Below is an example of how the RBI NID is calculated.
Component Start Date
The Start date is a mandatory Component property that denotes the date the original Component has been put into use. It does not necessarily have to denote the actual Component, but any Component that has performed the specified function during the plant operation.
After the first Component has been created on the Equipment, the Start date will also be populated on the parent Equipment, even though here it is not mandatory.
As a matter of convenience, any Components created from that point onward will have the Start date prepopulated.
The same Start Date is also provided in both Equipment and Component Specs.
RBI LID & LLID
The central purpose of a Start Date is to serve as the basis of the RBI NID calculation. Provided that no Inspection History has yet been created, both RBI LID and LLID are going to be calculated based on the Component Start date and will serve as the basis of both NID and NLID calculation.
RBI Inspection History
In this example, we can see there are some changes to the LID calculation after the Inspection History has been entered. For the Inspection Date to be applicable, the History has to be marked as relevant for ATCR (or the Atmospheric Corrosion DM ). Further, we can see that LLID was not affected because the Inspection History was not marked as Legal/Location inspection. Thus, LLID is still being calculated as the Component Start date.
Take Note
Component Start date updates may influence the RBI NID (depending on the available Inspection Dates) calculation which in turn may send any Schedules that have said Component in their RBI scope into draft.