29 C.F.R. § 520.504
When will authority to pay student-learners subminimum wages become effective?
(a) Certification by the appropriate school official on an application for a special student-learner certificate shall constitute a temporary authorization. This temporary authorization is effective from the date such application is forwarded to the Wage and Hour Division in conformance with § 520.501.
(b) At the end of 30 days, this application shall become the permanent special student-learner certificate unless, after review, the Administrator denies the application, issues a certificate with modified terms and conditions, or expressly extends the period of review.