62 Pa. C.S. § 511
Unless otherwise authorized by law, all Commonwealth agency contracts shall be awarded by competitive sealed bidding under section 512 (relating to competitive sealed bidding) except as provided in:
Section 512.1 (relating to competitive electronic auction bidding).
Section 513 (relating to competitive sealed proposals).
Section 514 (relating to small procurements).
Section 515 (relating to sole source procurement).
Section 516 (relating to emergency procurement).
Section 517 (relating to multiple awards).
Section 518 (relating to competitive selection procedures for certain services).
Section 519 (relating to selection procedure for insurance and notary bonds).
Section 520 (relating to supplies manufactured and services performed by persons with disabilities).
Section 905 (relating to procurement of design professional services).
62 Pa.C.S. § 511