This chapter shall not apply to any existing or proposed buildings, or extension thereof, used or to be used by a public utility corporation, if, upon petition of the corporation, the Pennsylvania Public Utility Commission shall, after a public hearing, decide that the present or proposed situation of the building in question is reasonably necessary for the convenience or welfare of the public.

Should any article, section, subsection, paragraph, clause, phrase or provision of this chapter be declared by a court of competent jurisdiction to be invalid, such judgment shall not affect the validity of this chapter as a whole or any part or provision thereof other than the part so decided to be invalid or unconstitutional.

This chapter shall become effective five days after the date of final passage.