In the case of a real and present emergency arising in connection with the operation and maintenance of the department of public service, including all municipally owned utilities, the department of public safety, or any other department, division, commission, bureau, or board of the municipality, the legislative authority of the municipality may by a two-thirds vote of all the members elected thereto, authorize the director of public service, director of public safety, city manager, board of public affairs, or other duly authorized contracting officer, commission, board, or authority, to enter into a contract for work to be done or for the purchase of supplies or materials without formal bidding and advertising.