Tagged: varnish

Varnish Badges of Honour

Varnish Badges_honour

Varnish is widely known as a primary culprit of equipment failure. This sticky enemy effectively finds its way into most of our equipment and causes operators, maintenance personnel and plant managers a series of nightmares. From unplanned shutdowns costing millions of dollars to sticking of servo valves on startup, or increases in bearing temperature, varnish usually announces its arrival. Once it has been found, there is typically a cause for panic but perhaps it just needs to be understood rather than feared?


The ICML VPR & VIM Badges

Recently (August, 2021), the International Council for Machinery Lubrication launched two new badges. These badges are, VIM (Varnish & Deposit Identification and Measurement) & VPR (Varnish & Deposit Prevention & Removal). These were created after the culmination of 3 years of work from the global varnish test development committee. It has been designed for those involved in all aspects of managing or advising lubricant programs especially those with the responsibility of recommending, selling or installing appropriate deposit control equipment or other mitigation strategies.

Most of the readers will already be familiar with my enthusiasm for understanding lubricant degradation. Thus, when these badges came out, I knew I had to secure them! While the requirements for taking the test suggest the possession of the MLT I or MLA I certification or 1 year of experience, I figured that my MLE certification would be an asset (as I haven’t gotten my MLT I certification yet, it’s on the list!). However, I wanted to make sure that I covered all of the elements in the BoK for both the VIM & VPR badges, so naturally I turned to the varnish guru himself, Greg Livingstone!


Fluid Learning – All the way!

Greg is the CIO at Fluitec but he’s also the facilitator for the ICML VPR & VIM badges. What a treat! If you’ve never heard the name Greg Livingstone then you’re obviously not in the lubrication field. Greg has penned hundreds of papers on varnish and can be thought of as the varnish guru since he has extensive experience in this area. It’s a no brainer that I chose Fluid Learning to get me up to speed on what I needed to know for these exams!

Greg was an amazing facilitator and not only covered information relevant to the BoK for the exams but gave students a full overview about everything you needed to know about varnish. These on demand sessions kept me scribbling notes and nodding to myself and saying, “Oh that’s what really happens!” He presents the information clearly and adds some much needed humour into the sessions. It was an absolute privilege having him as my tutor for these badges.


VPR & VIM- What you need to know!

Varnish Badges_need-to-know

VPR - Varnish & Deposit Prevention and Removal

The VPR badge ensures that candidates understand proactive methods and technologies which can be employed to reduce the degree of degradation. It is also designed to confirm that they can sufficiently evaluate combinations of technologies to prevent and remove varnish including the proper steps to set up and implement an effective varnish removal system.

The topics covered in the VPR include:

  • Problems associated with Varnish & Deposits (20%)
  • Factors affecting Breakdown (28%)
  • Proactive Methods that can be used to minimize oil breakdown (16%)
  • Methods / Technologies that can be used to remove oil breakdown products and/or prevent deposits (36%)

The complete BoK for the VPR badge can be found here.


VIM (Varnish & Deposit Identification & Measurement)

The VIM badge on the other hand is more ideally suited for personnel responsible for recommending suitable oil analysis tests and mitigation efforts related to the deposit tendencies of various in-service fluids (application dependent). They would also be responsible for monitoring and adjusting these strategies accordingly.

The topics covered in VIM include:

  • Problems associated with Varnish and Deposits (20%)
  • Varnish and Deposit Composition (24%)
  • How Breakdown Products / Contaminants become Deposits (24%)
  • Oil Analysis Techniques that can be used to gauge Breakdown and Propensity towards Deposit Formation (32%)

The complete BoK for the VIM badge can be found here.


Exam tips!

Varnish Badges_exam_tips

The actual exams for both the VPR & VIM are set at 45 minutes with 25 multiple choice questions. Candidates must achieve 70% grade to attain the badges. Currently, the fee for the exam is USD75. Since there were overlaps of the content and the exam durations weren’t that long, I decided to sit both exams in one day. I will only advise this for those who are comfortable with doing this as exam anxiety and all that comes along with it can be stressful!

Here are a couple tips for taking these exams:

  • Log into the system 30 minutes prior to your scheduled exam time. This allows you to clear your mind, settle yourself and gives you an extra 15 minutes to figure out where the email is with your credentials! If you can’t remember your password to login to the system, this also gives you enough time to get that reset and sorted before the actual exam time.
  • The session only opens 15 minutes before the appointed time. During this time, you will converse with the moderator as they do the checks of the room and your National Identification. The moderators will engage with you and ensure that you are sitting the correct exam.
  • Ensure you have your National Identification on hand (your passport can be used as well). As long as it has your picture and the expiration date on the same side, it will be acceptable. For the Trinidadians, do not use your National ID card as we have our pictures on the front with the information on the back (I used my Driver’s permit).
  • Candidates have the option of “Flagging” questions to come back to them later. This is a great tool to help you to mark those questions you want to return to or double check.
  • There is a timer in the screen layout which helps you to keep track of your time. 45 minutes passes very quickly when you’re running through the questions!
  • Exam results for these badges come back very quickly as much as within a few hours or one day depending on the time of your exam.

Why do you need these badges?

Varnish Badges_need-badges

As long as you work within the lubrication sector or interface with machines requiring lubrication, then you need to get these badges! Oil degradation occurs throughout the life of the lubricant whether it’s a small or large operation. By understanding how it degrades and ways to mitigate that degradation, you can save your equipment and avoid unwanted downtime. These badges were designed for the personnel in the field to allow them to make decisions regarding the lubricant and to empower them in taking steps to avoid degradation or mitigate it should the need arise. Consider it as getting your passport stamped by the ICML!

The courses offered by Fluid Learning are perfect for those seeking to understand lubrication deposits, what causes them and how they can be mitigated. While the content covered during these sessions align with the ICML VPR & VIM badges, they also add to a more holistic approach to varnish and deposits. Fluid Learning is an official ICML Training Partner and is currently the only one (of which I am aware) offering training prep for these badges. I highly recommend them for anyone seeking to learn more about or avoid sticky varnish situations. 

At the moment of writing this article, there are only 8 people globally who have acquired these badges from ICML. I am the first female in the world to attain these badges but I will not be the only female for very long. Varnish is an issue which affects us all and we need to understand it, so we can prevent it and keep our equipment safe. I hope to see many more candidates with these badges in the near future!



What is Oxidation?

One of the major types of oil degradation is Oxidation. But what is it exactly, as applied to a lubricant?

Oxidation is the addition of oxygen to the base oil of the lubricant to form either of the following:

  • Aldehydes
  • Ketones
  • Hydroperoxides
  • Carboxylic Acids

Wow… too many chemical names right?! These help to pinpoint the conditions responsible and then we can address them accordingly. Each of these by products are produced by different types of reactions or in some cases different stages of the oxidation process. It is key to note the type of by product as it gives us a clue to the root of the issue through which oxidation occurs.

For instance, the presence of Carboxylic acids can result in the formation of Primary Amides which can lead to heavy deposits. Early detection of the Carboxylic acids can help us prevent this. Once we determine the source of oxidation to produce the carboxylic acids, we can in turn remove this from the system.


Oxidation Stages

Oxidation does not happen in an instant. Usually, it follows a series of events which eventually lead to oxidation. Like any process in life, there are different stages for Oxidation:

  • Initiation – Production of the free radical via the lubricant and catalyst.
  • Propagation – Production of more free radicals via additional reactions
  • Termination – Continuation of oxidation process after the antioxidants have been depleted or the antioxidant stops the oxidation process.
Stages of Oxidation

Results of Oxidation

Why is Oxidation bad for the lubricant? What can it ultimately result in?

Well, oxidation can result in the formation or lead up to the following:

  • Varnish
  • Loss of antifoaming properties
  • Additive depletion
  • Base oil breakdown
  • Increase in viscosity
  • Sludge

None of these are good for the lubricant!!!!!!!!! If you see any of these signs be sure to test for oxidation and identify the root cause for the introduction of oxygen in your system.

tests for oxidation

Oxidation Tests

Now that we know more about oxidation… what tests can be performed to prevent it?

There are 6 main tests that can be performed:

  • RPVOT (Rotating Pressure Vessel Oxidation Test)
  • RULER (Remaining Useful Life Evaluation Routine)
  • MPC (Membrane Patch Calorimetry)
  • FTIR (Fourier Transform Infrared)
  • Colour (ASTM D1500)
  • Acid Number (ASTM D974)

One must be careful in selecting which test to apply, this is heavily dependent on the type of lubricant and its application.

For instance, if we perform the RULER test and the antioxidant levels have depleted significantly, we can suspect that oxidation is occurring or has stopped. Charting the rate of antioxidant depletion, can determine the rate of oxidation. This can assist us to forecast the time remaining before antioxidants have been depleted and can no longer protect the base oil.

Thermal Degradation vs Oxidation

What’s the difference between Thermal Degradation and Oxidation of a lubricant?


The two major differences are the contributory factors and the by products that are produced.

For oxidation, both oxygen and temperature are critical to the degradation of the lubricant however, in thermal degradation, the temperature of the lubricant exceeds its thermal stability (usually in excess of 200°C).

Oxidation usually occurs through the release of free radicals which deplete the antioxidants however, Thermal Degradation consists of polymerization of the lubricant.

Oxidation produces aldehydes, ketones, hydroperoxides, carboxylic acids varnish and sludge. On the other hand, Thermal Degradation produces coke as the final deposit.

Lubrication failures in Industrial plants

When failures occur in industrial plants, the first culprit to be suspected is usually the lubricant. However, should this be the first area that one looks at and what are the main causes of the lubricant failing? To understand this, I’ve taken a look at lubrication failures in industrial plants both globally and locally to understand the impact that they have on the sector.

Van Rensselar(1) explained that a recent study conducted by ExxonMobil Lubricants & Specialities of 192 US based power plants, 40% of these have reported issues of varnishing within their facilities. On the other hand; Livingstone, Prescott and Wooton(2) describe a study carried out by EPT Inc which document 44% lubrication failure of gas turbines (not including GE Frame 7FA & EA). It is therefore clear to see that there exists a prevalent issue of lubrication failure within the industry.

When a lubrication failure occurs, it costs an estimate of USD100,000 per trip in a power plant(1). As such, lubrication failures are costly within the industry and methods to reduce issues relating to these types of failures should be explored. Van Rensselar(1) also interviewed Joe Z. Zhou senior research chemist for Chevron Lubricants in Richmond California who explained that one of the main causes of varnish is the primarily oxidized hydrocarbon molecules which undergo surface aggregation and further surface reaction to produce the varnish. However, Livingstone and Oakton(3) add to this description of the main causes of varnish as the oxidation of the oil whereby there is a loss of electrons from the molecules within the lubricant. They go on to state that hydrolysis and thermal degradation are also leading factors for the degradation of the lubricant.             

Van Rensselar(1) explored the main cause of such increased volumes of varnish cases in recent times and found that due to changes in turbine designs to allow for reduced operating and capital costs, the clearances have become smaller, operations are now continuous and a common lubricant for both bearings and controls is now being used. With the reduced clearances, the lubricant can now heat up faster and allow for quicker oxidation occurrences thus leading to varnish. Additionally, with the use of a common lubricant for bearings and control functions, there are significantly different levels of filtration required. Bearings allow for at least a 200-micron filtration system whereas servo valves will accept nothing less than 3-micron filtration(1). As such, it has now become easier for servo valves to become clogged due to varnish as compared to instances in the past.

Case Studies

Johnson, Wooton, and Livingstone(4) describe a case study on a power plant in Arizona, USA where a failure occurred during a routine test. Upon inspection, soft varnish/sludge was found on the trip valve piston. The varnish/sludge was analysed using FTIR testing and its chemical properties suggested the presence of carboxylic acid, primary amide and methacrylate ester. Further investigations revealed that the varnish had accumulated in a uniformed fashion. However, MPC testing did not reveal significant varnish accumulation since these tests were conducted monthly and the varnish had accumulated significantlyduring that time. Upon performing a root cause analysis, it was discovered that a steam leak containing hydrazine gave rise to the presence of ammonia in the system which reacted with the carboxylic acids (produced from oxidation of turbine oils) to form varnish within the system. It was then decided that lower MPC levels were needed to manage the volume of varnish within the system and reduce the steam leaks into the oil. These actions were taken to ensure that the varnish levels could be managed such that there would be no future trips as a result of this issue.

Wooton and Livingstone(5) conducted another case study on a combined cycle power plant in the US which experienced a type of lubrication failure. The plant had been shut down during an outage and it was noticed that when the lubricant storage tank cooled past 32°C large black tar balls formed and floated at the surface of the tank. The filters appeared to contain the black tar when in a liquid form but when allowed to cool, the tar turned into a black / brown solid. FTIR testing on the deposit revealed decomposed amine antioxidant, an ester and an additive not characteristic of the lubricant in service. The non-characteristic additive was identified as a foam inhibitor which was not found in the lubricant in service. It was then concluded, that an incompatible fluid was mixed with the in-service lubricant. A quality control program was implemented to ensure that all the incoming fluids are compatible with the in-service lubricant. As such, for this case study, lubricant degradation occurred due to contamination.

Trinidad & Tobago

After conducting a lubrication survey with turbine users for the period 2014-2015 and it was found that within Trinidad & Tobago, turbine users can be classified into three main categories namely; Power generation, Oil & Gas and Petrochemical. It was found that internationally, there is a greater focus on the Power Generation sector in research regarding lubrication failures. However locally, Power Generation represents 40% of turbine users while Petrochemical represents 34%. On the contrary, it was found that the Petrochemical sector suffered more lubricant degradation issues as compared to the Power Generation sector from this study. Overall, the Petrochemical industry experienced the highest volume of lubricant failures.

Overall, it appears that while Power generation sector has a higher percentage of turbine users, locally the Petrochemical sector emerges as the larger shareholder of lubrication failures in the industrial sector. Given that most of the lubrication failures occurred via oxidation and contamination (both locally and internationally), one can only conclude that within the industrial sector a greater emphasis should be placed on the monitoring of the condition of the lubricants especially for critical equipment. When lubrication failures occur, they can be very costly, as such greater emphasis should be placed on the monitoring of these lubricants in service.


1 Van Rensselar, Jeanna. 2016. “The unvarnished truth about varnish”. Tribology & Lubrication Technology, November 11.

2 Livingstone, Greg, Jon Prescott, and Dave Wooton. 2007. “Detecting and Solving lube oil varnish problems”. Power Magazine, August 15.

3 Livingstone, Greg and David Oakton. 2010. “The Emerging Problem of Lubricant Varnish.” Maintenance & Asset Management, Jul/Aug.

4 Johnson, Bryan, Dave Wooton, and Greg Livingstone. 2013. “Root Cause Determination of an Unusual Chemical Deposit on a Key Oil Wetted Component.” Paper presented at OilDoc Conference and Exhibition Lubricants Maintenance Tribology, OilDoc Academy, Brannenburg, Rosenheim, Germany, United Kingdom, January 22-24, 2013.

5 Wooton, Dave and Greg Livingstone. 2013. “Lubricant Deposit Characterization.” Paper presented at OilDoc Conference and Exhibition Lubricants Maintenance Tribology, OilDoc Academy, Brannenburg, Rosenheim, Germany, United Kingdom, January 22-24, 2013.

How can a lubricant fail?

How can a lubricant fail?

This question has caused many sleepless nights and initiated countless discussions within the industrial and even transportation sectors. Before examining the causes for lubrication failure, one must first consider the definition of lubricant failure.


The composition of a liquid lubricant can be described as a combination of base oil and additives (Menezes, Reeves and Lovell 2013, 295). These two components work in tandem to define particular characteristics of the lubricant to perform its functions. According to Menezes, Reeves and Lovell (2013, 296) the five functions of a lubricant include;

  • the reduction of friction
  • minimization of wear
  • distribution of heat
  • removal of contaminants and
  • improvement of efficiency.

As such, lubrication failure can then be described as the failure of a lubricant to adequately perform any or a combination of its five functions as a result of the degradation of any of its two components; namely the base oil or additive package. Thus, it can be deduced that lubrication failure is as a result of lubricant degradation.

Now that we understand that a lubricant fails when it undergoes degradation which by extension results in the lubricant not being able to perform any of its functions properly, we need to explore further on the types of degradation that exist. Only then can we really answer the question of how a lubricant can fail.

Barnes (2003, 1536) focuses on three main mechanisms of lubricant degradation namely;

  • Thermal Degradation
  • Oxidation and
  • Compressive Heating (Microdieseling).

One may argue that these three types form the basis of all mechanisms of lubricant degradation.


However, Livingstone, Wooton and Thompson (2007, 36) identify six main mechanisms of degradation namely;

  • Oxidation
  • Thermal Breakdown
  • Microdieseling
  • Additive Depletion
  • Electrostatic Spark Discharge and 
  • Contamination.

In this instance, the six identified mechanisms all produce varying identifiable characteristics which lend to these six forming the foundation of identification of lubricant degradation mechanisms. With these six in mind, one would need to be able to determine which degradation mechanism is at work in their facility. Afterwards, methods to treat with these mechanisms must be administered. Firstly, let’s understand each mechanism.


This mechanism involves the reaction of oxygen with the lubricant. According to Livingstone, Wooton and Thompson (2007, 36) oxidation can result in the formation of varnish, sludge, increase in viscosity, base oil breakdown, additive depletion and loss in antifoaming properties of the lubricant.

Barnes (2003, 1536) refers to this phenomenon as the addition of oxygen to the base oil to form:

  • Aldehydes
  • Ketones
  • Hydroperoxides and
  • Carboxylic Acids.
What is Oxidation_
Stages of Oxidation

On the other hand, Wooton (2007, 32) explains that there are three main stages of oxidation namely initiation, propagation and termination. Fitch (2015, 41) explains that:

  • Initiation entails the production of a free radical via the lubricant and a catalyst.
  • Propagation involves the production of more free radicals via additional reactions.
  • Finally, termination entails either the continuation of the oxidation process after the antioxidants have been depleted or the antioxidant stopping the oxidation process.


Livingstone, Wooton and Thompson (2007, 36) have characterized Microdieseling as a form of pressure induced thermal degradation. They describe it as the transition of entrained air from a low pressure to a high pressure zone which results in the adiabatic compression.

This type of compression results in localized temperatures almost on excess of 1000°C.As such, the lubricant undergoes dramatic degradation. Wright (2012, 14) explains that because of these high temperatures, the bubble interface becomes carbonized. As such, carbon by products are produced and the oil undergoes oxidation.


Electrostatic Spark Discharge

Livingstone, Wooton and Thompson (2007, 36) describe this phenomenon as the generation of static electricity at a molecular level when dry oil passes through tight clearances. It is believed that the static electricity can build up to a point whereby it produces a spark. This spark can induce localized temperatures in excess of 10,000°C which can significantly degrade the lubricant at an accelerated rate.

Van Rensselar (2016, 30) also advocates that Electrostatic Discharge contributes to the formation of free radicals in the lubricant which subsequently results in uncontrolled polymerization. This polymerization of the lubricant gives rise to the formation of varnish and sludge which may deposit on the surface of the equipment or remain in solution. Van Rensselar (2016, 32) indicates that the most common result of Electrostatic Discharge is an elevated rate of fluid degradation and the presence of insoluble materials.

Thermal Breakdown

This mechanism is largely dependent on temperature as one of its contributory factors even though dissipation of heat was highlighted above as one of the functions of a lubricant. However, during the operation of machinery particular components tend to develop increasing temperatures.

As described by Livingstone, Wooton and Thompson (2007, 36) once this temperature exceeds the thermal stability point of a lubricant, the consequences can include shearing of the molecules. This phenomenon is also called the thermal cracking of the lubricant which can result in the production of unwanted by products, polymerization and decrease in viscosity.

Subsequently, Barnes (2003, 1536) explains that thermal degradation usually occurs when the lubricant experiences temperatures in excess of 200°C. He also states that the by-products of thermal degradation differ from that of oxidation.

Wooton and Livingstone (2013) state that there are two main actions that can occur once a lubricant is thermally degraded.

  • Either the small molecules will become cleaved off and volatize from the lubricant. This does not leave any deposit in the lubricant.
  • On the other hand, there is the condensation of the remainder of the molecule in the absence of air thus dehydrogenation also occurs. Consequently, coke is formed as the final deposit with numerous types of deposits forming between the start of the condensation to its final deposit of coke.

The main contributing factor for thermal degradation can therefore be linked to dramatic increases in temperature or constant high temperatures.

Additive Depletion

Wooton and Livingstone (2013) indicate that additive depletion can result in either organic or inorganic deposits. The nature of the deposit is dependent on the type of additive that has been depleted and its reaction with other components in the oil.

For instance, if the rust and oxidation additives drop out of the oil, they typically react to form primary antioxidant species thus producing organic deposits. However, as Wooton and Livingstone (2013) explain, inorganic deposits can also be formed from additives that have dropped out of the oil but did not react with anything. This unresponsive reaction is typical of ZDDP (Zinc dithiophosphate) which is an additive that assists with reducing wear in the lubricant.

In cases of additive depletion, the FTIR test seeks to identify spectra relating to the reacted or unreacted additive packages for the lubricant in use (Wooton and Livingstone, 2013).


This mechanism of degradation can include foreign material entering the lubricant and being used as catalysts for degradation mechanisms listed above. Contaminants can include a variety of foreign material, however Livingstone, Wooton and Thompson (2007, 36) have narrowed the list to metals, water and air. These main contaminants can significantly contribute to the degradation of the lubricant by oxidation, thermal degradation or compressive heating.

From the above, we can summarize these lubricant degradation mechanisms into the following table:

From this summary, we can now assess the methods in which a lubricant can fail. While this article may serve as a guide in determining various lubricant degradation mechanisms, each mechanism must be treated differently depending on the conditions (environmental and operational) that exist during the lubricant failure. A proper root cause analysis should always be done when investigating any type of failure.


1 Livingstone, Greg, Dave Wooton, and Brian Thompson. 2007. “Finding the Root Causes of Oil Degradation.” Practicing Oil Analysis, Jan – Feb.

2 Barnes, M. 2003. “The Lowdown on Oil Breakdown.” Practicing Oil Analysis Magazine, May-June.

3 Livingstone, Greg and David Oakton. 2010. “The Emerging Problem of Lubricant Varnish.” Maintenance & Asset Management, Jul/Aug.

4 Wooton, Dave and Greg Livingstone. 2013. “Lubricant Deposit Characterization.” Paper presented at OilDoc Conference and Exhibition Lubricants Maintenance Tribology, OilDoc Academy, Brannenburg, Rosenheim, Germany, United Kingdom, January 22-24, 2013.

5 Van Rensselar, Jeanna. 2016. “The unvarnished truth about varnish”. Tribology & Lubrication Technology, November 11.