53 Pa.C.S. § 8142
(a) General rule.— No bonds or notes shall be issued with a stated maturity date exceeding the sooner to occur of:
(1) Forty years from the date of the series of any bonds or notes issued to evidence debt for the purpose of financing the cost of actually constructing, acquiring or improving a project or a separately financed portion of a project or funding an unfunded actuarial accrued liability.
(b) Mandatory redemption and stated maturities or installments.— Bonds or notes may be serial bonds or notes or term bonds or notes or any combination thereof that may be selected by the governing body of the issuing local government unit. Except for bonds or notes issued to fund an unfunded actuarial accrued liability, if term bonds or notes are issued, the bonds or notes shall be subject to mandatory redemption, and, if serial or installment bonds or notes, the amounts of the stated maturities or installments shall be fixed: