Nothing in this chapter shall be construed to prevent the ordinary maintenance or repair of any property or area listed under the provisions of this chapter provided such work involves no change in design, color, texture, material or exterior appearance; nor shall anything in this chapter be construed to prevent any change, including the construction, reconstruction, alteration or demolition of any feature which, in the view of the City Manager, acting lawfully, is required for the public safety because of an unsafe or dangerous condition, or which is required for the provision of police, fire suppression or ambulance services.