Over the years, I have come across instances where issues have arisen, such as the filters blinding prematurely.  With testing, this has ultimately been identified as leaving the tank open in a paper mill, and an investigation of the elements highlighted this, along with the high particle counts. 

There have been other root causes, such as mineral oil being added to a phosphate ester oil on an electro-hydraulic control system, or, in another case, the oil supplier putting engine oil in drums intended for turbine oil.  In the latter case, within less than an hour of topping up the turbine tank with just one of the mislabelled drums, the filters were showing as blocked, and the turbine was out of service for six months.

Within less than an hour of topping up the turbine tank with just one mislabelled drum, the filters were blocked, and the turbine was out of service for six months.

A more confusing scenario was a switch in supplier for a bearing oil at a paper mill.  The end-user was assured of compatibility, but it transpired that a difference in the additive package, combined with water ingress (it was a paper mill after all), led to deposits on the filter.  This could so easily have been checked by a filter-compatibility test from the new oil supplier.  Filter companies often offer this service as well.

Consequently, I tend to use the following checklist when clients experience sudden, premature filter blockages in a previously stable system.

In the first instance, however, it is always useful to ask what the last maintenance action was, as this is often the cause or at least a clue to the possible cause. 

While a number of these were major incidents involving high costs, I still frequently encounter the “oil is just oil” issue, and top-ups on smaller machines have been made with the wrong oil.

I still frequently encounter the “oil is just oil” issue, and top-ups on smaller machines have been made with the wrong oil.

Typically, I might get a phone call along the lines of “Is it possible to see if the wrong oil has been used for a top-up?”  To which my answer is always, “Let me guess, you found the wrong container next to the asset?”  Invariably, the answer is always yes. 

Field Checks Before the Lab

So, when it comes to testing for the wrong oils used as top-ups, before even considering a laboratory test, there are a few basics to consider first.

What the Lab Results Reveal

When it comes to laboratory testing, ideally, two samples need to be sent: a sample of the correct oil from a container in the store, along with the suspect sample from the asset.  Using a sample of the correct oil, fresh from a container, a reasonable baseline for inorganic additive levels can be established and used for comparison with the suspect oil.

In terms of testing, however, apart from the obvious chemical and physical properties, measured wear rates may be affected by incorrect oil, which will elevate the measured wear metals. 

Ultimately, though, several lessons spring to mind that we would do well to remember:

1. Training and raising awareness of the need to avoid cross-mixing oils
2. The use of a color code system for lubricants, with the color code visible on the new containers in stores, on handling equipment, and on assets.
3. Guarantees backed up by insurance coverage from the suppliers when switching lubricant brands, but ideally, with technical testing.
4. Certificates of conformity for all new batches of lubricants supplied.
5. Random sampling of new oils, particularly for the high-cost assets.

When the lube room resembles a crime scene – chaotic storage, unlabeled containers, questionable handling tools, inconsistent transfer practices – it becomes a hidden driver of accelerated wear, additive depletion, ingress-driven contamination, and component life variability that will never show up cleanly in maintenance reports.

The condition of the lube room often mirrors the true reliability culture more accurately than any KPI dashboard. These conversation starters expose the systemic, upstream issues that quietly undermine asset reliability long before oil ever reaches a machine.

25 Lube Room Conversation Starters

1. Why do unlabeled or ambiguously labeled containers still circulate – and who verifies contents before use?
2. What process ensures transfer equipment is flushed, capped, and stored correctly to maintain cleanliness targets per the ISO 4406 cleanliness standard?
3. Why does incoming oil fail our cleanliness specifications – and are we actually verifying ISO 4406 codes instead of relying on supplier paperwork?
4. Who is accountable for lubrication storage standards – and why is “nobody” still the default?
5. Are lubricants grouped by base oil, viscosity grade, and additive chemistry – or simply by whichever shelf is empty?
6. Why are new desiccant breathers sitting idle while storage containers exchange unfiltered air?
7. Why are open funnels or unsealed top-off containers still acceptable when they are proven contamination pathways?
8. If drums are stored horizontally, are the bungs positioned at 3 and 9 o’clock to maintain seal integrity?
9. Do we routinely verify incoming lubricant quality (particle count, viscosity per ASTM D445, AN/BN) against the OEM Certificate of Analysis – or assume delivered product meets specification?
10. Why is moisture control reactive when water accelerates oxidation, depletes additives, and destabilizes boundary films?
11. Have we consolidated lubricant options to the lowest reasonable minimum?
12. Why is the filter cart treated as an emergency tool instead of being used as part of a repeating task to filter all critical sumps routinely?
13. How often do we audit lubricant shelf life – especially for products nearing manufacturer-recommended limits (typically 2–5 years depending on chemistry and storage conditions)?
14. What ISO 4406 cleanliness code targets do we require for stored lubricants – and do we confirm incoming product meets those targets before use?
15. Are grease cartridges stored to prevent temperature cycling and oil separation – or do we assume the sealed packaging eliminates all risks?
16. What controls prevent “clean” top-off containers from becoming contamination sources after weeks of exposure?
17. Why is faded Sharpie still our primary labeling method instead of standardized, controlled identification?
18. Do we maintain a documented lube room SOP – or rely on tribal knowledge that evaporates with personnel turnover?
19. Why do spills persist long enough to become permanent floor features despite OSHA 1910.22 housekeeping requirements and slip-risk implications?
20. Why do we allow partially used containers to sit uncapped, accelerating airborne particulate ingress?
21. How many lubrication-related failures begin right here in the lube room long before a technician touches a machine?
22. Are the open-stores containers protected from temperature extremes, high atmospheric pollution, and high humidity to help maintain additive stability and prevent condensation?
23. What is our process for removing expired or degraded lubricants – before they become “mystery blends” applied during outages?
24. Is the lube room organized as a contamination-control system – or just as a more efficient way to store lubricants?
25. If a new hire walked in today, would the lube room reinforce excellent lubrication practices – or accelerate the spread of bad habits?

A modern lube room isn’t a storage closet – it’s a contamination-control and quality-assurance environment. When lubricants are stored under controlled conditions, verified for cleanliness, transferred with discipline, and protected from environmental stressors, machine reliability increases before any wrench is turned.

Cleaning up the lube room is not cosmetic work; it’s one of the highest-leverage steps a plant can take to stabilize lubrication quality, extend asset life, and reduce avoidable failures. These conversation starters expose the upstream weaknesses that sabotage reliability – and point the way toward transforming the lube room into a controlled, engineering-grade operation.

As with many things in lubrication, sometimes too much is as bad as too little.

This is certainly the case with filtration. 

How Fine Is Too Fine for Your Oil Filter?

To answer that, we need to look at several factors.

First, let’s dispel a few myths about fine filtration and the perceived problems it can create.

“My oil analysis report showed a huge drop in additive elements after fitting finer filters.”

The perception here, of course, is that fitting the fine filters has removed much of the additive package.  This is not the case.  Before fitting the fine filters, a large quantity of solid material, including wear metals and depleted additives, would cling to these particulates.  The spectral analysis will still detect these elements even though the additive is no longer of use. 

After fitting the finer filters, much of this material is removed and no longer detected in the oil sample, allowing the proper level of fresh, available additive to be more clearly shown.

All of that said, there are several instances where caution is required regarding additive separation from barrier filtration.  The following three additives are of most concern. In order of decreasing concern:

• Solid suspension EP additives such as Molybdenum Disulphide or graphite that can be up to 40µm in size. This is usually only applicable to gear oils, and in these instances, it is unlikely that filtration is even applied. More to the point, the lubricant supplier will usually provide warnings in this regard with these oils in the product data sheet.
• Defoamants work in various forms, but Silicon in its supersaturated state, as microscopic globules, can be up to 10µm in size. This is a concern with hydraulic systems, where there is a tendency to want the finest filter possible.
• Viscosity Index Improvers swell when subject to the oil warming and, as such, can potentially be caught in the filter. However, being soft in nature, they do typically make their way through.

Generally, additives are much more at risk from decomposition driven by water, heat, oxygen, and reactive solids such as wear metals, or from poor storage in extreme ambient temperatures over longer periods.

“Fitting finer filters will simply result in shorter element life, and the cost will be significantly higher.”

The assumption here is that the finer filter will be working harder, which is true initially. However, after the cleanup period, the removal of the previous high levels of particulate will reduce the wear rate, resulting in less work for the finer filter.  Additionally, better quality system filters with a finer rating typically use synthetic fibres, which often have a higher dirt holding capacity than cheaper elements of a coarser rating.

Indeed, though, there is no point in fitting better filtration without first taking steps to prevent the ingress of solids, such as uprating the breather, seals, and gaskets, and improving the transfer and storage practices.  Remember, it is easier to keep dirt out of the oil than to remove it from the oil.

“Surely fitting finer filters will impact the pressure delivery to the machine.”

Obviously, assessing the pressure drop across the filter is essential. Indeed, it may be necessary to increase the filter housing dimensions or to put two filters in parallel to maintain the correct differential pressure.  However, as mentioned above, better quality system filter elements with synthetic fibres smaller than those in cheaper elements will have less restriction to the oil flow. Thus, the pressure drop is less affected.

Key Factors That Define When a Filter Is Too Fine

Target cleanliness levels to achieve the desired reliability.

This means we need to look at the following issues:

• Machine type – what clearances are we dealing with, and how susceptible is the machine to solid particle damage?
• Ambient conditions – how dusty is the environment, including not just from the process, but also geographically and with respect to the weather and winds.
• Lubricant type – particularly with respect to the additive package restrictions.

Machine Type Considerations

In order of cleanliness needs, gearboxes are the least concern since with their hardened surfaces and the typically higher viscosity oils, they are reasonably tolerant of particulate and therefore, while they do undoubtedly benefit from cleaner oil, the need for extreme fine filtration is unlikely and consequently, something like a ß₁₀ > 1,000 is often sufficient.

While engines will benefit from cleaner oils than gearboxes, there is the added pressure of the soot loading.  Although correctly dispersed, soot is unlikely to trouble the filter because it is well under 1µm in size. However, experience has shown that high levels, especially with dispersancy package failure, can lead to premature filter failure. 

In these scenarios, ß₁₅ > 1,000 is potentially the lower limit, although the quality of the fuel and lubricant may allow tighter levels.  In addition, the use of by-pass filtration may allow for even finer protection, as it involves a small percentage of flow via the relief valve and diverts directly back to the sump without concern for the pressure drop.

Bearing oils need to be as clean as possible to avoid abrasive wear and fatigue, especially in rolling element bearings with oil films as thin as 1µm.  However, in most cases, basic bearing oils are not highly complex in terms of additive formulations. Consequently, very fine filtration is possible with due care regarding the defoamant if it is used. 

On turbines with plain bearings, then a ß₇ > 1,000 is probably in order.  However, in the case of turbine oil systems, the filtration is generally in the pressure line, so attention needs to be paid to the differential pressure.  Therefore, it makes sense to consider off-line filtration, as it offers the benefit of a lower flow rate with minimal vibration, and the system does not need to be shut down for a filter change. 

In these instances, the off-line skid unit may also incorporate water removal.

Hydraulics are probably the most complex in terms of cleanliness requirements, and it is in these fluid power systems that I often encounter enthusiastic engineers overindulging in filtration.  Whilst hydraulics are usually the most susceptible thanks to their pumps and very fine clearances on the valves, the oils are also often formulated with defoamants, too.

Depending on the complexity, it may be a simple return line filter, but more complex ones will also have, or instead of, a pressure line filter.  Generally, the limit on hydraulic oil filtration is around ß₅ > 1,000.

Is Micron Size Alone Enough to Specify a Filter?

What irks me most is when people talk about filtration and discuss the micron rating without stating the Beta Ratio or Capture Efficiency. The observant amongst you will have noted that my guidance on the filter sizes stated above was with a Beta Ratio (ß) of 1,000 or a Capture Efficiency of 99.9%.  This is three times better than a Capture Efficiency of 90% or a ß of 10.

Consequently, in my experience, a ß₃ > 10 is no more harmful than a ß₅ > 1,000.   Just looking at the graphic below, we have three filters capable of stopping particles of 10µm, yet with widely different levels of performance.  Therefore, it is important to be specific about the performance as well as the micron rating. 

In summary, there is no absolute limit as there are a number of factors involved, not least the cost and ensuring that the return on investment is reached, which in itself will depend on the type and criticality of the system, so no, there is no easy answer to what the finest filter can use.

Varnish formation is one of the most critical and often overlooked challenges faced by industrial lubrication systems, especially in high-performance applications such as steam turbines, gas turbines, compressors, and precision hydraulic systems. Even when invisible to the naked eye, varnish compromises the reliability, efficiency, and service life of key components in industrial plants.

What is Lubricant Varnish?

Varnish is an insoluble by-product of the thermo-oxidative degradation of oils. Over time, these residues, usually brown to reddish-brown in color, adhere to metal surfaces, forming a thin, hard, and resistant film, similar to the varnish used on wood.

This deposit is composed of hydrocarbon oxidations, degraded additives, carbonized particles, and other byproducts of lubricant decomposition. The formation of this film occurs gradually and almost imperceptibly, making early diagnosis essential.

1. Studies published by turbine manufacturers, oil analysis companies, and organizations such as STLE (Society of Tribologists and Lubrication Engineers) indicate that More than 70% of the turbines that experienced recurrent failures had varnish buildup in the lubrication systems. In many cases, the varnish went unnoticed for years, silently accumulating until it interfered with the operation of servo-controlled valves and high-precision bearings.
2. Training and accession mechanism Laboratory research has shown that varnish arises from the thermo-oxidative degradation of lubricants, catalyzed by elevated temperatures, the presence of water, oxygen, and metal contaminants. These factors lead to the formation of free radicals and insoluble compounds that, over time, adhere to metal surfaces through electrostatic and chemical forces, particularly in areas with limited oil circulation or stagnation points.
3. Studies on behavior under different conditions. Experiments conducted by laboratories such as Chevron and ExxonMobil have shown that oils with different additive packages exhibit varying behaviors in varnish formation. Oils with higher phenolic antioxidant and amino content tend better to resist oxidation and the formation of insoluble byproducts. However, even with high-quality oils, if the rate of by-product generation exceeds the oil’s ability to keep them dissolved, varnish will inevitably form.

Consequences of the Presence of Varnish in Industrial Systems

The presence of varnish compromises not only performance, but also the safety and useful life of the assets. Among the main operational impacts, the following stand out:

• Locking of control valves and servo valves;
• Increased operating temperature in bearings and rotating components;
• Reduction of thermal efficiency by thermal insulation of the system;
• Increased energy consumption;
• Loss of operational reliability and increase in unscheduled downtime;
• Difficulty in maintaining the stability of the hydraulic system.

How to Identify the Presence of Varnish

Early detection depends on a structured analytical approach. Among the main laboratory methods, the following stand out:

ASTM D7843 – MPC (Membrane Patch Colorimetry)

This method measures the propensity of a lubricating oil to form insoluble deposits. By extracting and filtering a sample onto a membrane, filter browning is quantified numerically. MPC values above 30 are considered critical – an early and direct indication of the tendency to varnish formation.

ASTM D2272 – RPVOT (Rotating Pressure Vessel Oxidation Test)

This test evaluates the oil’s resistance to oxidation under accelerated conditions. The longer the time until pressure collapses, the longer the remaining life of the fluid. It is essential to indicate the degradation of antioxidant additives. Helps plan oil replacement before failure.

ASTM D6971 – RULER (Remaining Useful Life Evaluation Routine)

It uses voltammetry to measure the residual concentration of antioxidants in the oil. It provides an accurate analysis of the lubricant’s “chemical lung” by separating the types of antioxidants (phenolics and aminates). Quantitative indication of the chemical health of the lubricant.

ASTM D664 – TAN (Total Acid Number)

The TAN test measures the total acidity of the lubricant. The increase in this index indicates the presence of acidic products resulting from the oxidation of the oil, which are precursors of the formation of varnish and deposits. A continued increase in NHS may signal the need for intervention, even before visible contaminants form.

Other relevant tests include:

• FTIR (Infrared Spectroscopy): Identification of oxidation products, thermal degradation, and presence of polar contaminants;
• Particle Count (ISO 4406): Evaluation of fluid cleanliness and the presence of insoluble particles;
• Karl Fischer: Verification of the presence of free and dissolved water;
• VPR – Varnish Potential Rating: Composite index that combines MPC, FTIR, and operational data to predict the varnish formation trend.

 Varnish Prevention and Control Strategies

The most effective approach involves continuous monitoring combined with specific preventive and corrective actions:

• Off-line filtering with absolute elements or nanofiltration, ensuring removal of solid contaminants and varnish precursors;
• Strict humidity control, reducing the water content in the fluid to avoid hydrolytic reactions;
• Use of soluble varnish removal systems, such as ionic dry resin, treated cellulose, or electrostatic purifiers (ECR);
• Selection of lubricants with a high index of resistance to oxidation, preferably with modern antioxidant additives;
• Efficient thermal management, avoiding hotspots and stabilizing operating temperatures;
• Condition-based oil change planning and analysis instead of fixed intervals.

Tip: Implement critical varnish indicators in the reliability plan and integrate them into your predictive monitoring system.

Varnish is more than just waste: it is a marker of advanced lubrication system degradation. To ignore its presence is to accept the risk of serious failures and unexpected operating costs.

The solution? Adopt a predictive and proactive posture, with regular analysis, contaminant control, and use of modern technologies. This ensures performance, reliability, and longevity of industrial assets.

Hydraulic presses in Oriented Strand Board (OSB) mills are central and indispensable to OSB production. They exert an immense, uniform force required to compress wood strands and resin into durable panels, operating under exacting temperature and pressure conditions. The performance of hydraulic presses depends critically on the quality and condition of the hydraulic oil.

The Vital Role of Hydraulic Oil

Hydraulic oil in OSB presses serves multiple roles:

• Power Transmission: Hydraulic oil transmits power from pumps to press cylinders, enabling precise compression.
• Lubrication: Reduces friction in pumps, valve spools, and cylinders.
• Heat Transfer: Acts as a coolant, absorbing and dissipating heat from critical components.
• Sealing and Contamination Control: Prevents contamination ingress, maintaining system integrity.

Hydraulic Oil Failure: Oxidation and Varnish

Despite its crucial role, hydraulic oil is susceptible to failure, especially due to oxidation and subsequent varnish formation. Oxidation, a reaction with oxygen accelerated by heat, pressure, moisture, and catalytic metals, depletes antioxidants and generates harmful byproducts.

When oxidation takes hold, varnish becomes the silent killer of hydraulic precision.

Varnish, an insoluble, sticky deposit formed from these oxidation byproducts, accumulates on critical components, especially servo and proportional valves. This buildup is analogous to cholesterol plaque in arteries, restricting fluid flow, reducing responsiveness, and increasing operational risks.

Operational Impact of Oil Degradation

When hydraulic oil fails:

• Press Performance Suffers: Reduced valve responsiveness leads to inconsistent press forces, resulting in poor board quality and defective products.
• Maintenance Costs Escalate: Varnish buildup necessitates frequent component replacements, system flushes, and increased downtime.
• Energy Efficiency Drops: Oxidized, varnish-contaminated oil increases viscosity and blocks oil flow channels, raising power demands and operating costs.
• Safety and Environmental Risks Increase: Potential leaks and compromised components present significant hazards. Oxidized oil is known to deteriorate seals, leading to more leaking and increased risk.

Targeting Varnish at Its Source for Lasting Results

To combat these challenges, Fluitec and ExxonMobil developed Mobil Solvancer, an innovative oil-soluble cleaner. Mobil Solvancer dissolves varnish deposits effectively, analogous to a solvent clearing blocked pipes, immediately restoring system responsiveness. It also provides long-term protection, minimizing varnish recurrence, improving servo valve response times, and extending equipment life.

Inside the GP Clarendon Hydraulic Recovery Journey

GP Clarendon OSB Mill experienced significant varnish buildup in hydraulic systems after a prolonged shutdown, despite using Mobil DTE 25 and DTE 25 Ultra oils. Frequent servo valve failures were costing around $40,000 per quarter.

Identifying the Root Cause of Hydraulic Varnish

Analysis revealed high varnish levels indicated by elevated Membrane Patch Colorimetry (MPC) values (66dE). The mill implemented a 5% treatment rate of Mobil Solvancer (approximately 40 drums) combined with enhanced kidney-loop filtration.

Results Achieved

Within 2.5 months, remarkable improvements were observed:

• MPC values dropped from 66dE to 26dE.
• Ultra Centrifuge (UC) ratings improved from 4 to 1.
• Servo valve failures decreased from six per quarter to zero, showcasing substantial reliability improvements.

Ensuring Long-Term Reliability and Oil Health

With proven success, GP Clarendon scheduled a complete system oil change and plans to install permanent high-efficiency filtration in March 2025, ensuring long-term system integrity and performance.

Key Findings and Operational Takeaways

Effective management of hydraulic oil condition is crucial for maintaining optimal productivity and reliability in OSB mills. Mobil Solvancer demonstrates exceptional performance, significantly reducing varnish deposits, enhancing system efficiency, reducing maintenance costs, and ensuring consistent product quality.

As demonstrated by GP Clarendon’s experience, proactive maintenance coupled with Mobil’s industry-leading hydraulic oils can transform operational reliability in industrial hydraulic systems.

Over the years, the one thing that has always struck me is how few reliability teams work with their counterparts in the Health and Safety and Environmental departments.

Linking Lubrication to ESG and Sustainability Goals

To quote the guru, Ron Moore, in his article, “A Reliable Plant – Good for Personal and Process Safety”:

Compelling data from operating plants has been provided to demonstrate that “a reliable plant is a safe plant, is a cost-effective plant, is an environmentally friendly plant.” The reverse was also shown, that is, an unreliable plant is less safe, more costly, and less environmentally friendly.

This is something that I trot out in every training session, whether it be an awareness class or a certification preparation class.  Yet I sense there is still a “them and us” attitude between reliability engineers and their colleagues on the other side, and vice versa.

I want to focus on the environmental benefits in this article as they are fundamental to sustainability.  A quick trawl of LinkedIn and, of course, a rapid scan of most corporate mission statements, one is bound to see Sustainability mentioned.  Just how serious are we about this, or is it simply paying lip service to a perceived wish from the public at large?

I believe that the majority of the general public is concerned about the environment and the impact that it may have, and hence the proliferation of electric cars.  I believe companies are also concerned, perhaps more so as a result of the penalty to comply and the cost in terms of environmental damage and the punitive costs that result.

So, if companies are serious about sustainability, how can lubrication assist in the challenge for a more sustainable operation?

Why Reliability and Lubrication Are Sustainability Cornerstones

Let’s start with the issue of reliability.  Lubrication is, call it what you will, a cornerstone, a foundation block, or a core element of reliability.  Without a successful lubrication strategy based on best practice, reliability is doomed to mediocrity at best.

• When equipment runs smoothly, without unnecessary stops and breakdowns, then the emissions are lessened, and this also avoids the energy spikes that a start-up generates.
• With longer-lasting components and machines resulting from improved reliability, fewer emissions are created by re-manufacturing and shipping of the replacement parts and units.
• With longer lubricant life, there is less risk of spillages and leakages, and reduced deliveries to the site.
• With all the above, the strain on natural resources is diminished.

That, in a nutshell, is lubrication-focused sustainability.

Essentially, any business seeking to be more sustainable needs to put an effective lubrication strategy in place as part of its reliability drive.

However, that isn’t all of it. What else can be done to achieve greater levels of sustainability that also aid in the reduction of costs?

Reduction of costs? Surely sustainability costs?  For once, we have a win-win scenario!

Let’s start by looking at some of the simpler aspects.

Simple Lubrication Changes That Deliver Big Sustainability Gains

The first option is to switch from spin-on oil filters to simply replacing the elements.  A spin-on filter requires an element, as well as a core support tube and a housing, the latter two typically being of metal.  On disposal, this is a larger, heavier unit needing specialised disposal owing to the oil contamination.

However, going back to the traditional idea of a removable housing, with the core support tube as part of the filter head, then we have only the element to dispose.  This is something that the automotive industry has returned to, with all new cars now typically just needing the element replaced.  Here’s the win-win: less damage to the environment and cheaper element replacements.

Labyrinth or non-contact seals versus the elastomer lip seal are another opportunity, particularly with process pumps with significantly higher shaft speeds.  In addition to providing better sealing and reducing contamination ingress, the elastomer lip’s rubbing contacts cause less damage to the shaft, resulting in reduced friction and wasted power. 

However, work by Heinz Bloch showed that while the superior seals are more expensive, the life-cycle cost was still significantly less than that of the simple elastomer lip seal—another win-win scenario for the environment and the profits.

Reducing Waste and Costs Through Smarter Lubricant Handling

Buying lubricants in larger volume containers is a further opportunity for win-win. 

Going back to the mid-1990s, I recall many companies transitioning from buying lubricants in the 208L drums to buying in smaller 20L and 25L pails.  Similarly, grease transitioned from the 20kg and 25kg kegs to the 400g plastic tubes.  Understandably, this was partly a move to safer handling by having smaller packaging without the need for the handling equipment that heavy (more than 180kg) oil drums required, whilst 400g tubes of grease meant there was no longer the need to hand pack grease guns.

So why transition back to the older, less safe ways?  Again, sustainability, yet with a win-win situation.

In researching pricing, it is often the case that for a container of fifty times the quantity of grease, the cost is only ten times more than that of the 400g tube.  With oil, the proportionate volume differential from 20L to 208L to 1000L (ten times and 50 times, respectively) is eight times and thirty-six times, respectively.  In my experience, buyers are always looking for the lowest price on lubricants! 

Apart from the costs, think of the disposal issues associated with fifty plastic tubes compared to one metal pail. A further issue I find with the 20L and 25L pails, and even the smaller 400g tubes of grease, is the amount of waste.  Volumes of 1L or more of new oil are often disposed of as the pail is near empty, and some remaining new grease is often discarded in the 400g tubes, which, over time and a reasonable throughput of these small containers, adds up to a considerable cost and impact on the environment.

Balancing Bulk Purchasing With Safe Handling Practices

But what about the handling issues?  For many sites, such volumes are deemed unnecessary due to the numerous small-volume sumps. The volume of grease used is considered so low that it is not worth the larger volumes, especially given the health and safety risks associated with manual packing of grease guns, as well as the added contamination.

There’s an easy solution to these problems that addresses the issue of both safety and the environment, albeit at a small price of an investment.  Frankly, though, these would be part of any best practice strategy in any case, but it is useful to justify the installation by linking the safety and sustainability aspects to the reliability needs.

For the oils, the automated tank units allow for oil to be purchased in the 208L drums with dispensing into the smaller sealable and refillable containers.  This will require the use of appropriate handling equipment for the movement of the drums.

Images from Enluse/OilSafe

For the grease, the cleanest way to fill the grease, with caution, is to use a drum pump.  Most large containers of grease get left open and become contaminated, whereas using this method eliminates that problem.  Fit a grease nipple to the gun in place of the vent, and then backfill the gun via a pump fitted to the larger 20/25kg pail.

Do not over-pressurize while filling!

Just from some of the examples above, it can be seen that aspects of lubrication can contribute significantly to reducing waste as well as cost.  However, let’s keep in mind that irrespective of these, a reliable plant is a sustainable plant.  Any company pushing its sustainability agenda should start with reliability.

Over the past two decades, while conducting numerous Lubrication Benchmark Assessment audits across a wide range of industries—from Oil and Gas, refineries, petrochemical plants, and power generation facilities, I have witnessed one of the most neglected areas of machinery lubrication that has an enormous impact on the health of lubricant: the air breather.

In almost every audit, regardless of the plant’s size, automation level, or maintenance philosophy, the condition of installed air breathers—especially desiccant breathers—tells a consistent story of negligence. These components are the frontline defense for lubricant cleanliness, yet they are treated as accessories—something to check off during plant commissioning, and then forgotten.

The Reality on the Ground

During on-site audits and inspections, I frequently come across saturated, cracked, or in worst cases, even missing breathers on critical lubrication systems—gearboxes, hydraulic reservoirs, and lube oil tanks. In many such cases, the breathers were never inspected after commissioning. In others, they were bypassed completely, with open ports left exposed to ambient air contaminated with dust, humidity, and in some environments, chemical vapors.

A recent case at a cement plant perfectly illustrates how critical this oversight can be. A vertical gearbox driving the clinker conveyor failed catastrophically due to bearing seizure. It was a painful failure, not just in terms of downtime due to production losses but also in terms of what it revealed.

The gearbox breather was completely saturated, discolored, clogged, and non-functional upon inspection. Worse, it had not been checked or replaced for over a year. The ambient environment was rich in fine cement dust, mainly silica-based, which had found its way into the gearbox through the compromised breather.

“Airborne contaminants like silica dust and alumina particles are harder than bearing steel and can cause abrasive wear if they enter the lubrication system.”

We pulled the oil analysis history. The last two reports had already raised red flags:

• ISO 4406 Cleanliness Code of 24/22/19
• Ferrous wear metal content of 1348 ppm
• Significant dark sludge buildup at the sump

Lab tests confirmed that over 90% of the sludge was silica dust. No corrective action had been taken. Three months later, abrasive wear had escalated, leading to pitting and micro-spalling of the rolling elements. The bearings failed, and a key section of the plant came to a standstill with them.

The Tick-Box Mentality Needs to Change

I often see machinery vendors include basic breathers—mesh strainers or cheap cartridge types- during the procurement or project commissioning phase, to meet OEM checklists. These breathers are not selected based on the actual environmental risks of the plant. They are rarely tested for field durability in dusty, humid, or corrosive atmospheres.

Project teams—primarily focused on completion deadlines—tend to overlook these details. Once the handover is done, Operations & Maintenance teams inherit the reliability headaches. Unfortunately, breather degradation is not easily visible—until it’s too late.

Breathers: Passive Devices with Active Protection Roles

Air breathers are more than just accessories—they are active guardians of oil quality. Every time a reservoir breathes, ambient air gets pulled in or expelled. If that exchange occurs without proper filtration, dust, moisture, and vapors become uninvited guests in your lubricant reservoir, leading to degraded additive packages and accelerated machinery wear.

Desiccant breathers, when properly selected and maintained, perform three critical functions:

1. Moisture Control – Preventing reservoir water condensation, especially during daily thermal cycles.
2. Particulate Exclusion – Filtering airborne dust and debris before they reach the lubricant.
3. Headspace Pressure Balance – Allowing controlled airflow without creating pressure or vacuum buildup that could damage seals.

The Way Forward: Build Discipline Around Breather Maintenance

Contamination control must be a core pillar of any lubrication reliability program.

To avoid preventable failures, proper training of operators and technicians, as well as designing effective PM routines, is required.

• Routine Inspections: Technicians must be trained to check breather saturation (watch for silica color changes), assess airflow restriction (from clogging), and replace damaged units.
• Environmental Assessment: Selection of breathers should be site-specific, not one-size-fits-all. Plants with high humidity or heavy dust need robust desiccant or hybrid breathers.
• PM Program Inclusion: Breathers should be part of routine checks, like filters, not “set and forget” items. Condition-based replacement or defined interval-based change-outs should be part of your SOPs.
• Keep stock:  Breathers should be part of your spare parts inventory.

Lubrication Reliability Starts at the Breather

In the world of lubrication, we often focus on advanced filtration skids, high-end lab testing, and expensive sensors. But the real battle starts at the entry point—the breather.

Let’s change the mindset. Let’s stop treating breathers as cheap accessories. They are essential reliability tools. Recognize them as the first barrier against wear, moisture, and premature failure. Don’t wait for an oil analysis report to confirm what you could have prevented.

A few minutes spent inspecting or replacing them can save you weeks of downtime and thousands in repairs.

The battle for clean oil begins before oil analysis. It starts at the breather.

Solid Particle Cleanliness

In my previous articles, I have discussed how to achieve cleanliness within gearboxes and pumps, examining the entire aspect of solid particulate contamination ingress.

However, I was recently asked by an engineer following the above articles what a good target for cleanliness in these systems would be.

Cart Before the Horse

I probably should have written this article first, since the standard approach to improving reliability in terms of contamination control is as follows:

1. Set targets for the contamination levels within the system.
2. Undertake the steps to achieve the targets.
3. Measure to ensure the targets are met.

Many programs initially focus on the 3rd step, believing that simply performing oil analysis will prevent failure.  However, as I mentioned earlier in previous articles, this is akin to standing on the bathroom scales each morning and wondering why the hoped-for weight loss is not occurring.  The simple act of measuring is not going to achieve the desired reliability, and as with weight watching, the oil analysis reflects the lubrication lifestyle of the plant.

How Much Should I Weigh?

As with any proactive lifestyle change, we need a target weight.  Many years of medical research have shown that for a given height and gender, there are appropriate target weights.  Though the effort put in now will not be apparent until later in life, and more to the point, it is not a simple matter of the more weight we lose, the longer we will live.  Add variables to account for body shape and structure, etc., and it is not a simple calculation to set a target weight.

So What’s Involved in Setting a Target Cleanliness Level?

Probably the first aspect is the asset type, followed by the operating parameters, and finally, in my humble opinion, the desire to achieve the desired level of reliability.

Machine Type Influences

If we were to put the list of machine types in order from most to least tolerant of the solid particulate, then it would be:

Note that I have provided a generalized guide to the targets above. For those familiar with the ISO 4406:1999 Cleanliness Coding system for solid particles, hydraulics typically require a cleanliness level of around eight times cleaner than gearboxes.

There is a reason for this, and that is that when examining the clearances between components, complex hydraulic systems often feature valving with clearances of less than 5µm. In many cases, the high pressure and flow rate can lead to significant damage from solid particulates.

With gearboxes, however, gear teeth are generally hardened, and along with higher viscosity grades of lubricant, the solid particulate has a less significant impact on the wear rate.

Is a Cleanliness Target Necessary for a Gearbox?

Of course, it will still benefit from a reduction in wear rate and hence an increase in service life.  That said, though, the implementation, or Step 2, must not come at a price greater than the financial gains incurred by the cleanliness control.

As with any reliability initiative, there must be a financial incentive to justify any technical improvements.

But Surely the OEM Will Advise What This Should Be?

Indeed, the Original Equipment Manufacturer may well give a guideline value.  As mentioned, a reader contacted me, and he had approached several OEMs for clarification or had looked up the value in their documentation, which ranged from “not stated” to -/20/15 to 20/18/15 (ISO 4406:1999 solid particle reporting).

In my experience, OEM values are sufficient to avoid short-term and mid-term issues, but are inadequate concerning long-term reliability.  The cynical may suggest that the OEM wants the user to replace parts, regardless.  That said, there is a balance as an OEM does not want a reputation for poor reliability, either. 

More specifically, a value stated in the OEM documentation may not account for the worst-case scenarios in terms of environmental conditions and operating conditions, either geographically or in terms of the business’s nature.

What About the Nature of the Business Or the Environment?

Let’s consider the geography; some locations will be more prone to dust ingress, such as those in or near desert environments. Conversely, the issue is less prevalent in damp environments, such as at sea.  Concerning the industry, cement plants and mining/quarrying will again have higher levels of solid particulate than other industries.

Are There Other Factors to Consider When Adjusting the Target Cleanliness Level?

The cost justification has to be addressed, and therefore, other financial impacts include:

1. Capital cost
2. Repair costs
3. Downtime costs
4. Health and Safety risks
5. Potential energy loss costs

The greater these are, the cleaner the oil needs to be. 

Of course, to undertake a cost-benefit analysis, one must consider the additional costs of improved contamination control to achieve the target cleanliness levels, as well as the costs associated with monitoring these levels.  Once that is known, we can then verify it against the potential savings. Worked from the above expenses.

To establish the possible savings, however, it is essential to look at the existing history and any recorded “Mean Time Between Repairs/Rebuilds/Failures”.  Based on the research, we can then determine the potential life extension and calculate the resulting savings.

As with medical research, the Life Extension Tables serve as a useful guide to conservatively estimate potential gains.  In the image below, for every 1 Range Number improvement in the ISO 4406:1999, we have an incremental increase in life.  For gearboxes, this is not as great as with engines and hydraulics, but from around the 5 Range Numbers improvement (32 times cleaner), we start to see a significant gain.

Is It Worth It?

In my experience with gearboxes, few laboratories ever measure the solid particulate levels, with some suggesting that Ferrous Density is a better guide.  There are various reasons for this, not least the risk of choking the Automatic Particle Counter with large gear wear debris. 

Add in the fact that gear oil samples are often “wet,” leading to counting errors due to the thicker oil, and it is easy to see why most labs shy away.  However, Ferrous Density analysis, such as PQ (Particle Quantifier) or WPC (Wear Particle Concentration), does not offer a predictive view of potential failure, as Ferrous Debris is the end result of the wear process, not the cause.

Consequently, using particle-trending techniques such as a mesh obscuration instrument or a microscope to establish the level will reveal that gearboxes are often significantly dirty.  I have regularly seen ISO 26/23/21 on gear oils in some plants using mesh obscuration trending tools.  Yet, with little effort, this has been reduced to as low as ISO 14/11/9.

That would result in a 12-range number gain, putting the potential life extension factor at around 7 times.

Even being conservative, a more than 6 Range Number improvement is more than double the life currently experienced.

In summary, a Cost-Benefit Analysis is essential to setting a target.  Once the target is set, implement the improvements in contamination control and continually monitor to ensure the targets are being achieved.

• Determine the additional costs of filtration & Contamination Control
• Determine the Savings relating to the Life Extension
• Implement the 5-Year Cost-Benefit Analysis
• Seek Approvals

Targets must be optimized, feasible, and justifiable.