Machinery Lubrication Level I — Pewaukee, WI
Four days of intensive training on industrial lubrication best practices — lubricant selection, storage, filtration, and application. Built for those pursuing MLT I / MLA I certification.
When we think about the lube room, there can be a few images which come to mind. Either a pristine environment, with everything colour coded, neatly packed on the assigned shelves, dedicated storage and handling containers and a temperature-controlled environment (everyone’s dream!). Or we can have a mix of dirty, oily rags, creatively designed dispensing containers where the welders were definitely showing off their skills and mislabeled (or no labels) on the lubricants. We can also have many images in between since there is a range of things which can be done (or not done) by those in charge of the lube rooms given their environmental conditions and constraints (budgetary or operational).
Unfortunately, the lube room is the place where many failures can begin if the conditions are not appropriate. It should ideally be the first line of defense for our assets but is often overlooked. Typically, this is the starting point of the journey for any lubricant and if it carries contaminants then we are exponentially decreasing the life of our lubricated assets before they have a chance to operate in our facility. This article explores the ways in which we can reduce these effects and some areas of improvement for any lube room.
Addressing Contamination
The ISO 4406 test is one that the industry is very familiar with as it governs the cleanliness of the oil. Typically, every system / OEM has a targeted cleanliness level. But how does the cleanliness level actually impact the lubricant and its functions? It is often said that the industry runs on a film of oil that is between 1–10 microns. Essentially, that means that any particle which is larger than this range interrupts the film and can cause damage and wear to the components.
For those not familiar with ISO 4406, this quantifies the number of particles into three categories, ≥4μm / ≥6μm / ≥14μm particles per milliliter of fluid. Each category measures the quantity of particles that fit the size bracket and then these are translated to a scaled number. As such, the numbers represented are not the actual quantity of the particles of that size.
| More than | Up to and including | Scale Number |
|---|---|---|
| 2,500,000 | — | >28 |
| 1,300,000 | 2,500,000 | 28 |
| 640,000 | 1,300,000 | 27 |
| 320,000 | 640,000 | 26 |
| 160,000 | 320,000 | 25 |
| 80,000 | 160,000 | 24 |
| 40,000 | 80,000 | 23 |
| 20,000 | 40,000 | 22 |
| 10,000 | 20,000 | 21 |
| 5,000 | 10,000 | 20 |
| 2,500 | 5,000 | 19 |
| 1,300 | 2,500 | 18 |
| 640 | 1,300 | 17 |
| 320 | 640 | 16 |
| 160 | 320 | 15 |
| 80 | 160 | 14 |
| 40 | 80 | 13 |
| 20 | 40 | 12 |
| 10 | 20 | 11 |
| 5 | 10 | 10 |
| 2.5 | 5 | 9 |
| 1.3 | 2.5 | 8 |
| 0.64 | 1.3 | 7 |
| 0.32 | 0.64 | 6 |
| 0.16 | 0.32 | 5 |
| 0.08 | 0.16 | 4 |
| 0.04 | 0.08 | 3 |
| 0.02 | 0.04 | 2 |
| 0.01 | 0.02 | 1 |
| 0.00 | 0.01 | 0 |
Table 1: ISO 4406 rating scale.
Therefore, an ISO code of 20/15/13 represents:
| 20 | between 5,000 – 10,000 particles larger than 4μm in one milliliter of fluid |
| 15 | between 160 – 320 particles larger than 6μm in one milliliter of fluid |
| 13 | between 40 – 80 particles larger than 14μm in one milliliter of fluid |
New oil delivery in container sizes between a pail or a truck load, the cleanliness value can be excellent. Sometimes these values can be as clean as ISO 16/14/11, but can also be quite poor. A 16/14/11 score is great, but perhaps our turbines or hydraulic systems particularly those with EHC systems require something more stringent (due to their tighter clearances) such as ISO 14/12/9. The table below shows a comparison of what that actually means as it relates to the number of particles in the oil for these ratings.
| Particle Size | New Oil — ISO 16/14/11 | EHC System Spec — ISO 14/12/9 |
|---|---|---|
| >4μm | 320 – 640 per mL | 80 – 160 per mL |
| >6μm | 80 – 160 per mL | 20 – 40 per mL |
| >14μm | 10 – 20 per mL | 2.5 – 5 per mL |
Table 2: Comparing new oil to Turbine oil specifications for EHC systems.
As we see in Table 2, there is a major difference between the number of particles at the 4 micron level between what is being delivered to the facility as new oil versus what the turbine actually requires. When we translate that to the fact that bearings in turbines may run on a film of oil which is between 1–10 microns, and our new oil has potentially 640 particles that are bigger than 4 microns, then we can conceptualize that the oil film will most definitely be disrupted!
This ISO cleanliness level starts off from the entry of the “clean” lubricant into the plant. If we factor in drums which have been exposed to the atmosphere, dirty transfer containers which already contain contaminants or bad practices (leaving hoses open to the atmosphere), then the ISO contaminant ratings will significantly increase. This means we are literally pouring contaminants into our oils and our assets.
Thus far, we have only described the contaminants in the form of solid particles, but contaminants can also exist in the liquid form (fuel, water, other lubricants, process liquids) or gaseous form (air, process gases). These can all affect the lubricant either acting as catalysts or fouling the system.
The Unseen Failure Chain
When we think about starting from the lube room and tracing the chain of events which leads to failure, it will look similar to Figure 1 below.
Figure 1: Chain of failure events.
In this case, contaminants start off in the lube room, and they enter the equipment, wreak havoc and then lead to failure. During many failure investigations, the analyst stops at the physical root causes and can easily blame the component. Since they did not investigate further, they missed that the source of contamination actually came from the lube room and possibly bad storage and handling practices.
Mislabeling and Environmental Conditions
Thus far, we’ve spoken about the effects of mainly physical contamination but quite a number of things also happen in the lube room. One major aspect of compromise is proper labelling of the lubricants. Many times, technicians are in a rush to get their lube route underway and will often not double check that they have the correct lubricant for the application that they are working on. In these cases, they may have picked up the wrong lubricant which is not the appropriate viscosity or suited for the application either!
This can lead to incompatible lubricants being mixed causing a series of failures. It can also lead to incorrect viscosity being applied to the equipment causing wear and tear or efficiency losses. Additionally, if the wrong type of oil is used, this can also lead to severe bleaching of the additives out of the oil.
For instance, if a motor oil (which contains 30% additives) was placed in a hydraulic oil sump, this can lead to catastrophic events where the additives in the motor oil may trap water getting into the hydraulic oil making it emulsify rather than allowing the water to drop out.
As such, we need to ensure that there are adequate labeling systems in place to minimize the occurrence of a mix up with the lubricants. Colour coding can also help as this reduces the errors of “picking up” the wrong dispensing container especially when our technicians are in a hurry.
The environment has a huge role to play regarding the integrity of lubricants. If lubricants are stored outside in drums, they have the tendency to collect rainwater. They can breathe and draw in this rainwater which gets collected at the top of the drum. This breathing action occurs due to changes in temperature such as the change from a bright sunny environment to a rainstorm. This introduces water into the oil and contaminates it before it reaches the equipment. Lubricants should be stored at controlled temperatures between 0–25°C and in a sheltered area.
The Ideal Lube Room
While many may think it is costly or impossible to transform their current lube room, there are a few low-cost adjustments which can be made to help reduce the initiation of failure in this area. As shown in Figure 2, these small changes can have big impacts on reducing the contaminants which get into the oils before they are added to the machines.
Figure 2: Strategies for an Ideal Lube Room.
By implementing some of the aforementioned strategies, we can see an immediate reduction in the number of failures which occur at a facility. While many think about investing in predictive technologies which may range to the higher cost bracket, these simple adjustments to the lube room can easily solve a large percentage of the issues.
If we were to think about this in terms of the cost of the failures for gearboxes or other critical pieces of equipment, the investment in these strategies to upgrade your lube room is minimal. When investigating your next failure, perform a full root cause analysis and determine whether it’s stemming from your lube room. Chances are that you have the opportunity to prevent a lot more failures than you would expect.