Defining Barriers (LOPA)

When a LOPA is linked to a HAZOP Consequence during creation then the Barriers, copied from the Consequence’s associated HAZOP, will show here. The link will be indicated with a blue circled “H“ on the Barrier card.

If applicable you can create more Barriers or change the existing ones (all the changes, including the new Barriers will be synced back to the HAZOP).

You can choose (either when the LOPA is created form the HAZOP) or later when further defining the Barrier in the LOPA to use an Existing Barrier that is already used in another LOPA. Once the link is made, the Barrier card will display a yellow circle showing the number of LOPAs in which the Barrier is used. Hovering over this number will reveal the names of those LOPAs.

The Initiating Event Frequencies and the Barrier PFDs that you defined, will be used to calculate the SIL levels for the Consequence Categories. This can then be used to assess if the adequacy of the LOPA’s defined Barriers and if a SIF is needed.

(Further) Defining Barriers

To further define a Barrier:

• Click the fold-out bar to open the Barrier Properties.

• To use already defined PFD data from the IMS database, click Copy from Existing to copy the data from a Barrier already used in another LOPA, or click From Template to create a Barrier from a template, or click Replace with Existing. Note: You can also choose not to use any of these options and just fill the data directly in your local Barrier.

For all three options, the core Barrier properties will be copied, but the Validity settings will never be transferred, as they are specific to each LOPA (and linked HAZOP). Only when Replace with Existing Barrier is selected, will the P-A-C-E Category selections be preserved. Out of these three options only the Replace option ensures the exact same Barrier is used in both LOPAs. Take note that when you chose Replace with Exiting Barrier you cannot change it back to being a local Barrier in the LOPA, it will always sync back to the other LOPAs, even when you change its name (after the LOPA is Final Approved).

Take Note

When a Barrier is used in more than one LOPA, the following will apply when the Barrier is modified and the LOPA is subsequently Final Approved:

• A confirmation window will appear. If confirmed, any LOPAs (and associated SIF Analyses) that use this Barrier will revert to Draft, if they are not already in Draft.

• All changes to the core Barrier properties (so excluding P-A-C-E Category selections and Validity selections) will be applied to all LOPAs and SIF Analyses that use the Barrier.

• The PFD calculation button for these LOPAs will turn red and calculation will be required in order to approve the LOPAs again.

• The entry in Settings\Maintenance\SIS Specific Data\LOPA\Barriers will also be updated.

• After selecting one of the three options a popup will open:

  • Search for and select the appropriate Exiting Barrier or Template Barrier (or click + to create a new Barrier / Template).

  • Review the properties: PFD Low and PFD High.

  • Click OK (or Cancel) to close the popup.

• Add a Name. Note: The Name needs to be unique. When replacing with Exiting Barrier, it will already have a Name. If you change this, the other LOPAs using this Barrier will be impacted.

• Use the Additional Details field to add a description for the Barrier. Note: When replacing with Exiting Barrier, it will already have an Additional Details. If you change this, the other LOPAs using this Barrier will be impacted.

• You can change the Barrier Type (Control Barrier, Recovery Measure, or Conditional Modifier) in the fold-out details, or by dragging it to the relevant column. Note: When replacing with Exiting Barrier, if you change this, the other LOPAs using this Barrier will be impacted.

• When there are Safety Critical Elements (SCEs) search for and select the relevant Equipment. Note: These are summarized on the Safety Critical Elements Tab.

• Select the Category (e.g., BPCS). Note: When replacing with Exiting Barrier, you will already have a Category. If you change this, the other LOPAs using this Barrier will be impacted.

• When done, click X to close the fold-out.

• Select the applicable Consequence Categories (People (P), Asset (A), Community (C), Environment (E)). Applicable Categories are highlighted in blue. Note: By default when adding a new Barrier (depending on your site’s “Inactive PACE” application setting) either none of the P-A-C-E Categories or all of them will be selected - you can now change this. Only when a Barrier is Replaced with an Existing Barrier will the original P-A-C-E Category selections be preserved and in this case, if you modify these selections, any other LOPAs using that Barrier will also be affected.

• You can specify that a Barrier is Valid (green),  Partially Valid (PV) (yellow), or Not Valid (NV) (white) for a specific Initiating Event. Note: This will not impact other LOPAs if an Exiting Barrier is used, but off course the HAZOP will always be synced with the selection.

• Click the document buttons to write a Justifications (per Initiating Event).

  

When you are not making use of a Template or an Existing Barrier make sure to add the PFD as well:

• Click in the L and H section of the PFD and change the values. Note: If you are not defining PFD as a range, enter the same value in both L and H fields.

Adding a New Barrier

To create a new Barrier:

• Click the +Add New Barrier button.

To further define the Barrier see (Further) Defining Barriers.

Adding Existing Barriers

When adding an additional Barrier you can choose to use an Exiting Barrier that is already being used in other LOPAs. To do so:

• Click Add Exiting Barrier.

• Select the Existing Barrier and click OK.

When an Existing Barrier is added to a LOPA, all of its data — including the P-A-C-E Category selection — will be preserved and kept in sync across all LOPAs. However, the Validity selection (per Initiating Event) is LOPA-specific, so it is never copied from the Existing Barrier (nor synced between the LOPAs). The Validity setting is off course synced between the LOPA and linked HAZOP, but since you are adding the Barrier from the LOPA you will now need to specify the validity per Initiating Event.

Adding / Deleting / Merging

Use the Toolbar or Shortcut keys to Add / Delete / Merge Barriers.