What type of alteration is required when an emergency car top exit is added to an existing elevator?

Adding an emergency car top exit to an existing elevator typically qualifies as a modification that requires a significant degree of planning and adherence to safety regulations. This is because the installation involves structural changes to the elevator system, including potential adjustments to the elevator car, controls, and emergency procedures.

The addition of such a feature implies a modification to the original design and safety protocols of the elevator, necessitating compliance with the applicable codes and possibly requiring inspections and approvals from regulatory bodies. Therefore, it is generally recognized as a significant alteration rather than a minor tweak or temporary change, as it is aimed at improving safety and emergency responsiveness.

The correct answer highlights the various implications and the formalities involved in making such a modification to ensure that the elevator continues to meet safety standards and performs effectively under emergency situations.