All buildings or structures that are or hereafter shall become unsafe, unsanitary, deficient in adequate exit facilities, or which are or shall constitute a fire hazard, or are or shall become in any way dangerous to human life or the public welfare, or which, by reason of illegal or improper use, occupancy, or maintenance, are or shall become unsafe, shall be taken down and removed or shall be made safe and secure as the Chief Building Official shall deem necessary, and as provided in this Building Code or any other applicable laws, ordinances, or resolutions. A vacant building which is open to vandalism at door, window, or other openings shall conclusively be deemed a fire hazard and unsafe unless it is guarded in an approved manner.
(‘74 Code, § 150.51)