In the preparation of specifications for the erection or alteration of any public building, when the entire cost of the work exceeds the base amount of eighteen thousand five hundred dollars ($18,500), subject to annual adjustment under section 1802(a.2), the architect, engineer, or person preparing the specifications shall prepare separate specifications for the plumbing, heating, ventilating, and electrical work, and the township shall receive separate bids upon each of the branches of work, and award the contract for the same to the lowest responsible bidder for each of the branches.
53 P.S. § 56805