(a)   As set forth hereinafter, the procurement code shall specify conditions precedent to and procedures applicable to competitive sealed bidding. As alternatives to competitive sealed bidding, the procurement code may specify conditions precedent to and procedures applicable to the use of one or more of the following methods of procurement: Competitive sealed proposal; small purchase procedures; special competitive selection procedures; and special purchase procedures. Such methods shall be as set in the 1982 Charter or the ordinance adopted thereunder in effect on the effective date of this charter until amended by the board of mayor and aldermen. Any such amendment shall conform with the laws of the State of New Hampshire. No such amendment shall eliminate the requirement for procurement methods as set forth herein but may change the provisions of such procedures for the good of the city.
   (b)   The city shall not preclude, otherwise qualified businesses or individuals of the City of Manchester from participating in the bidding process. In so far as it is possible, the city shall encourage local businesses to participate in the bidding process.