(1) Except as otherwise provided in subsection (2), the local unit of government, school district, or governmental entity that owns and operates the public playground equipment shall be responsible for the maintenance, repair, and upkeep of the public playground equipment according to the standards identified by this act.

  (2) For the maintenance, repair, and upkeep of public playground equipment that existed before the effective date of this act, the standards required by section 4 shall apply only to the extent that such application is possible without requiring substantial alteration, removal, or replacement of the existing equipment.