For documents not made public under § § 1.71-1.73 and 1.75-1.77 or by statute, access may be had only upon petition of the requestor made to and granted by the Commission.
52 Pa. Code § 1.74
This section cited in 52 Pa. Code § 1.72 (relating to formal case files); 52 Pa. Code § 1.77 (relating to extensions of time to review folders); and 52 Pa. Code § 5.349 (relating to requests for documents, entry for inspection and other purposes).