53 Pa. Stat. § 42005
The officers and employes of any city, creating such fund and board, shall, upon the acceptance of this act, pay unto said board monthly an amount equal to three (3) per centum of their monthly salaries or wages, and if the council elects to make such payments, an additional amount not to exceed one per centum if deemed necessary by the council to provide sufficient funds for payments to widows and widowers of members retired on pension or killed in the service, except as hereinafter provided concerning laborers, which shall be applied to the purpose of this act.
If any compensation be granted to a person who has not been a contributor to the fund, as herein provided, for an aggregate period of twenty (20) years, such person shall be required to pay unto the board for the benefit of the fund, monthly, an amount equal to three (3) per centum of this compensation until such time as his contribution shall have been extended to a period of twenty (20) years.
If for any cause any person contributing to the fund who has served less than twelve (12) years shall cease to be in the service of the city, he shall become entitled to the total amount of the contributions paid into the fund by him, without interest. Any person, who has served for a period of less than twenty (20) years, and who has not reached the age of fifty-five (55) years, and who voluntarily retires from such service, shall be entitled only to the return of his total contributions to the fund without interest.
If for any cause any person contributing to the fund shall cease to be in the service of any city before he shall have become entitled to any compensation, the total amount of the contributions paid into the fund by him shall be refunded, in full, without interest: Provided, however, If any such person shall have returned to him the amount contributed, as aforesaid, and shall afterwards re-enter the service of the city, he shall not be entitled to the compensation designated, unless he shall return to the fund the amount withdrawn, in which event, the required period of service under this act shall be computed from the time he first entered the service of the city; otherwise the date of his period of service shall commence upon re-entry. In the event of the death of any person after he becomes entitled to any compensation and has not elected to retire, the total amount of contributions paid into the fund by him shall be paid over to his estate, without interest.
53 P.S. § 42005