Use fluid analysis to detect problems before they become failures

Managing effective fluid analysis yields a return on your investment.

By Mark Minges

When effectively managed, fluid analysis is an informative, diagnostic tool that can reduce maintenance costs, increase productivity and boost profits for any manufacturer. Used alone or in conjunction with other diagnostic technologies, fluid analysis can detect a variety of problems before they become failures, which are far more costly than repairs. When used to affect change in everyday maintenance practices, fluid analysis justifies itself by documenting what it saves in repair and replacement costs, as well as promotes relevant, well-informed maintenance management decisions.

Once you decide to adopt fluid analysis, several considerations are necessary for implementing and maintaining an effective program. These range from setting realistic program goals to selecting a quality laboratory. Planning is key. Fluid analysis places a wealth of information at your fingertips about the condition of your equipment and its fluids. But it's worth nothing if you can't maximize its value with a positive impact on your bottom line. It's not just fluid analysis — it's what you do with it that determines the ROI.

Set attainable goals

Goals are the yardstick by which you can measure the success of your program. Carefully examine your current maintenance practices and strategies, and determine whether they're helping you accomplish your goals. How are you measuring that accomplishment? Document any equipment saves you can credit to fluid analysis. Documenting increased uptime, reduced fluid consumption and less frequent parts replacement allows you to justify the cost of doing fluid analysis.

The size of your program determines the number of people necessary to maintain it and indicates whether fluid analysis becomes someone's sole responsibility or only a portion of the job. Identify who will be pulling samples and who will be managing the data.

Samplers typically are the technicians responsible for changing fluids and filters changes and other routine maintenance. Train them on the installation and use of the sampling devices and methods you've chosen, as well as proper documentation for the sample information the laboratory needs. Data managers need an Internet-enabled computer, good computer skills and an understanding of databases. They also should be given extensive training on the fluid analysis data management software programs you intend to use.

Select testing that supports your program goals. If you simply want to monitor the condition of the unit and the fluid, basic testing for wear and contamination will suffice. Testing total acid number and oxidation/nitration is vital to extending drain intervals. Particulate analysis by particle quantifier (PQ), ISO particle count or analytical ferrography and micropatch all help monitor the size, count and distribution of ferrous wear particles and can identify the source, which allows you to predict and prevent catastrophic failure.

Sampling frequencies

Although an equipment manufacturer's recommendations provide a good starting point for developing preventive maintenance practices, sampling intervals can easily vary. Criticality to production is the most important factor in determining which units or components you test and how often.

Extreme operating conditions also are important sampling considerations. Dirt, system debris and water tend to separate from the oil when system temperatures cool. Representative samples require sampling be done while the system is operating or immediately after shutdown.

Timing is critical

Trend analysis works best when sampling intervals are consistent and samples are shipped immediately. Maintenance personnel responsible for sampling should be well trained — and re-trained when necessary — on the appropriate sampling point(s), frequency and designated method for each piece of equipment being tested. For proper trend analysis, hydraulics, gear systems and pumps should be sampled quarterly at minimum.

Take samples from either a vacuum pump through the fill port or from a permanently installed petcock. Be sure to flush at least five times the volume of any dead space before catching the sample. If a drain plug is the only way to catch a sample, be sure to allow five times the volume of the sample container to flow before catching the sample. Use a separate container to collect the forerunning oil to avoid contaminating the clean sample container.

Know the equipment, share the knowledge

Accurate, thorough and complete fluid and equipment information allows for better, in-depth analysis and increases the value of a data analyst's comments and recommendations. Give your laboratory the most current, accurate equipment identification information, including make, model, application, filter types and micron ratings, sump capacity, operating hours on both the unit and the fluid and whether the fluid has been changed. Consult every resource available to you; procurement records, inventory databases and OEM service manuals are good places to start. After the laboratory has the information, request a copy to verify the accuracy and promptly communicate any needed changes.

Every laboratory's system for managing sample information is unique, but all of them rely on the information you submit with the sample to set alarm and severity limits. Missing or inaccurate information limits data interpretation.

Take an active role in minimizing sample turnaround time. Don't let unidentified bottlenecks in turnaround time degrade the value of fluid analysis results and recommendations. Ensure sample label information is accurate and complete. Clearly identify any special instructions.

Use a trackable mail service for sending samples to the laboratory but demand to receive your results electronically. Understand that laboratory turnaround time begins when the sample is received and ends when results have been sent to the user. Therefore, 24-hour turnaround means it takes 24 hours from receipt of the sample by the laboratory to log it, test it, analyze the results and send a report.

Review reports, take action

When reviewing your most negative reports, consider the results in light of other available diagnostic information such as vibration analysis, thermography and in-line sensors. Either act on the analyst's recommendations or order more testing. If re-sampling is recommended, immediately sample again or at half the normal interval to verify results. Otherwise, closely monitor the unit and sample again at the normal interval.

Cautionary reports might flag some wear and contamination results, although those results don't necessarily indicate a particular failure mode or are significant enough to warrant action. Retain them for later reference as more data is collected on subsequent samples — trends will be easier to spot and the appropriate action to take clearer. Review normal reports as time permits. Knowing where you started helps in recognizing trends when reviewing historical data.

Manage the data

The size of your operation and ambition of your goals and resources dictate the best and most efficient means for receiving and managing test data. Web-based applications should have data management reporting capability such as problem summaries, sampling frequencies and turnaround tracking.

Personal data management software applications should be able to import data, build data management reports, customize graphs, and perform statistical analyses and correlation studies. PC-based programs often are the best option for programs that sample hundreds to thousands of pieces of equipment across multiple locations.

Continually monitor fluid analysis communication channels. Have a system in place that allows you to take action. Failing to do so might not only lead to unnecessary failure or downtime but drastically reduce the value of your fluid analysis dollar. Fluid analysis effectiveness is best measured when the maintenance you perform can be correlated to fluid analysis recommendations. Your laboratory should be able to document your feedback on maintenance or diagnostics performed and use it to improve its flagging and severity protocols.

Choose a laboratory with your program expectations in mind. Expect quality results, which means they're repeatable, reproducible and have validated degrees of uncertainty.


Initial evaluation

In deciding if a fluid analysis laboratory is right for you, ask yourself the following:
  • Can it meet all my program's requirements?
  • Can it perform the testing in an appropriate amount of time?
  • Can I call any laboratory location with questions, or am I limited to just the one to which we sent the sample?
  • How does the laboratory ensure consistency from location to location?
  • Will I always be able to speak with an analyst
  • Is training available to ensure everyone involved is on the same page?


ISO 17025 is the international standard for testing and calibration laboratories. A laboratory's compliance with ISO 17025 that is accredited by the American Association for Laboratory Accreditation (A2LA) represents the highest level of quality attainable by a testing laboratory. Dedicated to formally recognizing competent testing and calibration laboratories, A2LA is the most stringent accrediting body in the industry. Although price is always a factor, quality results, good turnaround and open lines of communication are essential to both a good relationship with your laboratory and to realizing a return on your fluid analysis investment.

Mark Minges is chief operating officer at Polaris Laboratories, Indianapolis. E-mail him at