Oil Analysis | What Is Oil Analysis?

Oil Analysis

What is oil analysis?

Oil analysis is the analysis of a lubricant’s properties, composition, and contaminants. It is a routine activity used to determine the health of oil and the machinery in which it is used. Think of it as a blood test for machinery.


Over 70% of equipment failure is attributed to surface degradation related to oil contamination. Oil analysis is one of the most simple ways to to monitor contamination proactively. When implemented effectively, an oil analysis program reduces uncertainty, risk, and reactive work for a maintenance department. It is used as a tool for predictive maintenance.

Like all other predictive maintenance tools, oil analysis benefits a maintenance department by:

  1. Saving money through predicting and preventing damage
  2. Increasing confidence in equipment reliability
  3. Reducing equipment downtime and increasing uptime and production
  4. Enabling scheduled maintenance and decreasing potential for unplanned repairs

Oil analysis can provide a detailed view of what is happening inside machine components. An effective oil analysis program requires planning to address the following areas:

  1. Equipment selection
  2. Sampling method development
  3. Primary and secondary test slate selection
  4. Alarm specifications development
  5. Data review, evaluation, and corrective action

Types of oil analysis tools

Extensive knowledge and experience are required from personnel involved in oil analysis and interpretation of testing results. Any time components fail, those who performed the analyses should be included in the investigation process. Familiarity with the needs of your industry and equipment specifications will determine what tools and/or resources your organization should use for oil analysis.

Examples of resources that can be employed in an oil analysis program are listed below, along with advantages and disadvantages of each:

Resource Advantages Disadvantages
Commercial Testing Lab

Employs highly qualified experts

Well equipped with efficient and precise instrumentation

Poor control of sampling methodology

Analysts may have limited ability to interpret skills

In-House Testing Lab

Analysts and maintenance crew all under one roof if not same people

Less sample handling means better control of sample integrity

Cost of additional in-house operations

Budget restrictions may not allow purchase of most efficient and precise testing equipment

Mobile Oil Lab Allows for onsite testing which limits sample handling and avoids need for capital expenditure Allows for onsite testing which limits sample handling and avoids need for capital expenditure
Continuous Monitoring Technology

Ability to provide data during the entire operation cycle

Some highly sophisticated sensors allow for real-time monitoring and decision making

Additional infrastructure needed to support large amounts of data

Additional maintenance needed for monitoring the technology itself

Portable Analysis Tools

Saves time through onsite testing, ease of use, and portability

Cost effective

Quicker results mean quicker response times when needed

As with any new technology, its success depends on the user’s ability to understand it

How to use oil analysis for predictive maintenance

Predictive maintenance is an integral part of a company’s asset management strategy. It is considered to be the most advanced type of maintenance available. This type of maintenance aims to evaluate the condition of in-service equipment to estimate when maintenance should be performed. Oil analysis is just one of several types of predictive maintenance.

As previously stated, a significant amount of equipment failure has been found to be related to oil contamination.

Oil analysis can be used to determine the following:

  1. Fluid properties: Evaluates condition of the lubricant which could affect oil change intervals
  2. Wear metal analysis: Surface wear is considered to be the predominant threat to long-term equipment performance. Machine condition can be evaluated by measuring debris in oil
  3. Contamination: Different types of contamination can affect equipment in different ways. For example, presence of air and water may affect fluid film required for surface separation. Presence of atmospheric and process chemicals can cause surface abrasion.

Although we have defined oil analysis as a means of predictive maintenance thus far, it can also be used as a tool to verify the effectiveness of a shop’s lubrication activities.

Example of oil analysis

Oil analysis programs are designed to to provide information about the state of the oil and condition of the machine. There is a wide array of testing used to deliver this type of information. The following are specific examples of how fluid properties, machine wear, and contamination can be tested.

  1. Particle counting (PC) is a tool for determining overall cleanliness and contamination in used oil.
  2. Viscosity is the most important property of a lubricant; it is what allows it to form the protective layer required for separating moving surfaces.
  3. Spectroscropy helps monitor contaminant metals and enables analysts to look for species of molecules that don’t belong in the oil.
  4. Water content, which, as the name suggests, measures presence of water. Water is a common contaminant that has potentially devastating effects including rust, increased wear rate, and loss of additive functionality.
  5. Neutralization number measures a change in the concentration of acid in an oil which is indicative of oxidation, corrosion, or depletion of additive levels.

Can you benefit from oil analysis?

Predictive maintenance is the most advanced type of maintenance currently available. As with anything new and innovative, it’s easy to list both the beneficial and disruptive effects of implementing an oil analysis program.

A properly executed program development process is key in identifying both the pros and cons of an oil analysis program from the beginning.

The program development process should answer the following questions:

  1. Which pieces of machinery should be monitored? What are the criteria used during the selection process?
  2. Who is responsible for oil sampling? What controls are in place to ensure cleanliness and consistency during sampling?
  3. What properties of the oil should be monitored? Is there a proper understanding of why each should be measured?
  4. How will your organization properly document information and develop personnel to identify and address failing criterion?
  5. How will this impact workload, equipment, and costs?
  6. How will we measure the effects (success or failure) of this program? What processes and roles have your management team created to assure understanding of data and how it should be used?

Lastly, a company’s oil analysis program is only as good as its personnel’s ability to understand and appropriately respond to the data that will be produced. Decisions must be made to improve the long-term effectiveness of equipment.

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