It shall be the duty of every county institution district to require any person, copartnership, association or corporation entering into a contract with such institution district for the construction, erection, installation, completion, alteration, repair of, or addition to, any public work or improvement of any kind whatsoever, where the amount of such contract is in excess of five hundred dollars, before commencing work under such contract to execute and deliver to such institution district, in addition to any other bond which may now or hereafter be required by law to be given in connection with such contract, an additional bond, for the use of any and every person, copartnership, association or corporation interested, in a sum not less than fifty per centum and not more than one hundred per centum of the contract price, as such institution district may prescribe, having as surety thereon one or more surety companies legally authorized to do business in this Commonwealth, conditioned for prompt payment for all material furnished and labor supplied or performed in the prosecution of the work, whether or not the said material or labor enter into and become component parts of the work or improvement contemplated. Such additional bond shall be deposited with and held by the institution district for the use of any party interested therein. Every such additional bond shall provide that every person, copartnership, association or corporation who, whether as subcontractor or otherwise, has furnished material or supplied or performed labor in the prosecution of the work as above provided, and who has not been paid therefor, may sue in assumpsit on said additional bond in the name of the institution district for his, their or its use, and prosecute the same to final judgment for such sum or sums as may be justly due him, them or it, and have execution thereon: Provided, however, That the institution district shall not be liable for the payment of any costs and expenses of any such suit.