How can I determine the frequency of special inspections as defined by the IBC?

[EnvResEng101]

So in the International Building Code, chapter 17, section 1705, there are a number of tables that list the required special inspections for certain areas, like concrete, soil, etc. The two types of special inspections are:

Continuous

Special inspection by the special inspector who is present continuously when and where the work to be inspected is being performed.

Periodic

Special inspection by the special inspector who is intermittently present where the work to be inspected has been or is being performed.

My question is: Since it is never stated, how frequently does the inspector need to be present during periodic inspections, or where can I find it? To me it seems they would need to be present when they see fit, or that they determine when they should inspect the job, but I can't find that explicitly stated anywhere.

Thank you.