RCM Analysis - Failure Effects (Step 1)

The first of the 5 guides steps in IMS involves Failure effects. Failure effects should describe what would happen if no specific task is implemented to anticipate, prevent or detect the failure, and it is directly related to Question 4 of the 7 RCM questions: What happens when each failure occurs?  Note: This relates to the failure effects, formally known as the failure scenario.

A failure effect statement describes what would happen if a failure mode were to occur. Note that RCM makes a clear distinction between a failure effect (what happens) and a failure consequence (how, and how much, the failure mode matters). 

Failure effects statements are used to assess the consequences of each failure mode. They also provide the basic information needed to decide what failure management policies must be implemented to avoid, eliminate or minimize these consequences to the satisfaction of the owners/users of the asset.

The main failure management policy options include proactive maintenance tasks (on-condition, scheduled restoration, and scheduled discard), together with associated frequencies. If we wish to identify these tasks correctly, it is essential to assume that no proactive maintenance is being carried out, when identifying the failure modes and associated effects. In other words, in order to start from a true zero base, it is essential to assume that the failure mode does in fact cause the associated functional failure. Failure modes need to be described, and failure effect statements need to be written, accordingly.

The following text will be relevant here:

Function equipment: To regulate the pressure in the reaction section. 

Function item: To move the valve stem 

Spared/ Stand by: There are a by-pass and block valves.

a. Physical behavior of equipment on failure mode. Aging of bladder rubber, Bladder cracks and leaks, Actuator fails, Valve opens in a limited way. Reactor pressure too high, high pressure alarm/ trip.
b. Potential for consequential damage to equipment. No

c. How can the failure be observed? high pressure alarm

(Operators will act on indications in the control room like alarms, video cameras, gas detectors etc. [No observations in field]).

d. What action will the operator take on failure of the equipment?

Production: Reduce throughput to minimum, run over by-pass.
Maintenance: Priority repair of actuator. 

e. What are the production losses or other operational consequences on failure ?

(hours downtime, hours reduced production, HSE consequences).(incl repair)

Production loss: 8 hrs 75%.      Environment:  No   Health & Safety: No

At repair/ restore: is production loss encountered? Yes

The Failure Effects field is basically a free text field that explains the physical behavior of the Equipment under that Failure Mode. It involves a ‘cause and effect’ logic leading to operational consequences in the area of economics, health & safety and environment.

You can type it in – manually – in the free text field. Or, you can use the IMS-RCM has functionality to first insert the default part of the text.

This default text can be created, extended and modified in Settings\Maintenance\Common Data\Rich Text default. One can do this by opening a second sessions (right click) through connecting to IMS via a second screen tab in the browser (right click on the link).

The default text should hold the repetitive part of the Failure Effects text. The text specific to this Equipment/ Failure Mode can be added later, when this default is saved and inserted.

After providing the information for all aspects, a description of what happens when the failure occurs should be completed, listing the physical behavior of the Equipment under that Failure Mode.

This basically provides the ‘no maintenance situation’ of the RCM analysis.

Click Next when done.

The Failure Effects text editor has high level text editing capabilities with, for instance, also the ability to hold object links and hold images of drawings or pictures.

Note: the Failure Mode (FM) notes field is not used at this time.

Instruction video

For more information on the execution of RCM analysis in Guides Steps see instruction video: RCM Analysis Guided Steps Episode 7 Video.