--- title: "MEI in PEI" slug: "mei-in-pei" updated: 2026-10-27T23:11:38Z published: 2026-10-27T23:11:38Z canonical: "ims-handbook.cenosco.com/mei-in-pei" --- > ## Documentation Index > Fetch the complete documentation index at: https://ims-handbook.cenosco.com/llms.txt > Use this file to discover all available pages before exploring further. # MEI in PEI The Maintenance Efficiency Index (MEI) for PEI is calculated based on the RBI Assessment and shown in the RBI Assessment as well as on the linked Schedules. ## The MEI calculation The Maintenance Efficiency Index (MEI) is the ratio of annual risk reduction to annualized cost of performing equipment care tasks. ![](https://cdn.document360.io/e492a0e0-a4ba-4aca-8fc6-76b95f91fdf3/Images/Documentation/pic%201(238).png?sv=2026-02-06&spr=https&st=2026-10-28T14%3A21%3A19Z&se=2026-10-28T15%3A21%3A19Z&sr=c&sp=r&sig=UWQ1JwcctG84aSMHuPGeWfuD4ef4cdeCnZWPQwXtR1E%3D) Where: POC = Price of Conformance = Inspection, Maintenance & Replacement Costs PONC = Price of Non-Conformance = S-RBI Consequence of Failure (CoF - Asset) ETBF = Estimated Time Between Failure = Remaining Life or Design Life ETBC = Estimated Time Between Consequence = N x RL (default is 5xRL with 100 years being the max). Note: Although the default N value is 5, every site can set their own default via the [Application Setting](/v414/docs/application-settings): "MEI ETBC default multiplier". Thus, in terms of RBI this becomes: ![](https://cdn.document360.io/e492a0e0-a4ba-4aca-8fc6-76b95f91fdf3/Images/Documentation/pic%201(239).png?sv=2026-02-06&spr=https&st=2026-10-28T14%3A21%3A19Z&se=2026-10-28T15%3A21%3A19Z&sr=c&sp=r&sig=UWQ1JwcctG84aSMHuPGeWfuD4ef4cdeCnZWPQwXtR1E%3D) By default, MEI is only calculated for Category 2 and Category 3 Schedules, and only when linked to RBI Assessments. ## Where the MEI can be seen The MEI value and its inputs are shown in the [RBI Assessment](/v414/docs/step-3-start-rbi-analysis-and-assign-dms-to-the-component-1), on a separate **MEI** tab. (For old RBI Assessments you will need to edit the Criticality Assessment before the MEI will update.) ![](https://cdn.document360.io/e492a0e0-a4ba-4aca-8fc6-76b95f91fdf3/Images/Documentation/pei-release-3.14-image-87uai191.png?sv=2026-02-06&spr=https&st=2026-10-28T14%3A21%3A19Z&se=2026-10-28T15%3A21%3A19Z&sr=c&sp=r&sig=UWQ1JwcctG84aSMHuPGeWfuD4ef4cdeCnZWPQwXtR1E%3D)Click MEI to see the MEI tab with input values.The MEI will also show on the linked [Schedules](/v414/docs/defining-inspection-schedules) (by default only Category 2 and Category 3).![Graphical user interface Description automatically generated with medium confidence](https://cdn.document360.io/e492a0e0-a4ba-4aca-8fc6-76b95f91fdf3/Images/Documentation/Screenshot_239.jpg?sv=2026-02-06&spr=https&st=2026-10-28T14%3A21%3A19Z&se=2026-10-28T15%3A21%3A19Z&sr=c&sp=r&sig=UWQ1JwcctG84aSMHuPGeWfuD4ef4cdeCnZWPQwXtR1E%3D)Click the **MEI** button in the Schedule’s “Plan codes” section to see the MEI input values. ![Graphical user interface, application Description automatically generated with medium confidence](https://cdn.document360.io/e492a0e0-a4ba-4aca-8fc6-76b95f91fdf3/Images/Documentation/Screenshot_240.jpg?sv=2026-02-06&spr=https&st=2026-10-28T14%3A21%3A19Z&se=2026-10-28T15%3A21%3A19Z&sr=c&sp=r&sig=UWQ1JwcctG84aSMHuPGeWfuD4ef4cdeCnZWPQwXtR1E%3D)When you click the **MEI** button, the MEI inputs are shown. They cannot be edited when linked to an RBI Assessment. The MEI will also be shown as a column in the RBI grid.On the [Schedules Main Screen grid](/v414/docs/schedule-main-screen) the Lowest MEI can be shown. But by default, it will be hidden. In the grid settings the Lowest MEI column can be added to the grid. The lowest MEI is shown in this case, since Schedules can be [linked to more than one RBI Assessment](/v414/docs/mei-in-pei#schedules-linked-to-more-than-one-rbi-assessment). ## Enabling MEI for Category 1 Schedules Category 1 Schedules are intended to be used for mandatory/code driven and jurisdictional tasks, for this reason MEI is normally not applicable and thus, by default, not calculated. However, it is still possible to be calculated and shown. In this case it must be activated in **My Account** (see [Navigating IMS Main Menu Items](/v414/docs/basic-navigation-main-menu)).![Graphical user interface, application Description automatically generated](https://cdn.document360.io/e492a0e0-a4ba-4aca-8fc6-76b95f91fdf3/Images/Documentation/pei-release-3.14-image-9ym733pu.png?sv=2026-02-06&spr=https&st=2026-10-28T14%3A21%3A19Z&se=2026-10-28T15%3A21%3A19Z&sr=c&sp=r&sig=UWQ1JwcctG84aSMHuPGeWfuD4ef4cdeCnZWPQwXtR1E%3D)To show and calculate MEI for Category 1 Schedules, you must check the option in **My Account**. ## When Schedules not linked to RBI Assessment In PEI the MEI is only calculated for Schedules linked to an RBI Assessment, since the “Asset” Consequence of Failure (CoF) is needed. However, when not linked to an RBI Assessment, users can estimate the inputs to the MEI calculation directly on the Schedule. In thus case it will this be possible to *Edit* the MEI on the Schedule.![Graphical user interface, application Description automatically generated with medium confidence](https://cdn.document360.io/e492a0e0-a4ba-4aca-8fc6-76b95f91fdf3/Images/Documentation/Screenshot_241.jpg?sv=2026-02-06&spr=https&st=2026-10-28T14%3A21%3A19Z&se=2026-10-28T15%3A21%3A19Z&sr=c&sp=r&sig=UWQ1JwcctG84aSMHuPGeWfuD4ef4cdeCnZWPQwXtR1E%3D)For Schedules, not linked to an RBI assessment, an **Edit** button is available in the MEI section. ## Schedules linked to more than one RBI Assessment When a Schedule is linked to more than one RBI Assessment, then the lowest MEI will be shown.