RCM Systems - Functions and Functional Failures

The Functions and Functional Failures section allow you to execute a "failure mode and effect" analysis in line with the first three of the seven RCM questions:

After the Functional Failures of the System have been stored in IMS-RCM, you must enter the Failure Modes of the prioritized Equipment, which can cause a particular Functional Failure of the System.
In this process step, one or more relevant Failure Modes are defined that will drive the RCM analyses.

It is emphasized that for the System there can be multiple Functions involved - there can be primary Functions and secondary Functions. In the HDS RCM ToR, the Functions and Functional Failures of the Systems are given, and copied below. This information is entered in IMS-RCM.

Function of the Reaction section is to treat 17.2 t/h diesel and remove 99.9 % sulphur.

• Functional failures of the Reaction system causing production loss are:

• Less than 17.2 t/h diesel throughput of the system

• Unable to heat the product to 350 °C at 17.2 t/h.

• Unable to remove 99.9 $ sulphur

• Product leakages with high H2S content causing plot clear.

The function of the Stripper section is to treat 17.2 t/h diesel and remove 99.9 % sulphur/H2S. Functional failures of the Stripper system causing production loss are:

• Less than 17.2 t/h diesel throughput of the system

• Unable to heat the feed of 15.4 t/h to 170 °C at reboiler

• Unable to keep stripper top temperature to 35°C

• Product leakages with high H2S content causing plot clear.

The function of the Recycle gas section is to feed H2 rich gas to the high pressure feed stream.

• Functional failures of the Recycle gas system causing production loss are:

• Compressor fails to deliver discharge pressure at rated gas-flow (2400 Nm3/hr)

• High H2S content causing plot clear around the compressor (and off-spec purge gas).

• Product leakages with high H2S content causing plot clear.

Note: When entering the "Functions and Functional Failures" be sure you have already defined at least a PLE regarding production loss in the site, check Settings/ Company/ Top Level/ Unit/ TA & Prod Loss, as this information is required now.

There are 3 ways to enter "Functions and Functional Failures" under a System:

1. Manually on the Systems Detailed Page.

2. Through Copy/Paste of existing "Functions and Functional Failures" from another System.

3. When importing a System with the import template.

Manually entering the Functions and Functional Failure 

To manually enter the Function and Functional Failures in the Systems details screen:

• In the Functions section click the Plus button.

• Fill in the Details of the Function.

• Click Save.

• Click on the Plus button to launch a New Functional Failure dialogue.

• Fill in the Functional Failure Details.

• Verify that the PLE is selected and present.

• To capture further information, use the detailed Description and Consequence fields.

• Click Save.

• Repeat the above steps to add more Functional Failures to the System.

Note: The tool allows PLE’s from other units to be applied in a System (and also in Analyses). This will be marked by a warning, see:

The PLE selection box provides the choice to select various PLE’s: Click Show All:

Copying existing Functions and Functional Failures

In addition to the editing functionality, also Copy and Paste functionality is available to copy Functions and Functional Failures between Systems. This might be helpful in case multiple similar Systems are involved:
After you clicked Copy, you can choose the Functions and Functional Failures to be copied. Opening the target System and clicking Paste will add the selected Functions and Functional Failures to the System. Note: Only Functions, Functional Failures and PLE’s from the source System will be pasted. The Equipment/Failure Mode combinations will not be pasted.

Importing Functions and Functional Failures

Also the Systems Import Wizard allows you to register Functions and Functional Failures for the Systems created.

See also RCM Systems - Creating / Importing.