What is reliability centered maintenance is answered by its questions. RCM asks, for each asset: what is it for, how can it fail to do that, what causes each failure, what happens when it does, how much does that matter, what can be done to prevent or predict it, and what if nothing can. The answers decide the strategy for that asset: a preventive interval, an inspection, a condition check, a redesign, or run to failure. This page walks the questions, says what they decide, and what reliability centered maintenance software does for a small team and what it does not.
The questions, in order
Function: what the asset is supposed to do, including the standard it is supposed to do it to. Functional failure: the ways it can fail to meet that. Failure mode: what causes each. Failure effect: what happens, from the operator's point of view. Consequence: safety, environmental, operational or merely economic. Task: what proactive work would reduce the consequence, and whether it is worth doing. Default: if no task is worth doing, what then, which may be redesign or run to failure. The order matters because the consequence decides how much effort the task deserves.
What the answers decide
A strategy per asset rather than one strategy for the site. Safety-consequence failures get a task whatever it costs, or a redesign. Operational-consequence failures get a task if it is cheaper than the failure. Economic-only failures are often best run to failure with a spare on the shelf. The output is the schedule: which tasks, on which assets, at which intervals, and a written reason for each. That reason is what distinguishes an RCM schedule from one copied out of the manual.
RCM against the FMEA and the manual
The manufacturer's manual gives intervals for a machine in general; RCM gives intervals for your machine in your operation, and often finds the manual's tasks over-maintain a low-consequence asset. The FMEA is the middle of the RCM process, the failure modes and effects; RCM adds the front, the function, and the back, the task decision. A plant that has done an FMEA is most of the way to an RCM schedule.
What the software does, and does not
Reliability centered maintenance software holds the analysis: the functions, modes, effects and decisions per asset, and turns the decisions into tasks in the CMMS. For a large plant that is worth having because the analysis is large. For a team with a few hundred assets the analysis fits in a spreadsheet, and the value is in the CMMS holding the resulting tasks and the history that tests them. No software answers the seven questions; people who know the equipment do.
Questions people ask about what is reliability centered maintenance
Is RCM only for aviation and power?
It was born there and it is heaviest there. A simplified version, the seven questions on the assets that matter, is used by plants and buildings of every size.
How long does an RCM analysis take?
Days per critical asset with the people who know it in the room. That is why it is done on the assets whose failure has a consequence, and not on the whole register.
Does RCM always reduce maintenance?
Usually it moves it: more on the assets that matter, less on the ones that do not. The total often falls, but the point is that the tasks left have a reason.