§ 51-a. Peepholes. In every multiple dwelling the owner shall provide and maintain a peephole in the entrance door of each housing unit. Such peephole shall be located, as prescribed by the department, but shall be so located as to enable a person in such housing unit to view from the inside of the entrance door any person immediately outside of the entrance door to such housing unit. The provisions of this section shall not apply to hotels or apartment hotels or to college or school dormitories.