A Reliability-Centered Maintenance analysis should be viewed as a serious exercise for your business. An RCM analysis is an investment that takes time, resources and money to complete.
As a result, we should always ensure that we are performing our analyses on assets that will show a return on the resources, time and money we invested in performing the analysis, implementing the tasks and performing the tasks.
Prior to starting a RCM analysis, one of the upfront tasks that must be completed is estimating the size of the RCM analysis and the time it will take to complete the analysis phase of the project. The size of your RCM analysis and the time it takes to complete the analysis is dependent on four things;
1. The number of components/functions contained in the envelope of the analysis.
2. The number of failure modes associated with these components/functions
3. The quality of information gathered prior to starting your analysis (how up-to-date are your drawings, OEMs and history?)
4. The experience of your RCM team and facilitator
A new RCM team with an experienced RCM facilitator should be able to complete 85 to 100 functions and 120 to 140 failure modes in a one-week session. Completing failure modes is defined as identifying the failure modes, listing failure effects and making RCM task decisions. As the team and facilitator become more experienced, the number of functions and failure modes will increase over time by as much as 30 percent.
To estimate the size and time it will take to complete a RCM Blitz analysis, select a critical asset and, using a P&ID drawing, begin highlighting and listing all the components within this system. Define a component as a modular asset that can be removed or repaired as a stand-alone item. For example, a gearbox is a component, a pump is a component, a limit switch is a component. While each component may contain several parts, the components are counted as a single item. Each will have one or more functions and can have several failure modes. Once you have completed your component list, multiply the number of components by 1.5; this will give you a estimated number of functions. Remember, you want to limit the number of functions in your first RCM to between 85 and 100.
Now that you have completed your component list, this will become the boundary of your RCM analysis. While other components outside this boundary may impact the performance or reliability of your asset, it is important to not list failure modes for components outside the boundary in this RCM analysis. These components and their failure modes may well be analyzed in your next analysis. Using your component list, you can now estimate the number of failure modes for your RCM analysis by using a failure modes estimating tool. The failure modes estimating tool contains a list of common failure modes for component types. As an example, let’s say we have a electrical motor as a component on our list. Looking at the estimating tool, we can see that a motor has five common failure modes:
Motor
1. Motor bearings fail due to contamination.
2. Motor bearings fail due to lack of lubrication.
3. Motor bearings fail due to over-lubrication.
4. Motor bearings fail due to misalignment of motor to gearbox.
5. Motor windings fail due to insulation breakdown.
For each component on the list, you will now estimate the number of failure modes associated with that type of component. It should be noted that the failure modes contained in the common failure mode list are not a comprehensive list of failure modes. It is a list of what we most frequently see as failure modes. This list should never be used to create a RCM “template”.
While these are common failure modes, we should never assume that these are the failures that your asset is experiencing. As you begin your RCM analysis, your team will develop your failure modes in accordance to what your asset is actually experiencing and what is likely to occur. Once you have noted the common failure modes for the components on your list, add up the total number of common failure modes. This will give you a estimate of the number of failure modes inside the boundary of your RCM analysis. Remember, you should limit the number of failure modes in your first RCM to between 120 and 140 failure modes.
Comments (4)
1) Posted 8:19 am, 17 June 2009 by Barry Snider
One thing I count on when I write a article and post it on the web is that people will read it with an open mind beginning with the title of course which in this case reads;
"RCM Blitz Analysis Estimating Tool"
In reading the rest of the article I am afraid I could not find a single place where Mr. Plucknette said he had the best approach, the fastest method, nor the only way to develop a maintenance strategy.
Having said that I would say is article if far more credible than your comment.
For anyone interested in learning about RCM I strongly recommend that you learn from a professional who has a reputation for being a leader in RCM.
2) Posted 1:19 pm, 30 June 2009 by Bob O'Connor
While there are other ways to develop a maintenance strategy or EMP, over the years traditional RCM regardless of methodology has been proven to be only effective way. While RCM does take money, time, and talent, every RCM analysis should be preceded by a business case so that we insure the implemented results provide a return on investment exceeding the cost of the training, analysis and implementation.
The best RCM providers understand where to apply the process and how to do so in the most efficient and cost effective way. This in fact is one of the reasons why RCM Blitz has been successful.
3) Posted 1:53 pm, 30 June 2009 by Doug Plucknette
RCM is not the only effective means to derive maintenance programs.
PM Optimisation using the PMO2000 method which seeks to find out what is missing from the current program (formal or informal) is considered more effective by those that use it.
RCM is ineffective becuase it starts from scratch. It was developed in the Aviation industry where they start RCM in the feasibility stage.
RCM was never designed for in service assets - it is quite ineffecient in such circumstances - at least compared to PMO2000.
That is the reason I developed PMO2000 - cos the function of RCM is to develop a maintenance program from scratch - yes if you run RCM on RCM - you find it fails the first question which is what is the function of the system. RCM's function is to derive maintenance program from scratch. the function of PMO2000 is to derive maintenance programs from the current program (formal or informal) or vender progam.
Regards
Steve
4) Posted 6:44 pm, 14 August 2009 by Steve Turner