Q: What does FZG mean and why do gear oils have a rating?
FZG stands for “Forschungsstelle für Zahnräder und Getriebebau”, Technische Universität München (Gear Research Centre, Technical University, Munich), Boltzmannstraße 15, D-85748 Garching, Germany.
There are several FZG tests and these vary to establish different things. We will explore the two most common tests and what they mean.
The FZG tests were designed to accurately determine the types of gear failures that were influenced by scuffing, low speed wear, micropitting and pitting1. While there are load other tests for gear oils (such as Timken OK test) these do not accurately identify the actual failure stages that gears experience.
One of the most commonly used FZG test is the FZG A/8.3/90 according to DIN ISO 14635-1. This is mainly used for evaluating the scuffing properties of industrial gear oils2. What do the numbers in the test mean?
The “A” represents an A-type gear with Pinion face width = 20mm, center distance = 91.5mm, number of teeth (pinion) = 16, number of teeth (gear) = 24. These are used in the test and are loaded stepwise in 12 load stages between Hertzian stress of pC= 150 to 1800N/mm2.
The “8.3” represents the pitch line velocity of 8.3m/s in which the gears are operated for 15 minutes at each load stage.
The “90” indicates the starting temperature of the oil (90°C) in each load stage under conditions of dip lubrication without cooling.
After each load, the gear flanks are inspected for scuffing marks. However, the fail load stage is determined when the faces of all pinion teeth show a summed total width of damaged areas which is equal or exceeds one tooth width. In the gravimetric test, the gears are dismounted and weighed to determine their weight loss.
The FZG A10/16.6R/90 on the other hand is used for automotive gear oils (GL4). It is the standard FZG gear rig test but the speed, load, load application and sense of rotation have been slightly altered.
The “A” represents an A-type gear however, these now have a reduced pinion face width to 10mm (from 20mm above).
The “16.6R” represents the increased speed of the pitch line velocity of 16.6m/s in which the gears are operated for 15 minutes at each load stage in a reversed sense of rotation.
The “90” indicates the starting temperature of the oil (90°C) in each load stage under conditions of dip lubrication without cooling.
However, the FZG S-A10/16.6R/90 is the shock level test done for the GL5 oils. In this test the gears are directly loaded in the expected load stage and a PASS or FAIL is issued.
ISO 14635-1:2000 Gears- FZG test procedures- Part 1: FZG test method A/8,3/90 for relative scuffing load carrying capacity of oils.
Test methods for Gear lubricants. Bernd-Robert Hoehn, Peter Oster, Thomas Tobie, Klaus Michaelis. ISSN 0350-350X GOMABN 47, 2,129-152 Stručni rad/Professional paper UDK 620.22.05 : 621.892.094 : 620.1.05
Ever since the MLE (Machinery Lubrication Engineer) exam was launched in April 2019, I was intrigued by it! It provided a certification where the dynamic duo of reliability and asset managers could be combined and infused with elements of lubrication and oil analysis. The perfect combination! However, since its launch, there have only been a couple of public sittings where the exam has bene conducted. Unfortunately for me, this would have required me to travel to the US for at least a week and run my business remotely. Every session that was announced directly clashed with my schedule and it was almost impossible for me to attend a session that didn’t clash with my crazy schedule.
Enter the C-19 pandemic that we’ve been facing that began in March 2020 (for us in Trinidad when our borders were closed). This pandemic caused (some much needed) downtime for all of us and helped to revolutionize the industry by allowing advancements in technology to finally be accepted. During the downtime, I decided to start studying for the MLE Exam with 5th Order Industry LLC. What a surprise, I had in store for me! After starting the course, I realized, I knew nothing about lubrication in the past! It was a definite eye opener and made me aware of the number of elements that I took for granted during my entire lubrication career.
Michael Holloway CRL, LLA (I,II), MLT (I,II), MLA (I,II, III), OMA, CLS, MLE was a great teacher and offered me assistance in all the areas in which I was unclear. He was also extremely responsive to all of questions at weird hours of the day when I got the time to study for the exam. His guidance was paramount to me achieving the MLE certification! The flexibility of On Demand modules allowed me to learn at my own pace and ensure that I understood each area before moving on to the next. The unique style of the delivery of the class really ensured that I benefitted from the bulk of the information provided as it allowed me to apply the knowledge in real life practical situations.
What exactly is the MLE?
The MLE exam was launched in April, 2019 along with the ICML 55.1 standard. Part 1 of the ICML 55 standard speaks to Asset Management, requirements for Optimized Lubrication of Mechanical Physical Assets. The MLE was mapped to this ICML 55.1 standard. This allows personnel within organizations who are studying for this exam to become more prepared for eventually attaining the ISO 55001 certification for their organization. The ICML 55.1 standard was drafted using the ISO 55001 as a guide however the 55.1 standard fills the gap with specific requirements and guidelines to establish, implement, maintain and improve consistent lubrication management systems and activities.
The MLE Body of Knowledge consists of 24 areas of knowledge and can be found here in greater detail. Additionally, the well documented Domain of knowledge is also accessible here.
The 24 areas for the BoK include:
Asset Management, ISO 55001 & ICML 55; Basic Elements (3%)
Machine Reliability; Basic Elements (5%)
Machine Maintenance; Basic Elements (5%)
Condition-based Maintenance; Basic Elements (5%)
Tribology, Friction, Wear and Lubrication Fundamentals; Basic Elements (5%)
Lubricant Formulation for Machine Types to achieve Optimum Reliability, Energy Consumption, Safety and Environmental Protection; Basic Elements (5%)
Job and Task Based Skills / Training related to Lubrication and Reliability by User Organizations (4%)
Lubrication Support Facilities needed in Plants and Work Sites (3%)
Risk Management for Lubricated Machines; Basic Elements (4%)
Optimum Machine Modifications and Features Needed to Achieve and Sustain Reliability Goals (5%)
Lubricant Selection for Optimum Reliability, Safety, Energy Consumption and Environmental Protection based on Machine Type and Application (4%)
Lubrication related Planning, Scheduling and Work Processing (4%)
Periodic Lubrication Maintenance Tasks (4%)
Inspection of Lubricated Machines for Optimum Reliability, Safety, Environmental Protection and Condition Monitoring (5%)
Lubricant Analysis and Condition Monitoring for Optimum Reliability Objectives (8%)
Fault/Failure Troubleshooting, Root Cause Analysis (RCA) and Remediation (5%)
Supplier Compliance / Alignment and Procurement of Services and Products (3%)
Waste and Used Lubricant Management and Environmental Compliance (3%)
Energy Conservation and Environmental Protection (3%)
Lubrication during Standby, Storage and Commissioning (2%)
Program Metrics (5%)
Continuous Improvement (4%)
As per ICML, candidates require at least 5 years education (post-secondary) or On-the-Job training in one or more of the following fields: Engineering, Mechanical Maintenance, Maintenance Trades, Lubrication, Oil Analysis and / or Condition Monitoring (Mechanical Machinery).
There are no prerequisites of an Engineering Degree or prior ICML certifications to attain the MLE certification. However, there are overlaps in the BoKs for the MLA & MLT exams that would prove useful in preparing for the MLE exam.
Scheduling the Exam
Once I completed the course from 5th Order Industry, I was awarded my Certificate of Completion which stated that I had achieved the required 40 hours of preparation for the exam. Looking back on it now, I spent a lot more than 40 hours preparing for the exam! In addition to completing the courses online, I started reading documents, manuals and books all outlined in the Domain of Knowledge (mentioned above).
In essence, it took me approximately 3 and a half months to fully prepare for this exam! It’s such a lengthy time span since I was studying at my own pace which the On Demand modules allowed me to do and I wanted to make certain that I was ready! After completing the online courses, it took me an additional week to schedule my exam as I had to make sure that there would be no urgent order of business during my 4 hour isolation and that I had reviewed at least 5 times the material covered!
To schedule the exam, one has to go to the ICML site. Then choose the mode of delivery (I chose Online of course and not Paper based). The site then allows you to choose the exam that you are applying for while giving you the guidelines that are specific to the exam type chosen (Online or Paper Based). For the Online sessions, they allow the candidates to verify whether their computer meets the requirements by clicking on some links provided.
After the exam type is selected, the candidate is moved to another page where they are required to provide some confirmations and upload their training certificate from one of the approved training providers. After submitting this information, the candidate is then directed to another page to fill out their profile information and make payment. An email will be received with the receipt from ICML. Afterwards, you will receive another email from Examity providing a link to fill out your profile and schedule your exam.
The MLE exam spans a duration of 4 hours. These can pass in the blink of an eye in the exam room! For the exam, be sure to login at least 15 minutes before the scheduled time of your exam. Bring along a form of National Identification (ensure that the expiry date is on the same side as your picture). In my case, my National ID card has my picture on one side and all the details on the other side. The Proctor had to ask me for another form of ID and since my Passport had expired (the renewal date passed during the Quarantine Period!), I had to use my Driver’s permit which was upstairs! It took a bit of shuffling around (frantically, I’ll say!) but the Proctor was able to use my Driver’s permit after I retrieved it.
The desk area must be clean with no additional items. The only items on my desk were my 2 forms of ID. The Proctor will ask to view the entire room and ensure that all doors are closed. There is no need to walk with a calculator as one will be available in the virtual exam room on the screen as well as other tools that may be required. For this exam, you just need to walk with your brain, selection skills and your virtual knowledge base! The exam allows candidates to flag questions that they are unsure about and come back to them at a later time (which was absolutely terrific for me)!
After completing the exam, the candidate has to inform the Procter that they have finished and then submit their answers. Thereafter begins the dreaded wait for the results! To my surprise, I got these results in two days after completing the exam! I can tell you, there was a lot of hesitation before opening that email! The email contained the results (yes I did pass! Yay!) and the score for each of the 24 sections of the exam.
At the time of writing this article, I am the first MLE in the entire Caribbean (I had to check twice to make sure)! I would highly recommend the MLE exam for lubrication professionals who want to challenge themselves and personnel within the reliability and asset management sectors who have a passion for lubrication. It is a wonderful exam and the knowledge that it will expose you to will be phenomenal!
Quite often, when lubrication failures occur, the first recommended action is to change the lubricant. However, when the lubricant is changed, the real root cause of the lubricant failure has not been solved. As such, the cause of lubrication failure will continue to be present and may escalate further to develop other problems.
Essentially, this can cause catastrophic future failures simply because the root cause was not identified, addressed and eradicated. Moreover, the seemingly “quick fix” of changing the lubricant, is usually seen as the most “cost effective” option. On the contrary, this usually becomes the most expensive option as the lubricant is changed out whenever the issue arises which results in a larger stock of lubricant, loss in man hours and eventually, a larger failure which can cost the company at least a month or two of lost production.
In this article, we investigate lubricant failures in Ammonia plants and their possible causes. Some Ammonia plants have a developed a reputation for having their product come into contact with the lubricant and then having lubrication failures occur. As such, most Ammonia plant personnel accept that the process materials can come into contact with the lubricant and usually change out their lubricants when such issues occur. However, there are instances, where the ammonia is not the issue and plant personnel needed to perform a proper root cause analysis to determine the root cause and eradicate it. Here are a couple of examples of such instances.
Livingstone (1) defies the Lubrication Engineers Handbook in their description of ammonia as an inert and hydrocarbon gas that has no chemical effect on the oil, stating that this is incorrect. Instead, Livingstone (1) lists the number of ways that Ammonia can react with a lubricant under particular reactions such as;
ammonia being a base that can act as a nucleophile which can interact with any acidic components of the oil (such as rust/corrosion inhibitors)
reaction of ammonia with carboxylic acids (oil degradation products) to produce amides which cause reliability issues
transesterification of any ester containing compound to create alcohol and acids and the reaction of ammonia with oxygen to form NOx which is a free radical initiator that accelerates fluid degradation.
As such, one can firmly establish that ammonia influences the lubricant and can lead to lubrication failures should that be the cause of the lubricant failure.
The Use of Root Cause Analysis
Van Rensselar (2) quotes Zhou as saying the best method for the resolving varnish is to perform a root cause analysis. Wooton and Livingstone (3) also advocate for the use of root cause analysis to solve the issue of varnish. They go on to explain that the characterization of the deposit aids in determining the root cause of the lubricant degradation. As such, Wooton and Livingstone (3) have developed a chart to assist in deposit characterization as shown below.
Wooton and Livingstone (3) discussed that with the above figure, once the deposit can be characterized then the type of lubricant degradation can be more accurately identified. As such, the root cause for the lubricant degradation can now be firmly established thereby allowing solutions to be engineering to control and reduce / eliminate lubricant degradation in the future.
A case study from Wooton and Livingstone (3) was done with an Ammonia Compressor in Romania which experienced severe lubricant degradation. In this case study, they found that when the in-service lubricant was subjected to two standard tests namely MPC and RULER, both tests produced results within acceptable ranges. As such, there was no indication from these tests that the lubricant had undergone such drastic degradation as evidenced by substantial deposits within the compressor. Thus, it was determined that the deposits should be analysed as part of the root cause analysis.
For the deposits from the Ammonia compressor, Wooton and Livingstone (3) performed FTIR spectroscopy to discover that its composition consisted of mainly primary amides, carboxylic acids and ammonium salts. It was concluded that the carboxylic acids formed from the oxidation of fluid while in the presence of water.
In turn, the carboxylic acids reacted with the ammonia to produce the primary amides. These amides consisted of ammonium salts and phosphate. As such, the onset of carboxylic acids within the system eventually leads to the lubricant degradation. Thus, an FTIR analysisfor carboxylic acids was now introduced to this Ammonia plant as well as MPC testing to monitor the in-service lubricant.
Additionally, chemical filtration technology was implemented to remove carboxylic acids within the lubricant. These two measures allowed for the plant to be adequately prepared for lubricant degradation and avoid failures of this type in the future.
Another case study was done in Qatar with an ammonia refrigeration compressor which was experiencing heavy deposits due to lubrication degradation. For this Ammonia plant, high bearing temperatures and deposits were found on the bearing.
Upon investigation, it was realized that the lubricant had been contaminated externally and there was restricted oil flow to the bearings. After a FTIR was performed it was deduced that that the deposits were organic in nature and there were several foreign elements including high levels of carbon and primary amides.
From further root cause analysis, it was determined that the high temperatures observed were due to the lubricant starvation. Due to these high temperatures, oxidation initiated and with the high levels of contamination (mainly from ammonia within the process) this lead to degradation of the lubricant in the form of heavy deposits.
The bearing oil flow was increased and reduction in external contaminants were implemented. Oil analysis tests of Viscosity, Acid Number, Membrane Patch Calorimetry and Rotating Pressure Vessel Oxidation tests were also regularized in the preventive maintenance program. Thus, for this failure, some operational changes had to be made in addition to increased frequencies of testing. With these measures in place, there would be a reduced likelihood of future failures.
From the case studies mentioned, it can be concluded that ammonia systems have a higher possibility of undergoing lubricant degradation due to the contamination of the lubricant by ammonia gas / liquid due to its properties. However, it must also be noted that the ingression of ammonia into the lubrication system is not the only cause for lubrication failure.
Therefore, it is imperative that a proper root cause analysis be carried out to determine the varying causes for lubrication failure before the ingression of ammonia accepts full responsibility for any such failure.
Livingstone, Greg (Chief Innovation Officer, Fluitech International, United States America). 2016. E-mail message to author, March, 08.
Van Rensselar, Jeanna. 2016. “The unvarnished truth about varnish”. Tribology & Lubrication Technology, November 11.
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.
Peter Horsburgh has essentially captured the 5 Habits of an Extraordinary Reliability Engineer in his book! His style of writing appeals to engineers as he keeps the content directly on point and provides case studies to each of his chapters. Most engineers aren’t big readers (except for manuals and when absolutely necessary) but the conversational tone in which Peter explains some of his revelations about the industry ideally captures the attention of reader. I couldn’t put the book down once I started reading it!
What I really love about this book is that it was holistically designed for engineers. The book is small allowing persons to carry it around anywhere and it isn’t too thick to daunt the reader into thinking that they need to allocate a couple of days to reading it. Peter has kept the chapters short, driving the various points home and has even provided summaries for each section of the book. This makes it super easy when trying to relate to an issue that he has discussed. Peter has also done an excellent job with the illustrations in the book to keep the reader’s attention and provide for some light amusement to keep the book as a guide that engineers want to return to time and time again
Additionally, an extra step was taken to ensure that the book has some durability built into it. The pages aren’t the ordinary soft paper, rather the pages have a bit of a card stock finish. This was my first light bulb moment after opening the book (there were tonnes more light bulb moments while reading it!). Obviously the pages had to be durable! This book was meant to be in the workshop with the engineers becoming part of their manuals! I can clearly see engineers rushing back to this book during the course of the day to get back to a particular chapter or case study that can assist them in some issue of the day.
I definitely enjoyed this book! Peter first introduces the reader to the 5 Don’ts of Reliability Engineering. I hadn’t realized until then that the “Don’ts” that were covered form critical parts of any Reliability Engineers’ day! The manner in which he introduces these stood out for me, as he brought in case studies to demonstrate instances where he dealt with some of these “Don’ts” or even performed them himself. It is with these case studies that I appreciated that some of the situations that I face daily may receive a “Don’t” when it shouldn’t. With Peter’s story telling ability, he was able to truly relate to the readers the practical examples of things that should and shouldn’t be done. Unlike other books, he demonstrates the impacts (and throws some financials in there as well, which helps us to actually quantify what we’re looking at) of particular “Don’ts”.
Right after the “Don’ts” section, he launches into the “5 Habits” which are each covered in their own Chapters. While he explains the habits in this section, he then further dedicates each Habit to a Section (not just a Chapter) where he mixes in his real life experiences as his Case Studies while providing introductory information on the habits and their impacts on the plant and its reliability. Quite skilfully, afterwards he dedicates a Section to “Applying the habits”. This is in keeping with the conciseness of the book!
I would highly recommend that all Reliability Engineers add this book to their library! It’s a book that gets all the lightbulbs blinking in your head from the moment that you begin reading it. However, it is not a book to be read just once, it needs to form part of your routine (either weekly or monthly). After reading this book, I can almost guarantee that the week that you spend in work afterwards will be nothing short of interesting as you may find yourself thinking… “Peter covered this in his book…let me just look back and verify if this can be dealt with in another way”. That being said, I believe that any engineer will make it part of their “consultation” guide especially during brainstorming sessions. It was indeed a pleasure reading this book!
Root Cause Analysis has always been dear to my heart. The procedure involved in finding the root causes and addressing them have intrigued me greatly as it involves using all your data gathering and cognitive skills. In the past, it was a bit difficult to properly perform RCAs since it usually meant jumping around different types of software. For instance, depending on the type of analysis that I wanted carry out, I would either use a Fish Bone Diagram or Cause and Effect Logic Tree. Depending on the type that I needed to use, I would have to switch programs just to get these generated. Then, there’s the issue of writing the final report and utilizing my expert copy and paste skills with Microsoft word while toggling excel worksheets to determine the costs attached to the failure.
Needless to say, I was very impressed when introduced to the PROACT software. It has an extremely friendly user interface (in some cases, I can even use drag and drop options!) which is very easy to navigate even for a beginner like me at the time. What I really love about the software is that it bridges the gaps and guides users (both for beginners and experts) on the RCA process. By allowing users to follow a step a by step processit ensures that users don’t forget vital pieces of information that are absolutely critical to the RCA.
If you are familiar with RCA, you will be aware that the basis of any RCA is properly establishing the Severity of the failures. As such, the first step when the user enters the software, is the assigning of the Severity of the failure with the Severity Calculator. This calculator can even be customized for varying applications! Afterwards, the profile of the failure is then defined. This profile allows the user to identify elements that may have been forgotten if the RCA was being done from scratch. The Severity Calculator also allows users todetermine the type of analysis that is fit for the severity index. Depending on the severity, the user can be guided to use either; 5 Whys, Fish Bone Diagrams or Cause and Effect Logic Trees. This is definitely one key advantage since it allows for different forms of analysis based on the severity.
Next the Critical Success Factors are inserted. The strategic placement for the input of these factors at this point in the analysis is purely genius! It forces the user to determine which factors directly impact them and these are usually placed on the final report. These CSFs start shaping the pending RCA into the mould that we need. Once these CSFs are established, then the objectives need to be defined. These help the analyst in guiding their RCA and ensuring that it is kept focused. It is easy to become distracted when performing these types of analyses since users are presented with an abundance of information. The definition of these aspects help the analyst to keep on track.
As with any RCA, there must be a team involved. The PROACT software allows users to delegate different tasks to different team members! It can even track the status of these events. Instead of sending long reminder emails (which tend to choke one’s inbox and can be easily missed), it is essentially easier to view the status of the assigned tasks using the PROACT software. This is a definite advantage of the software!
Now to the core of the software, the development of the RCA! Users are allowed to define the event that lead to the failure. Here’s where the software gets very interesting!!! Users can pull from existing templates dependent on the type of failure! This is the highlight of the PROACT software for a user like myself! It is very interesting to view templates (there are over 300 templates) of common failures and compare these to what the user has actually experienced. It allows the user to be able to access years of experience of a consultant at their fingertips! The team at Reliability Center Inc have definitely put a lot of work into developing these templates and have drawn upon their actual field experience for the past30+ years! This is the absolute game changer for the software!
During the building (or growing) of the Cause and Effect Tree, the user is allowed to authenticate their hypotheses and can attach pictures from the failure as verification for ruling out or accepting that mode as one of the root causes. These pictures can then be input into the final report without the need for cropping, cutting and pasting and all the exciting formatting issues that tend to occur when trying to include pictures in the final report.
PROACT also allows for users to input financial data. Another game changer for me! Users can define the costs associated with the downtime for particular failures, repair costs or even manpower costs. These all help to put a financial value on the cost of the failure being investigated. This neat trick is crucial for the review by upper management! Additionally, the final steps in any of the RCAs is to determine recommendations for the latent causes that were determined. These will be the courses of action to be taken to prevent failures of this nature from occurring in the future.
Overall, the PROACT software is indeed a time saver, keeps excellent track of the findings and collections of the investigation at hand and produces a very succinct, detailed report that anyone from upper management to the engineers can clearly understand. I love working with this software and my clients are always very impressed that this type of software actually exists and is so easy to use! I would highly recommend any user (novice or expert) in the reliability field to use the software in their everyday tasks and realize the impact that it has on increasing the efficiency of RCAs and their ROIs to their organizations.