Contamination Control

The maintenance department is the cornerstone of any company that relies on equipment to generate profit. As the name suggests, the main function of this group is to maintain equipment, and prevent breakdowns. But when equipment failures overwhelm resources, the Maintenance Department can become the Emergency Repair Department, running from one problem to the next. This can become a vicious cycle of equipment failing due to lack of preventative maintenance, which can’t be completed because the resources are tied up dealing with breakdowns! Not only is this frustrating for everyone involved, but counterproductive in every sense.

There are, of course, many components within the maintenance departments scope of responsibility: Electrical, Mechanical, Pneumatic, and – the focus of this article – Hydraulics. It’s hard to think of an industry that doesn’t use hydraulic systems in some way. From simple assist circuits to complex critical lift systems, the world would cease to move without fluid power.

Over the years I’ve had the opportunity to work on a variety of hydraulic equipment, in several different industries – industrial plants, agriculture, construction, oil & gas – and each sector is unique in its own way. But one thing that remains constant across all industries is that 75 – 80% of all component failures in hydraulic systems are due to contamination. That’s a huge number to be attributed to a single issue, and when you consider that the cost of down time and loss of production is often much higher than the cost of repairing the hydraulic system, controlling contamination really starts to make sense.

I once worked for a company that handled repairs for a large meat packing plant. The plant was huge and employed hundreds of workers 24 hours a day. It was such a large-scale operation that they measured downtime in thousands of dollars per minute. If something as simple as a $300 hydraulic motor on a conveyor failed, it could cause a ripple effect throughout the whole plant. Even if they had a spare motor and could swap it out in 20 minutes it would still cost the company $40,000 because they had hundreds of workers doing nothing for 20 minutes, and production losses were enormous.

Now, not every company loses thousands of dollars a minute, but every company loses something when their equipment breaks down. The financial impact of equipment failure, whether it be from loss of production, damage to reputation or even loss of contracts, is usually much higher than the cost of the repair to the hydraulic system. It’s easy to pull a financial report that indicates costs allotted to the GL code labelled “HYDRAULICS”, but that’s only part of the story.  It’s important to consider this when you are assessing the true costs that are associated with contamination related failures.

So that’s the bad news about contamination in your hydraulic system. The good news is that you can get it under control and that will have an immediate impact on the number of component failures, and ultimately system failures that you incur.

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So Where Do We Start?

We start by recognizing that there are two main components to success – the machine component and the human component.

The machine component involves assessing the hydraulic system to determine what the cleanliness target should be, and ensuring that the components that make up the system are designed to achieve and maintain that cleanliness target. If the hydraulic components aren’t capable of controlling contamination, then it doesn’t matter what our people do; they won’t be successful. We need to ensure that we are setting ourselves up for success before we launch the program.

Assessing the hydraulic system is critical, and it’s important that this is completed by a fluid power professional who fully understands the many aspects of the system that factor into contamination control. These factors include: what components are used in the system and how sensitive they are to contamination, working pressure of the system, type of environment, and type of fluid used in the system. Each hydraulic system is unique, and must be assessed individually. Even separate hydraulic systems located within the same plant may have vastly different requirements.

Once the hydraulic system has been assessed and any changes that were required have been completed, we can move on to the human component. This involves the development of equipment specific training for the operational and maintenance groups. It’s very important that we involve both of these groups in the training, as each group has a vested interest in keeping the equipment running smoothly and each group has a specific role to play.

Some companies slip into the trap of allowing the operational group to run the equipment until it fails, and then it becomes the maintenance groups problem. We want to avoid this scenario altogether. Number one, it’s dangerous. Unexpected breakdowns lead to people rushing through tasks, lack of planning, missing steps, and even intentionally cutting corners in an effort to get the equipment back up and running. The workplace incident rate is much higher when workers are involved in breakdown repairs. It’s also expensive. Calling suppliers after hours to buy parts leaves no room for negotiation. You pay whatever they charge you – including after hours premiums. This scenario is just plain counterproductive. There is zero advantage to having an Emergency Repair Department running around trying to “Quick Fix” equipment.

It’s important that the operational and maintenance groups work together as a team. The goal isn’t to make fluid power experts out of these people; it’s to give them equipment specific training so that they have the tools they need to be successful at taking care of the basic fundamentals.

For the operational group, training means a better understanding of how the hydraulic system operates, including a closer look at the inner workings of specific components like filters. People are more likely to identify abnormalities if they understand how something is supposed to work. A simple daily checklist for the operator will help identify issues when they are minor and can be brought to the attention of the maintenance group. Once you have these two groups taking care of the basics, a lot of the bigger problems never materialize – and neither do the costs that are associated with them.

Let me give you an example. Let’s say that Lisa operates a hydraulic press in a large plant. She goes through her daily checks and notices that the clogging indicator on the return filter is nearing the end of the green zone. Because Lisa has had some training and knows how the filter system works, she recognizes that the return filter is nearing its dirt holding capacity, and will soon go into bypass. She notes this on the checklist which triggers a workorder for the maintenance group. Now the maintenance group can pull the correct filter, review the JSA, and plan to change the filter at the next shift change. That’s maintenance! It’s planned, it’s safe, and it’s cost effective. And the best part is that the cleanliness of the hydraulic fluid is never compromised. You maximize the service life of the filter without risking a spike in contamination due to running the filter in bypass.

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For the maintenance group training means hands-on coaching for the proper collection of oil samples, and how to interpret the results. I cannot overstate how critical this step is to the success of the program. Any corrective actions or changes to maintenance procedures are based on the results of the lab analysis. If the sample is low quality the program is low quality. Garbage in = garbage out. The cost of poor oil samples can be enormous both in terms of dollars and in resources. I know of a company that spent thousands of dollars, and hundreds of man hours trying to address water contamination in the hydraulic systems of multiple units. In an effort to bolster their preventative maintenance initiative, they had implemented an oil sampling program and instructed all maintenance personnel to send in regular oil samples for analysis.  When the sample results were reviewed, it was found that dozens of units within the same geographical area were testing positive for water contamination on a regular basis. A company was hired to travel to each location and either filter or replace the oil at a cost of $4k-$10k per unit. Within a few weeks the problem re-surfaced and the process began again. By the time I was consulted, (more than a year later) the company had spent over $500,000 trying to keep water out of the hydraulic oil. I began by visiting each location and asking the maintenance personnel to show me how they pulled the oil samples. Each and every one of them walked over to the drain valve on the bottom of the reservoir, cracked the ball valve and filled up the sample jar. As water is heavier than oil, it settles to the bottom of the reservoir, right next to the drain port. Since the laboratory measures water in ppm (parts per million), even a droplet of water (formed by normal condensation) would cause the sample results to come back “Positive Severe” for water contamination. Once sample ports were installed in the correct locations, and the maintenance personnel were properly trained on how to take samples, the water contamination problem went away – ON EVERY SINGLE UNIT. The company spent over $500,000 trying to fix a problem they never had!

For anyone seeking information, there are several ISO standards that may be referred to for guidance on correct sampling techniques, understanding particulate coding, and contamination control principals.

ISO 3722: Hydraulic Fluid Power – Fluid Sample Containers – Qualifying and Controlling Cleaning Methods.

ISO 4021: Hydraulic fluid power – Particulate contamination analysis – Extraction of fluid samples from lines of an operating system. 

ISO 4406: Hydraulic fluid power — Fluids — Method for coding the level of contamination by solid particles

ISO/TR 15640: Hydraulic fluid power contamination control — General principles and guidelines for selection and application of hydraulic filters

The fluid power professional who assessed the system will be able to provide guidance on establishing parameters for flagging the results. This not only relates to the particle count, but also to TAN (Total Acid Number), Viscosity, Water, etc. These parameters are unique to each system, and what is Normal for one system, may be flagged as Unacceptable, or Severe for another system.

I’ve designed hydraulic systems for drilling rigs working in the oil and gas industry, which is one of the harshest environments you can imagine. I’ve also designed the training for the operational and maintenance groups, including proper oil sampling techniques and how to interpret the results. Some of these rigs have been working in the field for more than 7 years and are still running the original piston pumps. They are also achieving cleanliness codes of 15/12/9. Anyone who is familiar with ISO 4406 knows that’s clean! That’s aerospace clean. It’s no coincidence that these two factors are related.

Controlling contamination in your hydraulic system is just one part of your preventative maintenance program, but in my opinion, it’s an important part because it pays dividends immediately, and it keeps paying dividends for the life of the equipment. I can assure you that the people working in your Emergency Repair Department will enjoy transferring into the Maintenance Department!

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