If, in the preparation for the erection, construction and alteration of a public building, the entire cost of the work exceeds the amount specified or adjusted under section 1402(a) (relating to regulation of contracts), the architect, engineer or other person preparing the specifications may, if requested by the council, prepare separate specifications for the plumbing, heating, ventilating and electrical work. The person authorized to enter into contracts for the erection, construction or alteration of the public buildings may, if the separate specifications have been proposed, receive separate bids upon each of the branches of work and shall award the contract to the lowest responsible bidder for each of the branches.
Pennsylvania Legal Code