---
title: "Software Step 4"
slug: "software-step-4"
status: "update"
updated: 2026-10-27T23:11:38Z
published: 2026-10-27T23:11:38Z
canonical: "ims-handbook.cenosco.com/software-step-4"
---

> ## 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.

# Software Step 4

## ![](https://cdn.document360.io/e492a0e0-a4ba-4aca-8fc6-76b95f91fdf3/Images/Documentation/SRBI%20(2)(1).jpg?sv=2026-02-06&spr=https&st=2026-10-28T13%3A43%3A49Z&se=2026-10-28T14%3A43%3A49Z&sr=c&sp=r&sig=Yo1p7iSULVoSq4vgYDPXf%2BBv7G006Ltmb67TZejx3ec%3D)

Step 4 Determine the most Credible Failure Scenario:

Below is explained how to implement Step 4 in the Software. See also [](/v414/docs/methodology-step-2)[Methodology Step 4](/v414/docs/methodology-step-4).

---

To start:

- After the [RBI Analysis has been started](/v414/docs/software-step-3).
- Select the Component – DM combination, to be risk assessed.
- Make sure that the assessment view is expanded to show the top section.

## Review the Operating Conditions

To review the Operating Conditions in IMS:

- Select the **Operating conditions** tab in the right section.
- Select the Product from the dropdown to lookup the Nf and Nh factors, AIT, FP, etc., if not already available. Note: If your product is missing you can request to have it added in [Settings \ Maintenance \ RBI Specific Data \ Product](/v414/docs/rbi-specific-data-settings).
- Click **Apply to specs** if desired.
- Use the [Liquid Release Calculator](/v414/docs/calculators)[](/v414/docs/calculators) or [Hole Size table](/v414/docs/hole-size-for-consequence-assessment) & [Release Rate plots](/v414/docs/release-rate-calculations) to determine the Release Rate.

![](https://cdn.document360.io/e492a0e0-a4ba-4aca-8fc6-76b95f91fdf3/Images/Documentation/software-step-4-image-v9e133o5.png?sv=2026-02-06&spr=https&st=2026-10-28T13%3A43%3A49Z&se=2026-10-28T14%3A43%3A49Z&sr=c&sp=r&sig=Yo1p7iSULVoSq4vgYDPXf%2BBv7G006Ltmb67TZejx3ec%3D)Select the **operating conditions** tab and select the product to look up the Nf and Nh factors.

Note: This information is specifically needed for the Detailed People Consequence Assessment in [Step 8](/v414/docs/step-8-rate-consequence-of-failure-cof).

## Review RBI Specs

To review the RBI specs in IMS:

- Select the **RBI Specs** tab in the left section.
- Review available specs (including the specs defined on the [Equipment](/v414/docs/pei-equipment-details-page) and [Component](/v414/docs/pei-components-details-page)).
- Click **Edit** to add additional specs.
- Click **Save**.

![A screenshot of a cell phone  Description automatically generated](https://cdn.document360.io/e492a0e0-a4ba-4aca-8fc6-76b95f91fdf3/Images/Documentation/software-step-4-image-d0u4z51k.png?sv=2026-02-06&spr=https&st=2026-10-28T13%3A43%3A49Z&se=2026-10-28T14%3A43%3A49Z&sr=c&sp=r&sig=Yo1p7iSULVoSq4vgYDPXf%2BBv7G006Ltmb67TZejx3ec%3D)RBI Specs.

Note: S-RBI specifications are used throughout the S-RBI assessment to document key material and process data needed for the assessment. Some of the specifications input in the S-RBI assessment are stored as specifications to ensure that there is only one set of data used.

## Review DM Attachments

To review the DM Attachments in IMS:

- Select the **Attachments** tab.
- Review the assigned DM documentation. Note: These can be imported via [Settings](/v414/docs/import-attachments-via-settings).

## Define the Credible Failure Scenario

To define the Failure Scenario in IMS:

- Select the **Criticality Assessment** tab.
- Click on **Scenario**.
- Click **Edit**.

![A screenshot of a social media post  Description automatically generated](https://cdn.document360.io/e492a0e0-a4ba-4aca-8fc6-76b95f91fdf3/Images/Documentation/software-step-4-image-xhvjhmut.png?sv=2026-02-06&spr=https&st=2026-10-28T13%3A43%3A49Z&se=2026-10-28T14%3A43%3A49Z&sr=c&sp=r&sig=Yo1p7iSULVoSq4vgYDPXf%2BBv7G006Ltmb67TZejx3ec%3D)Select the **Criticality Assessment** tab, click **Scenario**, and click **Edit** to enter the failure scenario.

- Described the Scenario, as [established by the S-RBI team](/v414/docs/methodology-step-4).
- Images and links can be added as well.
- Click **Save**.