Passive IPLs

About Passive IPLs

A passive IPL can achieve its risk reducing function without the requirement to take any action or change the state of the system. For example, detonation arrestors and blast walls are passive IPLs that reduce the risk.

In LOPA, you can create a Passive IPL record for each type of passive IPL. This record stores the recommended probability of failure on demand (PFD) of the passive IPL device or system. The PFD value indicates the likelihood that the passive IPL system will fail to perform its safety function when required. The Passive IPL records populate the IPL Sub Type field in the IPL Checklist section of the Safeguard, which is of type Passive IPL.

Default Passive IPL Records

By default, the following Passive IPL records are available in APM:


Passive IPL ID	Lower Range	Upper Range	Default Value
Blast-wall/Bunker	0.001	0.01	0.001
Fireproofing	0.001	0.01	0.01
Open Vent	0.001	0.01	0.01
Underground Drainage System	0.001	0.01	0.01
Flame/Detonation Arrestors	0.001	0.1	0.01
Dike	0.001	0.01	0.01
Inherently Safe design	1E-06	0.1	0.01

Access a Passive IPL

Procedure

Access the LOPA Admin page.
In the left pane, select Passive IPL.
A list of available Passive IPLs appears.
In the Passive IPL ID column, select the link for the Passive IPL that you want to access.
In the Record Manager, the page for the selected record appears, displaying the datasheet for the record.
Note: To modify the Passive IPL, as needed, modify values in the available fields, and then select to save your changes. The values in the existing Safeguards that have used the modified Passive IPL will not be affected by the changes. If you want to apply the changes to an existing Safeguard, in the IPL Checklist section of the Safeguard, in the IPL Sub Type box, you must reselect the Passive IPL that you modified.

Create a Passive IPL

Before You Begin

For the Passive IPL that you want to create, you must create a System Code in the MI_PASSIVE_IPL System Code Table. The System Code Table populates the Passive IPL ID box. When you create the Passive IPL, in the Passive IPL ID box, you must select the value that you entered in the System Code Table.

Procedure

Access the LOPA Admin page.
In the left pane, select Passive IPL.
A list of available Passive IPLs appears.
In the upper-left corner of the workspace, select .
A blank datasheet for Passive IPL appears.
As needed, enter values in the available fields.
In the upper-right corner of the workspace, select .
The Passive IPL record is created.

Results

In the IPL Checklist section of the Safeguard of type Passive IPL, the Passive IPL that you created appears in the list of values in the IPL Sub Type box.

Delete a Passive IPL

Before You Begin

Before you can delete a Passive IPL, you must delete the corresponding System Code that you created in the MI_PASSIVE_IPL System Code Table.

Procedure

Access the LOPA Admin page.
In the left pane, select Passive IPL.
A list of available Passive IPLs appears.
In the row for each Passive IPL that you want to delete, select the check box.
In the upper-right corner of the workspace, the button is enabled.
Select .
The Delete Passive IPL dialog box appears, asking you to confirm that you want to delete each selected Passive IPL.
Select OK.
Each selected Passive IPL is deleted.

Results

In the IPL Checklist section of the Safeguard of type Passive IPL, the Passive IPL that you deleted does not appear in the list of values in the IPL Sub Type box.

Note: The values in the existing Safeguards that have used the deleted Passive IPL will not be affected when you delete the Passive IPL record.