Tagged: engineer

Hidden Failures in Lubrication programs: Designing a Resilient Lubrication Strategy Part 3

Before you begin to design a resilient lubrication strategy, you need to know where your current lubrication strategy falls as per industry standards. You can review part 1 in this series where we break down the various levels of maturity for lubrication programs. Afterwards, determine your hidden failure modes which you can read about in part 2 of our series.

As a quick refresher, here are the various maturity levels for lubrication programs.

Varying-levels-of-Maturity-for-Lubrication-Programs_870x460 (1)
Figure 1: Varying levels of Maturity for Lubrication Programs

Once the current lubrication program level is identified, we then need to audit the systems that we have in place to understand what gaps need to be filled. While wanting to achieve level 5 is always the goal, we also must be cognizant of our constraints. Within our industry, some constraints which typically exist include; budget, manpower, resources and time. Each of these have crucial roles to play in determining the success of our lubrication program.

Closing the gaps

Once your gaps have been identified, this is not the end of the story. We need to put procedures and strategies in place to make sure that we can close these gaps. This is where we get to re-evaluate work orders, ensure that they are now being aligned with our condition monitoring programs and design our systems to have proper lube routes as well as frequencies or relubrication with the correct lubricant.

After auditing our condition monitoring program (which forms part of the lubrication program), we should also assign dedicated personnel for interpretation of oil analysis results as well as sampling. Being able to access consistent data and trending will help us to understand our equipment better and possibly detect failures before they occur.

Part of auditing of condition monitoring program includes setting up alarm limits within our system which are aligned to our equipment and environment. While the lab will have the standard set of alarms, we should take a closer look at what really resonates with our equipment. For instance, if we start seeing a spike in copper right after a turnaround where certain parts were changed, then this may be normal and just break in wear. However, the lab may flag it as a component failing (if we did not provide them with adequate details).

Contamination

One of the biggest sources of failures for our equipment is contamination. By designing our lubrication program to eliminate sources of contamination (within or control), we can essentially minimize equipment failure. Most contamination can happen during oil transfer to equipment where the oil may either be placed in dirty containers, or have contaminants enter their packaging from improper storage conditions.

By designing our lubrication program to address contamination and have measured results as goals for our program, we can improve our systems. Without clear cleanliness targets we cannot evaluate the impact of reducing contamination. Desiccant breathers and proper sealing techniques can also help in reducing the ingress of contaminants into the system.

Training and Accountability

Designing a lubrication program must also include the training of the employees to execute the program. They are the ones responsible for its success and if not trained or briefed about the importance of their assigned roles, then they will not bring the value to the program and unfortunately, it will fail.

By allocating responsibilities to employees and having them accountable for these roles it brings some form of ownership into the program. This allows the program to thrive more as they are genuinely invested in making it a success. Once they have been trained, they can in turn continue to spread the word about lubrication and best practices to their peers.

oil-analysis-test-to-identify-health-of-lubricant_870x460
Figure 2: Oil Analysis Tests which can be performed to identify health of lubricant

Essentially, we can have hidden failures in our lubrication programs, but we can uncover these and redesign our program to become a success through auditing and putting proper strategies in place. Next time you think about your lubrication program, explore its robustness and think about ways in which you can improve it to ensure that it is adding to the value that it should.

Hidden Failures in Lubrication programs:  Failure Modes Which Are Not Being Monitored Part 2

In part 1 of this series, we took a closer look at the Illusion of a Good Lubrication Program. One of the key findings was that through audits, failure modes were not being monitored actively or in some cases not at all. In this part of the series, we will do a deeper dive into the failure modes that can be missed with lubrication programs.

Critical but not obvious failure modes

With our standard oil analysis programs, there are a few key tests that can indicate the health of an asset. These include; viscosity, presence of wear metals, contaminants, additives, moisture levels and cleanliness levels (ISO 4406). From these tests, we can easily identify if we may have some cause for investigation or concern.

oil-analysis-test-to-identify-health-of-lubricant_870x460
Figure 1: Oil Analysis Tests which can be performed to identify health of lubricant

If there are changes in viscosity this can be an indication of a few different things. A decrease in viscosity can indicate that there is possible contamination with fuel or even thermal cracking of the lubricant. However, if the viscosity increases, this can indicate contamination with water (or another higher viscosity grade lubricant, accidentally) or the presence of oxidation degrading the lubricant.

The presence of wear metals can indicate that there is wear occurring within your components. However, there are varying limits depending on the type of oil and the application in which it is being used. For instance, the alarm limit for iron in diesel engines is usually around 60ppm while the alarm limit for iron in gearboxes is closer to 300ppm (this will vary by OEM). As such, it is important to set appropriate alarm limits for various components and oils depending on their applications and environments.

If there is the presence of contaminants, this can easily flag that something is getting into the system (either via an external or internal source) which shouldn’t be there. Contaminants can also act as catalysts to speed up degradation of lubricants. Again, they have varying limits depending on application and type of oil, but they should be monitored.

By understanding the concentration of additives and observing their trends, we can also determine if wear is occurring (by the decline in antiwear additives) or if oxidation is happening (by the decline in antioxidants). By quantifying the concentration of additives, we can also determine if there was possible contamination with another lubricant (if an element shows up which should not be there!). Through the monitoring of additives, we can quickly determine the internal conditions that the lubricant is exposed to, whether or not wear is occurring and if contamination is present.

Assessing the Gap

These tests can give an indication of what’s happening inside your oil before the failures occur. Through proper trending and by establishing alarm limits which can warn users in time, failures can be avoided. This is the value of developing a robust lubrication program where impending failures can be detected, avoided and uncovered before they cause any harm to our system.

Stay tuned for part 3 where we dive into designing a resilient lubrication strategy.

Hidden Failures in Lubrication programs: The Illusion of a Good Lubrication Program Part 1

Typically, when lubrication programs are developed and implemented, everyone automatically believes that all lubrication issues have been solved and will never occur again. This is furthest from the truth! In this 3-part series, we will explore some of the hidden failures in lubrication programs. We will start off with dispelling the illusion of a good program then dive deeper into the failure modes which are not being monitored and finally, ways to design a resilient lubrication strategy.

How “good’ is good?

Many manufacturing plants have some form of a lubrication program in place. But many are not familiar with how to gauge this against best practices or industry standards. The following figure gives a brief description of the various stages of a lubrication program that can exist.

Varying-levels-of-Maturity-for-Lubrication-Programs_870x460 (1)
Figure 1: Varying levels of Maturity for Lubrication Programs

Although many plants may fall within the L2-L4 stages (and some in the L1 stage), there is still a lot of data missing on the documentation on lubrication failures and how these are being addressed (if they are being addressed at all). As such, there are no direct actionable items that link failures to strategies for preventing these in the future.

Industry standards attribute that around 33% of bearing failures are due to lubrication challenges. However, if our lubrication program is not capturing these lubrication related failures then the real root causes are not being addressed directly for these issues. As such, they are not being solved and we are adding to the overall unreliability of the plant. In these instances, our lubrication program is not adding value from a reliability perspective and is actually hiding some failures.

The real failures

Lubrication can account for a significant number of failures, but contamination also plays a crucial role. As per a study carried out by NRCC & STLE (National Research Council Canada & Society of Tribologists and Lubrication Engineers), particle induced failures are responsible for approximately 82% of failures. This means that our equipment is majorly failing because of contamination.

In our “Defined” maturity level 3 program, contamination is not even addressed. Hence, we could be missing the opportunity to remove this from our system and by extension reduce failures associated with contamination. With our level 3 program, we also do not have alarm limits for our oil tests to help us understand if we are approaching dangerous levels or not. This will cause us to miss opportunities where we could have prevented components from failure.

Even with a moderately tiered lubrication program, we are missing a lot of opportunities for improvement of the overall reliability of our plant. This can lead to the lubrication program being viewed as unsuccessful when in fact, it just didn’t capture the right data.

Apart from capturing data, we also need to act on that data. Even if we have an oil analysis program in place, if we are not trending the data or coordinating with our maintenance teams to troubleshoot potential issues, then the lubrication program is not helping to raise the reliability of the plant. The program is in fact hiding some of these inefficiencies.

When was your last audit?

Even though we may have built a lubrication program, have we audited it? Creating a lubrication program may be an easy feat for many but implementing it is another story in itself. This is where some programs fail because they exist on paper but not in practice. If our technicians are not collecting the right data or observing proper storage and handling techniques, then the lubrication program is just another piece of paper in the drawer collecting dust.

For those who have managed to get the lubrication program off the ground and have the right people integrated into it, an audit on the program is still a good idea. Sometimes when these programs are launched, the personnel responsible are excited to implement the new strategies but complacency can easily step in. This is when the quality of the results of the program can erode.

Your program may no longer be catching your failures in advance, and this can lead to a loss in production, emergency repairs and even unplanned shutdowns. Performing annual audits on your lubrication program to ensure that it is delivering actionable results is highly recommended.

Many failures and incompetencies can hide behind a “good lubrication program” but with proper auditing and identification of where your lubrication program actually measures up, you can take actions to make it a successful program.

Stay tuned for part 2 where we will be diving deeper into the failure modes that are not being monitored.

The Ideal Lube Room

While many may think it is costly or impossible to transform their current lube room, there are a few low-cost adjustments which can be made to help reduce the initiation of failure in this area.

As shown in Figure 2, these small changes can have big impacts on reducing the contaminants which get into the oils before they are added to the machines.

ideal-lube-room
Figure 2: Strategies for an Ideal Lube Room.

By implementing some of the aforementioned strategies, we can see an immediate reduction in the number of failures which occur at a facility. While many think about investing in predictive technologies which may range to the higher cost bracket, these simple adjustments to the lube room can easily solve a large percentage of the issues.

If we were to think about this in terms of the cost of the failures for gearboxes or other critical pieces of equipment, the investment in these strategies to upgrade your lube room is minimal. When investigating your next failure, perform a full root cause analysis and determine whether it’s stemming from your lube room. Chances are that you have the opportunity to prevent a lot more failures than you would expect.

Find out more in the full article, "Why Asset Failures Often Start in the Lube Room" featured in Precision Lubrication Magazine by Sanya Mathura, CEO & Founder of Strategic Reliability Solutions Ltd

Mislabeling and Environmental Conditions in the Lube Room

Thus far, we’ve spoken about the effects of mainly physical contamination but quite a number of things also happen in the lube room. One major aspect of compromise is proper labelling of the lubricants. Many times, technicians are in a rush to get their lube route underway and will often not double check that they have the correct lubricant for the application that they are working on. In these cases, they may have picked up the wrong lubricant which is not the appropriate viscosity or suited for the application either!

This can lead to incompatible lubricants being mixed causing a series of failures. It can also lead to incorrect viscosity being applied to the equipment causing wear and tear or efficiency losses. Additionally, if the wrong type of oil is used, this can also lead to severe bleaching of the additives out of the oil.

For instance, if a motor oil (which contains 30% additives) was placed in a hydraulic oil sump, this can lead to catastrophic events where the additives in the motor oil may trap water getting into the hydraulic oil making it emulsify rather than allowing the water to drop out.

As such, we need to ensure that there are adequate labeling systems in place to minimize the occurrence of a mix up with the lubricants. Colour coding can also help as this reduces the errors of “picking up” the wrong dispensing container especially when our technicians are in a hurry.

The environment has a huge role to play regarding the integrity of lubricants. If lubricants are stored outside in drums, they have the tendency to collect rainwater. They can breathe and draw in this rainwater which gets collected at the top of the drum. This breathing action occurs due to changes in temperature such as the change from a bright sunny environment to a rainstorm. This introduces water into the oil and contaminates it before it reaches the equipment. Lubricants should be stored at controlled temperatures between 0–25°C and in a sheltered area.

Find out more in the full article, "Why Asset Failures Often Start in the Lube Room" featured in Precision Lubrication Magazine by Sanya Mathura, CEO & Founder of Strategic Reliability Solutions Ltd

Addressing Contamination in the Lube Room

When we think about the lube room, there can be a few images which come to mind. Either a pristine environment, with everything colour coded, neatly packed on the assigned shelves, dedicated storage and handling containers and a temperature-controlled environment (everyone’s dream!).

Or we can have a mix of dirty, oily rags, creatively designed dispensing containers where the welders were definitely showing off their skills and mislabeled (or no labels) on the lubricants. We can also have many images in between since there is a range of things which can be done (or not done) by those in charge of the lube rooms given their environmental conditions and constraints (budgetary or operational).

Unfortunately, the lube room is the place where many failures can begin if the conditions are not appropriate. It should ideally be the first line of defense for our assets but is often overlooked. Typically, this is the starting point of the journey for any lubricant and if it carries contaminants then we are exponentially decreasing the life of our lubricated assets before they have a chance to operate in our facility. This article explores the ways in which we can reduce these effects and some areas of improvement for any lube room.

 

Addressing Contamination

The ISO 4406 test is one that the industry is very familiar with as it governs the cleanliness of the oil. Typically, every system / OEM has a targeted cleanliness level. But how does the cleanliness level actually impact the lubricant and its functions? It is often said that the industry runs on a film of oil that is between 1–10 microns. Essentially, that means that any particle which is larger than this range interrupts the film and can cause damage and wear to the components.

For those not familiar with ISO 4406, this quantifies the number of particles into three categories, ≥4μm / ≥6μm / ≥14μm particles per milliliter of fluid. Each category measures the quantity of particles that fit the size bracket and then these are translated to a scaled number. As such, the numbers represented are not the actual quantity of the particles of that size.

ISO-4406
Table 1: ISO 4406 rating scale.

Therefore, an ISO code of 20/15/13 represents:

20 between 5,000 – 10,000 particles larger than 4μm in one milliliter of fluid
15 between 160 – 320 particles larger than 6μm in one milliliter of fluid
13 between 40 – 80 particles larger than 14μm in one milliliter of fluid

New oil delivery in container sizes between a pail or a truck load, the cleanliness value can be excellent. Sometimes these values can be as clean as ISO 16/14/11, but can also be quite poor. A 16/14/11 score is great, but perhaps our turbines or hydraulic systems particularly those with EHC systems require something more stringent (due to their tighter clearances) such as ISO 14/12/9. The table below shows a comparison of what that actually means as it relates to the number of particles in the oil for these ratings.

table2
Table 2: Comparing new oil to Turbine oil specifications for EHC systems.

As we see in Table 2, there is a major difference between the number of particles at the 4 micron level between what is being delivered to the facility as new oil versus what the turbine actually requires. When we translate that to the fact that bearings in turbines may run on a film of oil which is between 1–10 microns, and our new oil has potentially 640 particles that are bigger than 4 microns, then we can conceptualize that the oil film will most definitely be disrupted!

This ISO cleanliness level starts off from the entry of the “clean” lubricant into the plant. If we factor in drums which have been exposed to the atmosphere, dirty transfer containers which already contain contaminants or bad practices (leaving hoses open to the atmosphere), then the ISO contaminant ratings will significantly increase. This means we are literally pouring contaminants into our oils and our assets.

Thus far, we have only described the contaminants in the form of solid particles, but contaminants can also exist in the liquid form (fuel, water, other lubricants, process liquids) or gaseous form (air, process gases). These can all affect the lubricant either acting as catalysts or fouling the system.

 

The Unseen Failure Chain

When we think about starting from the lube room and tracing the chain of events which leads to failure, it will look similar to Figure 1 below.

failure-chain
Figure 1: Chain of failure events.

In this case, contaminants start off in the lube room, and they enter the equipment, wreak havoc and then lead to failure. During many failure investigations, the analyst stops at the physical root causes and can easily blame the component. Since they did not investigate further, they missed that the source of contamination actually came from the lube room and possibly bad storage and handling practices.

Find out more in the full article, "Why Asset Failures Often Start in the Lube Room" featured in Precision Lubrication Magazine by Sanya Mathura, CEO & Founder of Strategic Reliability Solutions Ltd

Hidden Failures in Lubrication programs: The Illusion of a Good Lubrication Program – Part 1

Typically, when lubrication programs are developed and implemented, everyone automatically believes that all lubrication issues have been solved and will never occur again. This is furthest from the truth! In this 3-part series, we will explore some of the hidden failures in lubrication programs. We will start off with dispelling the illusion of a good program then dive deeper into the failure modes which are not being monitored and finally, ways to design a resilient lubrication strategy.

How “good’ is good?

Many manufacturing plants have some form of a lubrication program in place. But many are not familiar with how to gauge this against best practices or industry standards. The following figure gives a brief description of the various stages of a lubrication program that can exist.

Figure 1: Varying levels of Maturity for Lubrication Programs

Although many plants may fall within the L2-L4 stages (and some in the L1 stage), there is still a lot of data missing on the documentation on lubrication failures and how these are being addressed (if they are being addressed at all). As such, there are no direct actionable items that link failures to strategies for preventing these in the future.

Industry standards attribute that around 33% of bearing failures are due to lubrication challenges. However, if our lubrication program is not capturing these lubrication related failures then the real root causes are not being addressed directly for these issues. As such, they are not being solved and we are adding to the overall unreliability of the plant. In these instances, our lubrication program is not adding value from a reliability perspective and is actually hiding some failures.

The real failures

Lubrication can account for a significant number of failures, but contamination also plays a crucial role. As per a study carried out by NRCC & STLE (National Research Council Canada & Society of Tribologists and Lubrication Engineers), particle induced failures are responsible for approximately 82% of failures. This means that our equipment is majorly failing because of contamination.

In our “Defined” maturity level 3 program, contamination is not even addressed. Hence, we could be missing the opportunity to remove this from our system and by extension reduce failures associated with contamination. With our level 3 program, we also do not have alarm limits for our oil tests to help us understand if we are approaching dangerous levels or not. This will cause us to miss opportunities where we could have prevented components from failure.

Even with a moderately tiered lubrication program, we are missing a lot of opportunities for improvement of the overall reliability of our plant. This can lead to the lubrication program being viewed as unsuccessful when in fact, it just didn’t capture the right data.

Apart from capturing data, we also need to act on that data. Even if we have an oil analysis program in place, if we are not trending the data or coordinating with our maintenance teams to troubleshoot potential issues, then the lubrication program is not helping to raise the reliability of the plant. The program is in fact hiding some of these inefficiencies.

When was your last audit?

Even though we may have built a lubrication program, have we audited it? Creating a lubrication program may be an easy feat for many but implementing it is another story in itself. This is where some programs fail because they exist on paper but not in practice. If our technicians are not collecting the right data or observing proper storage and handling techniques, then the lubrication program is just another piece of paper in the drawer collecting dust.

For those who have managed to get the lubrication program off the ground and have the right people integrated into it, an audit on the program is still a good idea. Sometimes when these programs are launched, the personnel responsible are excited to implement the new strategies but complacency can easily step in. This is when the quality of the results of the program can erode.

Your program may no longer be catching your failures in advance, and this can lead to a loss in production, emergency repairs and even unplanned shutdowns. Performing annual audits on your lubrication program to ensure that it is delivering actionable results is highly recommended.

Many failures and incompetencies can hide behind a “good lubrication program” but with proper auditing and identification of where your lubrication program actually measures up, you can take actions to make it a successful program.

Stay tuned for part 2 where we will be diving deeper into the failure modes that are not being monitored.

What Tools Can Be Used to Monitor Additive Depletion?

There are some basic analytical tools that can be used to measure the quantity of additives in oils. The spectroscopy methods are the FTIR (Fourier Transform Infrared) and ICP (Inductively Coupled Plasma). Another method is the RULER® test exclusively designed for antioxidants.

With FTIR and ICP methods, users obtain quantitative values for the elements present in the tested oil sample. These are usually reported in ppm and trended over time. Figure 2 shows an extract from a Turbine Sample report from Eurofins lab, where the levels of additives (and contaminants) are shown. When trending this, analysts should pay attention to the rate at which these additives decrease and whether an increase or decrease is noticed.

Figure 2: Sample of Eurofins Turbine Oil Analysis Report showing the levels of additives
Figure 2: Sample of Eurofins Turbine Oil Analysis Report showing the levels of additives

Another tool that can be used is the RULER® (Remaining Useful Life Evaluation Routine) test, which specifically quantifies the levels of antioxidants remaining in the oil. It trends the values, compares them against the baseline for that oil, and then determines the change as a percentage.

If the RULER value falls below 25%, the antioxidant levels have reached a critical level, and one may consider replacing the oil.

Figure 3 shows a RULER graph, which identifies the presence of different types of antioxidants (Amines) and antiwear additives (ZDDP), as well as oxidation products (Fluitec, 2022).

This is a comprehensive readout of the quantities of these additive types at the time of sampling. It is easy to get a quick snapshot of its trend over time and determine whether it is declining rapidly or reaching critical levels.

Figure 3: RULER Graph showing the presence of antioxidants
Figure 3: RULER Graph showing the presence of antioxidants

The key to using these analytical tools is to provide insight into what is happening inside the equipment, allowing us to determine whether any preventive action is needed.

By monitoring the quantities of these additives over time, we can easily establish whether oxidation is occurring, which can lead to varnish and overheating of the asset. We can also determine whether significant wear is occurring as the antiwear additives are depleted (confirmed by the presence of wear metals in the oil analysis). When monitoring your asset’s health, trending specific additive levels can also be very useful.

References

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

Fluitec. (2022, September 29). Why is LSV Used for RULER Analysis? Retrieved from Fluitec: https://www.fluitec.com/2022/09/29/why-is-lsv-used-for-ruler-analysis/

Find out more in the full article, "Lubricant Additive Depletion as an Early Asset Health Signal" featured in Precision Lubrication Magazine by Sanya Mathura, CEO & Founder of Strategic Reliability Solutions Ltd. 

How Can Additives Deplete?

Additives can be depleted through different mechanisms. Some of these include:

  • Regular consumption through normal functioning of the lubricant
  • Antioxidant depletion during oxidation
  • Antiwear depletion due to high wear on the inside of the equipment
  • Additive depletion via a contaminant to produce a bleaching effect

As mentioned earlier, additives are sacrificial in nature. It is very normal to see additives deplete over time; if they are not depleting and increasing, this may be a cause for concern. This can mean that someone is topping up the oil frequently or perhaps topping up with an incorrect lubricant.

Since there are numerous oils on the market, the best way to monitor the depletion of your additives is to compare them against a new sample of that oil and use that as your baseline. Your lab will help you confirm when the additive limits are approaching the danger zones.

During oxidation, a free radical is formed under conditions such as heat, wear, metal catalysts, oxygen, or water. These free radicals are unstable, and antioxidants usually neutralize them.

In the process, antioxidant levels decrease. However, if the conditions still permit oxidation, more free radicals will be formed. This means that more antioxidants will be depleted as they neutralize the free radicals until they diminish and can no longer protect the base oil. This is when the free radicals begin to attack the base oil, and varnish can form.

Once the antioxidants are gone, the oil stops defending – and starts degrading.

If there are causes of high wear, such as the incorrect viscosity of the lubricant (too thin) or the machine finishing of the inner parts of a component not being done to the required standard, this can affect the levels of antiwear in the oil. Antiwear additives protect the metal surfaces inside the equipment. However, these are only activated when moderate stress exists within the equipment.

Typically, in these situations, the antiwear additive adheres to the metal surface and helps protect it by forming a layer. Once this layer is formed, the antiwear additive has officially left the oil, and this will be reflected in a decrease in its value in the oil analysis report.

The layer will not remain forever, and due to wear on the equipment, it can be worn off and replaced by a new layer, leading to further depletion of the antiwear additives until there are no more to form another layer or protect the metal surface.

Contamination can also cause some additives to become depleted. Contaminants can react with additives, causing them to form deposits that leave the oil. Therefore, their presence will not be detected by oil analysis.

Some common contaminants are water, fuel, coolant, and acids. These contaminants can also promote the formation of catalysts for degradation mechanisms such as oxidation. Dirt and solid particles can also promote additive depletion, especially when they act as catalysts.

Find out more in the full article, "Lubricant Additive Depletion as an Early Asset Health Signal" featured in Precision Lubrication Magazine by Sanya Mathura, CEO & Founder of Strategic Reliability Solutions Ltd. 

Why Do Additives Matter?

Oils are composed of base oils and additives. Typically, additives are sacrificial; they deplete first before the base oil is affected. As such, by trending their quantities over time, we can gain insight into a few of the conditions to which the oil is subjected.

By interpreting these conditions and patterns, we can correlate them with the health of the asset and plan accordingly for possible repairs or maintenance. In this article, we will do a deeper dive into ways these can be explored to add value to your asset management program.

Additives come in various ratios and chemical compositions, but when we talk about additives in oils, they really have three main functions. They can either;

  • Enhance the properties of the base oil, which already exist
  • Suppress the undesirable base oil properties or
  • Impart new properties to the base oil
Figure 1: Functions of additives and examples
Figure 1: Functions of additives and examples

On their own, they cannot affect anything, but when coupled with a base oil, they can impact an asset. Base oils also have specific properties, which, when combined with additives, allow assets to perform at their best.

The real performance comes from how the additives and base oil work together.

As shown in Figure 1, some additives that enhance properties include antioxidants, corrosion inhibitors, anti-foam agents, and demulsifying agents. Those responsible for suppressing undesirable properties can include pour-point depressants and viscosity improvers.

Finally, those responsible for imparting new properties include extreme-pressure additives, detergents, metal deactivators, and tackiness agents.

Here are some quick descriptions for a few of these additives, which will help you to gain an appreciation of their functions:

Antioxidants: these protect the oil from oxidation. They are very common in Turbine oils but can be found in many other oils. They are the first line of defense when oxidation begins and react with free radicals to neutralize them before they attack the base oil.

Corrosion inhibitors: adsorb onto the metal surfaces to help protect them. Comprised of sodium sulphonates, alkylbenzene sulphonates, or alkylphosphoric acid partial esters.

Anti-foam agents: reduce surface tension to break up foam formation. Typically, these are silicon-based, although silicone-free defoamers also exist.

Demulsifying agents: enable water and oil to separate. These were formerly composed of barium and calcium, but modern formulations use special polyethylene glycols.

Pour point depressant: alters oil crystallization, allowing the oil to form fewer crystals at lower temperatures.

Viscosity improvers: specifically designed to ensure that the viscosity of the lubricant can be more tolerant of changes in temperature and shear.

Extreme pressure additives: used under high stress to prevent the welding of moving parts. Usually comprised of a phosphorus compound.

Antiwear additives: designed to reduce wear under moderate stress. The most famous sulphur-phosphorus compound is ZDDP (Zinc Dialkyl dithiophosphate).

Detergents: keep oil soluble combustion products in suspension (especially for engine oils) and ensure they do not agglomerate. These usually contain metal additives such as Calcium and Magnesium.

Understanding the function and composition of these additives can help us to determine how they are performing in the oil. Since many of these are sacrificial, their values will decrease over time. As such, it is important to trend these values to determine whether they are remaining constant, increasing, decreasing, or decreasing at an accelerated rate.

Find out more in the full article, "Lubricant Additive Depletion as an Early Asset Health Signal" featured in Precision Lubrication Magazine by Sanya Mathura, CEO & Founder of Strategic Reliability Solutions Ltd.