Notify Fire/EMS Department. Any person who discovers evidence of any actual, impending or extinguished, dangerous or destructive, or potentially dangerous or destructive, fire shall immediately cause notice of the existence of such fire, circumstances of same and the location thereof to be given to Public Safety Communications. This requirement shall not be construed to forbid that person or the person in control of a building or premises on which a fire exists from using all diligence necessary to extinguish such fire prior to the arrival of the Fire/EMS Department. Evacuation of buildings. Whenever a fire occurs in a building or there is reason to believe a fire exists in a building, the building shall be immediately evacuated and not reoccupied without the permission of the fire official in charge. If the building is provided with a manual fire warning system, it shall be the duty of any person who has knowledge of the fire to activate the manual fire warning system. Complete evacuation is not required when alternative procedures have been detailed in a fire plan which has been approved by the Fire Chief or authorized representative.