Every organization wants to make sure their assets are reliable so that production runs smoothly. There are several approaches to maintenance aimed at maximizing an asset’s ability to perform at optimum levels. One such methodology is called reliability-centered maintenance (RCM).
But first, let’s take a step back and define what it means for an asset to be reliable. In maintenance management, an asset is reliable when it is affordable to run and maintain, and available to perform its desired function during as many working hours as possible. A reliable asset does not fail often and when it does, maintenance work can be done to restore its full function. Finally, reliable assets last a long time, meeting or exceeding the manufacturer’s projected lifespan and Mean Time between Failure ratio (MTBF).
What is Reliability-Centered Maintenance?
What is the reliability-centered maintenance definition? In short, reliability-centered maintenance is a maintenance strategy which identifies the company-wide functions and assets that are most critical to production with the goal of increasing asset reliability and availability by applying cost-effective maintenance methods to each critical machine or building. RCM closely examines assets to determine and categorize their most critical functions, as well as define their role in larger systems of the facility.
For example, breweries use grain storage tanks. These tanks must be airtight to keep the grains fresh until a new batch of beer is ready to be produced. The critical function of the tank is to keep raw materials in optimal storage conditions. If one of the tanks gets corroded and a hole forms in the metal from rust, its critical function has failed. This tank is part of the production line and if it fails, the batch cannot be produced because the raw material has been contaminated.
Similar to risk-based maintenance, reliability-centered maintenance also strives to focus scarce resources on assets that carry the most risk, or cause the most disruption when they are not running without failure.
Questions to Determine Most Critical Functions and Assets
In order to implement a reliability-centered maintenance methodology, an organization’s engineering and maintenance teams need to collaborate to determine which functions and assets are most critical. This can be done by asking a series of questions like the ones below and fully fleshing out the answers.
- What are the desired performance standards for each asset? What are their desired functions?
- In what ways can each asset fail to perform to its set standards?
- What are the causes of each failure?
- What are the failure modes for each failure?
- Why does each failure matter?
- What are the consequences of each failure (for every asset where RCM is being applied)?
- What can or should be done to prevent each failure?
- What can be done to predict each failure?
- If no preventive maintenance can be done in case of a specific failure, what action should be taken to minimize the cost of failure?
- How will each failure affect the end product and overall operational costs?
This series of questions is part of the SAE JA1011 standard. Similar questions may also be asked when a maintenance department decides to implement risk-based maintenance. While reliability-centered maintenance is used to determine which maintenance method is best for a specific asset, risk-based maintenance selects assets that specific maintenance programs should target. However, both of these strategies can be used together.
Applying Information Discovered through RCM Q&As
Of course, these questions do not have short, to-the-point answers, especially when they are applied to more than one critical asset. This exercise takes time, but it is essential for success in applying reliability-centered maintenance. While completing the preparation for using a reliability-centered maintenance method, there are several points to consider.
To begin, start with the absolute most important asset and work down in criticality from there. Identify the possible effects of this machine failing. If an asset is running 24/7, it may be most likely to suffer a failure when it nears the end of its lifecycle. Other failures can derive from harsh environments such as extreme temperatures, excess dust, or high humidity, which can lead to corrosion. While these failures are all too common, design or manufacturing flaws and human errors must also be considered.
When as many potential failures as possible are determined, the costs and effects of failures need to be quantified. Production process delays, employee safety, environmental safety, and the condition of the asset after each failure should be considered. It’s important to keep in mind that in some cases, replacing the asset is the most economical option.
When applying reliability-centered maintenance, the process should follow a cycle of decision, analysis, and action. Decide what assets are to be included in RCM, analyze the failures and effects of each failure, and take preventive action to avoid each failure, or correct them when they happen.
The 7 Steps of Applying Reliability-Centered Maintenance
Reliability-centered maintenance (RCM) follows multiple steps that should be applied to each asset that goes through the process.
Step 1: Select an Asset (or Assets) and Determine Criticality
The first step of following a reliability-centered maintenance methodology is to select an asset or assets and determine how critical they are to production. The purpose of the asset and the standards it needs to meet should be taken into account. Once the most critical asset or assets have been chosen, the next step can be taken.
Step 2: Define What System the Asset Is In
Next, it’s time to define what system the most critical asset is part of and the boundaries of the system which contains that piece of equipment. A critical asset can also be a structural one, such as a shipping warehouse facility. This can be a large or small system, but the inputs and outputs as well as the functions of the system should be well known.
Defining the system an asset is a part of is crucial because nothing exists in a vacuum. Every asset, when functioning properly or failing has a positive or negative impact on other assets, production, and costs. Take an HVAC system for example. If the blower motor for the air conditioner fan is broken, the unit will fail to cool the building. If the temperature in the building rises quickly, it will create humidity, which leads to condensation.
This condensation may form on parts of machinery that are sensitive to moisture, causing water damage. The water damaged machine may be part of the production line, which means production is stopped, delaying the end product from being made on time. This delay would then impact the bottom line. One seemingly unrelated, but essential part malfunctioning can lead to a ripple effect on a much larger scale. Knowing which machines could be affected by this scenario (and others like it) is an important step in the reliability-centered maintenance planning process.
Step 3: Define All Failure Modes
After the maintenance team knows what systems the most critical assets are a part of, the third step is to define all likely failures. This includes a wide range of failures from complete asset breakdown or major malfunction to a small part wearing out and needing to be replaced. Failure modes can result from several factors, including wear and tear of the machine, lack of preventive maintenance or inspections, mistakes in following safety procedures, and environmental factors like dust or moisture to name a few.
The type, amount, and severity of failure modes will largely depend on the industry the organization is in and the number, type, and age of the assets they have. The amount maintenance resources currently available will impact how often and how much preventive maintenance is done on a regular basis.
How Does an Organization Define Asset Failure Modes?
It is essential to discuss how an organization defines failure modes for their assets. Failure mode information is obtained by witnessing failures occurring and finding out what the causes of them are. However, this is not the only or best way to define failures. Many failures can be inferred before they happen. For example, technicians know that when a part wears out or a filter is clogged, machine failure is imminent. The maintenance guide from the manufacturer will help determine expected failures and the maintenance needed to prevent tor correct them.
To determine some failure modes before they occur again, maintenance teams can also look at the asset’s maintenance history, either through paper records, digital files, or by using computerized maintenance management system (CMMS) software. There are many types of failure modes that come about due to end-of-lifecycle failure, extreme operating environments, operator error, or design flaws.
The most systematic way to define failure modes is to carry out Failure Modes and Effects Analysis (FMEA). FMEA identifies any plausible issues and concerns that arise, referring to how, and the number of ways, a machine might fail and the potential negative effects of the failures.
Step 4: Identify Root Causes of Failure
Once all failure modes have been defined, the next step is to identify root causes of failure. This is vital for determining an approach to respond to, and solve, failures. Focus is placed on preventing problems rather than resorting to corrective maintenance after a machine failure occurs. It goes a step beyond troubleshooting—finding the root causes of failure is more systematic and organized. These root causes will vary for each critical asset an organization has. The time it takes to complete the process will depend on how many assets are considered in this process. However, RCM can be applied to one asset at a time.
Step 5: Assess Failure Effects
Perhaps the most important in the process, step five is to assess failure effects. Two popular techniques can be used to make this step more systematic and comprehensive:
- Fault Tree Analysis (FTA)
- Failure Modes and Effects Analysis (FMEA) (also used to define failure modes)
Regardless of which or how many of these techniques are used, questions should be asked such as:
- Does the failure mode have safety implications?
- Does the failure result in full or partial interruption of operations?
- What happens when each failure occurs?
- Would the failure be difficult to detect during normal maintenance operations?
- How would a failure on the asset impact the maintenance budget?
The answers to these questions look at the effects of failure from the critical assets determined in Step 1.
Step 6: Select Maintenance Tactics
Next, select a maintenance tactic for each failure mode on each asset. These tactics include preventive, corrective, predictive, condition-based, and run-to-failure maintenance. If a failure mode cannot be resolved with a preventive, condition-based, or predictive maintenance tactic, replacement or redesign of the asset should be taken into consideration.
Step 7: Implement and Review
The last step in applying a reliability-centered maintenance methodology is to implement the selected maintenance tactics. After the maintenance has been carried out, it’s important to review the process and results; then decide if changes to the RCM method need to be made.
A reliability-centered maintenance example would be using predictive maintenance on a laser printer for a packaging and label printing company. Commercial laser printers have a lifespan of approximately five years. Depending on the size of the company, one printer may be required to print hundreds or even thousands of pages per day. While this printer doesn’t fail often, when it does, it leads to significant stoppages in the printing workflow.
Failures other than complete asset breakdown that occur could be the light-sensitive drum surface wearing out, ink running low, or a software glitch. Depending on which of these or other failures occur, the costs of repair can be small to significant, and the breakdown effects minor to major. Since this machine is essential to production and breakdowns or replacements are costly, predictive and preventive maintenance would be the preferable types over corrective or emergency maintenance. Having a backup supply of parts that are likely to fail is the most effective method for avoiding significant downtime.
Benefits of Reliability-Centered Maintenance
There are numerous benefits of implementing a reliability-centered maintenance method, and all of them positively impact the bottom line.
Reliability-centered maintenance reduces equipment failures. When assets fail less, there are fewer defects in the end products and less waste is produced. It also minimizes unplanned downtime, which can be a result of a piece of equipment failing, or simply a machine malfunctioning. Asset overhauls, which include things like engine rebuilds are also minimized with RCM. It refocuses maintenance on ensuring tasks on critical assets are prioritized.
Finally, reliability-centered maintenance contributes to successful lean manufacturing. The tenants of lean manufacturing are zero defects, zero breakdowns, zero accidents, and zero waste. While it’s impossible to adhere to these tenets perfectly, lean manufacturing strives to remain as close to zero problems in those areas as possible. Minimizing waste is especially important—it is the core philosophy behind lean manufacturing. RCM helps to minimize asset downtime, which leads to fewer defects and less waste.
CMMS Software Helps Develop a Reliability-Centered Maintenance Methodology
CMMS software is vital for documenting all types of maintenance work, including preventive, corrective, condition-based, and predictive maintenance. This is essential for applying RCM, which can potentially use all of these work order types. Work order templates can be created in the software and be quickly edited for reoccurring tasks, specific instructions, or other information that is used repeatedly.
Asset service history is also available in CMMS software and that aids in troubleshooting. The ability to look back on maintenance work that was done in the past, how problems were uncovered, and what solutions were implemented can be helpful in solving current maintenance issues.
Assets at multiple locations can be easily managed and tracked. CMMS software stores all asset and equipment information in a single system, allowing technicians to quickly identify what equipment they have and where each asset is located.
Reliability-centered maintenance is all about classifying and tracking maintenance work and CMMS software helps to do just that. Maintenance reports are also useful during the review step in developing an RCM methodology.
Perfect your Reliability-Centered Maintenance with FTMaintenance
Using and perfecting a reliability-centered maintenance method is much easier with CMMS software such as FTMaintenance. Schedule a demo of FTMaintenance to learn more about our work order and asset management features which can help you develop your ideal maintenance strategy.