Any successful business owner knows that having good products or services means very little without also having efficiently running equipment needed to produce them. Consider the impact of an unanticipated equipment failure that can range from a minor inconvenience to a major catastrophe. There is no argument that equipment malfunctions always cause some degree of disruption to production cycles and overall business operations. They not only affect the general course of business but they can also impact a company’s bottom line, especially when a company’s equipment is not routinely maintained.
What is a Reliability Centered Maintenance?
Reliability centered maintenance is the process of finding the best possible maintenance strategy for each asset in the organization. The theory behind it is that different assets require different styles of maintenance management. Some demand continuous high-tech monitoring while others are best left to the run-to-failure model. The classic example is light bulbs, which almost always have the lowest level of criticality. They are cheap to buy and carry in inventory. When they fail, there’s little to no danger or effect on productivity. Even the most junior tech can replace them. The process of finding the best strategy begins with an examination of breakdowns and the steps being taken to repair and maintain the assets.
The end goal of reliability centered maintenance is achieving consistently high levels of reliability at the lowest possible costs. The non-technical expression is “getting the most bang for your buck.”
Reliability Centered Maintenance Solution
As companies’ products and services rely more and more heavily on sophisticated equipment, the need for optimum efficiency has never been more important than it is today. Since time is money, margins are tight and competition is great, unexpected equipment malfunctions need to be avoided as much as possible. This is where Reliability Centered Maintenance comes into play. Simply put, RCM is designed to make sure that a company’s equipment performs as it is intended to do at all times and at the same time, safeguard the safety of the equipment tested. In order to identify or monitor flaws in equipment performance, RCM employs a number of maintenance task formats such as preventive maintenance (scheduled routine maintenance), predictive maintenance (maintenance based on past equipment repair history) as well as nondestructive equipment inspections (inspecting, testing, or evaluating equipment materials, components or assemblies for flaws without destroying its serviceability). When successfully implemented, RCM makes it possible for businesses to increase their overall efficiency and cost effectiveness by reducing operations downtimes and disruptions to its operations. RCM also provides business owners critical insights into the level of risk associated with the company they are managing.
The Development of Reliability Centered Maintenance
Reliability Centered Maintenance had its origins in the aviation industry. This is not surprising given the numerous parts and components that comprise aviation equipment, their heavy use and the most important, the high risks and potentially catastrophic consequences associated with aviation equipment failure. Since that time, the minimum criteria set out for RCM methods have been also implemented by a wide range of companies that have physical assets as well as a concern for their management. These RCM criteria are outlined in technical standard SAE JA1011 — Evaluation Criteria for Reliability-Centered Maintenance (RCM) Processes. (1998).
Reliability Centered Maintenance Criteria Explained
The minimum criteria specified in SAEJA1011 establish a basis for determining if the methods being used by a company are consistent with RCM processes. The criteria are set out in the following questions:
What is the item suppose to do and its associated performance standards?
This relates to identifying the system or equipment maintenance functions. In other words, this relates to how the equipment performs as well as its ability to meet company needs within the parameters of environmental safety and government standards. This information is available through manufacturer documentation that outlines specific functions of the equipment in question. It will also relate the scope of the functions as well as its limitations and methods of use as they pertain to any safety and environmental precautions. For example, an industrial weigh scale may have a weight limit that when exceeded may not be accurate or it may affect its functioning. The documentation will also outline the methods of use to ensure the most accurate measurements and safe use. This may involve methods of placing or handling items being weighed as well as the appropriate placement of the scale itself.
What does this asset do, how much of that is it doing currently, and how much of that would I like it to be doing?
For example, you have a conveyor belt that moves boxes. Currently, it’s moving 5000 boxes between breakdowns, and each of those breakdowns last about three hours. Based on a combination of what the belt’s manufacturer says, what your maintenance team says, and data in your CMMS Software, you think you can get that number up to 7000 boxes between breakdowns. Each breakdown can also be reduced from three to two hours.
In what ways can equipment fail to provide the required functions?
Simply put, this means being able to identify failure modes in a piece of equipment. In other words, it involves determining the nature of the equipment failure. For example, does the failure in question relate to one part or is it a systemic failure? The key is to identify exactly how a piece of equipment has failed, how often and does it involve the same equipment part. In companies with several pieces of the same types of equipment, it is important to determine if a particular failure is occurring systematically on all pieces or if the failure is limited to only one piece.
What are the events that cause each failure?
Further to identifying equipment failure modes, identifying the failure causes is also vital. It’s important to determine why, when and how equipment failures most typically present themselves. This is particularly true of heavy use equipment that may be subject to operating fatigue. As well, it is critical to identify at what point a piece of equipment may be most likely to fail and as above, in what way. By way of example, a water pump may be required to work 24/7. At some point, this piece of equipment will experience fatigue from constant use. Another common type of equipment stress or leading to failure is exposure to harsh environmental conditions such as heat, cold, water etc. Apart from these, there is also human error (i.e., improper use) and inherent design or manufacturing flaws that often cause equipment failure. Finding out the cause of the failure is important to understanding how to prevent or minimize it.
What happens when each failure occurs?
In order to improve operations, it’s not enough to simply identify equipment failures. It’s also important to know their effects. To begin, the effects of equipment failures presents in different ways; not just as a complete inability to function. For example, a failing piece of equipment may present as a decrease in its speed of operation or reduced quality of products. Ultimately, all forms of equipment failure impact productivity, operations and capital costs. They also lead to unplanned disruptions in production and high costs of repairs that may otherwise be avoided.
In what way does each failure matter?
This refers to identifying the consequences of failures. Apart from the financial and logistic consequences of equipment failure, the risks to safety for its operators as well as its environmental impact need to be considered. It also refers to how a failure impacts the integrity and condition of the piece of equipment as a whole. Maintenance technicians need to be aware of the potential risks associated with a “band aid” fix without careful consideration to the overall functioning of the equipment.
What systematic task can be performed proactively to prevent, or to diminish to a satisfactory degree, the consequence of the failure?
The answer to this question is hiding inside the asset’s maintenance and repair history. By looking at what was done and when, you can start to see breakdown patterns. Once you have the pattern, you can start to slot in proactive preventive measures between breakdowns. For example, the conveyor belt generally runs fine for about 5000 boxes before requiring some sort of repairs. If you add visual inspections after every 4500 boxes, you have a good chance of stretching out your uptime.
But be careful; the wording of this question can be a bit misleading. It’s about what can be done, but you also have to consider what should be done. There are situations when you should take steps to avoid breakdowns. But there are also situations where it’s going to be better to simply continue to use the run-to-failure maintenance strategy. When the cost and trouble of avoiding breakdown is more than the value of the increased uptime, it makes more sense to just let things run until they fail. Back to the classic example, think light bulbs.
What must be done if a suitable preventive task cannot be found?
Here we’re dealing with a very specific situation: the best maintenance strategy is not run to failure, but at the same time we can’t find a good proactive preventive maintenance plan to apply. Imagine you have an old A/C unit in your machine shop. In fact, it’s so old that you can’t source parts for it anymore. And it runs on a coolant that used to be common but is now in the process of being phased out. You can’t maintain it by refilling the coolant and you can’t repair it by switching in new parts.
Because you can’t set up a maintenance strategy, all you can do is have a plan in place for when the A/C inevitably dies. That might mean having money already set aside in the budget to buy a replacement. It might mean borrowing a unit from another department’s inventory. There’s no perfect answer, but you want a solution that can be implemented quickly, with the least amount of disruption.
As you work through the seven questions, you find the best possible strategy for each asset. It’s important to remember that your answers can change over time. Any given asset can shift in criticality, and the costs associated with different maintenance strategies can increase or drop due to a number of external and internal factors.
Implementing a Reliability Centered Maintenance Program
Organizations need to begin by looking at their assets in terms of criticality. Basically, they ask themselves, “How bad is it if this asset fails?” Factors such as costs for maintenance and labor, chances for injury, environmental damage, lost productivity, and compliance-related fines need to be considered. Once, they’ve determined criticality, the assets can be ranked from most to least critical.
Starting from the top, each item on the list is examined using the seven RCM questions. Based on the answers, the organization determines the best maintenance strategy for each asset.
Crucially, RCM is an on-going process. Organizations need to periodically revisit earlier decisions, ensuring that their maintenance strategies change as business goals and asset criticality evolve. For example, the best maintenance strategy for an asset early in its useful life is different from the one that’s the best fit 15 years later. And even though predictive maintenance did not make economic sense for an asset five years ago, it might be the best choice after the price of sensors has dropped.
Implementing a Reliability Centered Maintenance program adds value to a wide range of companies. RCM makes it possible for business owners to maintain the integrity of their equipment and all their components, extend their assets’ lifespans, eliminate unplanned shutdowns, lessen safety and environmental risks and reduce overall maintenance costs. All things considered, RCM offers efficiency, safety and long term cost savings.
SAE JA1011 Evaluation Criteria for Reliability-Centered Maintenance (RCM) Processes, Society of Automotive Engineers, 1998.