53 Pa. Stat. § 12714
It shall be unlawful for the city controller to countersign or for the city treasurer to pay warrants or checks for the expenditure of moneys from the city treasury for the erection or construction of any public building, except upon certificate of the directors that the specifications, drawings and plans of such public building have been prepared, drafted and executed by him, or under his supervision, or by an architect selected as above set forth, and that the work has been done to the approval of the director: Provided, That nothing in this section shall affect existing contracts, or existing drawings and plans of public buildings, or the countersigning or paying of warrants for such public buildings, or cases where such drawings and plans are actually in existence or have been actually commenced within one month after the effective date of this amendment.
53 P.S. § 12714