All buildings or structures which are structurally unsafe, not provided with adequate egress, which constitute a fire hazard, are otherwise dangerous to human life or which have remained vacant for over one year, which in relation to existing use constitute a hazard to health by reason of inadequate maintenance, dilapidation or obsolescence or do not conform to the provisions of this Building Code, are, for the purpose of this Building Code, "unsafe buildings". All such unsafe buildings are declared to be public nuisances and shall be abated by repair and rehabilitation or by demolition in accordance with the procedures found herein.