Tagged: used oil analysis

Lubricant Degradation / Oil Properties / Reliability / Storage & Handling of Lubricants / Used Oil Analysis

Role of Condition Monitoring, Human & Organizational Factors in Oil Failures

Choosing the right oil for the system is just one part of the puzzle. How do we know the oil is performing when it’s in the system? This is where condition monitoring can work hand in hand to help ensure that the oil does not fail the asset.

If a proper oil analysis program does not exist, operators will not know whether the oil is properly lubricating the asset. They will also not be aware of whether the oil is breaking down too quickly and failing to protect the asset. Oil analysis can also alert operators to signs of wear in the asset, so they can fix them before they turn into functional failures.

An oil analysis program that lives in a drawer protects assets about as well as no program at all.

There is also the possibility that an oil analysis program exists but is not top of mind, or that its results are put in a drawer. This can also cause the asset to fail even though the correct oil is being used. Apart from the aforementioned factors, if operators are not warned of the impending failure of the oil, this can result in production losses, increased downtime, and, in some extreme cases, the complete loss of the asset if it has failed beyond repair.

Incorrect sampling is another area in which the actual condition of the asset is not reported. Even with the correct oil used, if a sample is collected from a dead leg or an area that is not truly representative of the conditions inside the component, its actual condition will not be known. With incorrect data about the component, the asset can be misdiagnosed or treated for symptoms that do not exist, which can lead to its detriment.

Human and Organizational Factors

Not all failures occur at the equipment level; human and organizational factors can also cause the asset to fail even when the correct oil is used. If humans aren’t properly trained in oil sampling techniques or storage and handling practices, these can affect the asset’s functionality. We often forget that, at the heart of it all, lies the human factor, which is partially governed by the organization’s systems.

Training needs are an organizational factor that is often overlooked when considering how an asset can fail. However, if operators have not been trained in condition monitoring techniques, they will not be able to read oil analysis reports or take appropriate actions to protect the asset. Training can help bridge some competency gaps that directly impact asset performance.

It doesn’t matter what oil is in the system if no one is trained to monitor it – or motivated to care.

Culture is another factor swept under the rug. If the culture doesn’t exist to look after the assets, it doesn’t matter what type of oil is placed in the system; the asset will fail eventually. The performance of the asset does not only rely on using the correct oil. By implementing a culture of Asset ownership, where operators look after the asset and are accountable for its performance, assets are optimized to provide the functionality they should. This is one way to ensure the right oil is used to enable the assets’ performance.

Another area of concern is the documentation of maintenance procedures. If maintenance procedures are not adequately documented, someone new to the operation may not be aware of the correct practice. This, coupled with a lack of training, can spell disaster for the equipment. In these cases, even though the right oil was selected, the wrong practice or lack thereof can fail the asset.

Turning the “Right oil” into the “Right Outcome.”

As explained in this article, improper practices can jeopardize the asset’s health, even when the right oil is used. However, if all the right things align, we can have an asset that lasts for its expected lifetime or beyond.

This starts with selecting the right oil based on the application, environmental conditions, and OEM recommendations. If we follow this up with good storage and handling practices, proper condition-monitoring programs, documentation, and training, we can look toward a longer-lasting asset. The right oil enables reliability – but only disciplined practices deliver it.

Find out more in the full article, "When 'Right oil, Wrong practice' still fails assets" featured in Precision Lubrication Magazine by Sanya Mathura, CEO & Founder of Strategic Reliability Solutions Ltd. 

by
February 22, 2026
Lubricant Degradation / Oil Properties / Reliability / Storage & Handling of Lubricants / Used Oil Analysis

Common Modes of Failure for Lubricants

Regardless of the oil selected, common modes of failure can occur with every lubricant. These include: contamination, improper storage and handling practices, and environmental factors as shown in Figure 4.

Figure 4: Common modes of failure for lubricants
Figure 4: Common modes of failure for lubricants

Contamination can be defined as any foreign particle entering the system. This includes any gases, liquids, or solids. Especially when the lubricant system runs alongside the process side, process gases and liquids can leak into the oil. These contaminants can influence the oil’s degradation, leading to deposits or chemical reactions that break it down. Common process contaminants include ammonia or treated water.

The biggest threat to the right oil is often what gets added to it – whether it’s process contamination or the wrong oil during a top-up.

Another liquid that can contaminate oil is another oil. During top-ups, operators can add the wrong oil to the system, causing contamination and, depending on the oil, a possible shutdown. Adding motor oil to hydraulic oil can be catastrophic, as the additive packages work differently and the motor oil additives may counteract the hydraulic additives, removing them from the oil, leaving the asset open to wear and failure. Despite selecting the correct lubricant for your system, adding the wrong oil (mistakenly) will shorten its lifecycle and cause the asset to fail.

Bad storage and handling practices can also erode your oil, regardless of the oil you choose. Turbine and hydraulic oils are used in precise equipment. As such, they need to be clean and free of dirt or other contaminants. However, if oils are not stored correctly, contaminants can enter and contaminate the oil.

Simple techniques, such as transferring oil from larger storage containers (pails, drums, or totes) into smaller, more manageable containers (2-3 liters or less), can introduce contaminants into the oil if not done correctly. If oils are to be transferred to another storage container, the storage container must be clean. The transfer process should use clean hoses (not previously used for another lubricant) and be completed in a dust-free environment.

If you wouldn’t use a dirty needle for a blood transfusion, why would you use a dirty hose for an oil transfer?

The transfer of oils from one container to the next can be thought of as a blood transfusion. Would you use dirty needles or vials to transport the blood to be placed into another human? Similarly, oil can be likened to the equipment’s lifeblood and should be treated accordingly. Just as we observe sterile practices for blood transfusions, we should also observe similar types of practices for oil transfers.

Environmental and operational factors can also influence lubricant degradation. As stated earlier, all lubricants can degrade over time under harsh conditions. The lubricant formulation largely influences this, as does whether it was blended to withstand those conditions.

Oxidation can easily occur when temperatures increase, free radicals are present, or when wear metals are present. Thermal degradation occurs when the temperatures exceed 200°C. On the other hand, microdieseling occurs in the presence of entrained air, despite the lubricant used in the system, as shown in Figure 5.

Figure 5: Lubricant Degradation Processes
Figure 5: Lubricant Degradation Processes

Any of these degradation mechanisms can occur regardless of the type of oil chosen. Hence, it is essential to remember that operational conditions and environmental factors can heavily influence oil degradation, even when the oil is appropriate for the system.

Find out more in the full article, "When 'Right oil, Wrong practice' still fails assets" featured in Precision Lubrication Magazine by Sanya Mathura, CEO & Founder of Strategic Reliability Solutions Ltd. 

by
February 22, 2026
Oil Properties / Reliability

Spec Sheet vs Strategy for choosing the right oil

Sometimes we can spend hours poring over technical data sheets, comparing oil performances, and finally selecting the “right” oil which aligns with the needs of our equipment. Then, within 2 months, the oil degrades, our machines shut down, and we have a bunch of maintenance repairs lined up. What went wrong? We clearly had the “right” oil in the equipment; everything should have worked beautifully. This is where the awareness of lubrication and its practices becomes critical.

Having the correct oil is only one part of the puzzle. Being able to deliver that oil in its purest, cleanest form to the machine is often one of the other pieces that go missing. Another piece is selecting the right oil, not just based on the sales guy’s advice, but on the actual operating conditions of your machine. In this article, we dive a bit deeper into ways you can align the right oil with the proper practices, or avoid the wrong ones, to help extend the life of your asset.

Spec Sheet vs Strategy

For this example, we will consider a turbine oil selection. If a customer wants to change the oil in their turbine, then they may consider the following:

  • What are the OEM specifications that need to be met?
  • Is this oil available from the local supplier?
  • How does it compare to other oils on the market?
  • Does the cost justify the value? (or will the purchasing department want something cheaper?

For most of these questions, engineers or the person tasked with selecting the oil can readily find the answers in the oil’s technical data sheet and by talking to their sales representative. But if we dive a bit deeper, are we selecting the right oil for the operating and environmental conditions? Let’s examine the selection of a turbine oil for the Siemens SGT 200 Gas turbine that meets the Siemens TLV 9013 04 specification.

As seen in this document from Shell Lubricants, a few of their products meet that specification, namely Shell Turbo T, Turbo S2GX, Turbo S4X & Turbo S4GX.

Figure 1: Shell Turbo Family for the Siemens TLV 9013 04 Specification
Figure 1: Shell Turbo Family for the Siemens TLV 9013 04 Specification

On the other hand, Mobil provides some solutions as well, namely, Mobil DTE 732, 746, or DTE 832, 846

Figure 2: Mobil DTE 700 & 800 Series meeting the Siemens TLV 9013 04 Specification
Figure 2: Mobil DTE 700 & 800 Series meeting the Siemens TLV 9013 04 Specification

Chevron also provides an option of Chevron GST as follows:

Figure 3: Chevron GST oil meeting the Siemens TLV 9013 04 specification
Figure 3: Chevron GST oil meeting the Siemens TLV 9013 04 specification

With so many options, how can one choose the “right” oil? They all meet the required Siemens specification, TLV 9013 04. This is where the data sheets, OEM manual, and knowledge of the equipment’s operating conditions play a crucial role.

As per the manual, there are preset conditions for temperatures and pressures, but if your actual system runs hotter (or production is being pushed a bit more), it is functioning outside the operating envelope.

The spec sheet tells you what the oil can do. Your operating conditions tell you what it must do.

Additionally, if your surroundings are harsh (close to the sea or in a corrosive environment, or in a non-ventilated area where heat can build up), these can place additional stress on the equipment. For these harsher conditions, a synthetic oil might be more appropriate than a mineral oil, albeit more expensive in terms of the initial investment.

The manual also specifies which tests/characteristics should be used to monitor the condition of the oil, namely: viscosity, particle count, water content, demulsibility, air release, foaming characteristics, RULER®, and MPC. Based on the performance of your current oil in the system, you can determine whether these values fluctuate toward the higher warning zones. This can also influence your decision about which oil to choose.

It’s not just about the right oil or one that aligns with OEM requirements. The selection should also be based on the environmental conditions of the oil and the equipment, and on whether the oil is suited to perform in these conditions. A mineral oil will not withstand the temperatures that a synthetic oil can for extended periods without degrading. Similarly, given the “right” conditions, synthetic oils can also degrade. By cross-examining your spec sheet, OEM manual, and actual conditions, you can determine the best-suited oil for your operations.

Find out more in the full article, "When 'Right oil, Wrong practice' still fails assets" featured in Precision Lubrication Magazine by Sanya Mathura, CEO & Founder of Strategic Reliability Solutions Ltd. 

by
February 22, 2026
Oil Properties / Used Oil Analysis

How to identify the Root Causes of ESD in Lubrication

Thus far, all the prevention methods have focused on the physical roots of ESD. We did not explore some of the human or systemic roots that are also accountable for ESD. In this section, we will develop a logic tree designed to address a critical failure occurring in a plant. This will be used as an example of the logic tree, which can be developed when investigating the root causes of ESD.

Let’s start with the top of the logic tree, where we define the event or the reason we care. In this situation, it is an unplanned shutdown for 4 hours. An unplanned shutdown will impact the plant’s production, which is why we care about conducting this investigation.

We will assume that the failure mode occurred on one of the critical pumps, and we are investigating how that failure could have happened. Note, we did not ask the question “Why?” because it can be misleading to an opinion, and we are trying to stay as factual as possible.

A disciplined root cause analysis doesn’t start with ‘why’ – it starts with evidence. Each degradation mechanism tells its own story, and Electrostatic Spark Discharge is just one of them.

For this investigation, we will investigate the hypothesis of a critical bearing failing due to lubricant degradation. Since we are focused on ESD for this article, we will have only one hypothesis regarding the degradation mode being ESD. However, in the real world, if this logic tree were being developed, we would be investigating the six various lubricant degradation mechanisms: oxidation, thermal degradation, microdieseling, ESD, additive depletion, and contamination.

Figure 1: Top part of the Logic tree for ESD
Figure 1: Top part of the Logic tree for ESD

As shown in Figure 1, at the top of the logic tree, we start by placing our hypotheses on the tree, and then using evidence/facts, we can rule them out afterwards. This is a critical step as the investigation should be able to stand on its own in the court of law (even if it may not reach that point). The next hypothesis is the buildup of static in the oil. There are three possible ways for this to occur;

  • Clearances too tight (as discussed earlier, this can lead to molecular friction, which can induce static)
  • Less than adequate grounding system (if a proper grounding system doesn’t exist, then there isn’t an option for the static to dissipate)
  • Less than adequate conductivity of the oil (if the conductivity of the oil is too low, then the charge can build up and cause it to be dissipated along the system, such as the filters)

Now, we need to investigate each of the three main hypotheses stated and find out the root causes for them.

Let’s begin with the Clearances being too tight hypothesis.

For this hypothesis, we will ask the question, “How can clearances be too tight?”. In this case (and we will have to keep it general and in broad buckets, so we can drill down into these later and eliminate as necessary), there are three possible reasons:

  • The OEM could have designed the system such that it was less than adequate (LTA)
  • The flow rate could have been increased above the recommended threshold
  • Incorrect viscosity of the lubricant could cause additional friction (we will dive into this one later).

We will develop the other two hypotheses in Figure 2.

Figure 2: Investigating the hypothesis, "Clearances too tight"
Figure 2: Investigating the hypothesis, "Clearances too tight"

If we further investigate where the OEM did not design the system effectively, we can determine that the operating conditions were probably not adequately considered before implementation. This is a systemic root cause and one that needs to be addressed with the OEM.

On the other hand, if we investigated the flow rate, there could be two main reasons for the adjustment. One could be because of system changes, which forced adjustments to the flow rate. Since a decision was made here, it is a human root cause. Someone decided to change the flow rate based on the variables involved. However, if we investigate why these changes were made (once a human is involved, the question moves from how to why), we can determine that the system was not designed to accommodate these changes. This is a systemic root.

Similarly, if the operational conditions change (such as when a higher output is required, which is different from system changes), then the flow rate must be adjusted. Again, a decision must be made here, and a human is involved. Then we ask the question, “Why?”. In this case, we have the same systemic root, and the design is inadequate to accommodate the necessary changes.

For this part of the tree, we have found some human root causes where decisions were made, as well as systemic root causes. Both need to be addressed when we perform the final root cause analysis. For the human root causes, we can think about the procedures that guided them to make those decisions (if they existed) and amend these accordingly.

On to the next hypothesis, which we have yet to investigate (still under the clearances being too tight), the incorrect viscosity of the lubricant, which is shown in Figure 3. There are a couple of ways in which this can happen:

  • OEM recommendations were not followed
  • There was an unavailability of the specified viscosity of the lubricant
  • There was a less-than-adequate procedure for selecting the correct viscosity of lubricant

If we investigate why the OEM recommendations were not followed, we can find two main reasons. Either they were not documented and therefore could not be followed, or the internal best practice was used instead to replace the OEM recommendations. In both cases, these would be systemic root causes, and we should investigate why these were not documented or why they were replaced.

Figure 3: Investigating the hypothesis, “Incorrect viscosity of lubricant”
Figure 3: Investigating the hypothesis, “Incorrect viscosity of lubricant”

When investigating the unavailability of the specified viscosity of the lubricant, we can find two main causes. Either there was an issue with the restocking of this lubricant at the warehouse due to their forecasting, or appropriate checks were not carried out. This is a systemic root cause that should be investigated further.

Another hypothesis could be that the specified lubricant was unavailable from the supplier. This is another systemic root cause and should be addressed with the supplier to ensure it is resolved in the future.

When lubricant viscosity errors trace back to missing stock or missing training, the problem isn’t the person or the product – it’s the system that allowed both to fail.

On the other hand, if we examine the procedure for selecting the correct viscosity of the lubricant, we identify a human root cause, as someone would have made the decision on which viscosity to use. But in this case, we need to investigate why the person was not trained to determine this value.

There are two main reasons why a person does not receive training: either it doesn’t exist, or it was not followed. In both cases, these are systemic roots that need to be further investigated and addressed.

Now, we will investigate the next major hypothesis, “LTA grounding of the system” in Figure 4.

Figure 4: Investigating the hypothesis, “LTA Grounding of the system”
Figure 4: Investigating the hypothesis, “LTA Grounding of the system”

When investigating the grounding of a system, we can identify two major classes: either it doesn’t exist, or it didn’t meet the requirements. If grounding did not exist, then this is an inadequate system design and therefore a systemic root cause. On the other hand, if the grounding did not meet the OEM requirements, we need to determine how this was possible.

Figure 5: Investigation of the hypothesis, “LTA Conductivity of oil”
Figure 5: Investigation of the hypothesis, “LTA Conductivity of oil”

There are two possibilities: the site’s best practices were used to replace the OEM standards, which is something we often see, especially if these requirements have worked in the past. This is a systemic root cause that should be investigated. Or there were fewer than adequate components to achieve grounding.

In this case, we can have components that are not designed for the system (do not meet the system’s requirements) or components that were not OEM-recommended and are being used (such as aftermarket products that do not meet the necessary specifications).

Finally, on to the last major hypothesis, “LTA conductivity of the oil,” as shown in Figure 5.

As noted earlier, if an oil has a conductivity of more than 100pS/m, it will be able to dissipate any accumulated charge easily. However, if it falls below this value, the charge will be dissipated in the system at the earliest opportunity.

How can oil have less than adequate conductivity? Perhaps the elements of the oil have a less-than-adequate conductivity. If that is the case, then there can be two plausible reasons for this. Either the formulation was not appropriately designed, or the materials (base oils, additives) were not of a particular standard. Both causes are systemic root causes and should be investigated further to determine if anything can be done to correct these.

If we were to summarize a list of the root causes, we would see that many are systemic, while a few are human, as shown in Figure 6.

Figure 6: Summary of the root causes of ESD
Figure 6: Summary of the root causes of ESD

This further reiterates the need to develop a comprehensive logic tree when investigating any failure, as many root causes are not physical or surface-level. If these are not adequately addressed, the failure mode will recur in the future. The entire logic tree can be found here under additional support material, along with logic trees for other degradation mechanisms.

References

Mathura, S. (2020). Lubrication Degradation Mechanisms: A Complete Guide. Boca Raton: CRC Press.

Mathura, S., & Latino, R. (2021). Lubrication Degradation: Getting into the Root Causes. Boca Raton: CRC Press.

Find out more in the full article, "Root Causes of Electrostatic Spark Discharge in Modern Lubrication Systems" featured in Precision Lubrication Magazine by Sanya Mathura, CEO & Founder of Strategic Reliability Solutions Ltd. 

by
November 15, 2025
Oil Properties / Used Oil Analysis

What are Effective Strategies to Prevent ESD in Lubrication?

ESD occurs when there is a buildup of static in the oil; therefore, one of the best methods of preventing it is to ensure that the static levels remain low or are dissipated before they have a chance to wreak havoc on the system. The simplest and most common way of reducing this static is the installation of antistatic filters. These filters can help to remove static from the system before it builds up to dangerous levels, where it can burn the membranes or develop varnish.

Static in oil is inevitable – how you control and discharge it determines whether your system runs clean or burns itself from within.

Ensuring that the system is grounded correctly is another way to guarantee that any built-up static is removed. This is where your electricians can perform checks and install proper grounding devices for your equipment to safeguard against this buildup of static in the system. Therefore, if static charges get built up in the system, they can be dissipated without the effects of ESD.

If oils experience high levels of conductivity, they can conduct static. Typically, if the conductivity is above 100pS/m, there is potential for the fluid to conduct the charge and allow it to be discharged along the system without causing harm.

Unfortunately, there are base oils with low conductivity (below 100pS/m) that cannot carry the charge and dissipate more easily. As such, these types of oils will see an increase in the presence of ESD if not formulated correctly for modern lubrication systems.

As the viscosity of the oil decreases, more force is required to pass through the filters, which can lead to a buildup of static at a molecular level. Additionally, as temperatures decrease, the viscosity also decreases. In these cases, keeping the oil at the system temperature (designed for that particular viscosity) can help to reduce the buildup of static charge in the oil.

Find out more in the full article, "Root Causes of Electrostatic Spark Discharge in Modern Lubrication Systems" featured in Precision Lubrication Magazine by Sanya Mathura, CEO & Founder of Strategic Reliability Solutions Ltd. 

by
November 15, 2025
Oil Properties / Used Oil Analysis

Understanding Electrostatic Spark Discharge and Its Impact on Lubrication Systems

Electrostatic Spark Discharge typically occurs when static is built up in an oil at a molecular level, causing it to discharge in the system and create free radicals, which increase the opportunity for varnish to form. This usually occurs at temperatures of around 10,000 °C.

If we were to liken this to an everyday situation, we could think about walking around a carpeted room where the static builds up in our body. When we touch a metallic object (more than likely a door handle), we get a bit of a shock as the built-up static is discharged through us and the door handle.

Inside a lubricant system, static doesn’t just build – it ignites microscopic sparks powerful enough to scar filters and start the chain reaction that leads to varnish.

Similarly, in lubricants, static exists at a molecular level, and in areas of tighter clearances, some molecules are forced to rub against each other, causing a buildup of static. When it accumulates to the point of becoming a full charge, it dissipates at the first opportunity, usually at the filter membrane or some sharp-edged object along the way. These are seen as burnt patches on the filter membrane.

When this spark occurs, it creates a chemical reaction that generates free radicals. Free radicals are highly reactive species that need to engage with other substances. These are the initiators of varnish, and their presence can accelerate reactions, leading to deposits forming in the lubricant. Eventually, this will lead to a system that has experienced both ESD and oxidation.

In this article, we will discuss various identification methods and ways to prevent ESD in modern lubrication systems. We will also spend some time identifying typical root causes for ESD by developing a logic tree as a guide for future investigations.

 

How to Identify Electrostatic Spark Discharge in Lubrication Systems

Every degradation mechanism produces varying results in the form of deposits or in how these are formed. For ESD, some tell-tale signs alert the user to its occurrence. These include:

  • Crackling sounds / buzzing outside of components – This noise is representative of sparks as they discharge on part of the media/asset. Typically, this occurs when the fluid is in motion, allowing it to be heard near the filters when the system is operating.
  • Burnt or pinhole filter membrane – The filters usually feel the full effect of ESD, and small burn patches or even pinholes are created when ESD occurs. When changing filters, the membranes should be examined for these patches to determine if ESD is occurring.

Free radicals are produced when ESD occurs. As such, this leads to polymerization of the lubricant, which produces varnish and sludge. This is part of the oxidation process, and the antioxidant levels will begin to decrease. During ESD, certain gases are also released in the oil. Some of the lab tests which can be used for identifying where ESD has occurred include:

  • RULER® – Remaining Useful Life Evaluation Routine test, which quantifies the presence of antioxidants in the oil. By trending this over time, one will be able to determine whether the levels of antioxidants are decreasing or not. Typically, this test can be performed twice annually on larger sumps (such as turbines) or the frequency can be increased according to the criticality of the equipment. If the value gets below 25% then this is the critical limit, and methods to regenerate the oil or change it should be explored.
  • MPC – Membrane Patch Colorimetry – this measures the potential of the oil to form varnish or deposits. Depending on the equipment, the warning limits will vary, but a good rule of thumb is to treat results below 10 as normal, those above 15 as within the monitor range, and those above 20-25 as the critical range. Be sure to double-check these levels with the OEM of the equipment.
  • FTIR – Fourier Transform Infrared Spectroscopy can identify various molecules in the oil. It is likened to identifying the fingerprint of the oil, where each molecule has a specific characteristic spectra representative of that molecule. This test can be used to identify the presence of oxidation or any deposits that may have formed.
  • DGA – Dissolved Gas Analysis – this test can be used to identify the presence of particular gases that are released during ESD, such as acetylene, ethylene, and methane.

Those above are just some of the methods that can be used to identify the presence of ESD in a lubrication system.

Find out more in the full article, "Root Causes of Electrostatic Spark Discharge in Modern Lubrication Systems" featured in Precision Lubrication Magazine by Sanya Mathura, CEO & Founder of Strategic Reliability Solutions Ltd. 

by
November 15, 2025
Oil Properties / Used Oil Analysis

Interpreting the Oil Analysis Report in Practice

Now, we will actually read a report to help put all of these into practice.

Here is a sample report from Eurofins for a turbine oil. In this report, the various types of tests are classified according to wear metals, additives, and contaminants, as shown in Figure 2.

According to the report, samples have been collected over a period of time. This helps with the trending of the data, so we can spot when the values start varying from the “normal levels”. The reference values are also provided in the first column to help users determine whether these values fall within tolerance limits or not.

Figure 2: Sample Turbine Oil Analysis Report

Typically, the lab will provide some type of traffic light system where:

  • Red – indicates there may be an abnormal reading or the oil should be changed immediately, as certain values have surpassed the critical limits.
  • Amber – shows that the values are approaching the warning limits, but there is still some time to investigate and fix the problem.
  • Green – tells us that all values are within the tolerance limits and the oil is performing normally.

For this report, they also include additional tests as shown in Figure 3.

Figure 3: Additional Tests for Turbine Oils
Figure 3: Additional Tests for Turbine Oils

For turbine oils, understanding the demulsibility of the oil is important, as this is the oil’s ability to separate from water, or rather, not to form an emulsion. Excessive water in the oil can lead to rust or even a washout of the additives.

The Foam test is also administered to detect the oil’s ability to release air from the oil, ensuring that the air doesn’t get trapped. If air is trapped, it can lead to microdieseling and cavitation on the inside of the equipment.

RPVOT – Rotating Pressure Vessel Oxidation test is also performed, as it indicates the expected oxidation of the oil. MPC (Membrane Patch Colorimetry) and Ultracentrifuge detect the potential of the oil to form varnish, and the RULER® values give the actual quantity of antioxidants present.  These values are all critical for monitoring the health of the turbine oil, as it is very susceptible to oxidation and the formation of varnish.

In essence, reading the oil analysis report involves understanding what the tests are meant to measure, knowing your equipment and its operating conditions, and having a history of your equipment.  These factors all contribute to trending the data to ensure that there are no surprises with unplanned downtime due to wear or oil degradation.

References

Eurofins. (2025, September 06). Annual Turbine Analysis. Retrieved from Eurofins Testoil: https://testoil.com/services/turbine-oil-analysis/annual-turbine-analysis/

Find out more in the full article, "How to Read Oil Analysis Reports and translate Data into Reliability" featured in Reliable Magazine by Sanya Mathura, CEO & Founder of Strategic Reliability Solutions Ltd. 

by
November 15, 2025
Oil Properties / Used Oil Analysis

How to Interpret Your Oil Analysis Results

Have you ever received your bloodwork results from your doctor, only to be more confused than ever? With all the long names and numbers just sitting on the piece of paper, Google (or ChatGPT) becomes your best friend to help interpret what they mean. However, even with these tools of reason, there is usually a disclaimer that states, “Please consult your doctor for a more accurate interpretation”.

Numbers alone don’t tell the whole story – context is what makes oil analysis meaningful.

One of the reasons for constantly looping your doctor back into the mix is that they have your history, they know how your body responds to certain things, and values which may get flagged because they are outside of the limits may be waived away by your doctor because it is normal for your body based on your history and DNA.

The same applies to oil analysis. Depending on the application and operating environment, certain conditions may be met that can be interpreted as unusual. Still, if you’re familiar with your system, you will understand the reason behind the numbers.

Figure 1: DIN 515519 table showing viscosity limits
Figure 1: DIN 515519 table showing viscosity limits

Viscosity

As mentioned earlier, viscosity is the most important characteristic of a lubricant. If it is too thick for the application, this can lead to efficiency loss, increased heating, and a slowdown of the system. Essentially, a significant amount of work needs to be done on the oil to make it compatible with the application.

On the other hand, if it is too thin, then we run the risk of improper lubrication. Therefore, we increase the chances of wear occurring in the applications.

Viscosity is usually measured at either 40°C (for industrial applications) or 100°C (for engine applications). However, most labs put a ±5% tolerance limit for many oils. But why use such a random figure? The DIN 51519 table is used to determine ISO viscosity, with each value within a 10% range, as shown in Figure 1.

When you see an ISO VG 100 oil, the chances are that the actual viscosity of that oil varies between 90-110cSt. Therefore, if we start seeing our results vary by around 5% or trend towards the outer limits of any viscosity class, we know that something is going on with our oil.

Presence of Wear Metals

Wear metals prove that some type of wear is occurring. However, depending on their quantity, they can also provide some more insights into what is actually wearing away and whether it is normal wear or abnormal wear. Wear is reported in parts per million (ppm) or as a percentage. Here’s how to convert those percentages to ppm:

100% = 1,000,000ppm

1% = 10,000ppm

0.1% = 1,000ppm

The most common wear metals tested include Aluminum, Iron, Chromium, Copper, Lead, and Tin. Depending on the application, there are varying levels at which these will be flagged.

Table 1 provides an example of various applications and their respective limitations. These will vary based on your OEM and environment, but can be used as a general guideline. All numbers in Table 1 are in ppm.

Table 1: Wear metal limits for various applications
Table 1: Wear metal limits for various applications

AN/BN and the Presence of Contaminants

Contaminants are any foreign material in the system. Sometimes, lab tests may not be able to detect contaminants in a system because they are not specifically designed to identify that particular contaminant.

In these cases, users would need to specify what additional contaminants the lab should look for, or perform a broader FTIR (Fourier Transform Infrared) analysis to identify all the components in the oil and then determine which of them are contaminants.

The most common contaminants tested include Silicon, Water, and Fuel. Although AN/BN (Acid Number and Base Number) may not be considered a contaminant, it helps quantify the acid in your system, which shouldn’t be there; therefore, in some ways, it can be viewed as a contaminant. However, it is primarily a physical property and is listed separately.

Acid and base numbers act like an early warning system for oil health.

Table 2: Tolerance limits for some contaminants
Table 2: Tolerance limits for some contaminants

For diesel engines, BN is measured as having high base numbers, which will decline over time as acids accumulate. If the BN value declines to around 50% of its original value, then we have an issue with the acids increasing too quickly in the oils. On the other hand, AN is used for all other industrial oils (gears, hydraulics, etc.). There are varying limits for AN depending on the application, as shown in Table 2.

Silicon usually indicates the presence of sand, which is highly abrasive. This can accelerate wear in any equipment by essentially turning the oil into sandpaper and wearing away the insides of the equipment. Some of its limits are shown in Table 2.

Water in any form is highly destructive to all assets. However, some systems can tolerate a bit more water than others. This can be due to the nature of the oils (good demulsibility) or the nature of the systems, where heat is involved to help remove the water. Water in the system can lead to an increase in viscosity and disrupt the oil layer.

As such, the lubricant will not be able to form a full film to protect the asset. Water can also create an emulsion in the oil or lead to corrosivity issues. Table 2 gives some examples of limits for various systems.

Fuel contamination is an issue for most diesel engines. The presence of fuel in your oil can lead to a lower viscosity (hence the oil can no longer protect the components) and an increase in the flash/fire point of the oil, which can be particularly dangerous. We have some limits noted in Table 2.

 

Presence of Additives

It is more challenging to place these tests in a one-size-fits-all table, as oil formulations are consistently changing. The best way to interpret these additives would be to compare them against the initial values for the finished lubricant.

For your oil analysis program, always have a representative sample of the new oil so that comparisons can be made against it as the oil ages in the system. Additionally, the presence of additives in your report when they shouldn’t be there is also a sign of contamination, likely with another type of oil.

Find out more in the full article, "How to Read Oil Analysis Reports and translate Data into Reliability" featured in Reliable Magazine by Sanya Mathura, CEO & Founder of Strategic Reliability Solutions Ltd. 

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November 15, 2025
Oil Properties / Used Oil Analysis

Why Different Oils Require Different Tests

Oil analysis reports often wear an invisible cloak, and only if we have a wizard capable of revealing what the numbers mean, they will more than likely end up in a drawer or file on the computer. There are many similarities between oil analysis and blood tests, as they both serve similar functions.

They both test fluids, quantify the results according to different categories, and provide envelope limits within which these values should exist. If the values fall outside these limits (either below or above), we need to take action to prevent failure of the critical asset (or human organ accordingly).

An oil analysis report is less about numbers and more about the story they reveal.

In this article, we will focus on understanding the basics of reading an oil analysis report, interpreting the results, and developing action items based on the information collected. We will take a closer look at reports on turbines (rotating equipment), gear, hydraulics, and engine oils, and what this all really means for your equipment.

Why Different Oils Require Different Tests

Before we dive into the report, we need to establish that not all oils are the same! As such, different oils are required for various types of applications. Therefore, each type of oil will require slightly different tests to determine whether it is performing optimally or not. However, there are a few tests that remain the same for all oils.

The most critical characteristic of an oil is its viscosity. As such, all oils are typically tested to determine whether their viscosity meets the requirements. Another function of the oil is to prevent wear. Thus, most oils are tested for the presence of wear particles, as this can help the user identify if any wear is occurring in the asset.

Oils should be kept clean; therefore, tests are performed to determine the presence of any contaminants, and these are carried out on most oils. Similarly, additives help oils perform their functions; hence, their presence or absence should be quantified to determine if they are indeed achieving their functions for all oils.

Tests for viscosity, the presence of wear metals, contaminants, and additives are the standard sets of tests that should be performed on any oil. There are more detailed tests that examine the specifics of various types of applications, but we will delve into these later in the article.

Find out more in the full article, "How to Read Oil Analysis Reports and translate Data into Reliability" featured in Reliable Magazine by Sanya Mathura, CEO & Founder of Strategic Reliability Solutions Ltd. 

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November 15, 2025
Oil Properties

How should you store and dispose of hydraulic oil safely?

Hydraulic oils are easily contaminated, particularly during storage and handling. Due to the tight clearances in hydraulic systems and their function of transmitting power, any contaminant can cause an issue with the system’s efficiency. As such, it is crucial to store and dispose of these oils properly.

Every ounce of contamination prevented during storage saves hours of troubleshooting later.

Proper storage of hydraulic oils includes keeping the containers closed and protected from the elements, as this prevents dirt particles from entering easily. These oils should not be stored in an area that is not covered or exposed to the elements, as this increases the risk of contamination. For any oil that is decanted into smaller containers, filters should be used during decanting (into a clean container) and upon decanting into the equipment to minimize the transfer of particles from the outside.

When hydraulic oil reaches the end of its life, it must be disposed of properly. In different countries, various rules and regulations govern this disposal. In many countries, a certificate of custody and chain of transfer is required when moving used hydraulic oils from the equipment site to the site where they are disposed of. Some waste oil removal companies ask that the hydraulic oils be separated from other oils, especially in cases where these will be re-refined to create new oils.

Find out more in the full article, "Hydraulic Oil Basics: Functions, Types, and Performance Factors" featured in Precision Lubrication Magazine by Sanya Mathura, CEO & Founder of Strategic Reliability Solutions Ltd.