Most internal audits are conducted by a staff professional internal auditor who is responsible for obtaining sufficient understanding about the process or entity under review. This includes an understanding the barriers that prevent the accomplishment of a desired objective and an understanding of controls in place that help ensure its achievement.
The auditor will not spend all of this time with you directly. Generally, the auditor will meet with you up front to get information on the unit or process under audit. Typically, he or she will need to document the effort and analysis involved in the review, which often can be done remotely. Actual time spent in your area varies, but in most cases, distraction to your daily routine is minimal.