(4) “Child-occupied facility” means a building, or portion of a building, constructed prior to 1978, which as part of its function receives children under the age of 6 on a regular basis, and is required to obtain a certificate of occupancy as a precondition to performing that function. The term “child-occupied facility” may include a preschool, and kindergarten classroom, and child development facility licensed under subchapter II of Chapter 20 of Title 7 [ § 7-2031 et seq.]. The location of a child-occupied facility as part of a larger structure does not make the entire structure a child-occupied facility. Only the portion of the facility occupied or regularly visited by children under age 6 shall be considered the child-occupied facility.