Campus policy requires that the Principal Investigator on a human subjects research protocol be a tenure or tenure-track faculty member, or meet the requirements for an exception.
If one of the exceptions outlined in the campus policy applies to your appointment, you will need to submit the "Request for Approval to Serve as Principal Investigator on Human Subjects Protocol" form completed by your department chair or supervisor, describing your experience with human subjects research protocols, your qualifications, etc. This form can be found here and should be submitted with each human subjects research protocol application. The Staff Reviewer of the protocol will then review form to ensure the PI Status is appropriate and can be granted.
It is important to note that serving as PI on human subjects research protocols is different from serving as a PI on a grant, and requires different standards to be met. There is no blanket PI status for human subjects research protocols.
Also, under no circumstances will the IRB approve students to serve as PI.
Additional information can be found here: https://research.wisc.edu/kb-article/?id=29557