenishment or drain and flush of lubricating fluids in excess of half an engine’s oil capacity (2.5 gallons or more) will be considered an Oil Change and the engine will be placed in code Charlie (C) for three flights to establish a new working trend. Oil-Wetted Maintenance (OWM) is any replacement of engine components within an oil-lubricated system (bearings, gearbox, pumps, etc.). OWM actions shall be documented on DD Form 2026 and submitted to OAP lab for update of Oil Analysis database.
(a) Special Samples can be requested by the laboratory whenever they feel its necessary.
(b) Whenever directed by the unit maintenance activity to investigate suspected deficiencies.
The NDI/JOAP laboratory will set the standards and intervals of oil analysis.
A typical
predictive maintenance
Predictive maintenance techniques are designed to help determine the condition of in-service equipment in order to estimate when maintenance should be performed. This approach promises cost savings over routine or time-based preventive maintena ...
technique is
ferrography Ferrography is a specialized type of oil analysis used to study particle wear on machine components through analysis of contaminants in lubricating oil. It can be used to predict and diagnose errors occurring on machinery. Ferrography is related to ...
, which analyses iron in oil.
See also
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External links
Sampling Procedures for transformer Oil AnalysisIntroduction videos to lube oil analysisIntroduction Book to lube oil analysis practicesSociety of Tribologists and Lubrication EngineersCommon Properties tested through Oil AnalysisPracticing Oil Analysis magazineInternational Council for Machinery LubricationThe Basics of Used Oil SamplingIntroduction To benefits of oil sampling with a free cost saving calculator to calculate Return on Investment
Sampling Procedures Build Solid Foundation for Oil Analysis Success
Lubricants
Motor oils
Petroleum
Hydraulics
Engine lubrication systems