71 Pa. Stat. § 1791
The head of each administrative department, having under its jurisdiction any penal, reformatory or correctional institution, mental hospital, or any institution for feeble-minded or epileptic persons, for inebriates, or for juvenile delinquents and defectives, or any medical and surgical hospital, hospital for crippled children, sanitorium, or any charitable institution whatsoever within this Commonwealth, maintained in whole or in part by the Commonwealth, and whose boards of inspectors, managers, trustees, or directors are appointed by the Governor, shall certify to the Governor the names of employes of such institutions to act as police officers thereat. If the Governor shall approve the persons designated, he shall issue to each a commission, under which each employe shall have and exercise full power to make arrests, without warrant, for all violations of law which they may witness upon any part of the premises of the institution at which they are employed, and to serve and execute warrants issued by the proper local authorities for any violation of law committed thereon, and to arrest, with or without warrant, anywhere within this Commonwealth, any inmate of such institution that may have escaped therefrom, and to return him or her thereto. For such purposes and generally, on the premises of the institution at which they are employed, the persons so commissioned shall have all the powers and prerogatives conferred by law upon constables of the Commonwealth.
71 P.S. § 1791